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effective algorithm for fault discrimination and estimation of fault location in transmission lines

IET GENERATION TRANSMISSION & DISTRIBUTION 2019年第13期13卷 2789-2798页

作者： Gangolu, Suryanarayana Raja, P. Selvan, M. P. Murali, Venkata Kirthiga NIT Tiruchirappalli Elect Engn Dept Tiruchirappalli Tamil Nadu India

Sensitivity, selectivity, speed of operation and reliability of the conventional current differential protection schemes are affected and limited by the distributed shunt capacitance of high-voltage long transmission lines. In this study, a new pilot protection algorithm has been proposed based on the computation of change in shunt line admittance 'Y' during dynamic conditions using synchronised data. Therefore, it does not require a separate compensating technique to nullify the effect of line charging current in the fault detection. This scheme can quickly discriminate the internal faults and also detects the faulty phase. Also, it has an advantage of estimation of an accurate fault location. The performance of the proposed algorithm is evaluated on 400 kV, 50 Hz two-bus system as well as IEEE-39 bus 345 kV system using EMTDC/PSCAD and MATLAB simulation tools. The simulation results confirm the proposed algorithm can effectively discriminate the faults, independent of fault location, fault resistance, type of fault, series compensation lines and source impedance. Finally, a hardware experiment using National Instruments (NI) based LabVIEW platform is carried out to check the practical feasibility of the proposed algorithm.

关键词： fault diagnosis synchronisation fault location power transmission protection power transmission lines power transmission faults effective algorithm fault discrimination distributed shunt capacitance high-voltage long transmission lines pilot protection algorithm shunt line admittance dynamic conditions synchronised data separate compensating technique fault detection internal faults accurate fault location two-bus system fault resistance series compensation lines National Instruments based LabVIEW platform fault location estimation conventional current differential protection scheme reliability voltage 400 0 kV voltage 345 0 kV

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effective algorithm for Inner Forces Influence Surface of Hexahedral Elements Models

Effective Algorithm for Inner Forces Influence Surface of He...

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International Conference on Green Building, Materials and Civil Engineering (GBMCE 2011)

作者： Zhou, Xiaoyong Li, Na Xu, Bingshuang China Univ Geosci Wuhan 430074 Peoples R China HuaZhong Univ Sci & Technol Wuhan Peoples R China

ISBN: (纸本)9783037852033

Based on reciprocal theorem of work, and the physical geometry equations of finite element, the paper presented a new method to calculate influence surface of inner forces for hexahedral element finite models;it can be used to calculate directly in the solid element finite model. It possesses the characteristics of clarification and simplicity. Compared with the static method and mobile method, it can improve computing precision, and also reduce the amount of the calculation.

关键词： bridge engineering effective algorithm virtual work principle hexahedral element influence surface of inner forces

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effective algorithm for computation of the stationary distribution of multi-dimensional level-dependent Markov chains with upper block-Hessenberg structure of the generator

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2020年 366卷 112425-000页

作者： Dudin, Sergei Dudin, Alexander Kostyukova, Olga Dudina, Olga Belarusian State Univ 4 Nezavisimosti Ave Minsk 220030 BELARUS RUDN Univ Peoples Friendship Univ Russia 6 Miklukho Maklaya St Moscow 117198 Russia Natl Acad Sci Belarus Inst Math Minsk BELARUS

Multi-dimensional level-dependent Markov chains with the upper block-Hessenberg structure of the generator have found extensive applications in applied probability for solving the problems of queueing, reliability, inventory, etc. However, the problem of computing the stationary distribution of such chains is not completely solved. There is a known algorithm for multi-dimensional Asymptotically Quasi-Toeplitz Markov Chains, but, it is required a large amount of computer resources and time-consuming. In this paper, we propose a new effective algorithm that is much less time- and memory-consuming. The new algorithm can be used for analyzing any multi-dimensional Markov chain with the considered structure of the generator. To numerically demonstrate the advantages of this algorithm over the known one, we use it for analysis of a novel single-server retrial queueing system with the batch Markovian arrival process (BMAP), a finite buffer, non-persistent customers and an unreliable server. We derive a transparent ergodicity condition for this queueing system. Then, assuming that this condition is fulfilled, we apply the new algorithm and demonstrate its advantages over the known one. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Level-dependent multi-dimensional Markov chains effective algorithm Batch Markovian arrival process Unreliable service Retrial queue

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Adaptive patched L0 gradient minimisation model applied on image smoothing

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IET IMAGE PROCESSING 2018年第10期12卷 1892-1902页

