车辆路径问题（VRP）算法研究

车辆路径问题（VRP）是图论中的NP问题,目前求解这类问题的算法可分为：精确算法、经典启发式算法和现代启发式算法三类;对这三类算法中最具代表性的几种算法进行了分析指出了其适用范围和场合、存在的问题以及改进的方案;最后,对其研究前景进行了展望。     

车辆路径问题(VRP)算法研究

车辆路径问题(VRP)是图论中的NP问题,目前求解这类问题的算法可分为:精确算法、经典启发式算法和现代启发式算法三类;对这三类算法中最具代表性的几种算法进行了分析指出了其适用范围和场合、存在的问题以及改进的方案;最后,对其研究前景进行了展望。     

基于启发式带时间窗的车辆路径规划问题求解

车辆路径规划问题广泛地存在于现代物流行业中,该问题属于NP难的组合优化问题.随着客户需求的多样化、道路限行等因素的影响,该问题变得更加的复杂,采用传统的组合优化方法和运筹学方法往往难以求解.本文对一类常见的带时间窗的车辆路径规划问题进行了研究,根据时间窗参数来调整客户的优先级,以减少车辆的等待时间,由此改进了几个常见的启发式算法,并对56个常见的车辆路径规划问题进行了测试,实验结果表明,改进的节约算法在带容量约束的车辆路径问题中效果较好,改进的插入法则在带时间窗的车辆路径问题中具有优越性,另外,改进的启发式算法在4个测试用例上使用更多车辆时可使总路程优于已知最优值.     

车辆路径问题模型及其智能启发式算法

车辆路径问题是运筹学研究的一个重要分支。描述了 6种典型的车辆路径问题的模型 ,并列举了当前的 9种启发式算法     

双层车辆路径问题的混合启发式算法

针对与城市物流密切相关的双层车辆路径问题(2E-VRP),提出了一种用来求解的混合启发式算法.该算法利用贪心算法的快速性、蚁群算法的搜索多样性以及邻域搜索算法较强的局部寻优能力来提高求解质量,加速算法的收敛性.把该算法应用于22个测试算例和3个大规模的算例,并与同类研究进行了比较.实验结果表明,混合启发式算法不仅能保证较高的精确性,而且具有很高的效率;与精确性最高的同类算法相比,虽然在解的质量方面稍逊,但在求解速度方面表现出了明显的优势.实验结果还显示了构建双层城市物流系统的潜在收益,中转站的设置能够在一定条件下显著提高城市物流效率.     

变邻域搜索算法综述

变邻域搜索算法(Variable Neighborhood Search,VNS)作为一种新的元启发式算法,已初步成功地用于解决优化问题,尤其是对于大规模组合优化问题效果良好。对VNS的扩展研究层出不穷,并将其成功地应用到旅行商问题、车辆路径问题、调度、图着色等问题中。简述了经典的元启发式算法,并依次论述了优化问题,VNS算法起源,VNS算法原理,VNS算法分析,扩展的VNS分析,VNS在初始解构造、邻域结构构造、局部搜索和停止准则几个方面的改进方法,针对不同版本的VNS归纳了其在各种优化问题应用情况。基于对改进的VNS的分类,从算法自身研究角度和实际应用角度提出了未来研究方向。     

C-W算法在配送车辆优化调度中的应用

物流配送车辆优化调度是物流配送中非常关键的一个环节。文章简单介绍了当前最具有代表性的算法,指出目前启发式算法是求解车辆路径问题的主要方法,并以C-W算法为典型,结合实例验证了其对解决配送车辆调度问题的适用性。     

基于启发式蚁群算法的VRP问题研究

针对蚁群算法求解VRP问题时收敛速度慢,求解质量不高的缺点,把城市和仓库间的距离矩阵和路径节约矩阵信息融入到初始信息素矩阵中作为启发式信息引入到蚁群算法中用于求解有容量限制的车辆路径规划问题（CVRP）,在三个基准数据集上的实验研究表明,基于启发式信息的蚁群算法与基本蚁群算法相比能够以较快的速度收敛到较好的解。     

