In this paper, a shortest route formulation of simple U-type assembly line balancing (SULB) problem is presented and illustrated on a numerical example. This model is based on the shortest route model developed in [Ma...
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In this paper, a shortest route formulation of simple U-type assembly line balancing (SULB) problem is presented and illustrated on a numerical example. This model is based on the shortest route model developed in [Manage. Sci. 11 (2) (1964) 308.] for the traditional single model assembly line balancing problem. (C) 2004 Elsevier Inc. All rights reserved.
Today, firms have to compete on international openness markets. The resulting production organisation is a multi-site production system. Several production units called sites have to supply irregular demands at the lo...
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Today, firms have to compete on international openness markets. The resulting production organisation is a multi-site production system. Several production units called sites have to supply irregular demands at the lower costs. We propose a two-level production management approach to control such systems. It results in a global multi-site production planning and in local multi-workshop scheduling. This paper focuses on the multi-site production planning problem. A primal-dual approach is proposed to solve this problem. It allows us to minimise variable and fixed costs. This heuristic has been experimented on a wide range of problem test data. (C) 2001 Elsevier Science B.V. All rights reserved.
The paper presents a computerized model for finding the single most economical landing location for ground-based timber harvesting and finding the least cost road path from the selected landing point to the existing o...
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The paper presents a computerized model for finding the single most economical landing location for ground-based timber harvesting and finding the least cost road path from the selected landing point to the existing off-road. The model uses raster-based GIS data and considers multiple design factors influencing the optimal landing location. Terrain conditions, the volume of stock distribution, downhill and uphill skidding directions, and distance to the existing road were the influencing design factors in the model. Three approaches were adopted for finding a landing location within three harvest units. In the first approach, a preliminary process evaluated all cells of a 20m x 20m network within the harvest units and determined the candidate landing cells with the largest gentle slope (<10%) area. In the second and third approaches, the points on a 50m x 50m mesh grid and the harvest units' centroids were assumed as candidate landings, respectively. The sum of skidding, road construction, and hauling costs was as total harvesting costs. Results indicated that the distance to the existing roads and the access direction from the existing road to the candidate landings could effectively limit the choice options for landing location. Results of feeding a penalized cost estimation model as an objective function to the modified Dijkstra's shortest path algorithm led to planning the road alignments with the least expected excavation and soil disturbance. Results also showed that the optimal landings could ensure the least total harvesting cost within the harvest unit.
Many algorithms and applications call for the use of a network subprogram which must be optimized numerous times with slight changes to the problem data. Bound anal right-hand-side changes to an existing basis tree ma...
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Many algorithms and applications call for the use of a network subprogram which must be optimized numerous times with slight changes to the problem data. Bound anal right-hand-side changes to an existing basis tree may yield an infeasible basic solution. This report gives a sequence of steps that modify an existing basic solution to reflect such changes and streamline the reoptimization process. [ABSTRACT FROM AUTHOR]
This paper presents integer programming models for the determination of(a) optimal sequences of wastewater treatment processes, and (b) minimum cost, energy efficient composite wall and roof structures. The first mode...
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This paper presents integer programming models for the determination of(a) optimal sequences of wastewater treatment processes, and (b) minimum cost, energy efficient composite wall and roof structures. The first model has been used to determine optimal sequences of wastewater treatment processes for a combined industrial and sanitary wastewater facility in Kuwait. The second model was used to assist design engineers in meeting government standards for the thermal resistance of building structures. Remarkably, the two models have essentially the same structure: a shortest path model with additional linear side constraints. The two practical applications are described and solved, and computational experience is discussed. (C) 1997 Elsevier Science B.V.
In this paper we work on a multi-level network optimization problem that integrates into the same model important aspects of: (i) discrete facility location, (ii) topological network design, and (iii) network dimensio...
