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Building conditions in Yau Tsim Mong, Hong Kong: Appraisal, exploration and estimation

Journal of Building Appraisal 2008年第4期3卷 319-329页

作者： Yau, Yung City University of Hong Kong Department of Public and Social Administration City University of Hong Kong Kowloon Tat Chee Avenue Hong Kong

Like many other developed cities, Hong Kong has been suffering from acute problems of urban decay. To solve this building crisis, knowledge of the condition profile of all buildings in Hong Kong is vital. A territory-wide evaluation of building conditions is required for providing valuable information to public organisations to prioritise action areas and facilitate resource allocation. Through such an exercise, the inherent problem of information asymmetry in building conditions can be resolved by means of screening or labelling. Buildings in better condition will be rewarded with a premium in property price, and this can foster a culture of building care through market forces. Assessing the performance of the whole stock of buildings in the city, however, can be a lengthy and costly process. In this light, this study proposed a practical but justifiable alternative for jump-starting the process. In the proposal, exogenous factors that could explain the variations in building conditions are explored using actual assessment information, and these determinants are used to estimate the conditions of other buildings without the need of actual assessments. The empirical findings show that this proposed estimation algorithm works and has a number of practical and policy implications. © 2008 PALGRAVE MACMILLAN LTD.

关键词： Building conditions estimation algorithm Hong Kong Urban regeneration

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Metrics of Algebraic Closures in Pattern Recognition Problems with Two Nonoverlapping Classes

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COMPUTATIONAL MATHEMATICS AND MATHEMATICAL PHYSICS 2008年第5期48卷 866-876页

作者： D'yakonov, A. G. Moscow MV Lomonosov State Univ Fac Computat Math & Cybernet Moscow 119992 Russia

It is shown that, in the pattern recognition problem with two nonoverlapping classes, the matrices of estimates of the object closeness are described by a metric. The transition to the algebraic closure of the model of recognizing operators of finite degree corresponds to the application of a special transformation of this metric. It is proved that the minimal degree correct algorithm can be found as a polynomial of a special form. A simple criterion for testing classification implementations is obtained.

关键词： pattern recognition estimation algorithm matrices of estimates correct algorithm algebra over algorithms metric Gram's matrix minimal degree

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Issues and challenges in performance assessment of multitarget tracking algorithms with applications to real-world problems: How useful are the theoretical bounds in the real-world?

Issues and challenges in performance assessment of multitarg...

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The International Society for Optical Engineering (SPIE)

作者： Kirubarajan, T. Estimation Tracking and Fusion Research Laboratory Electrical and Computer Engineering Department McMaster University Hamilton ON Canada

ISBN: (纸本)9780819471598

A number of performance bounds like, for example, Cramer-Rao Lower Bound and Weiss-Weinstein Bound, have been derived to quantify the performance achievable by any algorithm in state estimation problems. These bounds are evaluated at the ground truth, which means that the exact bound is available only for simulation-based or instrumented real experiments. Also, a number of assumptions on the statistics, state models and their evolution over time are made in order to facilitate the derivation of these complex bounds. As a result, these bounds are at best approximations of achievable performance. In addition, these bounds are often computationally cumbersome, if at all possible, to evaluate in realistic multisensor-multitarget tracking problems. In spite of these limitations, the bounds have been used successfully for performance prediction, tracker evaluation and sensor resource management. In this short paper, we briefly discuss the usefulness of theoretical bounds as realistic performance evaluation measures in real-world tracking problems.