一种基于Voronoi图求解车辆路径问题的混合启发式算法

针对由多个配送中心和多个客户点组成的物流网络中的车辆路径问题,提出了一种基于“集群第一,路线第二”的路径优化策略,即首先使用Voronoi分割对配送区域进行划分,然后引入综合插入算法和变邻域搜索算法的混合启发式算法求解配送区域内车辆路径问题。通过算例和应用系统的分析与验证表明,该混合算法既能获取质量较优解,同时也具有较好的实时性,能较好地满足实际应用需求。     

三阶段优化算法求解带三维装载约束的MDVRP北大核心CSCD

对带三维装载约束的多车场车辆路径问题,以最小化车辆行驶总里程为优化目标,建立问题模型,并提出一种三阶段优化算法进行求解。第一阶段设计带循环平衡的K-medoids聚类算法,将原问题分解成多个带三维装载约束限制的车辆路径子问题。第二阶段提出一种双层结构的超启发式蚁群算法用于求解各子问题,以确定各车辆的配送路径。在该算法中,低层设计9种启发式操作,并将其所构成的排列作为高层个体;同时,高层采用蚁群算法更新高层个体,以引导算法搜索方向。第三阶段以第二阶段所得阶段解作为初始解,设计组合启发式装箱算法对带容积约束的装箱过程进行优化,进而将第二、三阶段确定的解合并为原问题的解。最后,仿真实验和算法比较验证了所提算法的有效性。     

A simple and effective evolutionary algorithm for the vehicle routing problem

The vehicle routing problem (VRP) plays a central role in the optimization of distribution networks. Since some classical instances with 75 nodes resist the best exact solution methods, most researchers concentrate on metaheuristics for solving real-life problems. Contrary to the VRP with time windows, no genetic algorithm (GA) can compete with the powerful tabu search (TS) methods designed for the VRP. This paper bridges the gap by presenting a relatively simple but effective hybrid GA. In terms of average solution cost, this algorithm outperforms most published TS heuristics on the 14 classical Christofides instances and becomes the best solution method for the 20 large-scale instances generated by Golden et al.Scope and purposeThe framework of this research is the development of effective metaheuristics for hard combinatorial optimization problems met in vehicle routing. It is surprising to notice in the literature the absence of effective genetic algorithms (GA) for the vehicle routing problem (VRP, the main capacitated node routing problem), contrary to node routing problems with time windows or arc routing problems. Earlier attempts were based on chromosomes with trip delimiters and needed a repair procedure to get feasible children after each crossover. Such procedures are known to weaken the genetic transmission of information from parents to children. This paper proposes a GA without trip delimiters, hybridized with a local search procedure. At any time, a chromosome can be converted into an optimal VRP solution (subject to chromosome sequence), thanks to a special splitting procedure. This design choice avoids repair procedures and enables the use of classical crossovers like OX. The resulting algorithm is flexible, relatively simple, and very effective when applied to two sets of standard benchmark instances ranging from 50 to 483 customers.     

多配送中心车辆路径问题的狼群算法

针对多配送中心动态启用和车辆的合理分配,文章首先建立了以总路径长度最小为目标函数的多配送中心车辆路径问题的数学模型;其次,根据多配送中心车辆路径问题的具体特征,模拟狼群捕食行为设计了求解该问题的狼群算法;最后,应用狼群算法求解测试算例,并将其计算结果与几种常见智能优化算法的计算结果进行比较,验证了狼群算法求解多配送中心车辆路径问题的可行性与有效性。     

平衡装载约束下的车辆路径问题研究

针对车辆三维装载约束下的车辆路径问题（3L-VRP）进行研究,引进车辆的平衡装载约束,综合考虑传统的先进后出、局部支撑、脆弱性等约束,构建平衡装载约束下的车辆路径问题（BL-VRP）模型。针对模型中的平衡约束,提出一种接触面积的装载算法。在此基础上,构建以回溯遗传算法（B-GA）为骨架的多阶段算法框架,对车辆路径优化进行求解。研究结果表明,多阶段算法不仅在解决3L-VRP上好于目前已有算法,同时对BL-VRP表现优秀。提出的多阶段算法为解决BL-VRP问题提供一条参考思路,但在时效性上需要进一步完善。     

融合可行基规则的粒子群优化算法及其应用

基本粒子群优化算法对于离散的优化问题处理不佳,容易陷入局部最优。针对基本粒子群优化算法处理离散型优化问题时的缺陷,提出了一种融合可行基规则的改进型粒子群优化算法,并用该算法求解车辆路径问题。实验结果表明,该算法的优化性能和求解精度均优于其他文献算法,在求解车辆路径问题中具有较高的应用价值。     

