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A MESSAGE-DRIVING FORMALISM FOR MODELING AND SIMULATION OF MULTI-AGENT SUPPLY CHAIN SYSTEMS

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Journal of Systems Science and Systems Engineering 2011年第4期20卷 385-399页

作者： Wenzhe TAN1 Yueting CHAI2 yi LIU3 1department of Automation, tsinghua university, beijing, 100084, china 2department of Automation, tsinghua university, beijing, 100084, china 3department of Automation, tsinghua university, beijing, 100084, china department of Automation Tsinghua University Beijing China

To acquire a competitive advantage in the expanding market, manufacturing enterprises should be able to manage their supply chains as effectively as possible. It is now becoming popular to model supply chains as multi-agent systems and use discrete event simulation to learn more about their behaviors or investigate the implications of alternative configurations. In order to enhance the computational efficiency and keep the simulation credibility, this paper proposes a message-driving formalism for the simulation of multi-agent supply chain systems. Through the message-driving formalism, the problem of shared variables is addressed and the parallel operation of agents is implemented. Simulation experiments with a prototype implementation show that the message-driving formalism is able to provide credible results in significantly less simulation time.

关键词： Supply chain multi-agent system modeling and simulation parallel discrete event simulation message-driving formalism

SYNTHESIS OF NOVEL SOLUBLE AROMATIC POLYPYROMELLITIMIDE CONTAINING ORDERED 1,2,4-TRIAZINE IN THE MAIN CHAIN

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Chinese Journal of Polymer Science 2002年第3期20卷 219-224页

作者： Xiao-bing yi Guo-shi Wu Feng-cai Lu department of Chemistry tsinghua university, beijing 100084 china Institute of Chemistry Chinese Academy of sciences, beijing 100080, china Tsing Hua Univ Dept Chem Beijing 100084 Peoples R China Chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

A new heat-resistant, soluble polymer, poly(phenyl-1,2,4-triazine imide), has been prepared via a two-step method of polycondensation of N,N'-bis(4-benzil)pyromellitimide and terephthalamidrazone in cresol, followed by curing at higher temperature. The rigid 1,2,4-triazine group increases the solubility of the polyimide so that the polymer is soluble in cresol, N-methyl-2-pyrrolidone (NMP), trifluoroacetic acid and concentrated sulfuric acid, etc. Thermogravimetric analysis (TGA) indicates that this novel polyimide has good thermal stability with a high decomposition temperature of 447degreesC in air and of 423 degreesC in N-2, It has a tensile strength of 107.4 MI'a with an elongation at break of around 7.6%.

关键词： polyimides N,N '-bis(4-benzil)pyromellitimide rigid-rod group 1,2,4-triazine

MINIMIZING A LINEAR FRACTIONAL FUNCTION SUBJECT TO A SYSTEM OF SUP-T EQUATIONS WITH A CONTINUOUS ARCHIMEDEAN TRIANGULAR NORM

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Journal of Systems Science & Complexity 2009年第1期22卷 49-62页

作者： Pingke LI Edward P.Fitts department of Industrial and Systems Engineering,North Carolina State university,Raleigh,NC 27695-7906,US Shu-Cherng fang Edward P.Fitts department of Industrial and Systems Engineering,North Carolina State university,Raleigh,NC 27695-7906,USA department of mathematical sciences,tsinghua university,beijing 100084,china College of Management,Dalian university of Technology,Dalian 116024,china. department of Industrial and Systems Engineering North Carolina State University

This paper shows that the problem of minimizing a linear fractional function subject to asystem of sup-T equations with a continuous Archimedean triangular norm T can be reduced to a 0-1linear fractional optimization problem in polynomial ***,parametrization techniques,e.g.,Dinkelbach's algorithm,can be applied by solving a classical set covering problem in each *** reduction can also be performed on the sup-T equation constrained optimization problems withan objective function being monotone in each variable *** method could be extended aswell to the case in which the triangular norm is non-Archimedean.

关键词： Fractional optimization fuzzy relational equations triangular norms.

Assembly and structure of protein phosphatase 2A

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Science china(Life sciences) 2009年第2期52卷 135-146页

作者： SHI yi Gong Center for Structural Biology, department of Biological sciences and Biotechnology, and School of Medicine, tsinghua university, beijing 100084, china 1. Center for Structural Biology Department of Biological Sciences and Biotechnology and School of Medicine Tsinghua University Beijing 100084 China

Protein phosphatase 2A (PP2A) represents a conserved family of important protein serine/threonine phosphatases in species ranging from yeast to human. The PP2A core enzyme comprises a scaffold subunit and a catalytic subunit. The heterotrimeric PP2A holoenzyme consists of the core enzyme and a variable regulatory subunit. The catalytic subunit of PP2A is subject to reversible methylation, medi-ated by two conserved enzymes. Both the PP2A core and holoenzymes are regulated through interac-tion with a large number of cellular cofactors. Recent biochemical and structural investigation reveals critical insights into the assembly and function of the PP2A core enzyme as well as two families of holoenzyme. This review focuses on the molecular mechanisms revealed by these latest advances.

