货物多式运输服务网运能配置优化研究

运用离散优化方法,研究货物多式联运服务网运能配置问题,根据不同货物运输服务需求特性、各运输方式服务类型的频次以及各运输方式满足一定的运能配置和运能改造费用约束,构造了多式联运服务网络各运输方式间运能配置优化模型;利用多式联运的特点和区域组团网络结构进行算法设计,针对大规模节点采用分枝-切割进行求解可以提高求解效率;通过一个算例,对模型和算法的可行性和有效性进行了验证;最后通过敏感性分析说明了单位运能配置成本对运能配置的影响。     

基于改进遗传算法的多式联运路径优化研究

文中以荣森物流公司为研究背景,针对多运输方式多路径问题,提出一种改进的遗传算法,可同时解决运输方式的选择和路径的规划问题。通过建立多式联运路径优化模型,采用多参数编码方式,从而解决该类问题,同时为多式联运的相关决策和组织提供参考依据。     

Dynamic vehicle routing with anticipation in disaster relief

Pickup and delivery problems (PDP), where locations may both receive and send goods, are an extension of the classical vehicle routing problem. This paper considers the application of a routing and scheduling problem for forwarding agencies handling less-than-truckload freight in disasters. The approach evaluates the benefits of dynamic optimization anticipating varying travel times (i.e., the availability of connections in this case) as well as unknown orders (i.e., the integration of demand regions on short-notice) in the specific environment of emergencies. The objective is to avoid delays and increase equipment utilization. We model a multi-stage mixed integer problem which is able to operate under variable demand and transport conditions.     

一种车辆重载运输社会经济影响的评估方法

基于系统动力学(System Dynamics)理论建立公路货运系统的系统动力学模型,通过仿真分析车辆载重程度对货运需求、车辆使用决策、车型演化、车辆运输成本以及路面性能的长期动态作用,继而进行车辆重载运输的社会经济影响评估。最后形成一套完整的公路货运车辆重载运输对社会经济影响的系统化研究方法。基于实例的仿真结果表明,在货运车辆普遍重载的条件下,生产要素价格的变动、路面厚度的提高、路面维修间隔期的改变和公路税费标准的调整均不会对车流轴载水平乃至公路货运系统的运行产生根本性影响。在实施车辆载重限制后,系统行为又表现出以下重要特征:反直观性、远期与近期利益相矛盾、系统绩效受车辆载重标准与产业结构的影响较大。     

基于时间约束的物流运输路线优化

在分析车辆运输费用和运输时间的基础之上,建立一个以规定时间内最小费用为目标的物流调度路线优化数学模型。同时给出车辆路线问题的求解算法思路和计算流程,并结合实例,采用Dijkstra迭代方法,讨论该算法的应用。从而为在物流调度的车辆运输路线优化中实现在满足时间约束条件下达到运输费用最低提供依据和方法。     

Analysing the impact of restructuring transportation,production and distribution on costs and environment – a case from the Thai Rubber industry

Transportation and distribution are key elements to successful supply chains, however there is some disagreement regarding the impact of distribution and transportation restructuring on costs and the environment. This paper explores the use of an optimisation model of Thailand’s rubber industry supply chain, to assess the impact of distribution and transportation on costs and greenhouse gas emissions. It has previously been observed that there is a positive correlation between transportation cost reduction and environmental impact, nevertheless the correlation is not clearly established when the distribution system is restructured. This paper is divided into two parts: the first part examines the impact of transportation service capacity on distribution decisions; the second part of the paper aims to examine the impact of restructuring the distribution network considering multi-modal options on cost and greenhouse gas emissions. For both parts a scenario analysis is utilised in conjunction with an optimisation model to derive the best possible answer in terms of costs and GHG emissions. In this paper, the results obtained indicate that the impact on cost minimisation from the increase in rail freight service capacity is marginal, while the impact on GHG emission minimisation is more significant. In terms of short-sea shipping prices and service capacity, the scenario analysis shows a slight positive impact on cost minimisation but no positive or negative impact on GHG emission minimisation. Results also confirm that in terms of economic advantages, distribution network restructuring provides greater benefit to the industry than does capacity development for the transportation service.     

