TY - JOUR TI - Optical cavity effects in InGaN/GaN quantum-well-heterostructure flip-chip light-emitting diodes AU - Shen, Y. C. AU - Wierer, J. J. AU - Krames, M. R. AU - Ludowise, M. J. AU - Misra, M. S. AU - Ahmed, F. AU - Kim, A. Y. AU - Mueller, G. O. AU - Bhat, J. C. AU - Stockman, S. A. AU - Martin, P. S. T2 - Applied Physics Letters AB - Optical cavity effects have a significant influence on the extraction efficiency of InGaN/GaN quantum-well-heterostructure flip-chip light-emitting diodes (FCLEDs). Light emitted from the quantum well (QW) self-interferes due to reflection from a closely placed reflective metallic mirror. The interference patterns couple into the escape cone for light extraction from the FCLED. This effect causes significant changes in the extraction efficiency as the distance between the QW and the metallic mirror varies. In addition, the radiative lifetime of the QW also changes as a function of the distance between the QW and the mirror surface. Experimental results from packaged FCLEDs, supported by optical modeling, show that a QW placed at an optimum distance from the mirror provides a ∼2.3× increase in total light output as compared to a QW placed at a neighboring position corresponding to a minimum in overall light extraction. DA - 2003/// PY - 2003/// DO - 10.1063/1.1566098 VL - 82 IS - 14 SP - 2221-2223 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000182018800009&KeyUID=WOS:000182018800009 ER - TY - JOUR TI - Effect of anticholinergic medications on taste, smell, and other senses as well as cognition in the elderly AU - Schiffman, S.S. AU - Kondor, A.M. AU - Zervakis, J. T2 - Chemical Senses DA - 2003/// PY - 2003/// VL - 28 SP - A40 ER - TY - CONF TI - An integrated study of the emissions of ammonia, odor and odorants, and pathogens and related contaminants from potential environmentally superior technologies for swine facilities AU - V.P., Aneja AU - D. S., Kim AU - Schiffman, S. AU - Graham, B. T2 - Program OPEN (Odor, Pathogens, and Emissions of Nitrogen). Gaseous and odour emissions from animal production facilities C2 - 2003/6/1/ C3 - Proceedings of Gaseous and odour emissions from animal production facilities CY - Horsens, Denmark DA - 2003/6/1/ PY - 2003/6/1/ ER - TY - CONF TI - Predicting odor dispersion at five swine facilities Using a Eulerian Lagrangian model AU - Schiffman, S.S. AU - Graham, B.G. AU - McLaughlin, B. AU - Fitzpatrick, D. AU - Katul, G.G. AU - Nagle, H.T. AU - Williams, C.M. T2 - North Carolina animal waste management workshop C2 - 2003/// C3 - Proceedings of the North Carolina animal waste management workshop, Research Triangle Park, Oct 17-17 CY - Research Triangle Park, NC DA - 2003/// PY - 2003/10/17/ PB - North Carolina State University College of Agriculture and Life Sciences Waste Management Programs ER - TY - CONF TI - Power Packaging Techniques with Emphasis on High Current Applications AU - Hopkins, Douglas C. T2 - 18th Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC) C2 - 2003/2/9/ C3 - 18th Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC) CY - Miami Beach, FL. DA - 2003/2/9/ PY - 2003/2/9/ ER - TY - JOUR TI - Introduction: health and ecological linkages AU - Schiffman, Susan S. T2 - Environment International DA - 2003/6// PY - 2003/6// DO - 10.1016/s0160-4120(02)00168-x VL - 29 IS - 2-3 SP - 351 J2 - Environment International LA - en OP - SN - 0160-4120 UR - http://dx.doi.org/10.1016/s0160-4120(02)00168-x DB - Crossref ER - TY - ER - TY - JOUR TI - Effect of Repeated Presentation on Sweetness Intensity of Binary and Ternary Mixtures of Sweeteners AU - Schiffman, S. S. T2 - Chemical Senses AB - The purpose of the present study was to determine the effect of repeated presentation of the same sweet stimulus on sweetness intensity ratings. The sweet stimuli tested in this study were binary and ternary blends of 14 sweeteners that varied widely in chemical structure. A trained panel evaluated the sweetness intensity over four sips of a given mixture presented at 30 s intervals. The individual components in the binary sweetener combinations were intensity-anchored with 5% sucrose, while the individual sweeteners in the ternary mixtures were intensity-anchored with 3% sucrose (according to formulae developed previously). Each self-mixture was also evaluated (e.g. acesulfame-K-acesulfame-K). The main finding of this study was that mixtures consisting of two or three different sweeteners exhibited less reduction in sweetness intensity over four repeated sips than a single sweetener at an equivalent sweetness level. Furthermore, ternary combinations tended to be slightly more effective than binary combinations at lessening the effect of repeated exposure to a given sweet stimulus. These findings suggest that the decline in sweetness intensity experienced over repeated exposure to a sweet stimulus could be reduced by the blending of sweeteners. DA - 2003/3/1/ PY - 2003/3/1/ DO - 10.1093/chemse/28.3.219 VL - 28 IS - 3 SP - 219-229 OP - SN - 1464-3553 UR - http://dx.doi.org/10.1093/chemse/28.3.219 DB - Crossref ER - TY - CONF TI - On the optimum secrecy capacity of multiple relay networks AU - Koli, M.N.Y. AU - Sarkar, M.Z.I. AU - Tazrin, S. AU - Pervej, M.F. AB - We consider a confidential communication system in which a source sends a confidential information to the destination in the presence of an eavesdropper. Multiple relays are used to provide cooperative diversity to the destination. The destination and the eavesdropper are equipped with multiple antennas while each relay and source are equipped with single antenna. We are interested to protect the transmitted information from eavesdropping and to find the effect of receive diversity on the secrecy capacity of the proposed model. We consider the maximal ratio combining (MRC) technique at the destination and derive the expression of combiner output signal-to-noise ratio (SNR) using optimum weighting vector so that the eavesdropper is unable to decode a single bit from the original massage. Finally, we derive the expression of optimum secrecy capacity in terms of the number of relays and the number of antennas at the destination. Our results show that the optimization of weighting vector at the receiver enhances secrecy capacity of a wiretap channel. C2 - 2003/// C3 - 2014 17th International Conference on Computer and Information Technology, ICCIT 2014 DA - 2003/// DO - 10.1109/ICCITechn.2014.7073091 SP - 514-517 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84949924107&partnerID=MN8TOARS ER - TY - CONF TI - Impact of underwater bandwidth on cross-correlation based node estimation technique AU - Bain, S.K. AU - Chowdhury, S.A.H. AU - Asif, A.H.M. AU - Anower, M.S. AU - Pervej, M.F. AU - Haque, S.S. AB - Bandwidth is the most monumental topic both for the terrestrial and underwater communications. For proper network operation the estimation of number of signal sources (N) is very important. Most of the protocol based techniques are failed to give the desired results of node estimation due to underwater properties (long propagation delay, high absorptions and dispersion). Node estimation technique using cross-correlation is not based on protocol, where infinite band Gaussian signals are used. But the underwater bandwidth is finite (1-15 kHz). This limited bandwidth can encumber the signal bandwidth which might invade the estimation process. In this paper, the number of estimated nodes is being obtained considering the effect of underwater bandwidth using three sensors. C2 - 2003/// C3 - 2014 17th International Conference on Computer and Information Technology, ICCIT 2014 DA - 2003/// DO - 10.1109/ICCITechn.2014.7073137 SP - 494-497 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84949924255&partnerID=MN8TOARS ER - TY - CONF TI - Impact analysis of input and output block size of DCT-SCFDMA system AU - Pervej, M.F. AU - Sarkar, M.Z.I. AU - Roy, T.K. AU - Koli, M.N.Y. AB - This paper aims to analyze the bit error rate (BER) and peak to average power ratio (PAPR) for discrete cosine transform (DCT) based single carrier frequency division multiple access (SCFDMA) system. Note that BER and PAPR are the major concerns for any wireless communication and for having lower PAPR till now discrete Fourier transform (DFT) based SCFDMA is implemented for the up-link communication for long term evolution (LTE). This paper focuses to analyze the effect of the input and output block size of DCT based SCFDMA system which is a supplementary of the DFT-SCFDMA system. Using the conventional raised cosine (RC) and square root raised cosine (RRC) pulse shaping filters with different sub-carrier mapping schemes (e.g. interleaved frequency division multiple access (IFDMA), localized frequency division multiple access (LFDMA) and distributed frequency division multiple access (DFDMA)) the paper analyze the PAPR for the DCT based SCFDMA system. The suitable block size of DCT-SCFDMA is very important to improve the BER and PAPR performances of the system because if the block sizes vary then the PAPR also changes. Therefore, this paper also analyzes the impact of the input and output block size of the system. Finally, the numerical evaluation is done using the pulse shaping filter for different sub-carrier mapping schemes based on the different block sizes. From the numerical analysis and evaluation this paper shows the way to chose the input and output block size to have a significantly low PAPR and BER. C2 - 2003/// C3 - 2014 17th International Conference on Computer and Information Technology, ICCIT 2014 DA - 2003/// DO - 10.1109/ICCITechn.2014.7073068 SP - 440-445 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84949924614&partnerID=MN8TOARS ER - TY - CONF TI - Effect of node number in range based node localization technique for underwater communications network AU - Hasan, M.M. AU - Paul, A. AU - Haque, S.S. AU - Chowdhury, S.A.H. AU - Pervej, M.F. AU - Hossen, M.A. AB - In underwater network, it is very important to know the location of unmanned underwater vehicle (UUV). The unknown position of UUV considered as an unknown node that can be determined from the known node locations through underwater acoustic network. The known node locations considered here as fixed positioned node. The range data is measured between unknown node and known nodes. By exploiting these measured range data and combination among fixed positioned nodes on this network, it is possible to perform underwater positioning of unknown node (UUV), similar to that of the satellite-based GPS program. The aim of this paper is to determine the position of UUV in an underwater acoustic network using combination method with different number of nodes, whose locations are known, to analyze the effect of node number in position estimation. C2 - 2003/// C3 - 2014 17th International Conference on Computer and Information Technology, ICCIT 2014 DA - 2003/// DO - 10.1109/ICCITechn.2014.7073099 SP - 413-417 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84949924869&partnerID=MN8TOARS ER - TY - CONF TI - Analysis of PAPR reduction of DFT-SCFDMA system using different sub-carrier mapping schemes AU - Pervej, M.F. AU - Sarkar, M.Z.I. AU - Roy, T.K. AU - Hasan, M.M. AU - Rahman, M.M. AU - Bain, S.K. AB - This paper is concerned with the reduction of peak to average power ratio (PAPR) of 3rd generation partnership project (3GPP) LTE standard using the single carrier-frequency division multiple access (SCFDMA) for mobile uplink transmission. The PAPR reduction is done based on the discrete Fourier transform (DFT) spreading technique which is well known as DFT - SCFDMA and in case of LTE which can reduce the PAPR of OFDM signal to a level of single carrier transmission. Note that the needed power of the signals for uplink transmission of LTE is varied depending on the different sub-carrier mapping and modulation techniques. This paper discusses different sub-carrier mapping techniques such as-localized FDMA (IFDMA), distributed FDMA (DFDMA) and interleaved FDMA (IFDMA). To show the effectiveness of DFT-SCFDMA in the reduction of PAPR with different sub-carrier mapping and modulation techniques the results are compared with the conventional OFDMA system. This paper also shows the comparative results of different sub-carrier mapping techniques in terms of symbol error rate (SER). The comparative results show that the DFT-SCFDMA greatly enhances the PAPR reduction for LTE uplink transmission over the conventional OFDMA. C2 - 2003/// C3 - 2014 17th International Conference on Computer and Information Technology, ICCIT 2014 DA - 2003/// DO - 10.1109/ICCITechn.2014.7073067 SP - 435-439 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84949924382&partnerID=MN8TOARS ER - TY - CHAP TI - Real-Time System-on-a-Chip Emulation AU - Kuusilinna, K. AU - Chang, C. AU - Bluethgen, H.M. AU - Davis, W.R. AU - Richards, B. AU - Nikolić, B. AU - Brodersen, R.W. T2 - Winning the SoC Revolution A2 - Martin, Grant A2 - Chang, Henry PY - 2003/5// DO - 10.1007/978-1-4615-0369-9_10 SP - 229-253 PB - Springer ER - TY - CONF TI - Getting High-Performance Silicon from System-Level Design AU - Davis, W.R. T2 - IEEE Computer Society Annual Symposium on VLSI AB - System-level design techniques promise a way to lessen the productivity gap between fabrication and design. Unfortunately, these techniques have been slow to catch on, in part because they do little to help designers optimize hardware. This paper presents a brief summary of three system-level design techniques. Platform-based design, SystemC, and Chip-in-a-day, in order to propose that more system-level abstraction of physical performance is needed to make these techniques more useful. An analysis of design-productivity for three chips designed with the Chip-in-a-Day flow is also presented. C2 - 2003/2// C3 - IEEE Computer Society Annual Symposium on VLSI, 2003. Proceedings. CY - Tampa, FL DA - 2003/2// PY - 2003/2/20/ DO - 10.1109/ISVLSI.2003.1183482 SP - 238–243 ER - TY - JOUR TI - 500 Mb/s Soft Output Viterbi Decoder AU - Yeo, E. AU - Augsburger, S. AU - Davis, W.R. AU - Nikolić, B. T2 - IEEE Journal of Solid State Circuits AB - Two eight-state 7-bit soft-output Viterbi decoders matched to an EPR4 channel and a rate-8/9 convolutional code are implemented in a 0.18-μm CMOS technology. The throughput of the decoders is increased through architectural transformation of the add-compare-select recursion, with a small area overhead. The survivor-path decoding logic of a conventional Viterbi decoder register exchange is adapted to detect the two most likely paths. The 4-mm 2 chip has been verified to decode at 500 Mb/s with 1.8-V supply. These decoders can be used as constituent decoders for Turbo codes in high-performance applications requiring information rates that are very close to the Shannon limit. DA - 2003/7// PY - 2003/7// DO - 10.1109/JSSC.2003.813250 VL - 38 IS - 7 SP - 1234–1241 KW - iterative decoders KW - turbo codes KW - Viterbi decoder KW - VLSI ER - TY - CONF TI - Automated Design Flows for High-Performance Systems AU - Davis, W.R. T2 - OpenAccess Conference C2 - 2003/2/11/ CY - San Jose, CA DA - 2003/2/11/ PY - 2003/2/11/ ER - TY - SOUND TI - System-Level Design: Past, Present, and Future AU - Davis, W.R. DA - 2003/2// PY - 2003/2// 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. 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 - 2003/// C3 - Proceedings of the IEEE 2003 International Interconnect Technology Conference, IITC 2003 DA - 2003/// DO - 10.1109/IITC.2003.1219727 SP - 111-113 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84944035888&partnerID=MN8TOARS ER - TY - CONF TI - 60GHz transceiver circuits in SiGe bipolar technology AU - Reynolds, S. AU - Floyd, B. AU - Pfeiffer, U. AU - Zwick, T. C2 - 2003/// C3 - Digest of Technical Papers - IEEE International Solid-State Circuits Conference DA - 2003/// VL - 47 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-2442715211&partnerID=MN8TOARS ER - TY - JOUR TI - Measuring Joint Reliability: Applying the Moire Interferometry Technique AU - Ye, H. AU - Basaran, C. AU - Hopkins, D.C. T2 - Advanced Microelectronics Magazine DA - 2003/5// PY - 2003/5// VL - 12 IS - 5 SP - 17–20 ER - TY - JOUR TI - Flip Chip and BGA Solder Joint Reliability AU - Ye, Hua AU - Basaran, Cemal AU - Hopkins, Douglas C. AU - Liu, Heng AU - Cartright, Alexander T2 - Advanced Packaging DA - 2003/5// PY - 2003/5// VL - 12 IS - 5 SP - 17–19 ER - TY - JOUR TI - Measurement of Electrical Current Density Effects in Solder Joints AU - Ye, Hua AU - Hopkins, Douglas C. AU - Basaran, Cemal T2 - Advancing Microelectronics DA - 2003/9// PY - 2003/9// VL - 30 IS - 5 ER - TY - CONF TI - Partitioning digitally programmable power-control for applications to ballasts AU - Hopkins, D.C. AU - Moronski, J. T2 - APEC 2002 - Applied Power Electronics Conference and Exposition AB - The move to full digital control of power electronic circuits has been mixed. This paper describes the procession of technology to embed digital power control in power supply circuits, with particular attention to dimmable fluorescent lighting ballasts. Partitioning of power circuits shows a near optimum match with the evolving system on chip (SoC) approach taken for microcontrollers to provide an integrated digital power control. A performance description of several approaches is given with performance bounds. C2 - 2003/6/25/ C3 - APEC. Seventeenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.02CH37335) CY - Dallas, TX DA - 2003/6/25/ PY - 2002/3/10/ DO - 10.1109/apec.2002.989356 PB - IEEE SN - 0780374045 UR - http://dx.doi.org/10.1109/apec.2002.989356 ER - TY - CONF TI - Reliability of solder joints under electrical stressing - strain evolution of solder joints AU - Ye, Hua AU - Basaran, C. AU - Hopkins, D. AU - Cartwright, A. T2 - ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems AB - Damage mechanics of solder interconnects under electrical stressing is an important reliability issue for next generation power electronic packaging as well as for future IC packaging. The high electrical stressing in solder joints leads to electromigration and thus could not be ignored. In this paper, the state-of-the-art research on electromigration in solder joints is reviewed. An experimental electromigration study on solder joints is conducted and results are reported in this paper. The strain field in the solder joints under electrical stressing is measured with Moire Interferometry technique. C2 - 2003/6/25/ C3 - ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258) CY - San Diego, CA DA - 2003/6/25/ PY - 2002/5/30/ DO - 10.1109/itherm.2002.1012558 PB - IEEE SN - 0780371526 UR - http://dx.doi.org/10.1109/itherm.2002.1012558 KW - electromigration KW - Moire Interferometry KW - electronic packaging KW - power electronics ER - TY - JOUR TI - Mechanical degradation of microelectronics solder joints under current stressing AU - Ye, Hua AU - Basaran, Cemal AU - Hopkins, Douglas C. T2 - International Journal of Solids and Structures AB - Understanding the mechanical degradation of microelectronic solder joints under high electric current stressing is an important step to develop a damage mechanics model in order to predict the reliability of a solder joint under such loading. In this paper, the experiment results for flip chip solder joints under high current stressing are reported. Nano-indentation tests suggest that mechanical property, e.g. Young’s modulus, degrades in the localized area where void nucleates during current stressing. The experiments also show that thermomigration due to the thermal gradient within solder joint caused by joule heating is significant during current stressing. A three-dimensional coupled thermal electrical finite element analysis shows the existence of a significant thermal gradient in solder joint during current stressing. DA - 2003/12// PY - 2003/12// DO - 10.1016/j.ijsolstr.2003.08.019 VL - 40 IS - 26 SP - 7269-7284 J2 - International Journal of Solids and Structures LA - en OP - SN - 0020-7683 UR - http://dx.doi.org/10.1016/j.ijsolstr.2003.08.019 DB - Crossref ER - TY - JOUR TI - Thermomigration in Pb–Sn solder joints under joule heating during electric current stressing AU - Ye, Hua AU - Basaran, Cemal AU - Hopkins, Douglas T2 - Applied Physics Letters AB - Electromigration of solder joint under high dc current density is known as a reliability concern for the future high-density flip chip packaging and power packaging. Biased mass diffusion within solder joint from cathode to anode under high dc current density is observed in these experiments. In this letter, the experiments on flip chip solder joints under dc current stressing are conducted and thermomigration due to the thermal gradient in the solder joint caused by joule heating is reported. A three-dimensional coupled electric thermal finite-element (FE) simulation of a realistic flip chip module shows the existence of thermal gradient in the solder joint which is high enough to trigger thermomigration. DA - 2003/2/17/ PY - 2003/2/17/ DO - 10.1063/1.1554775 VL - 82 IS - 7 SP - 1045-1047 J2 - Appl. Phys. Lett. LA - en OP - SN - 0003-6951 1077-3118 UR - http://dx.doi.org/10.1063/1.1554775 DB - Crossref ER - TY - JOUR TI - Numerical simulation of stress evolution during electromigration in IC interconnect lines AU - Ye, Hua AU - Basaran, C. AU - Hopkins, D.C. T2 - IEEE Transactions on Components and Packaging Technologies AB - A finite element simulation of stress evolution in thin metal film during electromigration is reported in this paper. The electromigration process is modeled by a coupled diffusion- mechanical partial differential equations (PDEs). The PDEs are implemented with a plane strain formulation and numerically solved with the finite element (FE) method. The evolutions of hydrostatic stress, each component of the deviatoric stress tensor, and Von Mises' stress were simulated for several cases with different line lengths and current densities. Two types of displacement boundary conditions are considered. The simulation results are compared with Korhonen's analytical model and Black and Blech's experimentalesults. DA - 2003/9// PY - 2003/9// DO - 10.1109/tcapt.2003.817877 VL - 26 IS - 3 SP - 673-681 J2 - IEEE Trans. Comp. Packag. Technol. LA - en OP - SN - 1521-3331 UR - http://dx.doi.org/10.1109/tcapt.2003.817877 DB - Crossref KW - deviatoric stress tensor KW - electromigration KW - FE KW - hydrostatic stress KW - PDEs KW - stress evolution ER - TY - JOUR TI - Damage mechanics of microelectronics solder joints under high current densities AU - Ye, Hua AU - Basaran, Cemal AU - Hopkins, Douglas C. T2 - International Journal of Solids and Structures AB - The electromigration damage in flip chip solder joints of eutectic SnPb was studied under current stressing at room temperature with a current density of 1.3 × 104 A/cm2. The height of the solder joints was 100 μm. The mass accumulation near anode side and void nucleation near cathode were observed during current stressing. The nano-indentation test was performed on solder joints for electromigration test. Surface marker movement 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 at room temperature. The effective charge number can be extracted with the solder diffusivity at room temperature known. Pb phase coarsening was observed during current stressing. DA - 2003/7// PY - 2003/7// DO - 10.1016/s0020-7683(03)00175-6 VL - 40 IS - 15 SP - 4021-4032 J2 - International Journal of Solids and Structures LA - en OP - SN - 0020-7683 UR - http://dx.doi.org/10.1016/s0020-7683(03)00175-6 DB - Crossref KW - solder joint KW - reliability KW - electromigration KW - nano-indentation KW - coarsening ER - TY - JOUR TI - Measurement of high electrical current density effects in solder joints AU - Ye, Hua AU - Hopkins, Douglas C. AU - Basaran, Cemal T2 - Microelectronics Reliability AB - Measuring mechanical implications of high current densities in microelectronic packaging interconnects has always been a challenging goal. Due to small interconnect size this task has typically been accomplished by measuring the change in electrical resistance of the joint. This measurement parameter is global and does not give local mechanical state information. Also, understanding strain evolution in the solder over time is an important step toward developing a damage mechanics model. The real-time, full-field, strain displacement in a eutectic Sn/Pb solder joint during electrical current stressing was measured with Moiré interferometry (Post et al., High sensitivity Moire, Springer, New York, 1994) under in situ conditions. A finite element model simulation for thermal stressing was performed and compared with measured strain. The initial results show that the measured strain was largely due to thermal stressing versus the current density of 1.8 × 102 A/cm2. A second Moiré interferometry experiment with thermal control distinguishes deformation of solder joint due to pure current stressing above 5000 A/cm2. DA - 2003/12// PY - 2003/12// DO - 10.1016/s0026-2714(03)00131-8 VL - 43 IS - 12 SP - 2021-2029 J2 - Microelectronics Reliability LA - en OP - SN - 0026-2714 UR - http://dx.doi.org/10.1016/s0026-2714(03)00131-8 DB - Crossref ER - TY - THES TI - A novel compiler framework for a chip-multiprocessor architecture with thread-level speculation AU - Tuck, James Murray DA - 2003/// PY - 2003/// PB - University of Illinois at Urbana-Champaign ER - TY - CONF TI - Web-based Asset Management Tools AU - Hasselstrom, Jorgen AU - Lubkeman, David AU - Li, Fangxing AU - Wang, John AU - Liao, Yuan T2 - DistribuTech Conference C2 - 2003/2// C3 - Proceedings of DistribuTech Conference CY - Las Vegas, NV DA - 2003/2// PY - 2003/2// ER - TY - RPRT TI - Performance modeling of memory latency hiding techniques AU - Zhou, H. AU - Conte, T.M. A3 - Department of Electrical and Computer Engineering, North Carolina State University DA - 2003/1// PY - 2003/1// M3 - Technical Report, PB - Department of Electrical and Computer Engineering, North Carolina State University ER - TY - CONF TI - Extending OpenMP to support slipstream execution mode AU - Ibrahim, K.Z. AU - Byrd, G.T. 