TY - JOUR
TI - Worst-Case Fair Bin Sort Queuing (WBSQ): An O(1) Worst-Case Fair Scheduler
AU - Dwekat, Zyad A.
AU - Rouskas, George N.
AU - IEEE
T2 - 2011 Ieee International Conference on Communications (Icc)
DA - 2011///
PY - 2011///
ER -
TY - JOUR
TI - On Optimal Tiered Structures for Network Service Bundles
AU - Lv, Qian
AU - Rouskas, George N.
AU - IEEE
T2 - 2011 Ieee Global Telecommunications Conference (Globecom 2011)
DA - 2011///
PY - 2011///
ER -
TY - JOUR
TI - Hybrid FRR/p-Cycle MPLS Link Protection Design
AU - Cao, Chang
AU - Rouskas, George N.
AU - IEEE
T2 - 2011 Ieee Global Telecommunications Conference (Globecom 2011)
DA - 2011///
PY - 2011///
ER -
TY - JOUR
TI - Flow Isolation in Optical Networks
AU - Wang, Hui
AU - Rouskas, George N.
AU - IEEE
T2 - 2011 18th Ieee Workshop on Local and Metropolitan Area Networks (Lanman)
DA - 2011///
PY - 2011///
ER -
TY - JOUR
TI - Demonstration of QoS-Aware Video Streaming over a Metro-Scale Optical Network Using a Cross-Layer Architectural Design
AU - Wang, Michael S.
AU - Wang, Anjing
AU - Bathula, Balagangadhar G.
AU - Lai, Caroline P.
AU - Baldine, Ilia
AU - Chen, Cathy
AU - Majumder, Debjyoti
AU - Gurkan, Deniz
AU - Rouskas, George N.
AU - Dutta, Rudra
AU - Bergman, Keren
AU - America, Optical Society
T2 - 2011 Optical Fiber Communication Conference and Exposition (Ofc/nfoec) and the National Fiber Optic Engineers Conference
DA - 2011///
PY - 2011///
ER -
TY - SOUND
TI - Production Planning with Resources Subject to Congestion
AU - Uzsoy, R.
DA - 2011/3//
PY - 2011/3//
ER -
TY - SOUND
TI - Production Planning with Resources Subject to Congestion
AU - Uzsoy, R.
DA - 2011/9//
PY - 2011/9//
ER -
TY - SOUND
TI - Heuristics for Multiproduct Dynamic Lot Sizing with Congestion
AU - Kang, Y.
AU - Albey, E.
AU - Hwang, S.
AU - Uzsoy, R.
DA - 2011/7//
PY - 2011/7//
ER -
TY - SOUND
TI - Production Planning with Workload-Dependent Lead Times and Uncertain Demand
AU - Uzsoy, R.
DA - 2011/12//
PY - 2011/12//
ER -
TY - CONF
TI - Geography in Healthcare Planning
AU - Carr, S.
AU - Gultekin, M.
AU - Roberts, S.
AU - Uzsoy, R.
T2 - Industrial Engineering Research Conference
C2 - 2011/5//
CY - Reno, NV
DA - 2011/5//
PY - 2011/5//
ER -
TY - CONF
TI - Modelling the Effect of Public Health Resources on the Dynamic of Pertussis Outbreaks
AU - Yaylali, E.
AU - Uzsoy, R.
AU - Worth, T.
AU - Maillard, J.M.
AU - Meyer, A.M.
AU - Samoff, E.
AU - Wendelboe, A.
T2 - INFORMS Conference on Healthcare
C2 - 2011/6//
CY - Montreal, Quebec, Canada
DA - 2011/6//
PY - 2011/6//
ER -
TY - BOOK
TI - Planning in the Extended Enterprise: A State of the Art Handbook
A3 - Kempf, K.G.
A3 - Keskinocak, P.
A3 - Uzsoy, R.
DA - 2011///
PY - 2011///
VL - 2
PB - Springer
ER -
TY - CONF
TI - Estimating Clearing Functions for Multistage Production Systems with Alternative Machines
AU - Albey, E.
AU - Bilge, U.
AU - Uzsoy, R.
T2 - INFORMS National Meeting
C2 - 2011/11//
CY - Charlotte, NC
DA - 2011/11//
PY - 2011/11//
ER -
TY - CONF
TI - A New Genetic Algorithm for Multicriteria Project Selection and Scheduling
AU - Viktorovna, N.
AU - Gaytan Iniestra, J.
AU - Uzsoy, R.
T2 - INFORMS National Meeting
C2 - 2011/11//
CY - Charlotte, NC
DA - 2011/11//
PY - 2011/11//
ER -
TY - CONF
TI - Modeling the Conditional Covariance of Demands with Application to Production Planning
AU - Norouzi, A.
AU - Uzsoy, R.
T2 - INFORMS National Meeting
C2 - 2011/11//
CY - Charlotte, NC
DA - 2011/11//
PY - 2011/11//
ER -
TY - CONF
TI - Modeling the Effect of Public Health Resources and Alerting on the Dynamics of Pertussis Spread
AU - Yaylali, E.
AU - Ivy, J.S.
AU - Uzsoy, R.
T2 - INFORMS National Meeting
C2 - 2011/11//
CY - Charlotte, NC
DA - 2011/11//
PY - 2011/11//
ER -
TY - CONF
TI - A Nonlinear Knapsack Problem Arising in Location Problems with Safety Stocks
AU - Jarugumilli, K.
AU - Uzsoy, R.
T2 - INFORMS National Meeting
C2 - 2011/11//
CY - Charlotte, NC
DA - 2011/11//
PY - 2011/11//
ER -
TY - CONF
TI - Estimating Clearing Functions from Simulation Data
AU - Kacar, N.B.
AU - Uzsoy, R.
T2 - INFORMS National Meeting
C2 - 2011/11//
CY - Charlotte, NC
DA - 2011/11//
PY - 2011/11//
ER -
TY -
ER -
TY -
ER -
TY - JOUR
TI - Production planning with load-dependent lead times and safety stocks for a single product
AU - Ravindran, Ashwin
AU - Kempf, Karl G.
AU - Uzsoy, Reha
T2 - International Journal of Planning and Scheduling
AB - Queuing models have demonstrated the nonlinear relationship between resource utilisation, which is determined by production planning decisions, and lead times. Both production planning decisions and safety stock levels are driven by lead times, and are thus tightly interrelated. However, production planning and safety stock calculations have generally been carried out separately. We propose a production planning model for a singlestage singleproduct system that integrates release planning and safety stock considerations. Concave clearing functions are used to capture the nonlinear relationship between resource utilisation and lead times, while chance constraints represent the need to plan inventories to achieve desired service levels. Extensive computational experiments indicate that the proposed model provides an excellent tradeoff between customer service and inventory costs.
DA - 2011///
PY - 2011///
DO - 10.1504/ijps.2011.044547
VL - 1
IS - 1/2
SP - 58
J2 - IJPS
LA - en
OP -
SN - 2044-494X 2044-4958
UR - http://dx.doi.org/10.1504/ijps.2011.044547
DB - Crossref
ER -
TY - JOUR
TI - Quality of service-based multi-domain routing under multiple quality of service metrics
AU - Yiltas, D.
AU - Perros, H.
T2 - IET Communications
AB - Applications such as voice and video require network paths that satisfy several different quality of service (QoS) metrics, such as delay, jitter, packet loss rate and availability. The calculation of paths under multiple QoS metrics, such as the above four metrics, is a difficult problem since these metrics are in general incompatible. The authors propose a simple method for combining the above four QoS metrics into a single composite QoS metric which can be used as a link cost in Dijkstra's algorithm in order to calculate a path. The authors evaluated the proposed method in a multi-domain routing environment where domain reachability information is available through a service oriented architecture paradigm, and they show that it outperforms two commonly used methods. The results are also applicable to routing within a single domain.
DA - 2011/2/11/
PY - 2011/2/11/
DO - 10.1049/iet-com.2010.0144
VL - 5
IS - 3
SP - 327-336
LA - en
OP -
SN - 1751-8628 1751-8636
UR - http://dx.doi.org/10.1049/iet-com.2010.0144
DB - Crossref
ER -
TY - CONF
TI - Toward the development of a commercial system to effectively harvest small- diameter woody biomass for energy production, habitat management and wildfire risk reduction
AU - Catts, G.
AU - Roise, Joseph
AU - Hannum, L.
T2 - TAPPI International Bioenergy & Bioproducts Conference
C2 - 2011/3/14/
CY - Atlanta, GA
DA - 2011/3/14/
PY - 2011/3/14/
ER -
TY - CONF
TI - Commitments with Regulations: Reasoning about Safety and Control in R EGULA
AU - Marengo, Elisa
AU - Baldoni, Matteo
AU - Chopra, Amit K.
AU - Baroglio, Cristina
AU - Patti, Viviana
AU - Singh, Munindar P.
T2 - International Conference on Autonomous Agents and MultiAgent Systems
C2 - 2011/5//
C3 - Proceedings of the 10th International Conference on Autonomous Agents and MultiAgent Systems (AAMAS)
CY - Taipei, Taiwan
DA - 2011/5//
PY - 2011/5//
SP - 467–474
PB - IFAAMAS
ER -
TY - CONF
TI - A Unified Framework for Trust in Composite Networks
AU - Adalı, Sibel
AU - Wallace, William A.
AU - Qi, Yi
AU - Vijayakumar, Priyankaa
AU - Singh, Munindar P.
T2 - Autonomous Agents & Multi-Agent Systems Workshop on Trust in Agent Societies
C2 - 2011///
C3 - Proceedings of the 13th Autonomous Agents & Multi-Agent Systems Workshop on Trust in Agent Societies
CY - Taipei, Taiwan
DA - 2011///
PY - 2011/5/2/
SP - 1–12
ER -
TY - CONF
TI - Optimal ordering policy with multiple unreliable suppliers
AU - Wang, Y.
AU - King, R.E.
AU - Ahiska, S.S.
AU - Warsing, D.P.
C2 - 2011///
C3 - 61st Annual IIE Conference and Expo Proceedings
DA - 2011///
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900342045&partnerID=MN8TOARS
ER -
TY - JOUR
TI - CAUSES OF FOURTH AGED PATIENTS HOSPITALIZATION IN AN INTERNAL MEDICINE HOSPITAL CLINIC
AU - Bristianou, Magdalini
AU - Panou, Charalambos
AU - Chatzidakis, Ioannis
AU - Tsiligrou, Vaina
AU - Theodosopoulos, Ioannis
AU - Rouskas, Georgios
AU - Liaskoni, Constantina
AU - Lanaras, Leonidas
T2 - European Journal of Internal Medicine
DA - 2011/10//
PY - 2011/10//
DO - 10.1016/S0953-6205(11)60442-1
VL - 22
SP - S108-S109
J2 - European Journal of Internal Medicine
LA - en
OP -
SN - 0953-6205
UR - http://dx.doi.org/10.1016/S0953-6205(11)60442-1
DB - Crossref
ER -
TY - JOUR
TI - Elsevier OSN is Sad to Announce the Loss of Fabio Neri, co-Editor-in-Chief of the Journal, Distinguished Professor and Researcher
AU - Bianco, Andrea
AU - Jukan, Admela
AU - Rouskas, George
T2 - Optical Switching and Networking
DA - 2011/12//
PY - 2011/12//
DO - 10.1016/j.osn.2011.09.001
VL - 8
IS - 4
SP - 286-287
J2 - Optical Switching and Networking
LA - en
OP -
SN - 1573-4277
UR - http://dx.doi.org/10.1016/j.osn.2011.09.001
DB - Crossref
ER -
TY - JOUR
TI - On an identity of Gessel and Stanton and the new little Göllnitz identities
AU - Savage, Carla D.
AU - Sills, Andrew V.
T2 - Advances in Applied Mathematics
AB - We show that an identity of Gessel and Stanton [I. Gessel, D. Stanton, Applications of q -Lagrange inversion to basic hypergeometric series, Trans. Amer. Math. Soc. 277 (1983) 197, Eq. (7.24)] can be viewed as a symmetric version of a recent analytic variation of the little Göllnitz identities. This is significant, since the Göllnitz–Gordon identities are considered the usual symmetric counterpart to little Göllnitz theorems. Is it possible, then, that the Gessel–Stanton identity is part of an infinite family of identities like those of Göllnitz–Gordon? Toward this end, we derive partners and generalizations of the Gessel–Stanton identity. We show that the new little Göllnitz identities enumerate partitions into distinct parts in which even-indexed (resp. odd-indexed) parts are even, and derive a refinement of the Gessel–Stanton identity that suggests a similar interpretation is possible. We study an associated system of q -difference equations to show that the Gessel–Stanton identity and its partner are actually two members of a three-element family.
DA - 2011/1//
PY - 2011/1//
DO - 10.1016/j.aam.2009.12.009
VL - 46
IS - 1-4
SP - 563-575
J2 - Advances in Applied Mathematics
LA - en
OP -
SN - 0196-8858
UR - http://dx.doi.org/10.1016/j.aam.2009.12.009
DB - Crossref
KW - Integer partitions
KW - q-Series identities
KW - q-Gauss summation
KW - Little Gollnitz partition theorems
KW - Gollnitz-Gordon partition theorem
KW - Lebesgue identity
ER -
TY - CONF
TI - Direct Transcription Solution of Optimal Control Problems with Control Delays
AU - Betts, John T.
AU - Campbell, Stephen L.
AU - Thompson, Karmethia C.
AU - Simos, Theodore E.
AU - Psihoyios, George
AU - Tsitouras, Ch.
AU - Anastassi, Zacharias
T2 - NUMERICAL ANALYSIS AND APPLIED MATHEMATICS ICNAAM 2011: International Conference on Numerical Analysis and Applied Mathematics
AB - The numerical solution of optimal control problems is important in many areas. Often the models for these problems have delays. Direct transcription is a popular approach for the numerical solution of optimal control problems in industry. However, much less work has been done on the direct transcription solution of optimal control problems with delays. This talk will describe progress and challenges in developing a general purpose industrial grade direct transcription code that can handle problems with delays. Of special interest will be the more challenging case of control delays.
C2 - 2011///
C3 -
DA - 2011///
DO - 10.1063/1.3636665
PB - AIP
UR - http://dx.doi.org/10.1063/1.3636665
DB - Crossref
KW - Optimal control
KW - numerical methods
KW - direct transcription
KW - delays
ER -
TY - JOUR
TI - Expository research papers
AU - Ipsen, I.
T2 - SIAM Review
DA - 2011///
PY - 2011///
VL - 53
IS - 4
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84856706336&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Expository Research Papers
AU - Ipsen, Ilse
T2 - SIAM Review
AB - The two papers in this issue deal with bifurcations and social network analysis. Bifurcation, in its original sense, means division into two branches. In the context of dynamical systems, a bifurcation occurs when a small change in a parameter causes a sudden qualitative change in the solution. Mike Jeffrey and S. J. Hogan study dynamical systems where a state vector x is defined by a system of ordinary differential equations $$\frac{dx}{dt}= f(x,t;\mu)$$ and $\mu$ represents the parameter. Here it is the function f that is responsible for the bifurcations, because f is only piecewise smooth. Piecewise smoothness occurs in applications ranging from engineering and medicine to biology and ecology, often in situations where impact or friction is modeled. Furthermore the authors assume that the discontinuity in f is confined to a smooth manifold of codimension one, the so-called switching manifold, where the solution x remains continuous but may fail to be unique. As a consequence, trajectories of x either cross through the switching manifold or slide along it. If the latter give rise to a bifurcation, then it is, aptly named, a sliding bifurcation. This is a succinct and well-written paper and it makes a number of contributions: first, identifying those points on the switching manifold where switching bifurcations can occur, namely at certain singularities (folds, cusps, saddles, and bowls); second, deriving a complete classification of all one-parameter sliding bifurcations; and third, discovering new sliding bifurcations, which all turn out to be catastrophic. In the second paper, “Comparing Community Structure to Characteristics in Online Collegiate Social Networks,” Amanda Traud, Eric Kelsic, Peter Mucha, and Mason Porter examine how relationships on a social networking site are correlated with demographic traits. In particular, they inspect the complete Facebook pages of five U.S. universities from a single snapshot in September 2005 and ask questions like: If people are friends on Facebook, are they likely to live in the same dormitory, major in the same subject, or have gone to the same high school? Computationally, Facebook users are represented as nodes of a graph, friendships as edges, and social communities as clusters of nodes. Identifying clusters, i.e., community detection, is done with an “unsupervised” algorithm that amounts to optimizing a modularity quality function, which depends only on the edge structure of the graph. This algorithmically computed community must now be compared to communities associated with demographic traits. The authors investigate different similarity measures, based on pair counting, for performing the comparisons. Along the way they face a number of issues: How to display and compare the communities visually? How to compute the correlations accurately and efficiently? What to do about missing data? This is an exciting paper, drawing on tools from graph partitioning, optimization, data clustering, contingency tables, and statistical psychology. It might also be the only paper in a SIAM journal that explains why the social structure at Caltech is different from that of the University of North Carolina.
DA - 2011/1//
PY - 2011/1//
DO - 10.1137/siread000053000003000503000001
VL - 53
IS - 3
SP - 503-503
ER -
TY - JOUR
TI - Expository Research Papers
AU - Ipsen, Ilse
T2 - SIAM Review
AB - You may be concerned that this issue features just a single paper in the Expository Research section. But not to worry—you will get your money's worth. Based on foundations laid by the eminent Austrian-born algebraist Emil Artin (1898–1962) you will be acquainted with improved designs for bread mixers and taffy pullers. Ingredients include topology, dynamical systems, linear algebra, the golden ratio, and Lego toys. The applications considered by Matthew Finn and Jean-Luc Thiffeault in their paper “Topological Optimization of Rod-Stirring Devices” go far beyond food preparation and extend to industrial dough production, and to glass manufacturing where inhomogeneities in molten glass are removed by stirring it with rods. The subject of this paper is the design of efficient devices that stir a fluid thoroughly. When the fluid motion is mainly two-dimensional, as in the case of glass, for example, one can model the fluid as a two-dimensional surface. Instead of using the Stokes equations to describe the fluid motion, the authors adopt a topological approach. They view the fluid as a punctured disk (the punctures being the stirring rods), and the rod motions as mappings of this disk. The mappings associated with efficient practical stirring protocols belong to the so-called pseudo-Anosov category and produce a fluid motion that is related to chaotic dynamical systems. Implementing a pseudo-Anosov mapping requires at least three stirring rods, which is why many taffy pullers have three stirring rods. The authors choose the topological notion of braids to describe the motion protocol of the stirring rods. Mathematical relations derived by Emil Artin identify those groups of braids that can actually be physically realized. In order to estimate how thoroughly a stirring protocol mixes up the fluid, one represents the braids as products of $2\times 2$ matrices, and then determines the spectral radius of the product. For three rods the best stirring protocol has a spectral radius equal to the golden ratio. One must be careful, though, to balance mathematical tractability with practical engineering considerations. Stirring protocols that are optimal from a mathematical point of view are not necessarily so in practice. Part of the reason is that the mathematical approach corresponds to a sequential operation of the stirring rods, while in practice one would want them to work in parallel. The authors devise a parallel motion protocol for stirring rods and present evidence for the optimality of this parallel protocol. This is a marvelous paper, easy to read, accessible, and most enjoyable. To top everything off, the authors built optimal stirring devices with 2 and with 4 stirring rods from Lego toy pieces. How cool is that?
DA - 2011/1//
PY - 2011/1//
DO - 10.1137/siread000053000004000721000001
VL - 53
IS - 4
SP - 721-721
ER -
TY - JOUR
TI - An SDRE-Based Approach for HIV Feedback Control and Control of Thin Film Growth in a CVD Reactor
AU - Banks, H.T.
AU - Beeler, S.C.
AU - Kwon, Hee-Dae
AU - Lewis, B.M.
AU - Toivanen, J.A.
AU - Tran, H.T.
T2 - IFAC Proceedings Volumes
AB - A number of computational methodologies have been proposed in the literature to design and synthesize feedback controls when the plant is modeled by nonlinear dynamical systems. One of the highly promising and rapidly emerging methodologies for designing nonlinear controllers is the state-dependent Riccati equation (SDRE) method in the context of the nonlinear regulator problem. In essence, SDRE mimics the linear quadratic regulator theory by using direct parametrization to rewrite the nonlinear state function as a product of a state-dependent coefficient matrix with the state vector. This paper presents an overview of our successful effort on the application of SDRE for the regulation of the growth of thin films in a high pressure chemical vapor deposition (CVD) and for the development of optimal dynamic multi-drug therapies for human immunodeficiency virus (HIV) infection.
DA - 2011/1//
PY - 2011/1//
DO - 10.3182/20110828-6-it-1002.03412
VL - 44
IS - 1
SP - 9601-9606
J2 - IFAC Proceedings Volumes
LA - en
OP -
SN - 1474-6670
UR - http://dx.doi.org/10.3182/20110828-6-it-1002.03412
DB - Crossref
ER -
TY - CONF
TI - Trust as Dependence: A Logical Approach
AU - Singh, Munindar P.
T2 - International Conference on Autonomous Agents and Multiagent Systems
C2 - 2011/5//
C3 - AAMAS '11: Proceedings of the 10th International Conference on Autonomous Agents and Multiagent Systems
CY - Taipei, Taiwan
DA - 2011/5//
PY - 2011/5/2/
VL - 2
SP - 863–870
PB - IFAAMAS
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899408581&partnerID=MN8TOARS
ER -
TY - CONF
TI - Specifying and Applying Commitment-Based Business Patterns
AU - Chopra, Amit K.
