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Large-scale P2.VOD system:Focusing on clients

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science china(Information sciences) 2011年第8期54卷 1677-1690页

作者： HUANG Yan 1,XU Ke 2.LI HaiTao 2., CAO Yang 1 & YAO Xin 1 1 shanghai SynaCast Media Tech Co.,Ltd,shanghai 2.12.4,{2. 2.department of computer science & technology,Tsinghua University,Beijing 100084,{2. 1. shanghai SynaCast Media Tech Co. Ltd Shanghai 201204 China2. Department of Computer Science & Technology Tsinghua University Beijing 100084 China

Using P2. network to provide video on demand (VOD) service can support large-scale users so as to save the bandwidth cost of *** VOD must support VCR characters (drag,pause,randomly choosing watching position,etc.),building a large-scale expansion of high-performance VOD system still faces huge *** paper first presents a P2. based reference model,defines the design object,and analyzes the *** then taking PPLive demand system as an example,it gives client-based solutions,including disk cache-out strategy,memory cache prefetch strategy,maintaining relations between neighbors,task scheduling,data upload strategies and so ***-demand systems are putting into practice at present with satisfactory fluency and drag *** largest number of simultaneous online users is over 2.0000,and online video data is over 700. Compared with traditional client-server model,the average bandwidth saving rate of servers is 88% or more,and the bandwidth saving rate of user-number's the peak value can be up to 93%.

关键词： P2. VOD server bandwidth saving rate fluency drag delay

WATER TUNNEL EXPERIMENTAL INVESTIGATION ON THE DRAG REDUCTION CHARACTERISTICS OF THE TRAVELING WAVY WALL

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Journal of Hydrodynamics 2011年第1期23卷 65-70页

作者： YAO Yan LU Chuan-jing SI Ting ZHU Kun department of engineering Mechanics Shanghai Jiao Tong University Shanghai 200240 China Beijing Electromechanic engineering Institute Beijing 100074 China State Key Laboratory of Ocean engineering Shanghai Jiao Tong University Shanghai 200030 China department of modem Mechanics University of Science and Technology of China Hefei 230027 China

Drag reduction experiment of the traveling wavy wall at high Reynolds number is conducted.A suit of traveling wavy wall device is *** drag forces of the traveling wavy wall with various wave speeds（c）are measured under different water speeds（U）in the K15 cavitation water tunnel and are compared with that of the flat *** results show that the mean drag force of the traveling wavy wall have decreased and then increased with oscillation frequency increasing at the same flow *** different flow speeds,when traveling wave wall reached to the minimum of drag force,the corresponding the ratio of the wall motion phase speed c to flow speed U,c /U is slightly *** the parameters of the experiment,whenc /U reaches a certain value,the drag force of the traveling wavy wall can be less than that of the flat *** drag reduction can be up to 42..Furthermore,as the value ofc /U increases,the traveling wavy wall can restrain the separation and improve the quality of flow field.

关键词： flow control drag reduction traveling wavy wall water tunnel test

An Automatic Testing System of Scheduling Strategies in Real-Time UNIX

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Journal of Systems engineering and Electronics 2001年第2期12卷 59-62页

作者： Qin Xiao, Pang Liping & Han Zongfen department of computer {2., Huazhong University of {2. and technology, Wuhan 430074, P. R. china department of computer {2. Huazhong University of Science and Technology Wuhan 430074 P. R. China

This paper proposes a formal model of the automatic testing system for scheduling strategies in real-time UNIX and describes the algorithm of the key part of the system. The model of the system is an important technology of the automatization of software development. According to the model presented in the paper, many different kinds of automatic testing systems can be designed and developed easily. At the end of the paper, the prototype proves the feasibility of the model and design.