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 - 2003/// C3 - Proceedings - International Parallel and Distributed Processing Symposium, IPDPS 2003 DA - 2003/// DO - 10.1109/IPDPS.2003.1213119 SP - 10 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33847296781&partnerID=MN8TOARS ER - TY - CONF TI - A new introductory laboratory course for electrical and computer engineering AU - Öztürk, M.C. AU - Trussell, J. AU - Townsend, C. AU - Byrd, G. AU - Mortazavi, A. AU - Baran, M. AU - Conte, T. AU - O’Neal, B. AU - Bilbro, G. AU - Brickley, J. C2 - 2003/// C3 - ASEE Annual Conference Proceedings DA - 2003/// SP - 11378-11391 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-8744285585&partnerID=MN8TOARS ER - TY - RPRT TI - Code size aware compilation for real-time applications AU - Zhou, H. A3 - Computer Science Department, University of Central Florida DA - 2003/7// PY - 2003/7// M3 - Technical Report PB - Computer Science Department, University of Central Florida ER - TY - CONF TI - Enhancing Memory Level Parallelism via Recovery-Free Value Prediction AU - Zhou, H. AU - Conte, T.M. C2 - 2003/6// C3 - The 2003 International Conference on Supercomputing (ICS'03) DA - 2003/6// SP - 326–335 ER - TY - CONF TI - Welcome from the general chair AU - Lunardi, L. AU - Welser, J. AU - Candelaria, J. C2 - 2003/// C3 - Technical Digest - International Electron Devices Meeting DA - 2003/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0842266682&partnerID=MN8TOARS ER - TY - CONF TI - Plenary session AU - Lunardi, L. AU - Welser, J. C2 - 2003/// C3 - Technical Digest - International Electron Devices Meeting DA - 2003/// SP - 1 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0842288304&partnerID=MN8TOARS ER - TY - CONF TI - Tunable Dispersion Compensation at 10Gb/s and 40Gb/S Using Multicavity All-Pass Etalons AU - Moss, D. AU - Lunardi, L. AU - Lamont, M. AU - Randall, G. AU - Colbourne, P. AU - Chandrasekhar, S. AU - Buhl, L. AU - Hulse, C. C2 - 2003/// C3 - Conference on Optical Fiber Communication, Technical Digest Series DA - 2003/// VL - 86 SP - 162-163 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1642524225&partnerID=MN8TOARS ER - TY - CONF TI - Student generated course demos AU - Heath, R.W. AU - Schmidt, K.J. AB - Actively engaging engineering students in classroom instruction often results in project-centered activities. Generally these projects are selected because of student interest or topic availability. In an advanced graduate level course, EE 381K-9 Advanced Digital Signal Processing, in the Department of Electrical Engineering at The University of Texas at Austin, students are assembling technology-based projects that will be used by other students in the class and in subsequent years. Thus, these projects serve a dual educational purpose: to teach those students who are creating them and to serve as resources to teach future students. This paper describes some of the challenges of developing student generated educational projects and course demos. Outcomes and observations are presented based on a trial run in the fall 2002 class. Specific topics such as the parameters of the assignment, necessary incentives, and mechanisms for collecting feedback are discussed. Numerous suggestions for incorporating these ideas into other classes are provided. C2 - 2003/// C3 - Proceedings - Frontiers in Education Conference, FIE DA - 2003/// DO - 10.1109/FIE.2003.1264663 VL - 2 SP - F1B13-F1B18 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84946072134&partnerID=MN8TOARS ER - TY - JOUR TI - Spatial multiplexing in correlated fading via the virtual channel representation T2 - IEEE Journal on Selected Areas in Communications AB - Spatial multiplexing techniques send independent data streams on different transmit antennas to maximally exploit the capacity of multiple-input multiple-output (MIMO) fading channels. Most existing multiplexing techniques are based on an idealized MIMO channel model representing a rich scattering environment. Realistic channels corresponding to scattering clusters exhibit correlated fading and can significantly compromise the performance of such techniques. In this paper, we study the design and performance of spatial multiplexing techniques based on a virtual representation of realistic MIMO fading channels. Since the nonvanishing elements of the virtual channel matrix are uncorrelated, they capture the essential degrees of freedom in the channel and provide a simple characterization of channel statistics. In particular, the pairwise-error probability (PEP) analysis for correlated channels is greatly simplified in the virtual representation. Using the PEP analysis, various precoding schemes are introduced to improve performance in virtual channels. Unitary precoding is proposed to provide robustness to unknown channel statistics. Nonunitary precoding techniques are proposed to exploit channel structure when channel statistics are known at the transmitter. Numerical results are presented to illustrate the attractive performance of the precoding techniques. DA - 2003/// PY - 2003/// DO - 10.1109/JSAC.2003.810361 VL - 21 IS - 5 SP - 856-866 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0037560778&partnerID=MN8TOARS KW - beamforming KW - correlated channels KW - diversity KW - precoding KW - space-time coding KW - spatial multiplexing KW - virtual channel representation ER - TY - CONF TI - Student generated course demos C2 - 2003/// C3 - Proceedings - Frontiers in Education Conference DA - 2003/// VL - 2 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1642560926&partnerID=MN8TOARS ER - TY - CONF TI - Optimal CDMA signature sequences, inverse eigenvalue problems and alternating minimization C2 - 2003/// C3 - IEEE International Symposium on Information Theory - Proceedings DA - 2003/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0141938660&partnerID=MN8TOARS ER - TY - CONF TI - Limited feedback precoding for spatial multiplexing systems using linear receivers C2 - 2003/// C3 - Proceedings - IEEE Military Communications Conference MILCOM DA - 2003/// VL - 1 SP - 627-632 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3142719862&partnerID=MN8TOARS ER - TY - CONF TI - Spatially greedy scheduling in multi-user MIMO wireless systems C2 - 2003/// C3 - Conference Record of the Asilomar Conference on Signals, Systems and Computers DA - 2003/// VL - 1 SP - 982-986 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4143137960&partnerID=MN8TOARS ER - TY - CONF TI - Physical layer characterization of smart-antenna equipped mobile ad-hoc network nodes in an urban environment C2 - 2003/// C3 - Proceedings - IEEE Military Communications Conference MILCOM DA - 2003/// VL - 2 SP - 1376-1381 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3142717651&partnerID=MN8TOARS ER - TY - CONF TI - Limiting Queueing Models for Scheduling in Multi-user MIMO Wireless Systems C2 - 2003/// C3 - Proceedings of the Second IASTED International Conference on Communications, Internet, and Information Technology DA - 2003/// SP - 418-423 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1542433943&partnerID=MN8TOARS ER - TY - CONF TI - Limited Feedback Precoding for Spatial Multiplexing Systems C2 - 2003/// C3 - GLOBECOM - IEEE Global Telecommunications Conference DA - 2003/// VL - 4 SP - 1857-1861 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0842310888&partnerID=MN8TOARS ER - TY - JOUR TI - Grassmannian frames with applications to coding and communication T2 - Applied and Computational Harmonic Analysis AB - For a given class F of unit norm frames of fixed redundancy we define a Grassmannian frame as one that minimizes the maximal correlation |〈fk,fl〉| among all frames {fk}k∈I∈F. We first analyze finite-dimensional Grassmannian frames. Using links to packings in Grassmannian spaces and antipodal spherical codes we derive bounds on the minimal achievable correlation for Grassmannian frames. These bounds yield a simple condition under which Grassmannian frames coincide with unit norm tight frames. We exploit connections to graph theory, equiangular line sets, and coding theory in order to derive explicit constructions of Grassmannian frames. Our findings extend recent results on unit norm tight frames. We then introduce infinite-dimensional Grassmannian frames and analyze their connection to unit norm tight frames for frames which are generated by group-like unitary systems. We derive an example of a Grassmannian Gabor frame by using connections to sphere packing theory. Finally we discuss the application of Grassmannian frames to wireless communication and to multiple description coding. DA - 2003/// PY - 2003/// DO - 10.1016/S1063-5203(03)00023-X VL - 14 IS - 3 SP - 257-275 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0242323185&partnerID=MN8TOARS ER - TY - CONF TI - Grassmannian beamforming for multiple-input multiple-output wireless systems C2 - 2003/// C3 - IEEE International Conference on Communications DA - 2003/// VL - 4 SP - 2618-2622 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0038648277&partnerID=MN8TOARS ER - TY - JOUR TI - Equal gain transmission in multiple-input multiple-output wireless systems T2 - IEEE Transactions on Communications AB - Multiple-input multiple-output (MIMO) wireless systems are of interest due to their ability to provide substantial gains in capacity and quality. The paper proposes equal gain transmission (EGT) to provide diversity advantage in MIMO systems experiencing Rayleigh fading. The applications of EGT with selection diversity combining, equal gain combining, and maximum ratio combining are addressed. It is proven that systems using EGT with any of these combining schemes achieve full diversity order when transmitting over a memoryless, flat-fading Rayleigh matrix channel with independent entries. Since, in practice, full channel knowledge at the transmitter is difficult to realize, a quantized version of EGT is proposed. An algorithm to construct a beamforming vector codebook that guarantees full diversity order is presented. Monte-Carlo simulation comparisons with various beamforming and combining systems illustrate the performance as a function of quantization. DA - 2003/// PY - 2003/// DO - 10.1109/TCOMM.2003.814195 VL - 51 IS - 7 SP - 1102-1110 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0042524487&partnerID=MN8TOARS KW - diversity methods KW - equal gain transmission (EGT) KW - multiple-input multiple-output (MIMO) systems KW - Rayleigh channels ER - TY - JOUR TI - Grassmannian beamforming for multiple-input multiple-output wireless systems T2 - IEEE Transactions on Information Theory AB - Transmit beamforming and receive combining are simple methods for exploiting the significant diversity that is available in multiple-input multiple-output (MIMO) wireless systems. Unfortunately, optimal performance requires either complete channel knowledge or knowledge of the optimal beamforming vector; both are hard to realize. In this article, a quantized maximum signal-to-noise ratio (SNR) beamforming technique is proposed where the receiver only sends the label of the best beamforming vector in a predetermined codebook to the transmitter. By using the distribution of the optimal beamforming vector in independent and identically distributed Rayleigh fading matrix channels, the codebook design problem is solved and related to the problem of Grassmannian line packing. The proposed design criterion is flexible enough to allow for side constraints on the codebook vectors. Bounds on the codebook size are derived to guarantee full diversity order. Results on the density of Grassmannian line packings are derived and used to develop bounds on the codebook size given a capacity or SNR loss. Monte Carlo simulations are presented that compare the probability of error for different quantization strategies. DA - 2003/// PY - 2003/// DO - 10.1109/TIT.2003.817466 VL - 49 IS - 10 SP - 2735-2747 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0242334025&partnerID=MN8TOARS KW - diversity methods KW - Grassmannian line packing KW - limited feedback KW - multiple-input multiple-output (MIMO) systems KW - Rayleigh channels ER - TY - JOUR TI - Erratum: Equal gain transmission in multiple-input multiple-output wireless systems (IEEE Trans. Commun. (2003) 51 (694-703)) T2 - IEEE Transactions on Communications DA - 2003/// PY - 2003/// DO - 10.1109/TCOMM.2003.818386 VL - 51 IS - 9 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0141989510&partnerID=MN8TOARS ER - TY - CONF TI - A symbol estimation scheme for Alamouti coded OFDM systems C2 - 2003/// C3 - Proceedings - IEEE Military Communications Conference MILCOM DA - 2003/// VL - 2 SP - 1225-1230 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3142749994&partnerID=MN8TOARS ER - TY - CONF TI - Joint space-time interference cancellation and channel shortening C2 - 2003/// C3 - Conference Record of the Asilomar Conference on Signals, Systems and Computers DA - 2003/// VL - 1 SP - 32-36 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4143075669&partnerID=MN8TOARS ER - TY - CONF TI - Grassmannian Signatures for CDMA Systems C2 - 2003/// C3 - Conference Record / IEEE Global Telecommunications Conference DA - 2003/// VL - 3 SP - 1553-1557 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0842310825&partnerID=MN8TOARS ER - TY - CONF TI - CDMA signature sequences with low peak-to-average-power ratio via alternating projection C2 - 2003/// C3 - Conference Record of the Asilomar Conference on Signals, Systems and Computers DA - 2003/// VL - 1 SP - 475-479 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4143116538&partnerID=MN8TOARS ER - TY - CONF TI - Dual-mode antenna selection for spatial multiplexing systems with linear receivers C2 - 2003/// C3 - Conference Record of the Asilomar Conference on Signals, Systems and Computers DA - 2003/// VL - 1 SP - 1085-1089 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4143086337&partnerID=MN8TOARS ER - TY - CONF TI - A decision directed receiver for alamouti coded OFDM systems C2 - 2003/// C3 - IEEE Vehicular Technology Conference DA - 2003/// VL - 58 SP - 662-665 M1 - 1 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4143073630&partnerID=MN8TOARS ER - TY - JOUR TI - A Decision-Directed Receiver for Alamouti Coded OFDM Systems T2 - IEICE Transactions on Communications DA - 2003/// PY - 2003/// VL - E86-B IS - 10 SP - 3141-3143 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0242412915&partnerID=MN8TOARS ER - TY - JOUR TI - Design and implementation of a series voltage sag compensator under practical utility conditions AU - Cheng, P.-T. AU - Huang, C.-C. AU - Pan, C.-C. AU - Bhattacharya, S. T2 - IEEE Transactions on Industry Applications AB - Voltage sags have become one of the most important power quality concerns in recent years. According to survey results across the US, voltage sags and short-duration power outages account for 92% of power quality problems encountered by industrial customers. Voltage sags often cause undervoltage faults in various sensitive loads and subsequently interrupt the manufacturing processes. Such interruptions often inflict severe losses for industries. In Taiwan, ROC, most high-tech manufacturers use uninterruptible power supplies to avoid interruptions, but the cost effectiveness of such an approach remains unclear. As the utility grid continues to improve the reliability of electric power, the inverter-based voltage sag compensator has become a viable solution to prevent production interruptions resulting from voltage sags. The existing sag compensation systems accomplish a fast response within a small fraction of a fundamental cycle by tracking the line voltages closely, and switch on the compensator whenever the voltage waveforms deviate from the normal values. However, the utility voltages often contain transient spikes with amplitudes up to 200% resulting from switching of power-factor-correction capacitors, circuit breakers switchings, lightning strikes, and so on. Such transient disturbances may trigger the sag compensator into operation if its controller is very sensitive. The switching frequency of the sag compensator inverter is inadequate to compensate the narrow pulses of voltage spikes. Furthermore, the power semiconductor devices (like insulated gate bipolar transistors) of the inverter may also be damaged due to overvoltage by the surges. In this paper, a brief overview of power quality issues of a high-tech industry park in Taiwan is provided to validate the need for ride-through technologies. A synchronous-reference-frame-based controller for the inverter-based voltage sag compensator is also presented. A sag detection mechanism is included in the controller for correct and prompt identification of voltage sags. Disturbances like voltage spikes are attenuated to avoid any false triggering of the compensator. The overall system responds to voltage sags and restores the voltage back to balanced 1.0 pu for critical loads within one-eighth to one-fourth of a cycle, which meet the requirement of industry standards like the SEMI-F47 standard. Simulation and laboratory test results are presented to verify the functionality of the proposed system. DA - 2003/// PY - 2003/// DO - 10.1109/TIA.2003.811780 VL - 39 IS - 3 SP - 844-853 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0038487357&partnerID=MN8TOARS KW - capacitor switching transients KW - dynamic voltage restorer KW - power quality KW - voltage sag ER - TY - CONF TI - Space-time pre-RAKE multiuser transmitter precoding for DS-CDMA systems AU - Guncavdi, S. AU - Duel-Hallen, A. C2 - 2003/// C3 - 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484) CY - Piscataway, NJ, USA DA - 2003/// VL - Vol.4 SP - 2411 - 15 ER - TY - CONF TI - Long Range Channel Prediction and Adaptive Transmission for Frequency Hopping Communications AU - Ming, L. AU - Duel-Hallen, A. C2 - 2003/10// C3 - Proceedings of 41st Annual Allerton Conference on Communication, Control and Computing CY - Monticello, Illinois DA - 2003/10// SP - 1-10 M1 - V.C ER - TY - CONF TI - Tomlinson -- Harashima Transmitter Precoding for Synchronous Multiuser Communications AU - Liu, J. AU - Duel-Hallen, A. C2 - 2003/3// C3 - Proceedings of 37th Annual Conference on Information Sciences and Systems, CISS'03 CY - Baltimore, MD DA - 2003/3// SP - 1-6 M1 - 60 ER - TY - CONF TI - Pre-RAKE Multiuser Transmitter Precoding for DS/CDMA Systems AU - Guncavdi, S. AU - Duel-Hallen, A. C2 - 2003/3// C3 - Proceedings of 37th Annual Conference on Information Sciences and Systems, CISS'03 CY - Baltimore, MD DA - 2003/3// SP - 1-6 M1 - 169 ER - TY - CHAP TI - Fading Channels AU - Duel-Hallen, A. T2 - the Wiley Encyclopedia of Telecommunications A2 - Proakis, J. G. PY - 2003/// SP - 781-789 PB - John Wiley&Sons, Inc. ER - TY - JOUR TI - Performance evaluation of electric distribution utilities based on data envelopment analysis AU - Pahwa, A. AU - Feng, Xiaoming AU - Lubkeman, D. T2 - IEEE Transactions on Power Systems AB - In this paper, a method for benchmarking performance of electric distribution utilities based on data envelopment analysis (DEA) is presented. Basic theory of DEA is followed by case studies addressing performance analysis of the 50 largest (based on megawatt-hour sales) electric distribution utilities in the U.S. The results include performance efficiency, gaps in inputs and outputs of inefficient utilities, sensitivity-based classification of utilities, and a gap report. Also, peer-to-peer comparison of inefficient with efficient utilities is provided. Based on these results, inefficient utilities can develop strategic plans to improve performance. DA - 2003/2// PY - 2003/2// DO - 10.1109/tpwrs.2002.800986 VL - 18 IS - 1 SP - 400-405 J2 - IEEE Trans. Power Syst. LA - en OP - SN - 0885-8950 UR - http://dx.doi.org/10.1109/tpwrs.2002.800986 DB - Crossref KW - data envelopment analysis KW - decision making KW - gap analysis KW - performance benchmarking KW - strategic planning ER - TY - RPRT TI - Security Benefits of Renewable Generation: A Case Study AU - Lu, N. AU - Warwick, W.M. AU - Steese, J.G.De AU - Arey, S.J. AU - Dagle, J.E. AU - Jarrell, D.B. AU - Weimar, M.R. A3 - Prepared for U.S. Air Force Civil Engineering Support Agency Headquarters, Tyndall Air Force Base DA - 2003/// PY - 2003/// PB - Prepared for U.S. Air Force Civil Engineering Support Agency Headquarters, Tyndall Air Force Base ER - TY - CONF TI - A multi-layer Petri net model for deregulated electric power systems AU - Lu, Ning AU - Chow, J.H. AU - Desrochers, A.A. T2 - 2002 American Control Conference AB - This paper proposes a hybrid multilayer Petri net model for electric power systems. The base layer is the physical layer, which represents the physical flow in a power system. On top of it are information layers to model information flows, which schedule the physical flow via discrete tokens. In between, there is an interface layer coded as programs and functioning as a control agent. An extension of continuous Petri nets, called a variable arc weighting Petri net (VAWPN), is introduced to simulate the physical layer, in which vector tokens are used to match the information flows to the physical flows. The operation of a VAWPN is presented. A three-zone example of a power system dispatch model is used to illustrate the concepts. C2 - 2003/6/25/ C3 - Proceedings of the 2002 American Control Conference (IEEE Cat. No.CH37301) DA - 2003/6/25/ DO - 10.1109/acc.2002.1024858 PB - American Automatic Control Council SN - 0780372980 UR - http://dx.doi.org/10.1109/acc.2002.1024858 DB - Crossref ER - TY - CONF TI - AC Coupled Interconnect for Dense 3-D Systems AU - Xu, Jian AU - Mick, Stephen AU - Wilson, John AU - Luo, Lei AU - Chandrasakhar, Karthik AU - Franzon, Paul T2 - 2003 IEEE Nuclear Science Symposium Conference AB - This paper presents the potential application of AC Coupled Interconnect (ACCI) for dense three-dimensional (3-D) ICs. The concept of inductive ACCT for 3-D stacking ICs has been proposed. Combined with the "through vias" technology, the inductive ACCI can provide small pitch vertical interconnects, as well as an excellent thermal solution for dense 3-D ICs. The transformer modeling and transceiver circuit design have also been investigated. The 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 input stream consumes 15.6 mW power. C2 - 2003/10/19/ C3 - Proceedings of the IEEE Conference on Nuclear Science and Imaging CY - Portland, OR, USA DA - 2003/10/19/ PY - 2003/10/19/ DO - 10.1109/NSSMIC.2003.1352013 PB - IEEE SN - 0-7803-8257-9 ER - TY - CONF TI - High Frequency, High Density Interconnect Using AC Coupling AU - Franzon, Paul AU - Kingon, Angus AU - Mick, Stephen AU - Wilson, John AU - Luo, Lei AU - Chandrasakhar, Karthik AU - Xu, Jian AU - Bonafede, Salvatore AU - Huffman, Alan AU - Statler, Chad AU - LaBennett, Richard C2 - 2003/12// C3 - Fall MRS Conference CY - Boston, MA DA - 2003/12// DO - 10.1557/PROC-783-B6.1 ER - TY - CONF TI - The development of a macro-modeling tool to develop IBIS models AU - Varma, A. AU - Glaser, A. AU - Lipa, S. AU - Steer, M. AU - Franzon, P. T2 - IEEE Conference on Electrical Performance of Electrical Packaging AB - 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. C2 - 2003/10/27/ C3 - Proceedings of the IEEE Conference on Electrical Performance of Electronic Packaging CY - Princeton, NJ, USA DA - 2003/10/27/ PY - 2003/10/27/ DO - 10.1109/EPEP.2003.1250049 SP - 177–280 PB - IEEE SN - 0-7803-8128-9 ER - TY - CONF TI - A low power PSK receiver for space applications in 0.35 µm CMOS AU - Yuce, M.R. AU - Liu, W. AU - Damiano, J. AU - Bharat, B. AU - Franzon, P.D. AU - Nugan, N.S. T2 - IEEE 2003 Custom Integrated Circuits Conference AB - An all-digital and low power PSK baseband receiver circuit using silicon on insulator technology (SOI) is designed for space applications. The receiver employs double differential detection to improve the receiver's robustness to Doppler effect as well as a 1 bit A/D at the front to reduce complexity and power. Operating at a UHF frequency (435 MHz), the receiver supports a wide range of data rates (0.1-100 kb/s). From test results, the power consumption of the baseband circuit, including the 1 bit A/D converter is below 1 mW for data rates up to 100 kb/s. C2 - 2003/9/24/ C3 - Proceedings of the IEEE Custom Integrated Circuits Conference CY - San Jose, CA, USA DA - 2003/9/24/ PY - 2003/9/24/ DO - 10.1109/CICC.2003.1249381 SP - 155–158 PB - IEEE SN - 0-7803-7842-3 ER - TY - CONF TI - CAD flows for chip-package codesign AU - Varma, A. AU - Glaser, A. AU - Franzon, P. T2 - Electrical Performance of Electrical Packaging AB - A unified method is presented for layout and package design implemented within a commercial design environment that will reduce design time and enable chip-package codesign. C2 - 2003/10// C3 - Proceedings of the IEEE Conference on Electrical Performance of Electronic Packaging CY - Princeton, NJ, USA DA - 2003/10// PY - 2003/10/27/ DO - 10.1109/EPEP.2003.1249989 SP - 11–14 PB - IEEE SN - 0-7803-8128-9 ER - TY - CONF TI - Microsensors on a Flexible Plastic Substrate for Dissolved Oxygen Monitoring with Self-Calibration Capability AU - Kim, C.