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A distributed and adaptive signal processing approach to exploiting correlation in sensor networks

Ad Hoc Networks 2004年第4期2卷 387-403页

作者： Chou, Jim Petrovic, Dragan Ramchandran, Kannan Department of EECS University of California at Berkeley Berkeley CA 94709 United States

We propose a novel approach to reducing energy consumption in sensor networks using a distributed adaptive signal processing framework and efficient algorithm. This work was supported in part by DARPA-F30602-00-2-0538, NSF-CCR-0219722 and Intel.1 While the topic of energy-aware routing to alleviate energy consumption in sensor networks has received attention recently [C. Toh, IEEE Commun. Mag. June (2001) 138;R. Shah, J. Rabaey, Proc. IEEE WCNC, March 2002], in this paper, we propose an orthogonal approach to complement previous methods. Specifically, we propose a distributed way of continuously exploiting existing correlations in sensor data based on adaptive signal processing and distributed source coding principles. Our approach enables sensor nodes to blindly compress their readings with respect to one another without the need for explicit and energy-expensive inter-sensor communication to effect this compression. Furthermore, the distributed algorithm used by each sensor node is extremely low in complexity and easy to implement (i.e., one modulo operation), while an adaptive filtering framework is used at the data gathering unit to continuously learn the relevant correlation structures in the sensor data. Applying the algorithm to testbed data resulted in energy savings of 10-65% for a multitude of sensor modalities. © 2003 Publishesd by Elsevier B.V.

关键词： Signal processing

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Video coding with H.264/AVC: Tools, performance, and complexity

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IEEE Circuits and Systems Magazine 2004年第1期4卷 7-28页

作者： Ostermann, Jörn Bormans, Jan List, Peter Marpe, Detlev Narroschke, Matthias Pereira, Fernando Stockhammer, Thomas Wedi, Thomas Inst. Theor. Nachrichtentech./I. University of Hannover Hannover Germany IMEC Leuven Belgium Deutsche Telecom T-Systems Darmstadt Germany Fraunhofer-Inst. for Telecom. Heinrich Hertz Institute Berlin Germany Inst. Theor. Nachrichtentech./I. University of Hannover Appelstr. 9a 30167 Hannover Germany Instituto Superior Técnico Inst. de Telecom. Lisbaa Portugal Inst. for Communications Engineering Munich University of Technology Germany

H.264/AVC, the result of the collaboration between the ISO/IEC Moving Picture Experts Group and the ITU-T Video Coding Experts Group, is the latest standard for video coding. The goals of this standardization effort were enhanced compression efficiency, network friendly video representation for interactive (video telephony) and non-interactive applications (broadcast, streaming, storage, video on demand). H.264/AVC provides gains in compression efficiency of up to 50% over a wide range of bit rates and video resolutions compared to previous standards. Compared to previous standards, the decoder complexity is about four times that of MPEG-2 and two times that of MPEG-4 visual Simple Profile. This paper provides an overview of the new tools, features and complexity of H.264/AVC.

关键词： image coding

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Sequential RBF function estimator: memory regression network

Sequential RBF function estimator: memory regression network

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IEEE International Conference on Systems, Man and Cybernetics

作者： Chi-kin Chow Hung-tat Tsui Visual Signal Processing and Communications Laboratory Departmenl of Electronic Engineering Chinese University of Hong Kong Hong Kong China

The neural-network training algorithm can be divided into 2 categories: (1) batch mode and (2) sequential mode. In this paper, a novel online RBF network called "memory regression network (MRN)" is proposed. Different from the previous approaches (de Freitas, N, et al., Aug. 1999), (Schiffman, W, et al., 1993), MRN involves two types of memories: experience and neuron, which handle short and long term memories respectively. By simulating human's learning behavior, a given function can be estimated without memorizing the whole training set. Two sets of function estimation experiments are examined in order to illustrate the performance of the proposed algorithm. The results show that MRN can effectively approximate the given function within a reasonable time and acceptable mean square error