AU - Singh, Munindar P.
T2 - International Conference on Autonomous Agents and Multiagent Systems
C2 - 2011/5//
C3 - AAMAS '11: Proceedings of the 10th International Conference on Autonomous Agents and Multiagent Systems
CY - Taipei, Taiwan
DA - 2011/5//
PY - 2011/5/2/
VL - 1
SP - 475–482
PB - IFAAMAS
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899421820&partnerID=MN8TOARS
ER -
TY - CONF
TI - Information-driven interaction-oriented programming: BSPL, the blindingly simple protocol language
AU - Singh, M.P.
C2 - 2011///
C3 - 10th International Conference on Autonomous Agents and Multiagent Systems 2011, AAMAS 2011
DA - 2011///
VL - 1
SP - 457-464
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899440400&partnerID=MN8TOARS
ER -
TY - CONF
TI - Kokomo: An empirically evaluated methodology for affective applications
AU - Sollenberger, Derek J.
AU - Singh, Munindar P.
T2 - International Conference on Autonomous Agents and MultiAgent Systems
C2 - 2011/5//
C3 - Proceedings of the 10th International Conference on Autonomous Agents and MultiAgent Systems (AAMAS)
CY - Taipei, Taiwan
DA - 2011/5//
PY - 2011/5//
VL - 1
SP - 293–300
PB - IFAAMAS
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899438815&partnerID=MN8TOARS
ER -
TY - BOOK
TI - Formal methods in agent-oriented software engineering
AU - El Fallah-Seghrouchni, A.
AU - Gomez-Sanz, J.J.
AU - Singh, M.P.
DA - 2011///
PY - 2011///
DO - 10.1007/978-3-642-19208-1_15
VL - 6038 LNCS
SE - 213-228
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79952420920&partnerID=MN8TOARS
ER -
TY - CONF
TI - Commitments with regulations: Reasoning about safety and control in REGULA
AU - Marengo, E.
AU - Baldoni, M.
AU - Baroglio, C.
AU - Chopra, A.K.
AU - Patti, V.
AU - Singh, M.P.
C2 - 2011///
C3 - 10th International Conference on Autonomous Agents and Multiagent Systems 2011, AAMAS 2011
DA - 2011///
VL - 1
SP - 433-440
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899444781&partnerID=MN8TOARS
ER -
TY - BOOK
TI - Methodology for engineering affective social applications
AU - Sollenberger, D.J.
AU - Singh, M.P.
AB - Affective applications are becoming increasingly mainstream in entertainment and education. Yet, current techniques for building such applications are limited, and the maintenance and use of affect is in essence handcrafted in each application. The Koko architecture describes middleware that reduces the burden of incorporating affect into applications, thereby enabling developers to concentrate on the functional and creative aspects of their applications. Further, Koko includes a methodology for creating affective social applications, called Koko-ASM. Specifically, it incorporates expressive communicative acts, and uses them to guide the design of an affective social application. With respect to agentoriented software engineering, Koko contributes a methodology that incorporates expressives. The inclusion of expressives, which are largely ignored in conventional approaches, expands the scope of AOSE to affective applications.
DA - 2011///
PY - 2011///
DO - 10.1007/978-3-642-19208-1_7
VL - 6038 LNCS
SE - 97-109
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79952381410&partnerID=MN8TOARS
ER -
TY - CONF
TI - LoST: Local State Transfer: An architectural style for the distributed enactment of business protocols
AU - Singh, M.P.
AB - Local State Transfer (LoST) is a simple, declarative approach for enacting communication protocols. LoST is perfectly distributed and relies only upon the local knowledge of each business partner. It involves a novel treatment of the information bases of protocols, especially in terms of how their parameters are specified. As a result, LoST can capture subtle patterns of interaction that more complex approaches cannot handle well. Further, LoST lends itself to implementations that are robust against unordered and lossy message transmission.
C2 - 2011///
C3 - Proceedings - 2011 IEEE 9th International Conference on Web Services, ICWS 2011
DA - 2011///
DO - 10.1109/ICWS.2011.48
SP - 57-64
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80053159719&partnerID=MN8TOARS
ER -
TY - BOOK
TI - Analyzing contract robustness through a model of commitments
AU - Chopra, A.K.
AU - Oren, N.
AU - Modgil, S.
AU - Desai, N.
AU - Miles, S.
AU - Luck, M.
AU - Singh, M.P.
AB - We address one of the challenges in developing solutions based on multiagent systems for the problems of cross-organizational business processes and commerce generally. Specifically, we study how to gather and analyze requirements embodied within business contracts using the abstractions from multiagent systems. Commerce is driven by business contracts. Each party to a business contract must be assured that the contract is robust, in the sense that it fulfills its goals and avoids undesirable outcomes. However, real-life business contracts tend to be complex and unamenable both to manual scrutiny and domain-independent scientific methods, making it difficult to provide automated support for determining or improving their robustness. As a result, establishing a contract is nontrivial and adds significantly to the transaction costs of conducting business. If the adoption of multiagent systems approaches in supporting business interactions is to be viable, we need to develop appropriate techniques to enable tools to reason about contracts in relation to their robustness. To this end, we propose a powerful approach to assessing the robustness of contracts, and make two main contributions. First, we demonstrate a novel conceptual model for contracts that is based on commitments. Second, we offer a methodology for (i) creating commitment-based models of contracts from textual descriptions, and (ii) evaluating the contract models for robustness. We validate these contributions via a study of real-world contracts.
DA - 2011///
PY - 2011///
DO - 10.1007/978-3-642-22636-6_2
VL - 6788 LNCS
SE - 17-36
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80054108244&partnerID=MN8TOARS
ER -
TY - CONF
TI - Colaba: Collaborative design of cross-organizational processes
AU - Chopra, A.K.
AU - Singh, M.P.
AB - Cross-organizational processes naturally involve multiple stakeholders with distinct business interests. Yet, current process modeling approaches are conceptually centralized. This paper develops Colaba, a novel approach for the design of a cross-organizational process. Colaba naturally accommodates the requirements of multiple stakeholders. It is realized as a tool and methodology that uses and maintains a repository of business protocols, each describing a business function to the desired level of nuance. Design in Colaba is thus simply a matter of selecting, refining, extending, and composing protocols. Colaba is based on the concepts of Issue-Based Information Systems. It naturally supports stakeholders proposing process models, raising issues about them, and evaluating alternative proposals. Colaba contributes argumentation primitives and a representation relevant to business processes that accommodates the diverse perspectives of the roles in a protocol. This paper includes an evaluation of Colaba via a case study.
C2 - 2011///
C3 - 2011 Workshop on Requirements Engineering for Systems, Services and Systems-of-Systems, RESS 2011 - Workshop Co-located with the 19th IEEE International Requirements Engineering Conference
DA - 2011///
DO - 10.1109/RESS.2011.6043928
SP - 36-43
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80055038648&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Patient specific modeling of cardiovascular and respiratory dynamics during hypercapnia
AU - Ellwein, L M
AU - Pope, S R
AU - Xie, A
AU - Batzel, J
AU - Kelley, C T
AU - Olufsen, M S
T2 - Mathematical Biosciences
DA - 2011///
PY - 2011///
VL - 241
IS - 1
SP - 56--74
ER -
TY - JOUR
TI - Finding A Stable Solution of A System of Nonlinear Equations
AU - Kelley, C T
AU - Qi, L
AU - Tong, X
AU - Yin, H
T2 - J. Indus. Manag. Opt.
DA - 2011///
PY - 2011///
VL - 7
SP - 497-521
ER -
TY - JOUR
TI - Users' Guide for imfil
AU - Kelley, C T
DA - 2011///
PY - 2011///
ER -
TY - CONF
TI - Application of a Modified Nelder-Mead Algorithm for calibrating RF Analog Integrated Circuits
AU - Wyers, E.J.
AU - Steer, M.B.
AU - Kelley, C.T.
AU - Franzon, P.D.
C2 - 2011///
C3 - Proceedings GOMACTech'11
DA - 2011///
SP - 545–548
ER -
TY - BOOK
TI - Implicit Filtering
AU - Kelley, C T
DA - 2011///
PY - 2011///
PB - SIAM
ER -
TY - JOUR
TI - Nonlinear Least Squares Problems and Subset Selection
AU - Ipsen, I C F
AU - Kelley, C T
AU - Pope, S R
T2 - SIAM J. Numer. Anal.
DA - 2011///
PY - 2011///
VL - 49
SP - 1244-1266
ER -
TY - JOUR
TI - Expository Research Papers
AU - Ipsen, Ilse
T2 - SIAM Review
AB - The two papers in this issue are concerned with fair division and with approximation of functions. “Divide-and-Conquer: A Proportional, Minimal-Envy Cake-Cutting Algorithm,” by Steven Brams, Michael Jones, and Christian Klamler, has nothing to do with wedding cakes or Food Network Challenges. Instead it deals with the mathematical problem of proportional division, which often arises in social science applications. Let us illustrate the cake-cutting paradigm with the divide-and-choose algorithm for two players. Suppose you and I are to cut a cake, so that each of us gets half of the cake, where “half” is interpreted according to our preferences. Suppose you like chocolate and prefer a piece with at least half of all the chocolate decoration. I, on the other hand, like marzipan and prefer a piece with at least half of all the marzipan decoration. In the divide-and-choose algorithm, I start by cutting the cake into two pieces, so that each piece contains the same amount of marzipan. Then you pick the piece with the most chocolate. This is a proportional and envy-free division of the cake. The division is proportional because each of us gets at least half of what we want (chocolate in your case, marzipan in mine), and it is envy-free because none of us would want the other's piece. Mathematically, one expresses the preference for chocolate or marzipan in terms of a probability density function. For n players the situation is much more complicated. The authors propose a divide-and-conquer algorithm that requires only the minimal number of $n-1$ cuts. Although the algorithm is not envy-free, it does minimize the maximal number of players that any player can envy. The algorithm is also simple and easy to implement. Now for the second paper. Back in 1901 the German mathematician Carl Runge showed that polynomial interpolation of a function at n equally spaced points in the interval $[-1,1]$ can produce interpolants that fail to converge as $n\rightarrow\infty$, because they exhibit large-amplitude oscillations near the interval endpoints. In their paper “Impossibility of Fast Stable Approximation of Analytic Functions from Equispaced Samples,” Rodrigo Platte, Lloyd Trefethen, and Arno Kuijlaars look at the situation in a more general setting, and with finite precision computation in the back of their minds. Now the approximants do not have to be interpolating polynomials. They can be much more general. All that is required is that an approximant $\phi_n(f)$ depend on f at the n equally spaced grid points in $[-1,1]$, but nowhere else. The question is: How can perturbations in f affect the convergence of the approximant $\phi_n(f)$ in the worst case? To answer this question, the authors introduce a condition number $\kappa_n$ that measures how sensitive $\phi_n(f)$ can be to changes in f. You can think of $\kappa_n$ as sort of a Lipschitz constant for $\phi_n$. The main result is: If the approximants converge exponentially fast, in the sense that $\|f-\phi_n(f)\|\sim \sigma^n$ for some $\sigma<1$, then $\kappa_n\sim C^n$ for some $C>1$. This means, in the worst case, exponentially fast convergence comes at the price of exponential ill-conditioning. The authors also identify connections with potential theory, matrix iterations in the form of Krylov space methods, and quadrature formulae.
DA - 2011/1//
PY - 2011/1//
DO - 10.1137/siread000053000002000289000001
VL - 53
IS - 2
SP - 289-289
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79957451081&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Expository Research Papers
AU - Ipsen, Ilse
T2 - SIAM Review
AB - The two papers in this issue are of the analytic kind. The first one deals with symbol calculus, and the second one with compressed sensing. In their paper “Discrete Symbol Calculus,” Laurent Demanet and Lexing Ying propose efficient representations for functions of elliptic operators. The idea is to replace the symbol of an operator matrix A by a low-rank approximation. Then one can derive an efficient representation for $f(A)$, where f is a function like inverse, square root, or exponential. The low-rank approximations are constructed from rational Chebyshev interpolants, and also from hierarchical spline interpolants. The authors analyze how many terms are required for a low-rank approximation of specified accuracy, and they present numerical experiments. This appears to be an original and promising approach for reflection seismology and other areas of wave propagation. Compressed sensing is one of mathematics' hot topics. And it has already made contributions to signal processing: Compressed sensing can reduce the time for an MRI scan by a factor of 7. This is remarkable when you imagine that a small child may be able to hold still for 1 minute, but rarely for an eternity of 7. So what is compressed sensing? Suppose we want to determine (“measure”) all N elements of an unknown vector x. The straightforward way would be to perform N inner products with canonical vectors, with each canonical vector being responsible for one element of x. If x is sparse with only k nonzero elements, and we know the positions of these nonzero elements, then k inner products suffice to measure x. But what if we don't know the positions of the k nonzero elements? Can we still measure x with about k inner products? Look to compressed sensing for answers, and you'll be advised as follows: Perform the inner products in parallel, by means of a matrix vector multiplication $Ax$. However, for the rows of A don't choose canonical vectors, but instead choose, say, random vectors. The resulting algorithm for measuring x consists of two steps: The first (“encoding”) step determines a vector y from the matrix vector product $y=Ax$. There upon A and y are fed as constraints to the second (“decoding”) step, which recovers x as the solution of the $\ell_1$ minimization problem $\min_z{\|z\|_1}$ subject to the constraint $Az=y$. The performance of A in recovering x can be quantified from a RIP constant, where “RIP” stands for “restricted isometry property.” The RIP constant of A indicates how much A can deviate from behaving like an isometry when applied to vectors with k nonzero elements. More precisely, the RIP constant indicates by how much A can distort the two norm of a vector with k nonzero elements. RIP constants are the topic of the second paper, “Compressed Sensing: How Sharp Is the Restricted Isometry Property?” by Jeffrey Blanchard, Coralia Cartis, and Jared Tanner. They present tight bounds on RIP constants, and they introduce the framework of proportional growth arithmetic in order to compare RIP bounds to two alternative performance metrics: polytope analysis and geometric functional analysis techniques. This is an exciting paper and an exciting area, combining tools from matrix theory, probability, and functional analysis!
DA - 2011/1//
PY - 2011/1//
DO - 10.1137/siread000053000001000069000001
VL - 53
IS - 1
SP - 69-69
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84856703956&partnerID=MN8TOARS
ER -
TY -
ER -
TY - CONF
TI - Maximally reduced observers for linear time varying DAEs
AU - Bobinyec, Karen
AU - Campbell, Stephen L.
AU - Kunkel, Peter
T2 - Control (MSC)
AB - The problem of observer design for descriptor systems, or systems of differential algebraic equations (DAEs) as they are also known, has been studied in the linear time invariant case. However, those studies do not readily extend to general linear time varying descriptor systems. Recently there have been new theoretical results and algorithms for computing completions of DAEs. In this paper we examine the application of these ideas to the computation of reduced order observers for linear time invariant and linear time varying DAEs.
C2 - 2011/9//
C3 - 2011 IEEE International Symposium on Computer-Aided Control System Design (CACSD)
DA - 2011/9//
DO - 10.1109/cacsd.2011.6044570
PB - IEEE
SN - 9781457710667
UR - http://dx.doi.org/10.1109/cacsd.2011.6044570
DB - Crossref
ER -
TY - CONF
TI - Optimal control software for constrained nonlinear systems with delays
AU - Betts, John T.
AU - Campbell, Stephen L.
AU - Thompson, Karmethia C.
T2 - Control (MSC)
AB - The numerical solution of optimal control problems is important in a variety of industries. One of the popular methods for complex problems is direct transcription. Direct transcription does not rely on the necessary conditions and it is easy to incorporate a wide variety of constraints on both controls and states. Optimal control problems can often involve delays in the state or the control or both. While some numerical methods exist for some optimal control problems with delays they are not direct transcription methods. This paper reports on progress in developing a general purpose industrial grade software package to numerically solve complex optimal control problems with delays and state and control constraints using direct transcription.
C2 - 2011/9//
C3 - 2011 IEEE International Symposium on Computer-Aided Control System Design (CACSD)
DA - 2011/9//
DO - 10.1109/cacsd.2011.6044560
PB - IEEE
SN - 9781457710667
UR - http://dx.doi.org/10.1109/cacsd.2011.6044560
DB - Crossref
ER -
TY - JOUR
TI - Active incipient fault detection in continuous time systems with multiple simultaneous faults
AU - Stephen, Campbell
AU - Martene, Fair
T2 - Numerical Algebra, Control and Optimization
AB - The problem of detecting small parameter variations in linear uncertain systems due to incipient faults, with the possibility of injecting an input signal to enhance detection, is considered. Most studies assume that there is only one fault developing. Recently an active approach for two or more simultaneous faults has been introduced for the discrete time case. In this paper we extend this approach to the continuous time case. A computational method for the construction of an input signal for achieving guaranteed detection with specified precision is presented. The method is an extension of a multi-model approach used for the construction of auxiliary signals for failure detection, however, new technical issues must be addressed.
DA - 2011/6//
PY - 2011/6//
DO - 10.3934/naco.2011.1.211
VL - 1
IS - 2
SP - 211-224
J2 - NACO
LA - en
OP -
SN - 2155-3289
UR - http://dx.doi.org/10.3934/naco.2011.1.211
DB - Crossref
KW - Fault detection
KW - numerical methods
ER -
TY - CONF
TI - Direct optimization determination of auxiliary test signals for linear problems with model uncertainty
AU - Andjelkovic, Ivan
AU - Campbell, Stephen L.
T2 - 2011 50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC 2011)
AB - Recently there has been increased interest in active approaches for fault detection which use auxiliary test signals. Theory and algorithms have been presented in the literature for the design of fault detection signals for linear systems with model uncertainty. These approaches cannot solve many problems with constraints. This paper gives the first direct optimization formulation of the more general constrained problem. The use of a direct optimization formulation allows the solution of problems not possible by the original algorithms such as problems with input and state constraints. Computational examples are given both to illustrate the theory and to discuss computational issues.
C2 - 2011/12//
C3 - IEEE Conference on Decision and Control and European Control Conference
DA - 2011/12//
DO - 10.1109/cdc.2011.6160186
PB - IEEE
SN - 9781612848013 9781612848006 9781467304573 9781612847993
UR - http://dx.doi.org/10.1109/cdc.2011.6160186
DB - Crossref
ER -
TY - CONF
TI - Full order observers for linear DAEs
AU - Bobinyec, Karen
AU - Campbell, Stephen L.
AU - Kunkel, Peter
T2 - 2011 50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC 2011)
AB - Observer design for descriptor systems, or systems of differential algebraic equations (DAEs) as they are also known, is well studied in the linear time invariant (LTI) case. However, those studies do not readily extend to general linear time varying (LTV) or nonlinear descriptor systems. This paper presents an alternative approach for observer design that not only works for the LTI case but also shows great potential for the design of observers for general LTV descriptor systems.
C2 - 2011/12//
C3 - IEEE Conference on Decision and Control and European Control Conference
DA - 2011/12//
DO - 10.1109/cdc.2011.6160215
PB - IEEE
SN - 9781612848013 9781612848006 9781467304573 9781612847993
UR - http://dx.doi.org/10.1109/cdc.2011.6160215
DB - Crossref
ER -
TY - JOUR
TI - QTL Mapping for Days to Flowering under Drought Condition in Rice (Oryza sativa L.) Genome
AU - Chakraborty, Supriyo
AU - Zeng, Zhao Bang
T2 - Notulae Botanicae Horti Agrobotanici Cluj-Napoca
AB - QTL for days to flowering in rice under drought condition were mapped using a DH population derived from a cross between a deep-rooted upland adapted japonica genotype CT9993-5-10-1-M and a lowland adapted shallow-rooted moderately drought tolerant indica genotype IR62266-42-6-2. QTL mapping was performed following three different mapping models viz. simple (SIM), composite (CIM) and multiple mapping model (MIM) using WinQTL Cartographer version 2.5.006. SIM located 12 QTL for days to flowering spread over nine chromosomes whereas CIM and MIM each located 5 QTL with a threshold LOD score of 2.5. A comparison of the QTL detected by three different models identified five QTL that were common across at least two models for days to flowering. In MIM analysis, the detected QTL (qHD-1-b) between flanking markers (RG109 – ME1014) located on chromosome 1 recorded positive effect (1.4090) but the remaining four QTL had negative effect. The QTL (qHD-3-a) detected between flanking markers (RG104 – RG409) by both MIM and SIM in the present study was also reported earlier as linked with the marker RG104. The five common QTL detected by at least two models could be considered as stable QTL for days to flowering under drought and might be of practical use in marker assisted selection.
DA - 2011/5/30/
PY - 2011/5/30/
DO - 10.15835/nbha3915610
VL - 39
IS - 1
SP - 58
J2 - Not Bot Hort Agrobot Cluj
OP -
SN - 1842-4309 0255-965X
UR - http://dx.doi.org/10.15835/nbha3915610
DB - Crossref
ER -
TY - CONF
TI - Direct transcription solution of optimal control problems with delays
AU - Betts, J.T.
AU - Campbell, S.L.
AU - Thompson, Karmethia
C2 - 2011///
C3 - Numerical Analysis and Applied Mathematics ICNAAM2011 AIP Conf. Proc.
DA - 2011///
VL - 1389
SP - 38–41
ER -
TY - CONF
TI - Integrating Computing into Thermodynamics: Lessons Learned
AU - Pasquinelli, M.
AU - Joines, J.A.
