TY - JOUR TI - InGaN/GaN quantum-well heterostructure light-emitting diodes employing photonic crystal structures AU - Wierer, J. J. AU - Krames, M. R. AU - Epler, J. E. AU - Gardner, N. F. AU - Craford, M. G. AU - Wendt, J. R. AU - Simmons, J. A. AU - Sigalas, M. M. T2 - Applied Physics Letters AB - Electrical operation of InGaN/GaN quantum-well heterostructure photonic crystal light-emitting diodes (PXLEDs) is demonstrated. A triangular lattice photonic crystal is formed by dry etching into the top GaN layer. Light absorption from the metal contact is minimized because the top GaN layers are engineered to provide lateral current spreading, allowing carrier recombination proximal to the photonic crystal yet displaced from the metal contact. The chosen lattice spacing for the photonic crystal causes Bragg scattering of guided modes out of the LED, increasing the extraction efficiency. The far-field radiation patterns of the PXLEDs are heavily modified and display increased radiance, up to ∼1.5 times brighter compared to similar LEDs without the photonic crystal. DA - 2004/// PY - 2004/// DO - 10.1063/1.1738934 VL - 84 IS - 19 SP - 3885-3887 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000221210100055&KeyUID=WOS:000221210100055 ER - TY - CONF TI - Repeatability and intercorrelations of sensory and cognitive tests in unmedicated elderly subjects AU - Schiffman, S.S. AU - Murray, S.G. AU - Watson, E.L. T2 - 2004 AChemS annual meeting C2 - 2004/// C3 - Proceedings of the 2004 AChemS annual meeting CY - Sarasota, FL DA - 2004/// PY - 2004/// ER - TY - CHAP TI - Taste and smell AU - Schiffman, S.S. T2 - Nutrition care of the older adult: a handbook for dietetics professionals working throughout the continuum of care A2 - Niedert, K. C. A2 - Dorner, B. PY - 2004/// ET - 2nd SP - 89-93 PB - Roche Dietitians ER - TY - JOUR TI - Smell and behavior AU - Schiffman, S.S. T2 - ENT News DA - 2004/// PY - 2004/// VL - 12 IS - 6 SP - 52–53 ER - TY - CONF TI - Power Packaging Techniques and High Current Applications AU - Hopkins, Douglas C. T2 - 19th Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC) C2 - 2004/2/22/ C3 - 19th Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC) CY - Anaheim, CA DA - 2004/2/22/ PY - 2004/2/22/ ER - TY - CHAP TI - Introduction to Olfaction: Perception, Anatomy, Physiology, and Molecular Biology AU - Schiffman, Susan S. AU - Pearce, Tim C. T2 - Handbook of Machine Olfaction AB - This chapter contains sections titled: Introduction to Olfaction Odor Classification Schemes Based on Adjective Descriptors Odor Classification Based on Chemical Properties History of Structure-activity Studies of Olfaction Odor Structures Associated with Specific Odor Classes Based on Qualitative Descriptors Relationship of Physicochemical Parameters to Classifications of Odor Based on Similarity Measures Molecular Parameters and Odor Thresholds Conclusions Regarding Physicochemical Parameters and Odor Quality Physiology and Anatomy of Olfaction Basic Anatomy Transduction and Adaptation of Olfactory Signals Molecular Biology Of Olfaction Taste Taste Classification Schemes Based on Sensory Properties Physiology and Anatomy of Taste Transduction of Taste Signals Molecular Biology of Taste Final Comment PY - 2004/1/15/ DO - 10.1002/3527601597.ch1 SP - 1-31 PB - Wiley-VCH Verlag GmbH & Co. KGaA UR - http://dx.doi.org/10.1002/3527601597.ch1 ER - TY - CHAP TI - Loss of Taste, Smell, and Other Senses with Age AU - Schiffman, Susan S. AU - Rogers, Mamie O. AU - Zervakis, Jennifer T2 - Handbook of Clinical Nutrition and Aging AB - There is an increasing awareness of the potential for maintaining functional status and quality of life to very old age. Integral to that aim is retaining the function of the senses, which are vital for learning, interacting, taking pleasure from the outside world, and overall health. All sensory modalities (including taste, smell, vision, hearing, and touch) undergo age-related declines, although the time of onset and degree of loss for a particular sensory modality varies among individuals. Many changes in the senses are not an inevitable consequence of aging, but rather are influenced by such factors as disease, medication use, and environmental factors including nutrition. Current research aims to better understand the mechanisms of age-related sensory losses and to develop methods that compensate for these changes so that the elderly can maximize their remaining abilities. PY - 2004/// DO - 10.1007/978-1-59259-391-0_9 SP - 211-289 PB - Humana Press SN - 9781475753554 9781592593910 UR - http://dx.doi.org/10.1007/978-1-59259-391-0_9 ER - TY - ER - TY - JOUR TI - Odor from Industrial Hog Farming Operations and Mucosal Immune Function in Neighbors AU - Avery, Rachel C. AU - Wing, Steve AU - Marshall, Stephen W. AU - Schiffman, Susan S. T2 - Archives of Environmental Health: An International Journal AB - The authors evaluated whether exposure to malodor from industrial hog farming operations has a psychophysiologically mediated immunosuppressive effect on secretory immunoglobulin A (sIgA) in neighbors. Fifteen adults living within 2.4 km (1.5 mi) of at least one hog farming operation rated odor intensity on a 9-point scale and provided saliva samples twice daily for two weeks. The authors used hierarchical regression to model the association between reported odor and sIgA; study participants were their own controls. The natural log of slgA concentration and secretion rate declined, on average, 0.058 (0.032) and 0.116 (0.103), respectively, for each incremental 1-unit increase in reported odor from 4 to 9, adjusted for time of day, suggesting reduced levels of sIgA in response to moderate or high odor. Findings support the hypothesized immunosuppressive effect of malodor on mucosal immunity and provide preliminary data useful in understanding health effects related to malodor from industrial hog farming operations. DA - 2004/2// PY - 2004/2// DO - 10.3200/aeoh.59.2.101-108 VL - 59 IS - 2 SP - 101-108 J2 - Archives of Environmental Health: An International Journal LA - en OP - SN - 0003-9896 UR - http://dx.doi.org/10.3200/aeoh.59.2.101-108 DB - Crossref ER - TY - JOUR TI - DUST AND ODOR EMISSIONS FROM TUNNEL VENTILATED SWINE BUILDINGS IN NORTH CAROLINA AND COMPARISON OF DIFFERENT ODOR EVALUATION METHODS AU - Bottcher, R. W. AU - Keener, K. M. AU - Munilla, R. D. AU - Williams, C. M. AU - Schiffman, S. S. T2 - Applied Engineering in Agriculture AB - Tunnel ventilation of swine buildings conveys odorous dust and gases out of the production buildings. Measurement of dust and odor levels and other environmental parameters is necessary for characterizing emissions and evaluating control options. During evaluations of odor control systems, measurements of dust and odor levels in building inlet and exhaust air were obtained. Odor and dust levels were consistent with data obtained in other states and Europe. Odor concentrations and emission rates were based on odor measurements from the Duke University Taste and Smell Laboratory at several dilution levels, as well as a calibration curve for odor panelists based on swine manure odor. The computed odor concentration based on measurements over a range of dilutions was greater than the predicted odor concentration based on the calibration curve, for two field visits. This result may be due to odorous dust particles increasing odor persistence above that of vaporous odorants from swine manure. Odor measurements were also obtained using headspace sampling of unaspirated and aspirated cotton swatches. Aspirating the swatches increased odor intensity compared to unaspirated swatches and improved correlation with air sample odor intensities. DA - 2004/// PY - 2004/// DO - 10.13031/2013.16064 VL - 20 IS - 3 SP - 343-347 LA - en OP - SN - 1943-7838 UR - http://dx.doi.org/10.13031/2013.16064 DB - Crossref ER - TY - RPRT TI - Miniature RF components enabled by mesoscale rapid manufacturing. AU - Palmer, James A AU - Jokiel, Bernhard AU - Nordquist, Christopher Daniel AU - Kast, Brian Asa AU - Atwood, Clinton J AU - Wicker, Ryan B AU - Grant, Edward AU - Livingston, Frederick Jerald A3 - Sandia National Lab.(SNL-NM), Albuquerque, NM (United States) DA - 2004/// PY - 2004/// PB - Sandia National Lab.(SNL-NM), Albuquerque, NM (United States) ER - TY - CONF TI - Multi-Parameter Power Minimization of Synthesized Datapaths AU - Davis, W.R. AU - Sule, A.M. AU - Hua, H. T2 - IEEE Computer Society Annual Symposium on VLSI AB - As processing technology continues to evolve, power minimization becomes more complex and crucial. Emerging technologies offer an array of different threshold voltages and gate oxide thicknesses. Along with choices of supply-voltage, parallelism, and pipelining, these options complicate the search for energy-optimal architectures. This paper explores the possibility of using convex optimization to solve the multi-parameter optimization problem and presents a case-study of an 8-bit multiply-accumulate block, which is optimized in 250nm and 70nm technologies. C2 - 2004/2// C3 - IEEE Computer Society Annual Symposium on VLSI CY - Lafayette, LA DA - 2004/2// PY - 2004/2/19/ DO - 10.1109/ISVLSI.2004.1339523 SP - 151–157 ER - TY - CONF TI - MM-wave transceivers using SiGe HBT technology AU - Gaucher, B. AU - Beukema, T. AU - Reynolds, S. AU - Floyd, B. AU - Zwick, T. AU - Pfeiffer, U. AU - Liu, D. AU - Cressler, J. C2 - 2004/// C3 - 2004 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems: Digest of Papers DA - 2004/// SP - 81-84 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-20344405688&partnerID=MN8TOARS ER - TY - CONF TI - Deformation of Solder Joints Under Current Stressing: Experimental Measurement and Numerical Simulation AU - Basaran, C. AU - Ye, H. AU - Hopkins, D.C. T2 - 21st International Congress of Theoretical and Applied Mechanics C2 - 2004/// CY - Warsaw, Poland DA - 2004/// PY - 2004/8/15/ ER - TY - CONF TI - Damage mechanics of microelectronics solder joints under high current densities AU - Ye, Hua AU - Basaran, C. AU - Hopkins, D.C. AU - Frear, D. AU - Lin, Jong-Kai T2 - 2004 54th Electronic Components and Technology Conference AB - The electromigration damage in flip chip solder joints of eutectic Sn/Pb was studied under current stressing. The height of the solder joints was 100 /spl mu/m. The mass accumulation near anode side and void nucleation near cathode were observed during current stressing. Surface marker movement technique is used to measure the atomic flux driven by electromigration and to calculate the product of effective charge number and diffusivity, D/spl times/Z*, of the solder. Subsequent experiments reveal that the presence of thermomigration due to joule heating makes the extraction of the product of effective charge number and diffusivity erroneous when using marker movement technique. Pb Phase growth is observed under different current density and temperature. Higher current density leads to faster grain coarsening. Based on the test results, a grain coarsening equation including the influence of current density is proposed, d/sup n/ - d/sup n//sub 0/ = Kj/sup m/t. The current density exponent m is found to be 3, and phase growth exponent n is found to be 5.5. Within our test temperature range, electric current seems to have greater influences on phase growth of solder joint than temperature or thermomigration caused by the temperature gradient due to joule heating during current stressing. Nano indentation tests suggest that mechanical property, e.g. Young's modulus, degrades in the localized area where void nucleates during current stressing. C2 - 2004/9/28/ C3 - 2004 Proceedings. 54th Electronic Components and Technology Conference (IEEE Cat. No.04CH37546) CY - Las Vegas, NV DA - 2004/9/28/ PY - 2004/6/4/ DO - 10.1109/ectc.2004.1319460 PB - IEEE SN - 0780383656 UR - http://dx.doi.org/10.1109/ectc.2004.1319460 ER - TY - JOUR TI - Pb phase coarsening in eutectic Pb/Sn flip chip solder joints under electric current stressing AU - Ye, Hua AU - Basaran, Cemal AU - Hopkins, Douglas C. T2 - International Journal of Solids and Structures AB - Experimental research on the Pb phase coarsening of eutectic Pb/Sn flip chip solder joint under current stressing is reported. Phase growth is observed under different current densities and temperatures. Higher current density leads to faster grain coarsening. Based on the test results, a grain coarsening equation including the influence of current density is proposed, dn−d0n=Kjmt. The current density exponent m is found to be 3, and phase growth exponent n is 5.5. Within our test temperature range, electric current seems to have a greater influence on Pb phase growth of the solder joint than temperature or thermomigration caused by the temperature gradient due to Joule heating during current stressing. DA - 2004/5// PY - 2004/5// DO - 10.1016/j.ijsolstr.2003.12.001 VL - 41 IS - 9-10 SP - 2743-2755 J2 - International Journal of Solids and Structures LA - en OP - SN - 0020-7683 UR - http://dx.doi.org/10.1016/j.ijsolstr.2003.12.001 DB - Crossref KW - phase coarsening KW - current stressing KW - solder joints KW - electromigration ER - TY - JOUR TI - Deformation of solder joint under current stressing and numerical simulation––II AU - Ye, Hua AU - Basaran, Cemal AU - Hopkins, Douglas C T2 - International Journal of Solids and Structures AB - In this paper, the Moiré interferometry technique is used to measure the in situ displacement evolution of lead-free solder joint under electric current stressing. Large amounts of deformation were observed in the solder joint under high density (above 5000 A/cm2) current stressing. The deformation was found to be due to electromigration in the solder joint and an electromigration constitutive model was applied to simulate the deformation. Both the experimental observations and finite element method (FEM) simulation results indicate that, in addition to the current density level, the current density distribution within the solder joint has a great effect on the displacement development in the solder joint under current stressing. Specifically, greater non-uniformity in current density leads to greater normal deformations within the solder joint in this test module. This is the second part of a series of papers reporting on the deformation of solder joints under current stressing. DA - 2004/9// PY - 2004/9// DO - 10.1016/j.ijsolstr.2004.04.003 VL - 41 IS - 18-19 SP - 4959-4973 J2 - International Journal of Solids and Structures LA - en OP - SN - 0020-7683 UR - http://dx.doi.org/10.1016/j.ijsolstr.2004.04.003 DB - Crossref KW - solder joint KW - electromigration KW - Moire inteferometry KW - modeling ER - TY - JOUR TI - Deformation of solder joint under current stressing and numerical simulation––I AU - Ye, Hua AU - Basaran, Cemal AU - Hopkins, Douglas C. T2 - International Journal of Solids and Structures AB - In this paper, Moiré interferometry technique is used to measure the in situ displacement evolution of lead-free solder joint under electric current stressing. Large deformation was observed in solder joint under high density (104 A/cm2) current stressing. The deformation was found to be due to electromigration in the solder joint. An electromigration constitutive model is applied to simulate deformation of lead-free solder joint under current stressing. The simulation predicts reasonably close displacements results to Moiré interferometry experimental results in both spatial distribution and time history evolution, which indicates that the electromigration model is reasonably good for predicting the mechanical behavior of lead-free solder alloy under electric current stressing. This is the first part of the papers reporting the deformation of solder joint under current stressing. More experimental results are reported in the second paper. DA - 2004/9// PY - 2004/9// DO - 10.1016/j.ijsolstr.2004.04.002 VL - 41 IS - 18-19 SP - 4939-4958 J2 - International Journal of Solids and Structures LA - en OP - SN - 0020-7683 UR - http://dx.doi.org/10.1016/j.ijsolstr.2004.04.002 DB - Crossref KW - electromigration KW - Moire interferometry KW - solder joint KW - modeling ER - TY - JOUR TI - Mechanical Implications of High Current Densities in Flip-chip Solder Joints AU - Ye, Hua AU - Basaran, Cemal AU - Hopkins, Douglas C. T2 - International Journal of Damage Mechanics AB - We studied the electromigration damage to flip-chip solder joints of eutectic Sn/Pb under current stressing at room temperature with a current density of 1.3 × 10 4 A/cm 2 . The height of the solder joints was 100 μm. The mass accumulation near the anode side and the void nucleation near the cathode were observed during current stressing. In the preliminary experiment, the surface marker movement technique was used to measure the atomic flux driven by electromigration and to calculate the product of effective charge number and diffusivity (D × Z * ) of the solder. Subsequent experiments revealed that the presence of thermomigration due to joule heating makes the extraction of the product of effective charge number and diffusivity erroneous when using marker movement technique. DA - 2004/10// PY - 2004/10// DO - 10.1177/1056789504044282 VL - 13 IS - 4 SP - 335-345 J2 - International Journal of Damage Mechanics LA - en OP - SN - 1056-7895 1530-7921 UR - http://dx.doi.org/10.1177/1056789504044282 DB - Crossref KW - solder joint KW - reliability KW - electromigration KW - phase coarsening KW - thermomigration ER - TY - JOUR TI - Failure Modes of Flip Chip Solder Joints Under High Electric Current Density AU - Basaran, C. AU - Ye, H. AU - Hopkins, D. C. AU - Frear, D. AU - Lin, J. K. T2 - Journal of Electronic Packaging AB - The failure modes of flip chip solder joints under high electrical current density are studied experimentally. Three different failure modes are reported. Only one of the failure modes is caused by the combined effect of electromigration and thermomigration, where void nucleation and growth contribute to the ultimate failure of the module. The Ni under bump metallization–solder joint interface is found to be the favorite site for void nucleation and growth. The effect of pre-existing voids on the failure mechanism of a solder joint is also investigated DA - 2004/9/15/ PY - 2004/9/15/ DO - 10.1115/1.1898338 VL - 127 IS - 2 SP - 157-163 LA - en OP - SN - 1043-7398 1528-9044 UR - http://dx.doi.org/10.1115/1.1898338 DB - Crossref KW - flip chip KW - solder joint reliability KW - electromigration KW - thermomigration KW - current stressing KW - high current density KW - power electronics KW - nanoelectronics ER - TY - JOUR TI - CAVA: Hiding L2 misses with checkpoint-assisted value prediction AU - Ceze, Luis AU - Strauss, Karin AU - Tuck, James AU - Renau, Jose AU - Torrellas, Josep T2 - IEEE Computer Architecture Letters DA - 2004/// PY - 2004/// VL - 3 IS - 1 SP - 7-7 ER - TY - CONF TI - Adaptive Information Processing: An Effective Way to Improve Perceptron Branch Predictors AU - Gao, H. AU - Zhou, H. C2 - 2004/12// C3 - 1st Championship Branch Prediction (CBP-1) held with the 37th International Symposium on Microarchitecture (MICRO-37) DA - 2004/12// ER - TY - JOUR TI - Nonequilibrium electrons and phonons in thin film thermionic coolers AU - Vashaee, Daryoosh AU - Shakouri, Ali T2 - Microscale Thermophysical Engineering AB - The effect of hot carriers on the cooling performance of single barrier heterostructure thermionic coolers is studied theoretically. By studying nonequilibrium characteristics of electrons and phonons in the device, fundamental limitation in the cooler performance is analyzed. In particular, we investigated the effect of various boundary conditions at heterojunctions on the electron and phonon temperature distributions. These boundary conditions have a strong impact on the device operation. Thin film devices under high voltage or in high current density are examples of situations where electrons and phonons are not in equilibrium and a coupled transport equation should be solved for an accurate analysis. In a thermoelectric/thermionic device one measures the lattice temperature while cooling occurs in the electron gas. Although at low currents electrons and phonons have the same equilibrium temperature, by increasing the current they may have different temperatures, which can lead to a reduction in cooling power density. We will show that in materials with faster electron energy relaxation, that is, higher electron-phonon coupling, thermionic cooling performance is less affected by high current injection and that recently demonstrated SiGe thin film coolers are not limited by hot carrier effects. DA - 2004/// PY - 2004/// DO - 10.1080/10893950490445225 VL - 8 IS - 2 SP - 91-100 SN - 1089-3954 1091-7640 UR - http://dx.doi.org/10.1080/10893950490445225 KW - thermionic KW - thermoelectric KW - nonequilibrium transport KW - hot carriers KW - thin film coolers ER - TY - JOUR TI - Pekar mechanism of electron-phonon interaction in nanostructures AU - Glavin, B.A. AU - Kochelap, V.A. AU - Linnik, T.L. AU - Kim, K.W. T2 - physica status solidi (c) AB - We propose a new mechanism of electron-acoustic phonon interaction in nanostructures. It is related to appearance of macroscopic electric potential in external electric field under the phonon-strain-induced modulation of dielectric permittivity. For the case of bulk semiconductors this mechanism was introduced by Pekar for materials with very large dielectric permittivity. We show, that for nanostructures it becomes important for ordinary materials as well due to the presence of very strong confining electric fields. It is demonstrated, that in nanostructures not only the absolute value of the electric field, but also its spatial distribution is important. We consider the specific example of Pekar interaction contribution to the electron energy relaxation process in silicon inversion layers, where it leads to the piezoelectric-like dependence of the dissipated power. Finally, we discuss relevance of Pekar interaction to results of recent measurements of electron transport characteristics in silicon nanostructures. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) DA - 2004/11// PY - 2004/11// DO - 10.1002/pssc.200405339 VL - 1 IS - 11 SP - 2779-2782 J2 - phys. stat. sol. (c) LA - en OP - SN - 1610-1634 1610-1642 UR - http://dx.doi.org/10.1002/pssc.200405339 DB - Crossref ER - TY - JOUR TI - Linear boundary extensions for finite length signals and paraunitary two-channel filterbanks AU - Jiménez, M.E.D. AU - Prelcic, N.G. T2 - IEEE Transactions on Signal Processing AB - In this paper, we introduce a novel and general matrix formulation of artificial linear boundary extension methods for removing border effects inherent to any paraunitary two-channel size-limited filterbank. This new characterization of the transformation operator allows us to prove that perfect reconstruction (PR) of finite signals can be ensured under some conditions without using extra subband coefficients; in other words, we characterize the signal extension methods that lead to nonexpansive transforms. The necessary and sufficient condition we find allows us to show that some traditional extension techniques that are being used in an expansive way, such as the polynomial extension, lead in fact to nonexpansive invertible transforms; moreover, we can also prove that in contradiction to previous literature, not every transformation matrix associated with a linear extension is invertible even if using prototype filters of the same length. Apart from these invertibility criteria, we propose the first algorithm for the design of all linear extensions and their associated biorthogonal boundary filters that lead to nonexpansive and invertible transforms. Analogously, we provide the first method for the design of all linear extensions that yield orthogonal transforms: We construct an infinite number of orthogonal extensions, apart from the commonly used periodic extension, and their associated orthogonal boundary filters. The final contribution of the paper is a new algorithm for the design of smooth orthogonal extensions, which keep the orthogonality property and overcome the main drawback of periodization, that is, the introduction of subband coefficients of great amplitude near the boundaries in the transform domain. DA - 2004/// PY - 2004/// DO - 10.1109/TSP.2004.836526 VL - 52 IS - 11 SP - 3213-3226 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-7544241230&partnerID=MN8TOARS KW - border effects KW - boundary extensions KW - orthogonal transforms KW - smooth orthogonal extensions KW - two-channel filterbanks ER - TY - CONF TI - Cross-layer scheduling for power efficiency in wireless sensor networks AB - Wireless sensor networks are considered the sensing technology of the future. Large numbers of untethered sensor nodes can be used for tracking small animals and targets, environmental monitoring, enforcing security perimeters, etc. A major problem for many sensor network applications is determining the most efficient way of conserving the energy of the power source. Some networks use batteries, while others suggest different methods of gathering energy (e.g., solar cells). Regardless of the powering method, energy conservation is of prime importance for sensor networks. The best way to conserve energy is to turn the sensor nodes off; however, since an inactive sensor node is no longer part of the network, the network can become disconnected. This creates a fundamental trade-off. In this paper, we propose a deterministic, schedule-based energy conservation scheme. In the proposed approach, time-synchronized sensors form on-off schedules that enable the sensors to be awake only when necessary. The schedule establishment is fully distributed and thus appropriate for large sensor networks. The performance of the proposed approach is evaluated through the use of simulations C2 - 2004/// C3 - IEEE INFOCOM 2004 DA - 2004/// DO - 10.1109/infcom.2004.1354585 UR - http://dx.doi.org/10.1109/infcom.2004.1354585 ER - TY - CONF TI - Multiuser space-time block coded MIMO system with downlink precoding C2 - 2004/// C3 - IEEE International Conference on Communications DA - 2004/// VL - 5 SP - 2689-2693 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4143114693&partnerID=MN8TOARS ER - TY - JOUR TI - What is the value of limited feedback for MIMO channels? T2 - IEEE Communications Magazine AB - Feedback in a communications system can enable the transmitter to exploit channel conditions and avoid interference. In the case of a multiple-input multiple-output channel, feedback can be used to specify a precoding matrix at the transmitter, which activates the strongest channel modes. In situations where the feedback is severely limited, important issues are how to quantize the information needed at the transmitter and how much improvement in associated performance can be obtained as a function of the amount of feedback available. We give an overview of some recent work in this area. Methods are presented for constructing a set of possible precoding matrices, from which a particular choice can be relayed to the transmitter. Performance results show that even a few bits of feedback can provide performance close to that with full channel knowledge at the transmitter. DA - 2004/// PY - 2004/// DO - 10.1109/MCOM.2004.1341261 VL - 42 IS - 10 SP - 54-59 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-7244221856&partnerID=MN8TOARS ER - TY - JOUR TI - Special issue: Multiple-input multiple-output (MIMO) communications AU - Heath, R.W. AU - Larsson, E.G. AU - Murch, R. AU - Nehorai, A. AU - Uysal, M. T2 - Wireless Communications and Mobile Computing AB - Wireless Communications and Mobile ComputingVolume 4, Issue 7 p. 693-696 EditorialFree Access Special Issue: Multiple-Input Multiple-Output (MIMO) Communications Robert W. Heath, Robert W. Heath Guest Editor University of Texas, USASearch for more papers by this authorErik G. Larsson, Erik G. Larsson Guest Editor University of Florida, USASearch for more papers by this authorRoss Murch, Ross Murch Guest Editor The Hong Kong University of Science and Technology, Hong KongSearch for more papers by this authorArye Nehorai, Arye Nehorai Guest Editor The University of Illinois at Chicago, USASearch for more papers by this authorMurat Uysal, Murat Uysal Guest Editor University of Waterloo, CanadaSearch for more papers by this author Robert W. Heath, Robert W. Heath Guest Editor University of Texas, USASearch for more papers by this authorErik G. Larsson, Erik G. Larsson Guest Editor University of Florida, USASearch for more papers by this authorRoss Murch, Ross Murch Guest Editor The Hong Kong University of Science and Technology, Hong KongSearch for more papers by this authorArye Nehorai, Arye Nehorai Guest Editor The University of Illinois at Chicago, USASearch for more papers by this authorMurat Uysal, Murat Uysal Guest Editor University of Waterloo, CanadaSearch for more papers by this author First published: 09 November 2004 https://doi.org/10.1002/wcm.247Citations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume4, Issue7Special Issue: Special Issue: Multiple-Input Multiple-Output (MIMO) CommunicationsNovember 2004Pages 693-696 ReferencesRelatedInformation DA - 2004/// PY - 2004/// DO - 10.1002/wcm.247 VL - 4 IS - 7 SP - 593-696 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-13244267097&partnerID=MN8TOARS ER - TY - CONF TI - Rapid MIMO-OFDM software defined radio system prototyping C2 - 2004/// C3 - IEEE Workshop on Signal Processing Systems, SiPS: Design and Implementation DA - 2004/// SP - 182-187 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-17044378192&partnerID=MN8TOARS ER - TY - CONF TI - Transmit selection diversity for multiuser spatial multiplexing systems C2 - 2004/// C3 - GLOBECOM - IEEE Global Telecommunications Conference DA - 2004/// VL - 4 SP - 2625-2629 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-18144397203&partnerID=MN8TOARS ER - TY - CONF TI - Practical costa precoding for the multiple antenna broadcast channel C2 - 2004/// C3 - GLOBECOM - IEEE Global Telecommunications Conference DA - 2004/// VL - 6 SP - 3942-3946 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-18144372344&partnerID=MN8TOARS ER - TY - CONF TI - Optimal CDMA signatures: A finite-step approach C2 - 2004/// C3 - IEEE International Symposium on Spread Spectrum Techniques and Applications DA - 2004/// SP - 335-339 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-26944485134&partnerID=MN8TOARS ER - TY - CONF TI - Multi-user diversity for the multiple antenna broadcast channel with linear receivers: Asymptotic analysis C2 - 2004/// C3 - Conference Record - Asilomar Conference on Signals, Systems and Computers DA - 2004/// VL - 1 SP - 886-890 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-21644458808&partnerID=MN8TOARS ER - TY - CONF TI - Multi-mode precoding using linear receivers for limited feedback MIMO systems C2 - 2004/// C3 - IEEE International Conference on Communications DA - 2004/// VL - 1 SP - 448-452 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4143110330&partnerID=MN8TOARS ER - TY - CONF TI - Interpolation based transmit beamforming for MIMO-OFDM with limited feedback C2 - 2004/// C3 - IEEE International Conference on Communications DA - 2004/// VL - 1 SP - 