作者： Ni, Kang Wu, Yiquan Nanjing Univ Aeronaut & Astronaut Coll Elect & Informat Engn Jiang Jun Rd 29 Nanjing Jiangsu Peoples R China Minist Transport Nanjing Hydraul Res Inst Key Lab Port Waterway & Sedimentat Engn Guangzhou St 223 Nanjing Jiangsu Peoples R China

L0 gradient minimisation model, one of edge-aware image smoothing method, also suffers from the stair-casing effect and images with strong textures cannot be smoothed effectively and weak edges or structures will be smoothed overly. The authors propose a method to overcome these drawbacks above. To begin with, the image is subjected to non-subsampled shearlet transform to obtain high-frequency component, and combine all high-frequency component by maximum local energy rules to obtain the high-frequency decomposition image, afterwards, introducing the data term associated with high-frequency decomposition image to keep the similarity of edge and structure between the input and smoothed image. Secondly, the patched L0 gradient minimisation model is presented for improving the description of local information, since different size of the patches has the different texture, exploiting the coefficient of variation to define the size of patch. Finally, defining the adaptive smoothing coefficient based on the gradient to make sure that the smoothing effect of the patch is optimal. The proposed model is applied to image smoothing with desirable results successfully, and the comparisons with other state-of-the-art edgepreserving image smoothing algorithms demonstrate the great performances of edge-preserving and texture smoothing.

关键词： minimisation transforms smoothing methods gradient methods edge detection image denoising image fusion image enhancement image texture Adaptive patched L0 gradient minimisation model edge-aware image smoothing method effective algorithm trivial detail stair-casing effect images strong textures weak edges structures named adaptive high-frequency component maximum local energy rules high-frequency decomposition image patch different texture adaptive smoothing coefficient smoothing effect state-of-the-art edge-preserving texture smoothing

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Retrial multi-server queuing system with PHF service time distribution as a model of a channel with unreliable transmission of information

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APPLIED MATHEMATICAL MODELLING 2019年 65卷 676-695页

作者： Dudin, Sergei Dudina, Olga Belarusian State Univ 4 Nezavisimosti Ave Minsk 220030 BELARUS Peoples Friendship Univ Russia RUDN Univ 6 Miklukho Maklaya St Moscow 117198 Russia

A multi-server retrial queue with a Markovian arrival process, as well as possible customer non-persistency and unreliable operation of servers, is analysed. The service of a customer (transmission of information) consists of a random number of phases. During a transmission, a failure can occur. The failure does not cause server breakdown or its subsequent recovery. The failure occurrence during service of a customer implies either that the departure of the customer from the server (the customer joins an orbit and retries later), the customer re-starts complete service immediately, or the customer resumes the service from the phase at which the failure occurred. The total occupation time of a server by a customer has a so-called PHF (phase-type with failures) distribution. The dynamics of the system are described by a multi-dimensional level-dependent Markov chain. An infinitesimal generator of the chain is derived. To obtain the ergodicity condition, we prove that the Markov chain belongs to the class of asymptotically quasi-Toeplitz Markov chains. Because we consider a multi-server queuing system, the dimensions of the blocks of the generator can be large. Thus, the use of a standard algorithm to find a stationary distribution of an asymptotically quasi-Toeplitz Markov chain can face problems in the stage of computer implementation. We develop a new efficient iterative algorithm for approximate computation of the stationary distribution that computes many times faster and requires much fewer computer resources than the standard algorithm. The advantages of the new algorithm and some features of the model under consideration are numerically demonstrated. (C) 2018 Elsevier Inc. All rights reserved.

关键词： Retrial multi-server queue Level-dependent Markov chain effective algorithm

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algorithms as Defendants?

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COMPUTER 2024年第7期57卷 11-14页

作者： Voas, Jeffrey Miller, Keith Univ Missouri St Louis MO 63121 USA

This EIC message ponders what can be legally done now (and in the future) to algorithms when they misbehave and create problems for the humans they were designed to serve.

关键词： Accountability Black Box effective algorithm Short Message Artificial Intelligence algorithms Deep Pockets Criminal Proceedings Good Source Of Information Issue For Years

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Rank 1 character varieties of finitely presented groups

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GEOMETRIAE DEDICATA 2018年第1期192卷 1-19页

作者： Ashley, Caleb Burelle, Jean-Philippe Lawton, Sean Univ Michigan Dept Math 530 Church St Ann Arbor MI 48109 USA Inst Hautes Etud Sci Bur 1E11 35 Route Chartres F-91440 Bures Sur Yvette France George Mason Univ Dept Math Sci 4400 Univ Dr Fairfax VA 22030 USA

Let X(Gamma,G) be the G-character variety of Gamma where G is a rank 1 complex affine algebraic group and Gamma is a finitely presentable discrete group. We describe an algorithm, which we implement in Mathematica, SageMath, and in Python, that takes a finite presentation for Gamma and produces a finite presentation of the coordinate ring of X(Gamma,G). We also provide a new description of the defining relations and local parameters of the coordinate ring when Gamma is free. Although the theorems used to create the algorithm are not new, we hope that as a well-referenced exposition with a companion computer program it will be useful for computation and experimentation with these moduli spaces.