T2 - American Society for Engineering Education International Conference
C2 - 2011///
C3 - 2011 ASEE Annual Conference & Exposition
DA - 2011///
SP - 22-901
ER -
TY - CONF
TI - A content freshness enhancement with infrastructures in mobile opportunistic networks
AU - Ban, D.
AU - Devetsikiotis, M.
AB - In mobile opportunistic networks, we investigate the effect of infrastructures on content update process. In the network, an information provider continuously generates a time-sensitive content (e.g., news, twits or military commands) whose freshness decreases with time. This information is propagated to users throughout opportunistic contacts. Users prefer to have the more recently generated (i.e., up-to-date) content. In that, they utilize a content age to compare their freshness and share only the smaller age content when an opportunistic contact occurs.
C2 - 2011///
C3 - 2011 - Milcom 2011 Military Communications Conference
DA - 2011///
DO - 10.1109/milcom.2011.6127811
SP - 997-1002
ER -
TY - CONF
TI - on distribution and limits of information dissemination latency and speed in mobile cognitive radio networks
AU - Sun, L.
AU - Wang, Wenye
AB - Dissemination latency and speed are central to the applications of cognitive radio networks, which have become an important component of current communication infrastructure. In this paper, we investigate the distributions and limits of information dissemination latency and speed in a cognitive radio network where licensed users (primary users) are static and cognitive radio users (secondary users) are mobile. We show that the dissemination latency depends on the stationary spatial distribution and mobility capability α (characterizing the region that a mobile secondary user can reach) of secondary users. Given any stationary spatial distribution, we find that there exists a critical value on α, below which the latency and speed are heavy-tailed and above which the right tails of their distribution are bounded by Gamma random variables. We further show that as the network grows to infinity, the latency asymptotically scales linearly with the “distance” (characterized by transmission hops or Euclidean distance) between the source and the destination. Our results are validated through simulations.
C2 - 2011///
C3 - 2011 proceedings ieee infocom
DA - 2011///
DO - 10.1109/infcom.2011.5935069
SP - 246–250
ER -
TY - CONF
TI - From jammer to gambler: Modeling and detection of jamming attacks against time-critical traffic
AU - Lu, Z.
AU - Wang, Wenye
AU - Wang, C.
AB - Time-critical wireless applications in emerging network systems, such as e-healthcare and smart grids, have been drawing increasing attention in both industry and academia. The broadcast nature of wireless channels unavoidably exposes such applications to jamming attacks. However, existing methods to characterize and detect jamming attacks cannot be applied directly to time-critical networks, whose communication traffic model differs from conventional models. In this paper, we aim at modeling and detecting jamming attacks against time-critical traffic. We introduce a new metric, message invalidation ratio, to quantify the performance of time-critical applications. A key insight that leads to our modeling is that the behavior of a jammer who attempts to disrupt the delivery of a time-critical message can be exactly mapped to the behavior of a gambler who tends to win a gambling game. We show via the gambling-based modeling and real-time experiments that there in general exists a phase transition phenomenon for a time-critical application under jamming attacks: as the probability that a packet is jammed increases from 0 to 1, the message invalidation ratio first increases slightly (even negligibly), then increases dramatically to 1. Based on analytical and experimental results, we further design and implement the JADE (Jamming Attack Detection based on Estimation) system to achieve efficient and robust jamming detection for time-critical wireless networks.
C2 - 2011///
C3 - 2011 proceedings ieee infocom
DA - 2011///
DO - 10.1109/infcom.2011.5934989
SP - 1871–1879
ER -
TY - CONF
TI - Communication genres: Integrating communication into the software engineering curriculum
AU - Carter, M.
AU - Vouk, M.
AU - Gannod, G. C.
AU - Burge, J. E.
AU - Anderson, P. V.
AU - Hoffman, M. E.
AB - One way to improve the communication abilities of new software engineering graduates in the workplace is to integrate communication more effectively in the software engineering curriculum. But faculty typically conceive of communication as outside their realm of expertise. Based on the results of an NSF-funded project, we use theories of situated learning and genre to make the case that communication is integral to software engineering and that faculty are in the best position to guide students in becoming better communicators in the field. We identify software engineering genres and show how those genres may be used to integrate communication in the classroom and throughout the curriculum.
C2 - 2011///
C3 - 2011 24th IEEE-CS Conference on Software Engineering Education and Training (CSEET)
DA - 2011///
DO - 10.1109/cseet.2011.5876091
SP - 21-30
ER -
TY - JOUR
TI - A new choice rule for regularization parameters in Tikhonov regularization
AU - Ito, Kazufumi
AU - Jin, Bangti
AU - Zou, Jun
T2 - APPLICABLE ANALYSIS
AB - This article proposes and analyses a novel heuristic rule for choosing regularization parameters in Tikhonov regularization for inverse problems. The existence of solutions to the regularization parameter equation is shown, and a variational characterization of the inverse solution is provided. Some a posteriori error estimates of the approximate solutions to the inverse problem are also established. An iterative algorithm is suggested for the efficient numerical realization of the new choice rule, which is shown to have a practically desirable monotone convergence. Numerical experiments for both mildly and severely ill-posed benchmark inverse problems with various regularizing functionals of Tikhonov type, e.g. L 2–L 2 with constraints, L 2–l1 and L 1–TV, are presented to demonstrate its effectiveness, and compared with the quasi-optimality criterion.
DA - 2011///
PY - 2011///
DO - 10.1080/00036811.2010.541450
VL - 90
IS - 10
SP - 1521-1544
SN - 1563-504X
KW - parameter choice
KW - a posteriori error estimate
KW - Tikhonov regularization
ER -
TY - JOUR
TI - A metamodeling approach for cross-layer optimization: A framework and application to Voice over WiFi
AU - Papapanagiotou, Ioannis
AU - Granelli, Fabrizio
AU - Kliazovich, Dzmitry
AU - Devetsikiotis, Michael
T2 - SIMULATION MODELLING PRACTICE AND THEORY
AB - Cross-layer design has been proposed to optimize the performance of networks by exploiting the interrelations among parameters and procedures at different levels of the protocol stack. This paper introduces a quantitative framework for the study of cross-layer interactions, which enables design engineers to analyze and quantify interlayer dependencies and to identify the optimal operating point of the system, by using network economic theory principles. The framework is then used for performance optimization of a single-cell Voice over WiFi (VoWiFi) system. Insights gained from the considered scenario enable us to define a novel cross-layer Call Admission Control (CAC) scheme. The multistage CAC takes into account Quality of Service (QoS) criteria, which provide satisfaction to the end user, as well as revenue criteria that maximize the possible profit of the WiFi provider.
DA - 2011/10//
PY - 2011/10//
DO - 10.1016/j.simpat.2011.06.005
VL - 19
IS - 9
SP - 2117-2129
SN - 1878-1462
KW - Cross-layer design
KW - Metamodeling
KW - Call Admission Control (CAC)
KW - VoWiFi
ER -
TY - CONF
TI - Tutorial on the simulation of healthcare systems
AU - Roberts, S. D.
AB - For a variety of reasons, simulation has enjoyed widespread application in health care and health care delivery systems. Although the dominant modeling methodology is discrete event simulation, numerous studies employ system dynamics, agent-based simulation, and hybrid/combined methods. Software has been increasingly adapted to health care through enhanced visualizations and modeling. Virtually every health care environment has been studied using simulation including hospitals, extended care, rehabilitation, specialty care, long-term care, public health, among others. Frequent problems are patient flow, staffing, works schedules, facilities capacity and design, admissions/scheduling, appointments, logistics, and planning. Health care problems are especially complicated by the fact that “people serve people,” meaning people are both the customer and the supply. The customers arrive through a complex decision process that produces uncertain demand. The response is an even more complex organization of health care resources, each of which play a distinctive and overlapping role, providing a unique simulation challenge.
C2 - 2011///
C3 - Proceedings of the 2011 winter simulation conference (wsc)
DA - 2011///
DO - 10.1109/wsc.2011.6147860
SP - 1403-1414
ER -
TY - JOUR
TI - Information sharing in capacity constrained supply chains under lost sales
AU - Davis, Lauren B.
AU - King, Russell E.
AU - Hodgson, Thom J.
AU - Wei, Wenbin
T2 - INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH
AB - We present a modelling approach for quantifying the value of information in supply chains using Markov decision processes (MDP). The case where information sharing occurs is modelled using a completely observable MDP. A restricted observation MDP is used to model the case where no information sharing occurs. We illustrate the use of this framework on a two-stage capacity-constrained supply chain consisting of a supplier and a retailer. We quantify the value of information sharing in this setting and construct several performance measures to identify the benefits to both the retailer and supplier as a result of the information sharing partnership.
DA - 2011///
PY - 2011///
DO - 10.1080/00207543.2010.535037
VL - 49
IS - 24
SP - 7469-7491
SN - 1366-588X
KW - Markov decision process
KW - supply chain information sharing
ER -
TY - CONF
TI - Analysis of response time percentile service level agreements in SOA-based applications
AU - Boloor, K.
AU - Chirkova, R.
AU - Salo, T.
AU - Viniotis, Y.
AB - A large number of enterprise, web-based, distributed software applications are designed on Service Oriented Architecture (SOA) principles and hosted in large scale datacenters managed by cloud providers. Typically, Service Level Agreements (SLAs) are negotiated between the consumers of the cloud platform services and the cloud provider. In this work, we consider SLAs that involve percentiles of response times as part of the performance metrics; the SLAs stipulate that a penalty be charged to the cloud provider if the SLA targets are not met. The main motivation for considering such SLAs is their potential for price differentiation. We focus our analysis on the effects the penalty function has on the achieved response time percentiles. In particular, we analyze the effect of three commonly deployed choices (linear, exponential or step-wise functions) to relate the penalty charged and the achieved percentile. This analysis is NP-hard, so we employ a heuristic algorithm that is based on simulated annealing. Our results indicate that the linear penalty charging function is "best'' in the sense that it maximizes the achieved response time percentiles.
C2 - 2011///
C3 - 2011 ieee global telecommunications conference (globecom 2011)
DA - 2011///
DO - 10.1109/glocom.2011.6133866
ER -
TY - CONF
TI - On the access time in mobile hybrid networks
AU - Zheng, H. Y.
AU - Wang, Wenye
AB - This paper investigates the access time of mobile nodes to infrastructure networks in Mobile Hybrid Networks (MHNs), e.g., sensor-actuator networks, where mobile nodes move around the coexisting infrastructure networks. In such networks, mobile nodes may relay data packets in a hop-by-hop fashion, and eventually deliver packets to the wired networks. Our objective is to study the lower bound of the access time, which implies the minimum time to deliver data packets from low-speed, unreliable wireless networks to the high-speed, reliable infrastructure network. In particular, we propose a theoretical framework to analyze the packet propagation speed in MHNs, and to show that there is a unified lower bound on the access time regardless of data forwarding schemes. When wireless nodes move at an average speed of v and variance σ ^{2} towards an AP, and their density λ is small (e.g., the network is sparse and surely disconnected), we prove that the expected access time is lower bounded by (L _{b} (0)-r) ^{2} /σ ^{2} packet mobility is unbiased and L _{b} (0)-r/v for the biased case, where L _{b} (0) is the distance from the source node to the nearest access point. Here, packet mobility is the mobility of a packet due to both node mobility and data transmissions. We further propose a routing scheme to achieve such theoretical bounds.
C2 - 2011///
C3 - 2011 ieee global telecommunications conference (globecom 2011)
DA - 2011///
DO - 10.1109/glocom.2011.6133498
ER -
TY - CONF
TI - On optimal tiered structures for network service bundles
AU - Lv, Q.
AU - Rouskas, G. N.
AB - Network operators offer a variety of tiered services in which users may select only from a small set of tiers which offer progressively higher levels of service. Service bundling, whereby several services are combined together and sold as a single package, is also common in the telecommunications market. We consider the problem of determining optimal tiering structures for service bundles using tools from economics and utility theory. Our work provides insight into the selection and pricing of Internet tiered services.
C2 - 2011///
C3 - 2011 ieee global telecommunications conference (globecom 2011)
DA - 2011///
DO - 10.1109/glocom.2011.6133598
ER -
TY - CONF
TI - On network performance evaluation toward the smart grid: A case study of DNP3 over TCP/IP
AU - Lu, X.
AU - Lu, Z.
AU - Wang, Wenye
AU - Ma, J. F.
AB - The smart grid is the next-generation power system that incorporates power infrastructures with information technologies. In the smart grid, power devices are interconnected to support a variety of intelligent mechanisms, such as relay protection and demand response. To enable such mechanisms, messages must be delivered in a timely manner via network protocols. A cost-efficient and backward-compatible way for smart grid protocol design is to migrate current protocols in supervisory control and data acquisition (SCADA) systems to the smart grid. However, an open question is whether the performance of SCADA protocols can meet the timing requirements of smart grid applications. To address this issue, we establish a micro smart grid, Green Hub, to measure the delay performance of a predominant SCADA protocol, distributed network protocol 3.0 (DNP3) over TCP/IP. Our results show that although DNP3 over TCP/IP is widely considered as a smart grid communication protocol, it cannot be used in applications with delay constraints smaller than 16ms in Green Hub, such as relay protection. In addition, since DNP3 provides reliability mechanisms similar to TCP, we identify that such an overlapped design induces 50%-80% of the processing delay in embedded power devices. Our results indicate that DNP3 over TCP/IP can be further optimized in terms of delay efficiency, and a lightweight communication protocol is essential for time-critical smart grid applications.
C2 - 2011///
C3 - 2011 ieee global telecommunications conference (globecom 2011)
DA - 2011///
DO - 10.1109/glocom.2011.6134406
ER -
TY - JOUR
TI - NC State's Supply Chain Resource Cooperative Educates in the Real World
AU - Handfield, Robert B.
AU - Edwards, Steven A.
AU - Stonebraker, Jeffrey S.
T2 - INTERFACES
AB - North Carolina State University's Supply Chain Resource Cooperative (SCRC) is a unique university-industry initiative that provides MBA and undergraduate students with opportunities to apply supply chain (SC) theory and concepts to field-based projects over a semester. We integrate field-based student course projects with real problems that companies are facing. The projects are led by SCRC directors, faculty at the Poole College of Management, and SC managers that financially support the SCRC. The SCRC focuses on improving the caliber of students entering the SC management profession. It accomplishes this by bringing the classroom into industry and involving students in finding viable solutions to real business problems, thus facilitating interactions between students and companies. Since 2000, 1,251 students have completed 331 projects with 39 companies. The SCRC is a self-funded small business that is supported by donor companies. Its organizational structure enables us to develop and maintain long-term relationships with donor companies, which are critical for a successful student-based outreach initiative with industry. In this paper, we describe the SCRC's evolution and benefits, and provide insights that may help other institutions interested in establishing similar organizations.
DA - 2011///
PY - 2011///
DO - 10.1287/inte.1110.0584
VL - 41
IS - 6
SP - 548-563
SN - 1526-551X
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-83455262975&partnerID=MN8TOARS
KW - education
KW - field-based student projects
KW - supply chain applications
ER -
TY - CONF
TI - Intermittently connected vehicle-to-vehicle networks: Detection and analysis
AU - Li, Y. J.
AU - Zhao, M.
AU - Wang, Wenye
AB - Vehicular Adhoc Networks (VANETs) are dedicated to improve the safety and efficiency of transportation systems through vehicle to vehicle or vehicle to road side communications. VANETs exhibit dynamic topology and intermittent connectivity due to high vehicle mobility. These distinguished features declare a challenging question: how to detect on the fly vehicular networks such that we can explore mobility-assisted message dissemination and topology control in VANETs. As being closely related to network dynamics, vehicle mobility could be explored to uncover network structure. In this paper, we have observed that mobility of vehicle, rather than being random, shows temporal locality (i.e., frequently visiting several communities like home and office), and spatial locality (i.e., velocity constrained by road layout and nearby vehicles). We first examine temporal locality using a campus trace, then measure temporal locality similarity between two vehicles based on the relative entropy of their location preferences. By further incorporating spatial locality similarity, we introduce a new metric, namely dual locality ratio (DLR), which represents the mobility correlation of vehicles. Simulation results show that DLR can effectively identify dynamic vehicular network structures. We also demonstrate applications of DLR for improving performances of data forwarding and clustering in vehicle-to-vehicle networks.
C2 - 2011///
C3 - 2011 ieee global telecommunications conference (globecom 2011)
DA - 2011///
DO - 10.1109/glocom.2011.6134395
ER -
TY - CONF
TI - Aggregated-DAG Scheduling for Job Flow Maximization in Heterogeneous Cloud Computing
AU - Saovapakhiran, B.
AU - Michailidis, G.
AU - Devetsikiotis, M.
AB - Heterogeneous computing platforms such as Grid and Cloud computing are becoming prevalent and available online. As a result, resource management in these platforms is fundamentally critical to their global performance. Under the assumption of jobs comprised of subtasks forming DAG jobs, we focus on how to increase utilization and achieve near-optimal throughput performance on heterogeneous platforms. Our analysis and proposed algorithm are analytically derived and establish that, by aggregating multiple jobs using good scheduling, a near-optimal throughput can be achieved. Consequently, its limit is asymptotically converging to a certain value and can be written in the form of the service time of subtasks. Furthermore, our analysis shows how to explicitly compute the optimal throughput of computing systems, an important task for such a complex scheduling problem. In addition, we derive a simple super-job scheduling and show that its performance in term of throughput is better than the well-known Heterogeneous Earliest-Finish-Time (HEFT) algorithm.
C2 - 2011///
C3 - 2011 ieee global telecommunications conference (globecom 2011)
DA - 2011///
DO - 10.1109/glocom.2011.6133611
ER -
TY - JOUR
TI - A survey on the communication architectures in smart grid
AU - Wang, Wenye
AU - Xu, Yi
AU - Khanna, Mohit
T2 - COMPUTER NETWORKS
AB - The next-generation electric power systems (smart grid) are studied intensively as a promising solution for energy crisis. One important feature of the smart grid is the integration of high-speed, reliable and secure data communication networks to manage the complex power systems effectively and intelligently. We provide in this paper a comprehensive survey on the communication architectures in the power systems, including the communication network compositions, technologies, functions, requirements, and research challenges. As these communication networks are responsible for delivering power system related messages, we discuss specifically the network implementation considerations and challenges in the power system settings. This survey attempts to summarize the current state of research efforts in the communication networks of smart grid, which may help us identify the research problems in the continued studies.
DA - 2011/10/27/
PY - 2011/10/27/
DO - 10.1016/j.comnet.2011.07.010
VL - 55
IS - 15
SP - 3604-3629
SN - 1872-7069
KW - Smart grid
KW - Power communications
KW - Communication networks
KW - Communication protocols
KW - Grid standards
ER -
TY - JOUR
TI - A simple novel approach to valuing risky zero coupon bond in a markov regime switching economy
AU - Deshpande, A.
T2 - Methodology and Computing in Applied Probability
DA - 2011///
PY - 2011///
VL - 13
IS - 4
SP - 783-800
ER -
TY - JOUR
TI - Enteric Microbiome Metabolites Correlate with Response to Simvastatin Treatment
AU - Kaddurah-Daouk, Rima
AU - Baillie, Rebecca A.
AU - Zhu, Hongjie
AU - Zeng, Zhao-Bang
AU - Wiest, Michelle M.
AU - Nguyen, Uyen Thao
AU - Wojnoonski, Katie
AU - Watkins, Steven M.
AU - Trupp, Miles
AU - Krauss, Ronald M.
T2 - PLOS ONE
AB - Although statins are widely prescribed medications, there remains considerable variability in therapeutic response. Genetics can explain only part of this variability. Metabolomics is a global biochemical approach that provides powerful tools for mapping pathways implicated in disease and in response to treatment. Metabolomics captures net interactions between genome, microbiome and the environment. In this study, we used a targeted GC-MS metabolomics platform to measure a panel of metabolites within cholesterol synthesis, dietary sterol absorption, and bile acid formation to determine metabolite signatures that may predict variation in statin LDL-C lowering efficacy. Measurements were performed in two subsets of the total study population in the Cholesterol and Pharmacogenetics (CAP) study: Full Range of Response (FR), and Good and Poor Responders (GPR) were 100 individuals randomly selected from across the entire range of LDL-C responses in CAP. GPR were 48 individuals, 24 each from the top and bottom 10% of the LDL-C response distribution matched for body mass index, race, and gender. We identified three secondary, bacterial-derived bile acids that contribute to predicting the magnitude of statin-induced LDL-C lowering in good responders. Bile acids and statins share transporters in the liver and intestine; we observed that increased plasma concentration of simvastatin positively correlates with higher levels of several secondary bile acids. Genetic analysis of these subjects identified associations between levels of seven bile acids and a single nucleotide polymorphism (SNP), rs4149056, in the gene encoding the organic anion transporter SLCO1B1. These findings, along with recently published results that the gut microbiome plays an important role in cardiovascular disease, indicate that interactions between genome, gut microbiome and environmental influences should be considered in the study and management of cardiovascular disease. Metabolic profiles could provide valuable information about treatment outcomes and could contribute to a more personalized approach to therapy.
DA - 2011/10/13/
PY - 2011/10/13/
DO - 10.1371/journal.pone.0025482
VL - 6
IS - 10
SP -
SN - 1932-6203
ER -
TY - JOUR
TI - Application of Proper Orthogonal Decomposition (POD) to inverse problems in saturated groundwater flow
AU - Winton, Corey
AU - Pettway, Jackie
AU - Kelley, C. T.
AU - Howington, Stacy
AU - Eslinger, Owen J.