249-253 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4143145417&partnerID=MN8TOARS ER - TY - CONF TI - Limited feedback power loading for OFDM C2 - 2004/// C3 - Proceedings - IEEE Military Communications Conference MILCOM DA - 2004/// VL - 1 SP - 71-77 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-27744510283&partnerID=MN8TOARS ER - TY - CONF TI - Interpolation based unitary precoding for spatial multiplexing MIMO-OFDM with limited feedback C2 - 2004/// C3 - GLOBECOM - IEEE Global Telecommunications Conference DA - 2004/// VL - 1 SP - 214-218 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-18144408720&partnerID=MN8TOARS ER - TY - CONF TI - Impact of antenna geometry on MIMO communication in indoor clustered channels C2 - 2004/// C3 - IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) DA - 2004/// VL - 2 SP - 1700-1703 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4544277232&partnerID=MN8TOARS ER - TY - CONF TI - Limited feedback precoding for orthogonal space-time block codes C2 - 2004/// C3 - GLOBECOM - IEEE Global Telecommunications Conference DA - 2004/// VL - 1 SP - 561-565 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-18144429497&partnerID=MN8TOARS ER - TY - CONF TI - Joint frequency offset estimation and interference cancellation for MIMO-OFDM systems C2 - 2004/// C3 - IEEE Vehicular Technology Conference DA - 2004/// VL - 60 SP - 1553-1557 M1 - 3 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-17144392892&partnerID=MN8TOARS ER - TY - CONF TI - Improving throughput and fairness for MIMO ad hoc networks using antenna selection diversity C2 - 2004/// C3 - GLOBECOM - IEEE Global Telecommunications Conference DA - 2004/// VL - 5 SP - 3363-3367 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-18144426381&partnerID=MN8TOARS ER - TY - CONF TI - Grassmannian beamforming on correlated MIMO channels C2 - 2004/// C3 - GLOBECOM - IEEE Global Telecommunications Conference DA - 2004/// VL - 1 SP - 106-110 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-18144375936&partnerID=MN8TOARS ER - TY - CONF TI - Long range channel prediction for adaptive OFDM systems AU - Wong, I.C. AU - Forenza, A. AU - Heath, R.W. AU - Evans, B.L. C2 - 2004/// C3 - Conference Record - Asilomar Conference on Signals, Systems and Computers DA - 2004/// VL - 1 SP - 732-736 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-21644486341&partnerID=MN8TOARS ER - TY - JOUR TI - Finite-step algorithms for constructing optimal CDMA signature sequences T2 - IEEE Transactions on Information Theory AB - A description of optimal sequences for direct-spread code-division multiple access (DS-CDMA) is a byproduct of recent characterizations of the sum capacity. This paper restates the sequence design problem as an inverse singular value problem and shows that the problem can be solved with finite-step algorithms from matrix theory. It proposes a new one-sided algorithm that is numerically stable and faster than previous methods. DA - 2004/// PY - 2004/// DO - 10.1109/TIT.2004.836698 VL - 50 IS - 11 SP - 2916-2921 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-8144223740&partnerID=MN8TOARS KW - algorithms KW - code-division multiple access (CDMA) KW - inverse eigenvalue problems KW - optimal sequences KW - sum capacity ER - TY - JOUR TI - Diversity performance of precoded orthogonal space-time block codes using limited feedback T2 - IEEE Communications Letters AB - Orthogonal space-time block codes (OSTBCs) are simple space-time codes that can be used for open-loop transmit diversity systems. OSTBCs, however, can only be designed for certain numbers of transmit antennas. Channel-dependent linear precoders have been proposed to overcome this deficiency, but it is not clear what conditions the precoder design must satisfy to guarantee full diversity order. In this letter, we show necessary and sufficient conditions for linear precoded OSTBCs to provide full diversity order. We show that limited feedback precoding can achieve full diversity order using fewer bits than limited feedback beamforming. We also present a simplified version of antenna subset selection for OSTBCs that can provide full diversity order with low complexity and only a small amount of feedback. DA - 2004/// PY - 2004/// DO - 10.1109/LCOMM.2004.827381 VL - 8 IS - 5 SP - 305-307 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-2942536692&partnerID=MN8TOARS KW - antenna selection KW - diversity methods KW - feedback KW - MIMO systems KW - space-time coding ER - TY - CONF TI - Construction of equiangular signatures for synchronous CDMA systems C2 - 2004/// C3 - IEEE International Symposium on Spread Spectrum Techniques and Applications DA - 2004/// SP - 708-712 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-26944493737&partnerID=MN8TOARS ER - TY - CONF TI - Comparison of space-time water-filling and spatial water-filling for MIMO fading channels C2 - 2004/// C3 - GLOBECOM - IEEE Global Telecommunications Conference DA - 2004/// VL - 1 SP - 431-435 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-18144376745&partnerID=MN8TOARS ER - TY - CONF TI - Chase decoding for space-time codes C2 - 2004/// C3 - IEEE Vehicular Technology Conference DA - 2004/// VL - 60 SP - 1663-1667 M1 - 3 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-17144430439&partnerID=MN8TOARS ER - TY - CONF TI - An upper bound on SNR for limited feedback MIMO beamforming systems C2 - 2004/// C3 - 2004 IEEE Information Theory Workshop - Proceedings, ITW DA - 2004/// SP - 408-412 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-19544380000&partnerID=MN8TOARS ER - TY - CONF TI - Adaptive feedback for MIMO beamforming systems C2 - 2004/// C3 - IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC DA - 2004/// SP - 213-217 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-21644470893&partnerID=MN8TOARS ER - TY - CONF TI - A lower bound on outage probability of limited feedback MIMO beamforming systems C2 - 2004/// C3 - Conference Record - Asilomar Conference on Signals, Systems and Computers DA - 2004/// VL - 1 SP - 876-880 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-21644441092&partnerID=MN8TOARS ER - TY - CONF TI - A low complexity algorithm to simulate the spatial covariance matrix for clustered MIMO channel models C2 - 2004/// C3 - IEEE Vehicular Technology Conference DA - 2004/// VL - 59 SP - 889-893 M1 - 2 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-15544385927&partnerID=MN8TOARS ER - TY - CONF TI - A space-time FIR equalizer training algorithm for MIMO-OFDM systems C2 - 2004/// C3 - 2004 International Conference on Signal Processing and Communications, SPCOM DA - 2004/// SP - 550-554 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-28244490587&partnerID=MN8TOARS ER - TY - CONF TI - A joint source-channel distortion model for JPEG compressed images AU - Sabir, M.F. AU - Sheikh, H.R. AU - Heath, R.W. AU - Bovik, A.C. C2 - 2004/// C3 - Proceedings - International Conference on Image Processing, ICIP DA - 2004/// VL - 2 SP - 3249-3252 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-20444476685&partnerID=MN8TOARS ER - TY - JOUR TI - Deformation potentials of the E1(TO) and E2 modes of InN AU - Darakchieva, V. AU - Paskov, P. P. AU - Valcheva, E. AU - Paskova, T. AU - Monemar, B. AU - Schubert, M. AU - Lu, H. AU - Schaff, W. J. T2 - Applied Physics Letters AB - The deformation potentials of the E1(TO) and E2 modes of InN are determined by combining infrared spectroscopic ellipsometry, Raman scattering, and x-ray diffraction measurements, and using a reported value of the mode Grüneisen parameter. The deformation potentials are obtained for two sets of stiffness constants. Strain-free values of the InN E1(TO) mode of 477.9 cm−1 and of the E2 mode of 491.1 cm−1 have been determined. DA - 2004/5/3/ PY - 2004/5/3/ DO - 10.1063/1.1738520 VL - 84 IS - 18 SP - 3636-3638 J2 - Appl. Phys. Lett. LA - en OP - SN - 0003-6951 1077-3118 UR - http://dx.doi.org/10.1063/1.1738520 DB - Crossref ER - TY - JOUR TI - Infrared ellipsometry and Raman studies of hexagonal InN films: correlation between strain and vibrational properties AU - Darakchieva, V. AU - Paskov, P.P. AU - Valcheva, E. AU - Paskova, T. AU - Schubert, M. AU - Bundesmann, C. AU - Lu, H. AU - Schaff, W.J. AU - Monemar, B. T2 - Superlattices and Microstructures AB - The vibrational properties of InN films with different strain have been studied using Infrared ellipsometry and Raman scattering spectroscopy. We have established a correlation between the phonon mode parameters and the strain, which allows the determination of the deformation potentials and the strain-free frequencies of the InN E1(TO) and E2 modes. The LO phonons and their coupling to the free-carrier plasmon excitations are also discussed in relation to the carrier concentration in the films. DA - 2004/10// PY - 2004/10// DO - 10.1016/j.spmi.2004.09.014 VL - 36 IS - 4-6 SP - 573-580 J2 - Superlattices and Microstructures LA - en OP - SN - 0749-6036 UR - http://dx.doi.org/10.1016/j.spmi.2004.09.014 DB - Crossref ER - TY - JOUR TI - Free-to-bound radiative recombination in highly conducting InN epitaxial layers AU - Arnaudov, B. AU - Paskova, T. AU - Paskov, P.P. AU - Magnusson, B. AU - Valcheva, E. AU - Monemar, B. AU - Lu, H. AU - Schaff, W.J. AU - Amano, H. AU - Akasaki, I. T2 - Superlattices and Microstructures AB - We present a theoretical simulation of near-band-edge emission spectra of highly conducting n-InN assuming the model of ‘free-to-bound’ radiative recombination (FBRR) of degenerate electrons from the conduction band with nonequilibrium holes located in the valence band tails. We also study experimental photoluminescence (PL) spectra of highly conducting InN epitaxial layers grown by MBE and MOVPE with electron concentrations in the range (7.7×1017–6×1018) cm−3 and find that the energy positions and shape of the spectra depend on the impurity concentration. By modeling the experimental PL spectra of the InN layers we show that spectra can be nicely interpreted in the framework of the FBRR model with specific peculiarities for different doping levels. Analyzing simultaneously the shape and energy position of the InN emission spectra we determine the fundamental bandgap energy of InN to vary between Eg=692 meV for effective mass mn0=0.042m0 and Eg=710 meV for mn0=0.1m0. DA - 2004/10// PY - 2004/10// DO - 10.1016/j.spmi.2004.09.013 VL - 36 IS - 4-6 SP - 563-571 J2 - Superlattices and Microstructures LA - en OP - SN - 0749-6036 UR - http://dx.doi.org/10.1016/j.spmi.2004.09.013 DB - Crossref ER - TY - JOUR TI - Characterization of mass-transport grown GaN by hydride vapour-phase epitaxy AU - Paskova, T. AU - Paskov, P.P. AU - Goldys, E.M. AU - Valcheva, E. AU - Darakchieva, V. AU - Södervall, U. AU - Godlewski, M. AU - Zielinski, M. AU - Hautakangas, S. AU - Saarinen, K. AU - Carlström, C.F. AU - Wahab, Q. AU - Monemar, B. T2 - Journal of Crystal Growth AB - A comprehensive study of the morphological, optical and microstructural properties of mass-transport (MT) and conventionally grown GaN by hydride vapour-phase epitaxy is presented. Spatially resolved techniques have been utilized to reveal in a comparative way, the characteristics of the material grown either in predominant vertical or lateral growth modes. A strong donor–acceptor pair (DAP) emission is observed from the MT regions with a distinctive intensity contrast between the exciton and DAP emission bands from MT and nontransport regions. Secondary ion mass spectroscopy and imaging were employed to investigate the impurity incorporation into different regions. An increase of residual oxygen and aluminium impurity concentrations was found in the MT areas. In addition, positron annihilation spectroscopy showed a strong signal of Ga vacancy clusters in the MT grown material. The increase of the point defect concentrations of both Ga vacancy and oxygen impurity, most likely forming defect complexes, is related to the enhancement of the DAP emission. DA - 2004/12// PY - 2004/12// DO - 10.1016/j.jcrysgro.2004.09.025 VL - 273 IS - 1-2 SP - 118-128 J2 - Journal of Crystal Growth LA - en OP - SN - 0022-0248 UR - http://dx.doi.org/10.1016/j.jcrysgro.2004.09.025 DB - Crossref KW - emission properties KW - impurities KW - stresses KW - volume defects KW - mass transport KW - nitrides ER - TY - JOUR TI - HVPE-GaN: comparison of emission properties and microstructure of films grown on different laterally overgrown templates AU - Paskova, T. AU - Valcheva, E. AU - Paskov, P.P. AU - Monemar, B. AU - Roskowski, A.M. AU - Davis, R.F. AU - Beaumont, B. AU - Gibart, P. T2 - Diamond and Related Materials AB - We report on a comparative study of defect and emission distributions in thick hydride vapor phase epitaxial (HVPE) GaN films grown on two different patterned template structures separately produced by multi-step procedures using metalorganic vapor phase epitaxy (MOVPE). The observed differences in the microstructures and emission distributions at the early stages of the growth in both cases were related to the change of the dominating growth mode sequence and point defects incorporation. Both template structures were found to favor formation of voids in the coalescence regions, which leads to a partial strain relaxation and allows overgrowth of thicker films without cracks. DA - 2004/4// PY - 2004/4// DO - 10.1016/j.diamond.2003.10.072 VL - 13 IS - 4-8 SP - 1125-1129 J2 - Diamond and Related Materials LA - en OP - SN - 0925-9635 UR - http://dx.doi.org/10.1016/j.diamond.2003.10.072 DB - Crossref KW - GaN quasi-substrates KW - microstructure KW - emission distribution KW - TEM KW - CL ER - TY - JOUR TI - Hydride vapor-phase epitaxial GaN thick films for quasi-substrate applications: Strain distribution and wafer bending AU - Paskova, T. AU - Darakchieva, V. AU - Valcheva, E. AU - Paskov, P. P. AU - Ivanov, I. G. AU - Monemar, B. AU - Böttcher, T. AU - Roder, C. AU - Hommel, D. T2 - Journal of Electronic Materials DA - 2004/5// PY - 2004/5// DO - 10.1007/S11664-004-0189-4 VL - 33 IS - 5 SP - 389-394 J2 - Journal of Elec Materi LA - en OP - SN - 0361-5235 1543-186X UR - http://dx.doi.org/10.1007/S11664-004-0189-4 DB - Crossref KW - GaN KW - HVPE KW - strain KW - wafer bending ER - TY - JOUR TI - Band structure effects in nitrogen K-edge resonant inelastic X-ray scattering from GaN AU - Strocov, V. N. AU - Schmitt, T. AU - Rubensson, J.-E. AU - Blaha, P. AU - Paskova, T. AU - Nilsson, P. O. T2 - physica status solidi (b) AB - Abstract Systematic experimental data on resonant inelastic X‐ray scattering (RIXS) in GaN near the N K‐edge are presented for the first time. Excitation energy dependence of the spectral structures manifests the band structure effects originating from momentum selectivity of the RIXS process. This finding allows obtaining k ‐resolved band structure information for GaN crystals and nanostructures. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) DA - 2004/6// PY - 2004/6// DO - 10.1002/pssb.200409040 VL - 241 IS - 7 SP - R27-R29 J2 - phys. stat. sol. (b) LA - en OP - SN - 0370-1972 1521-3951 UR - http://dx.doi.org/10.1002/pssb.200409040 DB - Crossref ER - TY - JOUR TI - Optical investigation of AlGaN/GaN quantum wells and superlattices AU - Monemar, B. AU - Paskov, P. P. AU - Haradizadeh, H. AU - Bergman, J. P. AU - Valcheva, E. AU - Darakchieva, V. AU - Arnaudov, B. AU - Paskova, T. AU - Holtz, P. O. AU - Pozina, G. AU - Kamiyama, S. AU - Iwaya, M. AU - Amano, H. AU - Akasaki, I. T2 - physica status solidi (a) AB - We report a detailed optical study of several sets of multiple quantum wells (MQWs) in the AlGaN/GaN system, as well as AlN/GaN superlattice (SL) structures. In this study all materials were grown by MOCVD, as opposed to most previous studies where MBE was employed. In undoped MQWs discrete photoluminescence (PL) peaks related to discrete well width fluctuations by one full c lattice parameter are clearly observed. In doped samples this effect appears to be screened. While the recombination process in undoped samples is excitonic, in MQWs doped with Si above about 5 × 1018 cm–3 free electrons (a 2DEG) are dominant, and the PL process is a free electrons-localized hole transition at low temperatures. The hole localization prevails up to very high n-doping, as was previously observed in bulk GaN. The hole localization is demonstrated via several experiments, including results on PL transient decay times and LO phonon coupling. Near surface band bending, due mainly to dopant depletion in doped structures or interaction with surface states in case of higher Al content in barriers, influences the distribution of electron filling among the QWs, making a detailed modeling of the spectral shape somewhat ambiguous. It is found that AlN barriers promote a strong room temperature PL signal from the QWs, as opposed to the case with AlGaN barriers. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) DA - 2004/8// PY - 2004/8// DO - 10.1002/pssa.200404849 VL - 201 IS - 10 SP - 2251-2258 J2 - phys. stat. sol. (a) LA - en OP - SN - 0031-8965 1521-396X UR - http://dx.doi.org/10.1002/pssa.200404849 DB - Crossref ER - TY - JOUR TI - Polar and nonpolar GaN grown by HVPE: Preferable substrates for nitride-based emitting devices AU - Paskova, T. AU - Paskov, P. P. AU - Valcheva, E. AU - Darakchieva, V. AU - Birch, J. AU - Kasic, A. AU - Arnaudov, B. AU - Tungasmita, S. AU - Monemar, B. T2 - physica status solidi (a) AB - We report on hydride vapor phase epitaxial growth of thick nonpolar GaN films on r-plane sapphire in comparison with polar GaN films on c-plane sapphire substrates with AlN buffer layers, aiming at developing of their quasi-substrate application. Both the thick films and the buffers were identified to have single crystalline structures. The microstructure of the films was studied by transmission electron microscopy. High resolution X-ray diffraction mapping and photoluminescence measurements were employed to characterize the strain present in both polar and nonpolar GaN films. In contrast to c-plane GaN, which is always characterised by isotropic in-plane properties, the a-plane GaN shows a strong in-plane anisotropy of the growth rate, morphology and strain distribution. Different defect, impurity and free carrier concentrations were observed in the polar and nonpolar material. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) DA - 2004/8// PY - 2004/8// DO - 10.1002/pssa.200404818 VL - 201 IS - 10 SP - 2265-2270 J2 - phys. stat. sol. (a) LA - en OP - SN - 0031-8965 1521-396X UR - http://dx.doi.org/10.1002/pssa.200404818 DB - Crossref ER - TY - JOUR TI - Polarized photoluminescence of exciton-polaritons in free-standing GaN AU - Paskov, P. P. AU - Paskova, T. AU - Holtz, P. O. AU - Monemar, B. T2 - physica status solidi (a) AB - We report on the polarization properties of the exciton–polariton modes in GaN. The dispersion curves and the expected emission lineshape of polaritons for all polarization configurations are calculated taking into account the spatial dispersion and the simultaneous exciton–photon coupling of all optically active states. An experimental study of the exciton–polariton luminescence in a free-standing GaN layer is also performed. The spectra reveal a clear difference between the emissions polarized perpendicular and parallel to the c-axis of the crystal. The experimental results are discussed in terms of optical selection rules and population of the polariton states. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) DA - 2004/3// PY - 2004/3// DO - 10.1002/pssa.200304093 VL - 201 IS - 4 SP - 678-685 J2 - phys. stat. sol. (a) LA - en OP - SN - 0031-8965 1521-396X UR - http://dx.doi.org/10.1002/pssa.200304093 DB - Crossref ER - TY - JOUR TI - Mesoscale Three Dimensional Lattices Formed in Polymer Dispersed Liquid Crystals: A Diamond-Like Face Centered Cubic AU - Escuti, Michael AU - Crawford, Gregory T2 - Molecular Crystals and Liquid Crystals AB - Abstract Mesoscale three-dimensional lattices are formed in polymer-dispersed liquid crystals using one-step holographic fabrication. Nematic liquid crystal domains are patterned within a rigid polymer binder through an irradiance-driven diffusion and phase-separation process, forming a low index-contrast photonic crystals whose dielectric profile mimics the irradiance profile applied during formation. Electric fields are used to align the liquid crystal domains, allowing electrical control of the coherent scattering from these lattices. Here we present a diamond-like face centered-cubic-lattice(fcc), highlighting the several advantages over the simple fcc counterpart, including easier processing, operation in the near infrared, and deeper stopbands. Keywords: Diamond-like Face-centered-cubicHolographyH-PDLCMesoscale LatticesPhotonic Crystals DA - 2004/1// PY - 2004/1// DO - 10.1080/15421400490501158 VL - 421 IS - 1 SP - 23-36 J2 - Molecular Crystals and Liquid Crystals LA - en OP - SN - 1542-1406 1563-5287 UR - http://dx.doi.org/10.1080/15421400490501158 DB - Crossref KW - diamond-like face-centered-cubic KW - holography KW - H-PDLC KW - mesoscale lattices KW - photonic crystals ER - TY - JOUR TI - Optical-strain characteristics of anisotropic polymer films fabricated from a liquid crystal diacrylate AU - Escuti, Michael J. AU - Cairns, Darran R. AU - Crawford, Gregory P. T2 - Journal of Applied Physics AB - The optomechanical characteristics of oriented polymer films made from a photopolymerizable liquid crystal diacrylate (BASF LC242) were examined, with general implications for oriented films of similar materials being used and considered for display-component applications. The birefringence of these uniaxial films before and after polymerization was determined by measuring the retardation between crossed polarizers, (resulting in Δn=0.142±0.002 at 633 nm for the cured polymer films). Optical-strain characteristics were also determined by measuring the transmittance of the films between crossed polarizers at two wavelengths (612 and 633 nm) during the application of a monotonically increasing tensile strain. Under the conservative assumption that Poisson’s ratio is constant for the relatively small strains in our experiment, we develop a strained-waveplate model to detect changes in birefringence directly from the modulation in transmittance with increasing strain. We show that strain applied along the axis of the polymer chains did not substantially affect the birefringence, and strain applied perpendicularly caused only a slight decrease (∼1% decrease for 10% strain). These results highlight the robustness of fully polymerized reactive mesogen optical films to withstand the moderate strains anticipated during manufacturing processes and in-service deformation caused by bending or impact. DA - 2004/3// PY - 2004/3// DO - 10.1063/1.1643192 VL - 95 IS - 5 SP - 2386-2390 J2 - Journal of Applied Physics LA - en OP - SN - 0021-8979 1089-7550 UR - http://dx.doi.org/10.1063/1.1643192 DB - Crossref ER - TY - CONF TI - Operating characteristics of the convertible static compensator on the 345 kV network AU - Sun, J. AU - Hopkins, L. AU - Shperling, B. AU - Fardanesh, B. AU - Graham, M.R. AU - Parisi, M. AU - MacDonald, S. AU - Bhattacharya, S. AU - Berkowitz, S. AU - Edris, A. C2 - 2004/// C3 - 2004 IEEE PES Power Systems Conference and Exposition DA - 2004/// VL - 2 SP - 732-737 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-20144388605&partnerID=MN8TOARS ER - TY - JOUR TI - High-efficiency metamorphic GaInP/GaInAs/Ge solar cells grown by MOVPE AU - Fetzer, C.M. AU - King, R.R. AU - Colter, P.C. AU - Edmondson, K.M. AU - Law, D.C. AU - Stavrides, A.P. AU - Yoon, H. AU - Ermer, J.H. AU - Romero, M.J. AU - Karam, N.H. T2 - Journal of Crystal Growth AB - This paper focuses on the metal-organic vapor-phase epitaxy growth of 3-junction (3J) solar cells where the epitaxial Ga0.44In0.56P top and Ga0.92In0.08As middle subcells are grown lattice-mismatched on a Ge substrate. Single-junction metamorphic devices with 8% and 12%-In, GaInAs are grown on 100 mm dia. (0 0 1) Ge substrates and evaluated in comparison to approximately lattice-matched GaAs and Ga0.99In0.01As subcells. Layers are observed to be nearly 100% relaxed by high-resolution X-ray diffraction. Threading dislocation densities of ∼2×105 cm−2 in the 8%-In layers are observed by electron beam induced current and cathodoluminescence. Single-junction devices show a constant offset between open-circuit voltage and bandgap of ∼380 mV. Building upon these results, 3J metamorphic Ga0.44In0.56P/Ga0.92In0.08As/Ge solar cells are fabricated. Very high performances of small area devices are reported with 28.8% efficiency under the AM0 spectrum and 31.3% efficiency under the AM1.5G 1-sun terrestrial spectrum. DA - 2004/1// PY - 2004/1// DO - 10.1016/j.jcrysgro.2003.11.026 VL - 261 IS - 2-3 SP - 341-348 J2 - Journal of Crystal Growth LA - en OP - SN - 0022-0248 UR - http://dx.doi.org/10.1016/j.jcrysgro.2003.11.026 DB - Crossref KW - metamorphic KW - metalorganic vapor phase epitaxy KW - GaInAs KW - GaInP KW - germanium KW - solar cells ER - TY - CONF TI - Validation of Adaptive Transmission for Realistic Single- and Multi-Carrier Mobile Radio Channels AU - Yang, T. S. AU - Duel-Hallen, A. AU - Hallen, H. C2 - 2004/// C3 - Proceedings of URSI'04, Special Session on Propagation Effects in Wireless Communications Channels CY - Boulder, CO DA - 2004/// SP - 75 N1 - – An invited paper RN - – An invited paper ER - TY - CONF TI - Enabling adaptive OFDM for mobile radio channels AU - Yang, Tung-Sheng AU - Duel-Hallen, A. AU - Hallen, H. C2 - 2004/// C3 - MILCOM 2004. 2004 IEEE Military Communications Conference (IEEE Cat. No. 04CH37621) CY - Piscataway, NJ, USA DA - 2004/// VL - Vol. 2 SP - 704 - 10 ER - TY - CONF TI - Nonlinear multiuser precoding for downlink DS-CDMA systems over multipath fading channels AU - Liu, Jia AU - Duel-Hallen, A. C2 - 2004/// C3 - GLOBECOM '04. IEEE Global Telecommunications Conference (IEEE Cat. No.04CH37615) CY - Piscataway, NJ, USA DA - 2004/// VL - vol.1 SP - 277 - 81 ER - TY - JOUR TI - Network decomposition in the many-sources regime AU - Eun, Do Young AU - Shroff, Ness B. T2 - Advances in Applied Probability AB - We derive results that show the impact of aggregation in a queueing network. Our model consists of a two-stage queueing system where the first (upstream) queue serves many flows, of which a certain subset arrive at the second (downstream) queue. The downstream queue experiences arbitrary interfering traffic. In this setup, we prove that, as the number of flows being aggregated in the upstream queue increases, the overflow probability of the downstream queue converges uniformly in the buffer level to the overflow probability of a single queueing system obtained by simply removing the upstream queue in the original two-stage queueing system. We also provide the speed of convergence and show that it is at least exponentially fast. We then extend our results to non-i.i.d. traffic arrivals. DA - 2004/9// PY - 2004/9// DO - 10.1017/S0001867800013173 VL - 36 IS - 03 SP - 893-918 J2 - Adv. Appl. Probab. LA - en OP - SN - 0001-8678 1475-6064 UR - http://dx.doi.org/10.1017/S0001867800013173 DB - Crossref ER - TY - JOUR TI - Downlink Capacity of Interference-Limited MIMO Systems With Joint Detection AU - Dai, H. AU - Molisch, A.F. AU - Poor, H.V. T2 - IEEE Transactions on Wireless Communications AB - The capacity of downlink cellular multiple-input multiple-output (MIMO) systems, where co-channel interference is the dominant channel impairment, is investigated in this paper, mainly from a signal-processing perspective. Turbo space-time multiuser detection (ST MUD) is employed for intracell communications and is shown to closely approach the ultimate capacity limits in Gaussian ambient noise for an isolated cell. Then, it is combined with various multiuser detection methods for combating intercell interference. Among various multiuser detection techniques examined, linear minimum-mean-square-error (MMSE) MUD and successive interference cancellation are shown to be feasible and effective. Based on these two multiuser detection schemes, one of which may outperform the other for different settings, an adaptive detection scheme is developed, which together with a Turbo ST MUD structure offers substantial performance gain over the well-known V-BLAST techniques with coding in this interference-limited cellular environment. The obtained multiuser capacity is excellent in the high to medium signal-to-interference ratio scenario. Nonetheless, numerical results also indicate that a further increase in system complexity, using base-station cooperation, could lead to further significant increases of the system capacity. The asymptotic multicell MIMO capacity with linear MMSE MUD preprocessing is also derived, and this analysis agrees well with the simulation results. DA - 2004/3// PY - 2004/3// DO - 10.1109/twc.2003.821168 VL - 3 IS - 2 SP - 442-453 J2 - IEEE Trans. Wireless Commun. LA - en OP - SN - 1536-1276 UR - http://dx.doi.org/10.1109/twc.2003.821168 DB - Crossref KW - adaptive detection KW - BLAST KW - co-channel interference KW - multiple-input multiple-output (MIMO) systems KW - multiuser detection KW - turbo processing ER - TY - JOUR TI - CDMA Downlink Transmission with Transmit Antenna Arrays and Power Control in Multipath Fading Channels AU - Dai, Huaiyu AU - Mailaender, Laurence AU - Poor, HVincent T2 - EURASIP Journal on Wireless Communications and Networking AB - Wireless code-division multiple-access (CDMA) cellular downlink communications with transmit antenna arrays in multipath fading channels is studied. Various array signal processing techniques at the transmit end are investigated and compared under various settings, in conjunction with power control. No instant downlink channel information is assumed; however, the obtained results are also compared with results assuming ideal feedback. The study is carried out for both circuit-switched and packet-switched systems, where different goals are pursued and different conclusions are drawn. In particular, it is found that the traffic type impacts the algorithm choice in downlink transmission, and that there is no need to seek optimum power control/allocation schemes, which are either too complex or infeasible in practice. Another interesting conclusion is that, even though feedback does not help much for packet-switched systems, it does help for circuit-switched systems, the gain of which increases with the number of antennas. DA - 2004/// PY - 2004/// DO - 10.1155/s1687147204404034 VL - 2004 IS - 1 SP - 219825 J2 - EURASIP J Wirel Commun Netw LA - en OP - SN - 1687-1499 UR - http://dx.doi.org/10.1155/s1687147204404034 DB - Crossref ER - TY - JOUR TI - Cochannel Interference Mitigation and Cooperative Processing in Downlink Multicell Multiuser MIMO Networks AU - Zhang, Hongyuan AU - Dai, Huaiyu T2 - EURASIP Journal on Wireless Communications and Networking AB - Recently, the remarkable capacity potential of multiple-input multiple-output (MIMO) wireless communication systems was unveiled. The predicted enormous capacity gain of MIMO is nonetheless significantly limited by cochannel interference (CCI) in realistic cellular environments. The previously proposed advanced receiver technique improves the system performance at the cost of