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Research on a Fast-Closing Switch Based Fault Current Limiter with Series Compensation

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Journal of Donghua univ.rsity(eng.ish Edition) 2002年第3期19卷 23-27页

作者：陈金祥邹积岩董恩源石晶 dept. of Elec. eng. Huazhong Univ. of Sci. and Technol. Wuhan 430070 China dept. of Elec. and Electron. eng. Dalian Univ. of Technol. Dalian 116023 China

A new type of fault current limiter (FCL) with series compensation based fast-closing switch is proposed. It is composed of a capacitor bank and a reactor in series. The main control component is a fast-closing switch connected in parallel with the capacitors, which is driven by the electromagnetic repulsion force. When fault occurs, the switch closes and bypasses the capacitors, and the fault is limited by the reactor then. Simulated analysis and experiments show that it is feasible to develop the FCL with low cost and high reliability. The effectiveness of transient stability for power system is evaluated by digital simulation.

关键词： fault current limiter(FCL), series compensation,fast-closing switch, system stability.

Algorithm of graph isomorphism with threedimensional DNA graph structures

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Progress in Natural science:Materials International 2005年第2期15卷 86-89页

作者： LIU Guangwu 1,2*, YIN Zhixiang 1,3, XU Jin1 and DONG Yafei1(1. Department of control science and eng.neering, Hua Zhong univ.rsity of science and Technology, Wuhan 430074, China 2. College of Transportation, Wuhan univ.rsity of Technology, Wuhan 430063, China 3. Department of Mathematics and Physics, Anhui univ.rsity of science and Technology, Huainan 232001, China) dept. of control science and eng. Huazhong Univ. of Sci. and Technol. Wuhan 430074 China Coll. of Transportation Wuhan Univ. of Technology Wuhan 430063 China dept. of Mathematics and Physics Anhui Univ. of Sci. and Technol. Huainan 232001 China

An algorithm for solving the graph isomorphism problem with 3-D DNA structures is proposed in this paper. The k-armed branched junction molecules are used to code k-degree vertices. Double stranded molecules are used to code edges. Then the molecules are mixed in a tube to be ligated. The result can be detected by gel electrophoresis. The time complexity of the algorithm is O(n2), where n is the number of vertices of the graph.

关键词： DNA computing DNA graph structure graph isomorphism

THE MOLECULAR ALGORITHM OF CONNECTIVITY BASED ON THREE DIMENSIONAL DNA STRUCTURE

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Journal of Electronics(China) 2007年第1期24卷 104-107页

作者： Fang Gang Zhang Shemin Zheng.Anping Xu Jin dept.of control science and eng. Huazhong Univ. of Sci. and Tech. Wuhan 430074 China Informatics and control eng. dept Zhengzhou Univ. of Light Industry Zhengzhou 450002 China

Inspired by the potential computational capability of 3-Dimensional (3D) DNA structure,this paper presents a graph structure constructed by k-armed (k = 3or 4) branched junction DNA molecules to explore the possibility of solving some intractable problems. In the proposed procedure,vertex building blocks consisting of 3,4-armed branched junction molecules are selectively used to form different graph structures. After separating these graph structures by gel electrophoresis,the connec-tivity of this graph can be determined. Furthermore,the amount of potential solutions can be reduced by a theorem of graph theory.

关键词： 3-Dimensional (3D) DNA structure Connectivity DNA computing

LOW COMPLEXITY LMMSE TURBO EQUALIZATION FOR COMBINED ERROR control CODED AND LINEARLY PRECODED OFDM

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Journal of Electronics(China) 2006年第1期23卷 1-6页

作者： Qu Daiming Zhu Guangxi dept.of Electro. ＆ lnfo. eng. Huazhong University of Sci. ＆ Tech. Wuhan 430074 China

The turbo equalization approach is studied for Orthogonal Frequency Division Multiplexing （OFDM） system with combined error control coding and linear precoding. While previous literatures employed linear precodcr of small size for complexity reasons, this paper proposes to use a linear precoder of size larger than or equal to the maximum leng.h of the equivalent discrete-time channel in order to achieve full frequency diversity and reduce complexities of the error control coder/decoder. Also a low complexity Linear Minimum Mean Square Error （LMMSE） turbo equalizer is derived for the receiver. Through simulation and performance analysis, it is shown that the performance of the proposed scheme over frequency selective fading channel reaches the matched filter bound; compared with the same coded OFDM without linear precoding, the proposed scheme shows an Signal-to-Noise Ratio （SNR） improvement of at least 6dB at a bit error rate of 10 6 over a multipath channel with exponential power delay profile. Convergence behavior of the proposed scheme with turbo equalization using various type of linear precoder/transformer, various interleaver size and error control coder of various constraint leng.h is also investigated.

关键词： Orthogonal Frequency Division Multiplexing (OFDM) Linear precoding Turbo equalization Linear Minimum Mean Square Error (LMMSE)

A STUDY ON PROBE-BASED MULTICAST ADMISSION control AND ENHANCEMENT

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Journal of Electronics(China) 2006年第1期23卷 69-75页

作者： Le Chunhui He Jianhua Yang Zongkai Liu Wei dept.of Electronics and Info. eng. Huazhong University. of Sci.and Tech. Wuhan 430074 China

To provide scalable and simple Quality of Service（QoS） mechanism for multicast services, Probe-Based Multicast Admission control （PBMAC） scheme was proposed. In this paper, PBMAC is studicd and a so-called subsequent request problem is found in PBMAC, which degrades system performance significantly when the network traffic is heavily loaded. Based on the analysis on subsequent request problem, an Enhance PBMAC （EPBMAC） scheme is proposed, in which complementary probing is devised to solve the problem. Using a new metric of normalized requested equivalent link capacity, the pertbrmance of PBMAC and EPBMAC is analyzed and evaluated. Two implementations are proposed for incremental dcployment. The paper finally introduces evaluation with packet-based simulations. Both analytical and simulation results show the significant improvement in performance.

关键词： Multicast Quality of Service (QoS) Admission control Traffic probing