关键词： Algorithms Automatic testing Real time systems Scheduling Software prototyping

A Heuristic Algorithm for QoS Multicast Routing

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Journal of Systems engineering and Electronics 2002年第4期13卷 73-78页

作者： Li Layuan & Li Chunlin department of computer {2., Wuhan University of technology, Wuhan 430063, P. R. china department of computer {2. Wuhan University of Technology Wuhan 430063 P. R. China

In recent years, QoS multicast routing has continued to be a very important research topic in the areas of networks. This paper presents a heuristic algorithm for the QoS multicast routing (HAQMR). This heuristic algorithm deals with delay and bandwidth constraints and has low cost. The HAQMR attempts to significantly reduce the overhead for constructing a multicast tree, the proof for correctness of the HAQMR is given, and the performance of the HAQMR is evaluated by simulations. The study shows that HAQMR provides an available approach to QoS multicast routing.

关键词： Heuristic QoS Multicast QoS constraints QoS routing.

Data classification from the inverse nth power gravitation

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science china(Information sciences) 2012年第1期55卷 184-190页

作者： XU HuaRong1,WANG XiaoDong1,ZENG ZhiQiang1&FANG Qiu2.1department of computer {2. and technology,Xiamen University of technology,Xiamen 36102.,china 2.0} of Mechanical engineering,Xiamen University of technology,Xiamen 36102.,china 1. department of computer {2. and technology Xiamen University of Technology Xiamen 361024 China2. Department of Mechanical Engineering Xiamen University of Technology Xiamen 361024 China

By the inverse nth power gravitation in physics,a novel classifier for data classification,called the I-n-PG classifier,is *** the I-n-PG model,training samples from each class are regarded as a system of particles and an I-n-PG field is defined for each class.A test sample belongs to the class whose particle system has the maximum I-n-PG to this test *** on large numbers of real data show that the I-n-PG classifier can provide a good classification *** with the nearest neighbor classifier and SVM,performances of the I-n-PG classifier are always superior/close to the better one of them,and thus the I-n-PG classifier has also a wide range of adaptability to data sets.

关键词： data classification inverse nth power gravitation

Canonical Huffman code based full-text index

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Progress in Natural science:Materials International 2008年第3期18卷 325-330页

作者： Yi Zhang a,b, Zhili Pei a, Jinhui Yanga, Yanchun Liang a, a College of computer science and {2., Jilin University, Key Laboratory of Symbol Computation and Knowledge engineering of the Ministry of Education, Changchun 130012. china b department of computer science, Jilin {2. and Business College, Changchun 130062. china College of computer science and {2. Jilin University Key Laboratory of Symbol Computation and Knowledge Engineering of the Ministry of Education Changchun 130012 China department of computer {2. Jilin Technology and Business College Changchun 130062 China

Full-text indices are data structures that can be used to find any substring of a given string. Many full-text indices require space larger than the original string. In this paper, we introduce the canonical Huffman code to the wavelet tree of a string T[1. . .n]. Compared with Huffman code based wavelet tree, the memory space used to represent the shape of wavelet tree is not needed. In case of large alphabet, this part of memory is not negligible. The operations of wavelet tree are also simpler and more efficient due to the canonical Huffman code. Based on the resulting structure, the multi-key rank and select functions can be performed using at most nH0 + jRj(lglgn + lgn lgjRj)+O(nH0) bits and in O(H0) time for average cases, where H0 is the zeroth order empirical entropy of T. In the end, we present an efficient construction algorithm for this index, which is on-line and linear.

关键词： Full-text index Su?x automaton Canonical Hu?man code

Solving A Kind of High Complexity Multi-Objective Problems by A Fast Algorithm

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Wuhan University Journal of Natural sciences 2003年第S1期8卷 183-188页

作者： Zeng San-you, Ding Li-xin, Kang Li-shandepartment of computer {2.,china University of Geo{2.s, Wuhan 430074, Hubei, china department of computer {2., Zhuzhou Institute of technology , Zhuzhou 412.08, Hunan, china State Key Laboratory of Software engineering, Wuhan University, Wuhan 430072. Hubei, china china University of Geosciences Department of Computer Science Wuhan Hubei China (GRID:grid.162107.3) (ISNI:***) Zhuzhou Institute of technology Department of Computer Science Zhuzhou Hunan China (GRID:grid.162107.3) china University of Geosciences Department of Computer Science Wuhan Hubei China (GRID:grid.162107.3) (ISNI:***) Wuhan University State Key Laboratory of Software Engineering Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