increased receiver complexity, and the achieved system capacity is still significantly away from the interference-free capacity upper bound, especially in environments with strong CCI. In this paper, base station cooperative processing is explored to address the CCI mitigation problem in downlink multicell multiuser MIMO networks, and is shown to dramatically increase the capacity with strong CCI. Both information-theoretic dirty paper coding approach and several more practical joint transmission schemes are studied with pooled and practical per-base power constraints, respectively. Besides the CCI mitigation potential, other advantages of cooperative processing including the power gain, channel rank/conditioning advantage, and macrodiversity protection are also addressed. The potential of our proposed joint transmission schemes is verified with both heuristic and realistic cellular MIMO settings. DA - 2004/// PY - 2004/// DO - 10.1155/s1687147204406148 VL - 2004 IS - 2 SP - 202654 J2 - EURASIP J Wirel Commun Netw LA - en OP - SN - 1687-1499 UR - http://dx.doi.org/10.1155/s1687147204406148 DB - Crossref ER - TY - JOUR TI - Safety assessment of near infrared light emitting diodes for diffuse optical measurements AU - Bozkurt, Alper AU - Onaral, Banu T2 - BioMedical Engineering OnLine AB - Near infrared (NIR) light has been used widely to monitor important hemodynamic parameters in tissue non-invasively. Pulse oximetry, near infrared spectroscopy, and diffuse optical tomography are examples of such NIR light-based applications. These and other similar applications employ either lasers or light emitting diodes (LED) as the source of the NIR light. Although the hazards of laser sources have been addressed in regulations, the risk of LED sources in such applications is still unknown.Temperature increase of the human skin caused by near infrared LED has been measured by means of in-vivo and in-vitro experiments. Effects of the conducted and radiated heat in the temperature increase have been analyzed separately.Elevations in skin temperature up to 10 degrees C have been observed. The effect of radiated heat due to NIR absorption is low--less than 0.5 degrees C--since emitted light power is comparable to the NIR part of sunlight. The conducted heat due to semiconductor junction of the LED can cause temperature increases up to 9 degrees C. It has been shown that adjusting operational parameters by amplitude modulating or time multiplexing the LED decreases the temperature increase of the skin significantly.In this study, we demonstrate that the major risk source of the LED in direct contact with skin is the conducted heat of the LED semiconductor junction, which may cause serious skin burns. Adjusting operational parameters by amplitude modulating or time multiplexing the LED can keep the LED within safe temperature ranges. DA - 2004/3/22/ PY - 2004/3/22/ DO - 10.1186/1475-925x-3-9 VL - 3 IS - 9 SN - 1475-925X UR - http://dx.doi.org/10.1186/1475-925x-3-9 ER - TY - JOUR TI - Electronic and thermoelectric transport in semiconductor and metallic superlattices AU - Vashaee, Daryoosh AU - Shakouri, Ali T2 - Journal of Applied Physics AB - A detailed theory of nonisothermal electron transport perpendicular to multilayer superlattice structures is presented. The current–voltage (I–V) characteristics and the cooling power density are calculated using Fermi–Dirac statistics, density-of-states for a finite quantum well and the quantum mechanical reflection coefficient. The resulting equations are valid in a wide range of temperatures and electric fields. It is shown that conservation of lateral momentum plays an important role in the device characteristics. If the lateral momentum of the hot electrons is conserved in the thermionic emission process, only carriers with sufficiently large kinetic energy perpendicular to the barrier can pass over it and cool the emitter junction. However, if there is no conservation of lateral momentum, the number of electrons participating in a thermionic emission will increase. This has a significant effect on the I–V measurements as well as the cooling characteristics. Theoretical calculations are compared with the experimental dark current characteristics of quantum well infrared photodetectors and good agreement over a wide temperature range for a variety of superlattice structures is obtained. In contrast with earlier studies, it is shown that lateral momentum is conserved for the case of electron transport in planar semiconductor barriers. DA - 2004/2// PY - 2004/2// DO - 10.1063/1.1635992 VL - 95 IS - 3 SP - 1233-1245 J2 - Journal of Applied Physics LA - en OP - SN - 0021-8979 1089-7550 UR - http://dx.doi.org/10.1063/1.1635992 DB - Crossref ER - TY - JOUR TI - Improved Thermoelectric Power Factor in Metal-Based Superlattices AU - Vashaee, Daryoosh AU - Shakouri, Ali T2 - Physical Review Letters AB - In this paper we present a detailed theory of electron and thermoelectric transport perpendicular to heterostructure superlattices. This nonlinear transport regime above barriers is also called heterostructure thermionic emission. We show that metal-based superlattices with tall barriers can achieve a large effective thermoelectric figure of merit (ZT > 5 at room temperature). A key parameter to achieving high performance is the nonconservation of lateral momentum during the thermionic emission process. Conservation of lateral momentum is a consequence of translational symmetry in the plane of the superlattice. We also discuss the use of nonplanar barriers and embedded quantum dot structures to achieve high thermoelectric conversion efficiency. DA - 2004/3/11/ PY - 2004/3/11/ DO - 10.1103/physrevlett.92.106103 VL - 92 IS - 10 J2 - Phys. Rev. Lett. LA - en OP - SN - 0031-9007 1079-7114 UR - http://dx.doi.org/10.1103/physrevlett.92.106103 DB - Crossref ER - TY - CONF TI - Simultaneous switching noise in IBIS models AU - Varma, A. AU - Lipa, S. AU - Glaser, A. AU - Steer, M. AU - Franzon, P. T2 - 2004 International Symposium on Electromagnetic Compatibility AB - In this paper, a tool to convert SPICE netlists to IBIS (Input/Output Buffer Information Specification) models is presented This tool simulates the netlist on a user-desirable SPICE engine and produces both static and dynamic characteristics of the IBIS model. A CMOS driver circuit is simulated in HSPICE and compared with an equivalent circuit created with IBIS models of the same drivers. Outputs from the drivers are compared IBIS models are also compared against macro-models of nonlinear digital drivers using spline functions with finite time difference approximation modeling techniques. C2 - 2004/8/9/ C3 - Proceedings of the 2004 International Symposium on Electromagnetic Compatibility (IEEE Cat. No.04CH37559) CY - Silicon Valley, CA, USA DA - 2004/8/9/ PY - 2004/8/9/ DO - 10.1109/ISEMC.2004.1349963 VL - 3 SP - 1000–1004 PB - IEEE SN - 0-7803-8443-1 ER - TY - CONF TI - The performance and experimental results of a multiple bit rate symbol timing recovery circuit for PSK receivers AU - Yuce, M.R. AU - Liu, W. AU - Bharat, B. AU - Damaino, J. AU - Franzon, P.D. T2 - IEEE 2004 Custom Integrated Circuits Conference AB - A low-power all-digital symbol timing recovery circuit for digital PSK transmission systems is implemented in a 0.35-/spl mu/m silicon on insulator (SOI) technology. The symbol timing circuit is designed for a wide range of bit rates (0.1-100 kbps) and robust against fast and large Doppler shift or frequency error on the input signal. The system is therefore well-suited for receivers in deep-space and satellite applications. It is synchronized within 3 or 4 bits and the total power dissipation of the circuit is only 310 /spl mu/W. C2 - 2004/// C3 - Proceedings of the IEEE 2004 Custom Integrated Circuits Conference (IEEE Cat. No.04CH37571) CY - Orlando, FL, USA DA - 2004/// PY - 2004/10/3/ DO - 10.1109/CICC.2004.1358893 SP - 591–594 PB - IEEE SN - 0-7803-8495-4 ER - TY - CONF TI - A configurable classification engine for polymorphous chip architecture AU - Yadav, M. AU - Hamilton, P. AU - Sears, R. AU - Viniotis, Y. AU - Conte, T. AU - Franzon, P.D. T2 - ACM BEACON Workshop C2 - 2004/// C3 - Proceedings of the ACM BEACON Workshop CY - Boston, MA DA - 2004/// PY - 2004/10// ER - TY - CONF TI - Pumped-storage hydro-turbine bidding strategies in a competitive electricity market AU - Lu, N. AU - Chow, J.H. AU - Desrochers, A.A. T2 - 2003 IEEE Power Engineering Society General Meeting AB - This paper develops optimal pump-hydro unit bidding strategies in a competitive electricity market. Starting from a weekly forecasted market clearing price (MCP) curve, an algorithm to maximize the profit of a pump-hydro unit considering reserve bids is developed. A comparison between the optimal bidding strategy and a fixed-schedule weekly generating and pumping strategy is provided. C2 - 2004/6/21/ C3 - 2003 IEEE Power Engineering Society General Meeting (IEEE Cat. No.03CH37491) DA - 2004/6/21/ DO - 10.1109/pes.2003.1270415 PB - IEEE SN - 0780379896 UR - http://dx.doi.org/10.1109/pes.2003.1270415 DB - Crossref KW - electricity market deregulation KW - generator bidding strategies KW - optimal pump-hydro unit scheduling KW - fixed weekly schedule optimization KW - reserve bids ER - TY - RPRT TI - Modeling Power Systems as Complex Adaptive Systems AU - Chassin, David P. AU - Malard, Joel M. AU - Posse, Christian AU - Gangopadhyaya, Asim AU - Lu, Ning AU - Katipamula, Srinivas AU - Mallow, J V. A3 - Office of Scientific and Technical Information (OSTI) AB - Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today's most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This report explores the state-of-the-art physical analogs for understanding the behavior of some econophysical systems and deriving stable and robust control strategies for using them. We review and discuss applications of some analytic methods based on a thermodynamic metaphor, according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood. We apply these methods to the question of how power markets can be expected to behave under a variety of conditions. DA - 2004/12/30/ PY - 2004/12/30/ DO - 10.2172/877087 PB - Office of Scientific and Technical Information (OSTI) UR - http://dx.doi.org/10.2172/877087 DB - Crossref ER - TY - JOUR TI - Pumped-Storage Hydro-Turbine Bidding Strategies in a Competitive Electricity Market AU - Lu, N. AU - Chow, J.H. AU - Desrochers, A.A. T2 - IEEE Transactions on Power Systems AB - This paper develops optimal pumped-storage unit bidding strategies in a competitive electricity market. Starting from a weekly forecasted market clearing price curve, an algorithm to maximize the profit of a pumped-storage unit considering reserve bids is developed. A comparison between the optimal bidding strategy and a fixed-schedule weekly generating and pumping strategy is provided. DA - 2004/5// PY - 2004/5// DO - 10.1109/tpwrs.2004.825911 VL - 19 IS - 2 SP - 834-841 J2 - IEEE Trans. Power Syst. LA - en OP - SN - 0885-8950 UR - http://dx.doi.org/10.1109/tpwrs.2004.825911 DB - Crossref KW - electricity market deregulation KW - fixed weekly schedule optimization KW - generator bidding strategies KW - optimal pumped-storage unit scheduling KW - reserve bids ER - TY - BOOK TI - Simulating price responsive distributed resources AU - Lu, N. AU - Chassin, D. P. AU - Widergren, S. E. AU - Ieee DA - 2004/// PY - 2004/// PB - SE - 1538-1543 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000226108300254&KeyUID=WOS:000226108300254 ER - TY - JOUR TI - A state-queueing model of thermostatically controlled appliances AU - Lu, N. AU - Chassin, D. P. T2 - Ieee Transactions on Power Systems AB - This paper develops a state-queueing model to analyze the price response of aggregated loads consisting of thermostatically controlled appliances (TCAs). Assuming a perfectly diversified load before the price response, we show that TCA setpoint changes in response to the market price will result in a redistribution of TCAs in on/off states and therefore change the probabilities for a unit to reside in each state. A randomly distributed load can be partially synchronized and the aggregated diversity lost. The loss of the load diversity can then create unexpected dynamics in the aggregated load profile. Raising issues such as restoring load diversity and damping the peak loads are also addressed in this paper. DA - 2004/// PY - 2004/// DO - 10.1109/tpwrs.2004.831700 VL - 19 IS - 3 SP - 1666-1673 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000222975800050&KeyUID=WOS:000222975800050 KW - demand-side management program KW - load control KW - load modeling KW - price responsive load KW - power distribution KW - state-queueing model KW - thermostatically controlled appliances ER - TY - CONF TI - Integration for Molecular Electronics AU - Franzon, P. AU - Amsinck, C. AU - Di Spigna, N. AU - Sonkusale, Sachin AU - Nackashi, D. C2 - 2004/4// C3 - Proceedings of the Conference on Foundations of NanoScience CY - Snowbird, UT DA - 2004/4// ER - TY - CONF TI - The Design, Fabrication and Characterization of Millimeter Scale Motors for Miniature Direct Drive Robots AU - Palmer, J.A. AU - Mulling, J.F. AU - Dessent, B. AU - Grant, E. AU - Eischen, J.W. AU - Gruverman, A. AU - Kingon, A. AU - Franzon, P.D. T2 - IEEE International Conference on Robotics and Automation AB - This paper reports on research into miniature, direct drive, high force/torque motors to support insect-sized mobile robotic platforms. The primary focus is on scalable motors based on piezoelectric transducers. The contributions of this work include: (1) the design, analysis, and characterization of a miniature mode conversion rotary ultrasonic motor based on a piezoelectric stack transducer; this produced a static torque density of 0.37 Nm/kg, (2) a millimeter scale linear piezometer, constructed with a parallel arrangement of annular stressed unimorph piezoelectric transducers and passive latches, exhibited 0.23 N of blocked force, and (3) simulation data is presented that compares these motor concepts to commercial systems in the context of scalability. Results suggest that smaller versions of the rotary ultrasonic motor would possess a static torque density seven times that of a commercial 3-mm electromagnetic system. This technology shows promise for driving the platform. C2 - 2004/4// C3 - Proceedings of the IEEE International Conference on Robotics and Automation ’04 CY - New Orleans, LA, USA DA - 2004/4// PY - 2004/4/26/ DO - 10.1109/ROBOT.2004.1302454 SP - 4668–4673 PB - IEEE SN - 0-7803-8232-3 KW - piezoelectric KW - scale KW - ultrasonic motor ER - TY - CONF TI - SSN issues with IBIS models AU - Varma, A. AU - Steer, M. AU - Franzon, P. T2 - IEEE Electrical Performance of Electronic Packaging AB - A CMOS driver circuit is simulated in HSPICE and compared with an equivalent circuit created with IBIS (input/output buffer information specification) models of the same drivers. The IBIS models are created using the s2ibis tool from North Carolina State University. IBIS model of the driver is also compared against model created using spline functions with finite time difference approximation modeling techniques. The three modeling techniques are analyzed for accuracy in modeling simultaneous switching noise in drivers. C2 - 2004/10/25/ C3 - Proceedings of the IEEE Conference on Electrical Performance of Electronic Packaging CY - Portland, OR, USA DA - 2004/10/25/ PY - 2004/10/25/ DO - 10.1109/EPEP.2004.1407554 SP - 87–90 PB - IEEE SN - 0-7803-8667-1 ER - TY - CONF TI - Simplified delay design guidelines for on-chip global interconnects AU - Zhang, L. AU - Liu, W. AU - Bashirullah, R. AU - Wilson, J. AU - Franzon, P. T2 - The ACM Great Lakes Symposium on VLSI C2 - 2004/4// DA - 2004/4// SP - 29–32 ER - TY - CONF TI - Configureable String matching hardware for speeding up intrusion detection AU - Aldwairi, M. AU - Conte, T. AU - Franzon, P. C2 - 2004/10// C3 - ACM Workshop on secure networking CY - Boston DA - 2004/10// ER - TY - CONF TI - Rubrics cubed: Tying grades to assessment to reduce faculty workloads AU - Blanchard, S.M. AU - McCord, M.G. AU - Mente, P.L. AU - Lalush, D.S. AU - Abrams, C.F. AU - Loboa, E.G. AU - Nagle, H.T. T2 - The 2004 Annual Conference of the American Association for Engineering Education C2 - 2004/// C3 - Proceedings of the 2004 Annual Conference of the American Association for Engineering Education CY - Salt Lake City, UT DA - 2004/// ER - TY - JOUR TI - An O(N) Semipredictive Universal Encoder via the BWT AU - Baron, D. AU - Bresler, Y. T2 - IEEE Transactions on Information Theory AB - We provide an O(N) algorithm for a nonsequential semipredictive encoder whose pointwise redundancy with respect to any (unbounded depth) tree source is O(1) bits per state above Rissanen's lower bound. This is achieved by using the Burrows-Wheeler transform (BWT), an invertible permutation transform that has been suggested for lossless data compression. First, we use the BWT only as an efficient computational tool for pruning context trees, and encode the input sequence rather than the BWT output. Second, we estimate the minimum description length (MDL) source by incorporating suffix tree methods to construct the unbounded depth context tree that corresponds to the input sequence in O(N) time. Third, we point out that a variety of previous source coding methods required superlinear complexity for determining which tree source state generated each of the symbols of the input. We show how backtracking from the BWT output to the input sequence enables to solve this problem in O(N) worst case complexity. DA - 2004/5// PY - 2004/5// DO - 10.1109/tit.2004.826664 VL - 50 IS - 5 SP - 928-937 SN - 0018-9448 UR - http://dx.doi.org/10.1109/tit.2004.826664 KW - Burrows-Wheeler transform (BWT) KW - context tree pruning KW - data compression KW - dynamic programming KW - lossless source coding KW - minimum description length (MDL) KW - suffix trees KW - tree sources KW - universal coding ER - TY - CHAP TI - Micromachined Ultrasonic Transducers and Their use for 2D and 3D Imaging AU - Khuri-Yakub, B. T. AU - Ergun, A. S. AU - Huang, Y. AU - Cheng, C. H. AU - Oralkan, O. AU - Johnson, J. AU - Yaralioglu, G. G. AU - Karaman, M. T2 - Acoustical Imaging AB - Capacitive micromachined ultrasonic transducers (cMUTs) have proven to have remarkable features such as wide bandwidth and high sensitivity allowing the implementation of systems with wide dynamic range. This paper will review the theory and implementation of CMUTs that enable performance that is superior to piezoelectric transducers. In particular, the paper will discuss one-dimensional and two-dimensional arrays, broad frequency of operation (10 kHz to 50 MHz), and high coupling coefficient (k T 2 value as high as 0.85), and the use of these arrays in imaging applications.Traditionally, the number of transmit and receive processing channels in a full phased array imaging system is equal to the number of transducers in an ultrasound imaging system. Certain applications limit the number of processing channels such that there are fewer channels than transducer elements. For these cases, phased subarray imaging can be used to reduce the number of transducer elements required for each firing event. Experimental images using the full phased array and phased subarray imaging techniques are compared. Initial results indicate that imaging using subarrays leads to a major reduction in hardware with a small reduction in frame rate and signal to noise ratio. PY - 2004/// DO - 10.1007/978-1-4020-2402-3_1 SP - 1-9 OP - PB - Springer Netherlands SN - 9789048166527 9781402024023 UR - http://dx.doi.org/10.1007/978-1-4020-2402-3_1 DB - Crossref ER - TY - CONF TI - Phased subarray imaging for low-cost, wideband coherent array imaging AU - Johnson, J.A. AU - Oralkan, O. AU - Ergun, A.S. AU - Demirci, U. AU - Karaman, M. AU - Khuri-Yakub, B.T. T2 - IEEE Symposium on Ultrasonics, 2003 AB - The front-end hardware complexity of conventional full phased array (FPA) imaging is proportional to the number of array elements. Phased subarray (PSA) imaging has been proposed as a method of reducing the hardware complexity $and therefore system cost and size - while achieving near-FPA image quality. A new method is presented for designing the subarray-dependent interpolation filters suitable for wideband PSA imaging. The method was tested experimentally using pulse-echo data of a wire target phantom acquired using a 3.2-cm, 128-element capacitive micromachines ultrasonic transducer (CMUT) array with 85% fractional bandwidth at 3 MHz. A specific PSA configuration using seven 32-element subarrays was compared to FPA imaging, representing a 4-fold reduction in front-end hardware complexity and a 43% decrease in frame rate. For targets near the fixed transmit focal distance, the mean 6-dB lateral resolution was identical to that of FPA, the axial resolution improved by 4%, and the SNR decreased by 5 dB. Measurements were repeated for 10 different PSA configurations with subarray sizes ranging from 4 to 60. The lateral and axial resolutions did not vary significantly with subarray size; both the SNR and contrast-to-noise ration (CNR) improved with increased subarray size. C2 - 2004/7/9/ C3 - IEEE Symposium on Ultrasonics, 2003 DA - 2004/7/9/ DO - 10.1109/ultsym.2003.1293280 PB - IEEE SN - 0780379225 UR - http://dx.doi.org/10.1109/ultsym.2003.1293280 DB - Crossref ER - TY - CONF TI - Flexible Microsensor Array for the Monitoring and Control of Plant Growth Environment AU - Kim, C.-S. AU - Porterfield, D.M. AU - Nagle, H.T. AU - Brown, C.S. T2 - Habitation Conference C2 - 2004/// DA - 2004/// SP - 186–187 ER - TY - CONF TI - Observations of the Current Change on Acupuncture Spots at Meal Time AU - Chun, Soon-Yong AU - Ji, Un-Ho AU - Nagle, H.T. T2 - IEEE Symposium on Computer-Based Medical Systems C2 - 2004/// DA - 2004/// SP - 490–495 ER - TY - CONF TI - Fuzzy Training for Neural Networks AU - Kermani, B.G. AU - Schiffman, S.S. AU - Nagle, H.T. T2 - The 8th World Multiconference on Systems, Cybernetics, and Informatics C2 - 2004/// C3 - Proceedings of the 8th World Multiconference on Systems, Cybernetics, and Informatics CY - Orlando, FL DA - 2004/// PY - 2004/// VL - IX SP - 124–125 ER - TY - CHAP TI - Environmental Monitoring AU - Nagle, H. Troy AU - Gutierrez-Osuna, Ricardo AU - Kermani, Bahram G. AU - Schiffman, Susan S. T2 - Handbook of Machine Olfaction AB - This chapter contains sections titled: Introduction Water Land Air Special Considerations for Environmental Monitoring Sample Handling Problems Signal Processing Challenges Case Study 1: Livestock Odor Classification Background Description of the problem Methods Signal Processing Algorithms Results Discussion Case Study 2: Swine Odor Detection Thresholds Description of the Problem Methods Results Discussion Case Study 3: Biofilter Evaluation Description of the Problem Methods Results Discussion Case Study 4: Mold Detection Background Description of the Problem The NC State E-Nose Methods Results Discussion Future Directions PY - 2004/1/15/ DO - 10.1002/3527601597.ch17 SP - 419-444 OP - PB - Wiley-VCH Verlag GmbH & Co. KGaA SN - 3527303588 3527601597 UR - http://dx.doi.org/10.1002/3527601597.ch17 DB - Crossref ER - TY - CHAP TI - Signal Conditioning and Preprocessing AU - Gutierrez-Osuna, R. AU - Nagle, H. Troy AU - Kermani, B. AU - Schiffman, Susan S. T2 - Handbook of Machine Olfaction AB - This chapter contains sections titled: Introduction Interface Circuits Chemoresistors Acoustic Wave Sensors Field-Effect Gas Sensors Temperature Control Signal Conditioning Operational Amplifiers Buffering Amplification Filtering Compensation Signal Preprocessing Baseline Manipulation Compression Normalization Noise in Sensors and Circuits Outlook Temperature Modulation Conclusions Acknowledgements PY - 2004/1/15/ DO - 10.1002/3527601597.ch5 SP - 105-132 OP - PB - Wiley-VCH Verlag GmbH & Co. KGaA SN - 3527303588 3527601597 UR - http://dx.doi.org/10.1002/3527601597.ch5 DB - Crossref ER - TY - RPRT TI - Compressing Piecewise Smooth Multidimensional Functions Using Surflets: Rate-Distortion Analysis AU - Chandrasekaran, V. AU - Wakin, M. AU - Baron, D. AU - Baraniuk, R.G. A3 - Electrical and Computer Engineering Department, Rice University DA - 2004/3// PY - 2004/3// M3 - Technical Report PB - Electrical and Computer Engineering Department, Rice University ER - TY - CONF TI - Compression of Higher Dimensional Functions Containing Smooth Discontinuities AU - Chandrasekaran, V. AU - Wakin, M. AU - Baron, D. AU - Baraniuk, R.G. T2 - CISS 2004 C2 - 2004/3// C3 - Proceedings of 38th Annual Conference on Information Sciences and Systems DA - 2004/3// ER - TY - CONF TI - Probability Assignments with Worst-Case Coding Length Constraints AU - Baron, D. AU - Singer, A. AU - Baraniuk, R.G. T2 - CISS 2004 C2 - 2004/// C3 - Proceedings of 38th Annual Conference on Information Sciences and Systems DA - 2004/// ER - TY - CONF TI - Redundancy Rates of Slepian-Wolf Coding AU - Baron, D. AU - Khojastepour, M.A. AU - Baraniuk, R.G. C2 - 2004/9// C3 - Proceedings of 42d Allerton Conference on Communication, Control, and Computing DA - 2004/9// ER - TY - CONF TI - Surflets: a sparse representation for multidimensional functions containing smooth discontinuities AU - Chandrasekaran, V. AU - Wakin, M.B. AU - Baron, D. AU - Baraniuk, R.G. T2 - International Symposium onInformation Theory, 2004. ISIT 2004. Proceedings. AB - Discontinuities in data often provide vital information, and representing these discontinuities sparsely is an important goal for approximation and compression algorithms. Little work has been done on efficient representations for higher dimensional functions containing arbitrarily smooth discontinuities. We consider the N-dimensional Horizon class-N-dimensional functions containing a C/sup K/ smooth (N-1)-dimensional singularity separating two constant regions. We derive the optimal rate-distortion function for this class and introduce the multiscale surflet representation for sparse piecewise approximation of these functions. We propose a compression algorithm using surflets that achieves the optimal asymptotic rate-distortion performance for Horizon functions. This algorithm can be implemented using knowledge of only the N-dimensional function, without explicitly estimating the (N-1)-dimensional discontinuity. C2 - 2004/12/23/ C3 - International Symposium onInformation Theory, 2004. ISIT 2004. Proceedings. DA - 2004/12/23/ DO - 10.1109/isit.2004.1365602 PB - IEEE SN - 0780382803 UR - http://dx.doi.org/10.1109/isit.2004.1365602 DB - Crossref ER - TY - JOUR TI - AES Packet Encryption on a SIMD Stream Architecture AU - Lai, Y. AU - Byrd, G.T. T2 - International Journal of Computer Research DA - 2004/// PY - 2004/// IS - Special Issue on Cryptographic Hardware and Embedded Systems ER - TY - CONF TI - Wireless communications using integrated antennas AU - O, K.K. AU - Kim, K. AU - Floyd, B. AU - Mehta, J. AU - Yoon, H. AU - Hung, C.-M. AU - Bravo, D. AU - Dickson, T. AU - Guo, X. AU - Li, R. AU - Trichy, N. AU - Caserta, J. AU - Bomstad, W. AU - Branch, J. AU - Yang, D.-J. AU - Bohorquez, J. AU - Gao, L. AU - Sugavanam, A. AU - Lin, J.