关键词： Cramer-Rao lower bound estimation algorithm Multisensor-multitarget tracking Performance bounds Performance evaluation Weiss-Weinstein bound

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Algebra over estimation algorithms: Normalization and division

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Computational Mathematics and Mathematical Physics 2007年第6期47卷 1050-1060页

作者： D'yakonov A.G. Faculty of Computational Mathematics and Cybernetics Moscow State University Leninskie gory Moscow 119992 Russian Federation

An algebra over recognition algorithms supplemented with a normalization operation (under various definitions) and the division operation is investigated. Correctness criteria for various algebraic closures are obtain... 详细信息

关键词： Algebra over algorithms Correct algorithm Division of algorithms estimation algorithm Matrices of estimates Normalization Pattern recognition

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A multigroup priority queueing MAC protocol for wireless networks with multipacket reception

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2008年第unknown期2008卷 970842-970842页

作者： Yang, Wen-Fang Wu, Jwo-Yuh Wang, Li-Chun Lee, Ta-Sung Natl Chiao Tung Univ Dept Commun Engn Hsinchu Taiwan

Relying on a simple flag-assisted mechanism, a multigroup priority queueing (MGPQ) medium access control (MAC) protocol is proposed for the wireless networks with multipacket reception ( MPR). The proposed MGPQ scheme is capable of overcoming two major performance bottlenecks inherent in the existing MPR MAC protocols. First, the proposed solution can automatically produce the list of active users by observing the network traffic conditions, remove the need of active user estimation algorithm, and thus can largely reduce the algorithm complexity. Second, the packet blocking constraint imposed on the active users for keeping compliant with prediction is relaxed. As a result, the proposed MGPQ is not only applicable to both homogeneous and heterogeneous cases, but also outperforms the existing MPRMAC protocols. Simulation results show that the network throughput can be improved by 40% maximum and 14% average as compared with the well- known dynamic queue (DQ) MAC protocol.

关键词： Wireless Network estimation algorithm Medium Access Control Active User Network Traffic

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Concatenated fibre-wireless channel identification in a multiuser CDMA environment

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IET COMMUNICATIONS 2007年第5期1卷 937-944页

作者： Pinter, S. Z. Fernando, X. N. Ryerson Univ Dept Elect & Comp Engn Toronto ON M5B 2K3 Canada

Radio-over-fibre (ROF) has received increasing attention for its ability to enable broadband wireless access. This fibre-based wireless access scheme meets the demand for broadband service by integrating the high capacity of optical networks with the flexibility of radio networks (the optical and wireless channels are concatenated with one another). There are, however, impairments that come with this appealing technology. The nonlinear distortion of the optical link and the multipath dispersion of the wireless channel are two of the major factors. In order to limit the effects of these distortions, estimation, and subsequently equalisation, of the concatenated fibre-wireless channel needs to be done. An estimation algorithm for the fibre-wireless uplink in a multiuser code division multiple access (CDMA) environment is presented using pseudonoise training sequences. It has already been shown by Fernando et al. (2001) that identification of the fibre-wireless uplink is possible in a single user CDMA environment. However, the more difficult task of identification in a multiuser spread spectrum environment, which is more realistic, is shown. In the multiuser case, the cumulative effect of multiuser interference, multipath dispersion, nonlinear distortion and noise should all be handled together which makes it more challenging. Numerical evaluations of the developed algorithm show that a good estimation of both the linear and nonlinear systems is possible in the presence of 16 independent users and an signal-to-noise ratio (SNR) of 22 dB. The estimation accuracy increases with the length of the PN sequence.

关键词： multipath dispersion multiuser CDMA environment optical network multiuser spread spectrum environment code division multiple access nonlinear distortion optical link radio-over-fibre broadband networks optical fibre networks estimation algorithm broadband wireless access scheme wireless channels concatenated fibre-wireless channel identification channel estimation multiuser channels

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Hardware implementation of real time cavity parameters identification system

Hardware implementation of real time cavity parameters ident...

