检索结果-南通市图书馆

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 Appl. Sci. Sch. Univ. of Sci. and Technol. 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

Genetic Algorithm for the Thermal Stresses Optimum Design ofFunctionally Gradient Material Plate

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3期13卷 224-227页

作者： Xiaodan Zhang Zhengbin Tang Changchun Ge(Applied Science school, university of Science and technology beijing, beijing 100083, china) Applied Science school University of Science and Technology Beijing Beijing 100083 China

Based on the thermal stress distribution for functionally gradient material (FGM) plates, a Genetic Algorithm (GA) method for the thermal stresses optimum design of FGM plate with computer technologies is given. The m... 详细信息

关键词： functionally gradient material (FGM) thermal stress Genetic Algorithm (GA) crossover mutation

Algorithm of simulation time synchronization over large-scale nodes

在线全文

学校读者我要写书评

暂无评论

Science in china(Series F) 2008年第9期51卷 1239-1255页

作者： ZHAO QinPing1,2,ZHOU Zhong1,2 & Lü Fang1,2 1 State Key Laboratory of Virtual Reality technology and Systems,Beihang university,beijing 100083,china 2 school of computer Science and Engineering,Beihang university,beijing 100083,china State Key Laboratory of Virtual Reality technology and Systems Beihang University Beijing China school of computer Science and Engineering Beihang University Beijing China

In distributed simulation, there is no uniform physical clock. And delay cannot be estimated because of jitter. So simulation time synchronization is essential for the event consistency among nodes. This paper investigates time synchronization algorithms over large-scale distributed nodes, analyzes LBTS （lower bound time stamp） computation model described in IEEE HLA standard, and then presents a grouped LBTS model. In fact, there is a default premise for existing algorithms that controi packets must be delivered via reliable transportation. Although, a theorem of time synchronization message＇s reliability is proposed, which proves that only those control messages that constrain time advance need reliability. It breaks out the default premise for reliability. Then multicast is introduced into the transmis- sion of control messages, and algorithm MCTS （multi-node coordination time synchronization） is proposed based on multicast. MCTS not only promotes the time advance efficiency, but also reduces the occupied network bandwidth. Experiment results demonstrate that the algorithm is better than others in both time advance speed and occupied network bandwidth. Its time advance speed is about 50 times per second when there are 1000 nodes, approximately equal to that of similar systems when there are 100 nodes.

关键词： distributed simulation time synchronization multi-node coordination LBTS multicast

One-Dimensional Fractal Curves and Fractal Dimension Determination

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 165-168页

作者： Qikai Li Yue Zhang Wuyang Chu(Applied Science school, university of Science and technology beijing, beijing 100083, china) Applied Science school University of Science and Technology Beijing Beijing 100083 China

Various methods for evaluating the fractal curves were reviewed and simulated on computer. It is shown box-counting and power spectrum methods generally give poor measuring results, while yard and variation methods could obtain good results. However,owing to multiple influencing factors, further study needs to be done before widespread application of variation method. In order to improve the measuring accuracy of yard method, a new method has been propoed to measure the fractal dimension by changing the instrumental resolutions.

关键词： fractal fractal dimension computer simulation

Temperature-controlled ionic liquid dispersive liquid phase microextraction combined with ultra-high-pressure liquid chromatography for the rapid determination of triclosan,triclocarban and methyl-triclosan in aqueous samples

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2010年第12期53卷 2600-2607页

作者： GUO JieHong 1,2,LI XingHong 2,CAO XueLi 1,QU Lei 2,3,HOU DeKun 2 & XU XiaoBai 2 1 school of Chemical and Environmental Engineering,beijing technology and business university,beijing 100048,china 2 State Key Laboratory of Environmental Chemistry and Eco-toxicology Research Center of Eco-Environmental sciences,Chinese Academy of sciences,beijing 100085,china 3 Zhengzhou university,Zhengzhou 450001,china school of Chemical and Environmental Engineering Beijing Technology and Business University Beijing China State Key Laboratory of Environmental Chemistry and Eco-toxicology Research Center of Eco-Environmental sciences Chinese Academy of Sciences Beijing China Zhengzhou university Zhengzhou China

As extraction solvents,ionic liquids have green *** this study,an environmentally benign analytical method termed temperature-controlled ionic liquid dispersive liquid phase microextraction (TIL-DLME) combined with ultra-highpressure liquid chromatography (UHPLC)-tunable ultraviolet detection (TUV) was developed for the pre-concentration and determination of triclosan (TCS),triclocarban (TCC) and methyl-triclosan (M-TCS) in water *** parameters that may affect extraction efficiencies were examined and optimized,including the types and amount of ionic liquids,volume of the diluent,heating temperature,cooling time,salt effect and pH *** the optimum conditions,linearity of the method was observed in the ranges of 0.0100-100 μgL-1 for TCS and M-TCS,and 0.00500-50.0 μgL-1 for TCC with correlation coefficients (r2) > *** limits of detection (LODs) ranged from 1.15 to 5.33 *** in domestic water and TCC in reclaimed water were detected at the concentrations of 1.01 and 0.126 μgL-1,*** spiked recoveries of the three target compounds in reclaimed water,irrigating water,waste water and domestic water samples were obtained in the ranges of 68.4%-71.9%,61.6%-87.8%,58.9%-74.9% and 64.9%-92.4%,*** with the previous dispersive liquid-liquid microextraction method (DLLME) about the determination of TCS,TCC and M-TCS,this method is not only more environmentally friendly but also more sensitive.

