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刘春平 《数学物理学报(A辑)》2004,4(6):661-668
该文给出了一种构造非线性发展方程显式行波解的方法并用该方法得到了Hirota-Satsuma方程组,一类非线性常微分方程以及广义耦合标量场方程组的显式行波解. 相似文献
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Explicit Traveling Wave Solutions and Their Dynamical Behaviors for the Coupled Higgs Field Equation 下载免费PDF全文
In this paper, we focus on the traveling wave solutions of the coupled Higgs field equation from the perspective of dynamical systems. Through the phase portraits, in addition to periodic wave solutions and solitary wave solutions, we also obtain explicit periodic singular wave solutions, singular wave solutions and kink wave solutions, which were not found in the previous works. The dynamical behavior of these solutions and their internal relations are revealed through asymptotic analysis. The results will help supplement the study of field equation. 相似文献
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Thermodynamical approach to the traveling salesman problem: An efficient simulation algorithm 总被引:9,自引:0,他引:9
V. Černý 《Journal of Optimization Theory and Applications》1985,45(1):41-51
We present a Monte Carlo algorithm to find approximate solutions of the traveling salesman problem. The algorithm generates randomly the permutations of the stations of the traveling salesman trip, with probability depending on the length of the corresponding route. Reasoning by analogy with statistical thermodynamics, we use the probability given by the Boltzmann-Gibbs distribution. Surprisingly enough, using this simple algorithm, one can get very close to the optimal solution of the problem or even find the true optimum. We demonstrate this on several examples.We conjecture that the analogy with thermodynamics can offer a new insight into optimization problems and can suggest efficient algorithms for solving them.The author acknowledges stimulating discussions with J. Piút concerning the main ideas of the present paper. The author is also indebted to P. Brunovský, J. erný, M. Hamala, . Peko, . Znám, and R. Zajac for useful comments. 相似文献
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Christofides [1] proposes a heuristic for the traveling salesman problem that runs in polynomial time. He shows that when the graphG = (V, E) is complete and the distance matrix defines a function onV × V that is metric, then the length of the Hamiltonian cycle produced by the heuristic is always smaller than 3/2 times the length of an optimal Hamiltonian cycle. The purpose of this note is to refine Christofides' worst-case analysis by providing a tight bound for everyn 3, wheren is the number of vertices of the graph. We also show that these bounds are still tight when the metric is restricted to rectilinear distances, or to Euclidean distances for alln 6.This work was supported, in part, by NSF Grant ENG 75-00568 to Cornell University. This work was done when the authors were affiliated with the Center for Operations Research and Econometrics, University of Louvain, Belgium. 相似文献
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《Applied Mathematical Modelling》2014,38(19-20):4796-4803
We consider the computational analysis of processes within the spatially-distributed model simulating the glycolytic reaction taking place in the one-side fed open chemical reactor. The main point of the simulation is the decomposition of the reaction–diffusion system into unidirectional reaction in a bulk supplied by feedback terms stated as boundary conditions on the lower boundary of the reactor, i.e. the unique plane where an exchange with an outer medium is possible within the real experimental situation. Analysis of the curvature of the reagents distribution curves proves kinematic character of the observed lateral waves corresponding to the picture of experimentally observed glycolytic traveling waves. At the same time, their origin relates to diffusion of the reagents in a vertical cross-section of the reactor. Study of the solutions for the concerned reaction–diffusion model in the case of stochastically different diffusion coefficients reveals the Turing structures. 相似文献
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《Operations Research Letters》2019,47(3):197-201
The Traveling Salesman Problem with Pickup and Delivery seeks a minimum cost path with pickups preceding deliveries. It is important in on-demand last-mile logistics, such as ride sharing and meal delivery. We examine the use of low-width Decision Diagrams in a branch-and-bound with and without Assignment Problem inference duals as a primal heuristic for finding good solutions within strict time budgets. We show these diagrams can be more effective than similarly structured hybrid Constraint Programming techniques for real-time decision making. 相似文献
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