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International Conference on Computer as a Tool (EUROCON 2007)

作者： Czarski, Tomasz Linczuk, Maciej Pozniak, Krzysztof Romaniuk, Ryszard Warsaw Univ Technol Inst Elect Syst Warsaw Poland

ISBN: (纸本)9781424408122

An implementation of Cavity Parameters estimation System (CPES) is presented. Main idea of the CPES is to support the LLRF - Low Level Radio Frequency system for FLASH laser in DESY. Algebraic, complex model of the LLRF system is proposed. For a given model structure the input-output relation of the real plant with unknown parameters is applied. The over-determined matrix equation is created covering the long enough measurement range with a solution according to the least squares method. A base function approximation by cubic B-spline set is applied to estimate the time-varying cavity detuning during the pulse. An implementation in DSP processor of the matrix equation solution and cavity parameters estimation algorithm is presented. A comparison between Matlab and DSP computation error is presented.

关键词： LLRF FLASH DSP estimation algorithm

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Burst format design for optimum joint estimation of Doppler-shift and Doppler-rate in packet satellite communications

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2007年第unknown期2007卷 029086-029086页

作者： Giugno, Luca Zanier, Francesca Luise, Marco Wiser Srl Wireless Syst Engn & Res I-57123 Livorno Italy Univ Pisa Dipartimento Ingn Informaz I-56122 Pisa Italy

This paper considers the problem of optimizing the burst format of packet transmission to perform enhanced-accuracy estimation of Doppler-shift and Doppler-rate of the carrier of the received signal, due to relative motion between the transmitter and the receiver. Two novel burst formats that minimize the Doppler-shift and the Doppler-rate Cramer-Rao bounds (CRBs) for the joint estimation of carrier phase/Doppler-shift and of the Doppler-rate are derived, and a data-aided (DA) estimation algorithm suitable for each optimal burst format is presented. Performance of the newly derived estimators is evaluated by analysis and by simulation, showing that such algorithms attain their relevant CRBs with very low complexity, so that they can be directly embedded into new-generation digital modems for satellite communications at low SNR.

关键词： Information System Receive Signal estimation algorithm Relative Motion System Application

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TWO OBSERVERS FOR IN-CYLINDER MASS estimation USING CYLINDER PRESSURE MEASUREMENTS

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IFAC Proceedings Volumes 2007年第10期40卷 219-226页

作者： P. Giansetti G. Colin Y. Chamaillard P. Higelin Laboratoire de Mécanique et d'Energêtique Orlêans France

To meet future pollutant emissions Standards, it is crucial to be able to estimate the cycle by cycle in-cylinder mass and the composition of the combustion chamber charge. This charge consists of residual gas from the previous cycle, fresh air and fuel. Consequently, the estimation of the fresh air mass based on total in-cylinder mass is a function of the residual gas fraction. This estimation is essential to compute the fuel mass to be injected. This paper proposes two observers, based on a physical approach, that estimate the in-cylinder mass and composition using the cylinder pressure. To test the estimator, several parameters are varied, especially the cylinder pressure offset compensation and the exhaust gases temperature.

关键词： cylinder pressure estimation algorithm in-cylinder mass estimation residual gases SI engine control

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Maximum likelihood timing and carrier synchronization in burst-mode satellite transmissions

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2007年第unknown期2007卷 065058-065058页

作者： Morelli, Michele D'Amico, Antonio A. Dept Informat Engn Via Caruso I-56100 Pisa Italy

This paper investigates the joint maximum likelihood (ML) estimation of the carrier frequency offset, timing error, and carrier phase in burst-mode satellite transmissions over an AWGN channel. The synchronization process is assisted by a training sequence appended in front of each burst and composed of alternating binary symbols. The use of this particular pilot pattern results into an estimation algorithm of a. ordable complexity that operates in a decoupled fashion. In particular, the frequency offset is measured first and independently of the other parameters. Timing and phase estimates are subsequently computed through simple closed-form expressions. The performance of the proposed scheme is investigated by computer simulation and compared with Cramer-Rao bounds. It turns out that the estimation accuracy is very close to the theoretical limits up to relatively low signal-to-noise ratios. This makes the algorithm well suited for turbo-coded transmissions operating near the Shannon limit. Copyright (c) 2007 M. Morelli and A. A. D'Amico.

关键词： estimation algorithm Carrier Frequency estimation Accuracy Carrier Phase Timing Error

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