检索结果-内蒙古大学图书馆

Lower-bound limit analysis by using the EFG method and non-linear programming

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING 2008年第3期74卷 391-415页

作者： Chen, Shenshen Liu, Yinghua Cen, Zhangzhi Tsinghua Univ Dept Engn Mech Beijing 100084 Peoples R China

Intended to avoid the complicated computations of elasto-plastic incremental analysis, limit analysis is an appealing direct method for determining the load-carrying capacity of structures. On the basis of the static limit analysis theorem, a solution procedure for lower-bound limit analysis is presented firstly, making use of the element-free Galerkin (EFG) method rather than traditional numerical methods such as the finite element method and boundary element method. The numerical implementation is very simple and convenient because it is only necessary to construct an array of nodes in the domain under consideration. The reduced-basis technique is adopted to solve the mathematical programming iteratively in a sequence of reduced self-equilibrium stress subspaces with very low dimensions. The self-equilibrium stress field is expressed by a linear combination of several self-equilibrium stress basis vectors with parameters to be determined. These self-equilibrium stress basis vectors are generated by performing an equilibrium iteration procedure during elasto-plastic incremental analysis. The Complex method is used to solve these non-linear programming sub-problems and determine the maximal load amplifier. Numerical examples show that it is feasible and effective to solve the problems of limit analysis by using the EFG method and non-linear programming. Copyright (C) 2007 John Wiley & Sons, Ltd.

关键词： limit analysis EFG method self-equilibrium stress non-linear programming Complex method

来源：评论

学校读者我要写书评

暂无评论

Open loop optimal downhill driving brake strategies using non-linear programming

引用

INTERNATIONAL JOURNAL OF HEAVY VEHICLE SYSTEMS 2007年第1期14卷 36-56页

作者： Lingman, Peter Duarte, Antonio Oliveira, Ricardo Chalmers Univ Technol Dept Appl Mech SE-41296 Gothenburg Sweden Volvo 3P Dept Chassis Engn SE-40508 Gothenburg Sweden

In this paper open loop optimal trajectories for downhill driving are described. Problem formulation including process modelling, model simplification, transformation into a finite optimisation problem, and implementation into the TOMLAB optimisation package are presented. Results show that there is a large potential in controlling the complete brake system of a heavy duty truck and thereby simultaneously improve both mean speed (transport efficiency) and component wear cost. The resulting optimal trajectories define the upper limit for what is theoretically achievable in a real, closed loop, controller implementation and can be used to both inspire and verify the development of such algorithms.

关键词： cruise control downhill driving fading auxiliary brakes AB foundation brakes FBs non-linear programming NLP optimal control

来源：评论

学校读者我要写书评

暂无评论

COLLISION AVOIDANCE IN COMMERCIAL AIRCRAFT FREE FLIGHT VIA NEURAL NETWORKS AND non-linear programming

引用

INTERNATIONAL JOURNAL OF NEURAL SYSTEMS 2008年第5期18卷 371-387页

作者： Christodoulou, Manolis A. Kontogeorgou, Chrysa Tech Univ Crete Dept Elect & Comp Engn Khania 73100 Crete Greece

In recent years there has been a great effort to convert the existing Air Traffic Control system into a novel system known as Free Flight. Free Flight is based on the concept that increasing international airspace capacity will grant more freedom to individual pilots during the enroute flight phase, thereby giving them the opportunity to alter flight paths in real time. Under the current system, pilots must request, then receive permission from air traffic controllers to alter flight paths. Understandably the new system allows pilots to gain the upper hand in air traffic. At the same time, however, this freedom increase pilot responsibility. Pilots face a new challenge in avoiding the traffic shares congested air space. In order to ensure safety, an accurate system, able to predict and prevent conflict among aircraft is essential. There are certain flight maneuvers that exist in order to prevent flight disturbances or collision and these are graded in the following categories: vertical, lateral and airspeed. This work focuses on airspeed maneuvers and tries to introduce a new idea for the control of Free Flight, in three dimensions, using neural networks trained with examples prepared through non-linear programming.

