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A PARTITIONING PARALLEL PROCEDURE FOR NUMERICAL SIMULATION OF GAS FLOW IN A CYCLONE SEPARATOR

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Journal of Hydrodynamics 2002年第1期14卷 52-58页

作者： Huang Rong-guo, Huan Bo-wen, Zhang Shu-ping (School of Power and Energy engineering, shanghai jiaotong Univers ity, shanghai 200240, china) School of Power and Energy engineering Shanghai Jiaotong University shanghai 200240 China

Based on the SIMPLE-C algori thm and the non-overlapping Domain Decomposition Method (DDM), in which the Dirichlet-N eumann alternative algorithm is employed, a partitioning parallel procedure was developed to numerically simulate fluid flow in complex 3-D domains. It can well remove the limitation of speed and capacity of personal computer on large-scale numerical simulation of complex 3-D domains. In this paper, the 3-D turbulent swirling gas flow in cyclone separator was simulated. In view of the physica l reality, the computational results are bascally reasonable.

关键词： SIMPLE-C algorithm Domain Decompos ition Method (DDM) Dirichlet-Neumann alternative algorithm cyclone separator

Topology-aware Overlay Multicast over IP Multicast Networks

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Journal of shanghai jiaotong university(science) 2008年第1期13卷 91-96页

作者：陈逍邵华钢汪为农 department of computer science and engineering Shanghai Jiaotong University Regional Network Center of East china

Most existing overlay multicast approaches refuse to consider any network layer support no matter whether it is available or not. This design principle greatly increases the complexity of the routing algorithms and makes the overlay topologies incompatible with the underlying network. To address these issues, topology-aware overlay multicast over IP multicast networks (TOMIMN) was proposed as a novel overlay multicast protocol, which exploits the cooperation between end-hosts and IP multicast routers to construct a topology-aware overlay tree. Through a little modification to protocol independent multicast sparse mode (PIM-SM), a multicast router is able to receive registration from nearby group members and redirect passing-by join requests to them. Due to the multicast router's support, TOMIMN organizes its group members into an overlay multicast tree efficiently, which matches the physical network topology well.

关键词： overlay networking network architecture overlay multicast

A QoS Aware Service Composition Protocol in Mobile Ad Hoc Networks

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Journal of shanghai jiaotong university(science) 2008年第2期13卷 226-232页

作者：韩松乔张申生张勇曹健 department of computer science and engineering Shanghai Jiaotong University

A novel decentralized service composition protocol was presented based on quality of service (QoS) for mobile ad hoc networks (MANETs).A service composition in MANETs is considered as a service path discovery in a service *** on the concept of source routing,the protocol integrates route discovery, service discovery and service composition and utilizes a constrained flooding approach to discover the optimal service path.A service path maintenance mechanism was exploited to recover broken service *** experiments demonstrate that the proposed protocol outperforms existing service composition protocols.

关键词： service composition mobile ad hoc network quality of service

Electromagnetic Filtration of Primary Fe-Rich Phases from Al-Si Alloy Melt

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Journal of Materials science & Technology 2001年第3期17卷 306-310页

作者： Zhenming XU, Tianxiao LI, Da SHU and Yaohe ZHOU School of Materials science and engineering, shanghai jiaotong university, shanghai 200030, china E-mail: zmxu@*** Sch. of Mat. Sci. and Eng. Shanghai Jiaotong Univ. Shanghai 200030 China

Electromagnetic filtration of primary Fe-rich phases (complex compound of AlFeSiMn) from Al-Si alloy melt containing 1.2 wt pct Fe have been studied by theoretical analysis and on a self-designed electromagnetic filtration equipment. The principle of the electromagnetic filtration is that the EMF (electromagnetic force) scarcely acts on the primary Fe-rich phases having low electric conductivity, which are then moved in the direction opposite to that of the EMF. Experimental results show that the primary Fe-rich phases are separated from Al-Si alloy melt and are collected in the filter while the melt is in horizontal flow. The removal efficiency of the primary iron-phases (77) calculated is less as the greatest flow velocity of the melt (UM) and the height of the filter (2h) are larger, while it becomes larger as EMF, operating distance of electromagnetic force (cr) and particle size (dv) become larger. It has been confirmed that the primary iron-phases larger than 20 jim can be removed efficiently by theoretical analysis and experiments. This new technique is high efficient and available for continuously flowing melts as compared with natural settling and filtration methods, which offer a possibility for recycling high quality aluminum alloys.

关键词： Fe Al Electromagnetic Filtration of Primary Fe-Rich Phases from Al-Si Alloy Melt Si

Pseudo-Random Sequences Generator Based on Discrete Hyperchaotic Systems

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Journal of Systems engineering and Electronics 2003年第4期14卷 84-89页

作者： Li Changgang & Han Zhengzhi department of Automation, shanghai jiaotong university, shanghai 200030, P. R. china department of Automation Shanghai Jiaotong University Shanghai 200030 P. R. China

We first design a discrete hyperchaotic system via piece-wise linear state feedback. The states of the closed loop system are locally expanding in two directions but absolutely bounded on the whole, which implies hyperchaos. Then, we use three suchlike hyperchaotic systems with different feedback gain matrices to design a pseudo-random sequence generator (PRSG). Through a threshold function, three sub-sequences generated from the output of piecewise linear functions are changed into 0-1 sequences. Then, followed by XOR operation, an unpredictable pseudo-random sequence (PRS) is ultimately obtained. The analysis and simulation results indicate that the PRS, generated with hyperchaotic systems, has desirable statistical features.

