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Theoretical Parameter Design Method of SFCL for Concurrent Commutation Failure Inhibition in SFCL-Segmented Multi-Infeed LCC-HVDC Systems

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IEEE TRANSACTIONS ON POWER SYSTEMS 2020年第3期35卷 1741-1757页

作者： Xiao, Hao Li, Yinhong Duan, Xianzhong Univ Manitoba Dept Elect & Comp Engn Winnipeg MB R3T 2N2 Canada Huazhong Univ Sci & Technol Sch Elect & Elect Engn State Key Lab Adv Electromagnet Engn & Technol Hubei Elect Power Secur & High Efficiency Key Lab Wuhan 430074 Peoples R China

Earlier works have reported the emerging fault current limiter (FCL) segmentation technique to mitigate concurrent commutation failure (CF) under ac faults in multi-infeed LCC-HVDC systems. However, the FCL's parameter is determined by the electromagnetic transient (EMT) simulation based method, which will lead to enormous workload and long computation time. Moreover, the subsequent CF after ac faults clearance has been ignored. Thus, this paper proposes a theoretical parameter design method of superconducting FCL (SFCL) for concurrent CF inhibition in SFCL-segmented multi-infeed LCC-HVDC systems. Firstly, a comprehensive evaluation approach of CF performance is introduced considering not only the voltage depression and distortion induced concurrent CFs but also the subsequent CF. This can give a more comprehensive CF evaluation than earlier works since the subsequent CF is considered in this approach. Secondly, three SFCL's parameter related evaluation indices, which can assess the SFCL's impact on the abovementioned three types of CF, are proposed to develop the proposed method based on the comprehensive CF evaluation approach. Compared to the simulation based method, the proposed method is implemented more efficiently without EMT simulations, and more effectively with the subsequent CF considered. Finally, the simulations based on dual-infeed and tri-infeed LCC-HVDC systems validate the proposed method.

关键词： Inverters Design methodology HVDC transmission Depression Mathematical model Distortion Resistance Commutation failure (CF) multi-infeed LCC-HVDC system parameter design segmentation technique superconducting fault current limiter (SFCL)

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A Standing-Wave Microstrip Array Antenna

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 2011年第12期59卷 4858-4861页

作者： Lakshmanan, Anand Lee, Choon Sae So Methodist Univ Dept Elect Engn Dallas TX 75275 USA

The design and analysis of a single-layer standing-wave microstrip array antenna are presented. No quarter-wave transformers or power dividers are present in the design. The main emphasis of this paper is on the multiple reflections in the feedline causing a standing-wave of a higher-order mode. As in the radiating patches of the array, the feedline resonates as well. So the array is treated as an arbitrarily-shaped microstrip antenna and the generalized cavity model is applied for analysis due to its simplicity and physical insight. The accuracy of the model is verified by simulation and experiment. Spurious radiations and manufacturing difficulties can be minimized in such single-layer standing-wave designs when compared to corporate-fed traveling-wave structures. The scheme offers good potential for building large arrays for high-gain applications.

关键词： Antenna array feeds cavity feeding cavity model microstrip arrays segmentation technique

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Boundary domain integral method for high Reynolds viscous fluid flows in complex planar geometries

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2005年第39-41期194卷 4196-4220页

作者： Hribersek, M Skerget, L Univ Maribor Fac Mech Engn Lab Computat Fluid Dynam Inst Power Proc & Environm Engn SI-2000 Maribor Slovenia

The article presents new developments in boundary domain integral method (BDIM) for computation of viscous fluid flows, governed by the Navier-Stokes equations. The BDIM algorithm uses velocity-vorticity formulation and is based on Poisson velocity equation for flow kinematics. This results in accurate determination of boundary vorticity values, a crucial step in constructing an accurate numerical algorithm for computation of flows in complex geometries, i.e. geometries with sharp corners. The domain velocity computations are done by the segmentation technique using large segments. After solving the kinematics equation the vorticity transport equation is solved using macro-element approach. This enables the use of macro-element based diffusion-convection fundamental solution, a key factor in assuring accuracy of computations for high Reynolds value laminar flows. The versatility and accuracy of the proposed numerical algorithm is shown for several test problems, including the standard driven cavity together with the driven cavity flow in an L shaped cavity and flow in a Z shaped channel. The values of Reynolds number reach 10,000 for driven cavity and 7500 for L shaped driven cavity, whereas the Z shaped channel flow is computed up to Re = 400. The comparison of computational results shows that the developed algorithm is capable of accurate resolution of flow fields in complex geometries. (c) 2004 Elsevier B.V. All rights reserved.

