检索结果-南通市图书馆

Optimization of Fractal Iterated Function System(IFS) with Probability and Fractal Image Generation

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2001年第2期8卷 152-156页

作者： Berthe Kya, Yang Yang (Information engineering school, university of science and technology beijing, beijing 100083, china) Univ Sci & Technol beijing Informat Engn Sch Beijing 100083 Peoples R China

There are several methods for rendering fractal images based on IFS (Iterated Function System) in computer graphic; but one concern of the computer graphic community has been the efficiency rendering algorithms. The invariant measures arising from IFSP (Iterate Function System with Probability) using the probabilistic algorithm are also known as chaos games. The role of these probabilities to generate the image of the attractor has been investigated using a multi-fractal analysis. The conventional choice of probability associated with each set /S/ to generate the attractor in least time possible is introduced, then a new method based on the self similarity and multi-fractal analysis is presented. The efficiency of the new method has been proved over the conventional method.

关键词： optimization of fractal IFS compression IFSP multi-fractal analysis

Performance Modeling and Approximate Analysis of Multiserver Multiqueue Systems with Poisson and Self-similar Arrivals

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2001年第2期8卷 145-151页

作者： Zhiguang Shan, Chuang Lin, Yang Yang, Yan Wang (Information engineering school, university of science and technology beijing, beijing 100083, china) (Department of computer science and technology, Tsinghua university, beijing 100084, china) Univ Sci & Technol beijing Informat Engn Sch Beijing 100083 Peoples R China Tsinghua Univ Dept Comp Sci & Technol Beijing 100084 Peoples R China

The problem of state space explosion is still ran outstanding challenge in Markovian performance analysis for multiserver multiqueue (MSMQ) systems. The system behavior of a MSMQ system is described using stochastic high-level Petri net (SHLPN) models, and an approximate performance analysis technique is proposed based on decomposition and refinement methods as well as iteration technique. A real MSMQ system, Web-server cluster, is investigated. The performance of an integrated scheme of request dispatching and scheduling is analyzed with both Poisson and self-similar request arrivals. The study shows that the approximate analysis technique significantly reduces the complexity of the model solution and is also efficient for accuracy of numerical results.

关键词： multiserver multiqueue (MSMQ) system Web-server cluster performance analysis stochastic high-level Petri net (SHLPN) request dispatching request scheduling

Change Laws of Flake's Temperature during Making a Diamond Film by DC-PJ

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 97-102页

作者： Xuhong Chen Lihe Zhao Fanxiu Lu(Mechanical engineering school, university of science and technology beijing, beijing 100083, china) Mechanical engineering school University of Science and Technology Beijing Beijing 100083 China

When making a diamond film by direct current plasma jet, a kind piece of flake is used as a base body Which the film can beattached to. The flake's temperature is unstable. Therefore, some experiments and constructed mathematical models, which were solvedby computer, were done. The results show that the flake's temperature is influenced by many factors and the mains are plasma jet powerand vacuum pressure. Through adjusting the two parameters, the flake's temperature can be accurately controlled, furthermore, diamondfilms' quality would be improved. Lowering sediment platform's temperature has a little effect to the flake's temperature at present technology conditions.

关键词： CVD (Chemical Vapor Deposition) plasma, impact heat transfer

A new method for simulating human emotions

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2003年第2期10卷 72-74页

作者： Weimin Xue, Zhiliang Wang, Wenhong Xia, and Wenbo MengInformation engineering school, university of science and technology beijing, beijing 100083, china Information engineering school University of Science and Technology Beijing Beijing 100083 China

How to make machines express emotions would be instrumental in establishing acompletely new paradigm for man machine interaction. A new method for simulating and assessingartificial psychology has been developed for the research of the emotion robot. The human psychologyactivity is regarded as a Markov process. An emotion space and psychology model is constructedbased on Markov process. The conception of emotion entropy is presented to assess the artificialemotion complexity. The simulating results play up to human psychology activity. This model can alsobe applied to consumer-friendly human-computer interfaces, and interactive video etc.

