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11th Annual International Symposium on Algorithms and Computation, ISAAC 2000

作者： Kubo, Norihiro Muramoto, Katsuhiro Shimozono, Shinichi School of Computer Science and Systems Enginieering Kyushu Inst. of Tech Iizuka820-8502 Japan FAD Iwashita Engineering Inc Nakahara Shinmachi 2-3 Tobata-ku Kitakyushu804-0003 Japan Dept. of Artificial Intelligence Kyushu Inst. of Tech Iizuka820-8502 Japan

ISBN: (纸本)3540412557

We present a quite simple, fast and practical algorithm to find a short cyclic tour that visits a set of points distributed on the plane. The algorithm runs in O(n log n) time with O(n) space, and is simple enough to easily implement on resource restricted machines. It constructs a tour essentially by axis-sorts of the points and takes a kind of the ‘fixed dissection strategy,’ though it neither tries to find best tours in subregions nor optimizes the order among subregions. As well as the worst-case approximation ratio of produced tours, we show that the algorithm is a ‘probabilistic’ constant-ratio approximation algorithm for uniform random distributions. We made computational comparisons of our algorithm, Karp’s partitioning algorithm, Lin-Kernighan local search, Arora’s randomized PTAS, etc. The results indicate that in running time our algorithm overwhelms existing ones, and the average approximation ratio is better or competitive. © Springer-Verlag Berlin Heidelberg 2000.

关键词： Approximation algorithms

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Stripe-based SPHIT lossy compression of volumetric medical images for low memory usage and uniform reconstruction quality

Stripe-based SPHIT lossy compression of volumetric medical i...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Y. Kim W.A. Pearlman Dept. of Electr. Comput. & Syst. Eng. Rensselaer Polytech. Inst. Troy NY USA Computer and Systems Engineering Department Rensselaer Polytechnic Institute RPI Troy NY USA

This paper presents a low memory implementation of efficient lossy volumetric medical image compression using the set partitioning in hierarchical trees (SPIHT) algorithm. The coding units in this three-dimensional wavelet transform and compression method are short sequences of horizontal stripes cut from the sequence of slices in the volumetric image. As the compression degree increases, the boundaries between adjacent coding units became increasingly visible. Unlike video, where image frames are viewed under dynamic conditions, the volume image is examined under static conditions and must not exhibit such boundary artifacts. In order to eliminate them, we utilize overlapping and averaging both at the intra-slice and inter-slice boundaries between adjacent and successive stripe sequences. Our low memory implementation smooths out considerably the variation in mean squared error among different slices and suffers only an insignificant loss in performance from that of a full memory implementation.

关键词： Image coding Biomedical imaging Image reconstruction Wavelet transforms Medical diagnostic imaging Image generation Hospitals Material storage Image segmentation Kilns

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TCP performance over heterogeneous networks

TCP performance over heterogeneous networks

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Conference on Local computer Networks (LCN)

作者： M. Arpaci H. Uzunalioglu J.A. Copel Sch. of Electr. & Comput. Eng. Georgia Inst. of Technol. Atlanta GA USA Communications Systems Center School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

In future IP networks, nodes supporting new congestion avoidance mechanisms like RED and ECN are going to exist together with nodes carrying traditional drop tail buffers. We study the performance of a set of TCP flows passing through two congested nodes in such a heterogeneous network. Our results show that unequal hop behaviour (in the form of RED and drop tail) in the congestion points can increase the bias against.TCP flows passing through multiple congested nodes. Parameter settings of RED become critical again in the dual-bottleneck situation just like in the single-bottleneck case. Furthermore, appropriate settings for single- and dual-bottleneck situations appear to be significantly different, making it more problematic for RED to provide a "better-than-drop tail" performance with a fixed set of parameters.

关键词： TCPIP IP networks Tail computer networks Web and internet services Degradation Throughput Delay H infinity control Protocols

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Vehicle cabin air quality monitor using gas sensors for improved safety

Vehicle cabin air quality monitor using gas sensors for impr...

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Conference on Optoelectronic and Microelectronic Materials and Devices

作者： K. Galatsis W. Wlodarski Y.X. Li K. Kalantar-zadeh Sensor Technology Laboratory School of Electrical and Computer Systems Engineering RMIT University Melbourne Australia RMIT University Melbourne VIC AU Sensor Technol. Lab. R. Melbourne Inst. of Technol. Vic. Australia

ISBN: (纸本)0780366980

A vehicle cabin air quality monitor using carbon monoxide (CO) and oxygen (O/sub 2/) gas sensors has been designed, developed and on-road tested. The continuous monitoring of oxygen and carbon monoxide provides added vehicle safety as alarms could be set off when dangerous gas concentrations are reached, preventing driver fatigue, drowsiness, and exhaust gas suicides. CO concentrations of 30 ppm and oxygen levels lower than 19.5% were experienced whilst driving.

