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The primary purpose of this paper is to validate a clustering procedure used to construct contiguous vehicle routing zones (VRZs) in metropolitan regions. Given a set of customers with random demand for pickups and deliveries over the day, the goal of the design problem is to cluster the customers into zones that can be serviced by a single vehicle. Monte Carlo simulation is used to determine the feasibility of the zones with respect to package count and tour time. For each replication, a separate probabilistic traveling salesman problem (TSP) is solved for each zone. For the case where deliveries must precede pickups, a heuristic approach to the TSP is developed and evaluated, also using Monte Carlo simulation. In the testing, performance is measured by overall travel costs and the probability of constraint violations. Gaps in tour length, tour time and tour cost are the measure used when comparing exact and heuristic TSP solutions. 相似文献
124.
为了求得非线性优化问题的最优解,必须从收敛的可能性和收敛速度入手实现有效的计算方法.为此,通过改变作为搜索方向的下降方向,并适当修订信赖范围,在信赖域算法的基础上提出了一种修订的最优化问题的求解方法.计算方法的计算程序虽然有些复杂,但从整体收敛性和计算可行性方面来说是一个有效的方法. 相似文献
125.
V. A. Smirnov 《Mathematical Notes》1999,65(2):221-229
A construction of Dyer-Lashof operations for cobordisms of topological spaces is presented.
Translated fromMatematicheskie Zametki, Vol. 65, No. 2, pp. 270–279, February, 1999. 相似文献
126.
Khaled F. Abdelghany Ahmed F. Abdelghany Goutham Ekollu 《European Journal of Operational Research》2008
This paper presents a decision support tool for airlines schedule recovery during irregular operations. The tool provides airlines control centers with the capability to develop a proactive schedule recovery plan that integrates all flight resources. A rolling horizon modeling framework, which integrates a schedule simulation model and a resource assignment optimization model, is adopted for this tool. The schedule simulation model projects the list of disrupted flights in the system as function of the severity of anticipated disruptions. The optimization model examines possible resource swapping and flight re-quoting to generate an efficient schedule recovery plan that minimizes flight delays and cancellations. A detailed example that illustrates the application of the tool to recover the schedule of a major US air-carrier during a hypothetical ground delay program scenario is presented. The results of several experiments that illustrates overall model performance in terms of solution quality and computation experience are also given. 相似文献
127.
Alessandro?AgnetisEmail author Paolo?Detti Carlo?Meloni 《4OR: A Quarterly Journal of Operations Research》2003,1(2):103-119
This paper addresses a coordination problem concerning two production agents in a manufacturing system. The two agents have a set of processes which must be carried out on some common resource. They can use the resource individually, but in general there may be an overall advantage in concurrently performing certain processes. The problem is to select concurrent processes and to sequence them with the aim of minimizing the total number of set-ups. In particular, a decomposition approach is proposed, in which first the concurrent processes are selected, by solving a generalized network flow problem, and then an optimal process sequencing is efficiently found.AMS classification:
05C85, 90B10, 05C45Paper previously processed by Francesco Archetti for Ricerca Operativa 相似文献
128.
Florence Lecomte 《K-Theory》1998,13(2):179-207
Following Schechtman's work on deloopings of Adams operations, we show that rational Quillen K-theory of schemes defines a special ring for schemes which are quasi-projective over an affine regular base. 相似文献
129.
Jiří Pik 《Annals of Operations Research》1994,51(7):367-374
A decision support system for the analysis and forecasting of natural discrete-event processes is considered. The corresponding method is based on the sample path analysis using event-to-event operations. An application of the method in the computer-aided decision support system for the long-range weather forecasting is mentioned. 相似文献
130.
胡建军 《浙江大学学报(理学版)》2013,40(5):539-542
选择适当的椭圆曲线,对于快速部署和实现椭圆曲线密码系统具有重要的意义.由于Hessian形式的椭圆曲线可以运用并行算法快速实现点加和倍点运算,因此能够有效提高系统的实现效率.利用Hessian曲线上点的优良性质,简化了直线斜率的计算公式,优化了在Hessian曲线上计算Tate双线性对的算法.在其他运算量保持不变的前提下,改进后的算法使点加和倍乘运算的运算量分别降低13.43%和11.25%. 相似文献