This paper is an attempt to develop a generic modeling framework that addresses tactical planning problems of flexible manufacturing systems in a coherent manner. We propose a generic 0-1 mixedintegerprogramming for...
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This paper is an attempt to develop a generic modeling framework that addresses tactical planning problems of flexible manufacturing systems in a coherent manner. We propose a generic 0-1 mixedintegerprogramming formulation, that integrates batching, loading, and routing problems with their critical aspects related to a system's performance. For this purpose, a thorough analysis is made to determine and relate system components, their attributes, and alternatives together with performance measures specific to tactical planning. This provided the justification to support our argument about generality of the model. A linear programming formulation is provided to approximate the mixedinteger formulation proposed so as to overcome the problem's combinatorial complexity. The potential capability of the linear approximation proposed also is demonstrated via a small set of test problems.
The column generation approach to large-scale linear programming is extended to the mixed-integer case. Two general algorithms, a dual and a primal one, are presented. Both involve finding k-best solutions to combinat...
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The column generation approach to large-scale linear programming is extended to the mixed-integer case. Two general algorithms, a dual and a primal one, are presented. Both involve finding k-best solutions to combinatorial optimization subproblems. Algorithms for these subproblems must be tailored to each specific application. Their use is illustrated by applying them to a new combinatorial optimization problem with applications in Artificial Intelligence: Probabilistic Maximum Satisfiability. This problem is defined as follows: consider a set of logical sentences together with probabilities that they are true, assume this set of sentences is not satisfiable in the probabilistic sense, i.e., there is no probability distribution on the set of possible worlds (truth assignments to the sentences corresponding to at least one truth assignment to the logical variables they contain) such that for each sentence the sum of probabilities of the possible worlds in which it is true is equal to its probability of being true;determine a minimum set of sentences to be deleted in order to make the remaining set of sentences satisfiable. Computational experience with both algorithms is reported on. (C) 1998 Published by Elsevier Science B.V.
This paper considers the solution of systems of algebraic equations that are expressed by a global rectangular system of equations, and a set of conditional equations that are expressed as disjunctions. These disjunct...
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This paper considers the solution of systems of algebraic equations that are expressed by a global rectangular system of equations, and a set of conditional equations that are expressed as disjunctions. These disjunctions are given by equations and inequalities, where the latter define the domain of validity of the equations. The solution of such a system is defined by variable values satisfying the rectangular equations, and exactly one set of equations for each of the disjunctions. This paper addresses first the solution of systems of linear disjunctive equations. Using a convex hull representation of each of the disjunctions, it is shown that these equations can be converted into an MILP problem. A sufficient condition is presented under which this model is shown to be solvable as an LP problem. An extension to nonlinear disjunctive equations is presented by incorporating the proposed MILP formulation within a Newton iterative scheme. The application of the proposed algorithms is illustrated with several examples, including piecewise linear mass balances in process networks, and pipe networks with different flow regimes and check valves. (C) 1998 Elsevier Science Ltd. All rights reserved.
Scheduling of a bus transit system must be formulated as an optimization problem, if the level of service to passengers is to be maximized within the available resources. In this paper, we present a formulation of a t...
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Scheduling of a bus transit system must be formulated as an optimization problem, if the level of service to passengers is to be maximized within the available resources. In this paper, we present a formulation of a transit system scheduling problem with the objective of minimizing the overall waiting time of transferring and nontransferring passengers while satisfying a number of resource- and service-related constraints. It is observed that the number of variables and constraints for even a simple transit system (a single bus station with three routes) is too large to tackle using classical mixed-integer optimization techniques. The paper shows that genetic algorithms (GAS) are ideal for these problems, mainly because they (i) naturally handle binary variables, thereby taking care of transfer decision variables, which constitute the majority of the decision variables in the transit scheduling problem;and (ii) allow procedure-based declarations, thereby allowing complex algorithmic approaches (involving if then-else conditions) to be handled easily. The paper also shows how easily the same GA procedure with minimal modifications can handle a number of other more pragmatic extensions to the simple transit scheduling problem: buses with limited capacity, buses that do not arrive exactly as per scheduled times, and a multiple-station transit system having common routes among bus stations. Simulation results show the success of GAS in all these problems and suggest the application of GAS in more complex scheduling problems.
The paper presents a mixed-integer nonlinear programming (MINLP) approach to construction and operational optimization of carbon-in-pulp (CIP) processes related to hydrometallurgical gold recovery plants. In this plan...
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A two-stage, distribution-planning problem is addressed. Customers are to be served with different commodities from a number of plants, through a number of intermediate distribution centres (DCs). The possible locatio...
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A new approach based on mixed-integer programming is proposed for daily economical operation planning problem for a multi-area system with hydro-themal plants and a pump storage plant. All generator units can be coord...
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ISBN:
(纸本)0780347544
A new approach based on mixed-integer programming is proposed for daily economical operation planning problem for a multi-area system with hydro-themal plants and a pump storage plant. All generator units can be coordinately and economically operated in order to gain the most economical effects of the whole power network. The calculation results also show that the approach proposed can successfully make use of pump storage plant to shift the peak of the load curve so that the operation condition of the whole power system can be greatly improved.
Network design is a very important issue in the area of telecommunications and computer networks, where there is a large need for construction of new networks. This is due to technological development (fiber optics fo...
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Fenchel cutting planes are based on the dual relationship between separation and optimization and can be applied in many instances where alternative cutting planes cannot. They are deep in the sense of providing the m...
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Fenchel cutting planes are based on the dual relationship between separation and optimization and can be applied in many instances where alternative cutting planes cannot. They are deep in the sense of providing the maximum separation between a point ($) over cap x and a polyhedron P as measured by an arbitrary norm which is specified in the process of generating a Fenchel cut. This paper demonstrates a number of fundamental convergence properties of Fenchel cuts and addresses the question of which norms lead to the most desirable Fenchel cuts. The strengths and weaknesses of the related class of 1-polar cuts are also examined.
Environmental integrated production and recycling planning is of great importance for the competitive position of production enterprises. Due to increasing disposal costs for industrial byproducts and waste as well as...
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Environmental integrated production and recycling planning is of great importance for the competitive position of production enterprises. Due to increasing disposal costs for industrial byproducts and waste as well as stronger emission standards. companies will be required to setup and control advanced, environmental friendly production technologies, so that emissions and byproducts will be reduced drastically. Nonavoidable byproducts and used products at the end of their lifetime have to be recycled by the producers. The complexity of the resulting decision problems requires adequate. operations research methods. The following paper deals with the development of sophisticated operations research models for two selected planning problems: recycling of industrial byproducts and dismantling and recycling of products at the end of their lifetime. The models have been applied successfully to large industrial problems in practice in the fields of recycling of demolition waste in a German-French region and byproduct management in the steel industry. The presentations of these two applications follow a case study point of view.
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