-J. AU - Chen, J. AU - Martin, F. AU - Brewer, J. T2 - IEEE International Interconnect Technology Conference AB - The feasibility of integrating antennas and required circuits to form wireless interconnects in foundry digital CMOS technologies has been demonstrated. The key challenges including the effects of metal structures associated with integrated circuits, heat removal, packaging, and interaction between transmitted and received signals and nearby circuits appear to be manageable. This technology can potentially be applied for implementation of a true single chip radio, on-chip and inter-chip communication systems, RFID tags, and others. C2 - 2004/3/22/ C3 - Proceedings of the IEEE 2003 International Interconnect Technology Conference (Cat. No.03TH8695) DA - 2004/3/22/ DO - 10.1109/iitc.2003.1219727 PB - IEEE SN - 0780377974 UR - http://dx.doi.org/10.1109/iitc.2003.1219727 DB - Crossref ER - TY - CONF TI - 60GHz transceiver circuits in SiGe bipolar technology AU - Reynolds, S. AU - Floyd, B. AU - Pfeiffer, U. AU - Zwick, T. T2 - 2004 IEEE International Solid-State Circuits Conference AB - A 60GHz LNA, direct-downconverter, PA, and 20GHz VCO are built in a 200GHz f/sub t/,/f/sub max/, 0.12/spl mu/m SiGe technology. The 10.8mW LNA has 15dB gain, 3.4-4.4dB noise figure and -8.5dBm IIP3. The down converter has 16dB gain, >50dB LO-RF isolation, and 13.4-14.8dB noise figure. The PA delivers 10dBm at 9dB gain. C2 - 2004/9/28/ C3 - 2004 IEEE International Solid-State Circuits Conference (IEEE Cat. No.04CH37519) DA - 2004/9/28/ DO - 10.1109/isscc.2004.1332784 VL - 47 PB - IEEE SN - 0780382676 UR - http://dx.doi.org/10.1109/isscc.2004.1332784 DB - Crossref ER - TY - CONF TI - A 77 GHz SiGe power amplifier for potential applications in automotive radar systems AU - Pfeiffer, U.R. AU - Reynolds, S.K. AU - Floyd, B.A. T2 - 2004 IEE Radio Frequency Integrated Circuits (RFIC) Systems. Digest of Papers AB - We present the performance of a 77 GHz power amplifier for potential applications directed towards automotive radar systems. The circuit was fabricated in a SiGe bipolar preproduction technology. A balanced two-stage common emitter circuit topology was used to achieve 6.1 dB of power gain at 77 GHz and 11.6 dBm output power at 1dB compression. The power amplifier uses a single 2.5 V supply and was fully integrated (including matching elements) to demonstrate its low-cost potential. First experimental results show its broadband characteristic from 40 GHz to 80 GHz and its temperature dependence up to 130/spl deg/C. C2 - 2004/9/28/ C3 - 2004 IEE Radio Frequency Integrated Circuits (RFIC) Systems. Digest of Papers DA - 2004/9/28/ DO - 10.1109/rfic.2004.1320535 SP - 91-94 PB - IEEE SN - 0780383338 UR - http://dx.doi.org/10.1109/rfic.2004.1320535 DB - Crossref KW - power amplifier KW - W-band KW - 77 GHz KW - automotive radar ER - TY - CONF TI - V-band and W-band SiGe bipolar low-noise amplifiers and voltage-controlled oscillators AU - Floyd, B.A. T2 - 2004 IEE Radio Frequency Integrated Circuits (RFIC) Systems. Digest of Papers AB - LNAs and VCOs operating between 50 and 86 GHz have been implemented using a 0.12-/spl mu/m, 200-GHz SiGe bipolar technology. Unbalanced LNAs at 50, 60, and 77 GHz show /spl sim/15 dB of gain, drawing 2, 6, and 8 mA from 1.8 V, respectively. The iCP/sub 1dB/ for the LNAs are from -17 to -20 dBm. The noise figure of the 60-GHz LNA is 4.5 dB. Balanced amplifiers composed of two parallel LNAs with branch-line couplers at the input, and output have also been demonstrated at 60 and 77 GHz, showing 14 and 12-dB gain, respectively. Differential Colpitts VCOs have been implemented at 53, 67, and 85 GHz. Phase noises at a 1-MHz offset are -100, -98, and -94 dBc/Hz, respectively, while tuning ranges are 3.7%, 3.1%, and 2.7%. Each VCO consumes roughly 25 mW, and provides -8 dBm output power to 100 /spl Omega/ differential. C2 - 2004/9/28/ C3 - 2004 IEE Radio Frequency Integrated Circuits (RFIC) Systems. Digest of Papers DA - 2004/9/28/ DO - 10.1109/rfic.2004.1320601 SP - 295-298 PB - IEEE SN - 0780383338 UR - http://dx.doi.org/10.1109/rfic.2004.1320601 DB - Crossref KW - bipolar integrated circuits KW - bipolar transistor amplifiers KW - millimeter wave amplifiers KW - millimeter wave oscillators KW - MMICs KW - voltage controlled oscillators ER - TY - CONF TI - Low-noise amplifier comparison at 2 GHz in 0.25-μm and 0.18-μm RF-CMOS and SiGe BiCMOS AU - Floyd, B.A. AU - Ozis, D. T2 - 2004 IEE Radio Frequency Integrated Circuits (RFIC) Systems. Digest of Papers AB - Low-noise amplifiers (LNA) have been designed and implemented in 0.25-/spl mu/m and 0.18-/spl mu/m SiGe BiCMOS and RF-CMOS technologies. The LNA have been designed for the same WCDMA application and system specifications, allowing meaningful comparisons to be made. This paper presents the design methodology for these bipolar and CMOS switched-gain LNA and compares the simulated and measured results. A bypass switch topology is also presented. The results show that each technology can meet WCDMA LNA specifications. Measurements show noise figures of 1.4, 1.7, and 1.1 dB for LNA implemented in 0.25-/spl mu/m SiGe BiCMOS, 0.25-/spl mu/m CMOS, and 0.18-/spl mu/m SiGe BiCMOS, respectively. These LNA show 14 to 16 dB of gain and +3 to +4-dBm out-of-band IIP3 at 5 to 6 mA current from 3 V. Of these three measured LNA, the 0.18-/spl mu/m bipolar shows the best performance; however, simulations of a 0.18-/spl mu/m RF-CMOS LNA show further improved IIP3. C2 - 2004/9/28/ C3 - 2004 IEE Radio Frequency Integrated Circuits (RFIC) Systems. Digest of Papers DA - 2004/9/28/ DO - 10.1109/rfic.2004.1320566 SP - 185-188 PB - IEEE SN - 0780383338 UR - http://dx.doi.org/10.1109/rfic.2004.1320566 DB - Crossref KW - BiCMOS analog integrated circuits KW - bipolar transistor amplifiers KW - CMOS analog integrated circuits KW - microwave FET amplifiers KW - technology assessment ER - TY - CONF TI - 10+ Gb/s 90nm CMOS serial link demo in CBGA package AU - Rylov, S. AU - Reynolds, S. AU - Storaska, D. AU - Floyd, B. AU - Kapur, M. AU - Zwick, T. AU - Gowda, S. AU - Sorna, M. T2 - Proceedings of the IEEE 2004 Custom Integrated Circuits Conference AB - We report a 10+ Gb/s serial link demo chip in 90-nm CMOS. It consists of a full-rate 4:1 MUX with 8-tap feed-forward equalizer, a half-rate 1:4 DEMUX with programmable peaking pre-amplifier, and a parallel port interface. The chip is housed in CBGA package and uses ESD devices on all pins. The measured maximum speed of stand-alone transmitter and receiver was 11.7 Gb/s and 13.3 Gb/s respectively, and maximum back-to-back operation speed (transmitter+receiver) was 11.4 Gb/s. C2 - 2004/11/30/ C3 - Proceedings of the IEEE 2004 Custom Integrated Circuits Conference (IEEE Cat. No.04CH37571) DA - 2004/11/30/ DO - 10.1109/cicc.2004.1358725 SP - 27-30 PB - IEEE SN - 0780384954 UR - http://dx.doi.org/10.1109/cicc.2004.1358725 DB - Crossref ER - TY - CONF TI - Yalta: a dynamic PKI and secure tuplespaces for distributed coalitions AU - Smith, T.J. AU - Byrd, G.T. T2 - DARPA Information Survivability Conference and Exposition AB - The Yalta project has developed a scalable, reliable application platform for distributed coalitions. The key components of this infrastructure are a reliable, secure tuplespace service, an intrusion-tolerant, threshold-based certification authority, and a scalable certificate revocation and event notification service. These components combine to provide a highly transparent security infrastructure for distributed, dynamic coalition applications. C2 - 2004/3/22/ C3 - Proceedings DARPA Information Survivability Conference and Exposition DA - 2004/3/22/ DO - 10.1109/discex.2003.1194913 PB - IEEE Comput. Soc SN - 0769518974 UR - http://dx.doi.org/10.1109/discex.2003.1194913 DB - Crossref ER - TY - CONF TI - Dynamic PKI and secure tuplespaces for distributed coalitions AU - Smith, T.J. AU - Byrd, G.T. AU - Wu, Xiaoyong AU - Xin, Hongjie AU - Thangavelu, K. AU - Wang, R. AU - Shah, A. T2 - DARPA Information Survivability Conference and Exposition AB - The Yalta project has developed a scalable, reliable application platform for distributed coalitions. The key components of this infrastructure are a reliable, secure tuplespace service, an intrusion-tolerant, threshold-based certification authority, and a scalable certificate revocation and event notification service. These components combine to provide a highly transparent security infrastructure for distributed, dynamic coalition applications. C2 - 2004/3/2/ C3 - Proceedings DARPA Information Survivability Conference and Exposition DA - 2004/3/2/ DO - 10.1109/discex.2003.1194884 PB - IEEE Comput. Soc SN - 0769518974 UR - http://dx.doi.org/10.1109/discex.2003.1194884 DB - Crossref ER - TY - CONF TI - Extending OpenMP to support slipstream execution mode AU - Ibrahim, K.Z. AU - Byrd, G.T. T2 - International Parallel and Distributed Processing Symposium (IPDPS 2003) AB - OpenMP has emerged as a widely accepted standard for writing shared memory programs. Hardware-specific extensions such as data placement are usually needed to improve the scalability of applications based on this standard. This paper investigates the implementation of an OpenMP compiler that supports slipstream execution mode, a new optimization mechanism for CMP-based distributed shared memory multiprocessors. Slipstream mode uses additional processors to reduce communication overhead, rather than to increase parallelism. We discuss how each OpenMP construct can be implemented to take advantage of slipstream mode, and we present a minor extension that allows runtime or compile-time control of slipstream execution. We also investigate the interaction between slipstream mechanisms and OpenMP scheduling. Our implementation supports both static and dynamic scheduling in slipstream mode. We extended the Omni OpenMP compiler to generate binaries that support slipstream mode, and we show the performance of slipstream-enabled codes using OpenMP codes from the NAS Parallel Benchmark suite, running on the SimOS simulator. Our extension to OpenMP allowed the benchmarks to achieve an average performance improvement of 14% with static scheduling. For dynamic scheduling the performance improvement is 12% on average. C2 - 2004/3/22/ C3 - Proceedings International Parallel and Distributed Processing Symposium DA - 2004/3/22/ DO - 10.1109/ipdps.2003.1213119 PB - IEEE Comput. Soc SN - 0769519261 UR - http://dx.doi.org/10.1109/ipdps.2003.1213119 DB - Crossref ER - TY - CONF TI - Analysis of nitride-based quantum well LEDs and novel white LED design AU - Xiao, Dong AU - Kim, Ki W. AU - Bedair, Salah M. AU - Zavada, John M. T2 - Integrated Optoelectronic Devices 2004 A2 - Stockman, Steve A. A2 - Yao, H. Walter A2 - Schubert, E. Fred AB - Fundamental electrical and optical properties of strained wurtzite InGaN/GaN-based quantum well light emitting diodes are calculated based on the Rashba-Sheka-Pikus Hamiltonian in the vicinity of the Gamma point. The theoretical results show an excellent correlation with experiments. A novel design of using AlInGaN as quantum barrier is proposed to realize efficient red emission, which is hard to achieve if GaN is used as barrier. To achieve high efficiency, the important factors relating to the oscillator strength are discussed in detail. C2 - 2004/6/21/ C3 - Light-Emitting Diodes: Research, Manufacturing, and Applications VIII DA - 2004/6/21/ DO - 10.1117/12.524424 PB - SPIE UR - http://dx.doi.org/10.1117/12.524424 DB - Crossref KW - white LED KW - quantum well KW - nitride ER - TY - JOUR TI - Proton radiation response of monolithic Millimeter-wave transceiver building blocks implemented in 200 GHz SiGe technology AU - Kuo, Wei-Min Lance AU - Lu, Yuan AU - Floyd, B.A. AU - Haugerud, B.M. AU - Sutton, A.K. AU - Krithivasan, R. AU - Cressler, J.D. AU - Gaucher, B.P. AU - Marshall, P.W. AU - Reed, R.A. AU - Freeman, G. T2 - IEEE Transactions on Nuclear Science AB - This work presents the first experimental results on the effects of 63.3 MeV proton irradiation on 60 GHz monolithic point-to-point broadband space data link transceiver building blocks implemented in a 200 GHz SiGe heterojunction bipolar transistor (HBT) technology. A SiGe low-noise amplifier and a SiGe voltage-controlled oscillator were each irradiated to proton fluences of 5.0/spl times/10/sup 13/ p/cm/sup 2/. The device and circuit level performance degradation associated with these extreme proton fluences is found to be minimal, suggesting that such SiGe HBT transceivers should be robust from a proton tolerance perspective for space applications, without intentional hardening at either the device or circuit level. DA - 2004/12// PY - 2004/12// DO - 10.1109/tns.2004.839215 VL - 51 IS - 6 SP - 3781-3787 J2 - IEEE Trans. Nucl. Sci. OP - SN - 0018-9499 UR - http://dx.doi.org/10.1109/tns.2004.839215 DB - Crossref KW - heterojunction bipolar transistor (HBT) KW - low-noise amplifier (LNA) KW - millimeter-wave KW - proton irradiation KW - silicon-germanium (SiGe) KW - transceiver KW - voltage-controlled oscillator (VCO) ER - TY - JOUR TI - Forward-viewing CMUT arrays for medical imaging AU - Demirci, U. AU - Ergun, A.S. AU - Oralkan, O. AU - Karaman, M. AU - Khuri-Yakub, B.T. T2 - IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control AB - This paper reports the design and testing of forward-viewing annular arrays fabricated using capacitive micromachined ultrasonic transducer (CMUT) technology. Recent research studies have shown that CMUTs have broad frequency bandwidth and high-transduction efficiency. One- and two-dimensional CMUT arrays of various sizes already have been fabricated, and their viability for medical imaging applications has been demonstrated. We fabricated 64-element, forward-viewing annular arrays using the standard CMUT fabrication process and carried out experiments to measure the operating frequency, bandwidth, and transmit/receive efficiency of the array elements. The annular array elements, designed for imaging applications in the 20 MHz range, had a resonance frequency of 13.5 MHz in air. The immersion pulse-echo data collected from a plane reflector showed that the devices operate in the 5-26 MHz range with a fractional bandwidth of 135%. The output pressure at the surface of the transducer was measured to be 24 kPa/V. These values translate into a dynamic range of 131.5 dB for 1-V excitation in 1-Hz bandwidth with a commercial low noise receiving circuitry. The designed, forward-viewing annular CMUT array is suitable for mounting on the front surface of a cylindrical catheter probe and can provide Doppler information for measurement of blood flow and guiding information for navigation through blood vessels in intravascular ultrasound imaging. DA - 2004/7// PY - 2004/7// DO - 10.1109/tuffc.2004.1320749 VL - 51 IS - 7 SP - 887-895 J2 - IEEE Trans. Ultrason., Ferroelect., Freq. Contr. OP - SN - 0885-3010 UR - http://dx.doi.org/10.1109/tuffc.2004.1320749 DB - Crossref ER - TY - THES TI - Low Voltage (42V) Electrical Power System for Hybrid Electric Vehicles AU - Lukic, Srdjan Miodrag DA - 2004/// PY - 2004/// PB - Illinois Institute of Technology ER - TY - JOUR TI - Effects of drivetrain hybridization on fuel economy and dynamic performance of parallel hybrid electric vehicles AU - Lukic, Srdjan M AU - Emadi, Ali T2 - IEEE transactions on vehicular technology DA - 2004/// PY - 2004/// VL - 53 IS - 2 SP - 385-389 ER - TY - JOUR TI - Thermal Williams-Comstock Model for Predicting Transition Lengths in a Heat-Assisted Magnetic Recording System AU - Rausch, T. AU - Bain, J.A. AU - Stancil, D.D. AU - Schlesinger, T.E. T2 - IEEE Transactions on Magnetics AB - A thermal Williams-Comstock recording model was developed to predict the transition length in a longitudinal heat-assisted magnetic recording system. In this paper, we compare the results from the model to experimentally determined transition lengths from a dual-sided heat-assisted magnetic recording spin stand. We found both experimentally and theoretically that there exists an optimal alignment between the thermal profile and the magnetic head, which minimizes the transition length. By properly optimizing the write current and laser power, it was possible to record transitions shorter then those attainable with conventional longitudinal recording. DA - 2004/// PY - 2004/// DO - 10.1109/TMAG.2003.821569 VL - 40 IS - 1 I SP - 137-147 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1342308091&partnerID=MN8TOARS KW - heat-assisted magnetic recording KW - hybrid recording KW - transition length KW - Williams-Comstock recording model ER - TY - JOUR TI - Theoretical Limit to Domain Position Detection Magnetic Amplifying Magnetooptical System AU - Herget, P. AU - Schlesinger, T.E. AU - Stancil, D.D. T2 - IEEE Transactions on Magnetics AB - We developed a model that was used to evaluate the performance of a domain position detection magnetic amplifying magnetooptical system (DPD-MAMMOS). Through the use of the model, we explain the operation of DPD-MAMMOS and demonstrate its advantages. Next, we evaluated the performance of DPD-MAMMOS under the influences of position noise from a theoretical point of view. From this analysis, we estimate that a MAMMOS system will need to attain 30 nm or less of position noise to show a density advantage when used with DPD-MAMMOS. DA - 2004/// PY - 2004/// DO - 10.1109/TMAG.2003.821566 VL - 40 IS - 1 I SP - 105-111 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1342286848&partnerID=MN8TOARS KW - magnetic amplifying magnetooptical systems KW - (MAMMOS) KW - magnetooptic recording KW - position detection ER - TY - CONF TI - Studying the communications potential of the enclosed-space radio channel AU - Van’t Hof, J.P. AU - Stancil, D.D. C2 - 2004/// C3 - IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) DA - 2004/// VL - 2 SP - 1668-1671 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4544278644&partnerID=MN8TOARS ER - TY - JOUR TI - Multipath-enabled super-resolution for rf and microwave communication using phase-conjugate arrays AU - Henty, B.E. AU - Stancil, D.D. T2 - Physical Review Letters AB - We demonstrate experimentally that phase-conjugate techniques can be used to achieve super-resolution focusing of electromagnetic waves in a multipath indoor environment at 2.45 GHz. The focusing phenomena was used to direct independent signals to two locations separated by approximately one-half wavelength, thereby creating two simultaneous channels at the same frequency. An increase in channel capacity is shown to be achievable by an experimental transmission of a 1 Mbps signal over two channels created using a four element phase-conjugate array. DA - 2004/// PY - 2004/// DO - 10.1103/PhysRevLett.93.243904 VL - 93 IS - 24 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-37649029077&partnerID=MN8TOARS ER - TY - CONF TI - MAMMOS read only memory AU - Herget, P. AU - Schlesinger, T.E. AU - Bain, J.A. AU - Stancil, D.D. AU - Awano, H. AB - The concept of a low cost, single layer read only memory (ROM) compatible with the magnetic amplifying magneto-optical system (MAMMOS) is introduced. This ROM technology relies on the creation of nucleation sites in the medium for information storage and read back. Several methods of implementing the MAMMOS ROM are proposed and the distribution of nucleation sites is experimentally investigated to gain a better understanding of how to control these sites. C2 - 2004/// C3 - Proceedings of SPIE - The International Society for Optical Engineering DA - 2004/// DO - 10.1117/12.556950 VL - 5380 SP - 163-170 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-10044240796&partnerID=MN8TOARS KW - MAMMOS KW - coercivity KW - MO KW - coercivity distribution KW - ROM ER - TY - CONF TI - Experimental mode content analysis technique for complex overmoded waveguide systems AU - Cepni, A.G. AU - Stancil, D.D. AU - Brodtkorb, D. C2 - 2004/// C3 - IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) DA - 2004/// VL - 3 SP - 2991-2994 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4544387483&partnerID=MN8TOARS ER - TY - CONF TI - Connection between radiation resistances of antenna in rectangular waveguide and in free-space AU - Nikitin, P.V. AU - Stancil, D.D. C2 - 2004/// C3 - IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) DA - 2004/// VL - 2 SP - 2035-2038 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4544374057&partnerID=MN8TOARS ER - TY - CONF TI - Capacity of multi-antenna array systems for HVAC ducts AU - Cepni, A.G. AU - Stancil, D.D. AU - Xhafa, A.E. AU - Henty, B. AU - Nikitin, P.V. AU - Tonguz, O.K. AU - Brodtkorb, D. C2 - 2004/// C3 - IEEE International Conference on Communications DA - 2004/// VL - 5 SP - 2934-2938 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4143088282&partnerID=MN8TOARS ER - TY - CONF TI - Bandwidth limitations of phase-conjugate arrays used for multipath focusing AU - Henty, B.E. AU - Stancil, D.D. C2 - 2004/// C3 - IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) DA - 2004/// VL - 3 SP - 2792-2795 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4544286650&partnerID=MN8TOARS ER - TY - JOUR TI - A simple path-loss prediction model for HVAC systems AU - Tonguz, O.K. AU - Xhafa, A.E. AU - Stancil, D.D. AU - Cepni, A.G. AU - Nikitin, P.V. AU - Brodtkorb, D. T2 - IEEE Transactions on Vehicular Technology AB - In this paper, we present a simple path-loss prediction model for link budget analysis in indoor wireless local area networks that use heating, ventilation, and air conditioning (HVAC) cylindrical ducts in the 2.4-2.5-GHz industrial, scientific, and medical band. The model we propose predicts the average power loss between a transmitter-receiver pair in an HVAC duct network. This prediction model greatly simplifies the link budget analysis for a complex duct network, making it a convenient and simple tool for system design. The accuracy of our prediction model is verified by an extensive set of experimental measurements. DA - 2004/// PY - 2004/// DO - 10.1109/TVT.2004.830143 VL - 53 IS - 4 SP - 1203-1214 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3943088428&partnerID=MN8TOARS KW - heating KW - ventilation, and air conditioning (HVAC) systems KW - indoor wireless local area networks (WLANs) KW - Internet access KW - path-loss prediction model ER - TY - JOUR TI - CAVA: Hiding L2 Misses with Checkpoint-Assisted Value Prediction AU - Ceze, L. AU - Strauss, K. AU - Tuck, J. AU - Torrellas, J. T2 - IEEE Computer Architecture Letters DA - 2004/// PY - 2004/// SP - 7-10 ER - TY - PAT TI - Patterning methods and systems using reflected interference patterns AU - Herr, D. J. C. AU - Joy, D. C. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - PAT TI - Voice clip search AU - Kermani, B. G. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - PAT TI - Multi-dimensional optical disk AU - Kermani, B. G. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - PAT TI - Method and system for molecular charge storage field effect transistor AU - Misra, V. AU - Bocian, D. AU - Kuhr, W. AU - Lindsey, J. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - PAT TI - Method and apparatus for printing images AU - Kermani, B. G. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - PAT TI - Camera with configurable focus area AU - Kermani, B. G. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - PAT TI - Method for forming a field effect transistor having a high-k gate dielectric and related structure AU - Jeon, J. S. AU - Zhong, H. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - CONF TI - The North Carolina State University women in science and engineering program: a community for living and learning AU - Rajala, S. A. AU - Bottomley, L.J. AU - Parry, E. A. AU - Cohen, J. D. AU - Grant, S. C. AU - Thomas, C. J. AU - Doxey, T. M. AU - Perez, G. AU - Collins, R. E. AU - Spurlin, J. E. C2 - 2004/// C3 - American Society for Engineering Education DA - 2004/// ER - TY - PAT TI - Method and circuits for reducing dead time and reverse recovery loss in buck regulators AU - Bai, Y. AU - Sun, N. AU - Huang, A. Q. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - CHAP TI - Engineering computing as an essential component of inquiry-guided learning AU - Rohrbach, R. AU - Spurlin, J. AU - Mayberry, K AU - Rajala, S. T2 - Teaching and learning through inquiry: A guidebook for institutions and instructors PY - 2004/// PB - Sterling, VA: Stylus Publishing ER - TY - CHAP TI - Shape representation with flexible skew-symmetric distributions AU - Baloch, S. H. AU - Krim, H. AU - Genton, M. G. T2 - Skew-elliptical distibutions and their applications: A journey beyond normality PY - 2004/// DO - 10.1201/9780203492000.ch17 PB - Boca Raton, FL: Chapman & Hall/CRC SN - 1584884312 ER - TY - CONF TI - Safely exploiting multithreaded processors to tolerate memory latency in real-time systems AU - El-Haj-Mahmoud, A. AU - Rotenberg, E. AB - A coarse-grain multithreaded processor can effectively hide long memory latencies by quickly switching to an alternate task when the active task issues a memory request, improving overall throughput. However, dynamic switching cannot be safely exploited to improve throughput in hard-real-time embedded systems. The schedulability of a task-set (guaranteeing all tasks meet deadlines) must be determined a priori using offline schedulability tests. Any computation/memory overlap must be statically accounted for. We develop a novel analytical framework that bounds the overlap between computation of a pipeline-resident-task and on-going memory transfers of other tasks. A simple closed-form schedulability test is derived, that only depends on the aggregate computation (C) and memory (M) components of tasks. Namely, the technique does not require specificity regarding the location of memory transfers within and among tasks and avoids searching all task permutations for a specific feasible schedule. To the best of our knowledge, this is the first work to provide the necessary formalism for safely and tractably exploiting coarse-grain multithreaded processors to tolerate memory latency in hard-real-time systems, exceeding the schedulability limits of classic real-time theory for uniprocessors. Our techniques make it possible to capitalize on higher frequency embedded processors, despite the widening processor-memory speed gap. Experiments with task-sets from C-lab benchmarks reveal improvement in the schedulability of task-sets, measured as the ability to schedule previously infeasible task-sets or reduce utilization for already feasible task-sets. We also demonstrate proof-of-concept by deploying our method in a cycle-level simulator of an ARM11-like embedded microprocessor augmented with multiple register contexts, the same hardware multithreading support available in Ubicom's IP3023 embedded microprocessor. C2 - 2004/// C3 - CASES 2004: International Conference on Compilers, Architecture, and Synthesis for Embedded Systems, September 22-25, 2004, Washington, DC, USA DA - 2004/// DO - 10.1145/1023833.1023837 SP - 2-13 PB - New York: ACM Press SN - 1581138903 ER - TY - JOUR TI - Enforcing safety of real-time schedules on contemporary processors using a virtual simple architecture (VISA) AU - Anantaraman, A AU - Seth, K AU - Rotenberg, E AU - Mueller, F T2 - 25TH IEEE INTERNATIONAL REAL-TIME SYSTEMS SYMPOSIUM, PROCEEDINGS AB - Determining safe and tight upper bounds on the worst-case execution time (WCET) of hard real-time tasks running on contemporary microarchitectures is a difficult problem. Current trends in microarchitecture design have created a complexity wall: by enhancing performance through ever more complex architectural features, systems have become increasingly hard to analyze. This paper extends a framework, introduced previously as virtual simple architecture (VISA), to multitasking real-time systems. The objective of VISA is to obviate the need to statically analyze complex processors by instead shifting the burden of guaranteeing deadlines - in part - onto the hardware. The VISA framework exploits a complex processor that ordinarily operates with all of its advanced features enabled, called the complex mode, but which can also be downgraded to a simple mode by gating off the advanced features. A WCET bound is statically derived for a task assuming the simple mode. However, this abstraction is speculatively undermined at run-time by executing the task in the complex mode. The task's progress is continuously gauged to detect anomalous cases in which the complex mode underperforms, in which case the processor switches to the simple mode to explicitly enforce the overall contractual WCET. The processor typically operates in complex mode, generating significant slack, and the VISA safety mechanism ensures bounded timing in atypical cases. Extra slack can be exploited for reducing power consumption and/or enhancing functionality. By extending VISA from single-task to multi-tasking systems, this paper reveals the full extent of VISA'S powerful abstraction capability. Key missing pieces are filled in: (1) preserving integrity of the gauging mechanism despite disruptions caused by preemptions; (2) demonstrating compatibility with arbitrary scheduling and dynamic voltage scaling (DVS) policies; (3) formally describing VISA speculation overheads in terms of padding tasks' WCETs; and (4) developing a systematic method for minimizing these overheads. We also propose a VISA variant that dynamically accrues the slack needed to facilitate speculation in the complex mode, eliminating the need to statically pad WCETs and thereby enabling VISA-style speculation even in highly-utilized systems. DA - 2004/// PY - 2004/// DO - 10.1109/real.2004.19 SP - 114-125 SN - 1052-8725 ER - TY - JOUR TI - Entanglement in the interaction between two quantum oscillator systems AU - Kim, I AU - Iafrate, GJ T2 - FOUNDATIONS OF PHYSICS LETTERS AB - The fundamental quantum dynamics of two interacting oscillator systems are studied in two different scenarios. In one case, both oscillators are assumed to be linear, whereas in the second case, one oscillator is linear and the other is a non-linear, angular-momentum oscillator; the second case is, of course, more complex in terms of energy transfer and dynamics. These two scenarios have been the subject of much interest over the years, especially in developing an understanding of modern concepts in quantum optics and quantum electronics. In this work, however, these two scenarios are utilized to consider and discuss the salient features of quantum behaviors resulting from the interactive nature of the two oscillators, i.e., coherence, entanglement, spontaneous emission, etc., and to apply a measure of entanglement in analyzing the nature of the interacting systems. The Heisenberg equation for both coupled oscillator scenarios are developed in terms of the relevant reduced kinematics operator variables and parameterized commutator relations. For the second scenario, by setting the relevant commutator relations to one or zero, respectively, the Heisenberg equations are able to describe the full quantum or classical motion of the interaction system, thus allowing us to discern the differences between the fully quantum and fully classical dynamical picture. For the coupled linear and angular-momentum oscillator system in the fully quantum-mechanical description, we consider special examples of two, three, four-level angular momentum systems, demonstrating the explicit appearances of entanglement. We also show that this entanglement persists even as the coupled angular momentum oscillator is taken to the limit of a large number of levels, a limit which would go over to the classical picture for an uncoupled angular momentum oscillator. DA - 2004/11// PY - 2004/11// DO - 10.1007/s10702-004-0902-9 VL - 17 IS - 6 SP - 507-534 SN - 0894-9875 KW - entanglement KW - coupled-boson representation KW - spontaneous emission ER - TY - JOUR TI - Developing portable acoustic arrays on a large-scale e-textile substrate AU - Grant, E. AU - Luthy, K. A. AU - Muth, J. F. AU - Mattos, L. S. AU - Braly, J. C. AU - Seyam, A. AU - Ghosh, T. AU - Dhawan, A. AU - Natarajan, K. T2 - International Journal of Clothing Science and Technology AB - This research deals with the production of electronic textiles (e‐textiles) demonstrators. Initially, the research dealt with the creation of 4×5 microphone array on a large area conformal textile substrate. Once the interface electronics were connected to the 4×5 microphone array, this system became an effective acoustic array. Here, a new acoustic eight microphone array design has been designed, fabricated and tested. Changes were made to improve microphone array performance, and to optimize the associated software for data capture and analysis. This new design was based on UC‐Berkeley mote microcomputer technology. The mote‐based system addresses the issue of scaling acoustic arrays, to allow for distributing microphones over large‐areas, and to allow performance comparisons to be made with the original 4×5 microphone acoustic array. DA - 2004/// PY - 2004/// DO - 10.1108/09556220410520379 VL - 16 IS - 1/2 SP - 73-83 ER - TY - JOUR TI - Tunable terahertz-frequency resonances and negative dynamic conductivity of two-dimensional electrons in group-III nitrides AU - Kim, K. W. AU - Korotyeyev, V. V. AU - Kochelap, V. A. AU - Klimov, A. A. AU - Woolard, D. L. T2 - Journal of Applied Physics AB - We investigated the terahertz (THz)-frequency resonances of two-dimensional electron conductivity under the streaming transport in a GaN quantum well at the nitrogen temperature. The calculation results found that the negative microwave mobility can occur in the narrow windows near the optical-phonon transit-time resonance frequencies, which can be tuned electrically in the 0.2–2.5THz range with the static electric fields of 1–10kV∕cm. The estimated magnitude of the negative mobility reaches hundreds of cm2∕Vs. These effects suggest that the nitride-based heterostructure may enable the development of an electrically pumped, tunable THz source operating at or above 77K. DA - 2004/12// PY - 2004/12// DO - 10.1063/1.1811388 VL - 96 IS - 11 SP - 6488-6491 J2 - Journal of Applied Physics LA - en OP - SN - 0021-8979 1089-7550 UR - http://dx.doi.org/10.1063/1.1811388 DB - Crossref ER - TY - JOUR TI - Phase-plane analysis and classification of transient regimes for high-field electron transport in nitride semiconductors AU - Sokolov, V. N. AU - Kim, K. W. AU - Kochelap, V. A. AU - Woolard, D. L. T2 - Journal of Applied Physics AB - We present a detailed theoretical analysis of steady-state, transient time-dependent, and spatially dependent electron transport in the group-III nitrides at high and ultrahigh electric fields. To develop an analytical model, we derive time-dependent differential equations describing the hot-electron rates of momentum and energy relaxation in electron–polar-optical-phonon scattering and analyze them by employing phase-plane analysis. From the structure of the phase-plane partitioning based on the phase trajectories, the transient regimes are investigated and classified depending on various initial conditions. We have studied different subpicosecond regimes and found a considerable velocity overshoot effect. One of our findings is that when the velocity reaches the maximum, the electron temperature is of a moderate magnitude but increases