检索结果-内蒙古大学图书馆

Exact solutions to linear programming problems

OPERATIONS RESEARCH LETTERS 2007年第6期35卷 693-699页

作者： Applegate, David L. Cook, William Dash, Sanjeeb Espinoza, Daniel G. Univ Chile Dept Ingn Ind Santiago 8370439 Chile AT&T Labs Res Florham Pk NJ 07932 USA Georgia Inst Technol Sch Ind & Syst Engn Atlanta GA 30332 USA IBM Corp Thomas J Watson Res Ctr Yorktown Hts NY 10598 USA

The use of floating-point calculations limits the accuracy of solutions obtained by standard LP software. We present a simplex-based algorithm that returns exact rational solutions, taking advantage of the speed of floating-point calculation, and attempting to minimize the operations performed in rational arithmetic. Extensive computational results are presented. (C) 2007 Elsevier B.V. All rights reserved.

关键词： linear programming simplex algorithm rational arithmetic

来源：评论

学校读者我要写书评

暂无评论

Optimal Frequency Diverse Subarray Design With Cramer-Rao Lower Bound Minimization

引用

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2015年 14卷 1188-1191页

作者： Wang, Yongbing Wang, Wen-Qin Chen, Hui Shao, Huaizong Univ Elect Sci & Technol China Sch Commun & Informat Engn Chengdu 611731 Peoples R China Univ London Imperial Coll Sci Technol & Med London SW7 2AZ England

This letter proposes an optimal subarray design strategy for frequency diverse array (FDA) radar target localization via Cramer-Rao lower bound (CRLB) minimization. To decouple the range and angle response of targets, we divide the FDA transmit array elements into multiple subarrays. For a given number of array elements and subarrays, the optimal array division and frequency increments design strategies are formulated as a constrained CRLB minimization problem. Then it is converted into an unconstrained optimization problem and further resolved by iteratively utilizing the Nelder-Mead algorithm. Numerical results show that, under the same condition, FDA radar localization performance is significantly improved by employing the CRLB minimization strategy.

关键词： Array design Cramer-Rao lower bound (CRLB) direction-of-arrival (DOA) frequency diverse array (FDA) localization simplex algorithm subarray

来源：评论

学校读者我要写书评

暂无评论

Computational and theoretical pitfalls in some current performance measurement techniques;and a new approach

引用

APPLIED MATHEMATICS AND COMPUTATION 2006年第2期181卷 1199-1207页

作者： Soleimani-damaneh, M. Jahanshahloo, G. R. Abbasbandy, S. Teacher Training Univ Dept Math Tehran 15618 Iran Imam Khomeini Univ Dept Math Qazvin Iran

This paper addresses some pitfalls of some fuzzy data envelopment analysis models which have been provided in recent published papers. This study deals with these papers from both computational and theoretical points of view. Moreover, a new approach to deal with fuzzy data in DEA framework is provided, which does not have the mentioned pitfalls. (c) 2006 Elsevier Inc. All rights reserved.

关键词： linear programming duality simplex algorithm data envelopment analysis fuzzy data envelopment analysis

来源：评论

学校读者我要写书评

暂无评论

An equilibrium method for the global computation of critical configurations of elastic linkages

引用

COMPUTERS & STRUCTURES 2013年 121卷 50-63页

作者： Kocsis, Attila Budapest Univ Technol & Econ Dept Struct Mech H-1111 Budapest Hungary

In this paper we develop an equilibrium method for the derivation of critical equilibrium configurations of a non-linearly elastic, discrete rod model, which is supported in a statically indeterminate way, and subjected to general loading. We construct a global computation scheme for the critical equilibrium configurations and demonstrate the effectiveness of the method via a clamped-pinned rod fabricated from linearly elastic, or specially hardening/softening material, loaded by either a horizontal or a follower force. We show some correspondence between the equilibrium states of these two load cases, and different snapping processes are revealed. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Equilibrium paths Buckling Critical load simplex algorithm Equilibrium method Snapping