关键词： emotion robot psychology entropy Markov model artificial psychology

Interactive graphics mechanical optimum design

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1997年第3期11卷 54-56页

作者： WANG Guobiao (Resources engineering school, university of science and technology beijing, beijing 100083, china)

Virtually all conventional optimizations are Performed in a batch computer environment. No graphic information during the optimization process is provided. The research tactics and implementation procedure of interactivegraphics in mechanical optimum design are presented. An interactive Graphics Mechanical Optimum Design Program(IGMODP) for microcomputers is developed. The example of wheeled loader' s working device optimum design usingIGMODP is carried out.

关键词： interactive graphics mechanical optimum design computer program

Secure communication by generalized chaotic synchronization

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2003年第2期10卷 75-78页

作者： Lequan Min, Xianhua Zhang, and Miao YangApplied science school, university of science and technology beijing, beijing 100083, china Applied science school University of Science and Technology Beijing Beijing 100083 China

Chaotic communication is a rather new and active field of research. Althoughit is expected to have promising advantages, some investigators provide evidences that chaoticcommunication is not safety. This letter provides a new chaotic secure communication scheme based ona generalized synchronization theory of coupled system. The secret message hidden in the chaoticsource signal generated via the scheme is very difficult to be unmasked by so-called nonlineardynamic forecasting technique. One example for Internet communications was presented to illustratethe security of our scheme.

关键词： secure communication generalized chaotic synchronization Internet

Synchronization of Digital Chaos in Secure Communication Systems

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2001年第4期8卷 299-305页

作者： Geng Zhao, Deling Zheng, ShaojunHuang 1)College of Electric science and technology beijing. beijing 100070, china 2)Information engineering school, university of science and technology beijing. beijing 100083, china Coll Elect Sci & Technol beijing Beijing 100070 Peoples R China Univ Sci & Technol beijing Informat Engn Sch Beijing 100083 Peoples R China

The theories of synchronization based on secure communications using digital chaos are presented. A new synchronous method-cycles-interval Pulse drive is developed and realized. Experimental results show it is available, and in order to reduce synchronous noise, a method using model references solves the ratio of signal power to noise power, so the secure communication system can be realized.

关键词： digital chaotic synchronization cycles-interval pulses drive synchronous noise model reference

Complex conforming Delaunay triangulation

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2010年第6期53卷 1130-1140页

作者： MENG XianHai 1, LI JiGang 1, YANG Qin 1, CAI Qiang 2 & CHEN QiMing 3 1 NLSDE, school of computer science and engineering, BeiHang university, beijing 100083, china 2.school of computer sciences, beijing technology and Business university, beijing 100037, china 3 school of Mechanical engineering and Automation, BeiHang university, beijing 100083, china 1. NLSDE School of Computer Science and Engineering BeiHang University Beijing 100083 China2. School of Computer Sciences Beijing Technology and Business University Beijing 100037 China3. School of Mechanical Engineering and Automation BeiHang University Beijing 100083 China

A novel algorithm of conforming Delaunay triangulation for curved geometry is presented in the paper.A progress has been made for the problem puzzled Delaunay refinement where curved constraints cannot be accepted as input *** algorithm is based on a new sufficient condition for the existence of constraints in *** requires computing only the intersection between constraints and Voronoi edges or faces instead of the circum-sphere of curved *** the termination of the algorithm when small input angles exist in constraints, a weighted method is applied to ensure that the algorithm can terminate under any *** two-dimensional and three-dimensional results are also *** is shown that the algorithm has the capability of dealing with both linear and nonlinear constraints in a consistent way, without the need of maintaining triangular meshes on face constraints.

关键词： mesh generation Delaunay triangulation conforming curved constraints tetrahedralization weight

Numerical simulation of strain localization and damage evolution in large plastic deformation using mixed finite element method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2004年第3期11卷 273-277页

作者： Zhanghua Chen Jiajian Jin Jiumei Xiao Applied science school, university of science and technology beijing, beijing 100083, china Applied science school University of Science and Technology Beijing Beijing 100083 China

An investigation of computer simulation is presented to analyze the effectsof strain localization and damage evolution in large plastic deformation. The simulation is carriedout by using an elastic-plastic-damage coupling finite element program that is developed based onthe concept of mixed interpolation of displacement/pressure. This program has been incorporated intoa damage mechanics model as well as the corresponding damage criterion. To illustrate theperformance of the proposed approach, a typical strain localization problem has been simulated. Theresults show that the proposed approach is of good capability to capture strain localization andpredict the damage evolution.

关键词： strain localization mixed element truesdell stress rate material damage