关键词： Neurons Neural networks Signal processing algorithms Radial basis function networks Radio access networks Robots Laboratories Humans Interpolation image processing

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Dual-mode image quality assessment metric

Dual-mode image quality assessment metric

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IEEE Region 8 International Symposium on Video/image processing and Multimedia communications (EURASIP)

作者： F.Z.C. Chin C.S. Xydeas Department of Communication Systems Lancaster University Lancaster UK

This paper presents a perceptual image quality assessment metric based on the visible differences predictor (VDP) (Daly, 1993). The proposed metric operates in two modes. In quality mode, the metric produces a single value representation of the overall visible image quality (VIQ), whereas in distortion mode, the metric provides four distortion values each associated with a specific type of image content. The correlation coefficient between the objective VIQ and subjective test results is 0.96, compared to 0.86 obtained by the PSNR measure.

关键词： image quality image edge detection Nonlinear distortion PSNR Distortion measurement Humans Pixel Testing visual system Frequency

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Network security in video communications using chaotic systems

Network security in video communications using chaotic syste...

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visual communications and image processing 2000

作者： Memon, Qurban A. Ali, Zahid Hamdard Univ Karachi Pakistan

In this paper, we report implementation of encryption of the signal in networked environment using synchronized chaos. The science of chaos has successfully been explored and implemented in hardware for communication signals by Cuomo et all in 1993, although he (author himself) claimed that the mathematics behind the phenomenon was still obscure and not very clear. We are utilizing this unpredictable, random phenomenon called chaos to code our information by superimposing it on a chaotic signal. We applied this technique to different formats of data and results were 100% in the sense that decoded files were run without error. This testing scenario encourages use of chaos in information coding across networks. It is shown that, in this environment, the security breach may not be possible even if sender and receiver have compatible scramblers and descramblers, and the key is also known to the receiver.

关键词： image communication systems

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visual communications and image processing 1993

Visual Communications and Image Processing 1993

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visual communications and image processing 1993

The proceedings contain 162 papers. The topics discussed include: facial image tracking system architecture utilizing real-time labeling;subjective mode regions of picture and painting of 3-D picture;model based segmentation of the tongue surface using a modified scale space filter;extraction of two-dimensional arbitrary shapes using a genetic algorithm;symmetrical segmentation-based image coding;a parallel approach to character recognition and its VLSI implementation;time-varying homotopy and the animation of facial expressions for 3D virtual space teleconferencing;very low bit-rate video coding with object-based motion compensation and orthogonal transform;fractal approach to low rate video coding;localized fractal dimension measurement in digital mammographic images;sequence coding based on the fractal theory of iterated tranformations systems;and joint multigrid estimation of 2D motion and object boundaries using boundary patterns.

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ANALYZING PULMONARY CAPILLARY-PRESSURE - MORE ACCURATE MEASUREMENTS USING MUTUAL WAVELET PACKETS FOR ADAPTIVE FILTERING

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IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE 1995年第2期14卷 179-185页

作者： KARRAKCHOU, M LAMBRECHT, CV KUNT, M Signal Processing Laboratory Swiss Federal Institute of Technology Switzerland

A new mutual wavelet packets scheme is proposed for subband adaptive filtering. Its relation to the existing literature on the subject is outlined. The proposed scheme performs a decomposition of the two signals used in the adaptation process onto the same optimal basis. That basis is chosen so that it favors the adaptation performance. A new criterion, based on a functional of the two signals, is introduced. This proposed criterion consists in the maximization of the magnitude of the cross-correlation samples of the two signals considered. This maximizes the cross-correlation vector of the well known normal equations. At the expense of a slightly higher computational complexity, the mutual wavelet packets scheme reduces the aliasing drawback of regular subband adaptive filtering, preserving its main advantages. Simulations have been performed on pulmonary capillary pressure transients for respiratory interference cancelling. The method proved to be more efficient than classical methods.< >

