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An edge-based smoothed finite element method for primal-dual shakedown analysis of structures

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING 2010年第7期82卷 917-938页

作者： Tran, Thanh Ngoc Liu, G. R. Nguyen-Xuan, H. Nguyen-Thoi, T. Natl Univ Singapore Dept Mech Engn Ctr Adv Computat Engn Sci Singapore 117576 Singapore Hanoi Architectural Univ Fac Civil Engn Hanoi Vietnam Singapore MIT Alliance Singapore 117576 Singapore

An edge-based smoothed finite element method (ES-FEM) using three-node linear triangular elements was recently proposed to significantly improve the accuracy and convergence rate of the standard finite element formulation for static, free and forced vibration analyses of solids. In this paper. ES-FEM is further extended for limit and shakedown analyses of structures. A primal dual algorithm based upon the von Mises yield criterion and a non-linear optimization procedure is used to compute both the upper and lower bounds of the plastic collapse limit and the shakedown limit. In the ES-FEM, compatible strains are smoothed over the smoothing domains associated with edges of elements. Using constant smoothing function, only one Gaussian point is required for each smoothing domain ensuring that the total number of variables in the resulting optimization problem is kept to a minimum compared with standard finite element formulation. Three benchmark problems are presented to show the stability and accuracy of solutions obtained by the present method. Copyright (C) 2009 John Wiley & Sons, Ltd.

关键词： limit analysis shakedown analysis duality non-linear programming edge-based smoothed finite element method (ES-FEM) strain smoothing

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Real-time optimization flow control

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COMPUTER NETWORKS 2010年第5期54卷 797-810页

作者： Dalalah, Doraid Jordan Univ Sci & Technol Fac Engn Dept Ind Engn Irbid 22110 Jordan

In this paper, we propose a dynamic optimization approach to end-to-end flow control in data networks. The objective is to maximize the aggregate utilities of the data sources over soft transmission rate bounds and delay constraints. The network links and data sources are considered as processors of a distributed computational system that has a global objective function. The presented model works with different shapes of utility curves under the proposition of elastic data traffic. The approach relies on real-time observations of the delay as a measure of the data network congestion at the routers (network nodes). A primal-dual algorithm carried out by the data sources is used to solve the optimization problem in a decentralized manner. The calculated transmission rates are bounded and the sources are subjected to a maximum number of data packets that can be queued downstream of each transmission session. The algorithm solves for the rates without the access to any network global information while each source calculates its transmission rate that should maximize the global objective function. The calculated optimal rates conform to rate-to-queue proportionality. Finally, we present an extensive simulation results to demonstrate the reliability of the algorithm. (C) 2009 Elsevier B.V. All rights reserved.

关键词： Data networks Flow control Optimization non-linear programming Duality

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Optimization based on quasi-Monte Carlo sampling to design state estimators for non-linear systems

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OPTIMIZATION 2010年第7期59卷 963-984页

作者： Alessandri, A. Cervellera, C. Maccio, D. Sanguineti, M. Univ Genoa Dept Commun Comp & Syst Sci DIST I-16145 Genoa Italy Univ Genoa Dept Prod Engn Thermoenerget & Math Models DIPTEM I-16129 Genoa Italy Natl Res Council Italy Inst Intelligent Syst Automat ISSIA CNR I-16149 Genoa Italy

State estimation for a class of non-linear, continuous-time dynamic systems affected by disturbances is investigated. The estimator is assigned a given structure that depends on an innovation function taking on the form of a ridge computational model, with some parameters to be optimized. The behaviour of the estimation error is analysed by using input-to-state stability. The design of the estimator is reduced to the determination of the parameters in such a way as to guarantee the regional exponential stability of the estimation error in a disturbance-free setting and to minimize a cost function that measures the effectiveness of the estimation when the system is affected by disturbances. Stability is achieved by constraining the derivative of a Lyapunov function to be negative definite on a grid of points, via the penalization of the constraints that are not satisfied. Low-discrepancy sampling techniques, typical of quasi-Monte Carlo methods, are exploited in order to reduce the computational burden in finding the optimal parameters of the innovation function. Simulation results are presented to investigate the performance of the estimator in comparison with the extended Kalman filter and in dependence of the complexity of the computational model and the sampling coarseness.

