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作者： Wang, Baosheng Kuo, Andy Farahmand, Touraj Ivanov, André Cho, Yong B. Tabatabaei, Sassan SoC Laboratory University of British Columbia Canada Department of Electronics Engineering Konkuk University Seoul Korea Republic of Guide Technology Inc. Sunnyvale CA United States ATI Technologies Inc. Markham Ont. Canada Research Lab. Department of Electrical and Computer Engineering University of British Columbia Department of Electrical and Computer Engineering University of British Columbia IEEE Computer Society IEEE British Columbia Advanced Systems Institute Virage Logic Corporation

This paper extends the timing test model in [5] to be more realistic by including the effects of the test fixtures between a device under test and a tester. The paper enables analyzing the trade-offs that arise between the predicted yield and the required overall test environment timing accuracy (OTETA) which involves the tester overall timing accuracy (OTA) and the test fixtures' impacts. We specifically focus on the application of the extended model to predict the test yield of standard high-speed interconnects, such as PCI Express, Parallel/Serial RapidIO, and HyperTransport. The extended model reveals that achieving an actual yield of 80% with a test escape of 300 DPM (Defects Per Million) requires an equivalent OTETA that is about half the acceptable absolute limit of the tested parameter. © 2005 Springer Science + Business Media, Inc.

关键词： Scheduling

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Incremental discovery of object parts in video sequences

Incremental discovery of object parts in video sequences

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International Conference on computer Vision (ICCV)

作者： S. Drouin P. Hebert M. Parizeau Computer Vision and Systems Laboratory Department of Electrical and Computer Engineering Laval University Sainte-Foy QUE Canada

This paper addresses the fundamental problem of automatically discovering an unknown moving deformable object in a monocular video sequence. No prior model of the object is used; it is only assumed that the object is composed of a set of apparently rigid parts that are not necessarily visible simultaneously, making it possible to circumvent the typical constraint of model initialization. A set of rigid parts describing the object is incrementally extracted in a modeling-tracking loop with reinforced memory. In this framework, low-level segmentation is considered as a necessary but non reliable process that helps initiating hypotheses. Motion-based layer segmentation from feature points and edges is applied only when and where no modeled parts can be tracked. Using the quantity of motion measure, it is further shown how to deal with temporal scale. The interest for this approach in applications such as human tracking is demonstrated for a set of various sequences including a rapidly evolving shape

关键词： Video sequences Humans Tracking Shape computer vision Biological system modeling Image segmentation Motion analysis Laboratories Motion measurement

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Robust encryption for secure image transmission over wireless channels

Robust encryption for secure image transmission over wireles...

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IEEE International Conference on Communications (ICC)

作者： C. Nanjunda M.A. Haleem R. Chandramouli Multimedia System Networking and Communications (MSyNC) Laboratory Department of Electrical and Computer Engineering Stevens Institute of Technology Hoboken NJ USA

The security of multimedia data transmitted over wireless networks is of increased interest. Encryption mechanisms securely transmit multimedia data over insecure networks. A major issue that has received very little attention so far is that the very same properties that gives ciphers (encryption mechanisms) their cryptographic strength make them sensitive to channel errors as well. In addition, this would enhance the error propagation inherent in compressed data. Therefore provision of security for multimedia transmission over wireless channel results in throughput loss. Nevertheless this lost throughput is traded for increased security. To our knowledge there has been no substantial effort to optimize this tradeoff. Opportunistic encryption proposed in this work is a way to optimize the tradeoff between security offered and the throughput lost due to a cipher. We show that opportunistic encryption methods that adapt to channel variations will lead to an overall increase in the system performance. Two broad scenarios based on channel knowledge are considered, (a) exact channel state information up to a finite time horizon is known and (b) only the average signal-to-noise ratio (SNR) is known. Proposed opportunistic encryption framework is found to achieve significant gains in throughput compared to fixed block length encryption methods for a wide range of average SNR values. We have shown that applying opportunistic encryption on JPEG compressed image results in a better quality of received image and improved security compared to fixed block length encryption.

关键词： Robustness Cryptography Image communication Communication system security Throughput Data security Wireless networks Mechanical factors Wireless sensor networks Propagation losses

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"Wireless" control of spatially distributed power electronics

"Wireless" control of spatially distributed power electronic...

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Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC)

作者： S.K. Mazumder K. Acharya M. Tahir Laboratory of Energy and Switching Electrmics Systems Department of Electrical and Computer Engineering University of Illinois Chicago IL USA Laboratory of Energy and Switching Electmics Systems Department of Electrical and Computer Engineering University of Illinois Chicago IL USA

We propose a wireless control technique for spatially distributed power electronic systems and demonstrate its applicability for master-slave control of two parallel converters, namely a two-module parallel buck converter and a two-module parallel single-phase voltage source inverter. This scheme uses radiofrequency based communication to eliminate the need for multiple physical connections among the various modules of the parallel converters and is expected to lead to simpler and redundant design of distributed power systems that is achievable using the droop method, while maintaining load sharing among the various modules. The proposed method can also be used as a backup for wire-based control of parallel converters, in applications where fault tolerance is of critical importance

关键词： Distributed control Power electronics Communication system control Voltage control Control systems Master-slave Buck converters Inverters Radio frequency Power system faults

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On the advantages of multi-hop extensions to the IEEE 802.11 infrastructure mode

On the advantages of multi-hop extensions to the IEEE 802.11...

