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Fault Diagnosis for RPMs Based on Novel Weighted multi-scale Fractional Permutation Entropy Improved by multi-scale algorithm and PSO

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2024年第8期73卷 11072-11081页

作者： Sun, Yongkui Cao, Yuan Li, Peng Su, Shuai Beijing Jiaotong Univ Natl Engn Res Ctr Rail Transportat Operat Control Sch Automat & Intelligence Beijing 100044 Peoples R China Beijing Jiaotong Univ Sch Automat & Intelligence Beijing 100044 Peoples R China Beijing Jiaotong Univ Frontiers Sci Ctr Smart High speed Railway Syst Beijing 100044 Peoples R China

Railway point machines (RPMs) are important to make the trains operate efficiently and safely. Thus it is vital to research fault diagnosis. Nowadays contactless fault diagnosis attracts more and more attention. In this paper, a sound-based contactless fault diagnosis method is proposed for RPMs by using novel weighted multi-scale fractional permutation entropy (WMFPE) realized by multi-scale algorithm and synchronous optimization strategy. Firstly, to enhance the fault discrimination ability, novel feature named multi-scale fractional permutation entropy (MFPE) is proposed by introducing the idea of fractional calculus to multi-scale permutation entropy (MPE), which is a more powerful tool. Secondly, considering the effect difference of different permutation, new feature named WMFPE is proposed by introducing weight idea. Then, a multi-scale algorithm is developed to reduce information loss during the coarse-grain process, which can improve the diagnosis accuracy. Finally, a synchronous optimization strategy is proposed to optimize the weights of WMFPE and hyperparameters of support vector machine (SVM) at the same time using particle swarm optimization (PSO). The effectiveness of the proposed method is verified by comparison experiments. Results show the proposed method performs best on fault diagnosis of RPMs with an overall accuracy of 99.33% on reverse-normal and normal-reverse switching processes. The proposed method opens a new window for fault diagnosis on RPMs.

关键词： Entropy Fault diagnosis Rail transportation Support vector machines Fractional calculus Feature extraction Employee welfare Railway point machines (RPMs) fault diagnosis weighted multi-scale fractional permutation entropy (WMFPE) multi-scale algorithm

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A multi-scale algorithm for the NISAR mission high-resolution soil moisture product

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REMOTE SENSING OF ENVIRONMENT 2023年第1期295卷

作者： Lal, Preet Singh, Gurjeet Das, Narendra N. Entekhabi, Dara Lohman, Rowena Colliander, Andreas Pandey, Dharmendra Kumar Setia, R. K. Michigan State Univ Dept Civil & Environm Engn E Lansing MI 48824 USA Michigan State Univ Dept Biosyst & Agr Engn E Lansing MI USA MIT Dept Civil & Environm Engn Cambridge MA USA Cornell Univ Earth & Atmospher Sci Ithaca NY USA CALTECH Jet Prop Lab Pasadena CA USA ISRO Space Applicat Ctr Ahmadabad India Punjab Remote Sensing Ctr Ludhiana Punjab India

This study proposes a multi-scale soil moisture algorithm for the upcoming NASA-ISRO SAR (NISAR) mission to estimate high-resolution (200 [m]) soil moisture (the water content of the soil). The algorithm takes advantage of the high-resolution (-10 [m]) synthetic aperture radar (SAR) backscatter and coarse resolution modeled/ reanalysis soil moisture products (-9 [km]) to create a high-resolution (200 [m]) soil moisture product at a global extent. The end goal of the algorithm is to remove dependencies on any complex modeling, tedious retrieval steps, or multiple ancillary data needs, and subsequently decrease the degrees of freedom to achieve optimal accuracy in soil moisture retrievals. The use of modeled/reanalysis soil moisture products with high temporal resolution gives an added advantage in reducing the temporal mismatch between the two different inputs used in the algorithm. In this study, the proposed algorithm is tested using L-band UAVSAR backscatter (& sigma;degrees) data and Advanced Land Observing Satellite-2 (ALOS-2) SAR & sigma;degrees as a substitute for the NISAR L-band SAR observations. The algorithm uses the L-band SAR & sigma;degrees to disaggregate coarse resolution (-9 [km]) reanalysis soil moisture of the European Centre for Medium-Range Weather Forecast (ECMWF) to a high-resolution of-200 [m] soil moisture product. The potential of the algorithm is demonstrated over three sites in different hydro climatic regions of the world, such as India, the USA, and Canada. The high-resolution soil moisture estimates were compared with the in-situ soil moisture measurements available for three sites (North India, Southern California, and Carman, Manitoba, Canada). In North India, in-situ measurements are from paddy crops with high vegetation water content, the unbiased root-mean-square-error (ubRMSE) for the high-resolution soil moisture retrievals was found to be 0.036 [m3/m3] with a bias of-0.051 [m3/m3]. For the southern California site, the validatio