A fast algorithm is proposed to solve a kind of high complexity multi-objective problems in this paper. It takes advantages of both the orthogonal design method to search evenly, and the statistical optimal method to speed up the computation. It is very suitable for solving high complexity problems, and quickly yields solutions which converge to the Pareto-optimal set with high precision and uniform distribution. Some complicated multi-objective problems are solved by the algorithm and the results show that the algorithm is not only fast but also superior to other MOGAS and MOEAs, such as the currently efficient algorithm SPEA, in terms of the precision, quantity and distribution of solutions.

关键词： evolutionary algorithms orthogonal design multi-objective optimization Pareto-optimal set

Search　Algorithm　for　Determining　the　Range　of　the　Possible　Collision　of　Conver　Polygons

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Journal of Systems engineering and Electronics 1996年第3期7卷 31-42页

作者： Li Qinghua(department of computer {2. and engineeringHuazhong University of {2. technology, Wuhan, 430074, P. R. china) department of computer {2. and engineering Huazhong University of {2. technology Wuhan 430074 P. R. China

Let P=(po, p1,..., pn-1 ) and Q=(qo,q1..., qm-1) be two arbitrary convex polygonsin plane. In this paper, the author studies the problems of how to quickly determine their possiblecollision range and movable range. In the paper, a new sufficient and necessary condition for decidingpossible collision is proposed,and the basic characters of the oblique supporting lines are investigated,and on these grounds the problem to determine the possible collision range is transformed into thatof searching the supporting points on the sets of convex polygon vertexs. Using the strategy ofsearching simultaneously the sets of vertexes of P and Q, the author constructs the fast algorithmfor finding the supporting points, the time-complexity of which is O(log2.m + n)). Based on theseresults, the algorithms to quickly determine the range are given, which possess the time-complexityof O(log2.m+n)).

关键词： Possible collision Ranges of possible and impossible collision Oblique supporting line,Supporting points.

EXPERIMENTAL INVESTIGATION ON THE DRAG REDUCTION CHARACTERISTICS OF TRAVELING WAVY WALL AT HIGH REYNOLDS NUMBER IN WIND TUNNEL

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Journal of Hydrodynamics 2010年第5期22卷 719-724页

作者： YAO Yan LU Chuan-jing SI Ting ZHU Kun department of engineering Mechanics Shanghai Jiao Tong University Shanghai 200240 China Beijing Electromechanic engineering Institute Beijing 100074 China State Key Laboratory of Ocean engineering Shanghai Jiao Tong University Shanghai 200030 China department of Modern Mechanics University of Science and Technology of China Hefei 230027 China

Drag reduction experiments of the traveling wavy wall at high Reynolds number, ranging from 1.46×106 to 5.83×106 based on the free-stream velocity and the model length, were conducted. A suit of traveling wavy wall device was developed and its characteristics of drag reduction at high Reynolds number were investigated. The drag forces of the traveling wavy wall with various wave speeds （ c ） were measured at different wind speeds （U ） in the FL-8 low-speed wind tunnel and compared with the drag force of the flat plate. The results show that the mean drag force of the traveling wavy wall decreases as the value of c /U increases, at different wind velocities, the values of c /U corresponding to minimal drag force of the traveling wavy wall are different, when the values of c /U are larger than 0.6, the mean drag forces of the traveling wavy wall are smaller than those of the flat plate, and the drag reduction can be up to 60%. The drag reduction effectiveness of traveling wavy wall is thus achieved. Furthermore, as the value of c /U increases, the traveling wavy wall can restrain the separation and improve the quality of flow field.

关键词： flow control drag reduction traveling wavy wall wind tunnel test