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AN EFFICIENT HYBRID LP-LP METHOD FOR THE OPTIMAL UTILIZATION OF CONFINED AQUIFERS

IRRIGATION AND DRAINAGE 2013年第1期62卷 120-128页

作者： Khadem, M. Afshar, M. H. Iran Univ Sci & Technol Sch Civil Engn Tehran Iran Iran Univ Sci & Technol Envirohydroinformat Ctr Excellence Tehran Iran

This paper presents an efficient hybrid methodology for solution of the groundwater management problem. The problem to be addressed is the minimization of the pumping cost of a predefined number of wells of fixed position in a two-dimensional (2D) confined aquifer. The solution of the problem is defined by the pumping rate of the wells which satisfy downstream demand, the lower/upper bound on the pumping rates, and the upper bound on the water level drawdown in the wells. This problem is one of non-linear optimization which can be solved using conventional non-linear programming (NLP) and modern heuristic algorithms with their corresponding advantages and shortcomings. In the proposed method, the problem is formulated as one of optimization in terms of pumping rates and water level drawdown in the wells by embedding the discretized version of the differential equation governing the aquifer in the problem formulation. The resulting constrained non-linear optimization problem is then decomposed into two linear optimization problems with different sets of decision variables, namely pumping rates and water level drawdown. The newly formed linear problems are solved iteratively using a simplex method leading to a highly efficient hybrid method. The ability and efficiency of the proposed method are tested against three test examples and the results presented and compared to other methods. The results indicate the superiority of the proposed method over others available in the literature such as NLP and GA in both accuracy and computational effort. While the performance of the available methods is shown to deteriorate with the size of the problem, when the number of wells to be operated are increased, the proposed method is shown to be insensitive to problem size, offering a robust method for solving real-life groundwater management problems. Copyright (c) 2012 John Wiley & Sons, Ltd.

关键词： groundwater optimization genetic algorithm linear programming non-linear programming decomposition

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Deterministic global optimization in ab-initio quantum chemistry

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JOURNAL OF GLOBAL OPTIMIZATION 2013年第2期56卷 537-558页

作者： Janes, Pete P. Rendell, Alistair P. Australian Natl Univ Res Sch Comp Sci Canberra ACT 0200 Australia

A large number of problems in ab-initio quantum chemistry involve finding the global minimum of the total system energy. These problems are traditionally solved by numerical approaches equivalent to local optimization. While these approaches are relatively efficient, they do not provide guarantees of global optimality unless a starting point sufficiently close to the global minimum is known apriori. Due to the enormous amount of computational effort required to solve these problems, more mathematically rigorous alternatives have so far received very little attention. Taking the above issue into consideration, this paper explores the use of deterministic global optimization in the context of Hartree-Fock theory, an important mathematical model applied in many quantum chemistry methods. In particular, it presents a general purpose approach for generating linear relaxations for problems arising from Hartree-Fock theory. This was then implemented as an extension to the (Convex Over and Under ENvelopes for nonlinear Estimation) branch and bound mixed integer non-linear programs solver. Proof of concept calculations that simultaneously optimise the orbital coefficients and the location of the nuclei in closed-shell Hartree-Fock calculations are presented and discussed.

关键词： Convex relaxation Deterministic global optimization Branch and bound non-linear programming Quantum chemistry Hartree-Fock

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Design of discrete Dutch auctions with an uncertain number of bidders

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ANNALS OF OPERATIONS RESEARCH 2013年第1期211卷 255-272页

作者： Li, Zhen Kuo, Ching-Chung Middle Tennessee State Univ Jones Coll Business Dept Management & Mkt Murfreesboro TN 37132 USA Univ N Texas Coll Business Dept Management Denton TX 76203 USA

The focus of this paper is on Dutch auctions where the bidding prices are restricted to a finite set of values and the number of bidders follows a Poisson distribution. The goal is to determine what the discrete bid levels should be to maximize the auctioneer's expected revenue, which is the same as the average selling price of the object under consideration. We take a new approach to the problem by formulating the descending-price competitive bidding process as a nonlinear program. The optimal solution indicates that the interval between two successive bids should be wider as the Dutch auction progresses. Moreover, the auctioneer's maximum expected revenue increases with the number of bid levels to be set as well as the expected number of bidders. Numerical examples are provided to illustrate the key results from this study and their managerial implications are discussed.

关键词： Dutch auction Discrete bid Poisson arrival Revenue maximization non-linear programming

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CONSOLIDATED AUTOMATED SUPPORT SYSTEM (CASS) EFFICIENCY AND ALLOCATION COST IMPROVEMENT

CONSOLIDATED AUTOMATED SUPPORT SYSTEM (CASS) EFFICIENCY AND ...