T2 - ADVANCES IN WATER RESOURCES
AB - We develop a new Proper Orthogonal Decomposition (POD) reduced order model for saturated groundwater flow, and apply that model to an inverse problem for the hydraulic conductivity field. We use sensitivities as the POD basis. We compare the output when the optimizer uses the reduced order model against results obtained with a full PDE based model. The solutions generated using the POD reduced model are comparable in residual norm to the solutions formed using only the full-scale model. The material parameters are similarly comparable. The time to solution when using the reduced model is reduced by at least an order of magnitude, as are the number of calls to the full model.
DA - 2011/12//
PY - 2011/12//
DO - 10.1016/j.advwatres.2011.09.007
VL - 34
IS - 12
SP - 1519-1526
SN - 1872-9657
KW - Proper Orthogonal Decomposition
KW - Optimization
KW - Parameter estimation
KW - Inverse problem
KW - Saturated groundwater flow
ER -
TY - JOUR
TI - Receding Horizon Control of HIV
AU - David, John
AU - Tran, Hien
AU - Banks, H. T.
T2 - OPTIMAL CONTROL APPLICATIONS & METHODS
AB - This paper describes a model of the immunologic response of the human immunodeficiency virus (HIV) in individuals. It then illustrates how a Receding Horizon Control (RHC) methodology can be used to drive the system to a stable equilibrium in which a strong immune response controls the viral load in the absence of drug treatment. We also illustrate how this feedback methodology can overcome unplanned treatment interruptions, inaccurate or incomplete data and imperfect model specification. We consider how ideas from stochastic estimation can be used in conjunction with RHC to create a robust treatment methodology. We then consider the performance of this methodology over random simulations of the previously considered clinical conditions. Copyright © 2010 John Wiley & Sons, Ltd.
DA - 2011///
PY - 2011///
DO - 10.1002/oca.969
VL - 32
IS - 6
SP - 681-699
SN - 1099-1514
KW - HIV model
KW - Receding Horizon Control
KW - extended Kalman filter
KW - state estimator
ER -
TY - JOUR
TI - Inverse data envelopment analysis model to preserve relative efficiency values: The case of variable returns to scale
AU - Lertworasirikul, Saowanee
AU - Charnsethikul, Peerayuth
AU - Fang, Shu-Cherng
T2 - Computers & Industrial Engineering
AB - This paper studies the inverse Data Envelopment Analysis (inverse DEA) for the case of variable returns to scale (inverse BCC). The developed inverse BCC model can preserve relative efficiency values of all decision making units (DMUs) in a new production possibility set composing of all current DMUs and a perturbed DMU with new input and output values. We consider the inverse BCC model for a resource allocation problem, where increases of some outputs and decreases of the other outputs of the considered DMU can be taken into account simultaneously. The inverse BCC problem is in the form of a multi-objective nonlinear programming model (MONLP), which is not easy to solve. We propose a linear programming model, which gives a Pareto-efficient solution to the inverse BCC problem. However, there exists at least an optimal solution to the proposed model if and only if the new output vector is in the set of current production possibility set. The proposed approach is illustrated via a case study of a motorcycle-part company.
DA - 2011/11//
PY - 2011/11//
DO - 10.1016/j.cie.2011.06.014
VL - 61
IS - 4
SP - 1017-1023
J2 - Computers & Industrial Engineering
LA - en
OP -
SN - 0360-8352
UR - http://dx.doi.org/10.1016/j.cie.2011.06.014
DB - Crossref
KW - Data envelopment analysis
KW - Inverse optimization
KW - Efficiency
KW - Performance analysis
KW - Resource allocation
ER -
TY - JOUR
TI - Generalized nonlinear H-infinity synthesis condition with its numerically efficient solution
AU - Zheng, Qian
AU - Wu, Fen
T2 - INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
AB - In this paper, we will first derive a general synthesis condition for the output-feedback ℋ︁∞ control of smooth nonlinear systems. Computationally efficient ℋ︁∞ control design procedure for a subclass of smooth nonlinear systems with polynomial vector field is then proposed by converting the resulting Hamilton-Jacobi-Isaacs inequalities from rational forms to their equivalent polynomial forms. Using quadratic Lyapunov functions, both the state-feedback and output-feedback problems will be reformulated as semi-definite optimization conditions and locally tractable solutions can be obtained through sum-of-squares (SOS) programming. The proposed nonlinear ℋ︁∞ design approach achieves significant relaxations on the plant structure compared with existing results in the literature. Moreover, the SOS-based solution algorithm provides an effective computational scheme to break the bottleneck in solving nonlinear ℋ︁∞ and optimal control problems. The proposed nonlinear ℋ︁∞ control approach has been applied to several examples to demonstrate its advantages over existing nonlinear control techniques and its usefulness to engineering problems. Copyright © 2010 John Wiley & Sons, Ltd.
DA - 2011/12//
PY - 2011/12//
DO - 10.1002/rnc.1682
VL - 21
IS - 18
SP - 2079-2100
SN - 1099-1239
KW - nonlinear H-infinity control
KW - output feedback
KW - polynomial nonlinear systems
KW - SOS programming
ER -
TY - JOUR
TI - Breakthrough Scanning, Supplier Knowledge Exchange, and New Product Development Performance
AU - Cousins, Paul D.
AU - Lawson, Benn
AU - Petersen, Kenneth J.
AU - Handfield, Robert B.
T2 - JOURNAL OF PRODUCT INNOVATION MANAGEMENT
AB - The ability of a firm to scan its environment for breakthrough innovations and develop new products is increasingly central to business success. However, many firms struggle to develop breakthrough innovations alone, and rely increasingly on their supply base to provide input in processing uncertain and ambiguous technological knowledge. This paper develops a theoretical framework, based in information processing theory, to investigate the effects of breakthrough search behaviors by the buyer firm on their technical proficiency, reliance on supplementary processing capacity with suppliers, and subsequent new product development and financial performance. Using data provided by 111 procurement executives from the United Kingdom, we find support for our hypotheses. Increased breakthrough scanning results in higher firm‐level technical proficiency, and also an increase in knowledge sharing with the firm's suppliers. A combination of a firm's technical capabilities and knowledge exchange with suppliers was found to result in improved new product development performance and financial performance. This study extends the supply relationship management and new product development literatures, and suggests implications for both research and practice.
DA - 2011/11//
PY - 2011/11//
DO - 10.1111/j.1540-5885.2011.00854.x
VL - 28
IS - 6
SP - 930-942
SN - 1540-5885
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80053978989&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Bandwidth allocation under end-to-end percentile delay bounds
AU - Anjum, Bushra
AU - Perros, Harry
AU - Mountrouidou, Xenia
AU - Kontovasilis, Kimon
T2 - INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT
AB - We describe an efficient and accurate approximation method for calculating the bandwidth that should be allocated on each link along the path of a point-to-point Multiprotocol Label Switching connection, so that the end-to-end delay D is less than or equal to a given value T with a probability γ, that is, P(D ≤ T) = γ. We model a connection by a tandem queuing network of infinite capacity queues. The arrival process of packets to the connection is assumed to be bursty and correlated and it is depicted by a two-stage Markov-Modulated Poisson Process. The service times are exponentially distributed. The proposed method uses only the first queue of the tandem queuing network to construct an upper and lower bound of the required bandwidth so that P(D ≤ T) = γ. Subsequently, we estimate the required bandwidth using a simple interpolation function between the two bounds. Extensive comparisons with simulation showed that the results obtained have an average relative error of 1.25%. Copyright © 2011 John Wiley & Sons, Ltd.
DA - 2011///
PY - 2011///
DO - 10.1002/nem.783
VL - 21
IS - 6
SP - 536-547
SN - 1099-1190
ER -
TY - JOUR
TI - THE REVIEWERS HATED IT! WHAT TO DO WHEN YOUR RESULTS DON'T ADD UP
AU - Handfield, Robert
T2 - JOURNAL OF SUPPLY CHAIN MANAGEMENT
AB - This essay explores the reasons why studies with non-significant results often do not get published, by looking back on a subset of submissions from the past 15 years. Suggestions are then provided to authors who face the dilemma of non-significance.
DA - 2011///
PY - 2011///
DO - 10.1111/j.1745-493x.2011.03243.x
VL - 47
IS - 4
SP - 11-16
SN - 1523-2409
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80054709343&partnerID=MN8TOARS
KW - research methods
KW - nonsignificant results
ER -
TY - JOUR
TI - Payment contracts in a preventive health care system: A perspective from Operations Management
AU - Yaesoubi, Reza
AU - Roberts, Stephen D.
T2 - JOURNAL OF HEALTH ECONOMICS
AB - We consider a health care system consisting of two noncooperative parties: a health purchaser (payer) and a health provider, where the interaction between the two parties is governed by a payment contract. We determine the contracts that coordinate the health purchaser-health provider relationship; i.e. the contracts that maximize the population's welfare while allowing each entity to optimize its own objective function. We show that under certain conditions (1) when the number of customers for a preventive medical intervention is verifiable, there exists a gate-keeping contract and a set of concave piecewise linear contracts that coordinate the system, and (2) when the number of customers is not verifiable, there exists a contract of bounded linear form and a set of incentive-feasible concave piecewise linear contracts that coordinate the system.
DA - 2011/12//
PY - 2011/12//
DO - 10.1016/j.jhealeco.2011.08.009
VL - 30
IS - 6
SP - 1188-1196
SN - 0167-6296
KW - Health care payment system
KW - Coordinating contracts
KW - Welfare
KW - Mechanism design
KW - Principal-agent model
KW - Preventive care
ER -
TY - JOUR
TI - MINIMAL EFFORT PROBLEMS AND THEIR TREATMENT BY SEMISMOOTH NEWTON METHODS
AU - Ito, Kazufumi
AU - Kunisch, Karl
T2 - SIAM JOURNAL ON CONTROL AND OPTIMIZATION
AB - The paper introduces minimum effort control problems. These provide an answer to the question of the smallest possible control bound which still allows us to drive the system to a target within a fixed time T. This is a counterpart to the time optimal control problem which minimizes the time required to drive the system to the target, given a control bound. The problem is formulated as an optimal control problem with pointwise constraint on the control. The necessary conditions of optimality are derived by Lagrange multiplier theory. The semismooth Newton method is applied to a properly regularized problem. Well-posedness and superlinear convergence of the semismooth Newton method are proved for linear control systems under a controllability condition. Numerical results are presented for demonstrating the applicability and feasibility of the proposed method.
DA - 2011///
PY - 2011///
DO - 10.1137/100784667
VL - 49
IS - 5
SP - 2083-2100
SN - 0363-0129
KW - minimum effort control
KW - Lagrange multiplier theory
KW - semismooth Newton method
ER -
TY - JOUR
TI - KARUSH-KUHN-TUCKER CONDITIONS FOR NONSMOOTH MATHEMATICAL PROGRAMMING PROBLEMS IN FUNCTION SPACES
AU - Ito, Kazufumi
AU - Kunisch, Karl
T2 - SIAM JOURNAL ON CONTROL AND OPTIMIZATION
AB - Lagrange multiplier rules for abstract optimization problems with mixed smooth and convex terms in the cost, with smooth equality constrained and convex inequality constraints, are presented. The typical case for the equality constraints that the theory is meant for is given by differential equations. Applications are given to $L^1$-minimum norm control problems, $L^\infty$-norm minimization, and a class of optimal control problems with distributed state constraints and nonsmooth cost.
DA - 2011///
PY - 2011///
DO - 10.1137/100817061
VL - 49
IS - 5
SP - 2133-2154
SN - 0363-0129
KW - KKT conditions
KW - nonsmooth optimization
KW - necessary optimality
ER -
TY - CONF
TI - Information delivery in large wireless networks with minimum energy expense
AU - Xu, Y.
AU - Wang, Wenye
AB - Energy efficient communication is a critical research problem in large-scale multihop wireless networks because of the limited energy supplies from batteries. We investigate in this paper the minimum energy required to fulfill various information delivery goals that correspond to the major communication paradigms in large wireless networks. We characterize the minimum energy requirement in two steps. We first derive the lower bounds on the energy consumption for all the possible solutions that deliver the information as required. We then design routing schemes that accomplish the information delivery tasks by using an amount of energy comparable to the lower bounds. Our work provides the fundamental understandings of energy needs and the efficient solutions for energy usages in major communication scenarios, which contribute to the rational dimensioning and wise utilization of the energy resources in large wireless networks.
C2 - 2011///
C3 - 2011 proceedings ieee infocom
DA - 2011///
DO - 10.1109/infcom.2011.5934950
SP - 1584–1592
ER -
TY - JOUR
TI - A new approach to nonlinear constrained Tikhonov regularization
AU - Ito, Kazufumi
AU - Jin, Bangti
T2 - INVERSE PROBLEMS
AB - We present a novel approach to nonlinear constrained Tikhonov regularization from the viewpoint of optimization theory. A second-order sufficient optimality condition is suggested as a nonlinearity condition to handle the nonlinearity of the forward operator. The approach is exploited to derive convergence rates results for a priori as well as a posteriori choice rules, e.g., discrepancy principle and balancing principle, for selecting the regularization parameter. The idea is further illustrated on a general class of parameter identification problems, for which (new) source and nonlinearity conditions are derived and the structural property of the nonlinearity term is revealed. A number of examples including identifying distributed parameters in elliptic differential equations are presented.
DA - 2011/10//
PY - 2011/10//
DO - 10.1088/0266-5611/27/10/105005
VL - 27
IS - 10
SP -
SN - 1361-6420
ER -
TY - JOUR
TI - A Stochastic Portfolio Optimization Model with Bounded Memory
AU - Chang, Mou-Hsiung
AU - Pang, Tao
AU - Yang, Yipeng
T2 - MATHEMATICS OF OPERATIONS RESEARCH
AB - This paper considers a portfolio management problem of Merton's type in which the risky asset return is related to the return history. The problem is modeled by a stochastic system with delay. The investor's goal is to choose the investment control as well as the consumption control to maximize his total expected, discounted utility. Under certain situations, we derive the explicit solutions in a finite dimensional space.
DA - 2011/11//
PY - 2011/11//
DO - 10.1287/moor.1110.0508
VL - 36
IS - 4
SP - 604-619
SN - 1526-5471
KW - stochastic delay equations
KW - optimal stochastic control
KW - Hamilton-Jacobi-Bellman equation
ER -
TY - JOUR
TI - Selecting and using views to compute aggregate queries
AU - Afrati, F.
AU - Chirkova, R.
T2 - Journal of Computer and System Sciences
AB - We consider a workload of aggregate queries and investigate the problem of selecting materialized views that (1) provide equivalent rewritings for all the queries, and (2) are optimal, in that the cost of evaluating the query workload is minimized. We consider conjunctive views and rewritings, with or without aggregation; in each rewriting, only one view contributes to computing the aggregated query output. We look at query rewriting using existing views and at view selection. In the query-rewriting problem, we give sufficient and necessary conditions for a rewriting to exist. For view selection, we prove complexity results. Finally, we give algorithms for obtaining rewritings and selecting views.
DA - 2011///
PY - 2011///
DO - 10.1016/j.jcss.2010.10.003
VL - 77
IS - 6
SP - 1079-1107
ER -
TY - JOUR
TI - Numerical Study of Surfactant-Laden Drop-Drop Interactions
AU - Xu, Jian-Jun
AU - Li, Zhilin
AU - Lowengrub, John
AU - Zhao, Hongkai
T2 - COMMUNICATIONS IN COMPUTATIONAL PHYSICS
AB - Abstract In this paper, we numerically investigate the effects of surfactant on drop-drop interactions in a 2D shear flow using a coupled level-set and immersed interface approach proposed in (Xu et al., J. Comput. Phys., 212 (2006), 590-616). We find that surfactant plays a critical and nontrivial role in drop-drop interactions. In particular, we find that the minimum distance between the drops is a non-monotone function of the surfactant coverage and Capillary number. This non-monotonic behavior, which does not occur for clean drops, is found to be due to the presence of Marangoni forces along the drop interfaces. This suggests that there are non-monotonic conditions for coalescence of surfactant-laden drops, as observed in recent experiments of Leal and co-workers. Although our study is two-dimensional, we believe that drop-drop interactions in three-dimensional flows should be qualitatively similar as the Maragoni forces in the near contact region in 3D should have a similar effect.
DA - 2011/8//
PY - 2011/8//
DO - 10.4208/cicp.090310.020610a
VL - 10
IS - 2
SP - 453-473
SN - 1991-7120
KW - Surfactants
KW - drops
KW - coalescence
KW - surface tension
KW - Marangoni effect
KW - level-set method
KW - immersed interface method
KW - Stokes flow
ER -
TY - JOUR
TI - Modelling and analysis of semiconductor manufacturing in a shrinking world: Challenges and successes
AU - Chien, C. F.
AU - Dauzere-Peres, S.
AU - Ehm, H.
AU - Fowler, J. W.
AU - Jiang, Z. B.
AU - Krishnaswamy, S.
AU - Lee, T. E.
AU - Monch, L.
AU - Uzsoy, R.
T2 - European Journal of Industrial Engineering
DA - 2011///
PY - 2011///
VL - 5
IS - 3
SP - 254-271
ER -
TY - JOUR
TI - KKT SOLUTION AND CONIC RELAXATION FOR SOLVING QUADRATICALLY CONSTRAINED QUADRATIC PROGRAMMING PROBLEMS
AU - Lu, Cheng
AU - Fang, Shu-Cherng
AU - Jin, Qingwei
AU - Wang, Zhenbo
AU - Xing, Wenxun
T2 - SIAM JOURNAL ON OPTIMIZATION
AB - To find a global optimal solution to the quadratically constrained quadratic programming problem, we explore the relationship between its Lagrangian multipliers and related linear conic programming problems. This study leads to a global optimality condition that is more general than the known positive semidefiniteness condition in the literature. Moreover, we propose a computational scheme that provides clues of designing effective algorithms for more solvable quadratically constrained quadratic programming problems.
DA - 2011///
PY - 2011///
DO - 10.1137/100793955
VL - 21
IS - 4
SP - 1475-1490
SN - 1095-7189
KW - quadratically constrained quadratic programming
KW - conic programming
KW - global optimality condition
KW - solvable condition
ER -
TY - JOUR
TI - Dynamic evasion-interrogation games with uncertainty in the context of electromagetics
AU - Banks, H. T.
AU - Hu, S. H.
AU - Ito, K.
AU - Muccio, S. G.
T2 - Numerical Mathematics: Theory, Methods and Applications
DA - 2011///
PY - 2011///
VL - 4
IS - 3
SP - 359-378
ER -
TY - JOUR
TI - Axle load distribution for mechanistic-empirical pavement design in North Carolina multidimensional clustering approach and decision tree development
AU - Sayyady, F.
AU - Stone, J. R.
AU - List, G. F.
AU - Jadoun, F. M.
AU - Kim, Y. R.
AU - Sajjadi, S.
T2 - Transportation Research Record
DA - 2011///
PY - 2011///
IS - 2256
SP - 159-168
ER -
TY - JOUR
TI - Predicting false discovery proportion under dependence
AU - Ghosal, S.
AU - Roy, A.
T2 - Journal of the American Statistical Association
DA - 2011///
PY - 2011///
VL - 106
IS - 495
SP - 1208-1218
ER -
TY - JOUR
TI - Auxiliary signal design for robust active fault detection of linear discrete-time systems
AU - Ashari, Alireza Esna
AU - Nikoukhah, Ramine
AU - Campbell, Stephen L.
T2 - AUTOMATICA
AB - In this paper, algorithms are proposed to design auxiliary signals for active fault detection based on a multi-model formulation of discrete-time systems. Two different scenarios are considered for this problem; the first one assumes there is no a priori information on initial conditions and no exogenous input signal, while the second allows for having a priori information and the possibility of having a known input in addition to the test signal. Approaches are proposed for solving these two types of problems which are capable of solving the problems efficiently. This is achieved by using a recursive approach based on the use of special Riccati equations. These algorithms can be used for systems of higher dimension and on longer time horizons than the existing methods.
DA - 2011/9//
PY - 2011/9//
DO - 10.1016/j.automatica.2011.06.009
VL - 47
IS - 9
SP - 1887-1895
SN - 1873-2836
KW - Fault detection
KW - Test signal reconstruction
KW - Model based fault detection
KW - Matrix Riccati equations
KW - Dynamic optimization
ER -
TY - JOUR
TI - Using time-varying tolls to optimize truck arrivals at ports
AU - Chen, Xiaoming
AU - Zhou, Xuesong
AU - List, George F.
T2 - TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANSPORTATION REVIEW
AB - An analytical point-wise stationary approximation model is proposed to analyze time-dependent truck queuing processes with stochastic service time distributions at gates and yards of a port terminal. A convex nonlinear programming model is developed which minimizes the total truck turn time and discomfort due to shifted arrival times. A two-phase optimization approach is used to first compute a system-optimal truck arrival pattern, and then find a desirable pattern of time-varying tolls that leads to the optimal arrival pattern. Numerical experiments are conducted to test the computational efficiency and accuracy of the proposed optimization models.
DA - 2011/11//
PY - 2011/11//
DO - 10.1016/j.tre.2011.04.001
VL - 47
IS - 6
SP - 965-982
SN - 1366-5545
KW - Port management
KW - First best toll pricing
KW - Time-dependent queuing model
KW - Stochastic service time distribution
ER -
TY - JOUR
TI - Studying Gene and Gene-Environment Effects of Uncommon and Common Variants on Continuous Traits: A Marker-Set Approach Using Gene-Trait Similarity Regression
AU - Tzeng, Jung-Ying
AU - Zhang, Daowen
AU - Pongpanich, Monnat
AU - Smith, Chris
AU - McCarthy, Mark I.
