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分布式配送系统在运输时间均匀分布条件下的性能分析 总被引:1,自引:0,他引:1
本文在运输时间不确定的前提下,对分布式配送系统在两个部件和最终产品早到无限制的情形下建立了随机优化模型。我们在极小化库存费用的同时以满足定时送货要求为目标,讨论了如何确定运输提前期,并给出了敏感性分析结果。 相似文献
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Dimitris Fotakis Epameinondas Sidiropoulos 《Applied mathematics and computation》2012,218(9):5168-5180
Spatial planning is an important and complex activity. It includes land use planning and resource allocation as basic components. An abundance of papers can be found in the literature related to each one of these two aspects separately. On the contrary, a much smaller number of research reports deal with both aspects simultaneously. This paper presents an innovative evolutionary algorithm for treating combined land use planning and resource allocation problems. The new algorithm performs optimization on a cellular automaton domain, applying suitable transition rules on the individual neighbourhoods. The optimization process is multi-objective, based on non-domination criteria and self-organizing. It produces a Pareto front thus offering an advantage to the decision maker, in comparison to methods based on weighted-sum objective functions. Moreover, the present multi-objective self-organizing algorithm (MOSOA) can handle both local and global spatial constraints. A combined land use and water allocation problem is treated, in order to illustrate the cellular automaton optimization approach. Water is allocated after pumping from an aquifer, thus contributing a nonlinearity to the objective function. The problem is bi-objective aiming at (a) the minimization of soil and groundwater pollution and (b) the maximization of economic profit. An ecological and a socioeconomic constraint are imposed: (a) Groundwater levels at selected places are kept above prescribed thresholds. (b) Land use quota is predefined. MOSOA is compared to a standard multi-objective genetic algorithm and is shown to yield better results both with respect to the Pareto front and to the degree of compactness. The latter is a highly desirable feature of a land use pattern. In the land use literature, compactness is part of the objective function or of the constraints. In contrast, the present approach renders compactness as an emergent result. 相似文献
15.
《Optimization》2012,61(8):1577-1598
ABSTRACTThis paper is aimed to study a single-product multi-criteria transportation network with capacity constraints. We use a vector version of the Heaviside Step function to construct an optimization problem, the solutions of which form the set of equilibria of our model. We propose two methods to solve this problem. The first one is based on a modified Frank-Wolfe gradient algorithm, and the second one is based on smoothing the objective function, the optimal solutions of which can be obtained by optimization tools. Numerical examples are also given to illustrate our approaches. 相似文献
16.
The Pollution-Routing Problem (PRP) is a recently introduced extension of the classical Vehicle Routing Problem with Time Windows which consists of routing a number of vehicles to serve a set of customers, and determining their speed on each route segment so as to minimize a function comprising fuel, emission and driver costs. This paper presents an adaptive large neighborhood search for the PRP. Results of extensive computational experimentation confirm the efficiency of the algorithm. 相似文献
17.
Well known extensions of the classical transportation problem are obtained by including fixed costs for the production of
goods at the supply points (facility location) and/or by introducing stochastic demand, modeled by convex nonlinear costs,
at the demand points (the stochastic transportation problem, [STP]). However, the simultaneous use of concave and convex costs
is not very well treated in the literature. Economies of scale often yield concave cost functions other than fixed charges,
so in this paper we consider a problem with general concave costs at the supply points, as well as convex costs at the demand
points. The objective function can then be represented as the difference of two convex functions, and is therefore called
a d.c. function. We propose a solution method which reduces the problem to a d.c. optimization problem in a much smaller space,
then solves the latter by a branch and bound procedure in which bounding is based on solving subproblems of the form of [STP].
We prove convergence of the method and report computational tests that indicate that quite large problems can be solved efficiently.
Problems up to the size of 100 supply points and 500 demand points are solved.
Received October 11, 1993 / Revised version received July 31, 1995 Published online November 24, 1998 相似文献
18.
The identification of key nodes plays an important role in improving the robustness of the transportation network. For different types of transportation networks, the effect of the same identification method may be different. It is of practical significance to study the key nodes identification methods corresponding to various types of transportation networks. Based on the knowledge of complex networks, the metro networks and the bus networks are selected as the objects, and the key nodes are identified by the node degree identification method, the neighbor node degree identification method, the weighted k-shell degree neighborhood identification method (KSD), the degree k-shell identification method (DKS), and the degree k-shell neighborhood identification method (DKSN). Take the network efficiency and the largest connected subgraph as the effective indicators. The results show that the KSD identification method that comprehensively considers the elements has the best recognition effect and has certain practical significance. 相似文献
19.
A tabu search procedure for multicommodity location/allocation with balancing requirements 总被引:2,自引:0,他引:2
Teodor G. Crainic Michel Gendreau Patrick Soriano Michel Toulouse 《Annals of Operations Research》1993,41(4):359-383
We propose a tabu search heuristic for the location/allocation problem with balancing requirements. This problem typically arises in the context of the medium term management of a fleet of containers of multiple types, where container depots have to be selected, the assignment of customers to depots has to be established for each type of container, and the interdepot container traffic has to be planned to account for differences in supplies and demands in various zones of the geographical territory served by a container shipping company. It is modeled as a mixed integer program, which combines zero-one location variables and a multicommodity network flow structure. Extensive computational results on a set of benchmark problems and comparisons with an efficient dual ascent procedure are reported. These show that tabu search is a competitive approach for this class of problems. 相似文献
20.
钢管定购和运输的策略优化 总被引:2,自引:0,他引:2
安冉 《数学的实践与认识》2001,31(6):646-653
本文为图 1主管道和图 2树形管道的定购和运输计划给出了一个最优化模型 .通过解这一个最优化模型得到钢管的定购和运输的最优策略 .同时 ,分析了哪个钢厂钢管销价的变化对图 1主管道购运计划和总费用影响最大 ,哪个钢厂钢管产量的上限的变化对购运计划和总费用影响最大 相似文献