关键词： Free Flight neural networks non-linear programming

来源：评论

学校读者我要写书评

暂无评论

Hierarchical optimization of district heating plants by integrating evolutionary and non-linear programming algorithms

引用

APPLIED ENERGY 2024年 373卷

作者： Hassan, Muhammed A. Araji, Mohamad T. Univ Waterloo Sch Architecture 7 Melville St S Cambridge ON N1S 2H4 Canada Cairo Univ Fac Engn Mech Power Engn Dept Giza 12613 Egypt

In district heating systems, the capacity and types of energy sources, along with their control mechanisms to meet heating demands, are intricately linked. Effective planning must consider financial constraints and system operations, especially with thermal storage. Control methods can significantly influence sizing decisions by adjusting heat production and storage rates across different equipment. Addressing these issues concurrently is essential to maximize cost savings throughout the system's lifespan. This study addresses critical research gaps, such as the lack of integrated bi-level schemes that combine evolutionary and mathematical optimizers while maintaining original non-linear problem formulations. Specifically, it puts forward a novel tri-level optimization framework aimed at minimizing the lifecycle cost (LCC) of district heating plants, powered by a mix of green (solar thermal and biomass) and conventional (gas) heat sources, along with daily thermal storage. The three levels of this scheme are: i) a particle swarm optimizer (PSO) to explore capacities of heat production and storage devices to minimize LCC;ii) an interior-point optimizer (Ipopt) to minimize annual operating costs with explicit operational constraints;and iii) a simulation layer to enhance computational efficiency. Technical suggestions regarding the initialization and early termination of Ipopt to achieve the global optimal solution with reasonable computation time are described in detail. When applied to the multi-source plant, this methodology showed successful and rapid convergence of PSO towards feasible system designs. The study achieved a minimum LCC of 36.34 million USD, corresponding to a levelized cost of heat of 0.0256 USD/kWh, by maximizing green heat sources and using moderate-volume storage. Biomass fuel (74.8%) and capital costs of biomass (8.1%) and solar (7.9%) systems were the primary LCC contributors. Thermal storage enhanced operational flexibility;without it, the ga

关键词： District heating Solar energy Biomass Storage tank non-linear programming Particle swarm optimizer

来源：评论

学校读者我要写书评

暂无评论

SL method for computing a near-optimal solution using linear and non-linear programming in cost-based hypothetical reasoning

引用

KNOWLEDGE-BASED SYSTEMS 2002年第7期15卷 369-376页

作者： Ishizuka, M Matsuo, Y Univ Tokyo Sch Engn Dept Informat & Commun Engn Bunkyo Ku Tokyo 1138656 Japan

Hypothetical reasoning is an important framework for knowledge-based systems, however, its inference time grows exponentially with respect to problem size. In this paper, we present an understandable efficient method called slide-down and lift-up (SL) method which uses a linear programming technique for determining an initial search point and a non-linear programming technique for efficiently finding a near-optimal 0-1 solution. To escape from trapping into local optima, we have developed a new local handler, which systematically fixes a variable to a locally consistent value. Since the behavior of the SL method is illustrated visually, the simple inference mechanism of the method can be easily understood. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： hypothetical reasoning linear programming non-linear programming

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Duality in non-linear programming for limit analysis of not resisting tension bodies

引用

STRUCTURAL ENGINEERING AND MECHANICS 2007年第1期26卷 15-30页

作者： Baratta, A. Corbi, O. Univ Naples Federico II Dept Struct Engn I-80125 Naples Italy

In the paper, one focuses on the problem of duality in non-linear programming, applied to the solution of no-tension problems by means of Limit Analysis (LA) theorems for Not Resisting Tension (NRT) models. In details, one demonstrates that, starting from the application of the duality theory to the non-linear program defined by the static theorem approach for a discrete NRT model, this procedure results in the definition of a dual problem that has a significant physical meaning: the formulation of the kinematic theorem.