AU - Sale, Michele M.
AU - Worrall, Bradford B.
AU - Hsu, Fang-Chi
AU - Thomas, Duncan C.
AU - Sullivan, Patrick F.
T2 - AMERICAN JOURNAL OF HUMAN GENETICS
AB - Genomic association analyses of complex traits demand statistical tools that are capable of detecting small effects of common and rare variants and modeling complex interaction effects and yet are computationally feasible. In this work, we introduce a similarity-based regression method for assessing the main genetic and interaction effects of a group of markers on quantitative traits. The method uses genetic similarity to aggregate information from multiple polymorphic sites and integrates adaptive weights that depend on allele frequencies to accomodate common and uncommon variants. Collapsing information at the similarity level instead of the genotype level avoids canceling signals that have the opposite etiological effects and is applicable to any class of genetic variants without the need for dichotomizing the allele types. To assess gene-trait associations, we regress trait similarities for pairs of unrelated individuals on their genetic similarities and assess association by using a score test whose limiting distribution is derived in this work. The proposed regression framework allows for covariates, has the capacity to model both main and interaction effects, can be applied to a mixture of different polymorphism types, and is computationally efficient. These features make it an ideal tool for evaluating associations between phenotype and marker sets defined by linkage disequilibrium (LD) blocks, genes, or pathways in whole-genome analysis. Genomic association analyses of complex traits demand statistical tools that are capable of detecting small effects of common and rare variants and modeling complex interaction effects and yet are computationally feasible. In this work, we introduce a similarity-based regression method for assessing the main genetic and interaction effects of a group of markers on quantitative traits. The method uses genetic similarity to aggregate information from multiple polymorphic sites and integrates adaptive weights that depend on allele frequencies to accomodate common and uncommon variants. Collapsing information at the similarity level instead of the genotype level avoids canceling signals that have the opposite etiological effects and is applicable to any class of genetic variants without the need for dichotomizing the allele types. To assess gene-trait associations, we regress trait similarities for pairs of unrelated individuals on their genetic similarities and assess association by using a score test whose limiting distribution is derived in this work. The proposed regression framework allows for covariates, has the capacity to model both main and interaction effects, can be applied to a mixture of different polymorphism types, and is computationally efficient. These features make it an ideal tool for evaluating associations between phenotype and marker sets defined by linkage disequilibrium (LD) blocks, genes, or pathways in whole-genome analysis. Marker-set analysis refers to the joint evaluation of a group of markers for genetic association. These markers might be of various polymorphism types (e.g., a mixture of SNP, insertion-deletion variants [INDEL], block substitutions, copy-number variants, or inversion variants) but share certain common genomic features, such as participating in the same pathway, being in high linkage disequilibrium (LD), or being located within the same gene or conserved functional region. Marker-set analysis has drawn great attention in recent genome-wide and sequence-based association studies. It assesses the joint association of potentially correlated and interacting loci. It amplifies the detectability of the causal signals by aggregating small effects from multiple individual loci. Furthermore, because sequences and functions of genes are highly consistent across populations and species, a marker-set analysis increases the interpretability and replicability of the association findings. For whole-genome scans, it also offers a natural way of reducing the total number of tests and hence improves power by reducing the multiple-testing burden. For sequence-based studies, marker-set analysis accumulates information across multiple rare mutations and has a greatly enhanced power to detect rare variants that are hard for researchers to identify by traditional analysis methods. A variety of methods are available for detecting marker-set association, ranging from minimum p value or Fisher's combined methods1De la Cruz O. Wen X. Ke B. Song M. Nicolae D.L. Gene, region and pathway level analyses in whole-genome studies.Genet. Epidemiol. 2010; 34: 222-231PubMed Google Scholar, 2Fisher R.A. Statistical methods for research workers. Oliver and Boyd, London1932Google Scholar for single-marker tests to multimarker tests with a genotype- or haplotype-based scoring. Many recent methods fall in between the two extremes. These methods collapse information from all markers in the set and achieve a better balance between information and degrees of freedom. Depending on how the individual marker information is combined, we can roughly classify these approaches into four categories. Methods in the first category use the weighted sum of genotypes across markers, for example the LD-based weighting method,3Li M. Wang K. Grant S.F. Hakonarson H. Li C. ATOM: a powerful gene-based association test by combining optimally weighted markers.Bioinformatics. 2009; 25: 497-503Crossref PubMed Scopus (41) Google Scholar the weighted Fourier transform,4Wang T. Elston R.C. Improved power by use of a weighted score test for linkage disequilibrium mapping.Am. J. Hum. Genet. 2007; 80: 353-360Abstract Full Text Full Text PDF PubMed Scopus (94) Google Scholar and the PCA-based methods.5Gauderman W.J. Murcray C. Gilliland F. Conti D.V. Testing association between disease and multiple SNPs in a candidate gene.Genet. Epidemiol. 2007; 31: 383-395Crossref PubMed Scopus (168) Google Scholar, 6Wang K. Abbott D. A principal components regression approach to multilocus genetic association studies.Genet. Epidemiol. 2008; 32: 108-118Crossref PubMed Scopus (109) Google Scholar Recently, special versions of the weighted-sum methods based on allele frequencies were proposed to target rare variants.7Li B. Leal S.M. Methods for detecting associations with rare variants for common diseases: application to analysis of sequence data.Am. J. Hum. Genet. 2008; 83: 311-321Abstract Full Text Full Text PDF PubMed Scopus (1099) Google Scholar, 8Madsen B.E. Browning S.R. A groupwise association test for rare mutations using a weighted sum statistic.PLoS Genet. 2009; 5: e1000384Crossref PubMed Scopus (823) Google Scholar, 9Morgenthaler S. Thilly W.G. A strategy to discover genes that carry multi-allelic or mono-allelic risk for common diseases: a cohort allelic sums test (CAST).Mutat. Res. 2007; 615: 28-56Crossref PubMed Scopus (372) Google Scholar, 10Price A.L. Kryukov G.V. de Bakker P.I. Purcell S.M. Staples J. Wei L.J. Sunyaev S.R. Pooled association tests for rare variants in exon-resequencing studies.Am. J. Hum. Genet. 2010; 86: 832-838Abstract Full Text Full Text PDF PubMed Scopus (597) Google Scholar Methods of the second type model the genetic similarity of pairs of individuals and are also referred to as U-statistics approaches.11Tzeng J.Y. Byerley W. Devlin B. Roeder K. Wasserman L. Outlier detection and false discovery rates for whole-genome DNA matching.J. Am. Stat. Assoc. 2003; 98: 236-246Crossref Scopus (25) Google Scholar, 12Tzeng J.Y. Devlin B. Wasserman L. Roeder K. On the identification of disease mutations by the analysis of haplotype similarity and goodness of fit.Am. J. Hum. Genet. 2003; 72: 891-902Abstract Full Text Full Text PDF PubMed Scopus (112) Google Scholar, 13Schaid D.J. McDonnell S.K. Hebbring S.J. Cunningham J.M. Thibodeau S.N. Nonparametric tests of association of multiple genes with human disease.Am. J. Hum. Genet. 2005; 76: 780-793Abstract Full Text Full Text PDF PubMed Scopus (115) Google Scholar, 14Beckmann L. Thomas D.C. Fischer C. Chang-Claude J. Haplotype sharing analysis using mantel statistics.Hum. Hered. 2005; 59: 67-78Crossref PubMed Scopus (42) Google Scholar, 15Wessel J. Schork N.J. Generalized genomic distance-based regression methodology for multilocus association analysis.Am. J. Hum. Genet. 2006; 79: 792-806Abstract Full Text Full Text PDF PubMed Scopus (132) Google Scholar, 16Dempfle A. Hein R. Beckmann L. Scherag A. Nguyen T.T. Schäfer H. Chang-Claude J. Comparison of the power of haplotype-based versus single- and multilocus association methods for gene x environment (gene x sex) interactions and application to gene x smoking and gene x sex interactions in rheumatoid arthritis.BMC Proc. 2007; 1: S73Crossref PubMed Google Scholar, 17Tzeng J.Y. Zhang D. Chang S.M. Thomas D.C. Davidian M. Gene-trait similarity regression for multimarker-based association analysis.Biometrics. 2009; 65: 822-832Crossref PubMed Scopus (39) Google Scholar, 18Mukhopadhyay I. Feingold E. Weeks D.E. Thalamuthu A. Association tests using kernel-based measures of multi-locus genotype similarity between individuals.Genet. Epidemiol. 2010; 34: 213-221PubMed Google Scholar, 19Wei Z. Li M. Rebbeck T. Li H. U-statistics-based tests for multiple genes in genetic association studies.Ann. Hum. Genet. 2008; 72: 821-833Crossref PubMed Scopus (33) Google Scholar Methods of the third type are variance-component (VC) methods, which treat individual genetic effects as random effects and test for the corresponding VC to detect the global effect of a gene. Methods of this type include the SNP random-effects model,20Goeman J.J. van de Geer S.A. de Kort F. van Houwelingen H.C. A global test for groups of genes: testing association with a clinical outcome.Bioinformatics. 2004; 20: 93-99Crossref PubMed Scopus (793) Google Scholar, 21Goeman J.J. van de Geer S.A. van Houwelingen H.C. Testing against a high dimensional alternative.J. R. Stat. Soc. Series B Stat. Methodol. 2005; 68: 477-493Crossref Scopus (180) Google Scholar haplotype random-effects model,22Tzeng J.Y. Zhang D. Haplotype-based association analysis via variance-components score test.Am. J. Hum. Genet. 2007; 81: 927-938Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar and kernel-based methods.23Kwee L.C. Liu D. Lin X. Ghosh D. Epstein M.P. A powerful and flexible multilocus association test for quantitative traits.Am. J. Hum. Genet. 2008; 82: 386-397Abstract Full Text Full Text PDF PubMed Scopus (182) Google Scholar, 24Wu M.C. Kraft P. Epstein M.P. Taylor D.M. Chanock S.J. Hunter D.J. Lin X. Powerful SNP-set analysis for case-control genome-wide association studies.Am. J. Hum. Genet. 2010; 86: 929-942Abstract Full Text Full Text PDF PubMed Scopus (434) Google Scholar, 25Schaid D.J. Genomic similarity and kernel methods I: advancements by building on mathematical and statistical foundations.Hum. Hered. 2010; 70: 109-131Crossref PubMed Scopus (73) Google Scholar The fourth category includes other approaches that do not fit into the above categories, such as the c-alpha test,26Neale B.M. Rivas M.A. Voight B.F. Altshuler D. Devlin B. Orho-Melander M. Kathiresan S. Purcell S.M. Roeder K. Daly M.J. Testing for an unusual distribution of rare variants.PLoS Genet. 2011; 7: e1001322Crossref PubMed Scopus (462) Google Scholar the group additive regression model,27Luan Y. Li H. Group additive regression models for genomic data analysis.Biostatistics. 2008; 9: 100-113Crossref PubMed Scopus (38) Google Scholar Tukey's model,28Chatterjee N. Kalaylioglu Z. Moslehi R. Peters U. Wacholder S. Powerful multilocus tests of genetic association in the presence of gene-gene and gene-environment interactions.Am. J. Hum. Genet. 2006; 79: 1002-1016Abstract Full Text Full Text PDF PubMed Scopus (130) Google Scholar and entropy-based methods.29Zhao J. Boerwinkle E. Xiong M. An entropy-based statistic for genomewide association studies.Am. J. Hum. Genet. 2005; 77: 27-40Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar Although most marker-set methods have concentrated on detecting genetic main effects, here we focus on methods for studying gene-environment (G × E) interactions. Identifying genetic variants with heterogeneous effects under different environmental exposures is crucial for understanding individualized medicine, studying pharmacogenetics, characterizing underlying biological mechanisms, and uncovering unexplained heritability.30Dempfle A. Scherag A. Hein R. Beckmann L. Chang-Claude J. Schäfer H. Gene-environment interactions for complex traits: definitions, methodological requirements and challenges.Eur. J. Hum. Genet. 2008; 16: 1164-1172Crossref PubMed Scopus (131) Google Scholar, 31Thomas D. Gene—environment-wide association studies: emerging approaches.Nat. Rev. Genet. 2010; 11: 259-272Crossref PubMed Scopus (506) Google Scholar Marker-set analysis provides an ideal framework for the study of G × E interactions. The marker set, either defined by genes, pathways, or functions, provides a biologically sensible unit for the G component, and the loci in a set can be assessed jointly for whether their effects are modified under different environmental exposures. In addition, the potential power gain brought by the marker-set analysis—either through aggregating genetic signals or by reducing multiple-testing penalty—can alleviate the data-hungry nature of detecting G × E interactions. Typically, a G × E test would require sample sizes at least four times larger than a main effect test for detecting an effect of comparable magnitude.30Dempfle A. Scherag A. Hein R. Beckmann L. Chang-Claude J. Schäfer H. Gene-environment interactions for complex traits: definitions, methodological requirements and challenges.Eur. J. Hum. Genet. 2008; 16: 1164-1172Crossref PubMed Scopus (131) Google Scholar, 31Thomas D. Gene—environment-wide association studies: emerging approaches.Nat. Rev. Genet. 2010; 11: 259-272Crossref PubMed Scopus (506) Google Scholar, 32Lindström S. Yen Y.C. Spiegelman D. Kraft P. The impact of gene-environment dependence and misclassification in genetic association studies incorporating gene-environment interactions.Hum. Hered. 2009; 68: 171-181Crossref PubMed Scopus (34) Google Scholar, 33Smith P.G. Day N.E. The design of case-control studies: the influence of confounding and interaction effects.Int. J. Epidemiol. 1984; 13: 356-365Crossref PubMed Scopus (233) Google Scholar Furthermore, many G × E studies are based on conceptual models for candidate pathways, in which a set of genes are selected and studied together.31Thomas D. Gene—environment-wide association studies: emerging approaches.Nat. Rev. Genet. 2010; 11: 259-272Crossref PubMed Scopus (506) Google Scholar, 34Thomas D. Methods for investigating gene-environment interactions in candidate pathway and genome-wide association studies.Annu. Rev. Public Health. 2010; 31: 21-36Crossref PubMed Scopus (119) Google Scholar Marker-set analysis offers a suitable tool for the evaluation of the overall effect of the postulated pathways when assessing G × E interactions. The marker-set G × E method we present focuses on quantitative traits and uses pairwise genetic similarity as a tool to aggregate marker information (i.e., the second category in the above method categorization). Our approach differs from those in the literature on gene/pathway level analysis in the following aspects. First, we introduce a framework for incorporating interaction effects in similarity-based methods. To be useful for G × E studies with either confirmatory or exploratory aims, we develop a series of tests to suit different purposes, including a test for detecting G × E interactions, a test for detecting marginal main effects, and a joint test for detecting the overall association induced either by genetic main effects or by G × E interactions. The joint test serves as a good tool when little is known a priori about the genetic heterogeneity across exposure strata and provides power across a wide range of the unknown underlying true structures. Second, the proposed method can collapse information from a mixture of different types of variants and is designed to detect common and uncommon variants. Both are desirable features when more classes of DNA variants are available. Finally, we illustrate how similarity-based collapsing methods can be equivalent to VC methods (i.e., category 3 in the method categorization), which are found to have better main-effect performance than several other marker-set approaches.24Wu M.C. Kraft P. Epstein M.P. Taylor D.M. Chanock S.J. Hunter D.J. Lin X. Powerful SNP-set analysis for case-control genome-wide association studies.Am. J. Hum. Genet. 2010; 86: 929-942Abstract Full Text Full Text PDF PubMed Scopus (434) Google Scholar, 35Ballard D.H. Cho J. Zhao H. Comparisons of multi-marker association methods to detect association between a candidate region and disease.Genet. Epidemiol. 2010; 34: 201-212Crossref PubMed Scopus (62) Google Scholar, 36Chapman J. Whittaker J. Analysis of multiple SNPs in a candidate gene or region.Genet. Epidemiol. 2008; 32: 560-566Crossref PubMed Scopus (82) Google Scholar, 37Fridley B.L. Jenkins G.D. Biernacka J.M. Self-contained gene-set analysis of expression data: an evaluation of existing and novel methods.PLoS ONE. 2010; 5: e12693Crossref PubMed Scopus (49) Google Scholar Through simulation, we show the validity of the test and investigate the power of the proposed approach under a wide range of scenarios. We illustrate the utility of the proposed method by using the samples from the Vitamin Intervention for Stroke Prevention (VISP) trial. In this study, candidate genes across the genome were selected for the evaluation of the gene and gene-age interaction effects on the change in fasting homocysteine (Hcy) level following a 2 hr methionine load test. We use the following notations. For individual i (i=1,2,…,n), let Yi be the continuous trait, Xi be the K×1 covariate vector excluding the intercept term and standardized to mean = 0 and variance = 1, and Gm,i be the allele-count vector of marker m for person i, with the length equal to the number of distinct alleles at marker m (denoted by ℓm), m=1,2,⋯,M. For example, Gm,i=[2,0] if person i has genotype 11 at SNP m and = [1,1] if person i has genotype 10. To fix the idea, we consider K=1, but the method described here also applies to K>1. For each pair of individuals i and j, we measure the trait similarity Zij and genetic similarity Sij of the targeted marker set. We then regress the trait similarity on the genetic similarity and detect gene-trait association by testing for the significance of relevant regression coefficients. The trait similarity Zij is quantified through trait covariance by taking the product of the trait residuals of subjects i and j. Let μi be the subject-specific mean of trait value adjusted for the covariate information; then we set Zij=(Yi−μi)(Yj−μj), where μi=γ0+Xiγ and (γ0,γ) is the covariate effects including the intercept. The genetic similarity Sij is measured by the average of the weighted allele matching score (weighted matching score for short) between subjects i and j across the M markers. It takes the form of Sij=1/M×∑m=1MGm,iTWmGm,j, in which Wm is an ℓm×ℓm matrix that specifies the weighting scheme. As an illustration, consider a SNP and the weight Wm=I2×2. Then SAA,AA=4, SAA,Aa=2, and SAA,aa=0. When quantifying genetic similarity, one can use weights based on allele frequencies, the degree of evolutionary conservation, or the functionality of the variations to better target genetic variants of certain features (e.g., rare, functional).15Wessel J. Schork N.J. Generalized genomic distance-based regression methodology for multilocus association analysis.Am. J. Hum. Genet. 2006; 79: 792-806Abstract Full Text Full Text PDF PubMed Scopus (132) Google Scholar, 25Schaid D.J. Genomic similarity and kernel methods I: advancements by building on mathematical and statistical foundations.Hum. Hered. 2010; 70: 109-131Crossref PubMed Scopus (73) Google Scholar, 38Schaid D.J. Genomic similarity and kernel methods II: methods for genomic information.Hum. Hered. 2010; 70: 132-140Crossref PubMed Scopus (60) Google Scholar For example, to upweight similarities contributed by rare variants, we define the frequency of allele a at marker m as qa,m and set Wm=diag{1/qa,m} or diag{1/qa,m} to upweight the similarity in rare alleles.23Kwee L.C. Liu D. Lin X. Ghosh D. Epstein M.P. A powerful and flexible multilocus association test for quantitative traits.Am. J. Hum. Genet. 2008; 82: 386-397Abstract Full Text Full Text PDF PubMed Scopus (182) Google Scholar, 24Wu M.C. Kraft P. Epstein M.P. Taylor D.M. Chanock S.J. Hunter D.J. Lin X. Powerful SNP-set analysis for case-control genome-wide association studies.Am. J. Hum. Genet. 2010; 86: 929-942Abstract Full Text Full Text PDF PubMed Scopus (434) Google Scholar The proposed gene-trait similarity regression model has the following form:E(Zij|X,H)=b×Sij+d×Sij×XiXj,i≠j.(Equation 1) Because baseline and covariate effects have been adjusted for Zij, the regression has a zero intercept and does not have the covariate term XiXj. This contention will become more obvious from the viewpoint of variance components in the following paragraph. Equation 1 incorporates information about genetic main effects and gene-environment interactions and hence allows the possibility of a genetic effect to be modified by an environmental exposure. Under Equation 1, one can evaluate the overall genetic association by performing a joint test of genetic main effects and gene-environment interactions for H0:b=d=0. To assess gene-environment interactions only, one can perform a G × E test by examining H0:d=0. Finally, one can evaluate the marginal main effects by examining the main effect term and testing for H0:b=0 under the constraint of d=0. We refer to this test as the G test. The G test can be used as a subsequent test when a G × E test fails to reject H0, or it can be used as an alternative way to detect the overall genetic association. Because interactive factors can often exhibit a marginal effect even when the interaction terms are not modeled,39Cordell H.J. Epistasis: what it means, what it doesn't mean, and statistical methods to detect it in humans.Hum. Mol. Genet. 2002; 11: 2463-2468Crossref PubMed Scopus (797) Google Scholar, 40Hirschhorn J.N. Daly M.J. Genome-wide association studies for common diseases and complex traits.Nat. Rev. Genet. 