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The use of an SQP algorithm in slope stability analysis

COMMUNICATIONS IN NUMERICAL METHODS IN ENGINEERING 2005年第1期21卷 23-37页

作者： Chen, J Yin, JH Lee, CF Hong Kong Polytech Univ Dept Civil & Struct Engn Kowloon Hong Kong Peoples R China Univ Hong Kong Dept Civil Engn Hong Kong Hong Kong Peoples R China

In the upper bound approach to limit analysis of slope stability based on the rigid finite element method, the search for the minimum factor of safety can be formulated as a non-linear programming problem with equality constraints only based on a yield criterion, a flow rule, boundary conditions, and an energy-work balance equation. Because of the non-linear property of the resulting optimization problems, a non-linear mathematical programming algorithm has to be employed. In this paper, the relations between the numbers of nodes, elements, interfaces, and subsequent unknowns and constraints in the approach have been derived. It can be shown that in the large-scale problems, the unknowns are subject to a highly sparse set of equality constraints. Because of the existence of non-linear equalities in the approach, this paper applies first time a special sequential quadratic programming (SQP) algorithm, feasible SQP (FSQP), to obtain solutions for such non-linear optimization problems. In FSQP algorithm, the non-linear equality constraints are turned into inequality constraints and the objective function is replaced by an exact penalty function which penalizes non-linear equality constraint violations only. Three numerical examples are presented to illustrate the potentialities and efficiencies of the FSQP algorithm in the slope stability analysis. Copyright (C) 2004 John Wiley Sons, Ltd.

关键词： sequential quadratic programming slope stability limit analysis upper bound rigid finite element method non-linear programming

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Optimization methods for the verification of second order sufficient conditions for bang-bang controls

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OPTIMAL CONTROL APPLICATIONS & METHODS 2005年第3期26卷 129-156页

作者： Maurer, H Büskens, C Kim, JHR Kaya, CY Univ Munster Inst Numer Math D-48149 Munster Germany Univ Bremen Zentrum Technomath Fachbereich 3 Bremen Germany Univ S Australia Sch Math & Stat Mawson Lakes SA 5095 Australia

It has been common practice to find controls satisfying only necessary conditions for optimality, and then to use these controls assuming that they are (locally) optimal. However, sufficient conditions need to be used to ascertain that the control rule is optimal. Second order sufficient conditions (SSC) which have recently been derived by Agrachev, Stefani, and Zezza, and by Maurer and Osmolovskii, are a special form of sufficient conditions which are particularly suited for numerical verification. In this paper we present optimization methods and describe a numerical scheme for finding optimal bang-bang controls and verifying SSC. A straightforward transformation of the bang-bang arc durations allows one to use standard optimal control software to find the optimal are durations as well as to check SSC. The proposed computational verification technique is illustrated on three example applications. Copyright (c) 2005 John Wiley & Sons, Ltd.

关键词： bang-bang control second order sufficient conditions non-linear programming control of a van der Pol oscillator control of a batch reactor robot control

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Optimum design of plane timber trusses considering joint flexibility

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ENGINEERING STRUCTURES 2005年第1期27卷 145-154页

作者： Silih, S Premrov, M Kravanja, S Univ Maribor Fac Civil Engn SLO-2000 Maribor Slovenia

The paper presents the optimization of metal-plate-connected plane timber trusses with special emphasis on joint flexibility. The optimization was performed by the non-linear programming approach. Since various truss design parameters such as type of truss configuration, span/depth ratio, number and type of diagonal and vertical members and type of joint connections simultaneously affect each other, it is proposed that all of these parameters should be considered simultaneously in a single mathematical model. An optimization model for cost optimization of timber trusses was thus developed. The economic objective function for minimizing the structure's self-manufacturing costs was defined, subjected to the design, stress and deflection (in)equality constraints. The finite element equations were as the equality constraints defined for the calculation of the internal forces and the deflections of the structure. The stiffness matrix of the structure was composed by considering fictitiously decreased cross-section areas of all the flexibly connected elements. Constraints for the dimensioning of the timber members were determined in accordance with Eurocode 5 in order to satisfy the requirements of both the ultimate and the. serviceability limit states. The cross-section dimensions and the number of fasteners were defined as independent optimization variables. A numerical example demonstrates the applicability of the optimization approach presented as well as the influence of the fasteners' flexibility on the optimal self-manufacturing costs. (C) 2004 Elsevier Ltd. All rights reserved.