关键词： state estimation input-to-state stability ridge computational models constrained optimization non-linear programming quasi-Monte Carlo methods low-discrepancy sequences

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non-linear optimization of passive direct methanol fuel cell (DMFC)

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2010年第4期35卷 1759-1768页

作者： Basri, S. Kamarudin, S. K. Daud, W. R. W. Ahmad, M. M. Univ Kebangsaan Malaysia Inst Fuel Cell Bangi 43600 Selangor Malaysia Univ Kebangsaan Malaysia Dept Chem & Proc Engn Bangi 43600 Selangor Malaysia

The cost associated with a direct methanol fuel cell (DMFC) is the main drawback of its commercialization. To address this issue, the main objective of this study is to minimize the cost of micro DMFCs for portable applications. The model was coupled with a nonlinear constrained optimization to determine an optimum design of the DMFC with respect to the design and geometrical parameters of the anode and cathode, including methanol concentration, power density, catalyst loading, etc. optimization was performed using Matlab to minimize the difference between the power input required and the power optimum via non-linear programming (NLP). The optimum characteristics of DMFC were solved by using an NLP simulation. The outputs were verified by both experimental and modeling results. These dynamic optimization results provided an optimum design parameters for the physical properties of DMFC required to generate the portable application. Lastly, a cost analysis was also considered in this study. (c) 2009 Published by Elsevier Ltd on behalf of Professor T. Neiat Veziroglu.

关键词： Direct methanol fuel cell Optimization non-linear programming Economic analysis

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Research of Modified Quantum Genetic Algorithm and It's Application in Collision Detection

Research of Modified Quantum Genetic Algorithm and It's Appl...

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6th International Conference on Intelligent Computing

作者： Wu, Jue Chen, LiXue Yang, Lei Peng, LingXi Guangzhou Univ Coll Comp Sci & Educ Software Guangzhou 510006 Guangdong Peoples R China SW Univ Sci & Technol Coll Comp Sci & Technol Mianyang 621010 Sichuan Peoples R China SouthWest Petroleum Univ Coll Comp Sci & Technol Chengdu Peoples R China Guangzhou univ Coll Comp sci & educat software Guangzhou 510006 Guangdong Peoples R China

ISBN: (纸本)9783642148309

Collision detection is very important for improving the truth and immersion in the virtual environment. The paper analyzes the problems that exist in the normal algorithm. And there is no algorithm which is suitable to every situation. And the more complex the situations are, the more inefficient the algorithm is. The paper converts the problem of the collision detection to the non-linear programming problem with restricted condition. And use the modified quantum genetic algorithm to solve this problem. The results show that this method is efficient, especially in large-scale scenes.

关键词： Collision detection Quantum genetic algorithm non-linear programming

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Signaling system selection based on a full fuzzy hierarchical-TOPSIS algorithm

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INTERNATIONAL JOURNAL OF MANAGEMENT SCIENCE AND ENGINEERING MANAGEMENT 2010年第5期5卷 393-400页

作者： Lessan, Javad Mirabadi, Ahmad Jeddi, Yaser Gholamzadeh Iran Univ Sci & Technol Sch Railway Engn Tehran *** Iran Bu Ali Sina Univ Dept Ind Engn Hamadan 65174 Iran

This paper proposes a full fuzzy TOPSIS as an optimization model for railway signaling system selection issue. The study is a new approach to such problems in railway domain. Analysis of the obtained results is explained and they indicate that the proposed approach as full fuzzy decision support model is a feasible and practical approach. The approach needs no defuzzification and it considers both the qualitative and quantitative. The fuzzy approach is employed to cope with imprecision in the assessment of the relative importance of criteria and alternatives. In proposed method given a linguistic verbal judgment matrix, fuzzy normalized judgment matrix is constructed by implementing a new developed normalization method. Then the fuzzy scores of the alternatives are determined based on solving of a non-linear programming model. Finally the ranks of the alternatives are determined through a fuzzy ranking method. The aforementioned algorithm was applied in one of the railway lines of Iran.

关键词： signaling system selection fuzzy multi criteria decision making fuzzy-TOPSIS non-linear programming fuzzy ranking

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Bilateral Transactions Determination with Minimum Deviations in Economic Dispatch and Losses in Hybrid Electricity Markets

Bilateral Transactions Determination with Minimum Deviations...

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IEEE-Power-and-Energy-Society General Meeting

作者： Kumar, Ashwani Gao, Wenzhong NIT Dept Elect Engn Kurukshetra Haryana India Tennessee Technol Univ Dept Elect & Comp Engn Cookeville TN 38505 USA

ISBN: (纸本)9781424483570

Negotiation of secure bilateral transactions has become an important issue for better operation, planning and management of competitive electricity markets. In this paper, secure bilateral transactions have been determined with minimum deviations in economic generation schedule and real power losses for hybrid electricity markets. The generation pattern and real and reactive power loss has been obtained for both pool and bilateral demand. The secure bilateral transaction has also been determined minimizing only deviations from the scheduled transactions. The results obtained with different cases have been compared. AC Distribution Factors (ACDF) considering the impact of slack bus have been utilized for determining the line flows to consider the impact of bilateral contracts. The proposed approach has been applied on IEEE 24-bus reliability test system (RTS).