2005; 6: 95-108Crossref PubMed Scopus (2150) Google Scholar the G test is often used to perform genome screening in common practice. Compared to the joint test, the G test uses fewer degrees of freedom and hence is more powerful when there are no gene-environment interactions or when the interaction effects are big, but it might be less powerful when the genetic effect is restricted to the exposure group.41Kraft P. Yen Y.C. Stram D.O. Morrison J. Gauderman W.J. Exploiting gene-environment interaction to detect genetic associations.Hum. Hered. 2007; 63: 111-119Crossref PubMed Scopus (329) Google Scholar The test statistics for G × E, G, and joint tests can be derived through the equivalence between the similarity regression models and the haplotype random-effects model.17Tzeng J.Y. Zhang D. Chang S.M. Thomas D.C. Davidian M. Gene-trait similarity regression for multimarker-based association analysis.Biometrics. 2009; 65: 822-832Crossref PubMed Scopus (39) Google Scholar Consider a working haplotype random-effects model:Yi=γ0+Xiγ+HiTβ+XiHiTλ+ei,(Equation 2) where ei∼N(0,σ), Hi is the L×1 haplotype vector, L is the number of distinct haplotypes observed in the population, βL×1∼ N (0,τR),λL×1∼N(0,ϕR), and R is an L×L matrix in which the (h,k) th entry is equal to the similarity between haplotypes h and k, quantified by the weighted matching score. Under the working mixed model (Equation 2), the trait covariance between individuals i and j (i≠j) iscov(Yi,Yj|X,H)=HiTcov(β)Hj+XiHiTcov(λ)HjXj=τ×HiTRHj+ϕ×XiXj×HiTRHj=τ×Sij+ϕ×XiXj×Sij(Equation 3) The last line follows from the fact that HiTRHj=1/M×∑m=1MGm,iTWmGm,j17. Comparing (Equation 1), (Equation 3), we have b=τ and d=ϕ. That is, the regression coefficients in the similarity regression are the variance components in the mixed model (Equation 2). Therefore, following similar derivations in Tzeng and Zhang22Tzeng J.Y. Zhang D. Haplotype-based association analysis via variance-components score test.Am. J. Hum. Genet. 2007; 81: 927-938Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar and Zhang and Lin,42Zhang D. Lin X. Hypothesis testing in semiparametric additive mixed models.Biostatistics. 2003; 4: 57-74Crossref PubMed Scopus (97) Google Scholar we obtain the score test statistics for G × E test, G test, and the joint test as follows:TG×E=YTP1DSDP1Y|ϕ=0,τ=τˆ,σ=σˆ,TG=YTP0SP0Y|ϕ=0,τ=0,σ=σ˜,andTjoint=YTP0(S+DSD)P0Y|ϕ=0,τ=0,σ=σ˜. In the above equations, Yn×1T=(Y1,⋯,Yn), Dn×n=diag{Xi}, and S={Sij} where Sij=HiTRHj; matrix Pt=Vt−1−Vt−1X(XTVt−1X)−1XTVt−1,t=0,1, where V0=σI,V1=τS+σI. The quantities (τˆ,σˆ) are the REML estimates for (τ,σ) obtained under H0:ϕ=0, and σ˜ is the REML estimate for σ under H0:ϕ=τ=0. These estimates are given in Appendix A. As shown in Appendix B, these test statistics follow a weighted χ2 distribution, and the p values can be calculated with the three-moment approximation.43Pearson E.S. Note on an approximation to the distribution of non-central χ2.Biometrika. 1959; 46: 364Crossref Google Scholar, 44Imhof J.P. Computing the Distribution of Quadratic Forms in Normal Variables.Biometrika. 1961; 48: 419-426Crossref Google Scholar There are a few remarks regarding the similarity-based marker-set methods. The similarity regression aggregates marker information through a sum of genotype similarity across markers instead of a sum of genotypes. Compared to genotype sums, aggregating information through similarity can prevent signals of opposite directions from being canceled. In addition, because Gm,i takes integer or dosage counts and can be of any length, this approach can work with typed and imputed genotype calls and is applicable to a mixture of different types of variants without having to dichotomize the variants. We performed simulations based on HapMap 3 data to assess the performance of the proposed tests. We obtained a haplotype population consisting of 234 phased haplotypes from chromosome 21 of the CEU (Utah residents with ancestry from northern and western Europe) samples in HapMap 3. To obtain a variety of risk allele frequencies and LD patterns of a marker set, we defined a marker set as a 10 SNP region, and used a nonoverlapping sliding window on chromosome 21 to obtain 1734 regions. Given a marker-set region, we generated haplotypes for 500 individuals by randomly sampling 500 pairs of haplotypes with replacement from the 234 haplotypes under a Hardy-Weinberg equilibrium assumption. Because the rarest allele frequency we can obtain is 1/234≈0.004, we used a relatively small sample size (n = 500) to assure genetic heterogeneity attributable to rare mutations. Given a 10 SNP region, the 5th and the 10th SNPs were set to be the risk loci, and their genotypes for individual i are denoted by G1i and G2i∈{0,1,2}, respectively. We generated Xi∼N(0,1). Then on the basis of the genetic and covariate information of individual i, the trait value Yi was sampled from a normal distribution with mean = γ0+γ1Xi+γG1G1i+γG2G2i+γGE1XiG1i+γGE2XiG2i and variance = v2, where γ0 and γ1 were set to be 1, and v2 was determined so that the heritability was around 0.1 to 0.2. For type I error rate analysis, we set (γG1,γG2,γGE1,γGE2)=(0,0,0,0) for all three tests and also (0.2,0.2,0,0) for G× E test. For power analysis, we set (γG1,γG2,γGE1,γGE2)=(0.25,0.25,0.3,0.3). These values were chosen so that the power of the joint tests is not too close to 1, whereas the power of G×E and G tests is not too close to the nominal level of 0.0005. Each region was analyzed with the proposed similarity regression with three weighting schemes considered in the literature:23Kwee L.C. Liu D. Lin X. Ghosh D. Epstein M.P. A powerful and flexible multilocus association test for quantitative traits.Am. J. Hum. Genet. 2008; 82: 386-397Abstract Full Text Full Text PDF PubMed Scopus (182) Google Scholar, 24Wu M.C. Kraft P. Epstein M.P. Taylor D.M. Chanock S.J. Hunter D.J. Lin X. Powerful SNP-set analysis for case-control genome-wide association studies.Am. J. Hum. Genet. 2010; 86: 929-942Abstract Full Text Full Text PDF PubMed Scopus (434) Google Scholar (1)Wm=diag{1/qm}(referred to as SIM1), (2) Wm=diag{1/qm}(referred to as SIM2), and (3) Wm=diag{1}(referred to as SIM0). The results were compared to two benchmark methods, the single-SNP minimum-p-value method (referred to as SNP) and the multi-SNP haplotype-based method (referred to as HAP). In all analyses, the two risk loci were excluded, and the phase information was removed. For the minimum p value method, we used the minimum of the p values from the G × E, G and joint tests for the eight SNPs, and the significance threshold was determined with the multiple-testing correction method of Moskvina and Schmidt.45Moskvina V. Schmidt K.M. On multiple-testing correction in genome-wide association studies.Genet. Epidemiol. 2008; 32: 567-573Crossref PubMed Scopus (183) Google Scholar This method estimates the effective number of independent tests for correlated SNPs at a given overall type I error rate and calculates the significance level for the individual tests accordingly. For the haplotype-based analysis, we used the widely used R package haplo.stats to carry out standard haplotype regression analysis. Specifically, we used haplo.glm46Lake S.L. Lyon H. Tantisira K. Silverman E.K. Weiss S.T. Laird N.M. Schaid D.J. Estimation and tests of haplotype-environment interaction when linkage phase is ambig
DA - 2011/8/12/
PY - 2011/8/12/
DO - 10.1016/j.ajhg.2011.07.007
VL - 89
IS - 2
SP - 277-288
SN - 1537-6605
ER -
TY - JOUR
TI - Statistical Parameter Estimation for Macro Fiber Composite Actuators using the Homogenized Energy Model
AU - Hu, Zhengzheng
AU - Smith, Ralph C.
AU - Stuebner, Michael
AU - Hays, Michael
AU - Oates, William S.
T2 - BEHAVIOR AND MECHANICS OF MULTIFUNCTIONAL MATERIALS AND COMPOSITES 2011
AB - Macro Fiber Composites (MFC) are planar actuators comprised of PZT fibers embedded in an epoxy matrix that
is sandwiched between electrodes. Due to their construction, they exhibit significant durability and flexibility in
addition to being lightweight and providing broadband inputs. They are presently being considered for a range
of applications including positioning and control of membrane mirrors and configurable aerospace structures.
However, they also exhibit hysteresis and constitutive nonlinearities that must be incorporated in models to
achieve the full potential of the devices. In this paper, we discuss the development of a model that quantifies the
hysteresis and constitutive nonlinearities in a manner that promotes subsequent control design. The constitutive
model is constructed using the homogenized energy framework for ferroelectric hysteresis and used to develop
resulting system models. The performance of the models is validated with experimental data.
DA - 2011///
PY - 2011///
DO - 10.1117/12.884622
VL - 7978
SP -
SN - 0277-786X
KW - Nonlinear piezoelectric model
KW - macro fiber composite
ER -
TY - JOUR
TI - Predicting County-Level Southern Pine Beetle Outbreaks From Neighborhood Patterns
AU - Duehl, Adrian
AU - Bishir, John
AU - Hain, Fred P.
T2 - ENVIRONMENTAL ENTOMOLOGY
AB - The southern pine beetle (Dendroctonus frontalis Zimmermann, Coleoptera: Curculionidae) is the most destructive insect in southern forests. States have kept county-level records on the locations of beetle outbreaks for the past 50 yr. This study determined how accurately patterns of county-level infestations in preceding years could predict infestation occurrence in the current year and if there were emergent patterns that correlated strongly with beetle outbreaks. A variety of methods were tested as infestation predictors, including quantification of either the exact locations of infested grid cells during one or two preceding years, or the neighborhood infestation intensity (number of infested cells in a neighborhood) in these years. The methods had similar predictive abilities, but the simpler methods performed somewhat better than the more complex ones. The factors most correlated with infestations in future years were infestation in the current year and the number of surrounding counties that were infested. Infestation history helped to predict the probability of future infestations in a region, but county-level patterns alone left much of the year-to-year variability unexplained.
DA - 2011/4//
PY - 2011/4//
DO - 10.1603/en08275
VL - 40
IS - 2
SP - 273-280
SN - 0046-225X
KW - southern pine beetle
KW - cellular automata
KW - county pattern
KW - forest damage
ER -
TY - JOUR
TI - IMPORTANCE SAMPLING FOR A MONTE CARLO MATRIX MULTIPLICATION ALGORITHM, WITH APPLICATION TO INFORMATION RETRIEVAL
AU - Eriksson-Bique, Sylvester
AU - Solbrig, Mary
AU - Stefanelli, Michael
AU - Warkentin, Sarah
AU - Abbey, Ralph
AU - Ipsen, Ilse C. F.
T2 - SIAM JOURNAL ON SCIENTIFIC COMPUTING
AB - We perform importance sampling for a randomized matrix multiplication algorithm by Drineas, Kannan, and Mahoney and derive probabilities that minimize the expected value (with regard to the distributions of the matrix elements) of the variance. We compare these optimized probabilities with uniform probabilities and derive conditions under which the actual variance of the optimized probabilities is lower. Numerical experiments with query matching in information retrieval applications illustrate that the optimized probabilities produce more accurate matchings than the uniform probabilities and that they can also be computed efficiently.
DA - 2011///
PY - 2011///
DO - 10.1137/10080659x
VL - 33
IS - 4
SP - 1689-1706
SN - 1095-7197
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80052734652&partnerID=MN8TOARS
KW - randomized algorithm
KW - expected value
KW - variance
KW - term-by-document matrix
KW - query matching
ER -
TY - JOUR
TI - Forces, trends, and decisions in pharmaceutical supply chain management
AU - Rossetti, C.L.
AU - Handfield, Robert
AU - Dooley, K.J.
T2 - International Journal of Physical Distribution and Logistics Management
AB - Purpose The purpose of this paper is to identify and examine the major forces that are changing the way biopharmaceutical medications are purchased, distributed, and sold throughout the supply chain. This will become important as healthcare reform moves forward, and logistics will be transformed in this industry. Design/methodology/approach Multiple interviews with key informants at each level of the value chain were combined with manifest text analysis from practitioner articles to derive key insights into the primary change drivers influencing the future of the biopharmaceutical supply chain. Findings The research discovered radical shifts in the structure of the biopharmaceutical supply chain. Future research into biopharmaceutical supply chain practices will need to explore three primary issues: How will supply chain member compensation influence the power of parties within the network? How will the role of supply chain intermediaries change the landscape of medication delivery to the end customer? What impact will the role of regulatory constraints on product pedigree and proliferation have on this network? The relationship between these forces is mediated by operations strategy concerning inventory policy, supply chain visibility, and desired service levels. Research limitations/implications The research was based on multiple interviews with a convenience sample, as well as text analysis from practitioner articles. These findings are an initial step to guide future more in‐depth research for this dynamic and contextually rich supply chain environment that impacts consumers in every country in the world. Originality/value The paper adds insights into the pharmaceutical supply chain, examining this from multiple perspectives.
DA - 2011///
PY - 2011///
DO - 10.1108/09600031111147835
VL - 41
IS - 6
SP - 601-622
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79960293063&partnerID=MN8TOARS
KW - Biopharmaceutical
KW - Supply chain
KW - Intermediaries
KW - Supply chain regulation
KW - Distribution strategy
KW - Supply chain management
ER -
TY - JOUR
TI - Fast Exact ILP Decompositions for Ring RWA
AU - Yetginer, Emre
AU - Liu, Zeyu
AU - Rouskas, George N.
T2 - JOURNAL OF OPTICAL COMMUNICATIONS AND NETWORKING
AB - Wavelength division multiplexing rings are now capable of supporting more than 100 wavelengths over a single fiber. Conventional link and path formulations for the routing and wavelength assignment problem are inefficient due to the inherent symmetry in wavelength assignment and the fact that the problem size increases fast with the number of wavelengths. Although a formulation based on maximal independent sets (MIS) does not have these drawbacks, it suffers from exponential growth in the number of variables with increasing network size. We develop a new ILP (integer linear program) formulation based on the key idea of partitioning the path set and representing the MIS in the original network using the independent sets calculated in each of these partitions. This exact decomposition trades off the number of variables with the number of constraints and, as a result, achieves a much better scalability in terms of network dimension. Numerical results on ring networks of various sizes demonstrate that this new ILP decomposition achieves a decrease of several orders of magnitude in running time compared to existing formulations. Our main contribution is a novel and extremely fast technique for obtaining, in a few seconds using commodity CPUs, optimal solutions to instances of maximum size SONET rings with any number of wavelengths; such instances cannot be tackled with classical formulations without vast investments in computational resources and time.
DA - 2011/7//
PY - 2011/7//
DO - 10.1364/jocn.3.000577
VL - 3
IS - 7
SP - 577-586
SN - 1943-0639
KW - Integer linear programming (ILP)
KW - Ring networks
KW - Routing and wavelength assignment (RWA)
ER -
TY - JOUR
TI - Adaptive Control Design for Hysteretic Smart Systems
AU - McMahan, Jerry A.
AU - Smith, Ralph C.
T2 - BEHAVIOR AND MECHANICS OF MULTIFUNCTIONAL MATERIALS AND COMPOSITES 2011
AB - Ferroelectric and ferromagnetic actuators are being considered for a range of industrial, aerospace, aeronautic and biomedical applications due to their unique transduction capabilities. However, they also exhibit hysteretic and nonlinear behavior that must be accommodated in models and control designs. If uncompensated, these effects can yield reduced system performance and, in the worst case, can produce unpredictable behavior of the control system. In this paper, we address the development of adaptive control designs for hysteretic systems. We review an MRAC-like adaptive control algorithm used to track a reference trajectory while computing online estimates for certain model parameters. This method is incorporated in a composite control algorithm to improve the tracking capabilities of the system. Issues arising in the implementation of these algorithms are addressed, and a numerical example is presented, comparing the results of each method.
DA - 2011///
PY - 2011///
DO - 10.1117/12.884621
VL - 7978
SP -
SN - 1996-756X
KW - smart systems
KW - hysteresis
KW - adaptive control
KW - composite control
ER -
TY - JOUR
TI - Performance of Skart: A Skewness- and Autoregression-Adjusted Batch Means Procedure for Simulation Analysis
AU - Tafazzoli, Ali
AU - Wilson, James R.
AU - Lada, Emily K.
AU - Steiger, Natalie M.
T2 - INFORMS JOURNAL ON COMPUTING
AB - An analysis is given for an extensive experimental performance evaluation of Skart, an automated sequential batch means procedure for constructing an asymptotically valid confidence interval (CI) on the steady-state mean of a simulation output process. Skart is designed to deliver a CI satisfying user-specified requirements on absolute or relative precision as well as coverage probability. Skart exploits separate adjustments to the half-length of the classical batch means CI so as to account for the effects on the distribution of the underlying Student's t-statistic that arise from skewness (nonnormality) and autocorrelation of the batch means. Skart also delivers a point estimator for the steady-state mean that is approximately free of initialization bias. In an experimental performance evaluation involving a wide range of test processes, Skart compared favorably with other steady-state simulation analysis methods—namely, its predecessors ASAP3, WASSP, and SBatch, as well as ABATCH, LBATCH, the Heidelberger–Welch procedure, and the Law–Carson procedure. Specifically, Skart exhibited competitive sampling efficiency and closer conformance to the given CI coverage probabilities than the other procedures, especially in the most difficult test processes.
DA - 2011///
PY - 2011///
DO - 10.1287/ijoc.1100.0401
VL - 23
IS - 2
SP - 297-314
SN - 1526-5528
KW - simulation
KW - statistical analysis
KW - steady-state analysis
KW - method of batch means
KW - Cornish-Fisher expansion
KW - autoregressive representation
ER -
TY - JOUR
TI - Nonholonomic Hamilton-Jacobi theory via Chaplygin Hamiltonization
AU - Ohsawa, Tomoki
AU - Fernandez, Oscar E.
AU - Bloch, Anthony M.
AU - Zenkov, Dmitry V.
T2 - JOURNAL OF GEOMETRY AND PHYSICS
AB - We develop Hamilton-Jacobi theory for Chaplygin systems, a certain class of nonholonomic mechanical systems with symmetries, using a technique called Hamiltonization, which transforms nonholonomic systems into Hamiltonian systems. We give a geometric account of the Hamiltonization, identify necessary and sufficient conditions for Hamiltonization, and apply the conventional Hamilton-Jacobi theory to the Hamiltonized systems. We show, under a certain sufficient condition for Hamiltonization, that the solutions to the Hamilton-Jacobi equation associated with the Hamiltonized system also solve the nonholonomic Hamilton-Jacobi equation associated with the original Chaplygin system. The results are illustrated through several examples.
DA - 2011/8//
PY - 2011/8//
DO - 10.1016/j.geomphys.2011.02.015
VL - 61
IS - 8
SP - 1263-1291
SN - 1879-1662
KW - Nonholonomic mechanics
KW - Hamilton-Jacobi theory
KW - Reduction
KW - Hamiltonization
ER -
TY - JOUR
TI - Intertemporal Discount Factors as a Measure of Trustworthiness in Electronic Commerce
AU - Hazard, Christopher J.
AU - Singh, Munindar P.
T2 - IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING
AB - In multiagent interactions, such as e-commerce and file sharing, being able to accurately assess the trustworthiness of others is important for agents to protect themselves from losing utility. Focusing on rational agents in e-commerce, we prove that an agent's discount factor (time preference of utility) is a direct measure of the agent's trustworthiness for a set of reasonably general assumptions and definitions. We propose a general list of desiderata for trust systems and discuss how discount factors as trustworthiness meet these desiderata. We discuss how discount factors are a robust measure when entering commitments that exhibit moral hazards. Using an online market as a motivating example, we derive some analytical methods both for measuring discount factors and for aggregating the measurements.
DA - 2011/5//
PY - 2011/5//
DO - 10.1109/tkde.2010.141
VL - 23
IS - 5
SP - 699-712
SN - 1558-2191
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79953171081&partnerID=MN8TOARS
KW - Trust
KW - reputation
KW - intertemporal discounting
ER -
TY - JOUR
TI - Bayesian smoothing of photon-limited images with applications in astronomy
AU - White, J. T.
AU - Ghosal, S.
T2 - Journal of the Royal Statistical Society. Series B, Statistical Methodology
DA - 2011///
PY - 2011///
VL - 73
SP - 579-599
ER -
TY - JOUR
TI - Adding Percentiles of Erlangian Distributions
AU - Anjum, Bushra
AU - Perros, Harry
T2 - IEEE COMMUNICATIONS LETTERS
AB - In networking, enterprise computing and many other areas the issue of adding percentiles of a performance metric, such as the response time, arises regularly. Percentiles cannot be added using the arithmetic sum, and surprisingly there are no known formulae that permit us to do so correctly. In this paper, we obtain an exact analytical expression for adding percentiles of random variables which can be represented by a series of generalized exponential stages (e.g., Erlang, hypoexponential and two-stage Coxian). We demonstrate the applicability of our results by an example in which we use our expressions in the Dijkstra's algorithm to calculate the shortest 'percentile delay' path.
DA - 2011/3//
PY - 2011/3//
DO - 10.1109/lcomm.2011.011011.102143
VL - 15
IS - 3
SP - 346-348
SN - 1089-7798
KW - Adding percentiles
KW - Erlang
KW - two-stage Coxian
KW - quality of service
KW - hypoexponential
KW - shortest path calculation
ER -
TY - JOUR
TI - A Dynamic Recursive Unified Internet Design (DRUID)
AU - Touch, Joe
AU - Baldine, Ilia
AU - Dutta, Rudra
AU - Finn, Gregory G.