关键词： Vehicle safety Gas detectors Air safety Vehicles Carbon dioxide computerized monitoring Australia Automobiles Electrical safety Sensor systems

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A joint source-channel coding approach to network transport on digital video

A joint source-channel coding approach to network transport ...

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

作者： B. Kurceren J.W. Modestino Dept. of Electr. Comput. & Syst. Eng. Rensselaer Polytech. Inst. Troy NY USA Electrical Computer and Systems Engineering Department Center for Image Processing Research Rensselaer Polytechnic Institute Troy NY USA

The use of forward error-control (FEC) coding, possibly in conjunction with passive-error recovery techniques, has emerged as a promising approach for real-time video transport over ATM networks for cell loss recovery and/or bit error correction, such as might be required for wireless links. Although FEC provides cell-loss recovery, through its erasure correcting capabilities, it also introduces transmission overhead which can possibly cause additional cell losses. A joint source-channel coding methodology is described to maximize the number of video sources multiplexed at a given quality of service (QoS), measured in terms of overall reproduced video quality. The transport channel is modeled as a block interference channel (BIC) and the multiplexer as a single server, deterministic service, finite buffer supporting N users. Based upon an information-theoretic characterization of the BIC and large deviation bounds on the buffer overflow probability, we describe a methodology that provides theoretically achievable upper limits on the number of sources multiplexed at a given level of performance. Performance of a specific coding technique using an MPEG-2 source encoder and interlaced non-binary Reed-Solomon (RS) channel codes is illustrated and shown to approach the information-theoretic predictions with increasing levels of complexity.

关键词： Forward error correction Quality of service Error correction Asynchronous transfer mode Error correction codes Propagation losses Interference channels Multiplexing Buffer overflow Reed-Solomon codes

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Application of a genetic algorithm in triangulation of a 3-D object surface

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International Journal of computers and Applications 2000年第2期22卷 73-77页

作者： Zhenyu, Chen Mbede, J.B. Yan, Zhou Dehua, Li Hanping, Hu State Commn. Res. Open Lab. Image P. Inst. Pattern Recog. Artif. Intell. Huazhong Univ. of Sci. and Technol. 430074 Wuhan China Intelligent Contr. and Robotics Lab. Dept. of Contr. Sci. and Engineering Huazhong Univ. of Sci. and Technol. 430074 Wuhan China Second Artillery Institute Huazhong Univ. of Sci. and Technol. Inst. Pattern Recog. Artif. Intell. Huazhong Univ. of Sci. and Technol. Second Artillery Institute China Wuhan University China Artificial Intelligence Department University of Edinburgh Inst. of AI and Pattern Recognition Huazhong Univ. of Sci. and Technol. China Cogn. Sci. Natl. Key Found. Res. P. Douala University Cameroon Tübingen University Germany Automatic Control Laboratory Darmstadt University Department of Service Cameroon Min. of National Education Robotics Laboratory Huazhong Univ. of Sci. and Technol. Wuhan China Assoc. Connectionnistes These-ACTH Rennes France IEEE Soc. of Robotics and Automation IEEE Society of Control Systems IASTED Assoc. Jeunes Chercheurs Robotique France Navy University of Engineering China Huazhong Univ. of Sci. and Technol. China Department of Computer Science Airforce Radar Acad. of Engineering China Inst. of P.R and AI Huazhong Univ. of Sci. and Technol.

This paper proposes a genetic-based algorithm for surface reconstruction of three-dimension (3-D) objects from a group of contours representing its section plane lines. The algorithm can optimize the triangulation of the surface of 3-D objects with a multi-objective optimization function to meet the needs of a wide range of applications. Further, a new crossover operator for triangulation and a new 3-D quadrilateral mutation operator are also introduced.

关键词： Object recognition

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Tunable red vertical cavity surface emitting lasers using electrostatic actuation

Tunable red vertical cavity surface emitting lasers using el...