-S. AU - Sathyan, S. AU - Porterfield, D.M. AU - Nagle, H.T. T2 - PITTCON 2003 C2 - 2003/// C3 - Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy CY - Orlando, FL DA - 2003/// PY - 2003/3/9/ ER - TY - CONF TI - Silicon monolithic broadband millimeter wave radio technology AU - Gaucher, B. AU - Beukema, T. AU - Reynolds, S. AU - Floyd, B. AU - Zwick, T. AU - Pfeiffer, U. AU - Liu, D. C2 - 2003/6// C3 - International Conference on Space Mission Challenges for Information Technology DA - 2003/6// SP - 113–121 ER - TY - CONF TI - Simulation and experimental characterization of a 2-D, 3-MHz capacitive micromachined ultrasonic transducer (CMUT) array element AU - Oralkn, O. AU - Jin, X.C. AU - Degertekin, F.L. AU - Khuri-Yakub, B.T. T2 - 1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium AB - In this paper, a 400-/spl mu/m/spl times/400-/spl mu/m, 2-D capacitive micromachined ultrasonic transducer array element is experimentally characterized, and the results are found to be in agreement with theoretical predictions. As a receiver the transducer has a 1.8/spl times/10/sup -7/ nm//spl radic/Hz displacement sensitivity, and, as a transmitter, it produces 16.4 kPa/V of output pressure at the transducer surface at 3 MHz. The transducer also has more than 100% fractional bandwidth around 3 MHz, which makes it suitable for ultrasound imaging. The radiation pattern measurements indicate a 3-dB acceptance angle of /spl plusmn/35 degrees in agreement with the theoretical predictions. C2 - 2003/1/22/ C3 - 1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027) DA - 2003/1/22/ DO - 10.1109/ultsym.1999.849200 PB - IEEE SN - 0780357221 UR - http://dx.doi.org/10.1109/ultsym.1999.849200 DB - Crossref ER - TY - CONF TI - Broadband capacitive micromachined ultrasonic transducers ranging from 10 kHz to 60 MHz for imaging arrays and more AU - Ergun, A.S. AU - Huang, Yongli AU - Cheng, C.-H. AU - Oralkan, Omer AU - Johnson, J. AU - Jagannathan, H. AU - Demirci, U. AU - Yaralioglu, G.G. AU - Karaman, M. AU - Khuri-Yakub, B.T. AU - al. T2 - 2002 IEEE International Ultrasonics Symposium AB - Capacitive micromachined ultrasonic transducers (CMUTs) have long been studied. Past research has shown that CMUTs indeed have remarkable features such as wide bandwidth and high efficiency. This paper introduces an inclusion to the CMUT technology that uses the wafer-bonding technique to fabricate membranes on silicon. This new technology enables the fabrication of large membranes with large gaps, and expands the frequency span of CMUTs to 10 kHz in the low end. CMUT devices with different frequency spans are fabricated using both technologies, and tested. Electromechanical coupling efficiency, k/sub T//sup 2/, value as high as 0.85 and fractional immersion bandwidth as wide as 175 % are measured. C2 - 2003/12/22/ C3 - 2002 IEEE Ultrasonics Symposium, 2002. Proceedings. DA - 2003/12/22/ DO - 10.1109/ultsym.2002.1192473 PB - IEEE SN - 0780375823 UR - http://dx.doi.org/10.1109/ultsym.2002.1192473 DB - Crossref ER - TY - CONF TI - Volumetric imaging using 2D capacitive micromachined ultrasonic transducer arrays (CMUTs): initial results AU - Oralkan, O. AU - Ergun, A.S. AU - Cheng, Ching-hsiang AU - Johnson, J.A. AU - Karaman, M. AU - Lee, T.H. AU - Khuri-Yakub, B.T. T2 - 2002 IEEE International Ultrasonics Symposium AB - This paper presents the first volumetric images obtained using a 2D CMUT array with through-wafer via interconnects. An 8/spl times/6-element portion of a 32/spl times/64-element array flip-chip bonded onto a glass fanout chip was used in the experiments. This study experimentally demonstrates that 2D CMUT arrays can be fabricated with high yield using silicon micromachining processes, individual electrical connections can be provided using through-wafer interconnects, and the flip-chip bonding technique can be used to integrate the dense 2D arrays with electronic circuits for practical imaging applications. C2 - 2003/12/22/ C3 - 2002 IEEE Ultrasonics Symposium, 2002. Proceedings. DA - 2003/12/22/ DO - 10.1109/ultsym.2002.1192483 PB - IEEE SN - 0780375823 UR - http://dx.doi.org/10.1109/ultsym.2002.1192483 DB - Crossref ER - TY - CONF TI - Method for determining odor dispersion using instrumental and human measurements AU - Schiffman, S.S. AU - McLaughlin, B. AU - Katul, G.G. AU - Nagle, H. T. T2 - ISOEN '03 C2 - 2003/// C3 - 10th International Symposium on Olfaction and Electronic Nose Technical Digest CY - Riga, Latvia DA - 2003/// PY - 2003/// ER - TY - CONF TI - Assessing autonomic activity from the EKG related to seizure onset detection and localization AU - Quint, S.R. AU - Messenheimer, J.A. AU - Tennison, M.B. AU - Nagle, H.T. T2 - [1989] Proceedings. Second Annual IEEE Symposium on Computer-based Medical Systems AB - Methods are presented for the detection and analysis of heart period variation (HPV) in both the time domain and the frequency domain. Fractal analysis and rate-change detection procedures are used for the recognition of transients in the HPV random variable. The power spectra of HPV are used to quantify relative autonomic input to the heart, with power at high frequencies (sinus arrhythmia) sensitive to parasympathetic input and low frequency power due to a combination of sympathetic and parasympathetic activities. Spectral analysis of HPV is used to study the dynamic activity of the autonomic nervous system, under conditions observed clinically which are considered to be risk factors for sudden death in epileptics. Results and conclusions from a study of a population of epilepsy patients are also presented.< > C2 - 2003/1/7/ C3 - [1989] Proceedings. Second Annual IEEE Symposium on Computer-based Medical Systems DA - 2003/1/7/ DO - 10.1109/cbmsys.1989.47350 PB - IEEE Comput. Soc. Press SN - 0818619600 UR - http://dx.doi.org/10.1109/cbmsys.1989.47350 DB - Crossref ER - TY - CONF TI - Silicon based electrode arrays AU - Ash, R.B. AU - Wortman, J.J. AU - Nagle, H.T. AU - Buchanan, J.W. T2 - Images of the Twenty-First Century. Annual International Engineering in Medicine and Biology Society AB - The manufacture of a three-dimensional, silicon-based, high-density electrode array with potential biomedical applications is described. Microelectronic fabrication techniques are used to produce an array of regularly spaced electrodes with sensing sites on the order of tens of micrometers. This electrode array consists of a pin-cushion of silicon posts set in an insulating substrate and plated with thin-film conductors and dielectrics. Since it is based on silicon, the array is suitable for integrated data processing and multiplexing, which would allow a large number of electrodes to be monitored simultaneously.< > C2 - 2003/1/13/ C3 - Images of the Twenty-First Century. Proceedings of the Annual International Engineering in Medicine and Biology Society DA - 2003/1/13/ DO - 10.1109/iembs.1989.95685 PB - IEEE UR - http://dx.doi.org/10.1109/iembs.1989.95685 DB - Crossref ER - TY - CONF TI - Overview of quality assurance for medical devices AU - Nagle, H.T. T2 - 1992 International Biomedical Engineering Days AB - Medical devices can have very stringent performance requirements. The life of a critically ill patient can be determined by the quality of the monitoring and therapeutic devices being used in his or her treatment. But how is quality guaranteed? What are the characteristics of a medical device that determine its quality? The author discusses the methods used for designing quality into medical devices.< > C2 - 2003/1/2/ C3 - Proceedings of the 1992 International Biomedical Engineering Days DA - 2003/1/2/ DO - 10.1109/ibed.1992.247093 PB - IEEE SN - 0780307437 UR - http://dx.doi.org/10.1109/ibed.1992.247093 DB - Crossref ER - TY - CONF TI - AC Coupled Interconnect for High-Density High-Bandwidth Packaging AU - Franzon, Paul AU - Mick, Stephen AU - Wilson, John AU - Luo, Lei AU - Chandrasakhar, Karthik T2 - 2003 International Conference on Solid State Devices and Materials AB - AC Coupled Interconnection (ACCI), in conjunction with buried solder bump technology, provides a method to achieve signal I/O pitches of less than 100 μm and signaling rates greater than 3 Gbps per I/O on integrated circuits, while preserving excellent signal integrity. This paper presents a summary of approaches and status capacitive and inductive versions of AC Coupled Interconnect Systems. C2 - 2003/// C3 - Extended Abstracts of the 2003 International Conference on Solid State Devices and Materials CY - Perth, Australia DA - 2003/// DO - 10.7567/ssdm.2003.g-6-1 SP - 67–69 PB - The Japan Society of Applied Physics UR - http://dx.doi.org/10.7567/ssdm.2003.g-6-1 DB - Crossref ER - TY - CONF TI - Development of a simple biosensor mapping technology for epicardial activation in rodent hearts AU - Andersen, K. AU - Wyrick, D. AU - Fiering, J. AU - Nagle, H.T. AU - Martin, D. AU - Johnson, T.K. T2 - First Joint BMES/EMBS Conference AB - The development of a simple mapping technology for viewing the activation wavefronts of rodent hearts is currently ongoing. The successful development of an electrophysiologic (EP) electrode array biosensor for rodent hearts has been the foundation of this work. Our goal is to develop a simple method to process EP data obtained by the biosensor and present the data in a graphical format suitable for additional quantitative and qualitative analysis. C2 - 2003/1/20/ C3 - Proceedings of the First Joint BMES/EMBS Conference. 1999 IEEE Engineering in Medicine and Biology 21st Annual Conference and the 1999 Annual Fall Meeting of the Biomedical Engineering Society (Cat. No.99CH37015) DA - 2003/1/20/ DO - 10.1109/iembs.1999.802213 PB - IEEE SN - 0780356748 UR - http://dx.doi.org/10.1109/iembs.1999.802213 DB - Crossref ER - TY - CONF TI - Two-Part Codes with Low Worst-Case Redundancies for Distributed Compression of Bernoulli Sequences AU - Baron, D. AU - Bresler, Y. AU - Mihcak, M.K. T2 - CISS 2003 C2 - 2003/3// C3 - Proceedings of 37th Annual Conference on Information Sciences and Systems DA - 2003/3// ER - TY - CONF TI - A 900-MHz, 0.8-μm CMOS low noise amplifier with 1.2-dB noise figure AU - Floyd, B.A. AU - Mehta, J. AU - Gamero, C. AU - Kenneth, K.O. T2 - IEEE 1999 Custom Integrated Circuits Conference AB - A 900-MHz single-stage low noise amplifier (LNA), requiring one external inductor and matched to 50-/spl Omega/ at both the input and output, has been implemented in a standard digital 0.8-/spl mu/m CMOS technology. Measured noise figures for the LNA in package are 2 dB at 6.2 mW, 1.78 dB at 8.1 mW, 1.5 dB at 13.2 mW, and 1.2 dB at 30 mW. At 30 mW and V/sub DD/=3.0 V, the LNA has a power gain of 14.5 dB, and an IIP3 of -1 dBm. At 6.2 mW and V/sub DD/=2.7 V, the LNA has a power gain of 9.4 dB, and an IIP3 of -3.8 dBm. C2 - 2003/1/20/ C3 - Proceedings of the IEEE 1999 Custom Integrated Circuits Conference (Cat. No.99CH36327) DA - 2003/1/20/ DO - 10.1109/cicc.1999.777367 PB - IEEE SN - 0780354435 UR - http://dx.doi.org/10.1109/cicc.1999.777367 DB - Crossref ER - TY - CONF TI - The projected power consumption of a wireless clock distribution system and comparison to conventional distribution systems AU - Floyd, B.A. AU - O, K.K. T2 - IEEE 1999 International Interconnect Technology Conference AB - A wireless interconnect system has been proposed for global clock signal distribution. The system transmits and receives signals at 20 GHz or higher. The received signal is then amplified, frequency divided to 4 GHz or lower, and buffered to provide a clock signal to the local clock distribution system. An analysis comparing the projected power dissipation of a wireless clock distribution system to conventional grid-based and H-tree based distribution systems for 0.1 /spl mu/m generation microprocessors is performed, based on the total capacitive loading of the global distribution system. The results show that in terms of power dissipation, the wireless clock distribution system should be comparable to conventional systems. C2 - 2003/1/20/ C3 - Proceedings of the IEEE 1999 International Interconnect Technology Conference (Cat. No.99EX247) DA - 2003/1/20/ DO - 10.1109/iitc.1999.787135 PB - IEEE SN - 0780351746 UR - http://dx.doi.org/10.1109/iitc.1999.787135 DB - Crossref ER - TY - CONF TI - Jitter in a wireless clock distribution system AU - Dickson, T. AU - Floyd, B. AU - O, K. T2 - IEEE 2002 International Interconnect Technology Conference AB - The jitter of a transmitted wireless clock signal has been measured and found to behave much like jitter of conventionally distributed clock signals. Noise from nearby digital circuits can degrade receiver sensitivity by reducing LNA gain and shifting the divider self-oscillation frequency. This increases clock jitter and, in extreme conditions, can cause failure in the clock receiver circuits to lock on to the transmitted clock signal. The clock can be re-locked by increasing the transmitted power. C2 - 2003/6/25/ C3 - Proceedings of the IEEE 2002 International Interconnect Technology Conference (Cat. No.02EX519) DA - 2003/6/25/ DO - 10.1109/iitc.2002.1014917 PB - IEEE SN - 0780372166 UR - http://dx.doi.org/10.1109/iitc.2002.1014917 DB - Crossref ER - TY - CONF TI - Propagation layers for intra-chip wireless interconnection compatible with packaging and heat removal AU - Guo, Xiaoling AU - Caserta, J. AU - Li, R. AU - Floyd, B. AU - O, K.O. T2 - 2002 Symposium on VLSI Technology Digest of Technical Papers AB - Inserting an aluminum nitride (AlN) layer which acts as a dielectric propagating medium between a silicon wafer containing integrated antennas and a metal chuck emulating the role of a heat sink improves the antenna power transmission gain by /spl sim/8 dB at 15 GHz. AlN, with its high thermal conductivity, also alleviates the heat removal problem. With a 760-/spl mu/m AlN layer, an on-chip wireless connection is demonstrated over a 2.2-cm distance, which is 3/spl times/ the previously reported separation. C2 - 2003/6/25/ C3 - 2002 Symposium on VLSI Technology. Digest of Technical Papers (Cat. No.01CH37303) DA - 2003/6/25/ DO - 10.1109/vlsit.2002.1015378 PB - IEEE SN - 078037312X UR - http://dx.doi.org/10.1109/vlsit.2002.1015378 DB - Crossref ER - TY - CONF TI - A direct-conversion receiver IC for WCDMA mobile systems AU - Reynolds, S. AU - Floyd, B. AU - Beukema, T. AU - Zwick, T. AU - Pfeiffer, U. AU - Ainspan, H. T2 - 2002 IEEE Bipolar/BICMOS Circuits and Technology Meeting AB - A prototype design of a 2.7 V, 14.5 mA SiGe direct-conversion receiver IC for use in 3G WCDMA mobile cellular systems has been completed and measured. The design includes a bypassable LNA, a quadrature downconverter, and variable gain baseband amplifiers integrated on chip. The static sensitivity performance of the receiver IC is characterized using a software baseband processor to compute link bit-error rate. C2 - 2003/6/25/ C3 - Proceedings of the Bipolar/BiCMOS Circuits and Technology Meeting DA - 2003/6/25/ DO - 10.1109/bipol.2002.1042887 PB - IEEE SN - 0780375610 UR - http://dx.doi.org/10.1109/bipol.2002.1042887 DB - Crossref ER - TY - CONF TI - Observation of field-induced optical phonon amplification in semiconductor nanostructures AU - Liang, W. AU - Tsen, Kong-Thon F. AU - Sankey, Otto F. AU - Komirenko, Sergiy M. AU - Kim, Ki Wook AU - Kochelap, Viatcheslav A. AU - Wu, Meng-Chyi AU - Ho, Chong-Long AU - Ho, Wen-Jeng AU - Morkoc, Hadis T2 - Integrated Optoelectronics Devices A2 - Tsen, Kong-Thon F. A2 - Song, Jin-Joo A2 - Jiang, Hongxing AB - We have experimentally proven the Cerenkov generation of optical phonons by drifting electrons in a semiconductor. We observe an instability of the polar optical phonons in nanoscale semiconductors that occurs when electrons are accelerated to very high velocities by intense electric fields. The instability is observed when the electron drift velocity is larger than the phase velocity of optical phonons and rather resembles a “sonic-boom” for optical phonons. The effect is demonstrated in p-i-n semiconductor nanostructures by suing subpicosecond Raman spectroscopy. We suggest that the observed phenomena will have enormous impact on the carrier dynamics in nanoscale semiconductor devices. C2 - 2003/6/2/ C3 - Ultrafast Phenomena in Semiconductors VII DA - 2003/6/2/ DO - 10.1117/12.479278 PB - SPIE UR - http://dx.doi.org/10.1117/12.479278 DB - Crossref ER - TY - CONF TI - Coherent LO phonons generated by high-velocity electrons in two-dimensional channels and their impact on carrier transport AU - Komirenko, S.M. AU - Kim, K.W. AU - Kochelap, V.A. AU - Stroscio, M.A. T2 - 2002 2nd IEEE Conference on Nanotechnology AB - We show that Cerenkov generation of confined LO phonons by drifting electrons can be achieved in biased quantum wells (QWs). Both linear and nonlinear regimes of phonon generation are analyzed. The kinetic parameters of the drifting electrons are estimated by using momentum and energy balance equations for electron scattering by the confined optical phonons. Our findings suggest that high efficiency electrical generation of coherent optical phonons can be realized in two-dimensional structures with high drift velocities, such as AlAs/GaAs/AlAs and GaSb/InSb/GaSb QWs. Due to high conversion efficiency, the effect of current driven phonon generation can be an important mechanism of current suppression in two-dimensional channels where its contribution to saturation of current-voltage characteristics can compete with the contribution of intervalley transitions. C2 - 2003/6/25/ C3 - Proceedings of the 2nd IEEE Conference on Nanotechnology DA - 2003/6/25/ DO - 10.1109/NANO.2002.1032107 PB - IEEE SN - 0780375386 UR - http://dx.doi.org/10.1109/NANO.2002.1032107 DB - Crossref ER - TY - JOUR TI - A direct-conversion receiver integrated circuit for WCDMA mobile systems AU - Reynolds, S. K. AU - Floyd, B. A. AU - Beukema, T. J. AU - Zwick, T. AU - Pfeiffer, U. R. AU - Ainspan, H. A. T2 - IBM Journal of Research and Development AB - A prototype of a 3-V SiGe direct-conversion receiver integrated circuit for use in third-generation (3G) WCDMA mobile cellular systems has been completed. The goal of its design was to minimize current draw while meeting WCDMA receiver rf specifications with margin. The design includes a bypassable low-noise amplifier, quadrature downconverter, and first-stage variable-gain baseband amplifiers integrated on chip. The design is optimized for use with a single-ended off-chip bandpass surface-acoustic-wave filter with no external matching components. The prototype design represents a first step toward a fully integrated monolithic WCDMA/UMTS receiver system-on-a-chip. A rigorous set of performance tests are used to characterize the noise and linearity performance of the packaged IC across its full frequency band of operation. A receiver test-bed system with a software baseband demodulator is used to determine the bit-error-rate performance of the receiver integrated circuit (IC) at sensitivity. Measured results are compared with estimated system performance requirements to determine compliance with key WCDMA rf specifications. DA - 2003/3// PY - 2003/3// DO - 10.1147/rd.472.0337 VL - 47 IS - 2.3 SP - 337-353 J2 - IBM J. Res. & Dev. OP - SN - 0018-8646 0018-8646 UR - http://dx.doi.org/10.1147/rd.472.0337 DB - Crossref ER - TY - JOUR TI - A direct-conversion receiver IC for WCDMA mobile systems AU - Reynolds, S.K. AU - Floyd, B.A. AU - Beukema, T. AU - Zwick, T. AU - Pfeiffer, U. AU - Ainspan, H. T2 - IEEE Journal of Solid-State Circuits AB - A prototype design of a 2.7-3.3-V 14.5-mA SiGe direct-conversion receiver IC for use in third-generation wide-band code-division multiple-access (3G WCDMA) mobile cellular systems has been completed and measured. The design includes a bypassable low-noise amplifier (LNA), a quadrature downconverter, a local-oscillator frequency divider and quadrature generator, and variable-gain baseband amplifiers integrated on chip. The design achieves a cascaded, LNA-referred noise figure (including an interstage surface acoustic wave filter) of 4.0 dB, an in-band IIP3 of -18.6 dBm, and local-oscillator leakage at the LNA input of -112 dBm. The static sensitivity performance of the receiver IC is characterized using a software baseband processor to compute link bit-error rate. DA - 2003/9// PY - 2003/9// DO - 10.1109/jssc.2003.815914 VL - 38 IS - 9 SP - 1555-1560 J2 - IEEE J. Solid-State Circuits LA - en OP - SN - 0018-9200 UR - http://dx.doi.org/10.1109/jssc.2003.815914 DB - Crossref KW - code division multiaccess KW - land mobile radio KW - cellular systems KW - receivers KW - mixers KW - low noise amplifiers (LNAs) KW - BiCMOS KW - direct conversion ER - TY - JOUR TI - A multichannel pipeline analog-to-digital converter for an integrated 3-d ultrasound imaging system AU - Kaviani, K. AU - Oralkan, O. AU - Khuri-Yakub, P. AU - Wooley, B.A. T2 - IEEE Journal of Solid-State Circuits AB - An 8-channel 10-bit pipeline analog-to-digital converter, designed for use in an integrated three-dimensional ultrasound imaging system, has been implemented in a 0.25-μm CMOS technology. Two parallel multiplexing sample-and-hold stages are employed to multiplex a total of eight adjacent ultrasound channels, each sampled at 20 MHz. The sampled and multiplexed signals are fed into two parallel time-interleaved pipeline paths, each operating at 80 MHz. The two parallel pipelines are subsequently multiplexed into a single pipeline operating at 160 MHz to conserve area and reduce complexity. An experimental prototype of the proposed architecture occupies less than 4 mm 2 of active silicon area and shows a peak signal-to-noise-plus-distortion ratio more than 54 dB for a 2.1-MHz input signal, while dissipating only 20 mW of analog power per input channel from a 2.5-V supply. DA - 2003/7// PY - 2003/7// DO - 10.1109/jssc.2003.813294 VL - 38 IS - 7 SP - 1266-1270 J2 - IEEE J. Solid-State Circuits LA - en OP - SN - 0018-9200 UR - http://dx.doi.org/10.1109/jssc.2003.813294 DB - Crossref KW - analog-to-digital converter (ADC) KW - mixed-signal integrated circuits KW - multichannel KW - multiplexing KW - pipeline analog-to-digital conversion KW - switched-capacitor circuits KW - ultrasound imaging ER - TY - JOUR TI - Volumetric ultrasound imaging using 2-D CMUT arrays AU - Oralkan, O. AU - Ergun, A.S. AU - Cheng, Ching-Hsiang AU - Johnson, J.A. AU - Karaman, M. AU - Lee, T.H. AU - Khuri-Yakub, B.T. T2 - IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control AB - Recently, capacitive micromachined ultrasonic transducers (CMUTs) have emerged as a candidate to overcome the difficulties in the realization of 2-D arrays for real-time 3-D imaging. In this paper, we present the first volumetric images obtained using a 2-D CMUT array. We have fabricated a 128/spl times/128-element 2-D CMUT array with through-wafer via interconnects and a 420-/spl mu/m element pitch. As an experimental prototype, a 32/spl times/64-element portion of the 128/spl times/128-element array was diced and flip-chip bonded onto a glass fanout chip. This chip provides individual leads from a central 16/spl times/16-element portion of the array to surrounding bondpads. An 8/spl times/16-element portion of the array was used in the experiments along with a 128-channel data acquisition system. For imaging phantoms, we used a 2.37-mm diameter steel sphere located 10 mm from the array center and two 12-mm-thick Plexiglas plates located 20 mm and 60 mm from the array. A 4/spl times/4 group of elements in the middle of the 8/spl times/16-element array was used in transmit, and the remaining elements were used to receive the echo signals. The echo signal obtained from the spherical target presented a frequency spectrum centered at 4.37 MHz with a 100% fractional bandwidth, whereas the frequency spectrum for the echo signal from the parallel plate phantom was centered at 3.44 MHz with a 91% fractional bandwidth. The images were reconstructed by using RF beamforming and