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IEEE Globecom 2006

作者： Lillian L. Dai Vincent W. S. Chan Electrical Engineering and Computer Science Department Laboratory of Information and Decision Systems Massachusetts Institute of Technology Cambridge MA USA

It is widely believed that "whispering to the nearest neighbor" (ie. taking a large number of short hops) is the throughput optimal routing scheme for all ad-hoc wireless networks. We show that for power-limited networks where processing energy is not an insignificant factor, instead of taking short hops, there exists a characteristic hop distance that, along with load balancing, can attain high throughput, even for networks with a small number of nodes. In fact, the "whisper to the nearest neighbor" routing scheme leads to strictly suboptimal uniform throughput on the order of O(radic(inN/N)) when processing energy is considered. We show that taking thetas(1) number of hops is throughput, energy, and delay optimal, achieving thetas(1) uniform capacity under uniform traffic. These results are contrary to previous results on the capacity of power-limited wireless networks under a zero-processing energy assumption, which showed that capacity increases with increasing number of nodes. Hence, failing to account for processing energy not only leads to suboptimal routing schemes, but also leads to inflated optimism about the capacity scaling behavior of power-limited wireless networks.

关键词： Throughput Wireless networks Routing Nearest neighbor searches Load management Telecommunication traffic Ultra wideband technology Energy consumption Laboratories USA Councils

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Tourism technical analysis system

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Tourism Economics 2006年第4期12卷 543-563页

作者： Petropoulos, C. Nikolopoulos, K. Patelis, A. Assimakopoulos, V. Askounis, D. Forecasting Systems Unit School of Electrical and Computer Engineering National Technical University of Athens 15773 Zografou Athens 9 Iroon Polytechniou Str. Greece Supply Chain Management Research Group Department of Decision Sciences and Operations Management University of Manchester Manchester M15 6PB United Kingdom Ministry of Economy and Finance 10180 Athens 5-7 Nikis Str. Greece Decision Support Systems Laboratory School of Electrical and Computer Engineering National Technical University of Athens 15773 Zografou Athens 9 Iroon Polytechniou Str. Greece

Accurate forecasts of tourism demand are prerequisites in the decision making process in many organizations in the private and public sectors. Any information concerning the future evolution of tourism flows is of great importance to hoteliers, tour operators and other industries concerned with tourism, services or transportation. In the last few decades international tourism demand has attracted substantial academic interest, resulting in a wide range of successful forecasting approaches. Much attention has been paid to econometric models that use regression techniques to estimate the underlying relationship between tourism demand and its determinants;unfortunately, empirical studies suggest that these models usually fail to outperform simple time series models. The current study focuses on an alternative approach, the Tourism Technical Analysis System (TTAS), incorporating the use of technical analysis techniques and building on the similarities between stock and tourism markets. The absolute and directional accuracy of TTAS is evaluated in relation to a range of time series and econometric methods for forecasting international tourism demand, using as a benchmark well-known published research.

关键词： Forecasting Technical analysis econometric models Theta decomposition Tourism demand

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Sparsity-driven sparse-aperture ultrasound imaging

Sparsity-driven sparse-aperture ultrasound imaging

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2006 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP 2006

作者： Çetin, Müjdat Bossy, Emmanuel Cleveland, Robin Karl, W. Clem Faculty of Engineering and Natural Sciences Sabanci University Istanbul Turkey Laboratory for Information and Decision Systems MIT Cambridge MA United States Department of Aerospace and Mechanical Engineering Boston University Boston MA United States Department of Electrical and Computer Engineering Boston University Boston MA United States Laboratoire d'Optique Physique ESPCI/CNRS - UPR 5 Paris France

ISBN: (纸本)142440469X

We propose an image formation algorithm for ultrasound imaging based on sparsity-driven regularization functionals. We consider data collected by synthetic transducer arrays, with the primary motivating application being nondestructive evaluation. Our framework involves the use of a physical optics-based forward model of the observation process;the formulation of an optimization problem for image formation;and the solution of that problem through efficient numerical algorithms. Our sparsity-driven, model-based approach achieves the preservation of physical features while suppressing spurious artifacts. It also provides robust reconstructions in the case of sparse observation apertures. We demonstrate the effectiveness of our imaging strategy on real ultrasound data. © 2006 IEEE.

关键词： Ultrasonic imaging

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On Delay Performance Gains From Network Coding

On Delay Performance Gains From Network Coding

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Annual Conference on Information Sciences and systems (CISS)

作者： Atilla Eryilmaz Asuman Ozdaglar Muriel Medard Laboratory for Information and Decision Systems Massachusetts Institute of Technology Cambridge MA USA Electrical Engineering and Computer Science Department Massachusetts Institute of Technology Cambridge MA USA

This paper analyzes the gains in delay performance resulting from network coding. We consider a model of file transmission to multiple receivers from a single base station. Using this model, we show that gains in delay performance from network coding with or without channel side information can be substantial compared to conventional scheduling methods for downlink transmission.

关键词： Performance gain Network coding Optimal scheduling Performance analysis Base stations Downlink Delay Information analysis Wireless networks Wireless communication

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Joint Asynchronous Congestion control and Distributed Scheduling for Multi-Hop Wireless Networks

Joint Asynchronous Congestion Control and Distributed Schedu...

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IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： L. Bui A. Eryilmaz R. Srikant X. Wu Department of Electrical and Computer Engineering and Coordinated Science Laboratory University of Illinois Urbana-Champaign USA Laboratory for Information and Decision Systems Massachusetts Institute of Technology USA Flarion Technologies NJ USA

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Robust Finite Time control of Nonlinear systems with Dynamic Uncertainty

Robust Finite Time Control of Nonlinear Systems with Dynamic...