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Conference on Optoelectronic and Microelectronic Materials and Devices

作者： J.A. Lott E.M. Ochoa W.J. Siskaninetz M.J. Noble Computer Electrical Engineering Electrical Engineering of Institute Technology OH USA Dept. of Electr. & Comput. Eng. Air Force Inst. of Technol. Wright-Patterson AFB OH USA Air Force Research Laboratory OH USA Air Force Electronic Systems Center MA USA

We report a tunable red vertical cavity surface emitting laser (VCSEL) with a flexible micro-electro-mechanical (MEM) top distributed Bragg reflector. The peak emission wavelength is electrically tunable over a range ... 详细信息

ISBN: (纸本)0780366980

关键词： Vertical cavity surface emitting lasers Tunable circuits and devices Surface emitting lasers Electrostatic actuators Distributed Bragg reflectors Optical surface waves Laser tuning Threshold current RNA Gallium arsenide

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Electromagnetic limits of planar integrated resonant/transformer structures for power electronic applications

Electromagnetic limits of planar integrated resonant/transfo...

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IEEE International Workshop on Integrated Power Packaging

作者： J.T. Strydom J.D. Van Wyk J.A. Ferreira Bradley Dept. of Electr. & Comput. Eng. Virginia Polytech. Inst. & State Univ. Blacksburg VA USA NSF ERC for Power Electronics Systems The Bradley Department of Electricaland Computer Engineering Virginia Polytechnic and State University Blacksburg VA USA

ISBN: (纸本)0780364376

The integrated planar resonant/transformer structure analysed is constructed from planar ferrites, conductive layers, leakage layers and slabs of ceramic dielectric. The electromagnetic limits are analysed in terms of the permeabilities, permittivities and conductivities, skin effect, breakdown field and physical dimensions. An example of a converter with an integrated resonant/transformer (LLCT) structure is used to illustrate the analysis. This analysis indicates that the electromagnetic limits results in volumes two orders of magnitude smaller than at present, illustrating that the power density is currently only limited by construction technology. The thermal limit is expected to be the next barrier within one order of magnitude.

关键词： Resonance Electromagnetic analysis Ferrites Slabs Ceramics Dielectrics Electromagnetic fields Permeability Permittivity Conductivity

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Study of a Cr doped TiO/sub 2/ derived from sol-gel process for gas sensing

Study of a Cr doped TiO/sub 2/ derived from sol-gel process ...

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Conference on Optoelectronic and Microelectronic Materials and Devices

作者： J.M. Booth L. Nguyen C.J. Rix D.E. Mainwaring Y.X. Li W. Wlodarski S.H. Moslih S.P. Russo School of Electrical & Computer Systems Engineering RMIT University Melbourne Australia Departments of Appl. Chem. R. Melbourne Inst. of Technol. Vic. Australia Applied Physics RMIT University Melbourne Australia Department of Applied Chemistry RMIT University Melbourne Australia

ISBN: (纸本)0780366980

The sol-gel route to thin bimetallic oxide sensor films was studied in terms of the evolution of a viscoelastic Ti gel precursor containing occluded Cr. The influence of Cr:Ti atomic ratio and annealing temperature was related to the resultant microstructure, morphology and oxygen sensing response of the annealed thin films. It was shown that progressive increase in Cr content changed the Ti-O properties from a n-type to a p-type semiconductor film with a commensurate reversal in sensor response.

关键词： Chromium Temperature sensors Thin film sensors Annealing Viscosity Elasticity Microstructure Morphology Semiconductor thin films Semiconductor films

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Survey of computational complexity results in systems and control

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Automatica 2000年第9期36卷 1249-1274页

作者： Blondel, Vincent D. Tsitsiklis, John N. Dept. of Mathematical Engineering Ctr. Syst. Eng. Appl. and Mechanics University of Louvain B-1348 Louvain-la-Neuve Belgium Lab. for Info. and Decision Systems Massachusetts Inst. of Technology Cambridge MA 02139 United States Massachusetts Inst. of Technology Cambridge MA United States Department of Electrical Engineering Stanford University Stanford CA United States Dept. of EECS University of California Berkeley CA United States Institute for Computer Science Iraklion Greece University of Louvain Louvain-la-Neuve Belgium Fr. Natl. Res. Ctr. Contr. Comp. S. INRIA Paris France Ecole Normale Supérieure Lyon France

The purpose of this paper is twofold: (a) to provide a tutorial introduction to some key concepts from the theory of computational complexity, highlighting their relevance to systems and control theory, and (b) to survey the relatively recent research activity lying at the interface between these fields. We begin with a brief introduction to models of computation, the concepts of undecidability, polynomial-time algorithms, NP-completeness, and the implications of intractability results. We then survey a number of problems that arise in systems and control theory, some of them classical, some of them related to current research. We discuss them from the point of view of computational complexity and also point out many open problems. In particular, we consider problems related to stability or stabilizability of linear systems with parametric uncertainty, robust control, time-varying linear systems, nonlinear and hybrid systems, and stochastic optimal control.

关键词： Computational complexity

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