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Fault diagnosis for track circuit using AOK-TFRs and AGA

CONTROL ENGINEERING PRACTICE 2012年第12期20卷 1270-1280页

作者： Zhao Lin-Hai Wu Jian-Ping Ran Yi-Kui Beijing Jiaotong Univ Sch Elect & Informat Engn Beijing 100044 Peoples R China Univ Southampton Transportat Res Grp Southampton Hants England WSP Grp London England Beijing Univ Posts & Telecommun Beijing 100088 Peoples R China

This paper presents a collaborative fault diagnosis system for compensation capacitor in track circuit using adaptive optimal kernel time-frequency representations (AOK-TFRs) and adaptive genetic algorithm (AGA) based on train operational data recorded in cab signal. First, AOK-TFRs technique is applied for single compensation capacitor fault diagnosis. To deal with multiple faults, the AGA based method is introduced, however, with a relatively low efficiency of diagnosis. According to the characteristics of both methods, a collaborative fault diagnosis system is established. Experiments show that the system greatly improves the diagnosis efficiency and can be used successfully. (c) 2012 Elsevier Ltd. All rights reserved.

关键词： Fault diagnosis Railways Time-frequency representation Genetic algorithms interpolation algorithms Transmission line theory

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AN APPROACHING FOURIER ANALYSIS OF THE RELAXATION EFFECT ON THE SIMPLE ALGORITHM

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NUMERICAL HEAT TRANSFER PART A-APPLICATIONS 2012年第6期62卷 499-511页

作者： Wang, F. Li, Y. T. Wuhan Univ State Key Lab Water Resources & Hydropower Engn S Wuhan 430072 Hubei Province Peoples R China

The Fourier decomposition is employed to derive the error amplification matrix for the SIMPLE algorithm implemented on a collocated grid with the Rhie-Chow interpolation method incorporated, and an approaching method is developed to study the effect of relaxation factors on the convergence behaviors of SIMPLE based on characteristic analysis of the lowest and highest frequency errors. The study indicates that convergence can be guaranteed by damping out the highest and lowest frequencies with conditional combinations of both factors. In the case of convergence, the optimum convergence rate almost depends on the velocity relaxation factor, and a relatively larger velocity factor can accelerate the optimal rate.

关键词： FOURIER analysis STOCHASTIC convergence COMBINATIONS (Mathematics) interpolation algorithms CHARACTERISTIC functions ERROR analysis (Mathematics)

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Provably Convergent Multifidelity Optimization Algorithm Not Requiring High-Fidelity Derivatives

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AIAA JOURNAL 2012年第5期50卷 1079-1089页

作者： March, Andrew Willcox, Karen MIT Dept Aeronaut & Astronaut Cambridge MA 02139 USA

This paper presents a provably convergent multifidelity optimization algorithm for unconstrained problems that does not require high-fidelity gradients. The method uses a radial basis function interpolation to capture the error between a high-fidelity function and a low-fidelity function. The error interpolation is added to the low-fidelity function to create a surrogate model of the high-fidelity function in the neighborhood of a trust region. When appropriately distributed spatial calibration points are used, the low-fidelity function and radial basis function interpolation generate a fully linear model. This condition is sufficient to prove convergence in a trust region framework. In the case when there are multiple lower-fidelity models, the predictions of all calibrated lower-fidelity models can be combined with a maximum likelihood estimator constructed using kriging variance estimates from the radial basis function models. This procedure allows for flexibility in sampling lower-fidelity functions, does not alter the convergence proof of the optimization algorithm, and is shown to be robust to poor low-fidelity information. The algorithm is compared with a single-fidelity quasi-Newton algorithm and two first-order consistent multifidelity trust region algorithms. For simple functions the quasi-Newton algorithm uses slightly fewer high-fidelity function evaluations;however, for more complex supersonic airfoil design problems it uses significantly more. In all cases tested, our radial basis function calibration approach uses fewer high-fidelity function evaluations when compared with first-order consistent trust region schemes.