关键词： protein phosphorylation dephosphorylation PP2A structure mechanism

FL-FN-MOGA Based Traffic Signal Control

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Journal of Systems Engineering and Electronics 2003年第3期14卷 14-23页

作者： Wei Wu & Zhang yi department of Automation, tsinghua university, beijing 100084, P. R. china department of Automation Tsinghua University Beijing 100084 P. R. China

In this paper, a traffic signal control method based on fuzzy logic (FL), fuzzy-neuro (FN) and multi-objective genetic algorithms (MOGA) for an isolated four-approach intersection with through and left-turning movements is presented. This method has an adaptive signal timing ability, and can make adjustments to signal timing in response to observed *** 'urgency degree' term, which can describe the different user's demand for green time is used in decision-making by which strategy of signal timing can be determined. Using a fuzzy logic controller, we can determine whether to extend or terminate the current signal phase and select the sequences of phases. In this paper, a method based on fuzzy-neuro can be used to predict traffic parameters used in fuzzy logic controller. The feasibility of using a multi-objective genetic algorithm ( MOGA) to find a group of optimizing sets of parameters for fuzzy logic controller depending on different objects is also demonstrated. Simulation results show that the proposed methed is effecfive to adjust the signal timing in response to changing traffic conditions on a real-time basis, and the controller can produce lower vehicle delays and percentage of stopped vehicles than a traffic-actuated controller.

关键词： Traffic signal control Fuzzy logic Fuzzy-neuro Multi-objective genetic algorithms.

To enhance the reproduction of Phanerochaete chrysosporium by adding natural lixiviums in liquid medium

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Journal of Environmental sciences 2003年第6期15卷 808-814页

作者： LIN Gang, WEN Xiang-hua, QIAN yi (department of Environmental Science and Engineering, tsinghua university, beijing 100084, china. department of Environmental Science and Engineering Tsinghua University Beijing 100084 Chin

Great promotion to the reproduction of white rot fungus Phanerochaete chrysosporium by adding natural lixiviums such as from wood, maize core and potato in liquid medium was found in this research. Incubated in the liquid medium contained 10 mg/L glucose as carbon source with natural lixiviums for three days, the production of mycelium pellet reaches more than 80 g/L, which is 5 times more than that of without natural lixiviums. Incubated in the liquid medium contained 5 mg/L glucose as carbon source with natural lixiviums for three days, the production of mycelium pellet can reach 69.5 g/L, while the production in the medium without natural lixiviums is very low. When the liquid medium contained 1—20 g/L glucose as carbon source, the production of mycelium pellet in 3 d can only reach 12.5 g/L to 14.5 g/L. The fungus in the medium with potato lixiviums are easily contaminated by other microorganisms and in the medium with maize core lixiviums are easily bulking, while in the medium with wood lixiviums are neither easily contaminated nor bulking. Medium with wood lixiviums can produce more pellet than other medium, endure contamination and keep better sedimentation capacity. So that, wood lixivium is better additive to the culture of white rot fungi in liquid medium. Addition of the mixture of wood, maize core and potato lixiviums is of advantage to the production of mycelium pellet. The difference of the production in the medium with different amount of wood lixiviums showed little in the first 3 d, while it expanded after 3 d. Wood lixiviums stimulate the growth of P. chrysosporium instead of supply organics which fungi need.

关键词： white rot fungi medium additive

Entropy number and non-linear approximations on multivariate Besov space by manifolds of finite pseudo-dimension

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Progress in Natural Science:Materials International 2006年第3期16卷 260-265页

作者： LONG Jingfan and fang Gensun (School of mathematical sciences, beijing Normal university, beijing 100875, china.department of Computer Science, Information Technology Institute, beijing 100101, china) [a]School of mathematical sciences Beijing Normal University Beijing China [b]department of Computer Science Information Technology Institute Beijing China

We determine the asymptotic order of entropy number and optimal non -linear approximations of anisotropic periodic Besov class of Bpθr(Td') (1≤p≤∞,1≤0≤∞) by manifolds of finite pseudo-dimension in the metric Lq... 详细信息

关键词： Pseudo-dimension anisotropic Besov class of functions entropy number nonlinear width.

RESEARCH OF MICRO ELECTRO DISCHARGE MACHINING EQUIPMENT AND PROCESS TECHNIQUES

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Chinese Journal of Mechanical Engineering 2002年第2期15卷 177-181页

作者： Li Yong Guo Min Li fang Zhou Zhaoying department of Precision Instruments and Mechanology, tsinghua university, beijing 100084, china department of Precision Instruments and Mechanology Tsinghua University 北京 100084

Micro electro discharge machining (micro EDM) is a feasible way tomanufacture micro structures and has potential application in advanced industrial fields. For therealization of micro EDM, it is necessary to pay careful attention to its equipment design and thedevelopment of process techniques. The present status of research and development of micro EDMequipment and process techniques is overviewed. A micro electro discharge machine incorporated withan inchworm type of micro feed mechanism is introduced, and a micro electro discharge machine fordrilling micro holes suitable to industrial use is also introduced. Some of the machiningexperiments carried out on the micro EDM prototypes are shown and the feasibility of the micro EDMtechnology to practical use is discussed.

关键词： Micro electro discharge machining Inchworm mechanism Friction drivemechanism Micro electrode Micro hole Micro structure

A Study on Numerical Simulation of Core-Shooting Process

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Journal of Materials Science & Technology 2001年第6期17卷 625-628页

作者： Junjiao WU, yi GUI and Wenzhen LI department of Mechanical Engineering, tsinghua university, beijing 100084, china [Manuscript received July 18, 2000, in revised form August 25, 2000] Tsing Hua Univ Dept Mech Engn Beijing 100084 Peoples R China

In order to evaluate the main factors influencing the core-shooting process and to optimize the design of core boxes, the fluid-particle (air-sand) model has been built based on the two-phase flow theory. The fluid phase, air, and the particulate phase, sand granules, have been treated as a continuum. By using this model, it is possible to simulate the flow and compaction behavior of sand particles during the core-shooting process. To benchmark the calculated results, the shooting process has been recorded with a digital high speed camera, and the inlet condition of sand particles has also been achieved by using the camera. The preliminary results have showed that the calculation is in agreement with the testing results.

关键词： A Study on Numerical Simulation of Core-Shooting Process Core Simulation