关键词： boundary element algorithms incompressible viscous fluid Navier-Stokes equations velocity-vorticity formulation segmentation technique driven cavity flow

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An Intrinsic Circuit Model for Multiple Vias in an Irregular Plate Pair Through Rigorous Electromagnetic Analysis

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND techniqueS 2010年第8期58卷 2251-2265页

作者： Zhang, Yao-Jiang Fan, Jun Missouri Univ Sci & Technol Electromagnet Compatibil Lab Dept Elect & Comp Engn Rolla MO 65409 USA

An irregular plate pair with multiple vias is analyzed by the segmentation method that divides the plate pair into a plate domain and via domains. In the via domains, all the parallel-plate modes are considered, while in the plate domain, only the propagating modes are included to account for the coupling among vias and the reflection from plate edges. Boundary conditions at both vias and plate edges are enforced and all parasitic components of via circuit are expressed analytically in terms of parallel-plate modes. The work presented in this paper indicates that a previous physics-based via circuit model from intuition is a low-frequency approximation. Analytical and numerical simulations, as well as measurements, have been used to validate the intrinsic via circuit model.

关键词： Intrinsic via circuit model parallel-plate modes physics-based via circuit model segmentation technique signal and power integrity

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Efficient analysis and experimental verification of substrate-integrated slab waveguides for wideband microwave applications

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2005年第3期15卷 296-306页

作者： Bozzi, M Deslandes, D Arcioni, P Perregrini, L Wu, K Conciauro, G Univ Pavia Dept Elect I-27100 Pavia Italy Ecole Polytech Poly Grames Res Ctr Montreal PQ H3C 3A7 Canada

This article presents a substrate integrated waveguide, named the substrate-integrated slab waveguide (SISW), which exhibits a wide operation bandwidth. It consists of an integrated rectangular waveguide filled with a periodically perforated dielectric medium. An efficient procedure has been developed for the calculation of the dispersion diagram of SISWs, based on the Floquet theorem, in conjunction with the segmentation technique and the boundary-integral-resonant-mode-expansion (BI-RME) method. Numerical and experimental results confirm the performance of these waveguides and the efficiency of the analysis method. (c) 2005 Wiley Periodicals, Inc.

关键词： dispersion diagram generalized admittance matrix integrated waveguides segmentation technique slab waveguides

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Analysis of Nonstationary Emissions for Efficient Characterization of Stochastic EM Fields

Analysis of Nonstationary Emissions for Efficient Characteri...

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International Symposium on Electromagnetic Compatibility (EMC EUROPE)

作者： Baharuddin, M. H. Smartt, C. Maricar, M. I. Thomas, D. W. P. Gradoni, G. Creagh, S. C. Tanner, G. Univ Nottingham George Green Inst Electromagnet Res Nottingham NG7 2RD England Univ Kebangsaan Malaysia Ctr Adv Elect & Commun Engn Bangi 43600 Malaysia Univ Nottingham Sch Math Sci Nottingham NG7 2RD England

ISBN: (纸本)9781467396981

A statistical approach using field-field correlation functions which is obtained from two-probe time domain measurement is used to characterize the radiation from complex devices. The time-frequency analysis provided by the measurement data has shown that significant emissions may only occur for a few percent of the time and a piecewise stationary model of emissions may be most appropriate. In this paper, a sorting technique is applied to short time segments of the nonstationary time-domain data provided by the measurements. These short time segments are sorted into groups according to the characteristics of the emissions, i.e. different emission processes, with the assumption that the stochastic emissions is stationary within each group (process). The ensemble of time segments associated with each group may then be used to obtain the field-field correlations for each process. Results of the analysis give promising insights into how to characterize complex and time dependent systems.