关键词： algorithms interpolation algorithms CALIBRATION STOCHASTIC convergence MATHEMATICAL models

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High accuracy Hough transform based on butterfly symmetry

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ELECTRONICS LETTERS 2012年第4期48卷 199-U200页

作者： Du, Shengzhi Tu, Chunling Sun, Mingwei Univ S Africa Dept Elect & Min Engn ZA-0001 Pretoria South Africa Tshwane Univ Technol Dept Elect Engn Pretoria South Africa Nankai Univ Dept Automat Tianjin 300071 Peoples R China

The theoretical symmetry in Hough transform (HT) butterflies is addressed. The reason the symmetry is damaged in real HT butterflies is analysed and employed to propose a high accuracy HT. Experiment demonstrates that... 详细信息

关键词： COMPUTER vision interpolation algorithms GAUSSIAN distribution PREDICATE calculus ROBUST control

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Result-consistent counter sampling scheme for coarse-fine TDCs

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ELECTRONICS LETTERS 2012年第19期48卷 1195-U43页

作者： Michalik, P. Fernandez, D. Madrenas, J. Univ Politecn Cataluna Dept Engn Elect Barcelona Spain Baolab Microsyst Terrassa Spain

A novel sampling scheme for coarse-fine time-to-digital converters (TDCs), whose architecture commonly comprises a synchronous counter as a coarse part and delay-line based phase interpolator as a fine part, is proposed. The presented approach eliminates any error in the coarse counter and is superior in terms of mean time between failures as well as complexity, area and power consumption in comparison to previously reported solutions.

关键词： Time series analysis Delay lines Check digit schemes Performance of analog-to-digital converters Bit error rate measurement interpolation algorithms Computational complexity

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NSE abundance data

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ATOMIC DATA AND NUCLEAR DATA TABLES 2012年第4期98卷 852-861页

作者： Odrzywolek, Andrzej Jagiellonian Univ M Smoluchowski Inst Phys PL-30059 Krakow Poland

A novel method of calculating nuclear statistical equilibrium (NSE) is presented. Basic equations are carefully solved using arbitrary precision arithmetic. A special interpolation procedure is then used to retrieve all abundances using tabulated results for neutrons and protons, together with basic nuclear data. Proton and neutron abundance tables, basic nuclear data, and partition functions for nuclides used in the calculations are provided. A simple interpolation algorithm using pre-calculated p and n abundances tabulated as functions of kT, rho and Y-e is outlined. Unique properties of this method are: (1) ability to pick up out of NSE selected nuclei only, (2) computational time scaling linearly with number of re-calculated abundances, (3) relatively small amount of stored data: only two large tables, (4) slightly faster than solving the NSE equations using traditional Newton-Raphson methods for small networks (few tens of species): superior for huge (800-3000) networks, (5) does not require initial guess: works well on random input, (6) can be tailored to specific application, (7) ability to use third-party NSE solvers to obtain fully compatible tables, and (8) encapsulation of the NSE code for bug-free calculations. A range of applications for this approach is possible: covering tests of traditional NSE Newton-Raphson codes, generating starting values, code-to-code verification, and possible replacement of the old legacy procedures in supernova simulations. (C) 2012 Elsevier Inc. All rights reserved.

关键词： COSMIC abundances EQUILIBRIUM ARITHMETIC NEUTRONS PROTONS NUCLIDES interpolation algorithms NUCLEAR research

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Creating a Continuous Topography of Performance From Discrete Sports Actions

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IFAC Proceedings Volumes 2012年第2期45卷 814-818页

作者： Michael Stöckl Martin Lames Technical University of Munich Munich 80992 Germany

Abstract Nowadays, in many sports discrete data describing actions of athletes are collected in order to analyze performance. Performance analysis using these data usually is based on creating categories by which the quality of the performance of athletes in a certain sport can be described. The definitions of these categories often only take a few circumstances or just the most important one into account which influence the performance of an athlete. By calculating continuous topographies of representative performances of the field, respectively all participating athletes, this method of classifying performances can be broken up and performances are put in context of the place where they occurred, in context of the internal and external circumstances which influence the athlete's performance, with respect to the performance of other athletes in that area. Based on the collected data such topographies are calculated using an exponential smoothing algorithm and by means of spline interpolation. The resulting three dimensional and two dimensional visualizations of such a topography show that artificial, discrete categories, which are usually shaped like geometrical figures, often circles or rectangles, are not appropriate for performance analysis because the quality of performance even within these categories is mostly varying too much. Furthermore, the results reveal that topographies of representative performance of the field are usually not shaped like geometric figures, but rather are more chaotically shaped depending on the field's real performance. Thus, continuous topographies of performance provide the opportunity to analyze performance with respect to a real representative performance in any area.