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IEEE Conference on Wireless Communications and networking

作者： S. Narayanan Pei Liu S.S. Panwar Panasonic Digital Networking Laboratory Princeton NJ USA The Department of Electrical and Computer Engineering Polytechnic University Brooklyn NY USA

IEEE 802.11 specifies two modes of operation, an infrastructure mode where nodes communicate to/through an access point, and an ad-hoc mode, where nodes communicate with each other directly. Neither mode supports multiple hop transmissions between these nodes. In this paper we present two advantages in extending 802.11 MAC to support multiple hops in the infrastructure mode. One advantage is higher available bandwidth in a multi-rate 802.11 network. IEEE 802.11 allows hosts to select different transmission rates based on the quality of the signal received by the host. Based on performance results both from analytical modeling and simulations, we demonstrate that the total available bandwidth can be improved by using multiple hops instead of reducing the transmission rates of nodes. We present the results in terms of both the increase in total throughput of the network and the available throughput for the forwarding node. The second advantage presented is that by using multi-hop transmissions, the power of transmission at the edges of 802.11 cells can be reduced resulting in lower interference with nodes at the edges of other 802.11 cells. This leads to a more uniform coverage, with increased throughput experienced by nodes at the cell edges.

关键词： Throughput Interference Bandwidth Analytical models Wireless LAN Laboratories Performance analysis Helium Spread spectrum communication Fading

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Simulation of a LV power distribution cable as communication medium - a finite element approach

Simulation of a LV power distribution cable as communication...

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Power Tech Conference

作者： G. T. Andreou D. P. Labridis Power Systems Laboratory of the Department of Electrical & Computer Engineering Aristotle University of Thessaloniki Thessaloniki Greece

Many models proposed in the literature to describe Low Voltage power distribution networks in consumer premises as communication media require knowledge of the electrical parameters of the cables comprising these networks. These parameters are nevertheless affected by a large number of factors which may vary greatly from case to case, making it thus very difficult to achieve an exact estimation about them. In this work a finite element approach is used for the simulation of a power distribution cable as communication medium, and the operational series impedance per unit length of a widely used cable type is derived. Moreover, the variation of the cable's operational series impedance versus current frequency, cable distance from earth and earth resistivity is presented.

关键词： Power distribution Power cables Communication cables Finite element methods Impedance Earth Low voltage Power systems Frequency Conductivity

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Equivalent resistivity approximation of two-layer earth structures for earth return impedance calculations

Equivalent resistivity approximation of two-layer earth stru...

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Power Tech Conference

作者： D. A. Tsiamitros G. K. Papagiannis P. S. Dokopoulos Department of Electrical & Computer Engineering Power Systems Laboratory Aristotle University of Thessaloniki Thessaloniki Greece

The equivalence conditions between homogeneous and two-layer earth structures are investigated in this paper. The analysis is based on the comparison between the two-layer and the homogeneous earth return impedance relations. The aim is the derivation of a new simple formula to connect the homogeneous earth equivalent resistivity with the two-layer earth electromagnetic and geometric properties. Thus, the relatively simple expressions for the impedance calculation of the homogeneous earth case can be used for two-layer earth models. The new formula is implemented for six actual cases of two-layer earth models. The two-layer earth impedances are calculated for various configurations, including overhead transmission lines, underground cable systems and a combination of overhead line and underground conductor. The calculated impedances are compared to the corresponding for the homogeneous earth, using the equivalent resistivity given by the new formula.

关键词： Earth Impedance Conductors Cables Permeability Power transmission lines Power system modeling Permittivity Conductivity measurement Soil

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Guest Editors' Introduction

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IEEE Transactions on computers 2005年第10期54卷 1185-1187页

作者： Wen-mei W. Hwu K.V. Palem Department of Electrical and Computer Engineering 256 Computer and Systems Research Laboratory University of Illinois Urbana-Champaign Urbana IL USA Center for Research on Embedded Systems and Technology School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

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Inference with minimal communication: a decision-theoretic variational approach 05

Inference with minimal communication: a decision-theoretic v...

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Proceedings of the 19th International Conference on Neural Information Processing systems

作者： O. Patrick Kreidl Alan S. Willsky Department of Electrical Engineering and Computer Science MIT Laboratory for Information and Decision Systems Cambridge MA

Given a directed graphical model with binary-valued hidden nodes and real-valued noisy observations, consider deciding upon the maximum a-posteriori (MAP) or the maximum posterior-marginal (MPM) assignment under the restriction that each node broadcasts only to its children exactly one single-bit message. We present a variational formulation, viewing the processing rules local to all nodes as degrees-of-freedom, that minimizes the loss in expected (MAP or MPM) performance subject to such online communication constraints. The approach leads to a novel message-passing algorithm to be executed offline, or before observations are realized, which mitigates the performance loss by iteratively coupling all rules in a manner implicitly driven by global statistics. We also provide (i) illustrative examples, (ii) assumptions that guarantee convergence and efficiency and (iii) connections to active research areas.

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Comet: a scalable coordination space for decentralized distributed environments

Comet: a scalable coordination space for decentralized distr...

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International Workshop on Hot Topics in Peer-to-Peer systems

作者： Zhen Li M. Parashar Applied Software Systems Laboratory Department of Electrical and Computer Engineering Rutgers University NJ USA

The scale, heterogeneity, and dynamism of emerging distributed and decentralized environments make coordination a significant and challenging problem. In this paper we present Comet, a scalable peer-to-peer content-based coordination space. Comet provides a global virtual shared-space that can be associatively accessed by all peer nodes in the system, and access is independent of the physical location of the tuples or identifiers of the host. Dynamically constructed, transient coordination spaces are also supported to enable context locality to be explicitly exploited for improving system performance. The design, implementation, and experimental evaluation of Comet using the PlanetLab platform are presented.

关键词： Peer to peer computing Distributed computing Context Software systems System performance Disaster management Runtime Management information systems Grid computing Pervasive computing

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