来源：评论

学校读者我要写书评

暂无评论

Software relocation of 3D surface topography measurements

引用

INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE 2001年第13-14期41卷 2095-2101页

作者： Condeço, J Christensen, LH Rosén, BG Danish Technol Inst Ctr Surface Anal Tastrup Denmark

In a number of 3D surface topography measurements it is both necessary and of great use to relocate exactly the same area, e.g., in the study of wear processes, in correlation studies of slightly overlapping characterisation techniques, and in the study of replica techniques. The objective of the present paper is to evaluate the performance of an automatic relocation process based on a simplex algorithm. The method is implemented in MATLAB(TM). The cross-correlation coefficient between the topographical data determines the evolution of the relocation process. Two variations of the method are used, i.e., one uses the full range of the input data and the second uses a truncated version of the input data. The truncation is based in selected percentages of the bearing area curve. Four different surfaces and two different techniques are used in this study. (C) 2001 Elsevier Science Ltd. All rights reserved.

关键词： surface topography relocation simplex algorithm

来源：评论

学校读者我要写书评

暂无评论

Artificial Intelligence Mechanisms on Interactive Modified simplex Method with Desirability Function for Optimising Surface Lapping Process

引用

MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-16页

作者： Luangpaiboon, Pongchanun Duangkaew, Sitthikorn Thammasat Univ Fac Engn Dept Ind Engn Ind Stat & Operat Res Unit Pathum Thani 12120 Thailand

A study has been made to optimise the influential parameters of surface lapping process. Lapping time, lapping speed, downward pressure, and charging pressure were chosen from the preliminary studies as parameters to determine process performances in terms of material removal, lap width, and clamp force. The desirability functions of the-nominal-the-best were used to compromise multiple responses into the overall desirability function level or D response. The conventional modified simplex or Nelder-Mead simplex method and the interactive desirability function are performed to optimise online the parameter levels in order to maximise the D response. In order to determine the lapping process parameters effectively, this research then applies two powerful artificial intelligence optimisation mechanisms from harmony search and firefly algorithms. The recommended condition of (lapping time, lapping speed, downward pressure, and charging pressure) at (33, 35, 6.0, and 5.0) has been verified by performing confirmation experiments. It showed that the D response level increased to 0.96. When compared with the current operating condition, there is a decrease of the material removal and lap width with the improved process performance indices of 2.01 and 1.14, respectively. Similarly, there is an increase of the clamp force with the improved process performance index of 1.58.

关键词： ARTIFICIAL intelligence simplex algorithm MATHEMATICAL optimization PARAMETER estimation MATHEMATICAL analysis STATISTICS

来源：评论

学校读者我要写书评

暂无评论

Sparsity Prevention Pivoting Method for Linear Programming

引用

IEEE ACCESS 2018年 6卷 19560-19567页

作者： Li, Peiqiang Li, Qiyuan Li, Canbing Zhou, Bin Cao, Yijia Wu, Qiuwei Fang, Baling Hunan Univ Coll Elect & Informat Engn Changsha 410082 Hunan Peoples R China Hunan Univ Hunan Key Lab Intelligent Informat Anal & Integra Changsha 410082 Hunan Peoples R China Tech Univ Denmark Ctr Elect Power & Energy Dept Elect Engn DK-2800 Lyngby Denmark Hunan Univ Technol Coll Elect & Informat Engn Zhuzhou 412007 Peoples R China

When the simplex algorithm is used to calculate a linear programming (LP) problem, if the matrix is a sparse matrix, it will be possible to lead to many zero-length calculation steps, and even iterative cycle will appear. To deal with the problem, a new pivoting method is proposed in this paper. The principle of this method is to avoid choosing the row which the value of the element in the right side of constraint expression for LP in this row is zero as the row of the pivot element to make the matrix in LP density and ensure that most subsequent steps will improve the value of the objective function. One step following this principle is inserted in the existing LP algorithm to reselect the pivot element. Both the conditions for inserting this step and the maximum number of allowed insertion steps are determined. In the case study, taking several numbers of LP problems as examples, the results indicate that this method can effectively improve the efficiency of LP for the sparse matrix.