关键词： Adaptive filters Arteries Lungs Finite impulse response filter Pressure measurement Catheters Filtering Interference cancellation IIR filters Convergence

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Perceptual embedded image coding using wavelet transforms

Perceptual embedded image coding using wavelet transforms

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IEEE International Conference on image processing

作者： A. Mazzarri R. Leonardi Signals and Communications Laboratory D.E.A D.E.A. University of Brescia Italy

We present a modified version of an embedded wavelet coding scheme, first suggested by Shapiro (see IEEE Transactions on Signal processing, vol.41, no. 12, p.3445-3462, 1993), that improves the performance of the original algorithm in a visual subjective distortion sense. We preserve the features of the original Shapiro's embedded coder. It is possible to choose a fixed target bit rate, as the information needed to represent an image coded at some rate always contains the needed information for the same image coded at lower rates. Therefore, the decoder can cease decoding the bit stream at any point, simulating an image coded at a lower rate corresponding to the truncated bit stream. We also introduce some perceptive improvements by adopting different (more regular) filters with respect to the original QMF pyramid filters proposed by Simoncelli, Hingorani et al. (1987) and used by Shapiro. These filters are synthesized using a "wavelet approach" instead of a "subband approach", and this leads to a better control on their regularity properties, jointly with better perceptual performance.

关键词： image coding Wavelet transforms Filters Discrete wavelet transforms Streaming media Quantization Wavelet packets Bit rate Decoding Entropy coding

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TERRAIN ADAPTIVE HUMAN WALKING ANIMATION

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SYSTEMS AND COMPUTERS IN JAPAN 1995年第5期26卷 79-88页

作者： TSUTSUGUCHI, K SAKAINO, H WATANABE, Y Member NTT Human Interface Laboratories Yokosuka Japan 238 Hidetorno Sakaino received his B.E. degree in 1986 and his M.E. degree in 1988 from Hokkaido Univ. Hokkaido Japan. He is a Research Engineer in NTT HI Labs. From 1988 to 1990 he worked as an engineer at the Visual Media Division in NYT HI Labs. In 1993 he began to work in the Advanced Video Processing Laboratory HI Labs NTT. His current research interests are representations of elastic objects and their transformations given the interaction between fluid dynamics and moving objects. Yashuhiko Watanabe received his Bachelor's degree from Niigata Univ. Niigata Japan in 1981. He is the Senior Research Engineer in the Advanced Video Processing Laboratory of NIT HI Labs. He is presently researching 3D volume processinghisualization systems. Since joining the Electrical Communications Laboratories NTT in 1981 he has been working on facsimile communication systems and Videotex communication systems. He is a member of the Institute of Image Electronic Engineers of Japan.

This paper describes a method for automatically generating human walking sequences that match the path set to the given terrain. The Environment Adaptive Human Walking Animation (EAW) module using this method offers to users an interface that can unite human walking motion with the environment in virtual worlds. The EAW module has a 4-layer structure comprising the GUI level, the control level, the motion generation level and the rendering level. The EAW module realizes the adaptation to the 3D terrain by using ''area divisions'' and ''step divisions'' for the walking path in the control level, and generates the walking motion sequences by using the ''E-KLAW'' method that uses dynamics and kinematics in the motion generation level. By using this module, the user's tasks are made significantly simpler and the user can incorporate human motion into various scenes.

关键词： COMPUTER ANIMATION ENVIRONMENT ADAPTIVE HUMAN WALKING EAW MODULE E-KLAW DYNAMICS KINEMATICS USER INTERFACE

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visual communications and image processing '92

Visual Communications and Image Processing '92

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visual communications and image processing '92

The Proceedings first volume contains 40 papers. The topics covered include hierarchical image coding, motion analysis, feature extraction, image restoration, video coding, morphological and related nonlinear filters.

ISBN: (纸本)0819410187

关键词： image processing

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