considerably in the subsequent stage. Dynamic regimes with high electron temperature overshoot have been revealed. For the dominant electron–polar-optical-phonon scattering, the observed overshoot can be treated as a rudiment of the runaway effect typical for that mechanism. In nanoscale nitride diodes with space-charge limited transport, the transient processes are extended to sufficiently larger distances, the overshoot is weaker and the electron heating in the region of the peak velocity is greater than that found for time-dependent problem with a constant electric field throughout a homogeneous sample. DA - 2004/12// PY - 2004/12// DO - 10.1063/1.1808900 VL - 96 IS - 11 SP - 6492-6503 J2 - Journal of Applied Physics LA - en OP - SN - 0021-8979 1089-7550 UR - http://dx.doi.org/10.1063/1.1808900 DB - Crossref ER - TY - JOUR TI - Gain scheduler middleware: A methodology to enable existing controllers for networked control and teleoperation - Part II: Teleoperation AU - Tipsuwan, Y AU - Chow, MY T2 - IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS AB - This paper is the second of two companion papers. The foundation for the external gain scheduling approach to enable an existing controller via middleware for networked control with a case study on a proportional-integral (PI) controller for dc motor speed control over IP networks was given in Part I. Part II extends the concepts and methods of the middleware called gain scheduler middleware (GSM) in Part I to enable an existing controller for mobile robot path-tracking teleoperation. By identifying network traffic conditions in real-time, the GSM will predict the future tracking performance. If the predicted tracking performance tends to be degraded over a certain tolerance due to network delays, the GSM will modify the path-tracking controller output with respect to the current traffic conditions. The path-tracking controller output is modified so that the robot will move with the fastest possible speed, while the tracking performance is maintained in a certain tolerance. Simulation and experimental results on a mobile robot path-tracking platform show that the GSM approach can significantly maintain the robot path-tracking performance with the existence of IP network delays. DA - 2004/12// PY - 2004/12// DO - 10.1109/TIE.2004.837865 VL - 51 IS - 6 SP - 1228-1237 SN - 1557-9948 KW - adaptive control KW - control systems KW - dc motors KW - distributed control KW - Internet KW - mobile robots KW - networks KW - real-time system KW - telerobotics ER - TY - JOUR TI - Gain scheduler middleware: A methodology to enable existing controllers for networked control and teleoperation - Part I: Networked control AU - Tipsuwan, Y AU - Chow, MY T2 - IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS AB - Conventionally, in order to control an application over a data network, a specific networked control or teleoperation algorithm to compensate network delay effects is usually required for controller design. Therefore, an existing controller has to be redesigned or replaced by a new controller system. This replacement process is usually costly, inconvenient, and time consuming. In this paper, a novel methodology to enable existing controllers for networked control and teleoperation by middleware is introduced. The proposed methodology uses middleware to modify the output of an existing controller based on a gain scheduling algorithm with respect to the current network traffic conditions. Since the existing controller can still be utilized, this approach could save much time and investment cost. Two examples of the middleware applied for networked control and teleoperation with IP network delays are given in these two companion papers. Part I of these two companion papers introduces the concept of the proposed middleware approach. Formulation, delay modeling, and optimal gain finding based on a cost function for a case study on DC motor speed control with a proportional-integral (PI) controller are also described. Simulation results of the PI controller shows that, with the existence of IP network delays, the middleware can effectively maintain the networked control system performance and stabilize the system. Part II of this paper will cover the use of the proposed middleware concept for a mobile robot teleoperation. DA - 2004/12// PY - 2004/12// DO - 10.1109/TIE.2004.837866 VL - 51 IS - 6 SP - 1218-1227 SN - 1557-9948 KW - adaptive control KW - control systems KW - dc motors KW - distributed control KW - Internet KW - mobile robots KW - networks KW - real-time system KW - telerobotics ER - TY - JOUR TI - Surface passivation of n-GaN by nitrided-thin-Ga2O3/SiO2 and Si3N4 films AU - Bae, C AU - Krug, C AU - Lucovsky, G AU - Chakraborty, A AU - Mishra, U T2 - JOURNAL OF APPLIED PHYSICS AB - The electrical characteristics of n-GaN∕nitrided-thin-Ga2O3∕SiO2 and n-GaN∕Si3N4 metal-insulator-semiconductor (MIS) capacitors have been compared, and the work-function difference ϕms and effective dielectric-fixed charge density Qf,eff have been determined. Oxide samples showed lower interface trap level density Dit, lower leakage current, and better reproducibility compared to the nitride samples. The superior properties of the oxide samples are partially attributed to the nitrided-thin-Ga2O3 layer (∼0.6-nm-thick). ϕms and Qf,eff were determined, respectively, as 0.13V and 1.0×1012qcm−2 in oxide and 0.27V and −3.6×1011qcm−2 in nitride samples using flatband voltage versus dielectric thickness data. True dielectric-fixed charge density and location of the major amount of fixed charge are discussed based on Qf,eff, Dit, and spontaneous polarization of n-GaN. DA - 2004/9/1/ PY - 2004/9/1/ DO - 10.1063/1.1772884 VL - 96 IS - 5 SP - 2674-2680 SN - 1089-7550 ER - TY - JOUR TI - Observed and modeled VOC chemistry under high VOC/NOx conditions in the Southeast United States national parks AU - Kang, DW AU - Aneja, VP AU - Mathur, R AU - Ray, JD T2 - ATMOSPHERIC ENVIRONMENT AB - In airsheds that contain high volatile organic compounds (VOCs) and low NOx (=NO+NO2) concentrations, ozone (O3) production may be significantly suppressed by NOx reactions that lead to the formation of organic nitrates. O3 and its precursors (VOCs and NOx) ambient levels simulated using a regional-scale photochemical model, called Multiscale Air Quality Simulation Platform, are analyzed and compared to observed data from three southeast United States national parks. DA - 2004/9// PY - 2004/9// DO - 10.1016/j.atmosenv.2004.05.054 VL - 38 IS - 29 SP - 4969-4974 SN - 1352-2310 KW - VOCs KW - ozone KW - atmospheric chemistry KW - air quality modeling ER - TY - JOUR TI - Noise reduction in surface reconstruction from a given gradient field AU - Karacali, B AU - Snyder, W T2 - INTERNATIONAL JOURNAL OF COMPUTER VISION DA - 2004/10// PY - 2004/10// DO - 10.1023/B:VISI.0000027788.50090.b6 VL - 60 IS - 1 SP - 25-44 SN - 1573-1405 KW - surface reconstruction KW - gradient field KW - noise reduction KW - thresholding KW - projection KW - gradient space KW - orthonormal representation KW - multiscale analysis ER - TY - JOUR TI - Multiple-bit storage properties of porphyrin monolayers on SiO2 AU - Li, QL AU - Surthi, S AU - Mathur, G AU - Gowda, S AU - Zhao, Q AU - Sorenson, TA AU - Tenent, RC AU - Muthukumaran, K AU - Lindsey, JS AU - Misra, V T2 - APPLIED PHYSICS LETTERS AB - Hybrid molecule-silicon capacitors have been fabricated by the self-assembly of a monolayer of porphyrin molecules on a silicon oxide surface. The porphyrin employed [5-(4-dihydroxyphosphorylphenyl)-10,15,20-trimesitylporphinatozinc(II)] attaches to silicon oxide via a phosphonate linkage. Cyclic voltammetry current and capacitance/conductance measurements have been used to characterize the capacitors. The presence of multiple distinct peaks in current density and capacitance/conductance measurements are associated with oxidation and reduction of the molecular monolayer. The charge-storage states of the capacitor indicate applicability for use in multiple-bit memory devices. DA - 2004/9/6/ PY - 2004/9/6/ DO - 10.1063/1.1782254 VL - 85 IS - 10 SP - 1829-1831 SN - 1077-3118 ER - TY - JOUR TI - Manipulation of microenvironment with a built-in electrochemical actuator in proximity of a dissolved oxygen microsensor AU - Kim, CS AU - Lee, CH AU - Fiering, JO AU - Ufer, S AU - Scarantino, CW AU - Nagle, HT T2 - IEEE SENSORS JOURNAL AB - Biochemical sensors for continuous monitoring require dependable periodic self diagnosis with acceptable simplicity to check its functionality during operation. An in-situ self-diagnostic technique for a dissolved oxygen microsensor is proposed in an effort to devise an intelligent microsensor system with an integrated electrochemical actuation electrode. With a built-in platinum microelectrode that surrounds the microsensor, two kinds of microenvironments, called the oxygen-saturated or oxygen-depleted phases, can be created by water electrolysis, depending on the polarity. The functionality of the microsensor can be checked during these microenvironment phases. The polarographic oxygen microsensor is fabricated on a flexible polyimide substrate (Kapton) and the feasibility of the proposed concept is demonstrated in a physiological solution. The sensor responds properly during the oxygen-generating and oxygen-depleting phases. The use of these microenvironments for in-situ self-calibration is discussed to achieve functional integration, as well as structural integration, of the microsensor system. DA - 2004/10// PY - 2004/10// DO - 10.1109/JSEN.2004.832857 VL - 4 IS - 5 SP - 568-575 SN - 1558-1748 KW - electrolysis KW - intelligent microsensor KW - polyimide KW - self calibration KW - self diagnosis ER - TY - JOUR TI - Correlation of phonon decay with localized electron spin-phase diffusion AU - Semenov, Y. G. AU - Kim, K. W. T2 - Physical Review B AB - A spin decoherence mechanism is proposed for localized electrons. The irregular phonon phase disturbances originated from phonon relaxation can influence electron spin precession with a net effect of spin phase decay. A quantitative analysis demonstrates relatively high efficiency of this mechanism in the low temperature and low magnetic field regime compared to the spin-flip processes. DA - 2004/8/10/ PY - 2004/8/10/ DO - 10.1103/physrevb.70.085305 VL - 70 IS - 8 SP - J2 - Phys. Rev. B LA - en OP - SN - 1098-0121 1550-235X UR - http://dx.doi.org/10.1103/PhysRevB.70.085305 DB - Crossref ER - TY - JOUR TI - Causal reduced-order modeling of distributed structures in a transient circuit simulator AU - Mohan, R AU - Choi, MJ AU - Mick, SE AU - Hart, FP AU - Chandrasekar, K AU - Cangellaris, AC AU - Franzon, PD AU - Steer, MB T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - Fosters' canonical representation of the transfer characteristic of a linear system is the key to causal fully convergent incorporation of distributed structures in transient circuit simulators. The implementation of the Foster's model in the fREEDA circuit simulator is reported and the modeling of a two-port coupled inductor is presented as an example. DA - 2004/9// PY - 2004/9// DO - 10.1109/TMTT.2004.834588 VL - 52 IS - 9 SP - 2207-2214 SN - 1557-9670 KW - Foster's canonical model KW - transient circuit simulation ER - TY - JOUR TI - Analyzing a two-stage queueing system with many point process arrivals at upstream queue AU - Eun, DY AU - Shroff, NB T2 - QUEUEING SYSTEMS DA - 2004/// PY - 2004/// DO - 10.1023/B:QUES.0000039886.54866.c5 VL - 48 IS - 1-2 SP - 23-43 SN - 1572-9443 KW - queueing networks KW - overflow probability KW - many-sources-asymptotic KW - point processes ER - TY - JOUR TI - An implantable radiation dosimeter for use in external beam radiation therapy AU - Scarantino, CW AU - Ruslander, DM AU - Rini, CJ AU - Mann, GG AU - Nagle, HT AU - Black, RD T2 - MEDICAL PHYSICS AB - An implantable radiation dosimeter for use with external beam therapy has been developed and tested both in vitro and in canines. The device uses a MOSFET dosimeter and is polled telemetrically every day during the course of therapy. The device is designed for permanent implantation and also acts as a radiographic fiducial marker. Ten dogs (companion animals) that presented with spontaneous, malignant tumors were enrolled in the study and received an implant in the tumor CTV. Three dogs received an additional implant in collateral normal tissue. Radiation therapy plans were created for the animals and they were treated with roughly 300 cGy daily fractions until completion of the prescribed cumulative dose. The primary endpoints of the study were to record any adverse events due to sensor placement and to monitor any movement away from the point of placement. No adverse events were recorded. Unacceptable device migration was experienced in two subjects and a retention mechanism was developed to prevent movement in the future. Daily dose readings were successfully acquired in all subjects. A rigorous in vitro calibration methodology has been developed to ensure that the implanted devices maintain an accuracy of ±3.5% relative to an ionization chamber standard. The authors believe that an implantable radiation dosimeter is a practical and powerful tool that fosters individualized patient QA on a daily basis. DA - 2004/9// PY - 2004/9// DO - 10.1118/1.1778809 VL - 31 IS - 9 SP - 2658-2671 SN - 2473-4209 KW - radiation KW - dosimetry KW - in vivo ER - TY - JOUR TI - A "Defect level versus cost" system tradeoff for electronics manufacturing AU - Scheffler, M AU - Franzon, PD AU - Troster, G T2 - IEEE TRANSACTIONS ON ELECTRONICS PACKAGING MANUFACTURING AB - Both cost and quality are important features when manufacturing today's high-performance electronics. Unfortunately, the two design goals (low) cost and (high) quality are somewhat mutually exclusive. High testing effort (and thus, quality) comes with a considerable cost, and lowering test activities has significant impact on the delivered quality. In this paper, we present a new structured search method to obtain the best combination of these two goals. It features a Petri-net oriented cost/quality modeling approach and uses a Pareto chart to visualize the results. The search for the Pareto-optimal points is done by means of a genetic algorithm. With our method, we optimize a manufacturing process for a global positioning system (GPS) front end. The optimized process clearly outperformed the standard fabrication process. DA - 2004/1// PY - 2004/1// DO - 10.1109/TEPM.2004.830513 VL - 27 IS - 1 SP - 67-76 SN - 1521-334X KW - cost quality tradeoff KW - genetic algorithm KW - high-density packaging (HDP) KW - Pareto chart ER - TY - JOUR TI - Work-function difference between Al and n-GaN from Al-gated n-GaN/nitrided-thin-Ga2O3/SiO2 metal oxide semiconductor structures AU - Bae, C. AU - Krug, C. AU - Lucovsky, G. AU - Chakraborty, A. AU - Mishra, U. T2 - Applied Physics Letters AB - In most previous reports on Al-gated n-GaN∕SiO2 metal–oxide–semiconductor (MOS) structures, the work–function difference between Al and n-GaN (ϕms) has been chosen as 0V by assuming that the work function of the Al gate and n-GaN are both 4.1eV. In this letter, ϕms is determined as ∼0.1V using Al-gated n-GaN∕nitrided-thin-Ga2O3∕SiO2 MOS capacitors by measuring flatband voltage as a function of oxide thickness. Formation of an ultrathin (∼0.6-nm-thick) Ga2O3 layer on n-GaN prior to the deposition of SiO2 is important to prevent uncontrolled parasitic oxidation of then-GaN surface and possibly reduces the interface dipole between n-GaN and SiO2. DA - 2004/// PY - 2004/// DO - 10.1063/1.1767599 VL - 84 IS - 26 SP - 5413-5415 ER - TY - JOUR TI - Spin polaron and bistability in ferromagnetic semiconductor quantum structures AU - Semenov, Y. G. AU - Kim, K. W. T2 - Physical Review B AB - This work shows that the in-plane localization of a hole confined in a ferromagnetic semiconductor quantum well (QW) can lead to significant energy gain if spontaneous easy-plane magnetization is mediated by the mechanisms other than itinerant carriers. The hole spin normal to the QW plane reorients the in-plane magnetization of the ferromagnetic layer at the location of polaron formation, resulting in an exchange potential with a discrete level of localization. A flexible model that incorporates the magnetization gradient term, as well as magnetic anisotropy, is proposed. In contrast to the calculations of magnetic polaron in the paramagnetic semiconductors, the energy of spin polaron in a ferromagnetic semiconductor is almost independent of the temperature in a wide range below the critical temperature of phase transition. Our calculation also demonstrates the existence of bistability in the hole state when the structure consists of appropriate ferromagnetic and nonmagnetic QWs separated by a finite barrier. Hence, a memory element that can be scaled down to a single hole may be achieved through polaron formation. DA - 2004/9/7/ PY - 2004/9/7/ DO - 10.1103/physrevb.70.125303 VL - 70 IS - 12 SP - J2 - Phys. Rev. B LA - en OP - SN - 1098-0121 1550-235X UR - http://dx.doi.org/10.1103/PhysRevB.70.125303 DB - Crossref ER - TY - JOUR TI - Spectral spaces and color spaces AU - Ramanath, R AU - Kuehni, RG AU - Snyder, WE AU - Hinks, D T2 - COLOR RESEARCH AND APPLICATION AB - Abstract It has long been known that color experiences under controlled conditions may be ordered into a color space based on three primary attributes. It is also known that the color of an object depends on its spectral reflectance function, among other factors. Using dimensionality reduction techniques applied to reflectance measurements (in our case a published set of 1 nm interval reflectance functions of Munsell color chips) it is possible to construct 3D spaces of various kinds. In this article we compare color spaces, perceptual or based on dimensionality reduction using color matching functions and additional operations (uniform color space), to spectral spaces derived with a variety of dimensionality reduction techniques. Most spectral spaces put object spectra into the ordinal order of a psychological color space, but so do many random continuous functions. In terms of interval scales there are large differences between color and spectral spaces. In spectral spaces psychophysical metamers are located in different places. © 2003 Wiley Periodicals, Inc. Col Res Appl, 29, 29–37, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10211 DA - 2004/2// PY - 2004/2// DO - 10.1002/col.10211 VL - 29 IS - 1 SP - 29-37 SN - 1520-6378 KW - color spaces KW - metamerism KW - Munsell system KW - spectral spaces KW - spectrophotometry ER - TY - CHAP TI - Scanning tunneling microscope-quartz crystal microbalance studies of "real world" and model lubricants AU - Krim, J. AU - Abdelmaksoud, M. AU - Borovsky, B. AU - Winder, S. M. T2 - Dynamics and friction of submicrometer confining systems AB - Applications of the Quartz Crystal Microbalance (QCM) for studies of tribology at atomistic time and length scales are described herein. Employing QCM as the sole technique, we report measurements on vapor phase lubricants for "real world" applications, and rare-gas systems that are of more fundamental interest. We also report on QCM measurements that have been recorded in conjunction with a Scanning Tunneling Microscope (STM). The QCM-STM apparatus allows unique and detailed investigations of a simple nanomechanical system formed by a contacting tip and surface. Both STM images of the contact and the response of the QCM are monitored throughout the course of the measurements, which are performed at realistic sliding speeds of over 1 m/s. CN - QC176.8 .N35 D96 2004 [Hill] PY - 2004/// DO - 10.1021/bk-2004-0882.ch001 VL - 882 PB - Washington, D.C.: American Chemical Society ER - TY - JOUR TI - Resonance-like electrical control of electron spin for microwave measurement AU - Glavin, B. A. AU - Kim, K. W. T2 - Applied Physics Letters AB - We demonstrate that the spin-polarized electron current can interact with a microwave electric field in a resonant manner. The spin–orbit interaction gives rise to an effective magnetic field proportional to the electric current. In the presence of both dc and ac electric field components, electron spin resonance occurs if the ac frequency matches the spin precession frequency that is controlled by the dc field. In a device consisting of two spin-polarized contacts connected by a two-dimensional channel, this mechanism allows electrically tuned detection of the ac signal frequency and amplitude. For GaAs, such detection is effective in the frequency domain around tens of gigahertz. DA - 2004/7/19/ PY - 2004/7/19/ DO - 10.1063/1.1773359 VL - 85 IS - 3 SP - 428-430 J2 - Appl. Phys. Lett. LA - en OP - SN - 0003-6951 1077-3118 UR - http://dx.doi.org/10.1063/1.1773359 DB - Crossref ER - TY - JOUR TI - Reliable adaptive modulation aided by observations of another fading channel AU - Yang, TS AU - Duel-Hallen, A AU - Hallen, H T2 - IEEE TRANSACTIONS ON COMMUNICATIONS AB - Adaptive transmission techniques, such as adaptive modulation and coding, adaptive power control, adaptive transmitter antenna diversity, etc., generally require precise channel estimation and feedback of channel state information (CSI). For fast vehicle speeds, reliable adaptive transmission also requires long-range prediction of future CSI, since the channel conditions are rapidly time variant. In this paper, we propose using past channel observations of one carrier to predict future CSI and perform adaptive modulation without feedback for another correlated carrier. We derive the minimum mean-square error (MMSE) long-range channel prediction that uses the time- and frequency-domain correlation function of the Rayleigh fading channel. An adaptive MMSE prediction method is also proposed. A statistical model of the prediction error that depends on the frequency and time correlation is developed and is used in the design of reliable adaptive modulation methods. We use a standard stationary fading channel model (Jakes model) and a novel physical channel model to test our algorithm. Significant gains relative to nonadaptive techniques are demonstrated for sufficiently correlated channels and realistic prediction range. DA - 2004/4// PY - 2004/4// DO - 10.1109/TCOMM.2004.826369 VL - 52 IS - 4 SP - 605-611 SN - 1558-0857 UR - http://dx.doi.org/10.1109/TCOMM.2004.826369 KW - adaptive modulation KW - fading channel prediction KW - multipath fading KW - multiple carriers KW - physical channel modeling ER - TY - JOUR TI - Reductions in interface defects, D-it, by post oxidation plasma-assisted nitridation of GaN-SiO2 interfaces in MOS devices AU - Bae, C AU - Lucovsky, G T2 - SURFACE SCIENCE AB - This paper applies remote plasma processing techniques, remote plasma assisted oxidation (nitridation) RPAO(N) and RP enhanced chemical vapor deposition (RPECVD), developed originally for fabrication of Si MOS devices with deposited SiO2, Si3N4 and Si oxynitride alloys to the formation of device-quality GaN MOS devices. Significant improvements in device performance for GaN–SiO2 interfaces are demonstrated by following an RPAO process step that forms the device interface with an interface nitridation RPAN step prior to the deposition of an SiO2 dielectric film by RPECVD. On-line Auger electron spectroscopy is used to monitor interface bonding for different ordering of RPAO and RPAN process steps. DA - 2004/9/20/ PY - 2004/9/20/ DO - 10.1016/j.susc.2004.05.072 VL - 566 SP - 356-360 SN - 1879-2758 KW - interface states KW - dielectric phenomena KW - plasma processing KW - surface defects KW - metal-oxide-semiconductor (MOS) structures ER - TY - JOUR TI - Phonon-Mediated Electron-Spin Phase Diffusion in a Quantum Dot AU - Semenov, Y. G. AU - Kim, K. W. T2 - Physical Review Letters AB - An effective spin relaxation mechanism that leads to electron spin decoherence in a quantum dot is proposed. In contrast with the common calculations of spin-flip transitions between the Kramers doublets, we take into account a process of phonon-mediated fluctuation in the electron spin preces-sion and subsequent spin phase diffusion. Specifically, we consider modulations in the longitudinal g factor and hyperfine interaction induced by the phonon-assisted transitions between the lowest electronic states. Prominent differences in the temperature and magnetic field dependence between the proposed mechanism and the spin-flip transitions are expected to facilitate its experimental verification. Numerical estimation demonstrates highly efficient spin relaxation in typical semiconductor quantum dots. DA - 2004/1/13/ PY - 2004/1/13/ DO - 10.1103/physrevlett.92.026601 VL - 92 IS - 2 SP - J2 - Phys. Rev. Lett. LA - en OP - SN - 0031-9007 1079-7114 UR - http://dx.doi.org/10.1103/PhysRevLett.92.026601 DB - Crossref ER - TY - JOUR TI - Opportunities and challenges in embedded systems AU - Bechini, A. AU - Conte, T. M. AU - Prete, C. A. T2 - IEEE Micro DA - 2004/// PY - 2004/// VL - 24 IS - 4 SP - 38208 ER - TY - JOUR TI - Network decomposition in the many-sources regime AU - Eun, DY AU - Shroff, NB T2 - ADVANCES IN APPLIED PROBABILITY AB - We derive results that show the impact of aggregation in a queueing network. Our model consists of a two-stage queueing system where the first (upstream) queue serves many flows, of which a certain subset arrive at the second (downstream) queue. The downstream queue experiences arbitrary interfering traffic. In this setup, we prove that, as the number of flows being aggregated in the upstream queue increases, the overflow probability of the downstream queue converges uniformly in the buffer level to the overflow probability of a single queueing system obtained by simply removing the upstream queue in the original two-stage queueing system. We also provide the speed of convergence and show that it is at least exponentially fast. We then extend our results to non-i.i.d. traffic arrivals. DA - 2004/9// PY - 2004/9// DO - 10.1239/aap/1093962240 VL - 36 IS - 3 SP - 893-918 SN - 1475-6064 KW - aggregation KW - queueing network KW - many-sources asymptotic KW - speed of convergence ER - TY - CONF TI - Microwave properties of BST thin film interdigital capacitors on low cost alumina substrates AU - Nath, J. AU - Ghosh, D. AU - Maria, J.-P. AU - Steer, M. B. AU - Kingon, A. I. AU - Stauf, G. T. C2 - 2004/// C3 - Proceedings of the 34th European Microwave Conference (EuMc), Amsterdam DA - 2004/// SP - 1497-1500 PB - London: Horizon House SN - 1580539920 ER - TY - JOUR TI - Low-field electron runaway and spontaneous formation of two-beam velocity distribution in polar semiconductors AU - Komirenko, S. M. AU - Kim, K. W. AU - Kochelap, V. A. AU - Woolard, D. L. T2 - Physical Review B AB - We show that high-energy electron injection into a polar semiconductor can lead to a spontaneous splitting of the electron beam into two distinct groups with different velocity distributions. While one group of electrons experiences thermalization in a given subthreshold field, the velocity and energy of the second group increases with distance due to the previously unknown low-field electron runaway effect. We investigate the dependence of the carrier distribution on the injection energy, and show that the overall distribution exhibits a partial population inversion with a distance-dependent energy gap between the thermalized and runaway electrons. The low-field runaway is a universal effect which is characteristic of nanoscale semiconductors where polar optical phonon scattering predominates and there is a large intervalley energy separation as in the group-III nitride heterostructures. DA - 2004/6/10/ PY - 2004/6/10/ DO - 10.1103/physrevb.69.233201 VL - 69 IS - 23 SP - J2 - Phys. Rev. B LA - en OP - SN - 1098-0121 1550-235X UR - http://dx.doi.org/10.1103/PhysRevB.69.233201 DB - Crossref ER - TY - JOUR TI - Efficient real-time fine-grained concurrency on low-cost microcontrollers AU - Dean, A. G. T2 - IEEE Micro DA - 2004/// PY - 2004/// VL - 24 IS - 4 SP - 38282 ER - TY - JOUR TI - Design of white light-emitting diodes using InGaN/AlInGaN quantum-well structures AU - Xiao, D. AU - Kim, K. W. AU - Bedair, S. M. AU - Zavada, J. M. T2 - Applied Physics Letters AB - Based on the Rashba–Sheka–Pikus Hamiltonian in the vicinity of the Γ point, and taking into consideration spontaneous and piezoelectric polarization, the optical intensity of nitride-based quantum-well light-emitting diodes has been calculated. It is found that strain substantially alters the subband structure and thus the output intensity of these nitride-biased quantum-well light-emitting diodes. A design that uses AlInGaN as the quantum barrier is proposed to realize efficient red emission, which is hard to achieve if GaN is used as the barrier. In the proposed design, three different InGaN/AlInGaN quantum-well structures emit red, green, and blue light of similar intensity. Also, to achieve high efficiency, important factors related to the oscillator strength are discussed in detail. DA - 2004/2/2/ PY - 2004/2/2/ DO - 10.1063/1.1644920 VL - 84 IS - 5 SP - 672-674 J2 - Appl. Phys. Lett. LA - en OP - SN - 0003-6951 1077-3118 UR - http://dx.doi.org/10.1063/1.1644920 DB - Crossref ER - TY - JOUR TI - Dependence of ferromagnetic properties on carrier transfer at GaMnN/GaN : Mg interface AU - Arkun, FE AU - Reed, MJ AU - Berkman, EA AU - El-Masry, NA AU - Zavada, JM AU - Reed, ML AU - Bedair, SM T2 - APPLIED PHYSICS LETTERS AB - We report on the dependence of ferromagnetic properties of metalorganic chemical vapor deposition grown GaMnN films on carrier transfer across adjacent layers. We found that the magnetic properties of GaMnN, as a part of GaMnN∕GaN:Mg heterostructures, depend on the thickness of both the GaMnN film and the adjacent GaN:Mg layer and on the presence of a wide band gap barrier at this interface. These results are explained based on the occupancy of the Mn energy band and how the occupancy can be altered due to carrier transfer at the GaMnN∕GaN:Mg interfaces. DA - 2004/10/25/ PY - 2004/10/25/ DO - 10.1063/1.1810216 VL - 85 IS - 17 SP - 3809-3811 SN - 1077-3118 ER - TY - JOUR TI - Ca-doped lead zirconate titanate thin film capacitors on base metal nickel on copper foil AU - Kim, T AU - Kingon, AI AU - Maria, JP AU - Croswell, RT T2 - JOURNAL OF MATERIALS RESEARCH DA - 2004/10// PY - 2004/10// DO - 10.1557/jmr.2004.0387 VL - 19 IS - 10 SP - 2841-2848 SN - 0884-2914 ER - TY - JOUR TI - AC coupled interconnect for dense 3-D ICs AU - Xu, J AU - Mick, S AU - Wilson, J AU - Luo, L AU - Chandrasekar, K AU - Erickson, E AU - Franzon, PD T2 - IEEE TRANSACTIONS ON NUCLEAR SCIENCE AB - This paper presents the potential application of AC coupled interconnect (ACCI) for dense three-dimensional (3-D) integrated circuits (ICs). The concept of inductive ACCI for 3-D ICs has been proposed. Combined with the "through vias" technology, inductive ACCI can provide small pitch vertical interconnects, as well as an excellent thermal solution for dense 3-D ICs. Transformer modeling and transceiver circuit design have also been investigated. Simulations predict that, for 20 /spl mu/m thinned die stacks coupled by a 100 /spl mu/m diameter transformer, the transceiver circuit fed with a 5 Gbps data stream consumes 14.5 mW power. DA - 2004/10// PY - 2004/10// DO - 10.1109/TNS.2004.834712 