synthetic phased array approaches and visualized by surface rendering and multiplanar slicing techniques. The image of the spherical target has been used to approximate the point spread function of the system and is compared with theoretical expectations. This study experimentally demonstrates that 2-D CMUT arrays can be fabricated with high yield using silicon IC-fabrication processes, individual electrical connections can be provided using through-wafer vias, and flip-chip bonding can be used to integrate these dense 2-D arrays with electronic circuits for practical 3-D imaging applications. DA - 2003/11// PY - 2003/11// DO - 10.1109/tuffc.2003.1251142 VL - 50 IS - 11 SP - 1581-1594 J2 - IEEE Trans. Ultrason., Ferroelect., Freq. Contr. OP - SN - 0885-3010 UR - http://dx.doi.org/10.1109/tuffc.2003.1251142 DB - Crossref ER - TY - RPRT TI - On the suitability of a new high-power lithium ion battery for hybrid electric vehicle applications AU - Lukic, SM AU - Khateeb, SA AU - Al-Hallaj, S AU - Selman, , JR AU - Emadi, A A3 - SAE Technical Paper DA - 2003/// PY - 2003/// PB - SAE Technical Paper ER - TY - CONF TI - Modeling of electric machines for automotive applications using efficiency maps AU - Lukic, SM AU - Emado, A T2 - IEEE C2 - 2003/// C3 - Proceedings: Electrical Insulation Conference and Electrical Manufacturing and Coil Winding Technology Conference (Cat. No. 03CH37480) DA - 2003/// SP - 543-550 ER - TY - RPRT TI - Effects of electrical loads on 42V automotive power systems AU - Lukic, SM AU - Emadi, A A3 - SAE Technical Paper DA - 2003/// PY - 2003/// PB - SAE Technical Paper ER - TY - JOUR TI - 2003-01-2289 On the Suitability of a New High-Power Lithium Ion Battery for Hybrid Electric Vehicle Applications AU - Lukic, SM AU - Khateeb, SA AU - Al-Hallaj, S AU - Selman, , JR AU - Emadi, A T2 - SAE SP DA - 2003/// PY - 2003/// SP - 49-54 ER - TY - JOUR TI - A Methodology and Simulator for the Study of Network Processors AU - Suryanarayanan, Deepak AU - Marshall, John AU - Byrd, Gregory T. T2 - Network Processor Design AB - Network processors (NPs) are emerging new class of processors that combine programmable ASICs and microprocessors to implement adaptive network services. NPs influence the flexibility of software solutions with the high performance of custom hardware. The development of such sophisticated hardware requires a holistic methodology that can facilitate the study of network processors and their performance with different networking applications and traffic conditions. It is noted that this combination of study techniques is essentially accomplished in the component network simulator (ComNetSim). The simulator includes both a traffic-modeling component and a detailed architectural framework that allows the study of complete networking applications under varying network traffic conditions. The chapter illustrates a weighted round robin scheduling algorithm, adapted to the Toaster architecture. It describes high-level simulator design and details the Toaster network processor and the implementation of the simulator including the cycle-accurate model of the Toaster architecture. The chapter also briefly presents the simulator organization along with performance results and analysis. DA - 2003/// PY - 2003/// DO - 10.1016/b978-155860875-7.50021-1 SP - 27-54 ER - TY - CONF TI - Seamless Handover in Buildings Using HVAC Ducts: A New System Architecture AU - Xhafa, A.E. AU - Sonthikorn, P. AU - Tonguz, O.K. AU - Nikitin, P.V. AU - Cepni, A.G. AU - Stancil, D.D. AU - Henty, B. AU - Brodtkorb, D. C2 - 2003/// C3 - Conference Record / IEEE Global Telecommunications Conference DA - 2003/// VL - 6 SP - 3093-3097 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0842267553&partnerID=MN8TOARS ER - TY - JOUR TI - Ridge waveguide as a near-field optical source AU - Itagi, A.V. AU - Stancil, D.D. AU - Bain, J.A. AU - Schlesinger, T.E. T2 - Applied Physics Letters AB - We investigate the feasibility of using a ridge waveguide at optical frequencies as a near-field optical transducer, using the finite difference time domain method. The complete electromagnetic field picture of the ridge waveguide, in the absence and presence of the irradiated medium, is presented. A power efficiency of 7% and an optical spot with full width half maximum of 50 nm×80 nm is obtained in the medium. We show that impedance considerations play a major role in the transducer-medium optical coupling. DA - 2003/// PY - 2003/// DO - 10.1063/1.1631057 VL - 83 IS - 22 SP - 4474-4476 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0348107250&partnerID=MN8TOARS ER - TY - JOUR TI - Refraction theory for planar waveguides: Modeling of a mode index integrated solid immersion lens AU - Itagi, A.V. AU - Schlesinger, T.E. AU - Stancil, D.D. T2 - Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers DA - 2003/// PY - 2003/// VL - 42 IS - 2 B SP - 740-749 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0038736855&partnerID=MN8TOARS ER - TY - CONF TI - Propagation modelling of complex HVAC networks using transfer matrix method AU - Nikitin, P.V. AU - Stancil, D.D. AU - Cepni, A.G. AU - Xhafa, A.E. AU - Tonguz, O.K. AU - Brodtkorb, D. C2 - 2003/// C3 - IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) DA - 2003/// VL - 2 SP - 126-129 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0042473203&partnerID=MN8TOARS ER - TY - JOUR TI - Propagation model for the HVAC duct as a communication channel AU - Nikitinj, P.V. AU - Stancil, D.D. AU - Cepni, A.G. AU - Tonguz, O.K. AU - Xhafa, A.E. AU - Brodtkorb, D. T2 - IEEE Transactions on Antennas and Propagation AB - Heating, ventilation, and air conditioning (HVAC) ducts in buildings are typically hollow metal pipes which can be used as waveguides to carry signals and provide network access to offices. Knowledge of channel properties is crucial to designing such a communication system. The paper presents a propagation model for a straight HVAC duct terminated at both ends. At high frequencies, this duct behaves as a multimode waveguide with a transmitting antenna coupling in and a receiving antenna coupling out. We derive a simple analytical expression for the frequency response of this channel using conventional techniques. Experimental data taken on real circular ducts excited by monopole probe antennas confirm the theoretical results. This model represents an initial step toward the development of a tool for planning a wireless distribution system using building HVAC ducts. DA - 2003/// PY - 2003/// DO - 10.1109/TAP.2003.811491 VL - 51 IS - 5 SP - 945-951 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0042703881&partnerID=MN8TOARS KW - indoor radio communication KW - monopole antennas KW - multimode waveguides KW - radio propagation KW - wireless LAN ER - TY - CONF TI - Novel mode content analysis technique for multimode waveguides AU - Nikitin, P.V. AU - Stancil, D.D. AU - Cepni, A.G. AU - Xhafa, A.E. AU - Tonguz, O.K. AU - Brodtkorb, D. C2 - 2003/// C3 - IEEE MTT-S International Microwave Symposium Digest DA - 2003/// VL - 3 SP - 1827-1830 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0043092531&partnerID=MN8TOARS ER - TY - JOUR TI - Impulse response of the HVAC duct as a communication channel AU - Nikitin, P.V. AU - Stancil, D.D. AU - Tonguz, O.K. AU - Xhafa, A.E. AU - Cepni, A.G. AU - Brodtkorb, D. T2 - IEEE Transactions on Communications AB - Heating, ventilation, and air conditioning (HVAC) ducts in buildings behave as multimode waveguides when excited at radio frequencies and thus, can be used to distribute radio signals. The channel properties of the ducts are different from the properties of a usual indoor propagation channel. In this paper, we describe physical mechanisms which affect the HVAC channel impulse response and analyze their influence on the delay spread. Those mechanisms include antenna coupling, attenuation, and three types of dispersion: intramodal, intermodal, and multipath. We analyze each type separately and explore the behavior of the delay spread as a function of distance in straight ducts. Experimental channel measurements taken on real ducts confirm the validity of our model. DA - 2003/// PY - 2003/// DO - 10.1109/TCOMM.2003.818098 VL - 51 IS - 10 SP - 1736-1742 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0242270882&partnerID=MN8TOARS KW - dispersive channels KW - indoor radio communication KW - multimode waveguides KW - wireless local-area network (LAN) ER - TY - JOUR TI - Imaging of optical field confinement in ridge waveguides fabricated on very-small-aperture laser AU - Chen, F. AU - Itagi, A. AU - Bain, J.A. AU - Stancil, D.D. AU - Schlesinger, T.E. AU - Stebounova, L. AU - Walker, G.C. AU - Akhremitchev, B.B. T2 - Applied Physics Letters AB - Optical field confinement in a ridge waveguide nanostructure (“C” aperture) designed for ultrahigh-density recording was observed using an apertureless near-field scanning optical microscope. The aperture was fabricated on a commercial edge-emitting semiconductor laser as the light source. High-contrast near-field images at both 1× and 2× lock-in detection frequencies were obtained. The emission patterns are in agreement with theoretical simulation of such structures. A 90 nm×70 nm full width half maximum spot size was measured and is comparable to the ridge width of the aperture. DA - 2003/// PY - 2003/// DO - 10.1063/1.1621088 VL - 83 IS - 16 SP - 3245-3247 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0242413207&partnerID=MN8TOARS ER - TY - JOUR TI - Experimental effects of laser power on the writability and pulse width in a heat assisted longitudinal recording system AU - Rausch, T. AU - Bain, J.A. AU - Stancil, D.D. AU - Schlesinger, T.E. AU - Challener, W.A. AU - McDaniel, T. AU - Deeman, N. AU - Brucker, C. T2 - Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers DA - 2003/// PY - 2003/// VL - 42 IS - 2 B SP - 989-994 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0038325743&partnerID=MN8TOARS ER - TY - CONF TI - Efficiency of light coupling from a light delivery system to a planar waveguide for optical and hybrid recording heads AU - Itagi, A.V. AU - Schlesinger, T.E. AU - Bain, J.A. AU - Stancil, D.D. AB - The efficiency of end-fire coupling between a light delivery system and a planar waveguide for optical/hybrid recording heads is calculated using a mode-matching technique. C2 - 2003/// C3 - Proceedings of SPIE - The International Society for Optical Engineering DA - 2003/// DO - 10.1117/12.533126 VL - 5069 SP - 341-344 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0242467763&partnerID=MN8TOARS KW - optical recording KW - hybrid recording KW - waveguide KW - end-fire coupling KW - mode matching ER - TY - JOUR TI - Domain position detection magnetic amplifying magneto-optical system (MAMMOS) AU - Herget, P. AU - Schlesinger, T.E. AU - Stancil, D.D. T2 - Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers DA - 2003/// PY - 2003/// VL - 42 IS - 2 B SP - 1080-1081 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0038059394&partnerID=MN8TOARS ER - TY - JOUR TI - Aperture shape effect on the performance of very small aperture lasers AU - Chen, F. AU - Stancil, D.D. AU - Schlesinger, T.E. T2 - Journal of Applied Physics AB - We report on the effect of different aperture shapes on the power output of a very small aperture laser (VSAL) fabricated from commercial edge-emitting laser diodes and correlate the results to the layer structure and polarization of the optical field. A waveguide theory is used to explain the experimental observations. We show that the shape of the aperture has a significant effect on the VSAL output power. In particular shapes exploiting the asymmetry of the laser can achieve much higher throughput over square apertures while keeping the aperture area constant. This work also indicates the validity of analyzing near-field small apertures as cutoff waveguide structures. DA - 2003/// PY - 2003/// DO - 10.1063/1.1568150 VL - 93 IS - 10 1 SP - 5871-5874 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0037636605&partnerID=MN8TOARS ER - TY - CONF TI - Antennas in a waveguide propagation environment AU - Nikitin, P.V. AU - Stancil, D.D. AU - Cepni, A.G. AU - Xhafa, A.E. AU - Tonguz, O.K. AU - Areklett, K. AU - Brodtkorb, D. C2 - 2003/// C3 - IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) DA - 2003/// VL - 2 SP - 1181-1184 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0042972878&partnerID=MN8TOARS ER - TY - JOUR TI - A novel mode content analysis technique for antennas in multimode waveguides AU - Nikitin, P.V. AU - Stancil, D.D. AU - Cepni, A.G. AU - Xhafa, A.E. AU - Tonguz, O.K. AU - Brodtkorb, D. T2 - IEEE Transactions on Microwave Theory and Techniques AB - This paper presents a novel technique for analyzing the mode content excited by antennas placed in multimode waveguides. The technique is based on measuring the frequency response between the two antennas coupled into a waveguide and using that information to extract the mode content generated by the transmitting antenna. The technique is applicable to cases in which the mode amplitudes are approximately constant over the frequency range of interest. This method is valuable for determining the mode mix generated by arbitrary transmitting antennas in a multimode waveguide propagation environment. An example of such an environment is heating, ventilation, and air-conditioning (HVAC) ducts used for indoor communications, where an important antenna characteristic is the mode sensitivity (analogous to the antenna directive gain in free space). We validate our technique with the example of a monopole probe antenna coupled into a multimode cylindrical HVAC duct. DA - 2003/// PY - 2003/// DO - 10.1109/TMTT.2003.820171 VL - 51 IS - 12 SP - 2402-2408 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0742269425&partnerID=MN8TOARS KW - antennas KW - indoor radio communication KW - microwave measurements KW - multimode waveguides ER - TY - CONF TI - A Study of Near-field Aperture Geometry Effects on Very Small Aperture Lasers (VSAL) AU - Chen, F. AU - Itagi, A. AU - Stebounova, L. AU - Bain, J.A. AU - Stancil, D.D. AU - Walker, G.C. AU - Schlesinger, T.E. AB - We have investigated nano-apertures with different geometries on VSALs using far-field measurements, near-field measurements, and finite difference time domain (FDTD) simulation methods. We were able to quantitatively verify the aperture geometry dependent power throughput in all three methods. From both far-field measurements and FDTD simulation results, we conclude that for the apertures of the same area, a rectangular aperture with the long side perpendicular to the active layer has the largest throughput, while a circular aperture has the second largest, and the rectangular aperture with the long side parallel to the active layer has the least throughput among the three. We have attempted to correlate the relationship between far-field power and near-field power. Employing an apertureless near-field scanning optical microscopy (NSOM), we found that for the two rectangular apertures being studied, the near-field power throughput results was consistent to that of far-field measurement. Using VSALs as a near-field aperture testbed was also proposed and demonstrated. C2 - 2003/// C3 - Proceedings of SPIE - The International Society for Optical Engineering DA - 2003/// DO - 10.1117/12.532753 VL - 5069 SP - 312-318 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0242443352&partnerID=MN8TOARS KW - very small aperture laser (VSAL) KW - nano-aperture KW - aperture geometry KW - power throughput KW - far-field KW - near-field KW - apertureless NSOM KW - finite difference time domain (FDTD) KW - focused ion beam (FIB) ER - TY - PAT TI - Solventless, resistless direct dielectric patterning AU - Gleason, K. K. AU - Ober, C. AU - Herr, D. C2 - 2003/// DA - 2003/// PY - 2003/// ER - TY - PAT TI - Telephone number recognition of spoken telephone number in a voice message stored in a voice messaging system AU - Kermani, B. G. C2 - 2003/// DA - 2003/// PY - 2003/// ER - TY - PAT TI - Partial voice message deletion AU - Kermani, B. G. C2 - 2003/// DA - 2003/// PY - 2003/// ER - TY - PAT TI - Magnetic mouse and/or mouse-pad AU - Kermani, B. G. AU - Dayal, S. C2 - 2003/// DA - 2003/// PY - 2003/// ER - TY - PAT TI - Integration of monocrystalline oxide devices with fully depleted CMOS on non-silicon substrates AU - Croswell, R. AU - Dunn, G. C2 - 2003/// DA - 2003/// PY - 2003/// ER - TY - PAT TI - Semiconductor structures with trench contacts AU - Huang, Q. C2 - 2003/// DA - 2003/// PY - 2003/// ER - TY - CONF TI - Outcomes based curriculum development in a new and emerging biomedical engineering program AU - McCord, M. G. AU - Blanchard, S. M. AU - Mente, P. L. AU - Nagle, H. T. AU - Spurlin, J. E. C2 - 2003/// C3 - American Society for Engineering Education DA - 2003/// ER - TY - CONF TI - Assessment of introduction to engineering and problem-solving course AU - Spurlin, J. E. AU - Lavelle, J. AU - Robbins, M. C. AU - Rajala, S. A. C2 - 2003/// C3 - American Society for Engineering Education DA - 2003/// ER - TY - CONF TI - Virtual Simple Architecture (VISA): Exceeding the complexity limit in safe real-time systems AU - Anantaraman, A. AU - Seth, K. AU - Patil, K. AU - Rotenberg, E. AU - F. Mueller, F. C2 - 2003/// C3 - Computers and their applications :|bproceedings of the ISCA 16th International Conference, Seattle, Washington, USA, March 28-30, 2001 DA - 2003/// SP - 350-361 PB - Cary, NC: ISCA SN - 1880843374 ER - TY - JOUR TI - Slipstream execution mode for CMP-based multiprocessors AU - Ibrahim, KZ AU - Byrd, GT AU - Rotenberg, E T2 - NINTH INTERNATIONAL SYMPOSIUM ON HIGH-PERFORMANCE COMPUTER ARCHITECTURE, PROCEEDINGS AB - Scalability of applications on distributed shared-memory (DSM) multiprocessors is limited by communication overheads. At some point, using more processors to increase parallelism yields diminishing returns or even degrades performance. When increasing concurrency is futile, we propose an additional mode of execution, called slipstream mode, that instead enlists extra processors to assist parallel tasks by reducing perceived overheads. We consider DSM multiprocessors built from dual-processor chip multiprocessor (CMP) nodes with shared L2 cache. A task is allocated on one processor of each CMP node. The other processor of each node executes a reduced version of the same task. The reduced version skips shared-memory stores and synchronization, running ahead of the true task. Even with the skipped operations, the reduced task makes accurate forward progress and generates an accurate reference stream, because branches and addresses depend primarily on private data. Slipstream execution mode yields two benefits. First, the reduced task prefetches data on behalf of the true task. Second, reduced tasks provide a detailed picture of future reference behavior, enabling a number of optimizations aimed at accelerating coherence events, e.g., self-invalidation. For multiprocessor systems with up to 16 CMP nodes, slipstream mode outperforms running one or two conventional tasks per CMP in 7 out of 9 parallel scientific benchmarks. Slipstream mode is 12-19% faster with prefetching only and up to 29% faster with self-invalidation enabled. DA - 2003/// PY - 2003/// DO - 10.1109/hpca.2003.1183536 VL - 12 SP - 179-190 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84955465003&partnerID=MN8TOARS ER - TY - JOUR TI - FAST: Frequency-aware static timing analysis AU - Seth, K AU - Anantaraman, A AU - Mueller, F AU - Rotenberg, E T2 - RTSS 2003: 24TH IEEE INTERNATIONAL REAL-TIME SYSTEMS SYMPOSIUM, PROCEEDINGS AB - Power is a valuable resource in embedded systems as the lifetime of many such systems is constrained by their battery capacity. Recent advances in processor design have added support for dynamic frequency/voltage scaling (DVS) for saving power. Recent work on real-time scheduling focuses on saving power in static as well as dynamic scheduling environments by exploiting idle and slack due to early task completion for DVS of subsequent tasks. These scheduling algorithms rely on a priori knowledge of worst-case execution times (WCET) for each task. They assume that DVS has no effect on the worst-case execution cycles (WCEC) of a task and scale the WCET according to the processor frequency. However, for systems with memory hierarchies, the WCEC typically does not change under DVS due to frequency modulation. Hence, current assumptions used by DVS schemes result in a highly exaggerated WCET. This paper contributes novel techniques for tight and flexible static timing analysis particularly well-suited for dynamic scheduling schemes. The technical contributions are as follows: (1) we assess the problem of changing execution cycles due to scaling techniques. (2) We propose a parametric approach towards bounding the WCET statically with respect to the frequency. Using a parametric model, we can capture the effect of changes in frequency on the WCEC and thus, accurately model the WCET over any frequency range. (3) We discuss design and implementation of the frequency-aware static timing analysis (FAST) tool based on our prior experience with static timing analysis. (4) We demonstrate in experiments that our FAST tool provides safe upper bounds on the WCET, which are tight. The FAST tool allows us to capture the WCET of six benchmarks using equations that overestimate the WCET by less than 1%. FAST equations can also be used to improve existing DVS scheduling schemes to ensure that the effect of frequency scaling on WCET is considered and that the WCET used is not exaggerated. (5) We leverage three DVS scheduling schemes by incorporating FAST into them and by showing that the power consumption further decreases. To the best of our knowledge, this study of DVS effects on timing analysis is unprecedented. DA - 2003/// PY - 2003/// DO - 10.1109/real.2003.1253252 SP - 40-51 ER - TY - JOUR TI - Adaptive mode control: A static-power-efficient cache design AU - Huiyang AU - Toburen, M. C. AU - Rotenberg, E. AU - Conte, T. M. T2 - ACM Transactions on Embedded Computing Systems AB - Lower threshold voltages in deep submicron technologies cause more leakage current, increasing static power dissipation. This trend, combined with the trend of larger/more cache memories dominating die area, has prompted circuit designers to develop SRAM cells with low-leakage operating modes (e.g., sleep mode). Sleep mode reduces static power dissipation, but data stored in a sleeping cell is unreliable or lost. So, at the architecture level, there is interest in exploiting sleep mode to reduce static power dissipation while maintaining high performance.Current approaches dynamically control the operating mode of large groups of cache lines or even individual cache lines. However, the performance monitoring mechanism that controls the percentage of sleep-mode lines, and identifies particular lines for sleep mode, is somewhat arbitrary. There is no way to know what the performance could be with all cache lines active, so arbitrary miss rate targets are set (perhaps on a per-benchmark basis using profile information), and the control mechanism tracks these targets. We propose applying sleep mode only to the data store and not the tag store. By keeping the entire tag store active the hardware knows what the hypothetical miss rate would be if all data lines were active, and the actual miss rate can be made to precisely track it. Simulations show that an average of 73% of I-cache lines and 54% of D-cache lines are put in sleep mode with an average IPC impact of only 1.7%, for 64 KB caches. DA - 2003/// PY - 2003/// DO - 10.1145/860176.860181 VL - 2 IS - 3 SP - 347–372 ER - TY - JOUR TI - Special Issue on the First IEEE Conference on Sensors (Sensors 2002) - Part II AU - Nagle, HT T2 - IEEE SENSORS JOURNAL DA - 2003/12// PY - 2003/12// DO - 10.1109/JSEN.2003.820660 VL - 3 IS - 6 SP - 677-677 SN - 1530-437X ER - TY - CHAP TI - Geodesic object representation and recognition AU - Ben Hamza, A. AU - Krim, H. T2 - Discrete geometry for computer imagery: 11th International Conference, DGCI 2003, Naples, Italy, November 19-21, 2003 A2 - B. Hamza, A2 - Krim, H. AB - This paper describes a shape signature that captures the intrinsic geometric structure of 3D objects. The primary motivation of the proposed approach is to encode a 3D shape into a one-dimensional geodesic distribution function. This compact and computationally simple representation is based on a global geodesic distance defined on the object surface, and takes the form of a kernel density estimate. To gain further insight into the geodesic shape distribution and its practicality in 3D computer imagery, some numerical experiments are provided to demonstrate the potential and the much improved performance of the proposed methodology in 3D object matching. This is carried out using an information-theoretic measure of dissimilarity between probabilistic shape distributions. CN - T385 .D525 2003 PY - 2003/// DO - 10.1007/978-3-540-39966-7_36 VL - 2886 SP - 378-387 