关键词： timber trusses fasteners flexibility optimization non-linear programming

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Lower bound shakedown analysis by the symmetric Galerkin boundary element method

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INTERNATIONAL JOURNAL OF PLASTICITY 2005年第1期21卷 21-42页

作者： Liu, YH Zhang, XF Cen, ZZ Tsing Hua Univ Dept Engn Mech Beijing 100084 Peoples R China

In this paper, the static shakedown theorem is reformulated making use of the symmetric Galerkin boundary element method (SGBEM) rather than of finite element method. Based on the classical Melan's theorem, a numerical solution procedure is presented for shakedown analysis of structures made of elastic-perfectly plastic material. The self-equilibrium stress field is constructed by linear combination of several basis self-equilibrium stress fields with parameters to be determined. These basis self-equilibrium stress fields are expressed as elastic responses of the body to imposed permanent strains obtained through elastic-plastic incremental analysis. The lower bound of shakedown load is obtained via a non-linear mathematical programming problem solved by the Complex method. Numerical examples show that it is feasible and efficient to solve the problems of shakedown analysis by using the SGBEM. (C) 2004 Elsevier Ltd. All rights reserved.

关键词： SGBEM lower bound shakedown analysis non-linear programming complex method

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GLOBAL CONVERGENCE RESULTS OF A THREE TERM MEMORY GRADIENT METHOD WITH A non-MONOTONE LINE SEARCH TECHNIQUE

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Acta Mathematica Scientia 2005年第1期25卷 170-178页

作者：孙清滢 Department of Applied Mathematics University of Petroleum Dongying 257061 China Department of Applied Mathematics Dalian University of Technology Dalian 116024 China

In this paper, a new class of three term memory gradient method with non-monotone line search technique for unconstrained optimization is presented. Global convergence properties of the new methods are discussed. Combining the quasi-Newton method with the new method, the former is modified to have global convergence property. Numerical results show that the new algorithm is efficient.

关键词： non-linear programming three term memory gradient method convergence non-monotone line search technique numerical experiment

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Low-energy localized clustering: An adaptive cluster radius configuration scheme for topology control in wireless sensor networks

Low-energy localized clustering: An adaptive cluster radius ...

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61st IEEE Vehicular Technology Conference

作者： Kim, J Kim, S Kim, D Lee, W Kim, E Korea Univ Dept Comp Sci & Engn Seoul 136701 South Korea

ISBN: (纸本)0780388879

This paper addresses an adaptive and dynamic localized scheme unique to hierarchical clustering protocols in wireless sensor networks, while reducing the consumption of residual energy of cluster heads and as a result delivering a prolonged the sensor network lifetime. Our proposed scheme, Low-Energy Localized Clustering (LLC), aims to minimize energy consumption of cluster heads while the entire sensor network is still being covered. For achieving this goal, LLC dynamically regulates the radius of each cluster. Through a simulation based performance of this algorithm, LLC, we show that our novel cluster radius configuration algorithm achieves the desirable properties.

关键词： wireless sensor network localized clustering topology control non-linear programming

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Effect of localized optimal clustering for reader anti-collision in RFID networks: Fairness aspects to the readers

Effect of localized optimal clustering for reader anti-colli...

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14th International Conference on Computer Communications and Networks

作者： Kim, J Lee, W Yu, JE Kim, E Lee, C Korea Univ Dept Comp Sci & Engn Seoul 136701 South Korea

ISBN: (纸本)0780394283

This paper proposes an adaptive and dynamic localized scheme unique to hierarchical clustering in RFID networks, while reducing the overlapping areas of clusters and consequently reducing collisions among RFID readers. Drew on our LLC scheme that adjusts cluster coverage to minimize energy consumption, Low-Energy Localized Clustering for RFID networks (LLCR) addresses RFID reader anti-collision problem in this paper. LLCR is a RFID reader anti-collision algorithm that minimizes collisions by minimizing overlapping areas of clusters that each RFID reader covers. LLCR takes into account each RFID reader's energy state as well as RFID reader collisions. For the energy state factor, we distinguish homogeneous RFID networks from heterogeneous ones according to computing power of each RFID reader. Therefore, we have designed efficient homo-LLCR and hetero-LLCR schemes for each case. Our simulation-based performance evaluation shows that LLCR minimizes energy consumption and overlapping areas of clusters of RFID readers.