VL - 51 IS - 5 SP - 2156-2160 SN - 1558-1578 KW - AC coupled KW - inductive coupling KW - spiral inductor KW - three-dimensional integrated circuits (3-D ICs) KW - through vias KW - vertical interconnect ER - TY - JOUR TI - A voltage controlled oscillator using Barium strontium titanate (BST) thin film varactor AU - Victor, A AU - Nath, J AU - Ghosh, D AU - Boyette, B AU - Maria, JP AU - Steer, MB AU - Kingon, AI AU - Stauf, GT T2 - RAWCON: 2004 IEEE RADIO AND WIRELESS CONFERENCE, PROCEEDINGS AB - Barium strontium titanate (BST) has a field-dependent permittivity and can be used as a dielectric in voltage tunable capacitors or varactors. These BST-based varactors are passive devices and have significantly different properties compared to semiconductor varactors. A voltage tunable oscillator using a BST thin film varactor was designed and characterized. The frequency of oscillation varied from 34.8 MHz to 44.5 MHz (28% tuning) upon application of 7 V tuning voltage. The VCO gain was 1.38 MHz/V and the 2nd harmonic was over 23 dB below the fundamental throughout the tuning range. DA - 2004/// PY - 2004/// DO - 10.1109/rawcon.2004.1389079 SP - 91-94 KW - voltage controlled oscillator KW - varactors KW - ferroelectric films KW - harmonic distortion ER - TY - JOUR TI - A comparative analysis of structural risk minimization by support vector machines and nearest neighbor rule AU - Karacali, B AU - Ramanath, R AU - Snyder, WE T2 - PATTERN RECOGNITION LETTERS AB - Support vector machines (SVMs) are by far the most sophisticated and powerful classifiers available today. However, this robustness and novelty in approach come at a large computational cost. On the other hand, nearest neighbor (NN) classifiers provide a simple yet robust approach that is guaranteed to converge to a result. In this paper, we present a technique that combines these two classifiers by adopting a NN rule-based structural risk minimization classifier. Using synthetic and real data, the classification technique is shown to be more robust to kernel conditions with a significantly lower computational cost than conventional SVMs. Consequently, the proposed method provides a powerful alternative to SVMs in applications where computation time and accuracy are of prime importance. Experimental results indicate that the NNSRM formulation is not only computationally less expensive, but also much more robust to varying data representations than SVMs. DA - 2004/1/5/ PY - 2004/1/5/ DO - 10.1016/j.patrec.2003.09.002 VL - 25 IS - 1 SP - 63-71 SN - 1872-7344 KW - nearest neighbor KW - structural risk minimization KW - support vector machines KW - kernel operator KW - prototype selection ER - TY - JOUR TI - Woven fabric-based electrical circuits - Part II: Yarn and fabric structures to reduce crosstalk noise in woven fabric-based circuits AU - Dhawan, A AU - Ghosh, TK AU - Seyam, AM AU - Muth, JF T2 - TEXTILE RESEARCH JOURNAL AB - One important problem in electronic textiles is crosstalk and lack of signal integrity between conductive lines. Two significant advantages of electronic textiles over tradi tional circuit boards are flexibility and the ability to scale to large areas. Capacitive and inductive crosstalk is aggravated by long parallel conductors, and varies as the electronic textile is flexed into different configurations. This paper evaluates crosstalk between woven parallel conductors. Two new thread structures—coaxial and twisted pair copper threads—to minimize cross talk are developed and evaluated. Significant reductions in crosstalk are obtained with the coaxial and twisted pair thread structures when compared with bare copper threads or insulated conductive threads. DA - 2004/11// PY - 2004/11// DO - 10.1177/004051750407401103 VL - 74 IS - 11 SP - 955-960 SN - 1746-7748 ER - TY - JOUR TI - Voltage Variation Analysis for Site-Level PQ Assessment AU - Baran, M.E. AU - Kim, J. AU - Hart, D.G. AU - Lubkeman, D. AU - Lampley, G.C. AU - Newell, W.F. T2 - IEEE Transactions on Power Delivery AB - This paper investigates the challenges in developing a performance index that will reflect the level of power quality at a site based on the actual field data obtained from the site via power-quality (PQ) monitors. For the index, each observed voltage variation is assessed in terms of its potential to impact the customers served from the site. The paper considers the substation level PQ monitoring and adopts a procedure that is similar to one of the methods being proposed in the emerging IEEE guide 1564. DA - 2004/10// PY - 2004/10// DO - 10.1109/TPWRD.2004.829951 VL - 19 IS - 4 SP - 1956-1961 J2 - IEEE Trans. Power Delivery LA - en OP - SN - 0885-8977 UR - http://dx.doi.org/10.1109/tpwrd.2004.829951 DB - Crossref KW - power quality KW - power system monitoring KW - voltage variation index ER - TY - JOUR TI - Thermal elevation in the human eye and head due to the operation of a retinal prosthesis AU - Gosalia, K. AU - Weiland, J. AU - Humayun, M. AU - Lazzi, G. T2 - IEEE Transactions on Biomedical Engineering DA - 2004/// PY - 2004/// DO - 10.1109/TMBE.2004.827548 VL - 51 IS - 8 SP - 1469-1477 ER - TY - JOUR TI - The design and characterization of a novel piezoelectric transducer-based linear motor AU - Palmer, JA AU - Dessent, B AU - Mulling, JF AU - Usher, T AU - Grant, E AU - Eischen, JW AU - Kingon, AI AU - Franzon, PD T2 - IEEE-ASME TRANSACTIONS ON MECHATRONICS AB - Before microminiature robots can be realized, new direct drive micromotor systems must be developed. In this research, a linear motor system for a miniature jumping robot was desired. However, current systems must display better force/torque characteristics than is currently available. This paper deals with the design, construction, and testing, of a macro-scale, unidirectional, direct drive linear piezomotor that operates like an inchworm. It uses a parallel arrangement of unimorph piezoelectric transducers, in conjunction with passive mechanical latches, to perform work on a coil spring. Experimental results showed that the linear piezomotor achieved a maximum no-load velocity of 161 mm/s, and a blocked force of 14 N, at a drive signal frequency of 100 Hz. Thereafter, back slip in the latch assembly restricted the forward motion. Based on the results obtained with the macro-level linear piezomotor, it is concluded that smaller direct drive piezomotor designs based on unimorph piezoelectric transducers are achievable. System scalability will be addressed in a future publication. DA - 2004/6// PY - 2004/6// DO - 10.1109/TMECH.2004.828647 VL - 9 IS - 2 SP - 392-398 SN - 1941-014X KW - direct drive motors KW - linear piezomotor KW - passive latches KW - piezoelectric transducers ER - TY - CHAP TI - Storage-efficient stateless group key revocation AU - Wang, P. AU - Ning, P. AU - Reeves, D. S. T2 - Information security: 7th international conference, ISC 2004, Palo Alto, CA, USA, September 27-29, 2004: Proceedings A2 - K. Zhang, A2 - Zheng, Y. AB - Secure group communication relies on secure and robust distribution of group keys. A stateless group key distribution scheme is an ideal candidate when the communication channel is unreliable. Several stateless group key distribution schemes have been proposed. However, these schemes require all users store a certain number of auxiliary keys. The number of such keys increases as the group size grows. As a result, it is quite challenging to use these schemes when the users in a relatively large group have memory constraints. Thus, it is desirable to develop new schemes that can reduce the memory requirement. This paper introduces two novel stateless group key revocation schemes named key-chain tree (KCT) and layered key-chain tree (LKCT), which combine one-way key chains with a logical key tree. These schemes reduce the user storage requirements by trading off it with communication and computation costs. Specifically, these schemes can revoke any R users from a user group of size N by sending a key update message with at most 4R keys, while only requiring each user to store 2log N keys. CN - QA76.9 .A25 I85 2004 PY - 2004/// DO - 10.1007/978-3-540-30144-8_3 VL - 3225 SP - 25-38 PB - Berlin; New York: Springer SN - 3540232087 ER - TY - JOUR TI - Reliability of high-k dielectrics and its dependence on gate electrode and interfacial high-k bi-layer structure AU - Kim, YH AU - Choi, R AU - Jha, R AU - Lee, JH AU - Misra, V AU - Lee, JC T2 - MICROELECTRONICS RELIABILITY AB - In this work, we present the reliability of HfO 2 and how it depends on the barrier height and the nature of the bi-layer structure. We will also discuss how these factors lead to different charge fluence, charge-to-breakdown, and breakdown characteristics. It is found that the lower Weibull slope of high-k dielectrics is partially attributed to high charge fluence by the lower barrier height of high-k dielectrics, and a different nature of bi-layer structure. In addition, it has been found that there is distinct bi-modal defect generation rate for high-k/SiO 2 stack. A two-step breakdown process was clearly observed. Soft breakdown characteristics were dependent on the barrier heights. It is attributed to different charge fluence by different barrier heights. Charge-to-breakdown shows strong barrier height dependence. DA - 2004/// PY - 2004/// DO - 10.1016/j.microrel.2004.07.049 VL - 44 IS - 9-11 SP - 1513-1518 SN - 0026-2714 ER - TY - JOUR TI - Reductions in interface defects, D-it, by post oxidation plasma-assisted nitridation of GaN-SiO2 interfaces in MOS devices AU - Bae, C AU - Lucovsky, G T2 - MICROELECTRONIC ENGINEERING AB - This paper applies remote plasma processing techniques, remote plasma assisted oxidation (nitridation) RPAO(N) and RP enhanced chemical vapor deposition (RPECVD), developed originally for fabrication of Si MOS devices with deposited SiO2, Si3N4 and Si oxynitride alloys, to the formation of device-quality GaN MOS devices. Significant improvements in device performance for GaN–SiO2 interfaces are demonstrating by following an RPAO process step that forms the GaN–dielectric interface with an interfacial RPAN step prior to the deposition of the SiO2 dielectric film by RPECVD. On-line Auger electron spectroscopy is used to monitor interface bonding for different ordering of RPAO and RPAN process steps. DA - 2004/4// PY - 2004/4// DO - 10.1016/j.mee.2003.12.043 VL - 72 IS - 1-4 SP - 236-240 SN - 1873-5568 KW - semiconductor-dielectric interfaces KW - remote plasma processing KW - interfacial defects ER - TY - JOUR TI - Porphyrin architectures tailored for studies of molecular information storage AU - Carcel, CM AU - Laha, JK AU - Loewe, RS AU - Thamyongkit, P AU - Schweikart, KH AU - Misra, V AU - Bocian, DF AU - Lindsey, JS T2 - JOURNAL OF ORGANIC CHEMISTRY AB - A molecular approach to information storage employs redox-active molecules tethered to an electroactive surface. Zinc porphyrins tethered to Au(111) or Si(100) provide a benchmark for studies of information storage. Three sets of porphyrins have been synthesized for studies of the interplay of molecular design and charge-storage properties: (1) A set of porphyrins is described for probing the effect of surface attachment atom on electron-transfer kinetics. Each porphyrin bears a meso-CH2X group for surface attachment where X = OH, SAc, or SeAc. (2) A set of porphyrins is described for studying the effect of surface-charge density in monolayers. Each porphyrin bears a benzyl alcohol for surface attachment and three nonlinking meso substituents of a controlled degree of bulkiness. (3) A set of porphyrins is described that enables investigation of on-chip patterning of the electrolyte. Each porphyrin bears a formyl group distal to the surface attachment group for subsequent derivatization with a molecular entity that comprises the electrolyte. Taken together, this collection of molecules enables a variety of studies to elucidate design issues in molecular-based information storage. DA - 2004/10/1/ PY - 2004/10/1/ DO - 10.1021/jo0498260 VL - 69 IS - 20 SP - 6739-6750 SN - 0022-3263 ER - TY - JOUR TI - Multi-band Wigner function formulation of quantum transport AU - Unlu, MB AU - Rosen, B AU - Cui, HL AU - Zhao, PJ T2 - PHYSICS LETTERS A AB - A Wigner function representation of multi-band quantum transport theory is developed in this paper. The equations are derived using non-equilibrium Green's function formulation with the generalized Kadanoff-Baym ansatz and the multi-band $\bf{k.p}$ Hamiltonian including spin. The results are applied to a two-band resonant inter-band tunneling structure. DA - 2004/6/28/ PY - 2004/6/28/ DO - 10.1016/j.physleta.2004.05.022 VL - 327 IS - 2-3 SP - 230-240 SN - 1873-2429 KW - Wigner function equation KW - multi-band semiconductor systems ER - TY - JOUR TI - Mini-special issue on the 2003 IEEE MTT-S International Microwave Symposium AU - Steer, MB T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES DA - 2004/3// PY - 2004/3// DO - 10.1109/TMTT.2004.823530 VL - 52 IS - 3 SP - 741-742 SN - 0018-9480 ER - TY - JOUR TI - Maze exploration behaviors using an integrated evolutionary robotics environment AU - Nelson, AL AU - Grant, E AU - Galeotti, JM AU - Rhody, S T2 - ROBOTICS AND AUTONOMOUS SYSTEMS AB - This paper presents results generated with a new evolutionary robotics (ER) simulation environment and its complementary real mobile robot colony research test-bed. Neural controllers producing mobile robot maze searching and exploration behaviors using binary tactile sensors as inputs were evolved in a simulated environment and subsequently transferred to and tested on real robots in a physical environment. There has been a considerable amount of proof-of-concept and demonstration research done in the field of ER control in recent years, most of which has focused on elementary behaviors such as object avoidance and homing. Artificial neural networks (ANN) are the most commonly used evolvable controller paradigm found in current ER literature. Much of the research reported to date has been restricted to the implementation of very simple behaviors using small ANN controllers. In order to move beyond the proof-of-concept stage our ER research was designed to train larger more complicated ANN controllers, and to implement those controllers on real robots quickly and efficiently. To achieve this a physical robot test-bed that includes a colony of eight real robots with advanced computing and communication abilities was designed and built. The real robot platform has been coupled to a simulation environment that facilitates the direct wireless transfer of evolved neural controllers from simulation to real robots (and vice versa). We believe that it is the simultaneous development of ER computing systems in both the simulated and the physical worlds that will produce advances in mobile robot colony research. Our simulation and training environment development focuses on the definition and training of our new class of ANNs, networks that include multiple hidden layers, and time-delayed and recurrent connections. Our physical mobile robot design focuses on maximizing computing and communications power while minimizing robot size, weight, and energy usage. The simulation and ANN-evolution environment was developed using MATLAB. To allow for efficient control software portability our physical evolutionary robots (EvBots) are equipped with a PC-104-based computer running a custom distribution of Linux and connected to the Internet via a wireless network connection. In addition to other high-level computing applications, the mobile robots run a condensed version of MATLAB, enabling ANN controllers evolved in simulation to be transferred directly onto physical robots without any alteration to the code. This is the first paper in a series to be published cataloging our results in this field. DA - 2004/3/31/ PY - 2004/3/31/ DO - 10.1016/j.robot.2003.11.002 VL - 46 IS - 3 SP - 159-173 SN - 1872-793X KW - evolutionary robotics KW - Behavioral Robotics KW - evolutionary neural networks KW - Distributed Robotics KW - robot colonies ER - TY - JOUR TI - Infrared imaging learns from camera industry AU - Qi, H. R. AU - Snyder, W. E. T2 - Laser Focus World DA - 2004/// PY - 2004/// VL - 40 IS - 7 SP - 78- ER - TY - CHAP TI - Improving robustness of PGP keyrings by conflict detection AU - Jiang, Q. L. AU - Reeves, D. S. AU - Ning, P. T2 - Topics in cryptology, CT-RSA 2004 AB - Secure authentication frequently depends on the correct recognition of a user’s public key. When there is no certificate authority, this key is obtained from other users using a web of trust. If users can be malicious, trusting the key information they provide is risky. Previous work has suggested the use of redundancy to improve the trustworthiness of user-provided key information. In this paper, we address two issues not previously considered. First, we solve the problem of users who claim multiple, false identities, or who possess multiple keys. Secondly, we show that conflicting certificate information can be exploited to improve trustworthiness. Our methods are demonstrated on both real and synthetic PGP keyrings, and their performance is discussed. CN - QA76.9 .A25 C822 2004 PY - 2004/// DO - 10.1007/978-3-540-24660-2_16 VL - 2964 SP - 194-207 PB - Berlin; New York: Springer SN - 3540209964 ER - TY - JOUR TI - Improved Viterbi decoder metrics for two-stage detectors in DS-CDMA AU - Elezabi, A AU - Duel-Hallen, A T2 - IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS AB - Modified branch metrics are proposed for single-user Viterbi decoders in two-stage detectors for convolutionally-encoded code-division multiple-access (CDMA) systems with random spreading sequences. The modifications are based on modeling the residual multiple-access interference (RMAI) after subtractive interference cancellation as conditionally Gaussian with time-dependent variance, where the conditioning is on the time-varying user crosscorrelations. A novel estimate of the variance of the total RMAI is presented, and used in the proposed branch metrics. Significant performance gains are demonstrated over the Euclidean branch metric of the standard Viterbi decoder. DA - 2004/9// PY - 2004/9// DO - 10.1109/TWC.2004.833489 VL - 3 IS - 5 SP - 1399-1404 SN - 1558-2248 UR - http://dx.doi.org/10.1109/TWC.2004.833489 KW - code-division multiple-access (CDMA) KW - modified branch metrics KW - residual multiple-access interference (RMAI) KW - single-user Viterbi decoders KW - subtractive interference cancellation KW - time-dependent variance KW - two-stage detectors ER - TY - JOUR TI - High-frequency small-signal conductivity of hot electrons in nitride semiconductors AU - Sokolov, V. N. AU - Kim, K. W. AU - Kochelap, V. A. AU - Woolard, D. L. T2 - Applied Physics Letters AB - We investigate the small-signal conductivity of the electrons in group-III nitrides under a high steady-state electric field. The resulting calculation indicates a frequency dependence of the conductivity that is drastically different from that given by the Drude formula. A large and very fast response of the hot electrons in the nitrides is revealed. The complex conductivity is found to be finite up to the frequency of about 10 THz. For the fields above the threshold corresponding to the peak drift velocity, the calculation also predicts a frequency interval with a negative conductivity. A detailed analysis is provided on the field and frequency dependence of the dynamic conductivity at the high electric fields. DA - 2004/5/3/ PY - 2004/5/3/ DO - 10.1063/1.1738518 VL - 84 IS - 18 SP - 3630-3632 J2 - Appl. Phys. Lett. LA - en OP - SN - 0003-6951 1077-3118 UR - http://dx.doi.org/10.1063/1.1738518 DB - Crossref ER - TY - JOUR TI - Evolution of neural controllers for competitive game playing with teams of mobile robots AU - Nelson, AL AU - Grant, E AU - Henderson, TC T2 - ROBOTICS AND AUTONOMOUS SYSTEMS AB - In this work, we describe the evolutionary training of artificial neural network controllers for competitive team game playing behaviors by teams of real mobile robots. This research emphasized the development of methods to automate the production of behavioral robot controllers. We seek methods that do not require a human designer to define specific intermediate behaviors for a complex robot task. The work made use of a real mobile robot colony (EVolutionary roBOTs) and a closely coupled computer-based simulated training environment. The acquisition of behavior in an evolutionary robotics system was demonstrated using a robotic version of the game Capture the Flag. In this game, played by two teams of competing robots, each team tries to defend its own goal while trying to ‘attack’ another goal defended by the other team. Robot neural controllers relied entirely on processed video data for sensing of their environment. Robot controllers were evolved in a simulated environment using evolutionary training algorithms. In the evolutionary process, each generation consisted of a competitive tournament of games played between the controllers in an evolving population. Robot controllers were selected based on whether they won or lost games in the course of a tournament. Following a tournament, the neural controllers were ranked competitively according to how many games they won and the population was propagated using a mutation and replacement strategy. After several hundred generations, the best performing controllers were transferred to teams of real mobile robots, where they exhibited behaviors similar to those seen in simulation including basic navigation, the ability to distinguish between different types of objects, and goal tending behaviors. DA - 2004/3/31/ PY - 2004/3/31/ DO - 10.1016/j.robot.2004.01.001 VL - 46 IS - 3 SP - 135-150 SN - 1872-793X KW - evolutionary robotics KW - robot colonies KW - mobile robots KW - evolutionary neural computing KW - behavioral robotics ER - TY - JOUR TI - Clustering effects on discontinuous gold film NanoCells AU - Seminario, JM AU - Ma, YF AU - Agapito, LA AU - Yan, LM AU - Araujo, RA AU - Bingi, S AU - Vadlamani, NS AU - Chagarlamudi, K AU - Sudarshan, TS AU - Myrick, ML AU - Colavita, PE AU - Franzon, PD AU - Nackashi, DP AU - Cheng, L AU - Yao, YX AU - Tour, JM T2 - JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY AB - Reproducible negative differential resistance (NDR)-like switching behavior is observed in NanoCells. This behavior is attributed to the formation of filaments and clusters between the discontinuous gold films. Control experiments are performed by self-assembly of insulating molecules between the gold islands and conducting molecules on these islands. Additional control experiments are performed by removing the filaments and clusters between islands using a piranha bath. The results are consistent with theoretical predictions and extend the domain of molecular electronics based in organic molecules to include nanosized clusters as active units. This facilitates a scenario where synthetically accessible organic molecules, with defined characteristics, can be adjusted by metallic nanoclusters as an in situ fine-tuning element, able to compensate for the lack of addressing in the nanosize regime. DA - 2004/9// PY - 2004/9// DO - 10.1166/jnn.2004.104 VL - 4 IS - 7 SP - 907-917 SN - 1533-4899 KW - negative differential resistance KW - NanoCell KW - clustering KW - filamentary formation KW - discontinuous gold film KW - interlinking molecule KW - self-assembling KW - ab initio KW - molecular dynamics KW - density functional theory KW - nanotechnology KW - molecular electronics KW - nanoelectronics ER - TY - CHAP TI - Certificate recommendations to improve the robustness of web of trust AU - Jiang, Q. L. AU - Reeves, D. S. AU - Ning, P. T2 - Information security: 7th international conference, ISC 2004, Palo Alto, CA, USA, September 27-29, 2004: Proceedings A2 - K. Zhang, A2 - Zheng, Y. AB - Users in a distributed system establish webs of trust by issuing and exchanging certificates amont themselves. This approach does not require a central, trusted keyserver. The distributed web of trust, however, is susceptible to attack by malicious users, who may issue false certificates. In this work, we propose a method for generating certificate recommendations. These recommendations guide the users in creating webs of trust that are highly robust to attacks. To accomplish this we propose a heuristic method of graph augmentation for the certificate graph, and show experimentally that it is close to optimal. We also investigate the impact of user preferences and non-compliance with these recommendations, and demonstrate that our method helps identify malicious users if there are any. CN - QA76.9 .A25 I85 2004 PY - 2004/// DO - 10.1007/978-3-540-30144-8_25 VL - 3225 SP - 292-303 PB - Berlin; New York: Springer SN - 3540232087 ER - TY - PAT TI - Vertical field effect transistors including conformal monocrystalline silicon layer on trench sidewall AU - Zhang, Z. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - JOUR TI - Modification and use of DRAINMOD to evaluate a lagoon effluent land application system AU - Ha, Z. AU - Evans, R. O. AU - Luo, W. AU - Skaggs, R. W. T2 - Transactions of the ASAE AB - Traditionally, lagoon design has considered waste inflow, sludge accumulation, individual event rainfallassociated with the 25-year, 24-hour storm, and sufficient temporary storage to handle excess rainfall during non-irrigationperiods. Excess rainfall was defined as the average or normal rainfall in excess of evaporation during the non-irrigation(drawdown) period. North Carolina experienced a series of tropical storms and hurricanes in 1995 that resulted in severallagoon overtoppings; however, none of the storms individually satisfied the 25-year, 24-hour criterion. These storms raisedquestions as to whether the 25-year, 24-hour criterion presented the appropriate design constraint to prevent lagoonovertopping or whether the cumulative impact of prolonged rainy periods (referred to herein as chronic rainfall) was agreater threat. To evaluate the validity of existing lagoon design criteria and emergency action measures proposed by theNorth Carolina Soil and Water Conservation Commission, the irrigation component of the field hydrology model DRAINMODwas modified to consider animal waste lagoon constraints of chronic rainfall, crop nitrogen utilization, and emergency lagoonoperational measures. The modified DRAINMOD was used to evaluate lagoon design and operational guidelines in effectin eastern North Carolina at the time of the 1995 lagoon breaches and the proposed 1999 emergency measures. Modelsimulation results showed that prolonged wet periods in the winter that result in high moisture surplus are the most likely causeof excessively high lagoon stage or overflow. To minimize the occurrence of elevated lagoon stage and eliminate the risk ofoverflow, model results also showed that the design temporary storage criterion should be increased to account for chronicrainfall excess between drawdown periods. Intense storms with short durations, such as the catastrophic design (25-year,24-hour) storm, mainly occurred in the summer and usually posed no risks to lagoon overflow because these events typicallyoccurred at a time when lagoons were traditionally drawn down to their lowest allowable stage. Using a constant averagenitrogen concentration for lagoon wastewater resulted in fewer irrigation applications, which in turn resulted in morefrequent high lagoon stage and more overflows. Lagoon spills resulting from extreme weather conditions could be avoidedby applying wastewater more frequently and temporarily suspending the crop nitrogen limit in wet years without exceedingsoil hydraulic limits. DA - 2004/// PY - 2004/// DO - 10.13031/2013.15869 VL - 47 IS - 1 SP - 47-58 ER - TY - JOUR TI - Distributed biasing of differential RF circuits AU - Fathelbab, WM AU - Steer, MB T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - A distributed balun is presented as an alternative to inductor-based biasing of active differential circuits. The new scheme has broad bandwidth with low loss and is suited to broad-band multifunctional RF and microwave circuits. Additionally, the distributed biasing circuit discriminates between differential and common-mode signals leading to high common-mode rejection. Measured gains, centered at 580 MHz, of a selected pseudodifferential amplifier using the new biasing circuit confirm the underlying theory. DA - 2004/5// PY - 2004/5// DO - 10.1109/TMTT.2004.827048 VL - 52 IS - 5 SP - 1565-1572 SN - 1557-9670 KW - balun KW - broad-band biasing KW - differential amplifier ER - TY - JOUR TI - Bandwidth provisioning and pricing for networks with multiple classes of service AU - Fulp, EW AU - Reeves, DS T2 - COMPUTER NETWORKS AB - Network service providers purchase large point-to-point connections from network owners, then offer individual users network access at a price. Appropriately provisioning (purchasing) and allocating (pricing) connections remains a difficult problem due to increasing demands and network dynamics. However, connection management is more complex with the deployment of Quality of Service (QoS). This paper describes a scalable connection management strategy for QoS-enabled networks. The management technique maximizes profit, while reducing blocking experienced by users. Important issues regarding demand estimation, connection duration, and pricing intervals, are addressed and analyzed. Simulation results are also provided to demonstrate the viability of the proposed system. DA - 2004/9/16/ PY - 2004/9/16/ DO - 10.1016/j.comnet.2004.03.018 VL - 46 IS - 1 SP - 41-52 SN - 1872-7069 KW - connection management KW - SLA KW - DiffServ KW - bandwidth pricing KW - microeconomics ER - TY - JOUR TI - A nonlinear entropic variational model for image filtering AU - Ben Hamza, A AU - Krim, H AU - Zerubia, J T2 - EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING AB - We propose an information-theoretic variational filter for image denoising. It is a result of minimizing a functional subject to some noise constraints, and takes a hybrid form of a negentropy variational integral for small gradient magnitudes and a total variational integral for large gradient magnitudes. The core idea behind this approach is to use geometric insight in helping to construct regularizing functionals and avoiding a subjective choice of a prior in maximum a posteriori estimation. Illustrative experimental results demonstrate a much improved performance of the approach in the presence of Gaussian and heavy-tailed noise. DA - 2004/11/15/ PY - 2004/11/15/ DO - 10.1155/S1110865704407197 VL - 2004 IS - 16 SP - 2408-2422 SN - 1687-0433 KW - MAP estimation KW - variational methods KW - robust statistics KW - differential entropy KW - gradient descent flows KW - image denoising ER - TY - JOUR TI - A Markov chain sequence generator for power macromodeling AU - Liu, X AU - Papaefthymiou, MC T2 - IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS AB - In this paper, we present a novel sequence generator based on a Markov chain (MC) model. Specifically, we formulate the problem of generating a sequence of vectors with given average input probability p, average transition density d, and spatial correlation s as a transition matrix computation problem, in