The fixed channel assignment problem (CAP) is formulated as an integer linear programming problem with compatibility and requirement constraints. The proposed formulation is general and has been extended for the case ...
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The fixed channel assignment problem (CAP) is formulated as an integer linear programming problem with compatibility and requirement constraints. The proposed formulation is general and has been extended for the case of maximum packing fixed channel assignment problems. For the solution of the resulting formulation a special branch and bound algorithm has been used. The exploitation of the problem's special structure can improve the computational efficiency of the algorithm used. The model has been applied to a number of different benchmark problems that have appeared in the literature. The examples presented show that using the proposed formulation and a specially designed branch and bound algorithm, it is possible to solve optimally and efficiently fairly large channel assignment problems.
This paper analyzes the performances of parallel branch and bound algorithm with best-first search strategy by examining various anomalies on the expected speed up: detrimental, acceleration and detrimental accelerati...
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This paper analyzes the performances of parallel branch and bound algorithm with best-first search strategy by examining various anomalies on the expected speed up: detrimental, acceleration and detrimental acceleration. Since the best evaluation is not always sufficient to distinguish the best node to choose with best-first search strategy, we define tie breaking rules for cases when nodes have the same value: the fifo, the lifo and the consistent rules. The purpose of the paper is to convey, through bounds of the parallel execution for each tie breaking rule, an understanding of the nature of the anomalies, the range of their impact and a comparison of their efficiency to cope with these anomalies. Sufficient and necessary conditions are given regarding the predisposition for each of the three classes of anomalous behavior. For comparison, we introduce a propriety of proneness to anomaly. In particular, we show that the consistent rule on best-first search branch and bound algorithm may be the weaker solution to cope the detrimental acceleration anomaly. Finally, we prove that the fifo rule is theoretically and practically efficient.
Loading problems in flexible manufacturing systems involve assigning operations for selected part types and their associated tools to machines or machine groups. One of the objectives might be to maximize the expected...
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In this paper, an effective and efficient algorithm for finding the optimal morphological erosion filter on binary images is proposed. The design of morphological erosion filter is based on statistical method by minim...
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In this paper, an effective and efficient algorithm for finding the optimal morphological erosion filter on binary images is proposed. The design of morphological erosion filter is based on statistical method by minimizing mean square error. Traditionally, finding optimal morphological erosion filters requires searching through a large number of structuring-element combinations which is a long search and time consuming procedure. In the proposed method, the problem of finding the optimal solution is reduced to the problem of searching a minimal path on the error code graph (EGG). Since the graph satisfies some greedy criteria, only few nodes need to be traversed and examined. Experiments are conducted to illustrate the validity of our proposed method.
We study the single-machine scheduling problem with release and delivery times in which the set of jobs to be scheduled consists of job families requiring a machine setup between two consecutively scheduled jobs from ...
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We study the single-machine scheduling problem with release and delivery times in which the set of jobs to be scheduled consists of job families requiring a machine setup between two consecutively scheduled jobs from two different families. The setup time depends only on the family to be sequenced next, and the objective is to minimize the makespan. For the case where all the jobs of each family have to be scheduled contiguously, called the family sequencing problem, a generalization of the extended Jackson's rule is introduced and its properties are analyzed. As a result, a branch and bound algorithm is developed which is capable of solving problem instances with hundreds of jobs in very short time. Results of computational experiments are reported. For the problem with families divisible into batches, several heuristics are proposed and analyzed. The general approach consists in successively applying one of the family sequencing algorithms, heuristic or exact, to the set of batches,each lime modifying the current partition of families. Results of the worst-case analysis and computational experiments are shown.
The problem of scheduling n jobs on m machines with each job having a specific route has been one of considerable research over the last several decades. branch and bound algorithms for determining the optimal makespa...
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The problem of scheduling n jobs on m machines with each job having a specific route has been one of considerable research over the last several decades. branch and bound algorithms for determining the optimal makespan have been developed and tested on small sized problems and dispatching rule based heuristic algorithms to minimize specific performance measures such as makespan, flowtime, tardiness, etc, are available to solve large sized problems. This paper addresses the same problem faced by an organization and reports the solution of this problem using genetic algorithms (GA) and a combination of dispatching rules. The proposed algorithm yields an improvement of about 30% in makespan over the present system.
Mixtures with a known range of possibly present species can be simultaneously analysed qualitatively and quantitatively by using the branch and bound algorithm. The computation time is much less than in the enumeratio...
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Mixtures with a known range of possibly present species can be simultaneously analysed qualitatively and quantitatively by using the branch and bound algorithm. The computation time is much less than in the enumeration procedure and there is no risk of missing the real combination of co-existing components in the sample. Nitrophenol mixtures were analysed satisfactorily.
A methodology for structural synthesis is presented in which the optimal material selection for the truss structures is treated in terms of (0, 1) variables. Structural member sizes and material selection variables ar...
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A methodology for structural synthesis is presented in which the optimal material selection for the truss structures is treated in terms of (0, 1) variables. Structural member sizes and material selection variables are treated simultaneously as design variables. Optimization is carried out by generating and solving a sequence of explicit approximate problems using a branch and bound strategy. Intermediate design variables and intermediate response quantities are used to enhance the quality of the approximate design problems. Numerical results for example problems are presented to illustrate the efficiency of the design procedure set forth.
Synthetic pigments in food can be simultaneously analysed qualitatively and quantitatively by using a spectrophotometric method combined with the branch and bound algorithm. This method does not require a preseparatio...
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Synthetic pigments in food can be simultaneously analysed qualitatively and quantitatively by using a spectrophotometric method combined with the branch and bound algorithm. This method does not require a preseparation of the pigments and the relative error for each component in mixed samples was less than 5%. Candy, jelly and soft drinks were analysed satisfactorily.
The use of a genetic algorithm to optimize the stacking sequence of a composite laminate for buckling load maximization is studied. Various genetic parameters including the population size, the probability of mutation...
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The use of a genetic algorithm to optimize the stacking sequence of a composite laminate for buckling load maximization is studied. Various genetic parameters including the population size, the probability of mutation, and the probability of crossover are optimized by numerical experiments. A new genetic operator-permutation-is proposed and shown to be effective in reducing the cost of the genetic search. Results are obtained for a graphite-epoxy plate, first when only the buckling load is considered, and then when constraints on ply contiguity and strain failure are added. The influence on the genetic search of the penalty parameter enforcing the contiguity constraint is studied. The advantage of the genetic algorithm in producing several near-optimal designs is discussed.
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