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IEEE Globecom Workshops

作者： Jing Jiang S. Thompson John M. Grant Peter Institute for Digital Communications University of Edinburgh Edinburgh UK Institute for Digital Communications Joint Research Institute for Signal & Image Processing School of Engineering University of Edinburgh Edinburgh EH9 3JL UK

A cooperative virtual-MIMO system that implements bit-interleaved coded modulation (BICM) transmission and compress-and-forward (CF) cooperation is presented in this paper. The key tasks of the relay include constructing a good codebook, and forwarding a compressed version of the received signals to the destination. Codebook designs of the Voronoi vector quantization (VQ) and the tree-structure vector quantization (TSVQ) to enable CF cooperation are described in this paper. A comparison in terms of the codebook design complexity and encoding complexity is presented. It is shown that the TSVQ is much simpler to design and operate and can achieve performance comparable to the optimal but more complicated Voronoi VQ. Error performance results show that the helping relay enables the proposed cooperative virtual-MIMO system to achieve close to MIMO performance.

关键词： Relays Encoding MIMO Complexity theory Receivers Quantization Transmitters

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Evaluating the Response Time of Large Scale Content Adaptation Systems Using Performance Evaluation Process Algebra

Evaluating the Response Time of Large Scale Content Adaptati...

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IEEE International Conference on Communications (ICC)

作者： J. Ding J. Hillston D. I. Laurenson The University of Edinburgh Edinburgh Edinburgh GB Laboratory of Foundations of Computer Science School of Informatics University of Edinburgh Edinburgh UK Institute of Digital Communications Joint Research Institute of Signal & Image Processing School of Engineering University of Edinburgh Edinburgh UK

With the increasing diversity of content as well as user preferences, and the heterogeneity of devices and network technologies, content adaptation has been widely acknowledged as an effective strategy to deliver services and content to users in a variety of contexts. This paper presents an evaluation of the response time of large scale content adaptation systems being developed under the auspices of the Mobile VCE, using the high-level modelling formalism -performance evaluation process algebra (PEPA). The relevant factors of the system performance, including the operation speed of individual entities, loading and resource conditions of the system, are determined and analysed.

关键词： Delay Large-scale systems Algebra Mobile communication Informatics Context-aware services Performance analysis Velocity measurement Time measurement Communications Society

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Improved in vivo fluorescence tomography and quantitation in small animals using a novel multiview, multispectral imaging system

Improved in vivo fluorescence tomography and quantitation in...

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Biomedical Optics, BIOMED 2010

作者： Gardner, Craig Dutta, Joyita Mitchell, Gregory S. Ahn, Sangtae Li, Changqing Harvey, Peter Gershman, Russel Sheedy, Stephen Mansfield, James R. Cherry, Simon R. Leahy, Richard M. Levenson, Richard M. Cambridge Research and Instrumentation Inc. Woburn MA United States Signal and Image Processing Institute Dept. of Electrical Engineering-Systems USC Los Angeles CA United States Dept. of Biomedical Engineering UC-Davis Davis CA United States

We report on the design and initial experimental results of a multiview, multispectral preclinical fluorescence tomography instrument, designed to improve quantitation of fluorescence molecular imaging in disease rese... 详细信息

ISBN: (纸本)9781557528872

关键词： Molecular imaging

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Upper Bounds for the Analysis of Trellis Coded Spatial Modulation over Correlated Fading Channels

Upper Bounds for the Analysis of Trellis Coded Spatial Modul...

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IEEE Conference on Vehicular Technology (VTC)

作者： Marco Di Renzo Raed Y. Mesleh Harald Haas Peter M. Grant Laboratory of Signals and Systems (LSS) Ecole Superieure d'Electricite (SUPELEC) French National Center for Scientific Research (CNRS) Gif-sur-Yvette France School of Engineering and Science Jacobs University Bremen Bremen Germany Institute of Digital Communications (IDCOM) Joint Research Institute of Signal and Image Processing University of Edinburgh Edinburgh UK