关键词： RFID anti-collision localized clustering topology control non-linear programming

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ON-LINE PULP MILL PRODUCTION OPTIMIZATION

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IFAC Proceedings Volumes 2005年第1期38卷 443-448页

作者： Jens Pettersson Ulf Persson Thomas Lindberg Lars Ledung Xiaojing Zhang ABB Corporate Research Västerås Sweden ABB Automation Technologies Västerås Sweden

We consider the planning of pulp production for large sulphate and sulfite mills. The production planning problem is formulated as a non-linear program (NLP) given a process model of the mill as constraint. The objective is to minimize the usage of expensive chemicals and to minimize the (squared) deviation from specified set-points for selected variables, e.g. production, tank-level and chemical composition of the cooking liquor. The problem formulation also considers upper and lower limits on variables and limitations in the derivative of production related variables. The NLP, which involves several tens of thousands of variables, is solved using algorithms for large-scale optimization. To provide a correct initial state of the process model, a moving horizon estimation is done to estimate the current state of the process. A model library consisting of common process units in pulp mills have been developed. The models are described by differential algebraic equations. A software platform, which enables the user to assemble complex process models of complete mills based on the model library, has been developed. The platform also serves as data collector for the measured values from process sensors, as well as storing optimized and estimated values. The pulp mill production planning system is installed on-line at Billerud Gruvön, a large Swedish integrated pulp and paper mill, producing some 660000 tons of sulphate and sulfite pulp.

关键词： Process control optimal control state estimation non-linear programming

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Estimating the attribute weights through evidential reasoning and mathematical programming

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INTERNATIONAL JOURNAL OF INFORMATION TECHNOLOGY & DECISION MAKING 2004年第3期3卷 419-428页

作者： Deng, MR Xu, WX Yang, JB Zhejiang Univ Sch Management Inst Decis & Optimisat Hangzhou 310027 Peoples R China Chinese Acad Sci Inst Policy & Management Beijing 100080 Peoples R China Univ Manchester Inst Sci & Technol Manchester M60 1QD Lancs England

An approach for estimating attribute weight is proposed, which is addressed to the problem inverse to the aggregation assessment based on a hierarchy of attributes. Evidential reasoning framework is employed since the assessment on some basic attributes may be uncertain and incomplete. As a by-product, a simple formula for evidence combination for our special case is obtained. The weights are estimated based on the preference given by the decision-maker, and represented as intervals. The more abundant preference the decision-maker shows, the clearer the relation among the basic attributes.

关键词： weight estimation evidential reason non-linear programming

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Modular product design with grouping genetic algorithm - a case study

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COMPUTERS & INDUSTRIAL ENGINEERING 2004年第3期46卷 443-460页

作者： Kreng, VB Lee, TP Natl Cheng Kung Univ Sch Ind Management Tainan 701 Taiwan

Modular products are products that fulfill various functions through the combination of distinct modules. These detachable modules are constructed both according to the maximum physical and functional relations among components and maximizing the similarity of specifically modular driving forces. Accordingly, a non-linear programming is proposed to identify separable modules and simultaneously optimize the number of modules. This paper presents a systematic approach to accomplish modular product design in four major phases. Phase 1 is by means of functional and physical interaction analysis to format a component-to-component correlation matrix. Phase 2 is the exploration of design requirements to evaluate the relative importance of each modular driver. In phase 3, non-linear programming is used to formulate the objective function. In the final phase, a heuristic grouping genetic algorithm is adopted to search for the optimal or near-optimal modular architecture. This process and its application are illustrated by a real case of an electrical consumer product provided by an Original Design Manufacturer. The results demonstrate that the designer could direct a new approach to establish product modules according to the relative importance of modular drivers and the interaction among components. (C) 2004 Elsevier Ltd. All rights reserved.

关键词： modular product design non-linear programming grouping genetic algorithm

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