which the matrix elements are subject to constraints derived from the specified statistics. We also give a practical heuristic that computes such a matrix and generates a sequence of l n-bit vectors in O(nl+n/sup 2/) time. Derived from a strongly mixing MC, our generator yields binary vector sequences with accurate statistics, high uniformity, and high randomness. Experimental results show that our sequence generator can cover more than 99% of the parameter space. Sequences of 2000 48-bit vectors are generated in less than 0.05 s, with average deviations of the signal statistics p,d, and s equal to 1.6%, 1.8%, and 2.8%, respectively. Our generator enables the detailed study of power macromodeling. Using our tool and the ISCAS'85 benchmark circuits, we have assessed the sensitivity of power dissipation to the three input statistics p,d, and s. Our investigation reveals that power is most sensitive to transition density, while only occasionally exhibiting high sensitivity to signal probability and spatial correlation. Our experiments also show that input signal imbalance can cause estimation errors as high as 100% in extreme cases, although errors are usually within 25%. DA - 2004/7// PY - 2004/7// DO - 10.1109/TCAD.2004.829819 VL - 23 IS - 7 SP - 1048-1062 SN - 1937-4151 KW - power estimation KW - power model KW - signal statistics KW - vector generation ER - TY - JOUR TI - Woven fabric-based electrical circuits - Part I: Evaluating interconnect methods AU - Dhawan, A. AU - Seyam, A. M. AU - Ghosh, T. K. AU - Muth, J. F. T2 - Textile Research Journal AB - In recent years, a new area of research has emerged on textile-based electronics, called "electrotextiles." Most of the ongoing research in electrotextiles is driven by the motiva tion of creating multifunctional fiber assemblies that can sense, actuate, communicate, compute, etc. This paper discusses the development of fabric-based electrical circuits by interlacing conducting and nonconducting threads 2 into woven textile structures. Wired interconnections of different devices attached to the conducting elements of these circuits are made by arranging and weaving conductive threads so that they follow desired electrical circuit designs. In a woven electrically conductive network, routing of electrical signals is achieved by the formation of effective electrical interconnects and disconnects. Resistance welding is identified as one of the most effective means of producing crossover point interconnects and disconnects. Interconnects are evaluated by measuring the DC resistance associated with the crossover points of conducting threads. DA - 2004/// PY - 2004/// DO - 10.1177/004051750407401011 VL - 74 IS - 10 SP - 913-919 ER - TY - JOUR TI - Use of the FDTD thin-strut formalism for biomedical telemetry coil designs AU - Schmidt, S AU - Lazzi, G T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - The finite-difference time-domain (FDTD) method extended by thin-strut formalism was used to study the current coupling between rectangular coils for use in biomedical telemetry links. Further, a new stability condition, different from the Courant-Friedrichs-Lewy stability limit, was derived for the thin-strut method. Results obtained for varying coil sizes and distances of separation show that the thin-strut FDTD formulation, applied to the calculation of current coupling between telemetry coils, is in closer agreement to the analytical approximation than is the standard FDTD code. These results indicate that the thin-strut method is a promising method for the study and the design of coils for telemetry links between implantable and external devices. DA - 2004/8// PY - 2004/8// DO - 10.1109/TMTT.2004.832019 VL - 52 IS - 8 SP - 1952-1956 SN - 1557-9670 KW - biomedical telemetry KW - coils KW - electromagnetic coupling KW - finite-difference time-domain (FDTD) methods KW - numerical stability KW - thin-strut formulation ER - TY - JOUR TI - Use of micromachined probes for the recording of cardiac electrograms in isolated heart tissues AU - Kim, CS AU - Ufer, S AU - Seagle, CM AU - Engle, CL AU - Nagle, HT AU - Johnson, TA AU - Cascio, WE T2 - BIOSENSORS & BIOELECTRONICS AB - Micromachined probes, with iridium (Ir) microelectrodes on silicon shanks, were evaluated to assess their suitability for cardiac electrogram recording. The electrochemical activation (anodic oxidation) procedure for the circular Ir microelectrode was investigated using the square wave potential according to the electrode size, number of cycles, and cathodic-anodic potential level of the square wave. Increase in the charge storage capacity was pronounced either in smaller electrodes or with higher potential level of the square wave. The electrode impedance reduced in a similar manner with increasing number of cycle irrespective of the electrode size. With either lower potential level (-0.70/+0.60 V) or smaller number of cycle (200 cycles) than those for the activation of stimulating electrode, the likelihood of overactivation of the recording microelectrode can be minimized. These anodic IrOx film (AIROF) microelectrodes were used for the recording of extracellular electrograms in two different ex vivo cardiac tissue preparations. A single-shank microprobe was applied to the left ventricle of a mouse heart. Both the spontaneous and paced transmural responses propagating between epicardium and endocardium were obtained. Longitudinal cardiac wavefronts propagating along the rabbit papillary muscle were also recorded with a unique multiple-shank design. The measured mean amplitude and the propagation velocity of the extracellular voltage were 12.2 +/- 1.8 mV and 58.9 +/- 2.2 cm/s, respectively (n = 27). These microprobes with precisely defined electrode spacing make a useful tool for the spatial and temporal mapping of electrical properties in isolated heart tissues ex vivo. DA - 2004/4/15/ PY - 2004/4/15/ DO - 10.1016/j.bios.2003.10.011 VL - 19 IS - 9 SP - 1109-1116 SN - 1873-4235 KW - iridium oxide KW - microelectrode KW - activation KW - papillary muscle KW - ventricle KW - cardiac mapping ER - TY - JOUR TI - Special issue on medical applications and biological effects of RF/microwaves - Guest editorial AU - Lazzi, G AU - Gandhi, OP AU - Ueno, S T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES DA - 2004/8// PY - 2004/8// DO - 10.1109/TMTT.2004.832682 VL - 52 IS - 8 SP - 1853-1855 SN - 0018-9480 ER - TY - JOUR TI - Porphyrins bearing mono or tripodal benzylphosphonic acid tethers for attachment to oxide surfaces AU - Loewe, RS AU - Ambroise, A AU - Muthukumaran, K AU - Padmaja, K AU - Lysenko, AB AU - Mathur, G AU - Li, QL AU - Bocian, DF AU - Misra, V AU - Lindsey, JS T2 - JOURNAL OF ORGANIC CHEMISTRY AB - The ability to attach redox-active molecules to oxide surfaces in controlled architectures (distance, orientation, packing density) is essential for the design of a variety of molecular-based information storage devices. We describe the synthesis of a series of redox-active molecules wherein each molecule bears a benzylphosphonic acid tether. The redox-active molecules include zinc porphyrins, a cobalt porphyrin, and a ferrocene-zinc porphyrin. An analogous tripodal tether has been prepared that is based on a tris[4-(dihydroxyphosphorylmethyl)phenyl]-derivatized methane. A zinc porphyrin is linked to the methane vertex by a 1,4-phenylene unit. The tripodal systems are designed to improve monolayer stability and ensure vertical orientation of the redox-active porphyrin on the electroactive surface. For comparison purposes, a zinc porphyrin bearing a hexylphosphonic acid tether also has been prepared. The synthetic approaches for introduction of the phosphonic acid group include derivatization of a bromoalkyl porphyrin or use of a dimethyl or diethyl phosphonate substituted precursor in a porphyrin-forming reaction. The latter approach makes use of dipyrromethane building blocks bearing mono or tripodal dialkyl phosphonate groups. The zinc porphyrin-tripodal compound bearing benzylphosphonic acid legs tethered to a SiO(2) surface (grown on doped Si) was electrically well-behaved and exhibited characteristic porphyrin oxidation/reduction waves. Collectively, a variety of porphyrinic molecules can now be prepared with tethers of different length, composition, and structure (mono or tripodal) for studies of molecular-based information storage on oxide surfaces. DA - 2004/3/5/ PY - 2004/3/5/ DO - 10.1021/jo034946d VL - 69 IS - 5 SP - 1453-1460 SN - 1520-6904 ER - TY - JOUR TI - Porphyrins bearing arylphosphonic acid tethers for attachment to oxide surfaces AU - Muthukumaran, K AU - Loewe, RS AU - Ambroise, A AU - Tamaru, SI AU - Li, QL AU - Mathur, G AU - Bocian, DF AU - Misra, V AU - Lindsey, JS T2 - JOURNAL OF ORGANIC CHEMISTRY AB - Synthetic molecules bearing phosphonic acid groups can be readily attached to oxide surfaces. As part of a program in molecular-based information storage, we have developed routes for the synthesis of diverse porphyrinic compounds bearing phenylphosphonic acid tethers. The routes enable (1) incorporation of masked phosphonic acid groups in precursors for use in the rational synthesis of porphyrinic compounds and (2) derivatization of porphyrins with masked phosphonic acid groups. The precursors include dipyrromethanes, monoacyldipyrromethanes, and diacyldipyrromethanes. The tert-butyl group has been used to mask the dihydroxyphosphoryl substituent. The di-tert-butyloxyphosphoryl unit is stable to the range of conditions employed in syntheses of porphyrins and multiporphyrin arrays yet can be deprotected under mild conditions (TMS-Cl/TEA or TMS-Br/TEA in refluxing CHCl3) that do not cause demetalation of zinc or magnesium porphyrins. The porphyrinic compounds that have been prepared include (1) A3B-, trans-AB2C-, and ABCD-porphyrins that bear a single phenylphosphonic acid group, (2) a trans-A2B2-porphyrin bearing two phenylphosphonic acid groups, (3) a chlorin that bears a single phenylphosphonic acid group, and (4) a porphyrin dyad bearing a single phenylphosphonic acid group. For selected porphyrin-phosphonic acids, the electrochemical characteristics have been investigated for molecules tethered to SiO2 surfaces grown on doped Si. The voltammetric behavior indicates that the porphyrin-phosphonic acids form robust, electrically well-behaved monolayers on the oxide surface. DA - 2004/3/5/ PY - 2004/3/5/ DO - 10.1021/jo034945l VL - 69 IS - 5 SP - 1444-1452 SN - 0022-3263 ER - TY - JOUR TI - Low-temperature preparation of GaN-SiO2 interfaces with low defect density. II. Remote plasma-assisted oxidation of GaN and nitrogen incorporation\ AU - Bae, C AU - Lucovsky, G T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - Low-temperature remote plasma-assisted oxidation and nitridation processes for interface formation and passivation have been extended from Si and SiC to GaN. The initial oxidation kinetics and chemical composition of thin interfacial oxide were determined from analysis of on-line Auger electron spectroscopy features associated with Ga, N, and O. The plasma-assisted oxidation process is self-limiting with power-law kinetics similar to those for the plasma-assisted oxidation of Si and SiC. Oxidation using O2∕He plasma forms nearly pure GaOx, and oxidation using 1% N2O in N2 forms GaOxNy with small nitrogen content, ∼4–7at.%. The interface and dielectric layer quality was investigated using fabricated GaN metal-oxide-semiconductor capacitors. The lowest density of interface states was achieved with a two-step plasma-assisted oxidation and nitridation process before SiO2 deposition. DA - 2004/// PY - 2004/// DO - 10.1116/1.1807411 VL - 22 IS - 6 SP - 2411-2418 SN - 1520-8559 ER - TY - JOUR TI - Low-temperature preparation of GaN-SiO2 interfaces with low defect density. I. Two-step remote plasma-assisted oxidation-deposition process AU - Bae, C AU - Lucovsky, G T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - In previous studies, device-quality Si-SiO2 interfaces and dielectric bulk films (SiO2) were prepared using a two-step process: (i) remote plasma-assisted oxidation (RPAO) to form a superficially interfacial oxide (∼0.6nm) and (ii) remote plasma-enhanced chemical vapor deposition (RPECVD) to deposit the oxide film. The same approach has been applied to the GaN-SiO2 system. Without an RPAO step, subcutaneous oxidation of GaN takes place during RPECVD deposition of SiO2, and on-line Auger electron spectroscopy indicates a ∼0.7-nm subcutaneous oxide. The quality of the interface and dielectric layer with/without RPAO process has been investigated by fabricated GaN metal-oxide-semiconductor capacitors. Compared to single-step SiO2 deposition, significantly reduced defect state densities are obtained at the GaN-SiO2 interface by independent control of GaN-GaOx interface formation by RPAO and SiO2 deposition by RPECVD. DA - 2004/// PY - 2004/// DO - 10.1116/1.1807396 VL - 22 IS - 6 SP - 2402-2410 SN - 1520-8559 ER - TY - JOUR TI - Investigation of a microwave data telemetry link for a retinal prosthesis AU - Gosalia, K AU - Lazzi, G AU - Humayun, M T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - In this paper, we investigate a novel approach of establishing a data telemetry link for a dual-unit retinal prosthesis at microwave frequencies (1.45 and 2.45 GHz) using a pair of microstrip patch antennas. Appropriately sized extraocular (25/spl times/25 mm) and intraocular (6/spl times/6 mm) antennas are designed to operate at both the frequencies using the finite-difference time-domain method, and the coupling between them is examined computationally in the presence of a 0.25-mm resolution human-head model. Good agreement between numerical and experimental coupling results is shown and it is observed that the eyeball acts as a dielectric lens for the implanted antenna, thus improving the coupling between the extraocular and intraocular antennas. Specific absorption rate (SAR) computations are also performed at both the frequencies, and the peak 1-g SAR value is calculated. Detailed analysis of the design issues of the antennas, results of the numerical and experimental coupling measurements, and SAR calculations are presented. DA - 2004/8// PY - 2004/8// DO - 10.1109/TMTT.2004.832007 VL - 52 IS - 8 SP - 1925-1933 SN - 1557-9670 KW - antenna coupling KW - data telemetry KW - dosimetry KW - retinal prosthesis ER - TY - JOUR TI - Electron trapping in metal-insulator-semiconductor structures on n-GaN with SiO2 and Si3N4 dielectrics AU - Bae, C AU - Krug, C AU - Lucovsky, G T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - Electron trapping in Al-gate n-GaN∕nitrided-thin-Ga2O3∕SiO2 and n-GaN∕Si3N4 MIS capacitors was evaluated by capacitance-voltage (C–V) measurements. Significant positive flatband voltage shift (ΔVfb) was observed with increasing starting dc bias in the C–V measurements. For similar equivalent oxide thickness and under the same C–V measurement conditions, ΔVfb in the nitride was 3–10 times larger than in the oxide samples. It is suggested that flatband voltage shifts are due to border traps in SiO2 and to interface and bulk traps in Si3N4 samples. DA - 2004/// PY - 2004/// DO - 10.1116/1.1806439 VL - 22 IS - 6 SP - 2379-2383 SN - 1520-8559 ER - TY - JOUR TI - Effect of post-metallization annealing for alternative gate stack devices AU - Kim, I AU - Han, SK AU - Osburn, CM T2 - JOURNAL OF THE ELECTROCHEMICAL SOCIETY AB - The effect of the post-metallization annealing of devices having or dielectrics and poly-Si or TaN gate electrodes was studied. Forming gas (10% annealing at 400°C enhanced drive current and channel mobility of devices having 1.2 nm gate dielectrics, by eliminating interface states. Post-metal annealing in 10% for 1.2 nm gate dielectrics resulted in larger enhancements in drive current and device channel mobility than forming gas annealing. Similar enhancements of the device characteristics were observed in (300 mV shift in both flatband and threshold voltage) and (200 mV shift only in threshold voltage) materials. Annealing in pure nitrogen was found to degrade the dielectric quality of including a decrease in device current and 50% lower capacitance. © 2004 The Electrochemical Society. All rights reserved. DA - 2004/2// PY - 2004/2// DO - 10.1149/1.1636181 VL - 151 IS - 2 SP - F29-F35 SN - 1945-7111 ER - TY - JOUR TI - Asynchronous software thread integration for efficient software implementations of embedded communication protocol controllers AU - Kumar, NJ AU - Shivshankar, S AU - Dean, AG T2 - ACM SIGPLAN NOTICES AB - The overhead of context-switching limits efficient scheduling of multiple concurrent threads on a uniprocessor when real-time requirements exist. Existing software thread integration (STI) methods reduce context switches, but only provide synchronous thread progress within integrated functions. For the remaining, non-integrated portions of the secondary threads to run and avoid starvation, the primary thread must have adequate amounts of coarse-grain idle time (longer than two context-switches). We have developed asynchronous software thread integration (ASTI) methods which address starvation through the efficient use of coroutine calls and integration. ASTI allows threads to make independent progress efficiently and reduces the number of context switches needed through integration.Software-implemented protocol controllers are crippled by this problem; the primary thread "bit-bangs" each bit of a message onto or off of the bus, leaving only fragments of idle time shorter than a bit time. This fragmented time may be too short to recover through context switching, so only the primary thread can execute during message transmission or reception, slowing the secondary threads and potentially making them miss their deadlines. ASTI simplifies the implementation of embedded communication protocols on low-cost, moderate speed (1 - 100 MHz, 8- and 16-bit) microcontrollers. We demonstrate ASTI by replacing a standard automotive communication protocol controller (J1850) with software and generic hardware. Secondary thread performance improves significantly when compared with a traditional interrupt-based software approach. DA - 2004/7// PY - 2004/7// DO - 10.1145/998300.997170 VL - 39 IS - 7 SP - 37-46 SN - 1558-1160 KW - algorithms KW - design KW - experimentation KW - asynchronous software thread integration KW - hardware to software migration KW - fine-grain concurrency KW - software-implemented communication protocol controllers KW - J1850 ER - TY - JOUR TI - A simple mechanism for detecting ineffectual instructions in slipstream processors AU - Koppanalil, JJ AU - Rotenberg, E T2 - IEEE TRANSACTIONS ON COMPUTERS AB - A slipstream processor accelerates a program by speculatively removing repeatedly ineffectual instructions. Detecting the roots of ineffectual computation: unreferenced writes, nonmodifying writes, and correctly predicted branches, is straightforward. On the other hand, detecting ineffectual instructions in the backward slices of these root instructions currently requires complex back-propagation circuitry. We observe that, by logically monitoring the speculative program (instead of the original program), back-propagation can be reduced to detecting unreferenced writes. That is, once root instructions are actually removed, instructions at the next higher level in the backward slice become newly exposed unreferenced writes in the speculative program. This new algorithm, called implicit back-propagation, eliminates complex hardware and achieves an average performance improvement of 11.8 percent, only marginally lower than the 12.3 percent improvement achieved with explicit back-propagation. We further simplify the hardware component by electing not to detect ineffectual memory writes, focusing only on ineffectual register writes. A minimal implementation consisting of only a register-indexed table (similar to an architectural register file) achieves a good balance between complexity and performance (11.2 percent average performance improvement with implicit back-propagation and without detection of ineffectual memory writes). DA - 2004/4// PY - 2004/4// DO - 10.1109/TC.2004.1268397 VL - 53 IS - 4 SP - 399-413 SN - 1557-9956 KW - microarchitecture KW - multithreading KW - chip multiprocessor KW - slipstream KW - preexecution ER - TY - JOUR TI - Synthesis of porphyrins bearing hydrocarbon tethers and facile covalent attachment to Si(100) AU - Liu, ZM AU - Yasseri, AA AU - Loewe, RS AU - Lysenko, AB AU - Malinovskii, VL AU - Zhao, Q AU - Surthi, S AU - Li, QL AU - Misra, V AU - Lindsey, JS AU - Bocian, DF T2 - JOURNAL OF ORGANIC CHEMISTRY AB - The use of redox-active molecules as the active storage elements in memory chips requires the ability to attach the molecules to an electroactive surface in a reliable and robust manner. To explore the use of porphyrins tethered to silicon via carbosilane linkages, 17 porphyrins have been synthesized. Fourteen porphyrins bear a tether at a single meso site, and three porphyrins bear functional groups at two β sites for possible two-point attachment. Two high-temperature processing methods (400 °C under inert atmosphere) have been developed for rapid (minutes), facile covalent attachment to Si platforms. The high-temperature processing conditions afford attachment either by direct deposition of a dilute solution (1 μM−1 mM) of the porphyrin sample onto the Si substrate or sublimation of a neat sample onto the Si substrate. The availability of this diverse collection of porphyrins enables an in-depth examination of the effects of the tether (length, composition, terminal functional group, number of tethers) and steric bulk of nonlinking substituents on the information-storage properties of the porphyrin monolayers obtained upon attachment to silicon. Attachment proceeds readily with a wide variety of hydrocarbon tethers, including 2-(trimethylsilyl)ethynyl, vinyl, allyl, or 3-butenyl directly appended to the porphyrin and iodo, bromomethyl, 2-(trimethylsilyl)ethynyl, ethynyl, vinyl, or allyl appended to the 4-position of a meso-phenyl ring. No attachment occurs with substituents such as phenyl, p-tolyl, mesityl, or ethyl. Collectively, the studies show that the high-temperature attachment procedure (1) has broad scope encompassing diverse functional groups, (2) tolerates a variety of arene substituents, and (3) does not afford indiscriminate attachment. The high-temperature processing conditions are ideally suited for use in fabrication of hybrid molecular/semiconductor circuitry. DA - 2004/8/20/ PY - 2004/8/20/ DO - 10.1021/jo049439q VL - 69 IS - 17 SP - 5568-5577 SN - 0022-3263 ER - TY - JOUR TI - Experimental studies of the formation process and morphologies of carbon nanotubes with bamboo mode structures AU - Wang, YY AU - Tang, GY AU - Koeck, FM AU - Brown, B AU - Garguilo, JM AU - Nemanich, RJ T2 - DIAMOND AND RELATED MATERIALS AB - Carbon nanotubes (CNT) were synthesized by microwave plasma chemical vapor deposition, and the formation process and morphologies of bamboo mode structures were systematically analyzed. Thin films of Fe on Si substrates were used as the catalyst, and the CNT films were characterized with electron microscopy, Raman spectroscopy, and Auger electron spectroscopy. For growth up to 15 min, the films grow with vertically aligned CNT with evidence of amorphous carbon at the top surface. For longer growth times the films exhibit a layer of amorphous carbon and a CNT mat on top of the aligned carbon nanotube ‘forest.’ Transmission electron microscopy measurements displayed multiwalled CNT with bamboo structure and encapsulated tips some of which contained catalyst particles. Two kinds of bamboo mode structures were observed: cone shaped, and cylindrical. The results indicate that the CNT growth is predominantly of the base growth mode, and the formation of the compartments was attributed to the difference in the bulk and surface diffusion of carbon species at the catalyst. DA - 2004/// PY - 2004/// DO - 10.1016/j.diamond.2004.01.009 VL - 13 IS - 4-8 SP - 1287-1291 SN - 0925-9635 KW - multiwalled carbon nanotubes KW - bamboo mode KW - formation process KW - morphologies ER - TY - JOUR TI - A capacitance-based methodology for work function extraction of metals on high-kappa AU - Jha, R AU - Gurganos, J AU - Kim, YH AU - Choi, R AU - Lee, J AU - Misra, V T2 - IEEE ELECTRON DEVICE LETTERS AB - This letter presents a methodology to accurately extract the work function of metal electrodes on high-/spl kappa/ dielectrics with various charge distributions. A mathematical analysis including sources of errors was used to study the effect of charge distribution in gate dielectric stacks on the flatband voltage of the device. The calculations are verified by experimental results obtained for Ru-Ta alloys on HfO/sub 2/ and SiO/sub 2/ gate dielectric stacks. It is shown that accounting for the appropriate charge model is imperative for accurate calculation of workfunction on high-/spl kappa//SiO/sub 2/ gate dielectric stacks. DA - 2004/6// PY - 2004/6// DO - 10.1109/LED.2004.829032 VL - 25 IS - 6 SP - 420-423 SN - 1558-0563 KW - dual-gate CMOS KW - Fermi-level pinning KW - gate electrodes KW - HfO2 KW - high-kappa charges KW - metal gates KW - workfunction extraction ER - TY - JOUR TI - Toroidal inductors for radio-frequency integrated circuits AU - Liu, WY AU - Suryanarayanan, J AU - Nath, J AU - Mohammadi, S AU - Katehi, LPB AU - Steer, MB T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - Toroidal inductors achieve low loss by constraining magnetic flux to a well-defined path and away from ground planes and semiconducting substrates. This paper presents a micromachined implementation of the toroidal inductor, with focus primarily on microwave integrated circuits on a low-resistivity silicon wafer achieving a Q of 22 and a self-resonant frequency greater than 10 GHz. A verified analytic model is developed. DA - 2004/2// PY - 2004/2// DO - 10.1109/TMTT.2003.822019 VL - 52 IS - 2 SP - 646-654 SN - 1557-9670 KW - inductor KW - micromachining KW - monolithic microwave integrated circuit (MMIC) KW - radio-frequency integrated circuit (RFIC) KW - toroidal inductor ER - TY - BOOK TI - Network management: Concepts and practice, a hands-on approach AU - Burke, J. R. CN - TK5105.5 .B866 2004 DA - 2004/// PY - 2004/// PB - Upper Saddle River, NJ: Pearson Education SN - 0130329509 ER - TY - PAT TI - Methods of forming nano-scale electronic and optoelectronic devices using non-photolithographically defined nano-channel templates AU - Zhang, Z. AU - Misra, V. AU - Bedair, S. M. A. AU - Ozturk, M. C2 - 2004/// DA - 2004/// PY - 2004/// ER - TY - CHAP TI - Experimental analysis of the SABUL congestion control algorithm AU - Oothongsap, P. AU - Viniotis, Y. AU - Vouk, M. T2 - Networking 2004: Networking technologies, services, and protocols: Performance of computer and communication networks, mobile and wireless commuication: Third International IFIP-TC6 Networking Conference, Athens, Greece, May 9-14, 2004 ; Proceedings AB - Several new protocols such as RBUDP, User-Level UDP, Tsunami, and SABUL, have been proposed as alternatives to TCP for high-speed data transfer. The purpose of this paper is to analyze experimentally the effects of SABUL congeston control algorithm on SABUL and performance metrics such as bandwidth utilization, self-fairness, and aggressiveness. Our results confirm some expected behavior of SABUL and reveal some less expected one. Our experiments also indicate that SABUL implementation and design can result in an even more erratic behavior and degraded performance under high-congestion conditions. CN - [Electronic Resource] PY - 2004/// DO - 10.1007/978-3-540-24693-0_131 VL - 3042 SP - 1433-1439 PB - Berlin; New York: Springer SN - 3540219595 ER - TY - JOUR TI - Envelope-function analysis of wurtzite InGaN/GaN quantum well light emitting diodes AU - Xiao, D. AU - Kim, K. W. AU - Zavada, J. M. T2 - Journal of Applied Physics AB - Fundamental electrical and optical properties of strained wurtzite InGaN/GaN-based quantum-well light-emitting diodes are calculated based on the Rashba–Sheka–Pikus Hamiltonian in the vicinity of the Γ point. It is found that the strain and the strain-induced piezoelectric field significantly alter the subband structure and determines the output intensity of the nitride quantum well light emitting diodes. For the case with high In composition (≳0.2), the calculation also supports the possibility of strain relaxation in the quantum well. Coupled with an optimized set of parameters, our theoretical model provides an excellent agreement with the available experimental data over a wide range of In composition (0–0.5). DA - 2004/7// PY - 2004/7// DO - 10.1063/1.1755435 VL - 96 IS - 1 SP - 723-728 J2 - Journal of Applied Physics LA - en OP - SN - 0021-8979 1089-7550 UR - http://dx.doi.org/10.1063/1.1755435 DB - Crossref ER - TY - JOUR TI - Chip-package co-implementation of a triple DES processor AU - Schaffer, T AU - Glaser, A AU - Franzon, PD T2 - IEEE TRANSACTIONS ON ADVANCED PACKAGING AB - This paper describes the design and implementation of a dedicated data encryption standard (DES) processor. The processor consists of three 0.6 /spl mu/m complementary metal oxide semiconductor (CMOS) integrated circuits (ICs) mounted on a single MCM-D thin-film substrate. Each chip can operate on an individual data stream, or the three can be cascaded to implement the so-called "triple-DES" (3DES) function for increased security. Measurements show 3DES operation at 110 MHz, which translates to a throughput of over 7 Gb/s, the highest reported 3DES throughput to date. System features which contribute to this throughput are the use of area-array (flip-chip) input/output (I/O) and global IC power/ground/clock distribution in the MCM package. In this case, package-level distribution reduced clock skew by 150 ps, and reduced the chip area required for power distribution by 20%. This paper also includes measurements of switching noise of the MCM's V/sub dd/ plane and how it correlates with a simple model of the system power distribution. DA - 2004/2// PY - 2004/2// DO - 10.1109/TADVP.2004.824944 VL - 27 IS - 1 SP - 194-202 SN - 1521-3323 KW - CMOS KW - DES processor KW - IC KW - I/O KW - MCM package ER - TY - JOUR TI - Characteristics of TaSixNy thin films as gate electrodes for dual gate Si-complementary metal-oxide-semiconductor devices AU - Suh, YS AU - Heuss, G AU - Misra, V T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B AB - Reactively sputtered TaSixNy films have been investigated as gate electrodes for dual gate Si-complementary metal-oxide-semiconductor devices. The as-deposited TaSixNy films were amorphous over a wide range of compositions. After annealing at 1000 °C, Ta30Si33N37 film became crystalline, however Ta26Si28N52 film remained amorphous. The x-ray photoelectron spectroscopy shows a significant increase of Si–N bonding in the TaSixNy films with increasing N content. The presence of Si–N bonds is attributed to cause the amorphous nature of the high N containing TaSixNy films. The work functions of TaSixNy films were extracted by capacitance–voltage analysis. The work function values for TaSixNy films with varying N contents range from 4.26 to 4.35 eV after forming gas annealing at 400 °C for 30 min, suggesting that