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In this paper we work on a multi-level network optimization problem that integrates into the same model important aspects of: (i) discrete facility location, (ii) topological network design, and (iii) network dimensioning. Potential applications for the model are discussed, stressing its growing importance. The multi-level network optimization problem treated is defined and a mathematical programming formulation is presented. We make use of a branch-and-bound algorithm based on Lagrangean relaxation lower bounds to introduce some new powerful auxiliary algorithms to exactly solve the problem. We conduct a set of computational experiments that indicate the quality of the proposed approach. (C) 1999 Elsevier Science B.V. All rights reserved.
In several resource allocation problems, one encounters transportation networks which may or may not be feasible, and which may also be accompanied by side constraints. In such contexts, one typically constructs some ...
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In several resource allocation problems, one encounters transportation networks which may or may not be feasible, and which may also be accompanied by side constraints. In such contexts, one typically constructs some dummy transportation arcs with associated penalties, which either serve the role of facilitating a convenient starting solution, or seeking a solution to an infeasible problem which minimizes the total flow on the dummy arcs. In either case, particularly when the original transportation problem is infeasible, one would like to know a preferably small lower bound on the dummy arc penalties which could be validly employed. This paper derives such a bound. Extensions to more general networks are also addressed. [ABSTRACT FROM AUTHOR]
This paper introduces the maximum benefit Chinese postman problem (MBCPP) and the maximum benefit traveling salesman problem (MBTSP). For the MBCPP a benefit is realized each time a link of a directed graph is travers...
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This paper introduces the maximum benefit Chinese postman problem (MBCPP) and the maximum benefit traveling salesman problem (MBTSP). For the MBCPP a benefit is realized each time a link of a directed graph is traversed. The MBCPP relaxes the constraint of the Chinese postman problem that each link be traversed at least once and finds a tour of maximum total net benefit. For the MBTSP a benefit is derived when a node is visited and a cost is incurred when a link is traversed. The MBTSP relaxes the constraint of the traveling salesman problem that each node be visited exactly (or at least) once and finds a tour of maximum total net benefit. Both problems are formulated as linear integer programming problems. A solution algorithm is given that repeatedly solves a relaxation of the formulation as a minimum cost flow problem using a branch-and-bound procedure. Computational examples are presented.
The Multiperiod Capacitated Minimal Spanning Tree (MCMST) Problem consists of scheduling the installation of links in a network so as to connect a set of terminal nodes S = [2, 3,..., N] to a central node (node 1) wit...
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The Multiperiod Capacitated Minimal Spanning Tree (MCMST) Problem consists of scheduling the installation of links in a network so as to connect a set of terminal nodes S = [2, 3,..., N] to a central node (node 1) with minimal present value of expenditures, where link capacities limit the number of terminal nodes sharing a link. Some of the terminal nodes are active at the beginning of the planning horizon while others are activated over time. We formulate this problem as an integer programming problem. A branch exchange heuristic procedure for solving the problem is presented. We also present a Lagrangian relaxation method to find a lower bound for the optimal objective function value. This lower bound may be used to estimate the quality of the solution given by the branch exchange heuristic. Experimental results over a wide range of problem structures show that the branch exchange heuristic method yields verifiably good solutions to this problem. (C) 2000 Elsevier Science B.V. All rights reserved.
Optimal transportation theory is an area of mathematics with real-world applications in fields ranging from economics to optimal control to machine learning. We propose a new algorithm for solving discrete transport (...
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Optimal transportation theory is an area of mathematics with real-world applications in fields ranging from economics to optimal control to machine learning. We propose a new algorithm for solving discrete transport (network flow) problems, based on classical auction methods. Auction methods were originally developed as an alternative to the Hungarian method for the assignment problem, so the classic auction-based algorithms solve integer-valued optimal transport by converting such problems into assignment problems. The general transport auction method we propose works directly on real-valued transport problems. Our results prove termination, bound the transport error, and relate our algorithm to the classic algorithms of Bertsekas and Castanon.
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