AU - Ford, Bryan
AU - Jordan, Scott
AU - Massey, Dan
AU - Matta, Abraham
AU - Papadopoulos, Christos
AU - Reiher, Peter
AU - Rouskas, George
T2 - COMPUTER NETWORKS
AB - The Dynamic Recursive Unified Internet Design (DRUID) is a future Internet design that unifies overlay networks with conventional layered network architectures. DRUID is based on the fundamental concept of recursion, enabling a simple and direct network architecture that unifies the data, control, management, and security aspects of the current Internet, leading to a more trustworthy network. DRUID’s architecture is based on a single recursive block that can adapt to support a variety of communication functions, including parameterized mechanisms for hard/soft state, flow and congestion control, sequence control, fragmentation and reassembly, compression, encryption, and error recovery. This recursion is guided by the structure of a graph of translation tables that help compartmentalize the scope of various functions and identifier spaces, while relating these spaces for resource discovery, resolution, and routing. The graph also organizes persistent state that coordinates behavior between individual data events (e.g., coordinating packets as a connection), among different associations (e.g., between connections), as well as helping optimize the recursive discovery process through caching, and supporting prefetching and distributed pre-coordination. This paper describes the DRUID architecture composed of these three parts (recursive block, translation tables, persistent state), and highlights its goals and benefits, including unifying the data, control, management, and security planes currently considered orthogonal aspects of network architecture.
DA - 2011/3/10/
PY - 2011/3/10/
DO - 10.1016/j.comnet.2010.12.016
VL - 55
IS - 4
SP - 919-935
SN - 1872-7069
KW - Network architecture
KW - Future internet
KW - Recursive networks
KW - Dynamic stacks
ER -
TY - JOUR
TI - Toward robust multi-hop data forwarding in large scale wireless networks
AU - Xing, Fei
AU - Wang, Wenye
T2 - COMPUTER NETWORKS
AB - Design of robust network topology is an essential issue in large-scale multi-hop wireless networks since data packets are forwarded through intermediate nodes between source and destination, especially in the presence of non-cooperative nodes. Traditionally, topology design aims at generating network topology with high node degree, maximum throughput, and mitigation of malicious attacks. In this paper, we formulate a novel topology control problem as achieving optimal topology which maximizes network robustness against data forwarding distortion (DFD) in which a relay node may be compliant in route discovery, but drop or delay packets as non-cooperative nodes. Such node misbehavior can degrade network performance dramatically, without being detected by routing protocols and countermeasures. Therefore, we propose to design a network topology and data forwarding algorithms, namely PROACtive, in order to distribute data packets among cooperative nodes only, subject to k-connectivity constraint. Through analysis and simulations, we show that there exists a trade-off between achieving network robustness and k-connected with high probability (w.h.p.). By using distributed measurement schemes, data packets can be forwarded with low message complexity Θ(N), and improves network goodput significantly in different network scenarios.
DA - 2011/8/4/
PY - 2011/8/4/
DO - 10.1016/j.comnet.2011.04.014
VL - 55
IS - 11
SP - 2608-2621
SN - 1872-7069
KW - Multi-hop routing
KW - Network robustness
KW - Wireless networks
KW - Performance evaluation
ER -
TY - JOUR
TI - RANK-DEFICIENT NONLINEAR LEAST SQUARES PROBLEMS AND SUBSET SELECTION
AU - Ipsen, I. C. F.
AU - Kelley, C. T.
AU - Pope, S. R.
T2 - SIAM JOURNAL ON NUMERICAL ANALYSIS
AB - We examine the local convergence of the Levenberg–Marquardt method for the solution of nonlinear least squares problems that are rank-deficient and have nonzero residual. We show that replacing the Jacobian by a truncated singular value decomposition can be numerically unstable. We recommend instead the use of subset selection. We corroborate our recommendations by perturbation analyses and numerical experiments.
DA - 2011///
PY - 2011///
DO - 10.1137/090780882
VL - 49
IS - 3
SP - 1244-1266
SN - 0036-1429
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79960422161&partnerID=MN8TOARS
KW - nonlinear least squares
KW - Levenberg-Marquardt algorithm
KW - subset selection
KW - singular value decomposition
ER -
TY - JOUR
TI - Prioritising production and engineering lots in wafer fabrication facilities: a simulation study
AU - Crist, Kristy
AU - Uzsoy, Reha
T2 - INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH
AB - Due to the high cost of equipment, most semiconductor wafer fabrication facilities process both regular production lots which are shipped to customers and engineering lots that support product and process development efforts. The different objectives of the engineering and production organisations render the problem of allocating equipment capacity between these different types of lots a difficult and often contentious problem. In this paper we explore the impacts of several different policies for allocating resources to production and engineering work on the shop floor using a scaled-down simulation model of a wafer fabrication facility. Our results indicate that the availability and flexibility of engineering resources can affect the performance of scheduling policies in quite different ways. We conclude that this problem needs to be viewed in a broader context than that of a shop floor scheduling issue, including the level of available engineering resources, their degree of cross-training and the manner in which engineers are allocated to different projects.
DA - 2011///
PY - 2011///
DO - 10.1080/00207541003801259
VL - 49
IS - 11
SP - 3105-3125
SN - 1366-588X
KW - semiconductor manufacturing
KW - water fabrication
KW - production scheduling
KW - engineering
ER -
TY - JOUR
TI - Anomalous Loss Performance for Mixed Real-Time and TCP Traffic in Routers With Very Small Buffers
AU - Vishwanath, Arun
AU - Sivaraman, Vijay
AU - Rouskas, George N.
T2 - IEEE-ACM TRANSACTIONS ON NETWORKING
AB - In the past few years there has been vigorous debate regarding the size of buffers required at core Internet routers. Recent arguments supported by theory and experimentation show that under certain conditions, core router buffer sizes of a few tens of packets suffice for realizing acceptable end-to-end TCP throughputs. This is a significant step toward the realization of optical packet switched (OPS) networks, which are inherently limited in their ability to buffer optical signals. However, prior studies have largely ignored the presence of real-time traffic, which is increasing in importance as a source of revenue for Internet service providers. In this paper, we study the interaction that happens between real-time (open-loop) and TCP (closed-loop) traffic when they multiplex at buffers of very small size (few tens of packets) and make a significant discovery - namely that in a specific range of buffer size, real-time traffic losses increase as buffer size becomes larger. Our contributions pertaining to this anomalous behavior are threefold. First, we exhibit this anomalous loss performance for real-time traffic via extensive simulations using synthetic traffic and real video traces. Second, we develop quantitative models that reveal the dynamics of buffer sharing between real-time and TCP traffic that lead to this behavior. Third, we show how various factors such as the nature of real-time traffic, mixture of long-lived and short-lived TCP flows, and packet sizes impact the severity of the anomaly. Our study is the first to consider interactions between real-time and TCP traffic in very small (potentially all-optical) buffers and informs router manufacturers and network operators of the factors to consider when dimensioning such small buffer sizes for desired performance balance between real-time and TCP traffic.
DA - 2011/8//
PY - 2011/8//
DO - 10.1109/tnet.2010.2091721
VL - 19
IS - 4
SP - 933-946
SN - 1558-2566
KW - Anomalous loss performance
KW - mixed TCP and real-time traffic
KW - optical packet switched (OPS) networks
KW - routers with very small buffers
ER -
TY - JOUR
TI - A REGULARIZATION PARAMETER FOR NONSMOOTH TIKHONOV REGULARIZATION
AU - Ito, Kazufumi
AU - Jin, Bangti
AU - Takeuchi, Tomoya
T2 - SIAM JOURNAL ON SCIENTIFIC COMPUTING
AB - In this paper we develop a novel rule for choosing regularization parameters in nonsmooth Tikhonov functionals. It is solely based on the value function and applicable to a broad range of nonsmooth models, and it extends one known criterion. A posteriori error estimates of the approximations are derived. An efficient numerical algorithm for computing the minimizer is developed, and its convergence properties are discussed. Numerical results for several common nonsmooth models are presented, including deblurring natural images. The numerical results indicate the rule can yield results comparable with those achieved with the discrepancy principle and the optimal choice, and the algorithm merits a fast and steady convergence.
DA - 2011///
PY - 2011///
DO - 10.1137/100790756
VL - 33
IS - 3
SP - 1415-1438
SN - 1095-7197
KW - regularization parameter
KW - nonsmooth functional
KW - value function
KW - error estimate
ER -
TY - JOUR
TI - Using a mathematical programming model to examine the marginal price of capacitated resources
AU - Kefeli, Ali
AU - Uzsoy, Reha
AU - Fathi, Yahya
AU - Kay, Michael
T2 - INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS
AB - Accurate information on dual prices of capacitated resources is of interest in a number of applications, such as cost allocation and pricing. To gain insight we focus on the dual prices of capacity and demand in a single-stage single-product production-inventory system, and discuss their interpretation. In particular, we examine the behavior of two different production planning models: a conventional linear programming model and a nonlinear model that captures queuing behavior at resources in an aggregate manner using nonlinear clearing functions. The classical linear programming formulation consistently underestimates the dual price of capacity due to its failure to capture the effects of queuing. The clearing function formulation, in contrast, produces positive dual prices even when utilization is below one and exhibits more realistic behavior, such as holding finished inventory at utilization levels below one.
DA - 2011/5//
PY - 2011/5//
DO - 10.1016/j.ijpe.2010.03.018
VL - 131
IS - 1
SP - 383-391
SN - 1873-7579
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79952613605&partnerID=MN8TOARS
KW - Production planning
KW - Linear programming
KW - Clearing functions
KW - Dual prices
KW - Marginal prices
ER -
TY - JOUR
TI - QoS routing across multiple autonomous systems using the path computation element architecture
AU - Geleji, Geza
AU - Perros, Harry G.
T2 - ANNALS OF TELECOMMUNICATIONS
DA - 2011/6//
PY - 2011/6//
DO - 10.1007/s12243-010-0206-y
VL - 66
IS - 5-6
SP - 293-306
SN - 1958-9395
KW - BGP
KW - QoS
KW - PCE
KW - AS-path calculation algorithm
ER -
TY - CONF
TI - Methodology for engineering affective social applications
AU - Sollenberger, D. J.
AU - Singh, M. P.
C2 - 2011///
C3 - Agent-oriented software engineering x
DA - 2011///
VL - 6038
SP - 97-109
ER -
TY - JOUR
TI - MINIMAL INVASION: AN OPTIMAL L-infinity STATE CONSTRAINT PROBLEM
AU - Clason, Christian
AU - Ito, Kazufumi
AU - Kunisch, Karl
T2 - ESAIM-MATHEMATICAL MODELLING AND NUMERICAL ANALYSIS-MODELISATION MATHEMATIQUE ET ANALYSE NUMERIQUE
AB - In this work, the least pointwise upper and/or lower bounds on the state variable on a specified subdomain of a control system under piecewise constant control action are sought. This results in a non-smooth optimization problem in function spaces. Introducing a Moreau-Yosida regularization of the state constraints, the problem can be solved using a superlinearly convergent semi-smooth Newton method. Optimality conditions are derived, convergence of the Moreau-Yosida regularization is proved, and well-posedness and superlinear convergence of the Newton method is shown. Numerical examples illustrate the features of this problem and the proposed approach.
DA - 2011///
PY - 2011///
DO - 10.1051/m2an/2010064
VL - 45
IS - 3
SP - 505-522
SN - 0764-583X
KW - Optimal control
KW - optimal L-infinity state constraint
KW - semi-smooth Newton method
ER -
TY - JOUR
TI - FINDING A STABLE SOLUTION OF A SYSTEM OF NONLINEAR EQUATIONS ARISING FROM DYNAMIC SYSTEMS
AU - Kelley, Carl T.
AU - Qi, Liqun
AU - Tong, Xiaojiao
AU - Yin, Hongxia
T2 - JOURNAL OF INDUSTRIAL AND MANAGEMENT OPTIMIZATION
AB - In this paper, we present a new approach for finding a stablesolution of a system of nonlinear equations arising from dynamicalsystems. We introduce the concept ofstability functions and use this idea to constructstability solution models of severaltypical small signal stability problems in dynamical systems.Each model consists of a system of constrainedsemismooth equations. The advantage of the new models is twofold.Firstly, the stability requirement of dynamical systems iscontrolled by nonlinear inequalities. Secondly, the semismoothnessproperty of the stability functions makes the models solvable byefficient numerical methods. We introduce smoothing functions forthe stability functions and present a smoothing Newton methodfor solving the problems. Global and local quadratic convergence ofthe algorithm is established. Numerical examples from dynamicalsystems are also given to illustrate the efficiency of the newapproach.
DA - 2011/5//
PY - 2011/5//
DO - 10.3934/jimo.2011.7.497
VL - 7
IS - 2
SP - 497-521
SN - 1553-166X
KW - System of nonlinear equations
KW - stable solutions
KW - saddle-node bifurcation
KW - Hopf bifurcation
KW - stability functions
KW - smoothing Newton method
ER -
TY - JOUR
TI - The IIM in polar coordinates and its application to electro capacitance tomography problems
AU - Ruiz Alvarez, Juan
AU - Chen, Jinru
AU - Li, Zhilin
T2 - NUMERICAL ALGORITHMS
DA - 2011/7//
PY - 2011/7//
DO - 10.1007/s11075-010-9436-3
VL - 57
IS - 3
SP - 405-423
SN - 1572-9265
KW - Immersed interface method
KW - Polar coordinates
KW - Interface
KW - Discontinuous coefficients
KW - Finite difference method
KW - Electro capacitance tomography
KW - Forward problem
ER -
TY - JOUR
TI - Set covering-based surrogate approach for solving sup-T equation constrained optimization problems
AU - Hu, Cheng-Feng
AU - Fang, Shu-Cherng
T2 - FUZZY OPTIMIZATION AND DECISION MAKING
DA - 2011/6//
PY - 2011/6//
DO - 10.1007/s10700-011-9099-0
VL - 10
IS - 2
SP - 125-152
SN - 1573-2908
KW - Fuzzy relational equations
KW - Triangular norms
KW - Fuzzy optimization
KW - Set covering problems
ER -
TY - JOUR
TI - Self-Renewing Applications
AU - Singh, Munindar P.
T2 - IEEE INTERNET COMPUTING
AB - Software practice has suffered from and continues to suffer from many shortcomings as a result. Programs are difficult to design and build; they often fail to satisfy user requirements. If they work adequately at all, it's more often due to users adapting to the program than the program meeting users' requirements. The thesis of this column is that software engineering would be well served if we began to think of application-as-use as primary. In particular, if we could develop user interactions correctly, the application-as-use of a software artifact would help renew that artifact.
DA - 2011///
PY - 2011///
DO - 10.1109/mic.2011.95
VL - 15
IS - 4
SP - 3-5
SN - 1941-0131
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79959988653&partnerID=MN8TOARS
ER -
TY - JOUR
TI - On the unique solvability of fuzzy relational equations
AU - Li, Pingke
AU - Fang, Shu-Cherng
T2 - FUZZY OPTIMIZATION AND DECISION MAKING
DA - 2011/6//
PY - 2011/6//
DO - 10.1007/s10700-011-9100-y
VL - 10
IS - 2
SP - 115-124
SN - 1573-2908
KW - Fuzzy relational equations
KW - Minimal solutions
KW - Unique solvability
ER -
TY - JOUR
TI - Identifiability of the proportion of null hypotheses in skew-mixture models for the p-value distribution
AU - Ghosal, S.
AU - Roy, A.
T2 - Electronic Journal of Statistics
DA - 2011///
PY - 2011///
VL - 5
SP - 329-341
ER -
TY - JOUR
TI - High order compact finite difference schemes for the helmholtz equation with discontinuous coefficients
AU - Feng, X. F.
AU - Li, Z. L.
AU - Qiao, Z. H.
T2 - Journal of Computational Mathematics
DA - 2011///
PY - 2011///
VL - 29
IS - 3
SP - 324-340
ER -
TY - JOUR
TI - ERGODICITY COEFFICIENTS DEFINED BY VECTOR NORMS
AU - Ipsen, Ilse C. F.
AU - Selee, Teresa M.
T2 - SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS
AB - Ergodicity coefficients for stochastic matrices determine inclusion regions for subdominant eigenvalues; estimate the sensitivity of the stationary distribution to changes in the matrix; and bound the convergence rate of methods for computing the stationary distribution. We survey results for ergodicity coefficients that are defined by p-norms, for stochastic matrices as well as for general real or complex matrices. We express ergodicity coefficients in the one-, two-, and infinity-norms as norms of projected matrices, and we bound coefficients in any p-norm by norms of deflated matrices. We show that two-norm ergodicity coefficients of a matrix A are closely related to the singular values of A. In particular, the singular values determine the extreme values of the coefficients. We show that ergodicity coefficients can determine inclusion regions for subdominant eigenvalues of complex matrices, and that the tightness of these regions depends on the departure of the matrix from normality. In the special case of normal matrices, two-norm ergodicity coefficients turn out to be Lehmann bounds.
DA - 2011///
PY - 2011///
DO - 10.1137/090752948
VL - 32
IS - 1
SP - 153-200
SN - 1095-7162
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84875120748&partnerID=MN8TOARS
KW - singular values
KW - eigenvalues
KW - stochastic matrices
KW - nonnegative matrices
KW - inclusion regions
KW - projections
ER -
TY - JOUR
TI - COMPUTING CHARACTERISTIC POLYNOMIALS FROM EIGENVALUES
AU - Rehman, Rizwana
AU - Ipsen, Ilse C. F.
T2 - SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS
AB - This paper concerns the computation of the coefficients $c_k$ of the characteristic polynomial of a real or complex matrix A. We analyze the forward error in the coefficients $c_k$ when they are computed from the eigenvalues of A, as is done by MATLAB's poly function. In particular, we derive absolute and relative perturbation bounds for elementary symmetric functions, which we use in turn to derive perturbation bounds for the coefficients $c_k$ with regard to absolute and relative changes in the eigenvalues $\lambda_j$ of A. We present the so-called Summation Algorithm for computing the coefficients $c_k$ from the eigenvalues $\lambda_j$, which is essentially the algorithm used by poly. We derive roundoff error bounds and running error bounds for the Summation Algorithm. The roundoff error bounds imply that the Summation Algorithm is forward stable. The running error bounds can be used to estimate the accuracy of the computed coefficients “on the fly,” and they tend to be less pessimistic than the roundoff error bounds. Numerical experiments illustrate that our bounds give useful estimates for the accuracy of the coefficients $c_k$. In particular, the bounds confirm that poly computes the coefficients $c_k$ to high relative accuracy if the eigenvalues are positive and given to high relative accuracy.
DA - 2011///
PY - 2011///
DO - 10.1137/100788392
VL - 32
IS - 1
SP - 90-114
SN - 0895-4798
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79952367119&partnerID=MN8TOARS
KW - elementary symmetric functions
KW - perturbation bounds
KW - roundoff error bounds
KW - determinant
ER -
TY - JOUR
TI - Adaptive mesh refinement for elliptic interface problems using the non-conforming immersed finite element method
AU - Wu, C. T.
AU - Li, Z. L.
AU - Lai, M. C.
T2 - International Journal of Numerical Analysis and Modeling
DA - 2011///
PY - 2011///
VL - 8
IS - 3
SP - 466-483
ER -
TY - JOUR
TI - A practical fair queuing scheduler: Simplification through quantization
AU - Dwekat, Z.
AU - Rouskas, G. N.
T2 - COMPUTER NETWORKS
AB - The design of fair packet schedulers involves a tradeoff between implementation complexity, on one hand, and delay and fairness guarantees, on the other. In this paper, we present tiered-service fair queuing (TSFQ), a new scheduler that exploits certain properties of Internet traffic to speed up the bottleneck operations related to virtual time computation and packet sorting. Specifically, TSFQ makes innovative use of quantization (along the two dimensions of flow weights and packet lengths) her with specialized yet simple queuing structures. TSFQ combines all three properties that are important to a fair queuing algorithm, namely, a tight delay bound, worst-case fairness, and low complexity and amenability to hardware implementation. Hence, we believe that, for network operators, deploying TSFQ scheduling has the potential to enhance their ability to offer and guarantee a wide range of services.
DA - 2011/7/14/
PY - 2011/7/14/
DO - 10.1016/j.comnet.2011.04.004
VL - 55
IS - 10
SP - 2392-2406
SN - 1872-7069
KW - Packet scheduling
KW - Fair queuing
KW - Tiered service
ER -
TY - JOUR
TI - Online algorithms for advance resource reservations
AU - Castillo, C.
AU - Rouskas, G. N.
AU - Harfoush, K.
T2 - JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING
AB - We consider the problem of providing QoS guarantees to Grid users through advance reservation of resources. Advance reservation mechanisms provide the ability to allocate resources to users based on agreed-upon QoS requirements and increase the predictability of a Grid system, yet incorporating such mechanisms into current Grid environments has proven to be a challenging task due to the resulting resource fragmentation. We use concepts from computational geometry to present a framework for tackling the resource fragmentation, and for formulating a suite of scheduling strategies. We also develop efficient implementations of the scheduling algorithms that scale to large Grids. We conduct a comprehensive performance evaluation study using simulation, and we present numerical results to demonstrate that our strategies perform well across several metrics that reflect both user- and system-specific goals. Our main contribution is a timely, practical, and efficient solution to the problem of scheduling resources in emerging on-demand computing environments.