Trellis Coded Spatial Modulation (TCSM) is a novel transmission technology for Multiple-Input-Multiple-Output (MIMO) systems, which has been recently proposed to improve the performance of Spatial Modulation (SM) over correlated fading channels. The fundamental principle of TCSM is to use convolutional encoding and Maximum-Likelihood Sequence Estimation (MLSE) decoding to increase the free distance between sequences of spatial constellation points, thus improving, especially over spatially correlated fading channels, the end-to-end system performance. In this paper, we propose tight analytical bounds for performance analysis of TCSM over correlated fading channels. In particular, the contributions of this paper are as follows: i) we propose two asymptotically tight (for high signal-to-Noise-Ratios, SNRs) upper bounds for the analysis of uncoded SM schemes, which offer a better accuracy than already existing frameworks, ii) we propose a simple Chernoff bound for performance analysis of TCSM, which, although weak, can well capture the diversity order of the system, and iii) we propose an asymptotically tight (for high SNRs) true union bound for the accurate performance prediction of TCSM over correlated fading channels. Analytical frameworks and findings will also be substantiated via Monte Carlo simulations.

关键词： Upper bound Modulation coding Fading Performance analysis MIMO Samarium Maximum likelihood estimation Convolutional codes Convolution Maximum likelihood decoding

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Robust multi-object sensor fusion with unknown correlations

Robust multi-object sensor fusion with unknown correlations

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Sensor signal processing for Defence (SSPD 2010)

作者： Daniel Clark Simon Julier Ronald Mahler Branko Ristić Joint Research Institute in Signal and Image Processing Heriot-Watt University Riccarton Edinburgh UK University College London London UK Lockheed Martin Naval Electronics & Surveillance Systems-Eagan Eagan MN USA ISR Division DSTO Australia Edinburgh SA Australia

Distribution and decentralisation of fusion operations are key to network centric operations (NCOs) and distributed data fusion algorithms (DDF) have been developed to support them. These algorithms fuse data collected locally with state estimates propagated from other nodes. If the full advantages of NCOs are to be realised, these algorithms should exploit local information only: no single node, for example, should be an oracle which must maintain the entire state of the network. Uhlmann argued that many of these could be overcome if suboptimal solutions were used and proposed a principled suboptimal algorithm known as Covariance Intersection (CI). CI has proved to be a very powerful and general method for fusing data in arbitrary networks and has been used in a range of distributed and other applications where full correlation structures cannot be maintained. However, CI only utilizes the mean and covariance of the estimates and cannot exploit any additional distribution information such as the number of modes. The generalisation of CI to general probability distributions was first proposed by Mahler and independently derived by Hurley. We investigate the generalisation Covariance Intersection for multi-object posteriors by considering specific forms of multi-object posterior and their first-order moment densities, Probability Hypothesis Densities, as a prerequisite study for determining tractable implementations.

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Monte Carlo realisation of a distributed multi-object fusion algorithm

Monte Carlo realisation of a distributed multi-object fusion...

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Sensor signal processing for Defence (SSPD 2010)

作者： Murat Üney Simon Julier Daniel Clark Branko Ristić Department of Electrical Electronic & Computer Engineering School of Engineering & Physical Sciences Heriot-Watt University Edinburgh UK University College London London UK Joint Research Institute in Signal and Image Processing Heriot-Watt University Edinburgh UK ISR Division DSTO Australia Edinburgh SA Australia

We consider the problem of distributed target tracking in a multi-object, multi-sensor scenario in which the structure of the joint distribution of the estimate between different nodes is unknown. In this paper we present a preliminary implementation of Generalised Covariance Intersection (GCI) fusion rule for multi-object posteriors through a Monte Carlo realisation. We discuss the subtleties in the case of multi-object distributions and derive a scheme for sampling from Exponential Mixture Densities which are at the heart of the GCI. We demonstrate the improvement in localisation of multiple targets in a simulation scenario.

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Parallel Markov chain Monte Carlo computation for varying-dimension signal analysis

Parallel Markov chain Monte Carlo computation for varying-di...