关键词： Character variety effective algorithm Rank 1 Lie group Finitely presented group

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Joint detection of a given number of reference fragments in a quasi-periodic sequence and its partition into segments containing series of identical fragments

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Computational Mathematics and Mathematical Physics 2006年第1期46卷 165-181页

作者： Mikhailova, L.V. Sobolev Institute of Mathematics Siberian Division Russian Academy of Sciences Novosibirsk 630090 pr. Akademika Koptyuga 4 Russian Federation

The problem of joint a posteriori detection of reference fragments in a quasi-periodic sequence and its partition into segments containing series of recurring fragments from the reference tuple is solved. It is assumed that (i) an ordered reference tuple of sequences to be detected is given, (ii) the number of desired fragments is known, (iii) the index of the sequence term corresponding to the beginning of a fragment is a deterministic (not random) value, and (iv) a sequence distorted by an additive uncorrelated Gaussian noise is available for observation. It is established that the problem consists in testing a set of hypotheses about the mean of a random Gaussian vector. The cardinality of the set grows exponentially as the vector dimension (i.e., the sequence length) increases. An efficient a posteriori algorithm producing a maximum-likelihood optimal solution to the problem is substantiated. Time and space complexity bounds related to the parameters of the problem are derived. The results of numerical simulation are presented. © MAIK "Nauka/Interperiodica" (Russia), 2006.

关键词： A posteriori noise-proof processing Detecting effective algorithm Numerical sequence Partitioning Quasi-periodic fragment Series

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Outlier-robust segmentation solution - Model-based approach

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Model Assisted Statistics and Applications 2009年第3期4卷 203-213页

作者： Nowakowska, Ewa GfK Polonia 00-389 Warszawa ul. Smulikowskiego 4 Poland

Undiscovered presence of outlying observations in a dataset is likely to result in misleading conclusions. The problem is vital for cluster analysis, where undetected contamination usually causes significant decrease in stability and reproducibility, leading to distortions in the segment profiles. Based on the ML-approach proposed by Gallegos and Ritter [9], we have implemented an effective algorithm, which allows for simultaneous detection of outliers and estimation of the structure in the remaining data. In contrast to standard pre clustering procedures, it detects contamination in relation to the identified data structure. This paper compares the performance of the new robust algorithm with a standard pre clustering outlier detection procedure by means of simulation study. The results indicate that the robust method in certain situations may lead to more distinct cluster structure and less biased segment profiles. The method applications in market research are also discussed. © 2009 IOS Press. All rights reserved.

关键词： Between-segments heterogeneity Cluster analysis effective algorithm Maximum likelihood estimation Outlying observations Reproducibility Segmentation research Stability Within-segments homogeneity

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Comparison of the efficiency of numerical algorithms for solving the inverse kinematics problem of redundant serial-link robots 2nd

Comparison of the efficiency of numerical algorithms for sol...

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2nd Annual International Conference on Material, Machines and Methods for Sustainable Development, MMMS 2020

作者： Duong, Xuan Bien Chu, Anh My Le, Chi Hieu Nguyen, Tien Anh Vu, Minh Duc Le, Anh Le Quy Don Technical University Hanoi Viet Nam Faculty of Science and Engineering University of Greenwich London United Kingdom

ISBN: (纸本)9783030696092

This paper presents the results of the comparison of the use efficiency between two numerical algorithms which are the Adjust of Generalized Vector (AGV) and the Closed-Loop Inverse kinematics (CLIK) method when solving the inverse kinematics problem (IK) for the redundant serial-link robots. AGV method is developed based on the Taylor expansion method but adjusted to improve the accuracy of the IK solution. CLIK is a numerical method that is built as a closed-loop kinematics control system with the position error of the end-effector point in the workspace. The industrial SCARA robots with 4 degrees of freedom (DOF) including rotational and translational joints and PA10-7C industrial robots with 7-DOF are used to illustrate the effectiveness of the algorithms. The comparison results are expressed through the obtained joint variables values, the position error of the end-effector point in the workspace, and the deviation values of joint variables between the two methods. The results of this study allow evaluating the effectiveness of these methods for solving the IK and serve as the basis for choosing a suitable method for each specific robot configuration. However, this article has not considered the effectiveness of the methods mentioned above for other types of robots. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021.

关键词： Closed-loop feedback effective algorithm Inverse kinematics Redundant robots

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