共查询到20条相似文献,搜索用时 15 毫秒
1.
A. E. Eiben E. H. L. Aarts K. M. van Hee W. P. M. Nuijten 《Annals of Operations Research》1995,55(1):81-99
We present the General Search Procedure (GSP) that provides a unifying way of describing search algorithms. The GSP captures both constructive and iterative search algorithms. We demonstrate as an exercise that various well-known heuristic search procedures can be obtained as instances of the GSP. The introduced formalism provides a solid ground to prove theoretical properties of search methods. Furthermore, by the formal approach we obtain a framework that can serve as the basis of implementing a search based problem solver. 相似文献
2.
This paper presents a simple yet efficient heuristic for rectilinear Steiner routing. The basic heuristic introduces a new edge into the existing tree for another, costlier edge such that the resulting graph remains a tree. The simplicity of the heuristic led to an O(n2) implementation using basic data structures. Asymptotic time requirement of the heuristic can be further improved to O(n log n) using sophisticated data structures. Due to the generality of the heuristic different cost criteria can be applied to produce routes with different properties. The heuristic has been successfully applied to the problem of minimum-length Steiner routing and minimizing critical-sink Elmore delay. 相似文献
3.
In this paper, the nonconvex form of the weighted maxmin dispersionproblem is converted to a form involving the maximization ofconvex functions over a polytope, for which algorithms exist.A heuristic approach is given, together with associated resultson optimality and bounds on loss of optimality. 相似文献
4.
Constrained shortest path problems have many applications in areas like network routing, investments planning and project evaluation as well as in some classical combinatorial problems with high duality gaps where even obtaining feasible solutions is a difficult task in general.We present in this paper a systematic method for obtaining good feasible solutions to hard (doubly constrained) shortest path problems. The algorithm is based essentially on the concept of efficient solutions which can be obtained via parametric shortest path calculations. The computational results obtained show that the approach proposed here leads to optimal or very good near optimal solutions for all the problems studied.From a theoretical point of view, the most important contribution of the paper is the statement of a pseudopolynomial algorithm for generating the efficient solutions and, more generally, for solving the parametric shortest path problem. 相似文献
5.
This paper describes an approach to solving a real-world problem which involves the transportation of multiple types of commodities from a number of sources to a number of destinations in discrete time periods, using a capacitated heterogeneous fleet of vehicles. The preliminary objective is to minimize the total number of discrete periods needed to complete the entire operation. The problem is first formulated as a mixed integer programme and its tractability is then greatly improved by reformulating it through backward decomposition into two separate models and solved iteratively. A heuristic approach harnessing specific features of the second approach is developed for solving large size problems to obtain near-optimal solutions within reasonable time. The design of the heuristic also takes into consideration the secondary objectives of minimizing the total vehicle capacity used and minimizing the total capacity of sources needed to satisfy the demands at the destinations. Computational results are provided for a variety of randomly generated problems as well as problems from the literature. The approach described here may be applied to the multi-period transportation of personnel and goods from multiple starting points to multiple destinations in both military and civilian applications. 相似文献
6.
Nicholas V. Findler 《European Journal of Operational Research》1979,3(1):20-22
A situation paradigm is presented in which some authority wants to optimize, in the statistical sense, the decisions to be made by the individual members of a group. An incentive scheme based on rewards and penalties is proposed. The appropriate levels of the latter are initially set by experimentally found utility scales and are then continually adjusted by a learning program. 相似文献
7.
A simple approach to Hardy inequalities 总被引:3,自引:0,他引:3
E. Mitidieri 《Mathematical Notes》2000,67(4):479-486
We describe a simple method of proving Hardy-type inequalities of second and higher order with weights for functions defined
in ℝ
n
. It is shown that we can obtain such inequalities with sharp constants by applying the divergence theorem to specially chosen
vector fields. Another approach to Hardy inequalities based on the application of identities of Rellich-Pokhozhaev type is
also proposed.
Translated fromMatematicheskie Zametki, Vol. 67, No. 4, pp. 563–572, April, 2000. 相似文献
8.
Rudolf Berghammer Stefan Bolus Agnieszka Rusinowska Harrie de Swart 《European Journal of Operational Research》2011
Simple games are a powerful tool to analyze decision-making and coalition formation in social and political life. In this paper, we present relation-algebraic models of simple games and develop relational specifications for solving some basic problems of them. In particular, we test certain fundamental properties of simple games and compute specific players and coalitions. We also apply relation algebra to determine power indices. This leads to relation-algebraic specifications, which can be evaluated with the help of the BDD-based tool Rel View after a simple translation into the tool’s programming language. In order to demonstrate the visualization facilities of Rel View we consider an example of the Catalonian Parliament after the 2003 election. 相似文献
9.