DA - 2011/7//
PY - 2011/7//
DO - 10.1016/j.jpdc.2011.01.003
VL - 71
IS - 7
SP - 963-973
SN - 1096-0848
KW - Grid computing
KW - Advance reservations
KW - Scheduling
KW - Resource allocation
KW - Resource management
ER -
TY - JOUR
TI - Note on 'Influences of Resource Limitations and Transmission Costs on Epidemic Simulations and Critical Thresholds in Scale-Free Networks'
AU - Wilson, James R.
T2 - SIMULATION-TRANSACTIONS OF THE SOCIETY FOR MODELING AND SIMULATION INTERNATIONAL
AB - In a recent paper entitled ‘Influences of Resource Limitations and Transmission Costs on Epidemic Simulations and Critical Thresholds in Scale-Free Networks’ by Huang et al., the authors attempted to establish a key characteristic of epidemic dynamics in a scale-free network when properly accounting for the cost of transmitting the infection at each node and the resources available for transmission to that node. The main input parameter is the effective rate of spreading the infection, i.e. the instantaneous rate at which the infection is spread to an uninfected node via a single link to an infected node. The primary result is the existence of a positive critical threshold for the infection-spreading rate at or below which the epidemic dies out and above which the epidemic is spread through the network and ultimately reaches a steady-state non-vanishing condition. Some flaws in the authors’ proof of this result are discussed, and an alternative derivation is provided that sheds additional light on the transient and steady-state behavior of the system. The alternative derivation may be adapted to the analysis of other scale-free networks with different features.
DA - 2011/3//
PY - 2011/3//
DO - 10.1177/0037549710366018
VL - 87
IS - 3
SP - 262-266
SN - 0037-5497
KW - scale-free networks
KW - epidemic simulation
ER -
TY - JOUR
TI - Efficient Parallel Computation of Molecular Potential Energy Surfaces for the Study of Light-Induced Transition Dynamics in Multiple Coordinates
AU - Mokrauer, David
AU - Kelley, C. T.
AU - Bykhovski, Alexei
T2 - IEEE TRANSACTIONS ON NANOTECHNOLOGY
AB - The conformational dynamics of molecules that arise due to light-induced transitions are critically important in many biochemical reactions, and therefore dictate the functionality of many types of biological sensors. Therefore, researchers of biological science and biological-inspired technology often need to prescribe the molecular geometry of the stable states and the associated transition trajectories that occur as a result of external excitation, e.g., light-induced transitions from the ground state to the excited states. The traditional approach to study this type of phenomenology is to limit the number of varying molecular coordinates to one or a few due to the considerable computational expense of the required physically modeling required for generating an accurate physical model for analysis. While the conformational dynamics for some types of simple molecules (e.g., retinal) are known to be adequately described by one or few numbers of molecular coordinates, light-induced transitions in arbitrarily complex molecules can be expected to involve the influence of multiple coordinates, and their influence can be expected to vary as a function of time. The research reported here will address the development of parallel computational algorithms that allow for the highly efficient study of molecular conformational dynamics over multiple numbers of multidimensional energy surfaces. Here, the goal is the development of a simulation tool that is capable of: constructing physically accurate multidimensional potential energy surfaces (i.e., from first-principle physical modeling codes); deriving the natural trajectories to local minima within individual surfaces; and that allows for dynamics human interfacing for specifying the transition between energy surfaces and the number of coordinates to be used for the optimization within a particular energy surface. As will be illustrated, this type of physics-based simulation tool will allow researchers to efficiently explore the light-induced conformation dynamics associated with complex biomolecules, and therefore, be a useful tool for the design of biological-sensing processes in the future.
DA - 2011/1//
PY - 2011/1//
DO - 10.1109/tnano.2010.2058862
VL - 10
IS - 1
SP - 70-74
SN - 1941-0085
KW - Algorithm design and analysis
KW - chemical sensors
KW - 1H NMR
KW - nanoelectonics
KW - stibenes
KW - UV-vis spectroscopy
ER -
TY - JOUR
TI - An active index algorithm for the nearest point problem in a polyhedral cone
AU - Liu, Zhe
AU - Fathi, Yahya
T2 - COMPUTATIONAL OPTIMIZATION AND APPLICATIONS
DA - 2011/7//
PY - 2011/7//
DO - 10.1007/s10589-009-9303-0
VL - 49
IS - 3
SP - 435-456
SN - 0926-6003
KW - Quadratic programming
KW - Pos cone
KW - Projection face
KW - Active constraint
ER -
TY - JOUR
TI - Adaptive control design for uncertain polynomial nonlinear systems with parametric uncertainties
AU - Zheng, Qian
AU - Wu, Fen
T2 - INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING
AB - In this paper, we will develop an adaptive ℋ︁∞ control approach for a class of polynomial nonlinear systems with parametric uncertainties. Motivated by the dissipation theory and the vector projection technique, we propose a nonlinear adaptive ℋ︁∞ controller and its associated parameter adaptation law. The proposed adaptive control strategy is capable of identifying unknown parameter values quickly and minimizing the effect of estimation error. To further improve adaptive controlled performance, the Lyapunov function will be relaxed from quadratic to higher-order forms and the controller gains are generalized from constant to parameter-dependent. All of the synthesis conditions are formulated in the framework of polynomial/constant linear matrix inequalities and solvable using available software packages. Copyright © 2010 John Wiley & Sons, Ltd.
DA - 2011/6//
PY - 2011/6//
DO - 10.1002/acs.1215
VL - 25
IS - 6
SP - 502-518
SN - 0890-6327
KW - uncertain nonlinear system
KW - adaptive control
KW - H-infinity performance
KW - higher-order Lyapunov function
KW - SOS programming
ER -
TY - JOUR
TI - The Limit of Information Propagation Speed in Large-Scale Multihop Wireless Networks
AU - Xu, Yi
AU - Wang, Wenye
T2 - IEEE-ACM TRANSACTIONS ON NETWORKING
AB - This paper investigates the speed limit of information propagation in large-scale multihop wireless networks, which provides fundamental understanding of the fastest information transportation and delivery that a wireless network is able to accommodate. We show that there exists a unified speed upper bound for broadcast and unicast communications in large-scale wireless networks. When network connectivity is considered, this speed bound is a function of node density. If the network noise is constant, the bound is a constant when node density exceeds a threshold; if the network noise is an increasing function of node density, the bound decreases to zero when node density approaches infinity. As achieving the speed bound places strict requirements on node locations, we also quantify the gap between the actual achieved speed and the desired bound in random networks in which the relay nodes are not located as desired. We find that the gap converges to zero exponentially as node density increases to infinity.
DA - 2011/2//
PY - 2011/2//
DO - 10.1109/tnet.2010.2057444
VL - 19
IS - 1
SP - 209-222
SN - 1558-2566
KW - Information propagation
KW - multihop communication
KW - network connectivity
KW - packet delay
KW - wireless network
ER -
TY - JOUR
TI - High-Confidence Discovery of Genetic Network Regulators in Expression Quantitative Trait Loci Data
AU - Duarte, Christine W.
AU - Zeng, Zhao-Bang
T2 - GENETICS
AB - Abstract Expression QTL (eQTL) studies involve the collection of microarray gene expression data and genetic marker data from segregating individuals in a population to search for genetic determinants of differential gene expression. Previous studies have found large numbers of trans-regulated genes (regulated by unlinked genetic loci) that link to a single locus or eQTL “hotspot,” and it would be desirable to find the mechanism of coregulation for these gene groups. However, many difficulties exist with current network reconstruction algorithms such as low power and high computational cost. A common observation for biological networks is that they have a scale-free or power-law architecture. In such an architecture, highly influential nodes exist that have many connections to other nodes. If we assume that this type of architecture applies to genetic networks, then we can simplify the problem of genetic network reconstruction by focusing on discovery of the key regulatory genes at the top of the network. We introduce the concept of “shielding” in which a specific gene expression variable (the shielder) renders a set of other gene expression variables (the shielded genes) independent of the eQTL. We iteratively build networks from the eQTL to the shielder down using tests of conditional independence. We have proposed a novel test for controlling the shielder false-positive rate at a predetermined level by requiring a threshold number of shielded genes per shielder. Using simulation, we have demonstrated that we can control the shielder false-positive rate as well as obtain high shielder and edge specificity. In addition, we have shown our method to be robust to violation of the latent variable assumption, an important feature in the practical application of our method. We have applied our method to a yeast expression QTL data set in which microarray and marker data were collected from the progeny of a backcross of two species of Saccharomyces cerevisiae (Bremet al. 2002). Seven genetic networks have been discovered, and bioinformatic analysis of the discovered regulators and corresponding regulated genes has generated plausible hypotheses for mechanisms of regulation that can be tested in future experiments.
DA - 2011/3//
PY - 2011/3//
DO - 10.1534/genetics.110.124685
VL - 187
IS - 3
SP - 955-964
SN - 0016-6731
ER -
TY - JOUR
TI - Adapting lean manufacturing principles to the textile industry
AU - Hodge, G.L.
AU - Ross, K.G.
AU - Joines, J.A.
AU - Thoney, K.A.
T2 - Production Planning & Control Special Issue on Challenges in Apparel Production, Planning and Control
AB - A research project was conducted to determine which lean principles are appropriate for implementation in the textile industry. Lean manufacturing involves a variety of principles and techniques, all of which have the same ultimate goal: to eliminate waste and non-value-added activities at every production or service process in order to give the most satisfaction to the customer. To stay competitive, many US textile manufacturers have sought to improve their manufacturing processes so that they can more readily compete with overseas manufacturers. This study identifies the different tools and principles of lean. The use of lean manufacturing in the textile industry was examined in this research through interviews, plant tours and case studies. A model for implementing lean tools and principles in a textile environment was developed.
DA - 2011///
PY - 2011///
DO - 10.1080/09537287.2010.498577
VL - 22
IS - 3
SP - 237–247
SN - 0953-7287
KW - lean manufacturing
KW - textiles
KW - value stream mapping
ER -
TY - JOUR
TI - The effect of shop floor continuous improvement programs on the lot size-cycle time relationship in a multi-product single-machine environment
AU - Godinho Filho, Moacir
AU - Uzsoy, Reha
T2 - INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
DA - 2011/2//
PY - 2011/2//
DO - 10.1007/s00170-010-2770-8
VL - 52
IS - 5-8
SP - 669-681
SN - 1433-3015
KW - Lot size
KW - Cycle time
KW - Continuous improvement
KW - System dynamics
KW - Factory physics
KW - Multi-product single-machine environment
ER -
TY - JOUR
TI - N-Skart: A Nonsequential Skewness- and Autoregression-Adjusted Batch-Means Procedure for Simulation Analysis
AU - Tafazzoli, Ali
AU - Steiger, Natalie M.
AU - Wilson, James R.
T2 - IEEE TRANSACTIONS ON AUTOMATIC CONTROL
AB - We discuss N-Skart, a nonsequential procedure designed to deliver a confidence interval (CI) for the steady-state mean of a simulation output process when the user supplies a single simulation-generated time series of arbitrary size and specifies the required coverage probability for a CI based on that data set. N-Skart is a variant of the method of batch means that exploits separate adjustments to the half-length of the CI so as to account for the effects on the distribution of the underlying Student's *t* -statistic that arise from skewness (nonnormality) and autocorrelation of the batch means. If the sample size is sufficiently large, then N-Skart delivers not only a CI but also a point estimator for the steady-state mean that is approximately free of initialization bias. In an experimental performance evaluation involving a wide range of test processes and sample sizes, N-Skart exhibited close conformance to the user-specified CI coverage probabilities.
DA - 2011/2//
PY - 2011/2//
DO - 10.1109/tac.2010.2052137
VL - 56
IS - 2
SP - 254-264
SN - 1558-2523
KW - Autoregressive representation
KW - confidence interval (CI)
KW - Cornish-Fisher expansion
KW - method of batch means
KW - simulation
KW - statistical analysis
KW - steady-state analysis
ER -
TY - JOUR
TI - A finite element method for elasticity interface problems with locally modified triangulations
AU - Xie, H.
AU - Li, Z. L.
AU - Qiao, Z. H.
T2 - International Journal of Numerical Analysis and Modeling
DA - 2011///
PY - 2011///
VL - 8
IS - 2
SP - 189-200
ER -
TY - JOUR
TI - A Probabilistic Approach for Maintaining Trust Based on Evidence
AU - Wang, Yonghong
AU - Hang, Chung-Wei
AU - Singh, Munindar P.
T2 - JOURNAL OF ARTIFICIAL INTELLIGENCE RESEARCH
AB - Leading agent-based trust models address two important needs. First, they show how an agent may estimate the trustworthiness of another agent based on prior interactions. Second, they show how agents may share their knowledge in order to cooperatively assess the trustworthiness of others. However, in real-life settings, information relevant to trust is usually obtained piecemeal, not all at once. Unfortunately, the problem of maintaining trust has drawn little attention. Existing approaches handle trust updates in a heuristic, not a principled, manner. This paper builds on a formal model that considers probability and certainty as two dimensions of trust. It proposes a mechanism using which an agent can update the amount of trust it places in other agents on an ongoing basis. This paper shows via simulation that the proposed approach (a) provides accurate estimates of the trustworthiness of agents that change behavior frequently; and (b) captures the dynamic behavior of the agents. This paper includes an evaluation based on a real dataset drawn from Amazon Marketplace, a leading e-commerce site.
DA - 2011///
PY - 2011///
DO - 10.1613/jair.3108
VL - 40
SP - 221-267
SN - 1943-5037
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79956343086&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Trustworthy Service Selection and Composition
AU - Hang, Chung-Wei
AU - Singh, Munindar P.
T2 - ACM Transactions on Autonomous and Adaptive Systems
AB - We consider Service-Oriented Computing (SOC) environments. Such environments are populated with services that stand proxy for a variety of information resources. A fundamental challenge in SOC is to select and compose services, to support specified user needs directly or by providing additional services. Existing approaches for service selection either fail to capture the dynamic relationships between services or assume that the environment is fully observable. In practical situations, however, consumers are often not aware of how the services are implemented. We propose two distributed trust-aware service selection approaches: one based on Bayesian networks and the other on a beta-mixture model. We experimentally validate our approach through a simulation study. Our results show that both approaches accurately punish and reward services in terms of the qualities they offer, and further that the approaches are effective despite incomplete observations regarding the services under consideration.
DA - 2011/2/1/
PY - 2011/2/1/
DO - 10.1145/1921641.1921646
VL - 6
IS - 1
SP - 1-17
J2 - ACM Trans. Auton. Adapt. Syst.
LA - en
OP -
SN - 1556-4665
UR - http://dx.doi.org/10.1145/1921641.1921646
DB - Crossref
KW - Algorithms
KW - Experimentation
KW - Trust
KW - probabilistic modeling
KW - service-oriented computing
ER -
TY - JOUR
TI - Skart: A skewness- and autoregression-adjusted batch-means procedure for simulation analysis
AU - Tafazzoli, Ali
AU - Wilson, James R.
T2 - IIE TRANSACTIONS
AB - Skart is an automated sequential batch-means procedure for constructing a skewness- and autoregression-adjusted confidence interval (CI) for the steady-state mean of a simulation output process either in discrete time (i.e., using observation-based statistics), or in continuous time (i.e., using time-persistent statistics). Skart delivers a CI designed to satisfy user-specified requirements concerning both the CI's coverage probability and its absolute or relative precision. Skart exploits separate adjustments to the classical batch-means CI to account for the effects on the distribution of the underlying Student's t-statistic arising from skewness and autocorrelation of the batch means. The skewness adjustment is based on a Cornish–Fisher expansion for the classical batch-means t-statistic, and the autocorrelation adjustment is based on a first-order autoregressive approximation to the batch-means autocorrelation function. Skart also delivers a point estimator for the steady-state mean that is approximat...
DA - 2011///
PY - 2011///
DO - 10.1080/0740817x.2010.504688
VL - 43
IS - 2
SP - 110-128
SN - 0740-817X
KW - Simulation
KW - statistical analysis
KW - steady-state analysis
KW - method of batch means
KW - Cornish-Fisher expansion
KW - autoregressive representation
ER -
TY - JOUR
TI - Glycine and a Glycine Dehydrogenase (GLDC) SNP as Citalopram/Escitalopram Response Biomarkers in Depression: Pharmacometabolomics-Informed Pharmacogenomics
AU - Ji, Y.
AU - Hebbring, S.
AU - Zhu, H.
AU - Jenkins, G. D.
AU - Biernacka, J.
AU - Snyder, K.
AU - Drews, M.
AU - Fiehn, O.
AU - Zeng, Z.
AU - Schaid, D.
AU - Mrazek, D. A.
AU - Kaddurah-Daouk, R.
AU - Weinshilboum, R. M.
T2 - CLINICAL PHARMACOLOGY & THERAPEUTICS
AB - Major depressive disorder (MDD) is a common psychiatric disease. Selective serotonin reuptake inhibitors (SSRIs) are an important class of drugs used in the treatment of MDD. However, many patients do not respond adequately to SSRI therapy. We used a pharmacometabolomics-informed pharmacogenomic research strategy to identify citalopram/escitalopram treatment outcome biomarkers. Metabolomic assay of plasma samples from 20 escitalopram remitters and 20 nonremitters showed that glycine was negatively associated with treatment outcome (P = 0.0054). This observation was pursued by genotyping tag single-nucleotide polymorphisms (SNPs) for genes encoding glycine synthesis and degradation enzymes, using 529 DNA samples from SSRI-treated MDD patients. The rs10975641 SNP in the glycine dehydrogenase (GLDC) gene was associated with treatment outcome phenotypes. Genotyping for rs10975641 was carried out in 1,245 MDD patients in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, and its presence was significant (P = 0.02) in DNA taken from these patients. These results highlight a possible role for glycine in SSRI response and illustrate the use of pharmacometabolomics to “inform” pharmacogenomics. Clinical Pharmacology & Therapeutics (2011) 89 1, 97–104. doi: 10.1038/clpt.2010.250
DA - 2011/1//
PY - 2011/1//
DO - 10.1038/clpt.2010.250
VL - 89
IS - 1
SP - 97-104
SN - 1532-6535
ER -
TY - JOUR
TI - Multiobjective fault detection and isolation for flexible air-breathing hypersonic vehicle
AU - Cai, Xuejing
AU - Wu, Fen
T2 - JOURNAL OF SYSTEMS ENGINEERING AND ELECTRONICS
AB - An application of the multiobjective fault detection and isolation (FDI) approach to an air-breathing hypersonic vehicle (HSV) longitudinal dynamics subject to disturbances is presented. Maintaining sustainable and safe flight of HSV is a challenging task due to its strong coupling effects, variable operating condi- tions and possible failures of system components. A common type of system faults for aircraft including HSV is the loss of effective- ness of its actuators and sensors. To detect and isolate multiple actuator/sensor failures, a faulty linear parameter-varying (LPV) model of HSV is derived by converting actuator/system compo- nent faults into equivalent sensor faults. Then a bank of LPV FDI observers is designed to track individual fault with minimum error and suppress the effects of disturbances and other fault signals. The simulation results based on the nonlinear flexible HSV model and a nominal LPV controller demonstrate the effectiveness of the fault estimation technique for HSV.
DA - 2011/2//
PY - 2011/2//
DO - 10.3969/j.issn.1004-4132.2011.01.006
VL - 22
IS - 1
SP - 52-62
SN - 1004-4132
KW - fault detection and isolation (FDI)
KW - hypersonic vehicle (HSV)
KW - actuator and sensor faults
KW - multiobjective optimization
ER -
TY - JOUR
TI - Modeling the Effects of Sodium Chloride, Acetic Acid, and Intracellular pH on Survival of Escherichia coli O157:H7
AU - Hosein, Althea M.
AU - Breidt, Frederick, Jr.
AU - Smith, Charles E.
T2 - APPLIED AND ENVIRONMENTAL MICROBIOLOGY
AB - ABSTRACT Microbiological safety has been a critical issue for acid and acidified foods since it became clear that acid-tolerant pathogens such as Escherichia coli O157:H7 can survive (even though they are unable to grow) in a pH range of 3 to 4, which is typical for these classes of food products. The primary antimicrobial compounds in these products are acetic acid and NaCl, which can alter the intracellular physiology of E. coli O157:H7, leading to cell death. For combinations of acetic acid and NaCl at pH 3.2 (a pH value typical for non-heat-processed acidified vegetables), survival curves were described by using a Weibull model. The data revealed a protective effect of NaCl concentration on cell survival for selected acetic acid concentrations. The intracellular pH of an E. coli O157:H7 strain exposed to acetic acid concentrations of up to 40 mM and NaCl concentrations between 2 and 4% was determined. A reduction in the intracellular pH was observed for increasing acetic acid concentrations with an external pH of 3.2. Comparing intracellular pH with Weibull model predictions showed that decreases in intracellular pH were significantly correlated with the corresponding times required to achieve a 5-log reduction in the number of bacteria.
DA - 2011/2//
PY - 2011/2//
DO - 10.1128/aem.02136-10
VL - 77
IS - 3
SP - 889-895
SN - 1098-5336
ER -
TY - JOUR
TI - A selfish routing based network improvement problem
AU - Zhang, Binwu
AU - Fang, Shu-Cherng
T2 - Journal of Systems Science and Complexity
DA - 2011/2//
PY - 2011/2//
DO - 10.1007/s11424-011-8156-7
VL - 24
IS - 1
SP - 68-78
J2 - J Syst Sci Complex
LA - en
OP -
SN - 1009-6124 1559-7067
UR - http://dx.doi.org/10.1007/s11424-011-8156-7
DB - Crossref
KW - Nash equilibrium
KW - NP-hard
KW - selfish routing
KW - price of anarchy
ER -