关键词： ionic liquid temperature-controlled ionic liquid dispersive liquid phase microextraction UHPLC aqueous samples

Information content security on the Internet:the control model and its evaluation

在线全文

学校读者我要写书评

暂无评论

Science china(Information sciences) 2010年第1期53卷 30-49页

作者： FANG BinXing1, GUO YunChuan2,3 & ZHOU Yuan4 1school of computer, beijing university of Posts and Telecommunications, beijing 100029, china 2Institute of Computing technology, Chinese Academy of sciences, beijing 100190, china 3Graduate university of Chinese Academy of sciences, beijing 100049, china 4National computer Network Emergency Response Technical Team/Coordination Center of china, beijing 100029, china school of computer Beijing University of Posts and Telecommunications Beijing China Institute of Computing technology Chinese Academy of Sciences Beijing China Graduate university of Chinese Academy of sciences Beijing China National computer Network Emergency Response Technical Team/Coordination Center of china Beijing China

Flooding of harmful information on the Internet seriously endangers the physiological and mental health of teenagers. Due to the user-friendliness of the Internet as well as the difficulty in the authentication for the access of specific categories of information, curbing the transmission of harmful information, i.e., assuring the information content security (ICS), has become a reasonable yet challenging alternative. At present, there is an urgent need to develop a systematic model that can effectively carry out the curbing. In fact, curbing the transmission of harmful information by way of filtering can be modeled by access control. In the paper, based on the three core-elements of communication, namely, "Who communicates with whom", "How do they communicate" and "What is the content of communication", we propose a control model, called ICCON. Unlike the existing access control, the reference monitor (RM) of our model is placed in the transmission channel, and moreover, an evaluation frame is proposed, through which the effectiveness of the RM in controlling information transmission on the Internet can be quantitatively evaluated.

关键词： content security access control quantitative evaluation

Adaptive neural control based on HGO for hypersonic flight vehicles

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Information sciences) 2011年第3期54卷 511-520页

作者： XU Bin 1,2 , GAO DaoXiang 3 & WANG ShiXing 1 1 Department of computer Science and technology, Tsinghua university, beijing 100084, china 2 Autonomous System Lab, ETH Zurich Zurich 8092, Switzerland 3 school of technology, beijing Forestry university, beijing 100083, china Department of computer Science and technology Tsinghua University Beijing China Autonomous System Lab ETH Zurich Zurich Switzerland school of technology Beijing Forestry University Beijing China

This paper describes the design of adaptive neural controller for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV) which are decomposed into two functional systems, namely the altitude subsystem and the velocity subsystem. For each subsystem, one adaptive neural controller is investigated based on the normal output-feedback formulation. For the altitude subsystem, the high gain observer (HGO) is taken to estimate the unknown newly defined states. Only one neural network (NN) is employed to approximate the lumped uncertain system nonlinearity during the controller design which is considerably simpler than the ones based on back-stepping scheme with the strict-feedback form. The Lyapunov stability of the NN weights and filtered tracking error are guaranteed in the semiglobal sense. Numerical simulation study of step response demonstrates the effectiveness of the proposed strategy in spite of system uncertainty.

关键词： adaptive neural control hypersonic flight vehicle high gain observer output-feedback

A new method for simulating human emotions

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 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 Info. Eng. Sch. Univ. of Sci. and Technol. 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

Radiance-based color calibration for image-based modeling with multiple cameras

在线全文

学校读者我要写书评

暂无评论

Science china(Information sciences) 2012年第7期55卷 1509-1519页

作者： ZHAO Xu 1,2 ,ZHOU Zhong 1,2 & WU Wei 1,2 1 State Key Laboratory of Virtual Reality technology and Systems,Beihang university,beijing 100191,china 2 school of computer Science and Engineering,Beihang university,beijing 100191,china State Key Laboratory of Virtual Reality technology and Systems Beihang University Beijing China school of computer Science and Engineering Beihang University Beijing China

Photo-consistency estimation is an important part for many image-based modeling *** paper presents a novel radiance-based color calibration method to reduce the uncertainty of photo-consistency estimation across multiple *** idea behind our method is to convert colors into a uniform radiometric color space in which multiple image data are *** results demonstrate that our method can achieve comparable color calibration effect without adjusting camera parameters and is more robust than other existing ***,we obtain an auto-determined threshold for photo-consistency check,which will lead to a better performance than existing photo-consistency based reconstruction algorithms.

关键词： color calibration photo-consistency estimation multi-camera system image-based modeling