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American control Conference

作者： Yiguang Hong Zhong-Ping Jiang Institute of Systems Science Key Laboratory of Systems and Control Chinese Academy and Sciences Beijing China Department of Electrical and Computer Engineering Polytechnic University Brooklyn NY USA

In this paper, robust finite-time control problem of nonlinear systems with dynamic uncertainties is investigated. To solve this problem, a partial-state control design is proposed in a constructive way. With small-ga... 详细信息

ISBN: (纸本)1424402093

关键词： Lyapunov methods control system synthesis nonlinear control systems nonlinear dynamical systems robust control uncertain systems dynamic uncertainties finite time control finite-time stabilization input-to-state stability nonsmooth feedback partial-state

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Integrated information processing and communications: Complexity analysis

Integrated information processing and communications: Comple...

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IASTED International Conference on COMMUNICATION systems AND APPLICATIONS Part of the Sixth IASTED International Multi-Conference on WIRELESS AND OPTICAL COMMUNICATIONS

作者： Huyu, Qu Le, Yi Wang Yaprak, Ece Hong, Wang Yanlong, Zhao Department of Electrical and Computer Engineering Wayne State University Detroit MI 48202 United States Division of Engineering Technology Wayne State University Detroit MI 48202 United States Department of Anesthesiology Wayne State University Detroit MI 48202 United States Key Laboratory of System and Control Academy of Mathematics and Systems Science Chinese Academy of Sciences China

Accuracy of information transmission when a signal must be transmitted through a communication channel is of essential importance in design of communication systems. When system resources are limited, such as transmission bandwidths assigned to a wireless communication channel, appropriate utility of available resources becomes imperative. This paper investigates fundamental relationships between accuracy of information exchange and communication resources, on a platform of wireless communication channels that involve typical system blocks of data compression, quantization, and stochastic wireless channels. The main complexity relationships developed in this paper provide rigorous trade-off between resource consumptions and information processing errors of each block. When these relationships are integrated, an optimization procedure emerges that allows optimal allocation of resources to each system block, such as compression ratio, quantization levels, and transmission speed, to maximize overall information accuracy. Consequently, the overall errors of the transmitted signal will be minimized at the receiver end.

关键词： Data processing

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Single differential modulation and detection for MPSK in the presence of unknown frequency offset

Single differential modulation and detection for MPSK in the...

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40th Asilomar Conference on Signals, systems, and computers, ACSSC '06

作者： Liu, Jianhua Stoica, Petre Simon, Marvin Li, Jian Department of Electrical and Systems Engineering Embry-Riddle Aeronautical University Daytona Beach FL 32114 United States Department of Systems and Control Uppsala University P.O. Box 337 SE-75105 Uppsala Sweden Jet Propulsion Laboratory MS 238-343 4800 Oak Grove Drive Pasadena CA 91109 United States Department of Electrical and Computer Engineering University of Florida P.O. Box 116130 Gainesville FL 32611-6130 United States

ISBN: (纸本)1424407850

We consider improving the performance of communications over unknown channels with unknown frequency offsets. In lieu of the commonly suggested double differential (DD) modulation/detection, we consider single differential (SD) modulation/detection. We propose an approach that first estimates and compensates for the frequency offset and then detects using an existing multiple symbol detector for SD modulation. We introduce a simple data-symbol- independent frequency offset estimation method, which is reasonably accurate when using a data block larger than the one used for detection. Simulation results show that the SD modulation/detection approach proposed herein can significantly outperform the DD modulation/detection schemes.

关键词： Signal detection

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Finite-Time Stabilization and Identification of A Class of Uncertain systems

Finite-Time Stabilization and Identification of A Class of U...

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Chinese control Conference (CCC)

作者： Yiguang Hong Zhong-ping Jiang Key Laboratory of Systems anc Control Chinese Academy and Sciences Beijing China Department of Electrical and Computer Engineering Polytechnic University Brooklyn NY USA

This paper addresses finite-time stabilization and identification problems for a class of uncertain systems with unknown parameters. New finite-time control laws are constructed with a design idea based on Lyapunov fu... 详细信息

关键词： Uncertain systems control systems Adaptive control Lyapunov method State feedback Programmable control Nonlinear control systems Nonlinear systems Uncertainty Parameter estimation

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Single Differential Modulation and Detection for MPSK in the Presence of Unknown Frequency Offset

Single Differential Modulation and Detection for MPSK in the...

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Asilomar Conference on Signals, systems & computers

作者： Jianhua Liu Petre Stoica Marvin Simon Jian Li Department of Electrical and Systems Engineering Embrey-Riddle Aeronautical University Daytona Beach FL USA Department of Systems and Control University of Uppsala Uppsala Sweden Jet Propulsion Laboratory Pasadena CA USA Department of Electrical and Computer Engineering University of Florida Gainesville FL USA

We consider improving the performance of communications over unknown channels with unknown frequency offsets. In lieu of the commonly suggested double differential (DD) modulation/detection, we consider single differential (SD) modulation/detection. We propose an approach that first estimates and compensates for the frequency offset and then detects using an existing multiple symbol detector for SD modulation. We introduce a simple data-symbol-independent frequency offset estimation method, which is reasonably accurate when using a data block larger than the one used for detection. Simulation results show that the SD modulation/detection approach proposed herein can significantly outperform the DD modulation/detection schemes.

关键词： Frequency estimation Detectors Maximum likelihood detection Costs Degradation systems engineering and theory Communication system control control systems Propulsion Laboratories

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