关键词： High-resolution Soil moisture multi-scale algorithm NISAR ALOS-2 UAVSAR ECMWF SMAPVEX-12

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A multi-scale algorithm for dislocation creep at elevated temperatures

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Theoretical & Applied Mechanics Letters 2021年第1期11卷 42-46页

作者： Lichao Yuan Yujie Wei State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

Dislocation creep at elevated temperatures plays an important role for plastic deformation in crystalline *** using traditional discrete dislocation dynamics(DDD)to capture this process,we often need to update the forces on N dislocations involving~N 2 *** this letter,we introduce a multi-scale algorithm to speed up the calculations by dividing a sample of interest into sub-domain grids:dislocations within a characteristic area interact following the conventional way,but their interaction with dislocations in other grids are simplified by lumping all dislocations in another grid as a super *** a multi-scale algorithm lowers the computational load to~N *** employed this algorithm to model dislocation creep in Al-Mg *** simulation leads to a power-law creep rate in consistent with experimental *** stress exponent of the power-law creep is a resultant of dislocations climb for~5 and viscous dislocations glide for~3.

关键词： multi-scale algorithm Dislocation glide Dislocation climb High temperature creep Dislocation dynamics

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A Research on multi-scale Breakpoint Repair algorithm oflnfrared Vein Image Based on Vein Direction

A Research on Multi-Scale Breakpoint Repair Algorithm oflnfr...

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2020 International Conference on Artificial Intelligence and Computer Engineering, ICAICE 2020

作者： Yang, Kai Wang, Zhihui Xu, Benchao Sun, Xuege Institute of Wireless Power Transfer Technology Chongqing University Chongqing China

ISBN: (纸本)9781728191461

Extracted veins often have a large number of breakpoints, losing the continuity of veins after vein image binarization with image algorithms such as OTSU algorithm. In this paper, a multi-scale breakpoint repair algorithm based on vein direction is proposed. Firstly, the overall vein direction is obtained by using the designed multi-direction matrix on preprocessed image. Then the vein image is binarized by bidirectional valley recognition algorithm. Finally, the vein breakpoint is connected by the proposed multi-scale vein breakpoint repair algorithm. The experimental results show that the multi-scale breakpoint repair algorithm based on vein direction can repair breakpoints well and improve the continuity of veins. © 2020 IEEE.

关键词： breakpoint repair infrared vein image multi-scale algorithm vein direction

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Boundary element study of wave impact on a vertical wall with air entrapment

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ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS 2018年 90卷 26-38页

作者： Song, Bingyue Zhang, Chongwei Kunming Univ Sci & Technol Dept Elect Power Engn Kunming 650504 Yunnan Peoples R China Dalian Univ Technol State Key Lab Coastal & Offshore Engn Dalian 116023 Peoples R China

Effect of the air entrapped between an overturning wave and a vertical wall plays an essential role in the physical process of wave impact. However, due to complexity of both the physical phenomena and numerical techniques, conventional simulations with boundary element method (BEM) can only deal with the wave overturning stage, and calculations have to be terminated before the wave front impacts on the wall. This study aims to achieve the complete process simulation of wave impact with air entrapment using BEM. The key idea is to introduce a multi scale algorithm with the help of a stretched coordinate system for the local impact zone. Interesting phenomena are observed indicating effects of the entrapped air on wave impact dynamics. In particular, free inner jets are found to form periodically inside the entrapped air cavity. The free jet has the trend to lead to the division of the cavity, indicating an initial bubble generation during wave impact. Effects of the air pressure on the impact process with air entrapment are also studied, where an analytical deduction based on the conservation law of conservation is used to explain the findings. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Breaking wave impact Air entrapment multi-scale algorithm Stretched coordinate system Boundary element method

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A Fast Methodology for Topology Optimizations of Electromagnetic Devices

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IEEE TRANSACTIONS ON MAGNETICS 2017年第6期53卷 1-4页

作者： Ho, S. L. Yang, Shiyou Bai, Yanan Hong Kong Polytech Univ Dept Elect Engn Hong Kong Hong Kong Peoples R China Zhejiang Univ Coll Elect Engn Hangzhou 310027 Zhejiang Peoples R China

To alleviate the excessive computational burden involved in topology optimizations, an efficient methodology for topology optimization is proposed. In the proposed methodology, a multi-scale on/off method is designed to avoid using infinite number of decision parameters;and a stochastic approximation method is employed to minimize the computational costs when computing the sensitivity information. Numerical results are reported to showcase the merits of the proposed methodology.