关键词： discrete hyperchaotic system piecewise linear state feedback pseudo-random sequences.

Nonlinear Control for Autonomous Underwater Glider Motion Based on Inverse System Method

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Journal of shanghai jiaotong university(science) 2010年第6期15卷 713-718页

作者：杨海马捷 State Key Laboratory of Ocean engineering Shanghai Jiaotong University

Autonomous underwater gliders are highly effcient,buoyancy-driven,winged autonomous underwater vehicles. Their dynamics are multivariable nonlinear systems. In addition,the gliders are underactuated and diffcult to maneuver,and also dependent on their operational environment. To confront these problems and to design an effective controller,the inverse system method was used to decouple the original system into two independent single variable linear subsystems. The stability of the zero dynamics was analyzed,and an additional closed-loop controller for each linear subsystem was designed by sliding mode control method to form a type of composite controller. Simulation results demonstrate that the derived nonlinear controller is able to cope with the aforementioned problems simultaneously and satisfactorily.

关键词： underwater glider nonlinear control inverse system method zero dynamics

STUDY ON SINGULAR CONFIGURATIONS AND computer SIMULATION OF 6R ROBOT

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Chinese Journal of Mechanical engineering 2004年第2期17卷 177-180页

作者： Zhang Kai Hu Dejin Liu Chengliang School of Mechanical engineering,shanghai jiaotong university,shanghai 200030, china School of Mechanical engineering Shanghai Jiaotong University 上海 200030

When robot is at singular configuration, the limited hand velocity wouldrequire some joints with infeasible speeds so as to lead unsafely of the system. A method of solvingthe approximate velocity of joint near singular configuration point by adding damped vector isproposed and a modified algorithm is provided. With the analysis of J^(-1) the singularconfigurations of 6R robot are divided into structure boundary singularity , boundary singularity ,inner singularity and wrist singularity. The conditions of singularities of the robot have beenascertained. The computer simulations of the singularities of the robot are developed, which havemany advantages over previous description methods of the singular configurations of robot. With thehelp of boundary singularity analysis, a application in welding trajectory planning checking of therobot has been carried out and the simulation result proved visualized and useful.

关键词： Robot Singular configuration computer simulation

SEEPAGE ANALYSIS OF LANDFILL FOUNDATIONS IN shanghai LAOGANG LANDFILL PHASE IV

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Journal of Hydrodynamics 2006年第5期18卷 613-619页

作者： ZHANG Qian-fei WANG Yan-ming XU Yong-fu School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University Shanghai 200030 China shanghai Municipal engineering Design Institute Shanghai 200092 China

A complex seepage flow field with unknown free surface was formed in the shanghai Laogang Municipal Solid Waste （MSW） Landfill by the perimeter cut-off wall around the landfill site and the Prefabricated Vertical Drains （PVD） in the foundation of landfill. First, the equivalent vertical permeability was presented based on the drainage mechanism of PVD and the related calculation method was studied to macroscopically reflect the impact of PVD on the seepage flow status of the landfill foundation. With the influence of the cut-off wall and the PVD on the infiltration of groundwater, the total inflow was classified into two parts： the lateral inflow through the cut-off wall outside the landfill, and the upward infiltration through the PVD from the foundation of the landfill. Seepage analysis was conducted using the finite element method according to the actual scenario of Laogang Landfill, and the lateral infiltration and the upward infiltration were calculated, respectively. The results show that the total inflow into the landfill area was mostly supplied by the upward infiltration through the PVD and the perimeter cut-off wall was significantly effective to depressurize the seepage pressure and to reduce the flow rate.

关键词： Municipal Solid Waste (MSW) landfill foundations of landfill cut-off wall Prefabricated Vertical Drain (PVD) lateral infiltration upward infiltration finite element analysis

An Improved Scalar Costa Scheme Based on Watson Perceptual Model

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Journal of shanghai jiaotong university(science) 2008年第1期13卷 26-29页

作者：齐开悦陈剑波周异 department of Electronic engineering Shanghai Jiaotong University School of Information Security Shanghai Jiaotong University Shanghai 200030 China

An improved scalar Costa scheme (SCS) was proposed by using improved Watson perceptual model to adaptively decide quantization step size and scaling factor. The improved scheme equals to embed hiding data based on an actual image. In order to withstand amplitude scaling attack, the Watson perceptual model was redefined, and the improved scheme using the new definition can insure quantization step size in decoder that is proportional to amplitude scaling attack factor. The performance of the improved scheme outperforms that of SCS with fixed quantization step size. The improved scheme combines information theory and visual model.

关键词： information hiding scalar costa scheme perceptual model quantization step size