关键词： Sports Performance Analysis Discrete Measurements Continuous Topography Exponential Smoothing interpolation algorithms Splines

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Scattered and track data interpolation using an efficient strip searching procedure

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APPLIED MATHEMATICS AND COMPUTATION 2011年第12期217卷 5949-5966页

作者： Allasia, G. Besenghi, R. Cavoretto, R. De Rossi, A. Univ Turin Dept Math I-10123 Turin Italy

A new local algorithm for bivariate interpolation of large sets of scattered and track data is presented. The method, which changes partially depending on the kind of data, is based on the partition of the interpolation domain in a suitable number of parallel strips, and, starting from these, on the construction for any data point of a square neighbourhood containing a convenient number of data points. Then, the well-known modified Shepard's formula for surface interpolation is applied with some effective improvements. The proposed algorithm is very fast, owing to the optimal nearest neighbour searching, and achieves good accuracy. Computational cost and storage requirements are analyzed. Moreover, the efficiency and reliability of the algorithm are shown by several numerical tests, also performed by Renka's algorithm for a comparison. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Continuous surface modelling interpolation algorithms Radial basis functions Scattered and track data Shepard's formulas

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The Nonlocal p-Laplacian Evolution for Image interpolation

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MATHEMATICAL PROBLEMS IN ENGINEERING 2011年第1期2011卷 1-11页

作者： Zhan, Yi Chongqing Technol & Business Univ Coll Math & Stat Chongqing 400067 Peoples R China

This paper presents an image interpolation model with nonlocal p-Laplacian regularization. The nonlocal p-Laplacian regularization overcomes the drawback of the partial differential equation (PDE) proposed by Belahmidi and Guichard (2004) that image density diffuses in the directions pointed by local gradient. The grey values of images diffuse along image feature direction not gradient direction under the control of the proposed model, that is, minimal smoothing in the directions across the image features and maximal smoothing in the directions along the image features. The total regularizer combines the advantages of nonlocal p-Laplacian regularization and total variation (TV) regularization (preserving discontinuities and 1D image structures). The derived model efficiently reconstructs the real image, leading to a natural interpolation, with reduced blurring and staircase artifacts. We present experimental results that prove the potential and efficacy of the method.

关键词： LAPLACIAN operator interpolation algorithms PARTIAL differential equations IMAGE analysis SMOOTHING (Numerical analysis)

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Three-dimensional synthetic turbulence constructed by spatially randomized fractal interpolation

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Physical Review E 2011年第2期84卷 026328-026328页

作者： Zhi-Xiong Zhang Ke-Qi Ding Yi-Peng Shi Zhen-Su She State Key Laboratory of Turbulence and Complex Systems and College of Engineering Peking University Beijing 100871 P.R. China Center for Applied Physics and Technology Peking University Beijing 100871 P.R. China

A spatially randomized fractal interpolation algorithm to construct three-dimensional synthetic turbulence from original coarse field is reported. As in the one-dimensional case by Ding et al.(Phys. Rev. E 82, 036311, 2010), during the fractal interpolation, positions mapping between large and small scale cubes are chosen randomly, and the stretching factors are drawn from a log-Poisson random multiplicative process. A linear combination function defined as the base part in fractal interpolation and a theoretical energy spectrum model for fully developed turbulence are introduced into the procedure. Statistical analysis shows that the synthetic field displays some properties very close to the direct numeric simulated field, such as probability distributions of velocity, velocity gradient, velocity increment, and the anomalous scaling behavior of the longitude velocity structure functions, which follows the SL94 model precisely. After a short time using direct numeric simulation with the synthetic field as initial data, the typical local dynamical structures described by the teardrop shape of the Q-R plane for empirical turbulence can be reproduced.

关键词： interpolation algorithms TURBULENCE APPROXIMATION theory SPEED LARGE eddy simulation models

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