PB - Berlin; New York: Springer SN - 3540204997 ER - TY - JOUR TI - Total delay compensation in LAN control systems and implications for scheduling AU - Bauer, PH AU - Lorand, C AU - Sichitiu, M AU - Premaratne, K T2 - INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE AB - The first part of this paper shows that long access delays are not necessarily detrimental to the stability of local area network embedded control systems. The second part shows that (under some mild conditions on the control system) scheduling in the return path is not needed. This is a consequence of the fact that for local area networks the access delays can be exactly determined and completely eliminated from the system representation. DA - 2003/// PY - 2003/// DO - 10.1080/00207720310001614862 VL - 34 IS - 10-11 SP - 599-605 SN - 1464-5319 ER - TY - JOUR TI - Riparian Ecosystem Management Model: Hydrology performance and sensitivity in the North Carolina Middle Coastal Plain AU - Dukes, M. D. AU - Evans, R. O. T2 - Transactions of the ASAE AB - A riparian buffer installed along streams is one alternative that can be used to reduce the delivery of nitrogen,phosphorus, and sediment to the stream. The Riparian Ecosystem Management Model (REMM) has been developed tosimulate surface and subsurface riparian buffer hydrology, sediment transport, litter and sediment interactions, vegetationgrowth, and soil carbon, nitrogen, and phosphorus dynamics. For this model to accurately simulate transport and fate ofnutrients in the shallow groundwater beneath a riparian buffer, the subsurface hydrology component must be verified. Twoyears of field data were utilized to evaluate and test the sensitivity of the hydrology component of REMM in the North CarolinaMiddle Coastal Plain. Daily simulated water table depth was compared to observed water table depths across a 15 m widebuffer. The simulated water table depth was sensitive to hydrologic parameters such as groundwater inputs from the uplandinto zone 3, stream depth, and buffer slope. Average absolute errors between simulated and observed water table depth werefound to be 0.35 to 0.36 m, while relative errors ranged from 0.12 to 0.15 m. Simulated evapotranspiration (ET) was higherin zone 3 compared to zones 1 and 2, although all three zones were parameterized alike. Flow into the buffer from the streamis not simulated by REMM, although it occurred frequently during data collection. Estimates of ET should be improved forherbaceous and grass vegetation types to improve water table depth predictions. Also, for conditions where the streamcontributes flow to the groundwater, an additional component in REMM is necessary. DA - 2003/// PY - 2003/// DO - 10.13031/2013.15645 VL - 46 IS - 6 SP - 1567-1579 ER - TY - JOUR TI - Efficient nitride-based short-wavelength emitters with enhanced hole injection AU - Zavada, J. M. AU - Komirenko, S. M. AU - Kim, K. W. AU - Kochelap, V. A. T2 - Compound Semiconductors 2002 DA - 2003/// PY - 2003/// VL - 174 IS - 2003 SP - 401-404 ER - TY - JOUR TI - Wavelength-dependent Raman scattering of hydrogenated amorphous silicon carbon with red, green, and blue light excitation AU - Park, M AU - Sakhrani, V AU - Maria, JP AU - Cuomo, JJ AU - Teng, CW AU - Muth, JF AU - Ware, ME AU - Rodriguez, BJ AU - Nemanich, RJ T2 - JOURNAL OF MATERIALS RESEARCH AB - This study presents results of wavelength-dependent Raman scattering from amorphous silicon carbon (a-Si:C:H). The a-Si:C:H films were produced by radio-frequency plasma-enhanced chemical vapor deposition. Prior results with amorphous carbon indicate that laser excitation selectively probes clusters with differing sizes. Our measurements with a-Si:C:H indicate that when using red (632.8 nm), green (514.5 nm), and blue (488.0 nm) excitation, the Raman D and G peaks shift to higher wave numbers as the excitation energy increases. The higher frequency is associated with smaller clusters that are preferentially excited with higher photon energy. It appears that photoluminescence occurs due to radiative recombination from intracluster transitions in Si-alloyed sp 2 -bonded carbon clusters DA - 2003/4// PY - 2003/4// DO - 10.1557/JMR.2003.0106 VL - 18 IS - 4 SP - 768-771 SN - 2044-5326 ER - TY - JOUR TI - The first fluorescent sensor for D-glucarate based on the cooperative action of boronic acid and guanidinium groups AU - Yang, WQ AU - Yan, J AU - Fang, H AU - Wang, BH T2 - CHEMICAL COMMUNICATIONS AB - A new fluorescent sensor (1) with a recognition unit consisting of a boronic acid moiety and a guanidinium unit shows selective binding of D-glucarate in aqueous solution. DA - 2003/// PY - 2003/// DO - 10.1039/b300098b IS - 6 SP - 792-793 SN - 1364-548X ER - TY - JOUR TI - Origin of intrinsic oscillations in double-barrier quantum-well systems AU - Zhao, PJ AU - Woolard, DL AU - Cui, HL AU - Horing, NJM T2 - PHYSICS LETTERS A AB - We present a theory accounting for the origin of high-frequency current oscillations in a double barrier quantum-well system. The origin of such current oscillations is traced to the development of a dynamic emitter quantum-well and the concomitant coupling of the energy levels in the double barrier quantum-well system. The relationship between the oscillation frequency and the energy level structure of the system is expressed as ν=ΔE0/h: A self-consistent, time-dependent Wigner–Poisson numerical computer experiment is used to exhibit remarkable intrinsic, sustained current oscillations in the double-barrier quantum well at terahertz frequencies; and a procedure for calculating ΔE0, the energy difference at time t0 (defined such that the contribution to the energy difference from the potential oscillation is zero) is also presented. The simulated oscillation frequency determined using the Wigner–Poisson analysis is in very good agreement with that calculated using a Schrödinger equation with a self-consistent potential determined from the Poisson equation. DA - 2003/5/19/ PY - 2003/5/19/ DO - 10.1016/S0375-9601(03)00543-7 VL - 311 IS - 4-5 SP - 432-437 SN - 1873-2429 KW - intrinsic oscillation KW - resonant tunneling KW - quantum transport ER - TY - JOUR TI - Optical and structural studies of hydride vapor phase epitaxy grown GaN AU - Chang, YC AU - Cai, AL AU - Muth, JF AU - Kolbas, RM AU - Park, M AU - Cuomo, JJ AU - Hanser, A AU - Bumgarner, J T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - Thick films of hydride vapor phase epitaxy (HVPE) grown GaN were studied by various techniques. Time-integrated and time-resolved photoluminescence (PL) measurements were performed at room temperature and 77 K. The time-integrated PL spectrum has no observed deep-level transitions and a very narrow linewidth, which indicates good material quality. Time-resolved PL spectra are also presented and the temporal evolution of the PL around the band-gap exhibits a biexponential decay with a fast and a slow decay component. Cathodoluminescence, x-ray, and Raman spectroscopy were also used. The full width half maximum of the x-ray rocking curve for our sample is approximately 375 arcsec. The polarized Raman spectra exhibited only the allowed modes. The deposited GaN films were found to be relatively stress free. The x ray and Raman analysis also revealed that the HVPE-grown GaN films are of high crystal quality. The effect of thermal annealing on the sample was also investigated by time-integrated and time-resolved PL and Raman spectroscopy. No significant changes in the material were observed in either time-integrated or Raman spectroscopy. The film was thermally stable upon annealing up to 1000 °C in N2 ambient based on the results of these measurements. In time-resolve photoluminescence measurement, the temporal evolution of the band-edge transitions broadens after each annealing step and is significantly different after the 1000 °C anneal. DA - 2003/// PY - 2003/// DO - 10.1116/1.1568346 VL - 21 IS - 3 SP - 701-705 SN - 0734-2101 ER - TY - JOUR TI - Extension and validation of a perfectly matched layer formulation for the unconditionally stable D-H FDTD method AU - Schmidt, S AU - Lazzi, G T2 - IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS AB - In this letter, a modification to the recently proposed unconditionally stable D-H ADI FDTD method is presented that considerably reduces the late-time error induced by the corner cells. The PML boundary is derived from the direct discretization of the modified D-H Maxwell's equations rather than the superposition of uniaxial PML boundaries. An optimal choice of the PML conductivity profile coefficients is proposed. Results show that the reflection error of the PML is limited for increased time step size beyond the Courant-Friedrichs-Lewy stability bound, and maximum reflection errors are 15 to 20 dB lower than the original formulation. DA - 2003/8// PY - 2003/8// DO - 10.1109/LMWC.2003.815693 VL - 13 IS - 8 SP - 345-347 SN - 1558-1764 KW - ADI KW - FDTD methods KW - PML ABC ER - TY - JOUR TI - Electron spin relaxation under drift in GaAs AU - Barry, E. A. AU - Kiselev, A. A. AU - Kim, K. W. T2 - Applied Physics Letters AB - Based on a Monte Carlo method, we investigate the influence of transport conditions on the electron spin relaxation in GaAs. The decay of initial electron spin polarization is calculated as a function of distance under the presence of moderate drift fields and/or nonzero injection energies. For relatively low fields (a couple of kV/cm), a substantial amount of spin polarization is preserved for several microns at 300 K. However, it is also found that the spin relaxation rate increases rapidly with the drift field, scaling as the square of the electron wave vector in the direction of the field. When the electrons are injected with a high energy, a pronounced decrease is observed in the spin relaxation length due to an initial increase in the spin precession frequency. Hence, high-field or high-energy transport conditions may not be desirable for spin-based devices. DA - 2003/5/26/ PY - 2003/5/26/ DO - 10.1063/1.1578180 VL - 82 IS - 21 SP - 3686-3688 J2 - Appl. Phys. Lett. LA - en OP - SN - 0003-6951 1077-3118 UR - http://dx.doi.org/10.1063/1.1578180 DB - Crossref ER - TY - JOUR TI - Two-dimensional SPICE-linked multiresolution impedance method for low-frequency electromagnetic interactions AU - Eberdt, M AU - Brown, PK AU - Lazzi, G T2 - IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING AB - A multiresolution impedance method for the solution of low-frequency electromagnetic interaction problems typically encountered in bioelectromagnetics is presented. While the impedance method in its original form is based on the discretization of the scattering objects into equal-sized cells, our formulation decreases the number of unknowns by using an automatic mesh generation method that does not yield equal-sized cells in the modeling space. Results indicate that our multiresolution mesh generation scheme can provide a 50%-80% reduction in cell count, providing new opportunities for the solution of low-frequency bioelectromagnetic problems that require a high level of detail only in specific regions of the modeling space. Furthermore, linking the mesh generator to a circuit simulator such as SPICE permits the addition of arbitrarily complex passive and active circuit elements to the generated impedance network, opening the door to significant advances in the modeling of bioelectromagnetic phenomena. DA - 2003/7// PY - 2003/7// DO - 10.1109/TBME.2003.813534 VL - 50 IS - 7 SP - 881-889 SN - 0018-9294 KW - dosimetry KW - electromagnetic modeling KW - induced fields KW - numerical modeling ER - TY - CHAP TI - Tree Traversal Scheduling: A Global Instruction Scheduling Technique for VLIW/EPIC Processors AU - Zhou, Huiyang AU - Jennings, Matthew D. AU - Conte, Thomas M. T2 - Languages and Compilers for Parallel Computing AB - Global scheduling in a treegion framework has been proposed to exploit instruction level parallelism (ILP) at compile time. A treegion is a single-entry / multiple-exit global scheduling scope that consists of basic blocks with control-flow forming a tree. Because a treegion scope is nonlinear (includes multiple paths) it is distinguished from linear scopes such as traces or superblocks. Treegion scheduling has the capability of speeding up all possible paths within the scheduling scope. This paper presents a new global scheduling algorithm using treegions called Tree Traversal Scheduling (TTS). Efficient, incremental data-flow analysis in support of TTS is also presented. Performance results are compared to the scheduling of the linear regions that result from the decomposition of treegions. We refer to these resultant linear regions as linear treegions (LT) and consider them analogous to superblocks with the same amount of code expansion as the base treegion. Experimental results for TTS scheduling show a 35% speedup compared to basic block (BB) scheduling and a 4% speedup compared to LT scheduling. PY - 2003/// DO - 10.1007/3-540-35767-x_15 VL - 2624 SP - 223-238 OP - PB - Springer Berlin Heidelberg SN - 9783540040293 9783540357674 UR - http://dx.doi.org/10.1007/3-540-35767-x_15 DB - Crossref ER - TY - JOUR TI - The effect of uncertain time-variant delays in ATM networks with explicit rate feedback: A control theoretic approach AU - Sichitiu, ML AU - Bauer, PH AU - Premaratne, K T2 - IEEE-ACM TRANSACTIONS ON NETWORKING AB - A new, more realistic model for the available bit rate traffic class in ATM network congestion control with explicit rate feedback is introduced and analyzed. This model is based on recent results by M.M. Ekanayake ("Robust stability of discrete time nonlinear systems", Ph.D. dissertation, Univ. Miami, Coral Gables, FL, 1999) regarding discrete time models for time-variant delays. The discrete time model takes into account the effect of time-variant buffer occupancy levels of ATM switches, thus treating the case of time-variant delays between a single congested node and the connected sources. For highly dynamic situations, such a model is crucial for a valid analysis of the resulting feedback system. The new model also handles the effects of the mismatch between the resource management cell rates and the variable bit rate controller sampling rate as well as buffer and rate nonlinearities. A brief stability study shows that an equilibrium in the buffer occupancy is impossible to achieve in the presence of time-variant forward path delays. Stability conditions for the case of time-variant delays in the return path are presented. Finally, illustrative examples are provided. DA - 2003/8// PY - 2003/8// DO - 10.1109/TNET.2003.815293 VL - 11 IS - 4 SP - 628-637 SN - 1558-2566 ER - TY - PAT TI - Supermolecular structures and devices made from same AU - Herr, D. J. C. AU - Zhirnov, V. V. C2 - 2003/// DA - 2003/// PY - 2003/// ER - TY - JOUR TI - Nonlinear regimes of coherent optical phonon generation in quantum wells under electric current pumping AU - Komirenko, S. M. AU - Kim, K. W. AU - Kochelap, V. A. AU - Koroteev, V. V. AU - Stroscio, M. A. T2 - Physical Review B AB - We present an analysis of nonlinear regimes of the coherent optical phonon generation under the electron drift in quantum wells. The phonon and electron subsystems are treated self-consistently. This allows us to find the steady-state generation regimes with macroscopic populations of optical phonon modes and the electron transport controlled in part by the generated phonons. The generation regimes demonstrate a pronounced threshold character. At high electric fields above the threshold, practically single-mode generation occurs and the current-voltage characteristic is considerably changed. We demonstrate high efficiency generation of the coherent optical phonons by the electric current. The coherent macroscopic optical displacements and the amplitudes of oscillating electrostatic fields are evaluated. The proposed model based on the electron nonlinearities predicts a range of the pumping electric fields under which the steady state phonon generation is realized. Our results suggest that the phonon avalanche occurs beyond this field range. DA - 2003/10/14/ PY - 2003/10/14/ DO - 10.1103/physrevb.68.155308 VL - 68 IS - 15 SP - J2 - Phys. Rev. B LA - en OP - SN - 0163-1829 1095-3795 UR - http://dx.doi.org/10.1103/PhysRevB.68.155308 DB - Crossref ER - TY - PAT TI - Methods of fabricating vertical field effect transistors by conformal channel layer deposition on sidewalls AU - Zhang, Z. C2 - 2003/// DA - 2003/// PY - 2003/// ER - TY - PAT TI - Method for making optoelectronic and microelectronic devices including cubic ZnMgO and/or CdMgO alloys AU - Narayan, J. AU - Sharma, A. K. AU - Muth, J. F. C2 - 2003/// DA - 2003/// PY - 2003/// ER - TY - CHAP TI - Image registration and segmentation by maximizing the Jensen-Renyi divergence AU - Ben Hamza, A. AU - Krim, H. T2 - Energy minimization methods in computer vision and pattern recognition A2 - A. Rangarajan, M. Figueiredo A2 - Zerubia, J. AB - Information theoretic measures provide quantitative entropic divergences between two probability distributions or data sets. In this paper, we analyze the theoretical properties of the Jensen-Rényi divergence which is defined between any arbitrary number of probability distributions. Using the theory of majorization, we derive its maximum value, and also some performance upper bounds in terms of the Bayes risk and the asymptotic error of the nearest neighbor classifier. To gain further insight into the robustness and the application of the Jensen-Rényi divergence measure in imaging, we provide substantial numerical experiments to show the power of this entopic measure in image registration and segmentation. CN - TA1634 .E53 2003 PY - 2003/// DO - 10.1007/978-3-540-45063-4_10 VL - 2683 SP - 147-163 PB - Berlin; New York: Springer SN - 3540404988 ER - TY - JOUR TI - Electronic visual prosthesis AU - Liu, WT AU - Sivaprakasam, M AU - Singh, PR AU - Bashirullah, RS AU - Wang, GX T2 - ARTIFICIAL ORGANS AB - Retinitis pigmentosa (RP) and age-related macular degeneration (AMD) are incurable diseases that result in profound vision loss due to degeneration of the light sensing photoreceptors. However, the discovery that direct electrical stimulation of the retinal neurons creates visual sensation has inspired prosthetic devices aimed to restore useful vision in RP/AMD patients. The approach to one such electronic visual prosthesis is described in this article. The prosthesis consists of an external unit and an internal unit. The communication link has three components--power and data transfer from the external to the internal unit, and data transfer from the internal to the external unit. A novel method of integrating power transfer and back telemetry is described here. The goal is to design a stimulator chip with a small area with low power consumption. This chip, capable of stimulating 60 dedicated electrodes, is fabricated using AMI 1.2 microm process technology and the results are presented. Improvements in the design to increase the number of outputs to 1,000 have been discussed. The new circuit is aimed at increasing the circuit density, reducing power per stimulus, and meeting the requirements more closely than the previous designs. The results of the designed chip are presented. DA - 2003/11// PY - 2003/11// DO - 10.1046/j.1525-1594.2003.07306.x VL - 27 IS - 11 SP - 986-995 SN - 1525-1594 KW - retinal prosthesis KW - telemetry KW - neurostimulator KW - inductive link KW - low power design ER - TY - JOUR TI - Design and implementation of Acceptance Monitor for building intrusion tolerant systems AU - Wang, R AU - Wang, FY AU - Byrd, GT T2 - SOFTWARE-PRACTICE & EXPERIENCE AB - Abstract Intrusion detection research has so far concentrated on techniques that effectively identify the malicious behaviors. No assurance can be assumed once the system is compromised. Intrusion tolerance, however, focuses on providing minimal level of services, even when some components have been partially compromised. The challenges here are how to take advantage of fault tolerant techniques in the intrusion tolerant system context and how to deal with possible unknown attacks and compromised components so as to continue providing the service. This paper presents our work on applying one important fault tolerance technique, acceptance testing, for building scalable intrusion tolerant systems. First, we propose a general methodology for designing acceptance testing. An Acceptance Monitor architecture is proposed to apply various tests for detecting the compromises based on the impact of the attacks. Second, we make a comprehensive vulnerability analysis on typical commercial‐off‐the‐shelf (COTS) Web servers. Various acceptance testing modules are implemented to show the effectiveness of the proposed approach. By utilizing the fault tolerance techniques on intrusion tolerance system, we provide a mechanism for building reliable distributed services that are more resistant to both known and unknown attacks. Copyright © 2003 John Wiley & Sons, Ltd. DA - 2003/11/25/ PY - 2003/11/25/ DO - 10.1002/spe.554 VL - 33 IS - 14 SP - 1399-1417 SN - 0038-0644 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0242408350&partnerID=MN8TOARS KW - fault tolerance KW - intrusion tolerance KW - acceptance testing ER - TY - JOUR TI - Delay-based congestion avoidance for TCP AU - Martin, J AU - Nilsson, A AU - Rhee, I T2 - IEEE-ACM TRANSACTIONS ON NETWORKING AB - The set of TCP congestion control algorithms associated with TCP-Reno (e.g., slow-start and congestion avoidance) have been crucial to ensuring the stability of the Internet. Algorithms such as TCP-NewReno (which has been deployed) and TCP-Vegas (which has not been deployed) represent incrementally deployable enhancements to TCP as they have been shown to improve a TCP connection's throughput without degrading performance to competing flows. Our research focuses on delay-based congestion avoidance algorithms (DCA), like TCP-Vegas, which attempt to utilize the congestion information contained in packet round-trip time (RTT) samples. Through measurement and simulation, we show evidence suggesting that a single deployment of DCA (i.e., a TCP connection enhanced with a DCA algorithm) is not a viable enhancement to TCP over high-speed paths. We define several performance metrics that quantify the level of correlation between packet loss and RTT. Based on our measurement analysis, we find that, although there is useful congestion information contained within RTT samples, the level of correlation between an increase in RTT and packet loss is not strong enough to allow a TCP-sender to improve throughput reliably. While DCA is able to reduce the packet loss rate experienced by a connection, in its attempts to avoid packet loss, the algorithm reacts unnecessarily to RTT variation that is not associated with packet loss. The result is degraded throughput as compared to a similar flow that does not support DCA. DA - 2003/6// PY - 2003/6// DO - 10.1109/TNET.2003.813038 VL - 11 IS - 3 SP - 356-369 SN - 1558-2566 KW - TCP congestion control KW - delay-based congestion avoidance (DCA) KW - TCP/Vegas KW - loss and round-trip time (RTT) correlation patterns ER - TY - JOUR TI - Correlation prefetching with a user-level memory thread AU - Solihin, Y. AU - Lee, J. AU - Torrellas, J. T2 - IEEE Transactions on Parallel and Distributed Systems AB - This paper proposes using a user-level memory thread (ULMT) for correlation prefetching. In this approach, a user thread runs on a general-purpose processor in main memory, either in the memory controller chip or in a DRAM chip. The thread performs correlation prefetching in software, sending the prefetched data into the L2 cache of the main processor. This approach requires minimal hardware beyond the memory processor: The correlation table is a software data structure that resides in main memory, while the main processor only needs a few modifications to its L2 cache so that it can accept incoming prefetches. In addition, the approach has wide applicability, as it can effectively prefetch even for irregular applications. Finally, it is very flexible, as the prefetching algorithm can be customized by the user on an application basis. Our simulation results show that, through a new design of the correlation table and prefetching algorithm, our scheme delivers good results. Specifically, nine mostly-irregular applications show an average speedup of 1.32. Furthermore, our scheme works well in combination with a conventional processor-side sequential prefetcher, in which case the average speedup increases to 1.46. Finally, by exploiting the customization of the prefetching algorithm, we increase the average speedup to 1.53. DA - 2003/// PY - 2003/// DO - 10.1109/tpds.2003.1206504 VL - 14 IS - 6 SP - 563-580 ER - TY - JOUR TI - Computational leakage: Grover's algorithm with imperfections AU - Song, P. H. AU - Kim, I. T2 - European Physical Journal. D, Atomic, Molecular and Optical Physics DA - 2003/// PY - 2003/// VL - 23 IS - 2 SP - 299-303 ER - TY - JOUR TI - Agile software development: It's about feedback and change AU - Williams, L AU - Cockburn, A T2 - COMPUTER AB - Currently, the focus is on determining how to blend agile methodologies with plan-driven approaches to software development. DA - 2003/6// PY - 2003/6// DO - 10.1109/MC.2003.1204373 VL - 36 IS - 6 SP - 39-43 SN - 1558-0814 ER - TY - JOUR TI - Thermal stability of TaSixNy films deposited by reactive sputtering on SiO2 AU - Suh, YS AU - Heuss, GP AU - Misra, V AU - Park, DG AU - Limb, KY T2 - JOURNAL OF THE ELECTROCHEMICAL SOCIETY AB - The thermal stability of /p-type Si metal-insulator-semiconductor structure has been evaluated by measuring equivalent oxide thickness (EOT) from capacitance-voltage curves and gate leakage current as a function of annealing temperatures. films were deposited using reactive sputtering from a target, varying the nitrogen/argon flow ratio. A reaction between and was observed after a 1000°C anneal, resulting in the increase of interfacial roughness and oxide thickness in the structures. Cross-sectional transmission electron microscopy shows no indication of an interfacial reaction or crystallization in on up to 1000°C as manifested by the negligible change in EOT and the stable leakage currents density A/cm2 at V). The presence of Si-N bonds is attributed to cause the amorphous nature of the high N-containing films. This may retard the formation of an interface layer and improve the chemical-thermal stability of the gate electrode/dielectric interface and oxygen diffusion barrier properties under high-temperature annealing. © 2003 The Electrochemical Society. All rights reserved. DA - 2003/5// PY - 2003/5// DO - 10.1149/1.1562599 VL - 150 IS - 5 SP - F79-F82 SN - 1945-7111 ER - TY - JOUR TI - Streaming distribution of two-dimensional electrons in III-N heterostructures for electrically pumped terahertz generation AU - Korotyeyev, V. V. AU - Kochelap, V. A. AU - Kim, K. W. AU - Woolard, D. L. T2 - Applied Physics Letters AB - We studied anisotropic electron distributions in group-III-nitride quantum wells and analyzed formation of the streaming regime under moderate electric fields. We found that the streaming effect can occur in high-mobility heterostructures (μ⩾30 000 cm2/V s) with low electron concentrations (n⩽1012 cm−2) at temperatures above 77 K. The effect holds in the electric fields of a few kV/cm. These conditions can be met in contemporary high-quality nitride heterostructures that have advantages over the bulk materials due to the specifics of electron–phonon and electron–electron interactions in two-dimensional structures. Subsequently, the streaming effect may enable the development of electrically-pumped THz sources operating above the nitrogen temperature based on nitride heterostructures. DA - 2003/4/21/ PY - 2003/4/21/ DO - 10.1063/1.1569039 VL - 82 IS - 16 SP - 2643-2645 J2 - Appl. Phys. Lett. LA - en OP - SN - 0003-6951 1077-3118 UR - http://dx.doi.org/10.1063/1.1569039 DB - Crossref ER - TY - JOUR TI - Reconstructing discontinuous surfaces from a given gradient field using partial integrability AU - Karacali, B AU - Snyder, W T2 - COMPUTER VISION AND IMAGE UNDERSTANDING AB - This paper describes an adaptive surface reconstruction method from a given gradient field that allows discontinuities in the solution. We first formalize a vector space projection technique to reconstruct a surface with a uniformly integrable gradient field that corresponds to the minimum norm solution in the gradient space over discrete imaging settings. Next, we generalize this technique to reconstruct minimum norm solution surfaces with partially integrable gradient fields, where partial integrability is characterized adaptively from the given gradient field using multi-scale gradient space expansions. The simulations on synthesized and real data using block processing techniques indicate that the proposed method provides fast and reliable surface reconstruction through accurate characterization of embedded partial integrability in a given gradient field. DA - 2003/10// PY - 2003/10// DO - 10.1016/S1077-3142(03)00095-X VL - 92 IS - 1 SP - 78-111 SN - 1077-3142 KW - surface reconstruction KW - integrability KW - gradient fields KW - gradient space KW - vector space methods KW - projection KW - feasible subspace ER - TY - JOUR TI - Multisubband theory for the origination of intrinsic oscillations within double-barrier quantum well systems AU - Zhao, P. J. AU - Woolard, D. L. AU - Cui, H. L. T2 - Physical Review. B, Condensed Matter and Materials Physics DA - 2003/// PY - 2003/// VL - 67 IS - 8 SP - 085312-1 ER - TY - JOUR TI - Interactive effects of controlled drainage and riparian buffers on shallow groundwater qaulity AU - Dukes, M. D. AU - Evans, R. O. AU - Gilliam, J. W. AU - Kunickis, S. H. T2 - Journal of Irrigation and Drainage Engineering AB - As a result of recent surface water quality problems in North Carolina, riparian buffers and controlled drainage are being used to reduce the loss of nonpoint source nitrogen from agricultural fields. The effect of controlled drainage and riparian buffers as best management practices to reduce the loss of agricultural nonpoint source nitrogen from the middle coastal plain has not been well documented. The middle coastal plain is characterized by intensive agriculture on sandy soils with deeply incised or channelized streams. A 2-year study was conducted to determine the effectiveness of controlled drainage, riparian buffers, and a combination of both in the middle coastal plain of North Carolina. It was hypothesized that raising the water table near the ditch would enhance nitrate-nitrogen reduction through denitrification. On the sandy soils studied, controlled drainage did not effectively raise the water table near the ditch to a greater degree than observed on the free drainage treatment. Due to random treatment location, the free drainage treatment was installed along a ditch with a shallower impermeable layer compared to the impermeable layer on the controlled drainage treatments (2 m versus 3- to 4-m deep). This resulted in a perched or higher water table on the free drainage treatment. Over 17 storm events, the riparian buffer (free drainage) treatment had an average groundwater table depth of 0.92 m compared to 0.96 and 1.45 m for the combination (riparian buffer and controlled drainage) and controlled drainage treatments, respectively. Nitrate concentration decrease between the field wells and ditch edge wells averaged 29% (buffer only), 63% (buffer and controlled drainage), and 73% (controlled drainage only). Although apparently more nitrate was removed from the groundwater on the controlled drainage treatments, the controlled drainage treatment water table near the ditch was not raised closer to the ground surface compared to the free drainage treatment. Nitrate removal effectiveness was attributed to local soil and landscape properties, such as denitrification in deeper reduced zones of the soil profile. DA - 2003/// PY - 2003/// DO - 10.1061/(ASCE)0733-9437(2003)129:2(82) VL - 129 IS - 2 SP - 82-92 ER - TY - JOUR TI - A simulation study to evaluate the feasibility of midgap workfunction metal gates in 25 nm bulk CMOS AU - Maitra, K AU - Misra, V T2 - IEEE ELECTRON DEVICE LETTERS AB - The performance of 25 nm metallurgical channel length bulk MOSFETs with midgap workfunction metal gates has been compared with conventional polysilicon gates and bandedge workfunction metal gates. Device design using pocket halo implants was implemented to achieve the required off-state leakage specification. Highly accurate, full device simulations have been performed with a linear chain of inverters taking quantum effects into consideration. Drain induced barrier lowering (DIBL) was used as an indicator of short channel effects, and the stage delay of a linear chain of inverters and the on state drive current (I/sub on/) have been identified as metrics for performance. Compared to bandedge metal gates, midgap gates suffer from lower drive currents for both NMOS and PMOS devices. On the other hand, midgap devices were comparable in their performance to N/sup +/ polysilicon gated devices and exceeded that of P/sup +/ polysilicon devices. This high performance was attributed to a lack of poly depletion in midgap metal devices and a higher degree of DIBL which resulted in a lower V/sub t/ under high drain bias providing high drive current. Conclusions have been drawn on the feasibility of using midgap metal gates to simplify process integration in future generation CMOS devices. DA - 2003/11// PY - 2003/11// DO - 10.1109/LED.2003.819267 VL - 24 IS - 11 SP - 707-709 SN - 1558-0563 KW - bandedge KW - bulk KW - CMOS KW - DIBL KW - metal gates KW - midgap KW - NMOSFETs KW - PMOSFETs KW - simulation KW - workfunction ER - TY - JOUR TI - Special Issue on MIMO Wireless Communications AU - Blum, RS AU - Bolcskei, H AU - Fitz, MP AU - Hughes, B AU - Paulraj, AJ T2 - IEEE TRANSACTIONS ON SIGNAL PROCESSING AB - HE major challenges in future wireless communications system design are increased spectral efficiency and improved link reliability. The radio channel constitutes a hostile propagation medium, which suffers from fading (signal level fluctuations due to destructive addition of multipaths) and interference from other users. Diversity provides the receiver with several ideally independent replicas of the transmitted signal and is therefore a powerful technique to mitigate fading and interference from other users, thereby improving link reliability. The use of spatial or antenna diversity has recently become very popular since it can be provided without loss in spectral efficiency. The corresponding signal processing and coding techniques are known as space-time coding and require that multiple antennas at the transmitter and one or more antennas at the receiver are employed. The use of multiple antennas at both the transmitter and the receiver of a wireless link [multiple-input multiple-output (MIMO) technology] has recently been demonstrated, both theoretically and practically, to achieve an order of magnitude improvement in terms of spectral efficiency when compared with existing systems. MIMO wireless is evolving into one of the most active research segments in wireless communications, and the first standards based on MIMO technology are being defined. Despite the significant research efforts in the MIMO area, numerous problems related to ultimate performance limits, code design, and receiver design remain open. The present special issue is an attempt to cover a wide range of topics in MIMO wireless by publishing 26 high-quality papers reporting on recent results in the above mentioned areas. As an indication of the level of activity in this research area, there were a significant number of high-quality papers we could not include in this issue due to space constraints. The papers in this special issue correspond to advances in the understanding of six different areas of MIMO communication. The first two are analytical and include understanding the ultimate capacity that MIMO wireless links can provide as well as understanding the performance of MIMO systems. Performance and capacity are being assessed with ever increasingly sophisticated models to reflect the complex environment that MIMO communication represents. The second two relate DA - 2003/11// PY - 2003/11// DO - 10.1109/TSP.2003.818198 VL - 51 IS - 11 SP - 2709-2709 SN - 1053-587X ER - TY - JOUR TI - Molecular electronics: From devices and interconnect to circuits and architecture AU - Stan, MR AU - Franzon, PD AU - Goldstein, SC AU - Lach, JC AU - Ziegler, MM T2 - PROCEEDINGS OF THE IEEE AB - As the dominating CMOS technology is fast approaching a "brick wall," new opportunities arise for competing solutions. Nanoelectronics has achieved several breakthroughs lately and promises to overcome many of the limitations intrinsic to current semiconductor approaches. Most of the results in this area reported until now focus on devices and interconnect; this work goes several steps further and presents issues related to circuits and architecture. Based on proposed nanoscale interconnect and device structures, we explore the design space available to the nanoelectronic circuit designer and system architect. DA - 2003/11// PY - 2003/11// DO - 10.1109/JPROC.2003.818327 VL - 91 IS - 11 SP - 1940-1957 SN - 1558-2256 KW - crossbar architectures KW - defect tolerance KW - molecular electronics KW - nanocircuits KW - nanodevices KW - nanoscience KW - nanotechnology KW - nanotubes ER - TY - JOUR TI - Mathematical foundations of frequency-domain modeling of nonlinear circuits and systems using the arithmetic operator method AU - Hart, FP AU - Stephenson, DG AU - Chang, CR AU - Gharaibeh, K AU - Johnson, RG AU - Steer, MB T2 - INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING AB - The arithmetic operator method (AOM) is a method for performing arithmetic operations on one or more signals that are described by their spectra. By extension, any analytic functional operation on the signals can be performed in the frequency domain using matrix-vector operations. The mathematical foundation of AOM is presented as a numerically efficient convolution-like procedure in this article. It is directly applicable to the behavioral modeling of nonlinear RF and microwave circuits and systems. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13, 473–495, 2003. DA - 2003/11// PY - 2003/11// DO - 10.1002/mmce.10108 VL - 13 IS - 6 SP - 473-495 SN - 1096-4290 ER - TY - JOUR TI - DWf(2)Q+: a novel and efficient packet fair queuing algorithm AU - Tu, X. D. AU - Li, L. M. AU - Wang, G. X. T2 - Chinese Journal of Electronics DA - 2003/// PY - 2003/// VL - 12 IS - 2 SP - 215-218 ER - TY - JOUR TI - Current-mode signaling in deep submicrometer global interconnects AU - Bashirullah, R AU - Liu, WT AU - Cavin, RK T2 - IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS AB - This paper addresses propagation delay and power dissipation for current mode signaling in deep submicrometer global interconnects. Based on the effective lumped element resistance and capacitance approximation of distributed RC lines, simple yet accurate closed-form expressions of delay and power dissipation are presented. A new closed-form solution of delay under step input excitation is first developed, exhibiting an accuracy that is within 5% of SPICE simulations for a wide range of parameters. The usefulness of this solution is that resistive load termination for current mode signaling is accurately modeled. This model is then extended to a generalized delay formulation for ramp inputs with arbitrary rise time. Using these expressions, the optimum-line width that minimizes the total delay for current mode circuits is found. Additionally, a new power-dissipation model for current-mode signaling is developed to understand the design tradeoffs between current and voltage sensing. Based on the results and derived formulations, a comparison between voltage and current mode repeater insertion for long global deep submicrometer interconnects is presented. DA - 2003/6// PY - 2003/6// DO - 10.1109/TVLSI.2003.812366 VL - 11 IS - 3 SP - 406-417 SN - 1557-9999 KW - current-mode KW - delay KW - interconnect KW - on-chip signaling KW - repeater ER - TY - JOUR TI - Asymptotic spectral efficiency of multicell MIMO systems with frequency-flat fading AU - Dai, HY AU - Poor, HV T2 - IEEE TRANSACTIONS ON SIGNAL PROCESSING AB - The spectral efficiency of multiple-input multiple-output (MIMO) systems operating in multicell frequency-flat fading environments is studied for situations in which co-channel interference is the dominant channel impairment instead of ambient noise. The following detectors are analyzed: the joint optimum detector, a group linear minimum-mean-square-error (MMSE) detector and its generalized version, a group MMSE successive interference cancellation detector, and an adaptive multiuser detector, with the focus on their large-system asymptotic (nonrandom) expressions. Analytical and numerical results based on these asymptotic multicell MIMO spectral efficiencies are explored to gain insights into the behavior of interference-limited multicell MIMO systems. DA - 2003/11// PY - 2003/11// DO - 10.1109/TSP.2003.818201 VL - 51 IS - 11 SP - 2976-2988 SN - 1053-587X KW - cellular communications KW - channel capacity KW - co-channel interference KW - large-system asymptotic analysis KW - MIMO systems KW - multiuser detection KW - spectral efficiency ER - TY - JOUR TI - A K a-band power amplifier based on a low-profile slotted-waveguide power-combining/dividing circuit AU - Jiang, X AU - Liu, L AU - Ortiz, SC AU - Bashirullah, R AU - Mortazawi, A T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - In this paper, a Ka-band power amplifier based on a resonant slotted-waveguide-to-microstrip power-dividing/combining circuit is presented. The advantages of this structure are its low profile, ease of fabrication, as well as its potential for high power-combining efficiency. In addition, efficient heat sinking of monolithic microwave integrated circuit (MMIC) devices is achieved. A slotted-waveguide power amplifier using eight MMIC amplifiers was designed and fabricated. The measured power-combining efficiency at 33 GHz is 72%. In addition, simulation results predicting the performance degradation of the slotted-waveguide power amplifier due to multiple device failure are presented. DA - 2003/1// PY - 2003/1// DO - 10.1109/TMTT.2002.806927 VL - 51 IS - 1 SP - 144-147 SN - 1557-9670 KW - K a-band KW - power amplifier KW - power combining KW - slotted waveguide ER - TY - JOUR TI - Observation of optical phonon instability induced by drifting electrons in semiconductor nanostructures AU - Liang, W. AU - Tsen, K. T. AU - Sankey, Otto F. AU - Komirenko, S. M. AU - Kim, K. W. AU - Kochelap, V. A. AU - Wu, Meng-Chyi AU - Ho, Chong-Long AU - Ho, Wen-Jeng AU - Morkoç, H. T2 - Applied Physics Letters AB - We have experimentally proven the Cerenkov generation of optical phonons by drifting electrons in a semiconductor. We observe an instability of the polar optical phonons in nanoscale semiconductors that occurs when electrons are accelerated to very high velocities by intense electric fields. The instability is observed when the electron drift velocity is larger than the phase velocity of optical phonons and rather resembles a “sonic boom” for optical phonons. The effect is demonstrated in p–i–n semiconductor nanostructures by using subpicosecond Raman spectroscopy. DA - 2003/3/24/ PY - 2003/3/24/ DO - 10.1063/1.1563730 VL - 82 IS - 12 SP - 1968-1970 J2 - Appl. Phys. Lett. LA - en OP - SN - 0003-6951 1077-3118 UR - http://dx.doi.org/10.1063/1.1563730 DB - Crossref ER - TY - JOUR TI - Meander-slot and U-slot antenna arrays for wide-band spatial power combiners AU - Yakovlev, AB AU - Lukic, MV AU - Elsherbeni, AZ AU - Smith, CE AU - Steer, MB T2 - IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS AB - In this work, we present a multilayered waveguide transition containing several interacting printed antenna arrays for spatial power combining applications. Narrow-band resonant rectangular slot antennas used in earlier designs are replaced by meander-slot antennas and their modifications, in order to increase the frequency bandwidth and efficiency of the system. Numerical results for finite arrays of meander-slot and U-slot antennas show significant advantages in scattering characteristics in comparison to traditionally used rectangular slot antenna arrays. DA - 2003/3// PY - 2003/3// DO - 10.1109/LMWC.2003.810125 VL - 13 IS - 3 SP - 125-127 SN - 1531-1309 KW - meander-slot antenna KW - method of moments KW - spatial power combining KW - U-slot antenna KW - waveguide transition ER - TY - JOUR TI - Manipulating theL-valley electrongfactor in Si-Ge heterostructures AU - Baron, F. A. AU - Kiselev, A. A. AU - Robinson, H. D. AU - Kim, K. W. AU - Wang, K. L. AU - Yablonovitch, E. T2 - Physical Review B AB - The Zeeman effect for the L valley conduction band electrons in SiGe heterostructures is considered. A detailed calculation of the electron g tensor is performed in the framework of a relevant $\mathit{k}\ensuremath{\cdot}\mathit{p}$ model, developed specifically for the L point of the Brillouin zone. Electrons at the L point are considered under the influence of the different crystallographic orientations, alloy composition, quantum confinement, strain, and electric field, whose interplay causes a considerable deviation of the g tensor components from their bulk values. Our result strongly suggests that the SiGe-based quantum wells are a promising choice for the g tensor engineering for spin manipulation. DA - 2003/11/6/ PY - 2003/11/6/ DO - 10.1103/physrevb.68.195306 VL - 68 IS - 19 SP - J2 - Phys. Rev. B LA - en OP - SN - 0163-1829 1095-3795 UR - http://dx.doi.org/10.1103/PhysRevB.68.195306 DB - Crossref ER - TY - JOUR TI - Control methodologies in networked control systems AU - Tipsuwan, Y. AU - Chow, M. Y. T2 - Control Engineering Practice DA - 2003/// PY - 2003/// DO - 10.1016/S0967-066190300036-4 VL - 11 IS - 10 SP - 1099-1111 ER - TY - JOUR TI - A nonlinear diffusion-based three-band filter bank AU - Benazza-Benyahia, A AU - Pesquet, JC AU - Krim, H T2 - IEEE SIGNAL PROCESSING LETTERS AB - In this letter, we revisit a number of concepts that have recently proven to be useful in multiresolution signal analysis, specifically by replacing the now classical linear-scale transition operators by nonlinear ones. More precisely, we address the problem of designing appropriate operators associated to nonlinear filter banks using multiscale analysis. We first establish a connection between nonlinear filter banks and partial differential equations operators used in scale-space theory. Toward this end, we propose specific structures of nonlinear three-band decompositions ensuring a perfect reconstruction. The behavior of the proposed structures is analyzed for a step-like signal in a high SNR scenario, and a simulation is proposed for a more complex scenario. DA - 2003/12// PY - 2003/12// DO - 10.1109/LSP.2003.818864 VL - 10 IS - 12 SP - 360-363 SN - 1558-2361 KW - diffusion KW - edge preservation KW - filter banks KW - multiresolution analysis KW - nonlinearity KW - partial differential equation (PDE) KW - Perona-Malik KW - scale-space KW - wavelets ER - TY - JOUR TI - The effect of contact resistance on current crowding and electromigration in ULSI multi-level interconnects AU - Huang, JS AU - Yeh, ECC AU - Zhang, ZB AU - Tu, KN T2 - MATERIALS CHEMISTRY AND PHYSICS AB - Electromigration (EM) has been the most persistent interconnect reliability issue over the decades. In general, EM damages tend to occur at atomic flux divergence sites. The EM failure rate can be further accelerated by current crowding, which occurs when current flows between inter-level wires. In this work, we used two different via etch schemes to study the effect of contact resistance on current crowding and EM. We found that the etch stop structures show longer EM lifetimes than the over etch. The contact resistance of the etch stop is higher than that of the over etch. Two-dimensional simulation results show that the higher contact resistance in the etch stop can suppress current crowding and improve EM lifetimes. Differences in void morphology between the over etch and etch stop as a result of current crowding are discussed. DA - 2003/1/15/ PY - 2003/1/15/ DO - 10.1016/S0254-0584(02)00018-4 VL - 77 IS - 2 SP - 377-383 SN - 0254-0584 KW - electromigration KW - ULSI KW - etch stop ER - TY - JOUR TI - Reduced size, dual-polarized microstrip patch antenna for wireless communications AU - Gosalia, K AU - Lazzi, G T2 - IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION AB - A novel, compact, probe-fed microstrip patch antenna for operation in dual-polarization mode is proposed. The novel design is achieved by etching out a symmetric pattern of crossed slots from the surface of a square probe-fed patch. Reduction in patch size of up to 51% with respect to a traditional dual-polarized square patch operating at the same frequency is obtained. Results show linear polarizations in the +45 and -45/spl deg/ with a high isolation of 38 dB between the two ports. Moreover, the 50-/spl Omega/ feed position can be achieved by moving the feed point along the diagonal of the square patch, leading to ease in fabrication. DA - 2003/9// PY - 2003/9// DO - 10.1109/TAP.2003.816344 VL - 51 IS - 9 SP - 2182-2186 SN - 1558-2221 KW - compact microstrip antenna KW - dual polarization ER - TY - JOUR TI - Planar gallium nitride ultraviolet optical modulator AU - Oberhofer, AE AU - Muth, JF AU - Johnson, MAL AU - Chen, ZY AU - Fleet, EF AU - Cooper, GD T2 - APPLIED PHYSICS LETTERS AB - A planar optical modulator operating near 360 nm suitable for ultraviolet spatial light modulation has been constructed. The modulator operates in transmission mode with a 18% change in transmission at 305 V. The modulator is based on using the electric field to shift and broaden the room-temperature resonance of the