TaSixNy films have work functions appropriate for n-type metal-oxide-semiconductor devices. However, it was observed, after 1000 °C anneals, that the work function of TaSixNy films increased to ∼4.8 eV. We believe that the mechanism that causes the work function to increase is the formation of a Ta-disilicide layer at the interface of the electrode and the dielectric. Current–voltage characteristics of the TaSixNy gates showed lower gate leakage compared to the TaSix gates, due to the retarding formation of an interface layer in the TaSixNy/SiO2/p-Si structures. DA - 2004/// PY - 2004/// DO - 10.1116/1.1640398 VL - 22 IS - 1 SP - 175-179 SN - 2166-2746 ER - TY - JOUR TI - A Ka-band power amplifier based on the traveling-wave power-dividing/combining slotted-waveguide circuit AU - Jiang, X AU - Ortiz, SC AU - Mortazawi, A T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - An eight-device Ka-band solid-state power amplifier has been designed and fabricated using a traveling-wave power-dividing/combining technique. The low-profile slotted-waveguide structure employed in this design provides not only a high power-combining efficiency over a wide bandwidth, but also efficient heat sinking for the active devices. The measured maximum small-signal gain of the eight-device power amplifier is 19.4 dB at 34 GHz with a 3-dB bandwidth of 3.2 GHz (f/sub L/=31.8 GHz, f/sub H/=35 GHz). The measured maximum output power at 1-dB compression (P/sub out/ at 1 dB) from the power amplifier is 33 dBm (/spl sim/2 W) at 32.2 GHz, with a power-combining efficiency of 80%. Furthermore, performance degradation of this power amplifier due to device failures has also been simulated and measured. DA - 2004/2// PY - 2004/2// DO - 10.1109/TMTT.2003.822026 VL - 52 IS - 2 SP - 633-639 SN - 1557-9670 KW - Ka-band KW - power combining KW - traveling wave KW - waveguide-to-microstrip transition ER - TY - JOUR TI - Multibit memory using self-assembly of mixed ferrocene/porphyrin monolayers on silicon AU - Li, QL AU - Mathur, G AU - Gowda, S AU - Surthi, S AU - Zhao, Q AU - Yu, LH AU - Lindsey, JS AU - Bocian, DF AU - Misra, V T2 - ADVANCED MATERIALS AB - An alternative strategy for achieving multi‐bit functionality , which uses mixed self‐assembled monolayers of a benzyl alcohol‐tethered ferrocene (Fc‐BzOH) and a benzyl alcohol‐tethered porphyrin (Por‐BzOH) on silicon surfaces to achieve a four‐state (2‐bit) memory element, is presented. The four states include the neutral state and three distinct cationic states obtained upon oxidation of Fc‐BzOH (monopositive) and Por‐BzOH (monopositive, dipositive) molecules. Conventional cyclic voltammetry, capacitance, and conductance methods have been used to characterize the mixed monolayer. DA - 2004/1/16/ PY - 2004/1/16/ DO - 10.1002/adma.200305680 VL - 16 IS - 2 SP - 133-+ SN - 1521-4095 ER - TY - JOUR TI - Impact of gate-to-source/drain overlap length on 80-nm CMOS circuit performance AU - Maitra, K AU - Bhat, N T2 - IEEE TRANSACTIONS ON ELECTRON DEVICES AB - In this paper, we perform rigorous mixed-mode simulations on two-stage inverter circuit and sample-hold circuits, representative of digital, and analog applications, respectively. The impact of gate-source/drain overlap length on circuit performance in an 80-nm CMOS circuit is evaluated by varying the overlap length between 0 to 20 nm, while keeping the subthreshold leakage current constraint at 1, 10, and 100 nA//spl mu/m. Process variations about the nominal overlap length have also been accounted for. The stage delay and switch error are used as the performance metrics. The lateral peak electric field is used as the metric for the hot carrier reliability. It is demonstrated that the overlap length should be made as small as possible, in spite of the increase in series resistance, in order to get the best circuit performance and reliability. DA - 2004/3// PY - 2004/3// DO - 10.1109/TED.2003.822347 VL - 51 IS - 3 SP - 409-414 SN - 0018-9383 KW - circuit KW - CMOS KW - gate KW - mixed mode KW - series resistance KW - source/drain overlap ER - TY - JOUR TI - Enhancing the durability of linen-like properties of low temperature mercerized cotton AU - Lee, M. H. AU - Park, H. S. AU - Yoon, K. J. AU - Hauser, P. J. T2 - Textile Research Journal AB - In order to develop durable linen-like cotton yam with low temperature mercerization, pretreatment methods ensuring efficient and uniform penetration of the low temperature alkali solution into cotton yarn are studied. Pretreatments consisting of an alkaline scouring at higher NaOH concentrations and of a cellulase treatment and subsequent alkaline scouring are evaluated for their efficiency in removing wax and enhancing absorptive properties. The cellulase treatment/alkaline scouring is more efficient at re moving wax than alkaline scouring at higher NaOH concentrations. The cellulase treat ment and subsequent alkaline scouring result in wax contents lower than 0.1%. The cellulase treatment appears to degrade the cellulose on the surface of the cotton fibers, making it more accessible to the scouring agent and making wax removal easier. Swelling and wetting times are compared to identify a pretreatment sufficient for developing linen-like cotton. In low temperature mercerization, the pretreatment consisting of cellu lase treatment and alkaline scouring yields a linen-like cotton yarn whose stiffness is durable to knitting, wet processing, and even ten laundering cycles. The durability appears to be sufficient for practical applications of the process for producing linen-like cotton. DA - 2004/// PY - 2004/// DO - 10.1177/004051750407400211 VL - 74 IS - 2 SP - 146-154 ER - TY - JOUR TI - Capacity planning of DiffServ networks with best-effort and Expedited Forwarding traffic AU - Wu, KH AU - Reeves, DS T2 - TELECOMMUNICATION SYSTEMS AB - For networks providing a specific level of service guarantees, capacity planning is an imperative part of network management. Accurate dimensioning is especially important in DiffServ networks, where no per-flow signaling or control exists. In this paper, we address the problem of capacity planning for DiffServ networks with only Expedited Forwarding (EF) and best effort (BE) traffic classes. The problem is formulated as an optimization problem, where the total link cost is minimized, subject to the performance constraints of both EF and BE classes. The edge to edge EF demand pairs and the BE demands on each link are given. The variables to be determined are the non-bifurcated routing of EF traffic, and the discrete link capacities. We show that Lagrangian relaxation and subgradient optimization methods can be used to effectively solve the problem. Computational results show that the solution quality is verifiably good while the running time remains reasonable on practical-sized networks. This represents the first work for capacity planning of multi-class IP networks with non-linear performance constraints and discrete link capacity constraints. DA - 2004/// PY - 2004/// DO - 10.1023/B:TELS.0000014781.92903.7f VL - 25 IS - 3-4 SP - 193-207 SN - 1572-9451 KW - DiffServ KW - capacity planning KW - Lagrangian relaxation ER - TY - JOUR TI - Buried bump and AC coupled interconnection technology AU - Mick, S AU - Luo, L AU - Wilson, J AU - Franzon, P T2 - IEEE TRANSACTIONS ON ADVANCED PACKAGING AB - A novel physical structure, buried solder bumps, is introduced that solves the compliance problems that exist in scaling present area array technologies to ever-higher densities. In this technique, buried bumps provide dc connections between integrated circuits and substrates and ac coupled interconnections provide paths for ac signals across the same interface. This approach requires co-design of packaging and circuits and meets the growing demands for both interconnect density and bandwidth. AC coupled interconnection arrays can be built with pitches for ac signals below 100 /spl mu/m and data rates of 6 Gb/s per I/O. This paper presents the physical and circuit aspects of this work as well as measured results from capacitively-coupled circuits fabricated in Taiwan semiconductor manufacturing Company (TSMC) 0.35-/spl mu/m technology. Simulated results from capacitively-coupled circuits in TSMC 0.18 /spl mu/m are also presented. DA - 2004/2// PY - 2004/2// DO - 10.1109/TADVP.2004.825482 VL - 27 IS - 1 SP - 121-125 SN - 1521-3323 KW - capacity-coupled circuits KW - coupled interconnections KW - integrated circuits KW - I/O KW - solder bumps ER - TY - JOUR TI - Breakdown and reliability of p-MOS devices with stacked RPECVD oxide/nitride gate dielectric under constant voltage stress AU - Lee, YM AU - Wu, YD AU - Lucovsky, G T2 - MICROELECTRONICS RELIABILITY AB - In this work, the effects of voltage and temperature on the TDDB characteristics of ∼2.0 nm stacked oxide/nitride (O/N) dielectric, prepared by remote plasma enhanced CVD (RPECVD), has been investigated. The breakdown characteristics and time-to-breakdown (tBD) are recorded from p+-poly/n-Si capacitors under constant voltage stress (CVS) at different temperatures. The tBD cumulative distributions exhibit a single Weibull slope β of ∼1.9 for different applied voltages. The charge-to-breakdown (QBD) is integrated from the gate current as a function of stress times, and can be used to extract the defect generation rate. The activation energy of 0.39 eV is determined from the Arrhenius law, and the average temperature acceleration factor is about 45 between 25 and 125 °C for a constant gate voltage. The extrapolation of the TDDB lifetime with low percentile failure rate of 0.01% provides a 10-year projection for a total gate area of 0.1 cm2 on a chip at 125 °C with the Poisson area-scaling law and a constant voltage acceleration factor of ∼14.83 V−1. It is projected that the maximum safe operating voltage is ∼1.9 V for 2.07 nm O/N gate dielectric. DA - 2004/2// PY - 2004/2// DO - 10.1016/j.microrel.2003.07.002 VL - 44 IS - 2 SP - 207-212 SN - 0026-2714 ER - TY - JOUR TI - Stability of Ru- and Ta-based metal gate electrodes in contact with dielectrics for Si-CMOS AU - Chen, ZQ AU - Misra, V AU - Haggerty, RP AU - Stemmer, S T2 - PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS AB - Abstract The Ru–Ta–Si–O, Ta–Si–N–O, and Ru–Ta–Zr–O phase diagrams are important for predicting reactions at interfaces between SiO 2 and ZrO 2 gate dielectrics and novel Ru and Ta‐based metal gate electrodes. Simplified quaternary phase diagrams of the Ru–Ta–Si–O, Ta–Si–N–O, and Ru–Ta–Zr–O systems at 900 °C were constructed from known and estimated Gibbs free energy data, respectively. Ru is predicted to be stable in contact with ZrO 2 and SiO 2 , whereas Ta is not stable in contact with SiO 2 at temperatures around 900 °C. Stoichiometric RuTa and TaN compounds were estimated to be stable in contact with both dielectrics at 900 °C. Experimental observations of gate electrode/dielectric interfaces are discussed. They are consistent with the thermodynamic predictions within the limitations of these phase diagrams. Metastable phases, often found in TaN x films, and diffusion of species from the vapor (e.g., oxygen), in particular along grain boundaries in columnar gate electrodes, may lead to reactions not predicted by the equilibrium phase diagrams. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) DA - 2004/8// PY - 2004/8// DO - 10.1002/pssb.200404933 VL - 241 IS - 10 SP - 2253-2267 SN - 1521-3951 ER - TY - JOUR TI - Performance analysis of buffered R-ALOHA systems using tagged user approach AU - Sheikh, AUH AU - Wan, T AU - Alakhdhar, SZ AU - Lambadaris, I AU - Devetsikiotis, M T2 - JOURNAL OF NETWORK AND COMPUTER APPLICATIONS AB - In this paper, R-ALOHA systems with propagation delay, finite buffer capacity and finite user population are analyzed using Tagged User Approach. The system throughput, message response time, message delay-time distribution and message blocking probability are obtained. It is assumed that each message consists of a random number of packets with a general distribution, and each user have a finite buffer capacity. To maintain the fairness to all users, it is assumed that each message in the buffer is transmitted independently that is, a user has to release the reserved slot after finishing the transmission of a message even if it has more messages waiting in the buffer. The analysis can be extended to R-ALOHA systems with infinite buffer capacity straightforwardly. The accuracy of the analysis is verified by simulations. DA - 2004/8// PY - 2004/8// DO - 10.1016/j.jnca.2003.11.002 VL - 27 IS - 3 SP - 131-150 SN - 1084-8045 ER - TY - JOUR TI - Smart nonlinear diffusion: A probabilistic approach AU - Bao, Y. F. AU - Krim, H. T2 - IEEE Transactions on Pattern Analysis and Machine Intelligence AB - In this paper, a stochastic interpretation of nonlinear diffusion equations used for image filtering is proposed. This is achieved by relating the problem of evolving/smoothing images to that of tracking the transition probability density functions of an underlying random process. We show that such an interpretation of, e.g., Perona-Malik equation, in turn allows additional insight and sufficient flexibility to further investigate some outstanding problems of nonlinear diffusion techniques. In particular, upon unraveling the limitations as well as the advantages of such an equation, we are able to propose a new approach which is demonstrated to improve performance over existing approaches and, more importantly, to lift the longstanding problem of a stopping criterion for a nonlinear evolution equation with no data term constraint. Substantiating examples in image enhancement and segmentation are provided. DA - 2004/// PY - 2004/// DO - 10.1109/TPAMI.2004.1261079 VL - 26 IS - 1 SP - 63-72 ER - TY - JOUR TI - The predictive user mobility profile framework for wireless multimedia networks AU - Akyildiz, IR AU - Wang, WY T2 - IEEE-ACM TRANSACTIONS ON NETWORKING AB - User mobility profile (UMP) is a combination of historic records and predictive patterns of mobile terminals, which serve as fundamental information for mobility management and enhancement of quality of service (QoS) in wireless multimedia networks. In this paper, a UMP framework is developed for estimating service patterns and tracking mobile users, including descriptions of location, mobility, and service requirements. For each mobile user, the service requirement is estimated using a mean-square error method. Moreover, a new mobility model is designed to characterize not only stochastic behaviors, but historical records and predictive future locations of mobile users as well. Therefore, our approach incorporates aggregate history and current system parameters to acquire UMP. In particular, an adaptive algorithm is designed to predict the future positions of mobile terminals in terms of location probabilities based on moving directions and residence time in a cell. Simulation results are shown to indicate that the proposed schemes are effective on mobility and resource management by evaluating blocking/dropping probabilities and location tracking costs in wireless networks. DA - 2004/12// PY - 2004/12// DO - 10.1109/tnet.2004.838604 VL - 12 IS - 6 SP - 1021-1035 SN - 1558-2566 KW - mobility and resource management KW - quality of service (QoS) KW - user mobility profile (UMP) KW - wireless network ER - TY - JOUR TI - Bit-interleaved space-time coded modulation with iterative decoding AU - Hong, ZH AU - Hughes, BL T2 - IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS AB - Bit-interleaved space-time coded modulation (BI-STC), which combines serial concatenation of bit-interleaved coded modulation (BICM) with space-time block codes, can effectively exploit the available diversity in space and time under various fading conditions. In this letter, we propose to use iterative decoding to further improve the performance of BI-STC by exploiting the concatenating structure of the codes. The decoding metric is therefore modified to fit for the iterative process, and the derived error bounds suggest that set-partition labeling instead of gray labeling should be used when considering iterative decoding. DA - 2004/11// PY - 2004/11// DO - 10.1109/twc.2004.837450 VL - 3 IS - 6 SP - 1912-1917 SN - 1558-2248 KW - bit-interleaved coded modulation KW - concatenated codes KW - iterative decoding KW - multiantenna communications KW - space-time coding KW - trellis codes ER - TY - JOUR TI - A modular 32-site wireless neural stimulation microsystem AU - Ghovanloo, M AU - Najafi, K T2 - IEEE JOURNAL OF SOLID-STATE CIRCUITS AB - This paper presents Interestim-2B, a modular 32-site wireless microstimulating ASIC for neural prosthesis applications, to alleviate disorders such as blindness, deafness, and severe epilepsy. Implanted just below the skull along with a high-density intracortical microelectrode array, the chip enables leadless operation of the resulting microsystem, accepting power and data through an inductive link from the outside world and inserting information into the nervous system in the form of stimulating currents. Each module contains eight current drivers, generating stimulus currents up to /spl plusmn/270 /spl mu/A with 5-b resolution, /spl sim/100M/spl Omega/ output impedance, and a dynamic range (headroom voltage) that extends within 150 mV of the 5 V supply rail, and 250 mV of the ground level. As many as 64 modules can be used in parallel, to drive multiprobe arrays of up to 2048 sites, with only a pair of connections to a common inductive-capacitive (LC) tank circuit, while receiving power (8.25 mW/module) and data (2.5 Mb/s) from a 5/10-MHz frequency shift keyed carrier. Every 4.6 mm /spl times/ 4.6 mm chip fabricated in a 1.5-/spl mu/m, 2M/2P standard CMOS process through MOSIS, houses two modules and generates up to 65 800 stimulus pulses/s. DA - 2004/12// PY - 2004/12// DO - 10.1109/JSSC.2004.837026 VL - 39 IS - 12 SP - 2457-2466 SN - 1558-173X KW - charge balancing KW - current source KW - frequency shift keying KW - implantable electronics KW - inductive coupling KW - microstimulator KW - modular architecture KW - neural prosthesis KW - voltage compliance KW - wireless ER - TY - JOUR TI - A hybrid current/voltage mode on-chip signaling scheme with adaptive bandwidth capability AU - Bashirullah, R AU - Liu, WT AU - Cavin, R AU - Edwards, D T2 - IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS AB - This brief describes an adaptive bandwidth bus architecture based on hybrid current/voltage mode repeaters for long global RC interconnect static busses that achieves high-data rates while minimizing the static power dissipation associated with current-mode (CM) signaling. An experimental adaptive bandwidth bus test chip fabricated in AMI 1.6-/spl mu/m Bulk CMOS indicates a reduction in power dissipation of approximately 62% over CM sensing and an increase in maximum data rate of 40% over voltage-mode signaling. DA - 2004/8// PY - 2004/8// DO - 10.1109/tvlsi.2004.831481 VL - 12 IS - 8 SP - 876-880 SN - 1557-9999 KW - adaptive KW - bus KW - current-mode (CM) KW - on-chip interconnects KW - repeater ER - TY - JOUR TI - Special section on distributed network-based control systems and applications - Editorial AU - Chow, MY T2 - IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS DA - 2004/12// PY - 2004/12// DO - 10.1109/TIE.2004.837890 VL - 51 IS - 6 SP - 1126-1126 SN - 0278-0046 ER - TY - JOUR TI - Reductions in interface defects, D-it, by post-oxidation plasma-assisted nitridation of GaN-SiO2 interfaces in MOS devices AU - Bae, C AU - Lucovsky, G T2 - APPLIED SURFACE SCIENCE AB - This paper applies remote plasma processing techniques, remote plasma assisted oxidation (nitridation) RPAO(N) and RP enhanced chemical vapor deposition (RPECVD), developed originally for fabrication of Si MOS devices with deposited SiO2, Si3N4 and Si oxynitride alloys to the formation of device-quality GaN MOS devices. Significant improvements in device performance for GaN–SiO2 interfaces are demonstrated by following an RPAO process step that forms the device interface with an interface nitridation RPAN step prior to the deposition of an SiO2 dielectric film by RPECVD. On-line Auger electron spectroscopy (AES) is used to monitor interface bonding for different ordering of RPAO and RPAN process steps. DA - 2004/7/15/ PY - 2004/7/15/ DO - 10.1016/j.apsusc.2004.05.077 VL - 234 IS - 1-4 SP - 475-479 SN - 1873-5584 KW - semiconductor-dielectric interfaces KW - remote plasma processing KW - interfacial defects ER - TY - JOUR TI - On the gain scheduling for networked PI controller over IP network AU - Tipsuwan, Y AU - Chow, MY T2 - IEEE-ASME TRANSACTIONS ON MECHATRONICS AB - The potential use of networks for real-time high-performance control and automation is enormous and appealing. Replacing a widely used proportional-integral (PI) controller by a new networked controller for networked control capability can be costly and time-consuming. This paper proposes a methodology based on gain scheduling with respect to real-time IP traffic conditions to enhance the existing PI controller so it can be used over IP networks with a general network protocol like Ethernet. This paper first describes the gain scheduling approach based on constant network delays using a rational function approach. The formulation is extended to random IP network round-trip time (RTT) delays by using the generalized exponential distribution model. Simulation results show that the PI controller with gain scheduling provides significantly better networked control system performance. DA - 2004/9// PY - 2004/9// DO - 10.1109/TMECH.2004.834645 VL - 9 IS - 3 SP - 491-498 SN - 1941-014X KW - adaptive control KW - control systems KW - dc motors KW - distributed control KW - Internet KW - networks KW - real-time system ER - TY - JOUR TI - Mini-special issue on terahertz electronics - Editorial AU - Steer, M T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES DA - 2004/10// PY - 2004/10// DO - 10.1109/TMTT.2004.835907 VL - 52 IS - 10 SP - 2337-2337 SN - 0018-9480 ER - TY - JOUR TI - Mini-Special, Issue on the 2004 IEEE Mtt-S International Microwave Symposium - Early Papers AU - Steer, M T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES DA - 2004/11// PY - 2004/11// DO - 10.1109/TMTT.2004.837338 VL - 52 IS - 11 SP - 2457-2457 SN - 0018-9480 ER - TY - JOUR TI - Investigation of stress behaviors and mechanism of void formation in sputtered TiSix films AU - Suh, YS AU - Park, DG AU - Jang, SA T2 - THIN SOLID FILMS AB - We have investigated the stress behaviors and a mechanism of void formation in TiSix films during annealing. TiSix thin films were prepared by DC magnetron sputtering using a TiSi2.1 target in the substrate temperature range of 200–500 °C. The as-deposited TiSix films at low substrate temperature (<300 °C) have an amorphous structure with low stress of ∼1×108 dynes/cm2. When the substrate temperature increases to 500 °C, the as-deposited TiSix film has a mixture of C49 and C54 TiSi2 phase with stress of ∼8×109 dynes/cm2. No void was observed in the as-deposited TiSix film. Amorphous TiSix film transforms to C54 TiSi2 phase with a random orientation of (311) and (040) after annealing at 750 °C. The C49 and C54 TiSi2 mixture phase transforms to (040) preferred C54 TiSi2 phase after annealing over 650 °C. By increasing substrate temperature, the transformation temperature for C54 TiSi2 can be reduced, resulting in relieved stress of TiSi2 film. The easy nucleation of the C54 phase was attributed to an avoidance of amorphous TiSix phase. We found that amorphous TiSix→C54 TiSi2 transformation caused higher tensile stress of 2×1010 dynes/cm2, resulting in more voids in the films, than C49→C54 transformation. It was observed that void formation was increased with thermal treatment. The high tensile stress caused by volume decreases in the silicide must be relieved to retard voids and cracks during C54 TiSi2 formation. DA - 2004/3/1/ PY - 2004/3/1/ DO - 10.1016/j.tsf.2003.11.165 VL - 450 IS - 2 SP - 341-345 SN - 0040-6090 KW - TiSix films KW - substrate temperature KW - stress behaviors ER - TY - JOUR TI - Fully integrated wideband high-current rectifiers for inductively powered devices AU - Ghovanloo, M AU - Najafi, K T2 - IEEE JOURNAL OF SOLID-STATE CIRCUITS AB - This paper describes the design and implementation of fully integrated rectifiers in BiCMOS and standard CMOS technologies for rectifying an externally generated RF carrier signal in inductively powered wireless devices, such as biomedical implants, radio-frequency identification (RFID) tags, and smartcards to generate an on-chip dc supply. Various full-wave rectifier topologies and low-power circuit design techniques are employed to decrease substrate leakage current and parasitic components, reduce the possibility of latch-up, and improve power transmission efficiency and high-frequency performance of the rectifier block. These circuits are used in wireless neural stimulating microsystems, fabricated in two processes: the University of Michigan's 3-/spl mu/m 1M/2P N-epi BiCMOS, and the AMI 1.5-/spl mu/m 2M/2P N-well standard CMOS. The rectifier areas are 0.12-0.48 mm/sup 2/ in the above processes and they are capable of delivering >25mW from a receiver coil to the implant circuitry. The performance of these integrated rectifiers has been tested and compared, using carrier signals in 0.1-10-MHz range. DA - 2004/11// PY - 2004/11// DO - 10.1109/JSSC.2004.835822 VL - 39 IS - 11 SP - 1976-1984 SN - 1558-173X KW - BiCMOS KW - biomedical implants KW - CMOS KW - full-wave KW - inductive coupling KW - latch-up KW - power supply KW - rectifier KW - RFID KW - substrate leakage KW - telemetry KW - wireless ER - TY - JOUR TI - Electrical characterization of B-10 doped diamond irradiated with low thermal neutron fluence AU - Reed, ML AU - Reed, MJ AU - Jagannadham, K AU - Verghese, K AU - Bedair, SM AU - El-Masry, N AU - Butler, JE T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - A sample of B10 isotope doped diamond was neutron irradiated to a thermal fluence of 1.3×1019 neutron cm−2. The diamond sample was cooled continuously during irradiation in a nuclear reactor. Li7 is formed by nuclear transmutation reaction from B10. Characterization for electrical conductance in the temperature range of 160 K&lt;T&lt;600 K was performed on an unirradiated B10 doped sample and the B10 doped and irradiated sample. The unirradiated diamond sample showed p-type conductance at higher temperature (T&gt;200 K) and p-type surface conductance at lower temperature (T&lt;200 K). The irradiated sample showed decreasing conductance below 230 K and increasing conductance above 230 K with increasing temperature. Furthermore, the conductance showed a decrease above 400 K followed by an increase above 500 K. The observed behavior below 400 K with increase in temperature is interpreted in terms of compensation of surface p-type carriers by n-type bulk carriers generated from Li7 that is formed by nuclear transmutation reaction from B10 atoms. Also, compensation of n-type carriers from Li7 by p-type carriers from B10 is used to interpret the conductance above 400 K. A low concentration of radiation induced defects, absence of defect complexes, and the low activation energy of n-type Li7 are thought responsible for the observed variation of conductance in the irradiated diamond. The present results illustrate that neutron transmutation from B10 doped diamond is a useful method to achieve n-type conductivity in diamond. DA - 2004/// PY - 2004/// DO - 10.1116/1.1763910 VL - 22 IS - 4 SP - 1191-1194 SN - 1520-8559 ER - TY - JOUR TI - Design and performance of a new digital phase shifter at X-band AU - Jin, Z AU - Ortiz, S AU - Mortazawi, A T2 - IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS AB - A new digital phase shifter design at X-band is presented. The phase shifter operates based on converting a microstrip line to a rectangular waveguide and thus achieving the phase shift by changing the wave propagation constant through the medium. As a proof of principle, a 3-b phase shifter has been designed and constructed using PIN diode switches. An average insertion loss of 1.95 dB and phase shift error of less than 4/spl deg/ at 10.6 GHz are achieved. DA - 2004/9// PY - 2004/9// DO - 10.1109/LMWC.2004.832049 VL - 14 IS - 9 SP - 428-430 SN - 1531-1309 KW - microstrip line KW - phase shifter KW - PIN diode switches KW - rectangular waveguide KW - wave propagation mode ER - TY - JOUR TI - Comparing observers AU - Kuehni, RG AU - Ramanath, R T2 - COLOR RESEARCH AND APPLICATION AB - Abstract Color‐matchingfunctions may be considered dimension reduction functions that project a spectral reflectance function into the desired space of colors. Using a gray metameric pair with maximal spectral difference we compare the abilities of various human and other observers with regard to the transition wavelengths for that metameric pair. Transition wavelengths are shown to be a convenient tool for comparing and classifying observers regardless of the number of dimension reduction functions. Four human observers were identified as differing in a comparable manner from the CIE 2° standard observer. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 183–186, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20004 DA - 2004/6// PY - 2004/6// DO - 10.1002/col.20004 VL - 29 IS - 3 SP - 183-186 SN - 1520-6378 KW - color perception KW - color-matching functions KW - metamerism ER - TY - CHAP TI - A Local search sat solver using an effective switching strategy and an efficient unit propagation AU - Li, X. Y. AU - Stallmann, M. F. AU - Brglez, F. T2 - Theory and applications of satisfiability testing: 6th International Conference, SAT 2003, Santa Margherita Ligure, Italy, May 5-8, 2003, Selected revised papers CN - QA9.3 .S365 2003 PY - 2004/// VL - 2919 SP - 53-68 PB - Berlin; New York: Springer SN - 3540208518 ER - TY - JOUR TI - Stability of advanced gate stack devices AU - Kim, I AU - Han, SK AU - Osburn, CM T2 - JOURNAL OF THE ELECTROCHEMICAL SOCIETY AB - The stability of poly-Si gated (∼1.2 nm equivalent oxide thickness, EOT) and (∼3.1 nm EOT) n-channel metal oxide semiconductor field effect transistor devices were assessed after constant current stressing of the gate. The changes in threshold voltage and transconductance were measured as a function of stress time and stress current over the range of to C of injected charge per square centimeter. With forming gas annealed positive shifts in the threshold voltage exhibited a power- law dependence. Under high stressing conditions, a power-law dependence of degradation of threshold voltage on the injected charge was observed. Stressing at high current was seen to generate traps. Stressing at low current revealed a saturation of the threshold voltage after modest stressing times. Stressing on deuterium annealed sample showed less and shift (under high injection conditions), which is attributed to the effectiveness of heavier in preventing trap generation under high stressing conditions. With stressed at similar electric fields, the threshold voltage shifted negatively and the transconductance increased. © 2004 The Electrochemical Society. All rights reserved. DA - 2004/2// PY - 2004/2// DO - 10.1149/1.1636180 VL - 151 IS - 2 SP - F22-F28 SN - 1945-7111 ER -