This paper presents the modified ant colony optimization (MACO) based algorithm to find global optimum. Algorithm is based on that solution space of problem is restricted by the best solution of the previous iteration. Furthermore, the proposed algorithm is that variables of problem are optimized concurrently. This algorithm was tested on some standard test functions, and successful results were obtained. Its performance was compared with the other algorithms, and observed to be better. 相似文献
10.
Rough set theory has shown success in being a filter-based feature selection approach for analyzing information systems. One of its main aims is to search for a feature subset called a reduct, which preserves the classification ability of the original system. In this paper, we consider ordered decision systems, where the preference order, a fundamental concept in dominance-based rough set approach, plays a critical role. In recent literature, based on the greedy hill climbing method, many heuristic attribute reduction algorithms are proposed by utilizing significance measures of attributes, and they are extended to deal with ordered decision systems. Unfortunately, they are often time-consuming, especially when applied to deal with large scale data sets with high dimensions. To reduce the complexity, a novel accelerator is introduced in heuristic algorithms from the perspectives of objects and criteria. Based on the new accelerator, the number of objects and the dimension of criteria are lessened thus making the accelerated algorithms faster than their original counterparts while maintaining the same reducts. Experimental analysis shows the validity and efficiency of the proposed methods. 相似文献
11.
K Y Huang 《The Journal of the Operational Research Society》2012,63(9):1248-1257
A classification method, which comprises Fuzzy C-Means method, a modified form of the Huang-index function and Variable Precision Rough Set (VPRS) theory, is proposed for classifying labeled/unlabeled data sets in this study. This proposed method, designated as the MVPRS-index method, is used to partition the values of per conditional attribute within the data set and to achieve both the optimal number of clusters and the optimal accuracy of VPRS classification. The validity of the proposed approach is confirmed by comparing the classification results obtained from the MVPRS-index method for UCI data sets and a typical stock market data set with those obtained from the supervised neural networks classification method. Overall, the results show that the MVPRS-index method could be applied to data sets not only with labeled information but also with unlabeled information, and therefore provides a more reliable basis for the extraction of decision-making rules of labeled/unlabeled datasets. 相似文献
12.
Linear programming (LP) is the core model of constrained optimization. The Simplex method (Simplex in short) has been proven in practice to perform very well in small- or medium-sized LP problems. A new algorithm called the direct cosine Simplex algorithm (DCA) is presented here to improve upon Simplex and to solve LP problems. The proposed DCA implements a specific cosine criterion to choose the entering variable instead of the traditional most negative rule used in Simplex. Three examples are given to illustrate the implementation of the proposed DCA to improve Simplex and to serve as the optimization tool. The utility of the proposed approach is evident from the extensive computational results on test problems adapted from NETLIB. DCA reduced the number of iterations of Simplex in most cases in our computational experiment. Preliminary results for medium-sized problems are encouraging. 相似文献
13.
A practically important problem is the design of finite buffers in order to achieve a prespecified loss probability. For the class of multi-server queues with batch Poisson input this paper proposes a simple approximation using only the first two moments of the service time. Numerical investigations indicate an excellent performance of the approximation. 相似文献
14.
Michel Povlovitsch Seixas André Bergsten Mendes Marcos Ribeiro Pereira Barretto Claudio Barbieri da Cunha Marco Antonio Brinati Roberto Edward Cruz Yue Wu Philip A Wilson 《The Journal of the Operational Research Society》2016,67(1):148-158
This paper addresses a practical problem encountered in the oil industry, related to the supplying of general cargo to offshore rigs and production units. For a given route assigned to a supply vessel we seek to determine the optimal two-dimensional positioning of deck cargoes such that the overall profit is maximized, while ensuring that several safety and operational constraints are respected. In terms of mathematical modelling, the resulting problem can be seen as a rich variation of the two-dimensional knapsack problem, since some cargoes may wait for a later trip. Furthermore, given that the trip may serve many offshore units and that a substantial number of items must also return from these units, the problem becomes even more complex and can be viewed as a pickup and delivery allocation problem. We propose a probabilistic constructive procedure combined with a local search heuristic to solve this problem. We also report the results of computational experiments with randomly generated instances. These results evidence that our proposed heuristic can effectively help ship planners when dealing with such large-scale allocation problems, with many operational constraints. 相似文献
15.