gallium nitride exciton with electric fields. DA - 2003/10/6/ PY - 2003/10/6/ DO - 10.1063/1.1615675 VL - 83 IS - 14 SP - 2748-2750 SN - 0003-6951 ER - TY - JOUR TI - Effect of the composition on the electrical properties of TaSixNy metal gate electrodes AU - Suh, YS AU - Heuss, GP AU - Lee, JH AU - Misra, V T2 - IEEE ELECTRON DEVICE LETTERS AB - In this letter, the effect of silicon and nitrogen on the electrical properties of TaSi/sub x/N/sub y/ gate electrode were investigated. The TaSi/sub x/N/sub y/ films were deposited on SiO/sub 2/ using reactive cosputtering of Ta and Si target in Ar and N/sub 2/ ambient. The thermal stability of TaSi/sub x/N/sub y//SiO/sub 2//p-type Si stacks was evaluated by measuring the flatband voltage and equivalent oxide thickness at 400/spl deg/C and 900/spl deg/C in Ar. It was found that under high temperature anneals, Si-rich TaSi/sub x/N/sub y/ films increased and this was attributed to the formation of a reaction layer at the electrode-dielectric interface. Reducing the Si content alone did not prevent the formation of this reaction layer while removing Si completely by utilizing TaN resulted in work functions that were too high. The presence of both Si and N was deemed necessary and their content was critical in obtaining optimized TaSi/sub x/N/sub y/ gates that are suitable for NMOS devices. DA - 2003/7// PY - 2003/7// DO - 10.1109/LED.2003.814009 VL - 24 IS - 7 SP - 439-441 SN - 1558-0563 KW - dual metal gates KW - gate Electrodes KW - low work function KW - MOS capacitors KW - N diffusion KW - TaSiN ER - TY - JOUR TI - Computed SAR and thermal elevation in a 0.25-mm 2-D model of the human eye and head in response to an implanted retinal stimulator - Part II: Results AU - Lazzi, G AU - DeMarco, SC AU - Liu, WT AU - Weiland, JD AU - Humayun, MS T2 - IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION AB - This is the second of a series of two papers on the thermal increase in the human eye and head in response to an implanted retinal stimulator. This paper provides specific absorption rates induced in the human head by the extraocular unit and the temperature increases associated with induced electromagnetic fields and power dissipation of the implanted microchip. Results are provided for different assumptions about choroid blood flow. It is shown that computed results associated with the power dissipation of the implanted microchip, corresponding to temperature increases of approximately 0.6/spl deg/C in the midvitreous of the eye and 0.2/spl deg/C in the retina, closely parallel in-vivo experimental results in animals. DA - 2003/9// PY - 2003/9// DO - 10.1109/TAP.2003.816394 VL - 51 IS - 9 SP - 2286-2295 SN - 0018-926X KW - age-related macular degeneration KW - finite-difference time domain (FDTD) KW - retina prosthesis KW - retinitis pigmentosa KW - specific absorption rate (SAR) KW - stimulator IC KW - temperature KW - thermal simulation ER - TY - JOUR TI - Computed SAR and thermal elevation in a 0.25-mm 2-D model of the human eye and head in response to an implanted retinal stimulator - Part I: Models and methods AU - DeMarco, SC AU - Lazzi, G AU - Liu, WT AU - Weiland, JD AU - Humayun, MS T2 - IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION AB - Retinitis pigmentosa and age-related macular degeneration lead to blindness through progressive loss of retinal photoreceptors. Attempts are under way to construct a visual prosthesis to recover a limited sense of vision for these patients with the aid of implantable electronic devices. The function of these microchips is to provide electrical stimulation to existing viable retinal tissues - living ganglion and bipolar cells - using an array of on-chip stimulus circuits, while the dominant mechanism for power and data communication for these implanted devices has been wireless inductive telemetry using coils. This paper describes methods and models used to estimate the heating induced in the human eye and surrounding head tissues subject to the operation of this retinal prosthesis. A two-dimensional 0.25-mm high-resolution human head model has been developed with the aid of a new semiautomatic graphical segmentation algorithm. Finite-difference-based numerical methods for both electromagnetic and thermal modeling have been used to determine the influence of the specific absorption rate (associated with 2-MHz inductive coupling to the implant) and of stimulator integrated circuit (IC) power on tissue heating under different operational conditions and different hypothesis on choroidal blood flow and properties of the complex implanted circuitry. Results, provided in Part II of this paper, show that temperature increases of approximately 0.6 and 0.4/spl deg/C are induced in the midvitreous of the human eye in the absence and presence of choroidal blood flow, respectively, for a 60-electrode retinal prosthesis chip. Correspondent temperature rises of approximately 0.19 and 0.004/spl deg/C on the retina are obtained for these cases. Comparison with in vivo experimental measurements on intraocular heating in dog eyes shows good agreement. DA - 2003/9// PY - 2003/9// DO - 10.1109/TAP.2003.816395 VL - 51 IS - 9 SP - 2274-2285 SN - 1558-2221 KW - age-related macular degeneration KW - finite-difference time domain (FDTD) KW - retina prosthesis KW - retinitis pigmentosa KW - specific absorption rate (SAR) KW - stimulator IC KW - temperature KW - thermal simulation ER - TY - JOUR TI - An arbitrary waveform stimulus circuit for visual prostheses using a low-area multibias DAC AU - DeMarco, SC AU - Liu, WT AU - Singh, PR AU - Lazzi, G AU - Humayun, MS AU - Weiland, JD T2 - IEEE JOURNAL OF SOLID-STATE CIRCUITS AB - Attempts are underway to construct a retinal prosthesis to recover limited vision for blind patients with retinitis pigmentosa using implantable electronic devices. These microchips provide electrical stimulation to damaged retinal tissues using an array of stimulus circuits. This paper describes improvements to conventional circuit designs with significantly decreased implementation area and the ability to support arbitrary stimulus waveforms where an array of such stimulus circuits is required. This yields greater spatial resolution in stimulation owing to more stimulus circuits per chip area. Also introduced are digital-to-analog converter gain prescalar and dc-offset circuits which tune the stimulus circuits to an optimally effective range due to variation in retinal degradation. The prototype chip was fabricated by MOSIS in 1.2-μm CMOS technology. DA - 2003/10// PY - 2003/10// DO - 10.1109/JSSC.2003.817264 VL - 38 IS - 10 SP - 1679-1690 SN - 0018-9200 KW - age-related macular degeneration KW - digital-to-analog converter (DAC) KW - electrical stimulation KW - retinal prosthesis KW - retinitis pigmentosa KW - visual prosthesis ER - TY - JOUR TI - Spin-lattice relaxation in Si quantum dots AU - Glavin, B. A. AU - Kim, K. W. T2 - Physical Review B AB - We consider spin-lattice relaxation processes for electrons trapped in lateral Si quantum dots in a $[001]$ inversion layer. Such dots are characterized by strong confinement in the direction perpendicular to the surface and much weaker confinement in the lateral direction. The spin relaxation is assumed to be due to the modulation of electron g-factor by the phonon-induced strain, as was shown previously for the shallow donors. The results clearly indicate that the specific valley structure of the ground electron state in Si quantum dots causes strong anisotropy for both the one-phonon and two-phonon spin-relaxation rates. In addition, it gives rise to a partial suppression of the two-phonon relaxation in comparison to the spin relaxation of donor electrons. DA - 2003/7/17/ PY - 2003/7/17/ DO - 10.1103/physrevb.68.045308 VL - 68 IS - 4 SP - J2 - Phys. Rev. B LA - en OP - SN - 0163-1829 1095-3795 UR - http://dx.doi.org/10.1103/PhysRevB.68.045308 DB - Crossref ER - TY - JOUR TI - Oxide formation and passivation for micro- and nano-electronic devices AU - Bae, C AU - Lucovsky, G T2 - APPLIED SURFACE SCIENCE AB - A low-temperature remote plasma-assisted oxidation process for interface formation and passivation has been extended from Si and SiC to GaN. The process, which can be applied to nano-scale structures including quantum dots and wires, provides excellent control of ultra-thin interfacial layers which passivate the GaN substrate, preventing a parasitic or subcutaneous oxidation of the substrate during plasma deposition of SiO2. The remote plasma processing for GaN–SiO2 heterostructures includes: (i) an in situ nitrogen plasma surface clean; (ii) a remote plasma-assisted oxidation for formation of an interfacial GaOx (x=1.5) transition region between the GaN and deposited dielectric; and (iii) a remote plasma-enhanced chemical vapor deposition of an SiO2 dielectric. DA - 2003/5/15/ PY - 2003/5/15/ DO - 10.1016/S0169-4332(03)00139-9 VL - 212 SP - 644-648 SN - 0169-4332 KW - plasma processing KW - Auger electron spectroscopy KW - semiconductor-insulator interfaces KW - interface states ER - TY - JOUR TI - Optimizing information efficiency in a direct-sequence mobile packet radio network AU - Chandra, MW AU - Hughes, BL T2 - IEEE TRANSACTIONS ON COMMUNICATIONS AB - We consider a direct-sequence multihop packet radio network using slotted ALOHA in a Rayleigh fading environment. We are interested in optimally choosing the transmission range, code rate, and slotted ALOHA transmission probability to be used by each node. We use a new performance measure, information efficiency, to analyze the network and show that the information efficiency of the low-cost mobile packet radio network can be improved approximately 20 fold by using the optimum parameters. We suggest a practical trellis-coded modulation scheme which comes close to realizing the theoretic limits found. DA - 2003/1// PY - 2003/1// DO - 10.1109/TCOMM.2002.807607 VL - 51 IS - 1 SP - 22-24 SN - 1558-0857 KW - direct-sequence modulation KW - spectral efficiency KW - spread-spectrum KW - trellis-coded modulation optimum transmission KW - ranges ER - TY - JOUR TI - Nonequilibrium Green's function formulation of quantum transport theory for multi-band semiconductors AU - Zhao, P AU - Horing, NJM AU - Woolard, DL AU - Cui, HL T2 - PHYSICS LETTERS A AB - Abstract We present a nonequilibrium Green's function formulation of many-body quantum transport theory for multi-band semiconductor systems with a phonon bath. The equations are expressed exactly in terms of single particle nonequilibrium Green's functions and self-energies, treating the open electron–hole system in weak interaction with the bath. A decoupling technique is employed to separate the individual band Green's function equations of motion from one another, with the band–band interaction effects embedded in “cross-band” self-energies. This nonequilibrium Green's function formulation of quantum transport theory is amenable to solution by parallel computing because of its formal decoupling with respect to inter-band interactions. Moreover, this formulation also permits coding the simulator of an n-band semiconductor in terms of that for an (n−1)-band system, in step with the current tendency and development of programming technology. Finally, the focus of these equations on individual bands provides a relatively direct route for the determination of carrier motion in energy bands, and to delineate the influence of intra- and inter-band interactions. A detailed description is provided for three-band semiconductor systems. DA - 2003/4/21/ PY - 2003/4/21/ DO - 10.1016/S0375-9601(03)00286-X VL - 310 IS - 4 SP - 258-264 SN - 0375-9601 KW - multi-band transport equations KW - nonequilibrium Green's function KW - decoupling technique KW - many-body KW - quantum transport ER - TY - JOUR TI - Forming shaped/molded structures by integrating meltblowing and robotic technologies AU - Farer, R AU - Seyam, AM AU - Ghosh, TK AU - Batra, SK AU - Grant, E AU - Lee, G T2 - TEXTILE RESEARCH JOURNAL AB - A novel system is described that forms three-dimensional (3D) molded nonwoven structures through proper integration of a laboratory scale meltblown unit with a small die and a six-axis robot. The 3D fiberweb structures can be formed by deposition of fibers from the die of the meltblown unit, which is manipulated by the robot, on any desired 3D mold. The mold rotational and surface speeds can be controlled by an additional external axis. The die is connected by two flexible hoses to the melt extruder of the meltblown unit and a hot air supply system. This system directly sprays fibers onto a 3D mannequin mold to produce structures from polypropylene polymers. With varying degrees of success. several robot manipulation algorithms of fiber deposition on the mold are developed to accurately control the basis weight uniformity the fiberwebs. A rule-based control algorithm using a linear variable differential transducer to map the mold contour results in the greatest fiberweb basis weight uniformity. DA - 2003/1// PY - 2003/1// DO - 10.1177/004051750307300103 VL - 73 IS - 1 SP - 15-21 SN - 0040-5175 ER - TY - JOUR TI - Electrical characterization of redox-active molecular monolayers on SiO2 for memory applications AU - Li, QL AU - Surthi, S AU - Mathur, G AU - Gowda, S AU - Misra, V AU - Sorenson, TA AU - Tenent, RC AU - Kuhr, WG AU - Tamaru, S AU - Lindsey, JS AU - Liu, ZM AU - Bocian, DF T2 - APPLIED PHYSICS LETTERS AB - Hybrid silicon capacitors have been successfully fabricated by attaching monolayers of redox-active molecules via self-assembly to ultrathin silicon dioxide layers. Capacitance, conductance, and cyclic voltammetric measurements have been used to characterize these capacitors. The presence of distinct capacitance and conductance peaks associated with oxidation and reduction of the monolayers at low gate voltages indicates discrete electron storage states for these capacitors, suggesting their feasibility in memory devices. The inherent molecular scalability and low-power operation coupled with existing silicon technology support the approach of hybrid molecule-silicon devices as a strong candidate for next generation electronic devices. DA - 2003/7/7/ PY - 2003/7/7/ DO - 10.1063/1.1584088 VL - 83 IS - 1 SP - 198-200 SN - 0003-6951 ER - TY - JOUR TI - Device-quality GaN-dielectric interfaces by 300 degrees C remote plasma processing AU - Bae, C AU - Rayner, GB AU - Lucovsky, G T2 - APPLIED SURFACE SCIENCE 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 (∼0.6 nm) and (ii) remote plasma enhanced chemical vapor deposition (RPECVD) to deposit the oxide film. The same approach has been applied to GaN–SiO2 system. Low-temperature (300 °C) remote N2/He plasma cleaning of the GaN surface, and the kinetics of GaN oxidation using RPAO process and subcutaneous oxidation during the SiO2 deposition using an RPECVD process have been investigated from analysis of on-line Auger electron spectroscopy (AES) features associated N and O. Compared to single-step SiO2 deposition, significantly reduced defect state densities are obtained at the GaN–dielectric interfaces by independent control of GaN–GaOx (x∼1.5) interface formation by RPAO, and SiO2 deposition by RPECVD. DA - 2003/6/30/ PY - 2003/6/30/ DO - 10.1016/S0169-4332(03)00497-5 VL - 216 IS - 1-4 SP - 119-123 SN - 1873-5584 KW - GaN-dielectric interfaces KW - surface leaning KW - subcutaneous oxidation KW - Ga2O3 KW - SiO2 KW - MOSd devices ER - TY - JOUR TI - Creation and quenching of interference-induced emitter-quantum wells within double-barrier tunneling structures AU - Zhao, PJ AU - Woolard, DL AU - Gelmont, BL AU - Cui, HL T2 - JOURNAL OF APPLIED PHYSICS AB - The initial creation and subsequent quenching of the emitter quantum well within double-barrier resonant tunneling structures (RTSs) is the key process that explains the origin of the hysteresis and plateau-like structure of the I–V characteristics. This fundamental process, which evolves out of quantum-mechanical interference, defines the basic mechanism that can lead to intrinsic high-frequency oscillations. This article presents numerical results, derived from a coupled Wigner–Poisson model, that illustrate the underlying mechanisms responsible for the creation and disappearance of the emitter-quantum well. Additional theoretical results are also given that demonstrates how subband state coupling, between the emitter-quantum well (EQW) and the main-quantum well (MQW) defined by the double-barrier heterostructure, leads to the hysteresis and instability behavior. This article will reveal how the quantum interference that develops between the incident and reflected electron wave function (i.e., from the first barrier) leads to the formation of an emitter-quantum well. An analysis is also performed to define the effects of EQW–MQW subband coupling on the current–density verses voltage (I–V) characteristics and the overall I–V dependence on the initial charging states of the individual wells. In particular, this analysis is used to show how the EQW is formed and quenched and how it influences the time-dependent behavior of the structure when it is subject to forward- and backward-bias sweeps of the applied bias voltages. This article provides fundamental quantum-mechanical explanations for the complicated time-dependent processes within double-barrier RTSs and provides insight into the hysteresis and intrinsic oscillation behavior. DA - 2003/8/1/ PY - 2003/8/1/ DO - 10.1063/1.1587003 VL - 94 IS - 3 SP - 1833-1849 SN - 0021-8979 ER - TY - JOUR TI - A generalized divergence measure for robust image registration AU - He, Y. AU - Hamza, A. B. AU - Krim, H. T2 - IEEE Transactions on Signal Processing AB - Entropy-based divergence measures have shown promising results in many areas of engineering and image processing. We define a new generalized divergence measure, namely, the Jensen-Renyi (1996, 1976) divergence. Some properties such as convexity and its upper bound are derived. Based on the Jensen-Renyi divergence, we propose a new approach to the problem of image registration. Some appealing advantages of registration by Jensen-Renyi divergence are illustrated, and its connections to mutual information-based registration techniques are analyzed. As the key focus of this paper, we apply Jensen-Renyi divergence for inverse synthetic aperture radar (ISAR) image registration. The goal is to estimate the target motion during the imaging time. Our approach applies Jensen-Renyi divergence to measure the statistical dependence between consecutive ISAR image frames, which would be maximal if the images are geometrically aligned. Simulation results demonstrate that the proposed method is efficient and effective. DA - 2003/// PY - 2003/// DO - 10.1109/TSP.2003.810305 VL - 51 IS - 5 SP - 1211-1220 ER - TY - JOUR TI - Structural dependence of breakdown characteristics and electrical degradation in ultrathin RPECVD oxide/nitride gate dielectrics under constant voltage stress AU - Lee, YM AU - Wu, YD AU - Bae, C AU - Hong, JG AU - Lucovsky, G T2 - SOLID-STATE ELECTRONICS AB - Abstract The structural dependence of breakdown characteristics and electrical degradation in ultrathin oxide/nitride (O/N) dielectrics, prepared by remote plasma enhanced chemical vapor deposition, is investigated under constant voltage stress. In the early stage of oxide wearout, soft breakdown is a local phenomenon dominated by the tunneling current. After a given period of stress, a strong channel-length dependence of dielectric breakdown and the corresponding stress-induced leakage current from the evolution of increased tunneling current have been found. Stacked O/N dielectrics with interface nitridation demonstrate improved device performance on subthreshold swing and threshold voltage shifts after stress, indicating the suppression of stress-induced traps at the oxide/Si and oxide/drain interfaces compared to thermal oxides. Experimental evidence shows more severe breakdown and device degradation in the threshold voltage, drain current and transconductance for shorter channel PMOSFETs with O/N dielectrics. These degradations result from the enhancement of hole trapping in the gate–drain overlap region as evidenced by a positive off-state leakage current, which leads to hard breakdown, and the complete failure of device functionality. DA - 2003/1// PY - 2003/1// DO - 10.1016/S0038-1101(02)00257-5 VL - 47 IS - 1 SP - 71-76 SN - 1879-2405 KW - dielectric degradation KW - soft breakdown KW - RPECVD oxide/nitride dielectric KW - stress-induced leakage current KW - constant voltage stress KW - hard breakdown ER - TY - JOUR TI - Optimal space-time constellations from groups AU - Hughes, BL T2 - IEEE TRANSACTIONS ON INFORMATION THEORY AB - We consider the design of space-time constellations based on group codes for fading channels with multiple transmit and receive antennas. These codes can be viewed as multiantenna extensions of phase-shift keying (PSK), in the sense that all codewords have equal energy, all are rotations of a fixed codeword, and there is a simple differential transmission rule that allows data to be sent without channel estimates at the transmitter or receiver. For coherent detection, we show that all optimal full-rank space-time group codes are unitary (each code matrix has equal-energy, orthogonal rows). This leads to a simpler code design criterion and suggests that unitary codes may play an important role in coherent as well as noncoherent communication. For any number of transmit antennas t, we then use the design criterion to characterize all full-rank unitary space-time group codes of minimum block length (also t) which have 2/sup p/ codewords. These results allow us to characterize all optimal 2/sup p/-ary unitary group codes with square code matrices. This restricted class of block codes matches the class proposed for differential modulation by Hughes (see IEEE Trans. Inform. Theory, vol.46, p.2567-78, Nov. 2000), and by Hochwald and Sweldens (see IEEE Trans. Commun., vol.48, p.2041-2052, Dec. 2000). DA - 2003/2// PY - 2003/2// DO - 10.1109/TIT.2002.807283 VL - 49 IS - 2 SP - 401-410 SN - 0018-9448 KW - constellation design KW - differential modulation KW - group codes KW - multipath channels KW - noncoherent communication KW - space-time coding KW - transmit diversity ER - TY - JOUR TI - Enhancement of hole injection for nitride-based light-emitting devices AU - Komirenko, S.M AU - Kim, K.W AU - Kochelap, V.A AU - Zavada, J.M T2 - Solid-State Electronics AB - A novel device design is proposed for a strong enhancement of hole injection current in nitride-based light-emitting heterostructures. Preliminary calculations show orders of magnitude increase in injected hole current when using the proposed superlattice hole injector device based on the real-space transfer concept. DA - 2003/1// PY - 2003/1// DO - 10.1016/S0038-1101(02)00314-3 VL - 47 IS - 1 SP - 169-171 J2 - Solid-State Electronics LA - en OP - SN - 0038-1101 UR - http://dx.doi.org/10.1016/S0038-1101(02)00314-3 DB - Crossref KW - UV emitter KW - group-III nitride KW - enhanced hole concentration KW - hole injection KW - superlattice ER - TY - JOUR TI - Effect of an external magnetic field on electron-spin dephasing induced by hyperfine interaction in quantum dots AU - Semenov, Y. G. AU - Kim, K. W. T2 - Physical Review B AB - We investigate the influence of an external magnetic field on spin-phase relaxation of single electrons in semiconductor quantum dots induced by the hyperfine interaction. The basic decay mechanism is attributed to the dispersion of local effective nuclear fields over the ensemble of quantum dots. The characteristics of electron-spin dephasing are analyzed by taking an average over the nuclear-spin distribution. We find that the dephasing rate can be estimated as a spin-precession frequency caused primarily by the mean value of the local nuclear magnetic field. Furthermore, it is shown that the hyperfine interaction does not fully depolarize electron spin. The loss of initial spin polarization during the dephasing process depends strongly on the external magnetic field, leading to the possibility of effective suppression of this mechanism. DA - 2003/2/12/ PY - 2003/2/12/ DO - 10.1103/physrevb.67.073301 VL - 67 IS - 7 SP - J2 - Phys. Rev. B LA - en OP - SN - 0163-1829 1095-3795 UR - http://dx.doi.org/10.1103/PhysRevB.67.073301 DB - Crossref ER - TY - JOUR TI - Voltage-controlled RF filters employing thin-film barium-strontium-titanate tunable capacitors AU - Tombak, A AU - Maria, JP AU - Ayguavives, FT AU - Jin, Z AU - Stauf, GT AU - Kingon, AI AU - Mortazawi, A T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - Tunable lowpass and bandpass lumped-element filters employing barium-strontium-titanate (BST)-based capacitors are presented. A new metallization technique is used, which improves the quality factor of the tunable BST capacitors by a factor of two. The lowpass filter has an insertion loss of 2 dB and a tunability of 40% (120-170 MHz) with the application of 0-9 V DC bias. The bandpass filter (BPF) has an insertion loss of 3 dB and a tunability of 57% (176-276 MHz) with the application of 0-6 V DC. The third-order intercept point of the BPF was measured to be 19 dBm with the application of two tones around 170 MHz. DA - 2003/2// PY - 2003/2// DO - 10.1109/TMTT.2002.807822 VL - 51 IS - 2 SP - 462-467 SN - 1557-9670 KW - barium-strontium-titanate.