关键词： Secure bilateral transaction matrix Transaction matrix pattern Generation pattern non-linear programming and AC distribution factors

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A non-linear programming approach to kinematic shakedown analysis of composite materials

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING 2006年第1期66卷 117-146页

作者： Li, HX Yu, HS Univ Oxford Dept Engn Sci Oxford OX1 3PJ England Univ Nottingham Sch Civil Engn Nottingham NG7 2RD England

Using a Representative volume element (RVE) to represent the microstructure of periodic composite materials, this paper develops a non-linear numerical technique to calculate the macroscopic shakedown domains of composites subjected to cyclic loads. The shakedown analysis is performed using homogenization theory and the displacement-based finite element method. With the aid of homogenization theory, the classical kinematic shakedown theorem is generalized to incorporate the microstructure of composites. Using an associated flow rule, the plastic dissipation power for an ellipsoid yield criterion is expressed in terms of the kinematically admissible velocity. By means of non-linear mathematical programming techniques, a finite element formulation of kinematic shakedown analysis is then developed leading to a non-linear mathematical programming problem subject to only a small number of equality constraints. The objective function corresponds to the plastic dissipation power which is to be minimized and an upper bound to the shakedown load of a composite is then obtained. An effective, direct iterative algorithm is proposed to solve the non-linear programming problem. The effectiveness and efficiency of the proposed numerical method have been validated by several numerical examples. This can serve as a useful numerical tool for developing engineering design methods involving composite materials. Copyright (c) 2005 John Wiley & Sons, Ltd.

关键词： shakedown analysis composite materials homogenization theory finite element method non-linear programming

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Quantum Immune Algorithm and Its Application in Collision Detection

Quantum Immune Algorithm and Its Application in Collision De...

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International Conference on Life System Modeling and Simulation / International Conference on Intelligent Computing for Sustainable Energy and Environment (LSMS-ICSEE)

作者： Wu, Jue Peng, LingXi Chen, LiXue Yang, Lei Guangzhou Univ Coll Comp Sci & Educ Software Guangzhou 510006 Guangdong Peoples R China SouthWest Petr Univ Coll Comp Sci & Technol Chengdu 610500 Sichuan Peoples R China SouthWest Univ Sci & Technol Coll Computer Sci & Technol MianiYang 621010 SiChuan Peoples R China Network & Data Secur Key Lab Sichuan Province Sichuan 611731 Peoples R China

ISBN: (纸本)9783642155963

Collision detection is very important to improve the truth and immersion in the virtual environment. Firstly the paper analyzes the problems that exist in traditional algorithms. There is no algorithm suitable to every situation, and the more complex the situations are, the more rapidly the efficiency declines. Secondly the paper analyses the problem of collision detection in theory, and then converts the problem of the collision detection to the non-linear programming problem with restricted conditions. In this paper, the definition of the distance between two objects and for which the quantum coding is given. Through the steps, such as quantum clone, quantum variation, the problem of collision detection is solved. Finally, the simulation test shows that the quantum-inspired immune algorithm has much more effective impact on solving the extreme-value problem compared to the traditional genetic algorithm. It is feasible to use the algorithm in collision detection.

关键词： collision detection quantum genetic algorithm non-linear programming

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Optimal design of underground gas storage

Optimal design of underground gas storage

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5th International Conference on High Performance Structures and Materials

作者： Kravanja, S. Zlender, B. Univ Maribor Fac Civil Engn Maribor Slovenia

ISBN: (纸本)9781845644642

This paper presents the cost optimization of an underground gas storage (UGS), designed from lined rock caverns (LRCs). The optimization is performed by the non-linear programming (NLP) approach. For this purpose, the NLP optimization model OPTUGS was developed. The model comprises the cost objective function, which is subjected to geomechanical and design constraints. It is proposed that the geotechnical problem will be solved simultaneously. In such a way, the optimization enables not only that the solution is optimal, but also that the rock mass achieves enough strength, stability and safety. It is proposed that the optimization will be performed for the phase of the conceptual design. The numerical example at the end of the paper demonstrates the efficiency of the introduced optimization approach.

关键词： underground gas storage UGS lined rock cavern LRC optimization non-linear programming NLP

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