关键词： Linear programming pivoting rules simplex algorithm sparse matrix

来源：评论

学校读者我要写书评

暂无评论

Generalized column generation for linear programming

引用

MANAGEMENT SCIENCE 2002年第3期48卷 444-452页

作者： Oguz, O Bilkent Univ Dept Ind Engn Ankara Turkey

Column generation is a well-known and widely practiced technique for solving linear programs with too many variables or constraints to include in the initial formulation explicitly. Instead, the required column information is generated at each iteration of the simplex algorithm. This paper shows that, even if the number of variables is low enough for explicit inclusion in the model with the available technology, it may still be more efficient to resort to column generation for some class of problems.

关键词： column generation simplex algorithm linear programming

来源：评论

学校读者我要写书评

暂无评论

Optimizing Gradient Methods for IoT Applications

引用

IEEE INTERNET OF THINGS JOURNAL 2022年第15期9卷 13694-13704页

作者： Hosseini, Eghbal Reinhardt, Line Rawat, Danda B. Roskilde Univ Dept People & Technol DK-4000 Roskilde Denmark Howard Univ Dept Elect Engn & Comp Sci Washington DC 20059 USA

Solving linear programming (LP) and nonlinear programming (NLP) problems is momentous because of their wide applications in real-life problems. There is no unified way to find the global optimum for NLPs. But on the other hand, the simplex algorithm, as the dominating methodology for LPs for several decades moves only on the boundary (vertices) and ignores the vast majority of the feasible region in the process of searching. In this article, we study two gradient-based methodologies that explore the whole feasible region, which guarantee faster convergence rates for both LP and NLP optimization problems including IoT problems such as Software-Defined Internet of Vehicles (SDIoV) and vehicular ad hoc networks (VANETs). The gradient-simplex algorithm (GSA) for LPs, which moves inside the feasible region in the gradient direction at first to reduce the search space and then explores the reduced boundary to find an optimal solution. The evolutionary-gradient algorithm (EGA), on the other hand, is for NLPs and uses an evolutionary population to estimate gradients by evolving to find better solutions in steps. Based on extensive simulations, the obtained numerical results show that both approaches provide efficient solutions and outperform the state-of-the-art methods on optimization problems with large feasible spaces. Comparative results of applying the GSA on SDIoV and VANETs with different sizes are included.

关键词： Statistics Sociology Internet of Things Approximation algorithms Software algorithms Linear programming Optimization Evolutionary population feasible region gradient function Internet of Things simplex algorithm

来源：评论

学校读者我要写书评

暂无评论

An Optimization Formulation of Converter Control and Its General Solution for the Four-Leg Two-Level Inverter

引用

IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY 2018年第5期26卷 1901-1908页

作者： Bouarfa, Abdelkader Bodson, Marc Fadel, Maurice Univ Toulouse INPT CNRS UPSLAPLACE F-31071 Toulouse France Univ Utah Dept Elect & Comp Engn Salt Lake City UT 84112 USA

This brief proposes an optimization formulation of the control problem for power electronic converters. A benefit of the approach is a systematic method for the control of high-switch-count static converters. In the case of the three-phase, four-leg, two-level inverter, the framework provides a characterization of all the possible solutions that yield a maximal extension of the inverter linearity range. The method makes it possible to recover well-known modulation strategies as well as to discover some new ones having different properties and distinct advantages. The characteristics resulting from different design choices are evaluated in simulations, with consideration being given to the linearity range, total harmonic distortion, and switching losses. Key principles of extension of the proposed method to multilevel, multileg converters are given, as well as motivations for a field-programmable gate array-based hardware implementation enabling real-time pulsewidth modulation control.

关键词： Control allocation four-leg two-level inverter median-voltage injection optimization pulsewidth modulation (PWM) simplex algorithm voltage control voltage-source inverter

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：