关键词： multi-scale algorithm on/off method sensitivity information topology optimization

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A Fast Methodology for Topology Optimizations of Electromagnetic Devices 17

A Fast Methodology for Topology Optimizations of Electromagn...

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17th IEEE Biennial Conference on Electromagnetic Field Computation (IEEE CEFC)

作者： Ho, S. L. Yang, Shiyou Bai, Yanan Hong Kong Polytech Univ Dept Elect Engn Hong Kong Hong Kong Peoples R China Zhejiang Univ Coll Elect Engn Hangzhou 310027 Peoples R China

ISBN: (纸本)9781509010325

To alleviate the excessive computational burden on topology optimizations, an efficient methodology on topology optimization is proposed. In the proposed methodology, a multi-scale ON/OFF method is designed to avoid using infinite number of decision parameters;and a stochastic approximation method is employed to minimize the computational costs when computing the sensitivity information. Numerical results are reported to showcase the merits of the proposed methodology.

关键词： multi-scale algorithm ON/OFF method sensitivity information topology optimization

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Fast layout computation of clustered networks: algorithmic advances and experimental analysis

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INFORMATION SCIENCES 2014年 260卷 185-199页

作者： Didimo, Walter Montecchiani, Fabrizio Univ Perugia Dipartimento Ingn Elettron & Informaz I-06100 Perugia Italy

The visual analysis of large and complex relational data sets is a growing need in many application domains, such as social sciences, biology, computer networks, and software engineering. In this respect, the capability of quickly computing two-dimensional layouts of hierarchically clustered networks plays an important role and should be a major requirement of many graph visualization systems. We present algorithmic and experimental advances on the subject, namely: (i) we propose a new drawing algorithm that combines space-filling and fast force-directed methods;it runs in O(n log n + m) time, where n and m are the number of vertices and edges of the network, respectively. This running time does not depend on the number of clusters, thus the algorithm guarantees good time performance independently of the structure of the cluster hierarchy. As a further advantage, the algorithm can be easily parallelized. (ii) We discuss the results of an experimental analysis aimed at understanding which clustering algorithms can be used in combination with our visualization technique to generate better quality drawings for small-world and scale-free networks of medium and large size. As far as we know, no previous similar experiments have been done to this aim. (C) 2013 Elsevier Inc. All rights reserved.

关键词： Graph drawing Network visualization Hierarchical clustering multi-scale algorithm Force-directed algorithm Treemap algorithm

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multi-scale and first derivative analysis for edge detection in TEM images

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4th International Conference on Image Analysis and Recognition

作者： Coudray, Nicolas Buessler, Jean-Luc Kihl, Hubert Urban, Jean-Philippe Grp TROP Lab MIPS F-68093 Mulhouse France

ISBN: (纸本)9783540742586

Transmission electron microscope images of biological membranes are difficult to segment because they are low-contrasted images with heterogeneous gray levels. Added to that are the many possible types of membranes, the variable degree of aggregation, and the negative staining of the sample. We therefore develop a multi-scale approach to detect the edges at the appropriate scales. For these images, the study of the amplitude of the first derivative through the scales simplifies the feature tracking and the scale selection. A scale-adapted threshold is automatically applied to gradient images to progressively segment edges through the scales. The edges found at the different scales are then combined into a gradient-like image. The watershed algorithm is finally applied to segment the image into homogeneous regions, automatically selecting the edges found at the finest resolution.

关键词： multi-scale algorithm edge detection first derivative method TEM images segmentation

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Affine invariant segmentation by variational method

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SIAM JOURNAL ON APPLIED MATHEMATICS 1996年第1期56卷 294-325页

作者： Ballester, C Caselles, V Gonzalez, M UNIV ILLES BALEARS DEPT MATEMAT & INFORMAT E-07071 PALMA DE MALLORCA SPAIN

Affine invariance, viewed as a simplified projective invariance, is an essential requirement for analysis of natural scenes. We propose an affine invariant analogue of Mumford and Shah energy functional to segment images and we discuss it. We present a simple multiscale algorithm to minimize it: based on region growing methods, and we display our first numerical experiments.

关键词： image segmentation affine invariance variational method region growing multi-scale algorithm

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