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71.
Applying simulated annealing to location-planning models 总被引:9,自引:0,他引:9
Simulated annealing is a computational approach that simulates an annealing schedule used in producing glass and metals. Originally developed by Metropolis et al. in 1953, it has since been applied to a number of integer programming problems, including the p-median location-allocation problem. However, previously reported results by Golden and Skiscim in 1986 were less than encouraging. This article addresses the design of a simulated-annealing approach for the p-median and maximal covering location problems. This design has produced very good solutions in modest amounts of computer time. Comparisons with an interchange heuristic demonstrate that simulated annealing has potential as a solution technique for solving location-planning problems and further research should be encouraged. 相似文献
72.
我们得到了H-空间闭(开)覆盖性质的几个定理,改进和推广了Sperner,Klee,Alexandroff-Pasynkoff,Berge,Ghouila-Houri,Danzer-Grunbaum-Klee,Ky Fan,shih-Tan,Horvath和Lassonde等人的相应结果。作为应用,我们对l.c.-空间内的下半连续集值映象证明了一个几站不动点定理并且推广吉洪诺夫不动点定理到l.c. 相似文献
73.
In this paper, locating some warehouses as distribution centers (DCs) in a real-world military logistics system will be investigated. There are two objectives: finding the least number of DCs and locating them in the best possible locations. The first objective implies the minimum cost of locating the facilities and the latter expresses the quality of the DCs locations, which is evaluated by studying the value of appropriate attributes affecting the quality of a location. Quality of a location depends on a number of attributes; so the value of each location is determined by using Multi Attribute Decision Making models, by considering the feasible alternatives, the related attributes and their weights according to decision maker’s (DM) point of view. Then, regarding the obtained values and the minimum number of DCs, the two objective functions are formed. Constraints imposed on these two objectives cover all centers, which must be supported by the DCs. Using Multiple Objective Decision Making techniques, the locations of DCs are determined. In the final phase, we use a simple set partitioning model to assign each supported center to only one of the located DCs. 相似文献
74.
MartinHenk GeorgeA.Tsintsifas 《数学进展》2007,36(4):441-446
对于一个给定椭球,本文给出了它的任一全等椭球都包含一个整点的一个充分必要条件. 相似文献
75.
N. J. Wildberger 《Geometriae Dedicata》2007,128(1):145-166
One dimensional metrical geometry may be developed in either an affine or projective setting over a general field using only
algebraic ideas and quadratic forms. Some basic results of universal geometry are already present in this situation, such
as the Triple quad formula, the Triple spread formula and the Spread polynomials, which are universal analogs of the Chebyshev
polynomials of the first kind. Chromogeometry appears here, and the related metrical and algebraic properties of the projective
line are brought to the fore.
相似文献
76.
LU Zaiping WANG Changqun & XU MingyaoLMAM School of Mathematical Sciences Peking University Beijing China Department of Mathematics Zhengzhou University Zhengzhou ChinaPresent address: Department of Mathematics Qufu Normal University Qufu China. 《中国科学A辑(英文版)》2004,47(1):1-17
A graph r is said to be G-semisymmetric if it is regular and there exists a subgroup G of A := Aut(Г) acting transitively on its edge set but not on its vertex set. In the case of G. = A, we call r a semisymmetric graph. The aim of this paper is to investigate (G-)semisymmetric graphs of prime degree. We give a group-theoretical construction of such graphs, and give a classification of semisymmetric cubic graphs of order 6p2 for an odd prime p. 相似文献
77.
Several key results for set packing problems do not seem to be easily or even possibly transferable to set covering problems, although the symmetry between them. The goal of this paper is to introduce a nonidealness index by transferring the ideas used for the imperfection index defined by Gerke and McDiarmid [Graph imperfection, J. Combin. Theory Ser. B 83 (2001) 58-78]. We found a relationship between the two indices and the strength of facets defined in [M. Goemans, Worst-case comparison of valid inequalities for the TSP, mathematical programming, in: Fifth Integer Programming and Combinatorial Optimization Conference, Lecture Notes in Computer Science, vol. 1084, Vancouver, Canada, 1996, pp. 415-429; M. Goemans, L.A. Hall, The strongest facets of the acyclic subgraph polytope are unknown, in: Integer Programming and Combinatorial Optimization, Lecture Notes in Computer Science, vol. 1084, Springer, Berlin, 1996, pp. 415-429]. We prove that a clutter is as nonideal as its blocker and find some other properties that could be transferred from the imperfection index to the nonidealness index. Finally, we analyze the behavior of the nonidealness index under some clutter operations. 相似文献
78.
Ralf - Dieter Schindler 《Mathematical Logic Quarterly》1997,43(1):22-28
We show that weakly compact cardinals are the smallest large cardinals k where k+ < k+ is impossible provided 0# does not exist. We also show that if k+Kc < k+ for some k being weakly compact (where Kc is the countably complete core model below one strong cardinal), then there is a transitive set M with M ? ZFC + “there is a strong cardinal”. 相似文献
79.
Frauke M. Bleher 《Transactions of the American Mathematical Society》2002,354(10):3893-3906
In this paper, the universal deformation rings of certain modular representations of a finite group are determined. The representations under consideration are those which are associated to blocks with Klein four defect groups and whose stable endomorphisms are given by scalars. It turns out that these universal deformation rings are always subquotient rings of the group ring of a Klein four group over the ring of Witt vectors.
80.
We apply the theory of signature invariants of links in rational homology spheres to covering links of homology boundary links. From patterns and Seifert matrices of homology boundary links, we derive an explicit formula to compute signature invariants of their covering links. Using the formula, we produce fused boundary links that are positive mutants of ribbon links but are not concordant to boundary links. We also show that for any finite collection of patterns, there are homology boundary links that are not concordant to any homology boundary links admitting a pattern in the collection.