关键词： nonstationary time domain data radiated emissions printed circuit boards piecewise stationary data time domain measurement segmentation technique sorting technique

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segmentation for touching Thai typewrittens

Segmentation for touching Thai typewrittens

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IEEE Region 10 Conference on Analog and Digital techniques in Electrical Engineering

作者： Watcharabutsarakham, S Natl Elect & Comp Technol Ctr Pathum Thani 12120 Thailand

ISBN: (纸本)0780385608

Thai characters is very in size and position in sentences and Thai word is composed of consonants, vowels and tones. Touching characters can occur both horizontal and vertical directions. This paper proposes a segmentation technique for touching Thai typewrittens. The proposed uses structural characteristics to detect suitable segmentation points in both horizontal and vertical directions. The segmentation process consists of 4 steps: line classification, zone identification, touching type and segmentation type. The proposed segmentation technique tested both electronic typewriters and manual portable typewriters. The segmentation accuracy of 94% has been obtained for 100 sentences of typewritten thesis documents.

关键词： image segmentation typewriters image classification touching Thai typewrittens Thai characters segmentation technique line classification zone identification touching type segmentation type electronic typewriters manual portable typewriters

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Heuristic approach for license plate detection

Heuristic approach for license plate detection

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IEEE Conference on Advanced Video and Signal Based Surveillance

作者： Dubey, P Nalt Sci & Technol Dev Agcy Natl Elect & Comp Technol Ctr Pathum Thani 12120 Thailand

ISBN: (纸本)0780393856

The license plate detection is one of the most important processes in License Plate Recognition (LPR) System. A number of techniques have been proposed in research literatures. Among the most promising techniques is text locating-based technique. However, in a complex scene the technique creates too many candidate regions with noisy background which result in segmentation difficulty. Toward the text locating approach, this paper presents a new license plate detection and segmentation technique. Improving on the existing technique, it creates cleaner connected regions by using our new morphological approach. The searching and segmentation technique proposed here is also efficient for this very application.

关键词： image recognition image segmentation object detection road vehicles traffic engineering computing heuristic approach license plate detection license plate recognition searching technique segmentation technique text locating-based technique

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Optimization Design and Implementation of Gateway Based on Firewall for Access Control 6

Optimization Design and Implementation of Gateway Based on F...

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6th International Conference on Information Science and Technology (ICIST)

作者： Zhu, YaChao Univ Elect Sci Technol China Res Inst Elect Sci & Technol Chengdu Peoples R China

ISBN: (纸本)9781509012244

Considering that the traditional gateway can't meet the requirements of the increasingly strict network security management, here we propose a design of security gateway based on firewall technology. We realize the real-time, dynamic and fine-grained control of the internal and external network of the gateway. This article introduces a method for gateway to be built, and it's based on the firewall in linux system. I use both the rule priority and heap sort method to optimize the efficiency of the gateway. It can be proved that the gateway based on heap sort and rule priority evaluation method can effectively reduce the time to solve the exception rule and improve the efficiency of abnormal rules.

关键词： firewall gateway netfilter firewall rule exception segmentation technique rule priority

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Generalized BI-RME Method Applied to the Analysis of Dielectric-Loaded Waveguide Components

Generalized BI-RME Method Applied to the Analysis of Dielect...

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IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO)

作者： Battistutta, Simone Bozzi, Maurizio Bressan, Marco Perregrini, Luca Univ Pavia Dept Elect Comp & Biomed Engn Pavia Italy

ISBN: (纸本)9781538652046

This paper presents the application of the generalized boundary integral-resonant mode expansion (BI-RME) method to the analysis of piecewise homogeneous waveguide components. The component is initially segmented into homogeneous building blocks, and for each block the generalized admittance matrix (GAM) is calculated in the typical BI-RME pole-expansion form. The terms of the pole-expansion are obtained by solving an integral equation obtained enforcing the perfect electric wall boundary condition to the electromagnetic field. Finally, by cascading the GAMs of the blocks the overall frequency response of the component is obtained. Thanks to the use of the RWG basis functions to represent the unknown electric and magnetic surface currents the method is particularly flexible. Its effectiveness is demonstrated through the analysis of two different components.

关键词： BI-RME method dielectric filters generalized admittance matrix segmentation technique arbitrary shaped building blocks

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