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作者： James L. Rorer Luis F. Asifuinagomez Naval Postgraduate School

学位级别：硕士

In this research project, we provide a method in which we incorporated a nonlinear model to allocate consolidated automated support system (CASS) stations utilizing real demand. In reviewing available literature, we frame the allocation of CASS stations as a problem of discrete capacity allocation with stochastic demand, and note that similar problems exist in the allocation of other types of service capacity (e. g., hospital beds). We employed a nonlinear model to present a better method for allocation. Currently, NAVAIR PMA 260 uses an algebraic formula to determine CASS station allocation. The nonlinear model takes into account factors that the algebraic formula does not, such as aircraft readiness and CASS station utilization. With the model, we generated an optimized allocation of CASS stations based on average demand from aircraft maintenance action forms received at a Fleet Readiness Center over a given period of time. Then, we demonstrate that the optimized allocation can account for monthly, non- stationary demand inputs, as potentially seen in a fleet response plan. Compared to the current allocation of the Fleet Readiness Center analyzed, the optimized allocation improves CASS station utilization rates with a decreased overall number of CASS stations, without an adverse change in aircraft readiness.

关键词： Consolidated automated support system CASS eCASS non-linear programming resource allocation discrete stochastic capacity allocation queuing congestion utilization operational availability readiness

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Analyzing the price skimming strategy for new product pricing

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SCIENTIA IRANICA 2013年第6期20卷 2099-2108页

作者： Shavandi, H. Zare, A. G. Sharif Univ Technol Dept Ind Engn Tehran Iran

This article presents a new model for pricing a new product considering a skimming pricing strategy in the presence of competition. We consider two periods for price setting, including skimming and an economy period. The problem is to decide on skimming as well as economy price, in order to maximize total profit. The derived model is a non-linear programming model and we have analyzed the structure and properties of an optimal solution to develop a solution method. Analytical results, as well as managerial insights, are presented by mathematical and numerical analyses. (C) 2013 Sharif University of Technology. All rights reserved.

关键词： Skimming pricing non-linear programming New product development Pricing policy Competition

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

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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

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Lower bound shakedown analysis by using the element free Galerkin method and non-linear programming

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2008年第45-48期197卷 3911-3921页

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

Shakedown analysis is a powerful tool for assessing the safety of structures under variable repeated loads. By using the element free Galerkin (EFG) method and non-linear programming, a novel numerical solution procedure is developed to perform lower bound shakedown analysis of structures made up of elastoperfectly plastic material. 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 here 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 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 the non-linear programming and determine the lower bound of shakedown load. The proposed numerical method is verified by using several numerical examples and the results show good agreement with other available solutions. (C) 2008 Elsevier B.V. All rights reserved.

关键词： shakedown analysis EFG method self-equilibrium stress reduced-basis technique non-linear programming

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

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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

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Parametric Optimization of Steel Shell Towers of High-Power Wind Turbines

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Procedia Engineering 2013年 57卷 895-905页

作者： Anatoly Perelmuter Vitalina Yurchenko SCAD Soft Ltd 3a Osvity str. 03037 Kyiv Kyiv National University of Civil Engineering and Architecture 31 Povitroflotskyj av. 03680 Kyiv

This paper presents a parametric optimization task of steel conic shell towers of wind-powered generators. The minimum weight of the steel tower has been considered as purpose function when produced capacity of the wind-powered generators has been fixed at the target level. The tower's height, diameters of the middle surface of the tower's conic shell at the base level and at a height if the wind turbine installation, thicknesses of the tower's conic shell, and also the diameter of the wind wheel were considered as design variables. The wind loads applied on steel shell tower have been presented in dependence of design variables and considered as state variables. The optimization problem formulated as non-linear programming task has been solved by improved gradient method. Optimum design decisions of the steel conic shell towers for the wind-powered generators with produced capacity of wide range have been defined. An optimum tower's height and weight in dependence of produced capacity of wind-powered generators have been plotted.

关键词： wind-powered generator steel shell tower parametric optimization non-linear programming gradient method software

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A non-linear programming Model for Funds Allocation in Software Development Projects

A Non-Linear Programming Model for Funds Allocation in Softw...

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4th International Conference on Wireless Communications, Networking and Mobile Computing

作者： Wang, Ning Wang, Lu Yang, Nannan Beijing Univ Posts & Telecommun Econ & Management Sch Beijing 100088 Peoples R China Beijing Univ Technol Coll Econ & Management Beijing Peoples R China Beijing Inst Fashion Technol Business Sch Beijing Peoples R China

ISBN: (纸本)9781424421077

In order to effectively avoid risks that might result in loss of failure in software development process, based on the experiences of software development and project management, this paper identifies 4 potential risk factors specific to software development projects which are integrated with 6 stages in software development process, and proposes a non-linear programming model to optimize funds allocation to reduce the risks. The paper provides an example to validate the effectiveness of the model.

关键词： software project development risk factors funds allocation non-linear programming K-T Condition

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