In this paper, we couple the iteration method with the perturbation method to solve the well-known Blasius equation. The obtained approximate analytic solutions are valid for the whole solution domain. Comparison with Howarth’s numerical solution reveals that the proposed method is of high accuracy, the first iteration step leads to 6.8% accuracy, and the second iteration step yields the 0.73% accuracy of initial slop. 相似文献
16.
Rajiv D. Banker 《European Journal of Operational Research》1980,5(4):262-266
Correspondence with a new mathematical programming definition for efficiency as proposed by Charnes, Cooper and Rhodes (CCR) is established by means of game theoretical models. Contact with all of the CCR results is also maintained so that their results extend to our new game theoretic interpretations. The latter proceeds by means of a family of games related to a linear programming problem. The games-to-programming relations which we establish also open new possibilities for further relations between families of games and linear programs. 相似文献
17.
A new heuristic approach is presented for scheduling economic lots in a multi-product single-machine environment. Given a pre-defined master sequence of product setups, an integer linear programming formulation is developed which finds an optimal subsequence and optimal economic lots. The model takes explicit account of initial inventories, setup times and allows setups to be scheduled at arbitrary epochs in continuous time, rather than restricting setups to a discrete time grid. We approximate the objective function of the model and solve to obtain an optimal capacity feasible schedule for the approximate objective. The approach was tested on a set of randomly generated problems, generating solutions that are on average 2.5% above a lower bound on the optimal cost. We also extend the approach to allow shortages. 相似文献
18.
The Euclidean p-median problem is concerned with the decision of the locations for public service centres. Existing methods for the planar Euclidean p-median problems are capable of efficiently solving problems of relatively small scale. This paper proposes two new heuristic algorithms aiming at problems of large scale. Firstly, to reflect the different degrees of proximity to optimality, a new kind of local optimum called level-m optimum is defined. For a level-m optimum of a p-median problem, where m<p, each of its subsets containing m of the p partitions is a global optimum of the corresponding m-median subproblem. Starting from a conventional local optimum, the first new algorithm efficiently improves it to a level-2 optimum by applying an existing exact algorithm for solving the 2-median problem. The second new algorithm further improves it to a level-3 optimum by applying a new exact algorithm for solving the 3-median problem. Comparison based on experimental results confirms that the proposed algorithms are superior to the existing heuristics, especially in terms of solution quality. 相似文献
19.
Jonas Mockus 《Journal of Global Optimization》2002,22(1-4):191-203
The traditional numerical analysis considers optimization algorithms which guarantee some accuracy for all functions to be optimized. This includes the exact algorithms. Limiting the maximal error requires a computational effort that in many cases increases exponentially with the size of the problem (Horst and Pardalos, 1995, Handbook of Global Optimization, Kluwer). That limits practical applications of the worst case analysis. An alternative is the average case analysis where the average error is made as small as possible (Calvin and Glynn, 1997, J. Appl. Prob., 32: 157). The average is taken over a set of functions to be optimized. The average case analysis is called the Bayesian Approach (BA) (Diaconis, 1988, Statistical Decision Theory and Related Topics, Springer; Mockus and Mockus, 1987, Theory of Optimal Decisions, Nauk, Lithuania). Application of BA to optimization of heuristics is called the Bayesian Heuristic Approach (BHA) (Mockus, 2000, A Set of Examples of Global and Discrete Optimization, Kluwer). In this paper a short presentation of the basic ideas of BHA (described in detail in Mockus (1989), Bayesian Approach to Global Optimization, Kluwer and Mockus (2000), A Set of Examples of Global and Discrete Optimization, Kluwer) is given using the knapsack problem as an example. The application potential is illustrated by the school scheduling example. In addition the new heuristic algorithm for solving a bimatrix game problem is investigated. The results ae applied while solving real life optimization problems and also as examples for distance graduate level studies of the theory of games and markets in the Internet environment. 相似文献
20.
This paper proposes a simple heuristic that generates a solution for echelon (r,nQ,T) policies by sequentially solving a deterministic demand problem, a subproblem with fixed reorder intervals, and a subproblem with fixed batch sizes. For each of these problems, we further simplify the computation by solving a series of single-stage systems whose parameters are obtained directly from the original problem data. In a numerical study, we find that this heuristic outperforms an existing one in the literature. 相似文献