(BST) KW - ferroelectric KW - intermodulation distortion KW - metalorganic chemical vapor deposition (MOCVD) KW - multilayer ground plane KW - paraelectric KW - tunable bandpass filter (BPF) KW - tunable lowpass filter (LPF) ER - TY - JOUR TI - Printed antenna design for broadband waveguide-based spatial power combiners AU - Lukic, MV AU - Yakovlev, AB AU - Elsherbeni, AZ AU - Smith, CE AU - Steer, MB T2 - MICROWAVE AND OPTICAL TECHNOLOGY LETTERS AB - Abstract Design of broadband printed antennas, including the finite arrays of interacting patch, U‐strip, U‐slot, and meander slot antennas, are presented for applications in waveguide‐based spatial power combiners operating at X‐band. The effect of several antenna design parameters on antenna bandwidth performance is investigated in this paper. The antenna designs presented show significant advantages in their scattering characteristics compared to rectangular patch and slot antennas traditionally used in spatial power combiners. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 411–415, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10778 DA - 2003/3/5/ PY - 2003/3/5/ DO - 10.1002/mop.10778 VL - 36 IS - 5 SP - 411-415 SN - 0895-2477 KW - spatial power combining KW - meander-slot antenna KW - U-slot antenna KW - antenna array ER - TY - JOUR TI - Object representation and recognition in shape spaces AU - Zhang, J AU - Zhang, X AU - Krim, H AU - Walter, GG T2 - PATTERN RECOGNITION AB - In this paper, we describe a shape space based approach for invariant object representation and recognition. In this approach, an object and all its similarity transformed versions are identified with a single point in a high-dimensional manifold called the shape space. Object recognition is achieved by measuring the geodesic distance between an observed object and a model in the shape space. This approach produced promising results in 2D object recognition experiments: it is invariant to similarity transformations and is relatively insensitive to noise and occlusion. Potentially, it can also be used for 3D object recognition. DA - 2003/5// PY - 2003/5// DO - 10.1016/S0031-3203(02)00226-1 VL - 36 IS - 5 SP - 1143-1154 SN - 0031-3203 KW - shape space KW - object recognition KW - legendre polynomials KW - statistical shape analysis KW - invariants ER - TY - JOUR TI - Colonial posts AU - Wyrick, D. T2 - Jouvert : A Journal of Postcolonial Studies DA - 2003/// PY - 2003/// VL - 7 IS - 2 ER - TY - JOUR TI - The nominal capacity of wireless mesh networks AU - Jun, JG AU - Sichitiu, ML T2 - IEEE WIRELESS COMMUNICATIONS AB - Wireless mesh networks are an alternative technology for last-mile broadband Internet access. In WMNs, similar to ad hoc networks, each user node operates not only as a host but also as a router; user packets are forwarded to and from an Internet-connected gateway in multihop fashion. The meshed topology provides good reliability, market coverage, and scalability, as well as low upfront investments. Despite the recent startup surge in WMNs, much research remains to be done before WMNs realize their full potential. This article tackles the problem of determining the exact capacity of a WMN. The key concept we introduce to enable this calculation is the bottleneck collision domain, defined as the geographical area of the network that bounds from above the amount of data that can be transmitted in the network. We show that for WMNs the throughput of each node decreases as O(1/n), where n is the total number of nodes in the network. In contrast with most existing work on ad hoc network capacity, we do not limit our study to the asymptotic case. In particular, for a given topology and the set of active nodes, we provide exact upper bounds on the throughput of any node. The calculation can be used to provision the network, to ensure quality of service and fairness. The theoretical results are validated by detailed simulations. DA - 2003/10// PY - 2003/10// DO - 10.1109/mwc.2003.1241089 VL - 10 IS - 5 SP - 8-14 SN - 1558-0687 ER - TY - JOUR TI - T-shaped spin filter with a ring resonator AU - Kiselev, A. A. AU - Kim, K. W. T2 - Journal of Applied Physics AB - A planar ballistic T-shaped structure with a ring resonator attached is shown to be highly effective in filtering electron spin from an unpolarized source into two output fluxes with opposite and practically pure spin polarizations. The operability of the proposed device relies on the peculiar spin-dependent transmission properties of the T-shaped connector in the presence of Rashba spin–orbit interaction as well as the difference in dynamic phase gain of the two alternative paths around the ring resonator through upper and lower branches for even and odd eigenmodes. DA - 2003/9/15/ PY - 2003/9/15/ DO - 10.1063/1.1601313 VL - 94 IS - 6 SP - 4001-4005 J2 - Journal of Applied Physics LA - en OP - SN - 0021-8979 1089-7550 UR - http://dx.doi.org/10.1063/1.1601313 DB - Crossref ER - TY - JOUR TI - Space diversity in presence of discrete multipath fading channel AU - Cozzo, C AU - Hughes, BL T2 - IEEE TRANSACTIONS ON COMMUNICATIONS AB - Most analytical studies of the performance of space diversity systems on fading channels assume a very rich multipath environment. In certain wireless applications, however, the number of significant multipath components can be small. In this letter, we consider a multipath channel in which the signal propagates from the transmitter to the receiver via L discrete paths which are uniformly distributed about the transmitter and receiver. For this channel, we study the effects of the number of multipath components and antenna array size on the error probability and outage capacity of space diversity systems. We observe that performance is significantly influenced by the presence of a channel with few multipath components. DA - 2003/10// PY - 2003/10// DO - 10.1109/TCOMM.2003.818101 VL - 51 IS - 10 SP - 1629-1632 SN - 1558-0857 KW - fading channels KW - receive diversity KW - space-time coding KW - transmit diversity ER - TY - JOUR TI - NanoCell electronic memories AU - Tour, JM AU - Cheng, L AU - Nackashi, DP AU - Yao, YX AU - Flatt, AK AU - St Angelo, SK AU - Mallouk, TE AU - Franzon, PD T2 - JOURNAL OF THE AMERICAN CHEMICAL SOCIETY AB - NanoCells are disordered arrays of metallic islands that are interlinked with molecules between micrometer-sized metallic input/output leads. In the past, simulations had been conducted showing that the NanoCells may function as both memory and logic devices that are programmable postfabrication. Reported here is the first assembly of a NanoCell with disordered arrays of molecules and Au islands. The assembled NanoCells exhibit reproducible switching behavior and two types of memory effects at room temperature. The switch-type memory is characteristic of a destructive read, while the conductivity-type memory features a nondestructive read. Both types of memory effects are stable for more than a week at room temperature, and bit level ratios (0:1) of the conductivity-type memory have been observed to be as high as 10(4):1 and reaching 10(6):1 upon ozone treatment, which likely destroys extraneous leakage pathways. Both molecular electronic and nanofilamentary metal switching mechanisms have been considered, though the evidence points more strongly toward the latter. The approach here demonstrates the efficacy of a disordered nanoscale array for high-yielding switching and memory while mitigating the arduous task of nanoscale patterning. DA - 2003/10/29/ PY - 2003/10/29/ DO - 10.1021/ja036369g VL - 125 IS - 43 SP - 13279-13283 SN - 1520-5126 ER - TY - JOUR TI - Joint channel estimation and data detection in space-time communications AU - Cozzo, C AU - Hughes, BL T2 - IEEE TRANSACTIONS ON COMMUNICATIONS AB - The paper considers joint channel estimation and data sequence detection for multipath radio channels with multiple antennas at the transmitter and/or receiver. An iterative space-time receiver based on the expectation-maximization algorithm is proposed. We examine the performance of this receiver for transmit diversity and space-time coding methods over Rayleigh fading channels. Simulation results show that the receiver can often achieve near-coherent performance with modest complexity and using very few pilot symbols. DA - 2003/8// PY - 2003/8// DO - 10.1109/TCOMM.2003.815062 VL - 51 IS - 8 SP - 1266-1270 SN - 0090-6778 KW - expectation-maximization (EM) algorithm KW - fading channels KW - iterative receivers KW - joint detection and estimation KW - space-time coding KW - transmit diversity ER - TY - JOUR TI - Gain adaptation of networked DC motor controllers based on QOS variations AU - Chow, MY AU - Tipsuwan, Y T2 - IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS AB - Connecting a complex control system with various sensors, actuators, and controllers as a networked control system by a shared data network can effectively reduce complicated wiring connections. This system is also easy to install and maintain. The trend is to use networked control systems for time-sensitive applications, such as remote DC motor actuation control. The performance of a networked control system can be improved if the network can guarantee quality-of-service (QoS). Due to time-varying network traffic demands and disturbances, QoS requirements provided by a network may change. In this case, a network has to reallocate its resources and may not be able to provide QoS requirements to a networked control application as needed. Therefore, the application may have to gracefully degrade its performance and perform the task as best as possible with the provided network QoS. This paper proposes a novel approach for networked DC motor control systems using controller gain adaptation to compensate for the changes in QoS requirements. Numerical and experimental simulations, and prototyping, are presented to demonstrate the feasibility of the proposed adaptation scheme to handle network QoS variation in a control loop. The effective results show the promising future of the use of gain adaptation in networked control applications. DA - 2003/10// PY - 2003/10// DO - 10.1109/TIE.2003.817576 VL - 50 IS - 5 SP - 936-943 SN - 1557-9948 KW - adaptive control KW - communication networks KW - control systems KW - dc motors KW - decentralized control KW - distributed control KW - real-time systems KW - stability ER - TY - JOUR TI - Discovering and exploiting program phases AU - Sherwood, T AU - Perelman, E AU - Hamerly, G AU - Sair, S AU - Calder, B T2 - IEEE MICRO AB - Understanding program behavior is at the foundation of computer architecture and program optimization. Many programs have wildly different behavior on even the largest of scales (that is, over the program's complete execution). During one part of the execution, a program can be completely memory bound; in another, it can repeatedly stall on branch mispredicts. Average statistics gathered about a program might not accurately picture where the real problems lie. This realization has ramifications for many architecture and compiler techniques, from how to best schedule threads on a multithreaded machine, to feedback-directed optimizations, power management, and the simulation and test of architectures. Taking advantage of time-varying behavior requires a set of automated analytic tools and hardware techniques that can discover similarities and changes in program behavior on the largest of time scales. The challenge in building such tools is that during a program's lifetime it can execute billions or trillions of instructions. How can high-level behavior be extracted from this sea of instructions? Some programs change behavior drastically, switching between periods of high and low performance, yet system design and optimization typically focus on average system behavior. It is argued that instead of assuming average behavior, it is now time to model and optimize phase-based program behavior. DA - 2003/// PY - 2003/// DO - 10.1109/MM.2003.1261391 VL - 23 IS - 6 SP - 84-93 SN - 1937-4143 ER - TY - JOUR TI - Characterization of cross modulation in multichannel amplifiers using a statistically based behavioral modeling technique AU - Gharaibeh, KM AU - Steer, MB T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - A statistically based modeling technique is developed for characterizing in-band and out-of-band intermodulation and cross-modulation distortions in multichannel amplifier environments. The model is based on a new multiple envelope memoryless behavioral model that captures the black-box characteristics of multichannel amplifiers. A power amplifier with a two code-division multiple-access channel signal is characterized experimentally and verifies the approach. DA - 2003/12// PY - 2003/12// DO - 10.1109/TMTT.2003.819195 VL - 51 IS - 12 SP - 2434-2444 SN - 1557-9670 KW - behavioral modeling KW - code division multiple access (CDMA) KW - cross-modulation distortion KW - multichannel KW - nonlinear systems KW - power amplifiers KW - statistical modeling ER - TY - JOUR TI - Adaptive demosaicking AU - Ramanath, R AU - Snyder, WE T2 - JOURNAL OF ELECTRONIC IMAGING AB - The Journal of Electronic Imaging (JEI), copublished bimonthly with the Society for Imaging Science and Technology, publishes peer-reviewed papers that cover research and applications in all areas of electronic imaging science and technology. DA - 2003/10// PY - 2003/10// DO - 10.1117/1.1606459 VL - 12 IS - 4 SP - 633-642 SN - 1017-9909 ER - TY - JOUR TI - The epHEMT gate at microwave frequencies AU - Wartenberg, SA AU - Hauser, , JR T2 - IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES AB - This paper examines the high-frequency behavior of the enhancement-mode pseudomorphic high electron-mobility transistor (epHEMT) gate. During this study, no bias was applied between the drain and source. Rather, the gate was forward biased with either the drain, source, or channel (drain and source connected together) grounded. While applying positive voltage V/sub g/ to the gate, one-port S-parameters were measured from 0.1 to 10 GHz and then converted to Z-parameters. Plotting the real part R of the impedance reveals two sharp peaks. The first peak occurs near the device threshold voltage for conduction in the InGaAs well. A second peak occurs at higher voltages where conduction begins to occur in the surface AlGaAs layer. An equivalent-circuit model is proposed to account for the epHEMT gate's high-frequency behavior and the proposed model is shown to be in good agreement with the experimental data. DA - 2003/6// PY - 2003/6// DO - 10.1109/TMTT.2003.812573 VL - 51 IS - 6 SP - 1718-1723 SN - 1557-9670 KW - enhancement mode KW - forward turn-on voltage KW - gate KW - heterojunction FET KW - pseudomorphic ER - TY - JOUR TI - Modeling value speculation: An optimal edge selection problem AU - Fu, CY AU - Bodine, JT AU - Conte, TM T2 - IEEE TRANSACTIONS ON COMPUTERS AB - Techniques for value speculation have been proposed for dynamically scheduled and statically scheduled machines to increase instruction-level parallelism (ILP) by breaking flow (true) dependences and allowing value-dependent operations to be executed speculatively. The effectiveness of value speculation depends upon the ability to select and break dependences to shorten overall execution time, while encountering penalties for value misprediction. To understand and improve the techniques for value speculation, we model value speculation as an optimal edge selection problem. The optimal edge selection problem involves finding a minimal set of edges (dependences) to break in a data dependence graph that achieves maximal benefits from value speculation, while taking the penalties for value misprediction into account. Based on three properties observed from the optimal edge selection problem, an efficient optimal edge selection algorithm is designed. From the experimental results of running the optimal edge selection algorithm for the 20 most heavily executed paths selected from each SPECint95 benchmark, several insights are shown. The average critical path reduction is 9.61 percent on an average and 25.57 percent at its maximum. Surprisingly, 66 percent of the edges selected by the optimal algorithm have value prediction accuracies over 99 percent. Moreover, most of the selected edges cross the middle of the data dependence graph. The selected producer operations thereby tend to reside in the upper portion of the data dependence graph, while the selected consumer operations appear toward the lower portion. DA - 2003/3// PY - 2003/3// DO - 10.1109/TC.2003.1183944 VL - 52 IS - 3 SP - 277-292 SN - 0018-9340 KW - value prediction KW - value speculation KW - optimal edge selection KW - data dependence graph KW - critical path reduction ER - TY - JOUR TI - Fast minimization of structural risk by nearest neighbor rule AU - Karacali, B AU - Krim, H T2 - IEEE TRANSACTIONS ON NEURAL NETWORKS AB - In this paper, we present a novel nearest neighbor rule-based implementation of the structural risk minimization principle to address a generic classification problem. We propose a fast reference set thinning algorithm on the training data set similar to a support vector machine (SVM) approach. We then show that the nearest neighbor rule based on the reduced set implements the structural risk minimization principle, in a manner which does not involve selection of a convenient feature space. Simulation results on real data indicate that this method significantly reduces the computational cost of the conventional SVMs, and achieves a nearly comparable test error performance. DA - 2003/1// PY - 2003/1// DO - 10.1109/TNN.2002.804315 VL - 14 IS - 1 SP - 127-137 SN - 1941-0093 KW - breast cancer detection KW - index set thinning algorithm KW - multivariate order statistics KW - nearest neighbor rule KW - support vector machine (SVM) ER - TY - JOUR TI - Design of a 20-Mb/s 256-state Viterbi decoder AU - Liu, X AU - Papaefthymiou, MC T2 - IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS AB - The design of high-throughput large-state Viterbi decoders relies on the use of multiple arithmetic units. The global communication channels among these parallel processors often consist of long interconnect wires, resulting in large area and high power consumption. In this paper, we propose a data transfer oriented design methodology to implement a low-power 256-state rate-1/3 Viterbi decoder. Our architectural level scheme uses operation partitioning, packing, and scheduling to analyze and optimize interconnect effects in early design stages. In comparison with other published Viterbi decoders, our approach reduces the global data transfers by up to 75% and decreases the amount of global buses by up to 48%, while enabling the use of deeply pipelined datapaths with no data forwarding. In the register-transfer level (RTL) implementation, we apply precomputation in conjunction with saturation arithmetic to further reduce power dissipation with provably no coding performance degradation. Designed using a 0.25 /spl mu/m standard cell library, our decoder achieves a throughput of 20 Mb/s in simulation and dissipates only 0.45 W. DA - 2003/12// PY - 2003/12// DO - 10.1109/TVLSI.2003.817547 VL - 11 IS - 6 SP - 965-975 SN - 1557-9999 KW - bus reduction KW - communications KW - data transfer KW - low power KW - pipelining ER - TY - JOUR TI - DC distribution for industrial systems: Opportunities and challenges AU - Baran, ME AU - Mahajan, NR T2 - IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS AB - This paper investigates the opportunities and challenges associated with adopting a DC distribution scheme for industrial power systems. A prototype DC distribution system has been simulated to investigate the issues. One of the issues focused is the interaction between power converters that are used to convert AC to DC and DC to AC. Another challenging issue investigated is the system grounding. These issues become challenging mainly due to the neutral voltage shift associated with the power converters. The paper shows that converter interactions can be minimized with proper filtering and control on the converters. The paper also proposes a grounding scheme and shows that this scheme provides an effective solution by keeping the neutral voltages low under normal conditions and by limiting the fault currents during fault conditions. With these features, DC distribution provides very reliable and high-quality power. DA - 2003/// PY - 2003/// DO - 10.1109/TIA.2003.818969 VL - 39 IS - 6 SP - 1596-1601 SN - 1939-9367 KW - DC systems KW - power electronics KW - transient analysis ER - TY - JOUR TI - Computing call-blocking probabilities in LEO satellite constellation's AU - Zaim, AH AU - Perros, HG AU - Rouskas, GN T2 - IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY AB - We present an analytical model for computing call-blocking probabilities in a low Earth orbit (LEO) satellite network that carries voice calls. Both satellite-fixed and Earth-fixed constellations with interorbit links and handoffs are considered. We assume a single beam per satellite. Also, we assume that call arrivals are Poisson with a fixed arrival rate that is independent of the geographic area. The model is analyzed approximately by decomposing it into subsystems. Each subsystem is solved in isolation exactly using a Markov process and the individual results are combined together through an iterative method. Numerical results demonstrate that our method is accurate for a wide range of traffic patterns. We also derive an upper and lower bound for the link-blocking probabilities that can be computed efficiently. These bounds can be used for constellations of realistic size where each satellite has multiple beams. DA - 2003/5// PY - 2003/5// DO - 10.1109/TVT.2003.811219 VL - 52 IS - 3 SP - 622-636 SN - 1939-9359 KW - call blocking KW - handoffs KW - low earth orbit (LEO) satellite constellations ER - TY - JOUR TI - Cattle, crime and colonialism: Property as negotiation in north India AU - Gilmartin, D T2 - INDIAN ECONOMIC AND SOCIAL HISTORY REVIEW AB - Cattle theft was a common crime in British India, and yet one marked by contradictions. While the protection of property was for many a defining feature of the modern state, colonial administrators were often loath to interfere in the negotiations by which Indians commonly arranged the return of stolen cattle. By examining one important prosecution of cattle theft in Punjab's Karnal district in 1913, this article argues that the state, local communities and individuals negotiated the meaning of property at multiple levels. Property was not a fixed concept, but rather a field of negotiation in which the relationship of state, community and individual were tiefined. DA - 2003/// PY - 2003/// DO - 10.1177/001946460304000102 VL - 40 IS - 1 SP - 33-56 SN - 0019-4646 ER - TY - JOUR TI - Advanced signal processing for power line communications AU - Dai, H. Y. AU - Poor, H. V. T2 - IEEE Communications Magazine AB - In this article, signal processing techniques to combat the adverse communications environment on power lines are addressed, so as to enable reliable high speed data communications over low-voltage power distribution networks for Internet access and in-home/office networking. It is seen that multicarrier code-division multiple access, multiuser detection, and turbo decoding, having demonstrated their limit-approaching capacity in DSL and wireless communication systems, are readily applied to power line communications. In particular, it is argued that these methods can successfully mitigate the influence of the principal impairments in PLC channels: time-varying channel attenuation, multipath frequency-selective fading, multiple access interference, and background noise. Strategies to deal with the most unfavorable noise source, the impulse noise, are also discussed. DA - 2003/// PY - 2003/// DO - 10.1109/mcom.2003.1200108 VL - 41 IS - 5 SP - 100-107 ER - TY - JOUR TI - A modified unsplit PML formulation for evanescent mode absorption in waveguides AU - Ozkar, M AU - Lazzi, G AU - Mortazawi, A T2 - IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS AB - In this letter, a modified unsplit perfectly matched layer (PML) formulation for the absorption of evanescent waves in waveguides is presented. The proposed formulation combines the advantages of the stretched coordinate and unsplit D - E - H PML formulations, which separates PML conductivities from the properties of the physical materials in the FDTD mesh. Results show that the proposed boundary outperforms the traditional unsplit PML in the evanescent region by 20 to 40 dB. DA - 2003/6// PY - 2003/6// DO - 10.1109/LMWC.2003.814109 VL - 13 IS - 6 SP - 220-222 SN - 1531-1309 KW - evanescent waves KW - FDTD KW - unsplit PML ER -