关键词： structural analysis operational research NRT model duality non-linear programming limit analysis

来源：评论

学校读者我要写书评

暂无评论

Determination of optimised cut-off grade utilising non-linear programming

引用

ARABIAN JOURNAL OF GEOSCIENCES 2015年第10期8卷 8963-8967页

作者： Yasrebi, Amir Bijan Wetherelt, Andy Foster, Patrick Kennedy, Gareth Ahangaran, Dariush Kaveh Afzal, Peyman Asadi, Ahmad Univ Exeter Cambome Sch Mines Penryn Cornwall England Islamic Azad Univ Dept Min Engn South Tehran Branch Tehran Iran

One of the most fundamental problems in a mining operation is how to recognise an optimum cut-off grade, which defines the grade for discriminating between ore and waste in an ore body, including ore that is extracted at different periods over a mine life period. Therefore, the identification of an optimised cut-off grade (COG) is a crucial function which has to be monitored during the mine life. The main aim of this study is to propose a modified optimum COG model in order to maximise the profit value (PV) for mining projects. Maximising the PV of a mining operation, which is a non-linear programming, is subject to different constraints involving a general grade distribution within a deposit and three stages of production namely mining, concentrating and refining. The proposed computer-based model is more effective in long-term planning of the open pit mines. To provide a better understanding of the algorithm efficiency, a numerical example is given and subsequently solved based on the Lane algorithm. In order to achieve this, the LINGO software was employed.

关键词： Cut-off grade (COG) Profit value (PV) non-linear programming Lane algorithm

来源：评论

学校读者我要写书评

暂无评论

Optimum blends of different grades of surimi determined by non-linear programming

引用

FISHERIES SCIENCE 2001年第3期67卷 500-505页

作者： Hsu, CK Chiang, BH Natl Taiwan Univ Grad Inst Food Sci & Technol Taipei 10764 Taiwan

The texture and color properties of surimi gels consisting of pollack surimi, golden threadfin-bream surimi, and low-grade hairtail surimi in various ratios were determined based on a mixture design. Surimi gels were produced by heating at 90 degreesC for 20 min with the addition of 2% NaCl. The texture and color properties of blended surimi from various grades can be represented as non-linear functions. Therefore, non-linear programming was found to be appropriate for determining the optimum formulation for surimi products blended from various grades of surimi. About 3.3% to 18.8% of hairtail surimi could be used when blending with high-grade surimi to produce surimi seafood.

关键词： non-linear programming optimization surimi blend

来源：评论

学校读者我要写书评

暂无评论

Internal auditor selection using a TOPSIS/non-linear programming model

引用

ANNALS OF OPERATIONS RESEARCH 2021年第1-2期296卷 513-539页

作者： Petridis, Konstantinos Drogalas, Georgios Zografidou, Eleni Univ Macedonia Dept Appl Informat Informat Syst & E Business ISeB Lab Egnatia 156 Thessaloniki 54006 Greece Univ Macedonia Dept Business Adm Egnatia 156 Thessaloniki 54006 Greece

One of the most challenging problems in personnel selection is the multi-attribute nature of the candidates. This problem is magnified during the procedure of selection of sophisticated personnel, such as internal auditors. By definition, an internal auditor must combine a selection of analytical and non-analytical skills, corresponding to specific cognitive and behavioral attributes. In this paper, a framework for internal auditors' selection using TOPSIS technique is proposed, integrating behavioral and cognitive skills. AHP technique has been used to determine the weights of each criterion. By prioritizing the latter skills, the proposed framework can identify employable and potentially employable candidates. Besides considering the desirable skills in the process of personnel selection, the expected performance is also taken into account. To examine what would be the ideal importance of cognitive and behavioral skills that maximizes candidates' performance, a non-linear programming method is applied. A real-life application is demonstrated to a sample of internal auditors from the Greek branch of a multi-national company.

关键词： Internal auditor selection Quantitative methods AHP TOPSIS non-linear programming

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：