We consider a generalization of the knapsack problem in which items are partitioned into classes, each characterized by a fixed cost and capacity. We study three alternative Integer Linear Programming formulations. Fo...
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We consider a generalization of the knapsack problem in which items are partitioned into classes, each characterized by a fixed cost and capacity. We study three alternative Integer Linear Programming formulations. For each formulation, we design an efficient algorithm to compute the linear programming relaxation (one of which is based on Column Generation techniques). We theoretically compare the strength of the relaxations and derive specific results for a relevant case arising in benchmark instances from the literature. Finally, we embed the algorithms above into a unified implicit enumeration scheme which is run in parallel with an improved Dynamic Programming algorithm to effectively solve the problem to proven optimality. An extensive computational analysis shows that our new exact algorithm is capable of efficiently solving all the instances of the literature and turns out to be the best algorithm for instances with a low number of classes. (C) 2017 Elsevier Ltd. All rights reserved.
Two splitting-domain algorithms using interval analysis to analyse and optimise a scalar criterion that depends non-linearly on a parameter vector are presented. Their results are guaranteed, and provided with an esti...
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Two splitting-domain algorithms using interval analysis to analyse and optimise a scalar criterion that depends non-linearly on a parameter vector are presented. Their results are guaranteed, and provided with an estimation of their degree of approximation. As an example of application, the stability degree of linear time-invariant parametric systems is considered. It is thus possible to characterise isodegrees in the parameter space and to compute a set guaranteed to contain all values of the parameters that maximise (or minimise) the stability degree as well as an interval guaranteed to contain its optimal value. Several examples of the literature illustrate the efficiency of the method.
The problem of minimizing the cost due to talent hold days in the production of a feature film is considered. A combinatorial model is developed for the sequencing of shooting days in a film shoot. The problem is show...
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The problem of minimizing the cost due to talent hold days in the production of a feature film is considered. A combinatorial model is developed for the sequencing of shooting days in a film shoot. The problem is shown to be strongly NP-hard. A branch-and-bound solution algorithm and a heuristic solution method for large instances of the problem (15 shooting days or more) are developed and implemented on a computer. A number of randomly generated problem instances are solved to study the power and speed of the algorithms. The computational results reveal that the heuristic solution method is effective and efficient in obtaining near-optimal solutions.
This article presents an algorithm for globally solving a sum of ratios fractional programming problem. To solve this problem, the algorithm globally solves an equivalent concave minimization problem via a branch-and-...
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This article presents an algorithm for globally solving a sum of ratios fractional programming problem. To solve this problem, the algorithm globally solves an equivalent concave minimization problem via a branch-and-bound search. The main work of the algorithm involves solving a sequence of convex programming problems that differ only in their objective function coefficients. Therefore, to solve efficiently these convex programming problems, an optimal solution to one problem can potentially be used to good advantage as a starting solution to the next problem.
This article presents a branch-and-bound algorithm for globally solving the problem (P) of maximizing a generalized concave multiplicative function over a compact convex set. Since problem (P) does not seem to have be...
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This article presents a branch-and-bound algorithm for globally solving the problem (P) of maximizing a generalized concave multiplicative function over a compact convex set. Since problem (P) does not seem to have been studied previously, the algorithm is apparently the first algorithm to be proposed for solving this problem. It works by globally solving a problem (P1) equivalent to problem (P). The branch-and-bound search undertaken by the algorithm uses rectangular partitioning and takes place in a space which typically has a much smaller dimension than the space to which the decision variables of problem (P) belong. Convergence of the algorithm is shown;computational considerations and benefits for users of the algorithm are given. A sample problem is also solved.
An efficient optimization algorithm for identifying the best least squares regression model under the condition of non-negative coefficients is proposed. The algorithm exposits an innovative solution via the unrestric...
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An efficient optimization algorithm for identifying the best least squares regression model under the condition of non-negative coefficients is proposed. The algorithm exposits an innovative solution via the unrestricted least squares and is based on the regression tree and branch-and-bound techniques for computing the best subset regression. The aim is to filling a gap in computationally tractable solutions to the non-negative least squares problem and model selection. The proposed method is illustrated with a real dataset. Experimental results on real and artificial random datasets confirm the computational efficacy of the new strategy and demonstrates its ability to solve large model selection problems that are subject to non-negativity constrains.
This paper considers the constrained two-dimensional cutting stock problem. Some properties of the problem are derived leading to the development of a new algorithm, which uses a very efficient branching strategy for ...
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This paper considers the constrained two-dimensional cutting stock problem. Some properties of the problem are derived leading to the development of a new algorithm, which uses a very efficient branching strategy for the solution of this problem. This strategy enables the early rejection of partial solutions that cannot lead to optimality. Computational results are given and compared with those produced by a leading alternative method. These results show that the new algorithm is far superior in terms of the computer time needed to solve such problems. International Federation of Operational Research Societies 2001.
This paper proposes two new algorithms for inference in credal networks. These algorithms enable probability intervals to be obtained for the states of a given query variable. The first algorithm is approximate and us...
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This paper proposes two new algorithms for inference in credal networks. These algorithms enable probability intervals to be obtained for the states of a given query variable. The first algorithm is approximate and uses the hill-climbing technique in the Shenoy-Shafer architecture to propagate in join trees;the second is exact and is a modification of Rocha and Cozman's branch-and-bound algorithm, but applied to general directed acyclic graphs.
In this article we present branch-and-bound algorithms for the access point assignment problem in WLANs, when the objective function is based on the throughput of stations in the network. We consider: a) maximizing th...
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ISBN:
(纸本)9781424431212
In this article we present branch-and-bound algorithms for the access point assignment problem in WLANs, when the objective function is based on the throughput of stations in the network. We consider: a) maximizing the aggregate throughput, b) achieving lexicographically max-min fair throughputs, c) achieving proportionally fair throughputs. The performance of all branch-and-bound algorithms is examined for various degrees of approximation. Thus we show trade-offs between the increased cost of exploration and improvement in the objective value. We further compare their performance to that of greedy algorithms, embedded as a depth-first-search in the branch-and-bound methods. An omnipresent result is the near-optimal performance of the greedy algorithms, which is particularly important when considering their practical application. In all cases, the performance of the algorithms improves as the distribution of wireless stations becomes more concentrated in areas of the network, as in hotspot topologies.
The robust detection of lines and arcs in scanned documents or technical drawings is an important problem in document image understanding. We present a new solution to this problem that works directly on run-length en...
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ISBN:
(纸本)3540347119
The robust detection of lines and arcs in scanned documents or technical drawings is an important problem in document image understanding. We present a new solution to this problem that works directly on run-length encoded data. The method finds globally optimal solutions to parameterized thick line and are models. Line thickness is part of the model and directly used during the matching process. Unlike previous approaches, it does not require any thinning or other preprocessing steps, no computation of the line adjacency graphs, and no heuristics. Furthermore, the only search-related parameter that needs to be specified is the desired numerical accuracy of the solution. The method is based on a branch-and-bound approach for the globally optimal detection of these geometric primitives using runs of black pixels in a bi-level image. We present qualitative and quantitative results of the algorithm on images used in the 2003 and 2005 GREC arc segmentation contests.
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