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17th European signal processing Conference, EUSIPCO 2009

作者： Ye, Jing Wallace, Andrew Thompson, John Edinburgh Joint Research Institute in Signal and Image Processing Heriot-Watt University United Kingdom Edinburgh Joint Research Institute in Signal and Image Processing University of Edinburgh United Kingdom

Parallel implementation of Markov Chain Monte Carlo (MCMC) algorithms for Bayesian inference has been effective but is usually restricted to the case where the dimension of the parameter vector is fixed. We propose an efficient parallel solution for the varying-dimension problem by constructing multiple within-model MCMC chains and then combining the separate results to analyze the posterior distribution of dimensionality. We aim for parallel speed-up by reducing the length of the burn-in period and the individual chains in comparison with a serial, reversible jump MCMC (RJMCMC) algorithm. The parallel methodology is illustrated with application to a benchmarking, change point problem. © EURASIP, 2009.

关键词： Chains

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On capacity of cognitive radio networks with average interference power constraints

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IEEE Transactions on Wireless Communications 2009年第4期8卷 1620-1625页

作者： Wang, Cheng-Xiang Hong, Xuemin Chen, Hsiao-Hwa Thompson, John Joint Research Institute for Signal and Image Processing School of Engineering and Physical Sciences Heriot-Watt University United Kingdom Department of Electrical and Computer Engineering University of Waterloo ON Canada Department of Engineering Science National Cheng Kung University Taiwan Joint Research Institute for Signal and Image Processing Institute for Digital Communications University of Edinburgh United Kingdom

Cognitive radio (CR) has been considered as a promising technology to improve the spectrum utilization. In this paper we analyze the capacity of a CR network with average received interference power constraints. Under the assumptions of uniform node placements and a simple power control scheme, the maximum transmit power of a target CR transmitter is characterized by its cumulative distribution function (CDF). We study two CR scenarios for future applications. The first scenario is called the CR based central access network, which aims at providing broadband access to CR devices. In the second scenario, the so-called CR assisted virtual multiple-input multiple-output (MIMO) network, CR is used to improve the access capability of a cellular system. The uplink ergodic channel capacities of both scenarios are derived and analyzed with an emphasis on understanding the impact of numbers of primary users and CR users on the capacity. Numerical and simulation results suggest that the CR based central access network is more suitable for less-populated rural areas where a relatively low density of primary receivers is expected;while the CR assisted virtual MIMO network performs better in urban environments with a dense population of mobile CR users. © 2006 IEEE.

关键词： Cognitive radio

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Detecting low-resolution faces in video

Detecting low-resolution faces in video

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Intelligent Robots and Computer Vision XXVI: Algorithms and Techniques

作者： Robertson, Neil Janssen, Nils Joint Research Institute for Signal and Image Processing Heriot-Watt University Edinburgh United Kingdom

This paper presents a method for the detection of faces (via skin regions) in images where faces may be low-resolution and no assumptions are made about fine facial features being visible. This type of data is challenging because changes in appearance of skin regions occur due to changes in both lighting and resolution. We present a non-parametric classification scheme based on a histogram similarity measure. By comparing performance of commonly-used colour-spaces we find that the YIQ colour space with 16 histogram bins (in both 1 and 2 dimensions) gives the most accurate performance over a wide range of imaging conditions for non-parametric skin classification. We demonstrate better performance of the non-parametric approach vs. colour thresholding and a Gaussian classifier. Face detection is subsequently achieved via a simple aspect-ratio and we show results from indoor and outdoor scenes. © 2009 SPIE-IS&T.

关键词： Face recognition

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Probability of error for BPSK modulation in distributed beamforming with phase errors

Probability of error for BPSK modulation in distributed beam...

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International ITG Workshop on Smart Antennas, WSA 2009

作者： Song, Shuo Thompson, John S. Chung, Pei-Jung Grant, Peter M. Institute for Digital Communications Joint Research Institute for Signal and Image Processing School of Engineering and Electronics University of Edinburgh United Kingdom

This paper presents an investigation into the error probability performance for binary phase-shift keying modulation in distributed beamforming with phase errors. The effects of the number of nodes on the beamforming performance are examined as well as the influences of the cumulative phase errors and the total transmit power. Simulation results show a good match with the mathematical analysis of error probability in both static and time-varying channels.

关键词： Beamforming

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