有时间窗车辆路径问题的捕食搜索算法

有时间窗车辆路径问题是当前物流配送系统研究中的热点问题,该问题具有NP难性质。难以求得最优解或满意解,在建立有时间窗车辆路径问题数学模型的基础上。设计了一种模仿动物捕食策略的捕食搜索算法．该算法利用控制搜索空间的限制大小来实现算法的局域搜索和全局搜索,具有良好的局部集中搜索和跳出局部最优的能力．通过实例计算,并与相关启发式算法比较．取得了满意的结果．     

Two memetic algorithms for heterogeneous fleet vehicle routing problems

The vehicle routing problem (VRP) plays an important role in the distribution step of supply chains. From a depot with identical vehicles of limited capacity, it consists in determining a set of vehicle trips of minimum total length, to satisfy the demands of a set of customers. In general, the number of vehicles used is a decision variable. The heterogeneous fleet VRP (HFVRP or HVRP) is a natural generalization with several vehicle types, each type being defined by a capacity, a fixed cost, a cost per distance unit and a number of vehicles available. The vehicle fleet mix problem (VFMP) is a variant with an unlimited number of vehicles per type. This paper presents two memetic algorithms (genetic algorithms hybridized with a local search) able to solve both the VFMP and the HVRP. They are based on chromosomes encoded as giant tours, without trip delimiters, and on an optimal evaluation procedure which splits these tours into feasible trips and assigns vehicles to them. The second algorithm uses a distance measure in solution space to diversify the search. Numerical tests on standard VFMP and HFVRP instances show that the two methods, especially the one with distance measure, compete with published metaheuristics and improve several best-known solutions.     

求解车辆路径问题的人工蜂群算法

采用人工蜂群算法对车辆路径问题进行求解,给出食物源的自然数编码方法,并采用邻域倒位方法生成候选食物源。应用算法求解了多个车辆路径问题的实例,并将结果与其它一些启发式算法进行了比较和分析。计算结果表明,人工蜂群算法可以有效求解车辆路径问题,同时也为算法求解其它一些组合优化问题提供了有益思路。     

A parallel evolutionary algorithm for the vehicle routing problem with heterogeneous fleet

Nowadays genetic algorithms stand as a trend to solve NP-complete and NP-hard problems. In this paper, we present a new hybrid metaheuristic which uses parallel genetic algorithms and scatter search coupled with a decomposition-into-petals procedure for solving a class of vehicle routing and scheduling problems. The parallel genetic algorithm presented is based on the island model and its performance is evaluated for a heterogeneous fleet problem, which is considered a problem much harder to solve than the homogeneous vehicle routing problem.     

蚁群算法研究与应用的新进展

蚁群算法是一种源于大自然生物界的仿生进化算法,具有自组织性、正反馈性、较强的鲁棒性和分布式计算等特性,且易于与其它算法相结合,在众多的复杂组合优化领域中有着广阔的应用前景。首先对蚁群算法的理论及其重要参数进行了阐述,继而分析了其在参数优化和智能融合方面的改进与应用;然后对其在车间作业调度问题、车辆路径问题、图像处理、电力系统优化等领域的应用进展进行了综述;最后对其理论研究和应用领域可能存在的问题及对策进行了探讨和展望。     

Active guided evolution strategies for large-scale vehicle routing problems with time windows

We present a new and effective metaheuristic algorithm, active guided evolution strategies, for the vehicle routing problem with time windows. The algorithm combines the strengths of the well-known guided local search and evolution strategies metaheuristics into an iterative two-stage procedure. More precisely, guided local search is used to regulate a composite local search in the first stage and the neighborhood of the evolution strategies algorithm in the second stage. The vehicle routing problem with time windows is a classical problem in operations research, where the objective is to design least cost routes for a fleet of identical capacitated vehicles to service geographically scattered customers within pre-specified time windows. The presented algorithm is specifically designed for large-scale problems. The computational experiments were carried out on an extended set of 302 benchmark problems. The results demonstrate that the suggested method is highly competitive, providing the best-known solutions to 86% of all test instances within reasonable computing times. The power of the algorithm is confirmed by the results obtained on 23 capacitated vehicle routing problems from the literature.