Vehicle flow formulation for two-echelon time-constrained vehicle routing problem

Two-echelon routing problems, including variants such as the two-echelon vehicle routing problem (2E-VRP) and the two-echelon location routing problem (2E-LRP), involve assignment and location decisions. However, the two-echelon time-constrained vehicle routing problem (2E-TVRP) that caters to from-linehaul-to-delivery practices does not involve assignment decisions. This routing problem variant for networks with two echelons has not yet attracted enough research interest. Localized or long-distance services suffer from the lack of the assignment decisions between satellites and customers. Therefore, the 2E-TVRP, rather than using assignment decisions, adopts time constraints to decide the routes on each of the two interacting echelons: large-capacity vehicles transport cargoes among satellites on the first echelon, and small-capacity vehicles deliver cargoes from satellites to customers on the second echelon. This study introduces a mixed integer linear programming model for the 2E-TVRP and proposes a heuristic algorithm that incorporates the savings algorithm followed by a variable neighborhood search phase. Illustrative examples are used to test the mathematical formulation and the heuristic and a case study is used to demonstrate that the heuristic can effectively solve realistic-size instances of the 2E-TVRP.     

生态旅游区废弃物回收的逆向物流选址-路径问题

研究了生态旅游区废弃物逆向物流网络设计问题,包括中转站选址和车辆路径问题,并建立了最小化选址费用和运输费用的模型。选址路径问题为NP困难问题,本文采用了四叉树原理划分满足车辆容量限制的收集区,将问题化为小型的TSP问题。     

A survey on pickup and delivery problems

This paper is the second part of a comprehensive survey on routing problems involving pickups and deliveries. Basically, two problem classes can be distinguished. The first part dealt with the transportation of goods from the depot to linehaul customers and from backhaul customers to the depot. The second part now considers all those problems where goods are transported between pickup and delivery locations, denoted as Vehicle Routing Problems with Pickups and Deliveries (VRPPD). These are the Pickup and Delivery Vehicle Routing Problem (PDVRP – unpaired pickup and delivery points), the classical Pickup and Delivery Problem (PDP – paired pickup and delivery points), and the Dial-A-Ride Problem (DARP – passenger transportation between paired pickup and delivery points and user inconvenience taken into consideration). Single as well as multi vehicle mathematical problem formulations for all three VRPPD types are given, and the respective exact, heuristic, and metaheuristic solution methods are discussed.      

Managing returnable transport items in a vendor managed inventory system

This paper addresses a closed-loop inventory routing problem with demand uncertainty, which manages the delivery operations to customers and pick-up operations of empty returnable transport items (RTIs) from customers. The problem involves decisions regarding forward and backward vehicle routes, the delivery and collection quantities, the amount of production in terms of the number of filled RTIs, and the number of RTIs produced/ bought by the vendor during the defined planning horizon. The problem considers the holding costs, fixed cost of operating vehicles, fuel consumption cost, producing/buying costs, cleaning costs of RTIs, and loading and unloading costs. We formulate the problem as a mixed integer linear programming model and propose a Relax and Fix based solution approach to solve large instances. We conduct extensive analyses on a case study derived from a fruit and vegetable distribution network and several hypothetical instances. Our analyses investigate the effects of several problem parameter changes (i.e., average collection rate, customer service level, cost of buying crate and handling cost) on the total logistics cost. Additional numerical analyses are performed to demonstrate the usage of the model for evaluating the cost of being more green and environmental-friendly. Moreover, experiments on relatively large-scaled problems allow us to demonstrate the potential benefits of the proposed heuristic     

Assessment of the internet impact on road transportation industry operational efficiency

The Internet of Things has been driving the development of China's transportation industry. This paper used a dynamic direct distance function Data Envelopment Analysis model with internet access as the input index to more comprehensively assess the efficiency and the improvements needed in the application of internet technology in the road transportation industries. It was found that (1) the average total efficiency was higher when the internet influences were considered than when they are not considered. (2) The commercial passenger vehicle, freight vehicle, passenger traffic, and freight volume efficiencies in most provinces were positively affected by the internet.     

面向多式联运的货运网络优化模型构建与应用

以多式联运货运网络为研究对象,综合考虑轴辐式网络中的规模效应、运输成本、时间及运输能力限制,构建多式联运货运网络模型。基于龙潭港货物运输实际,利用遗传算法对龙潭港多式联运枢纽网络优化模型进行求解,特别针对南京集疏运通道建设前后,分别运用模型求解,对南京联运方式变化进行对比分析,证明了在发展集疏运通道建设后,南京在运输网络中的地位进一步得到提高。     

公交实时信息化服务对乘客出行行为意向影响

为了解城市公交信息化服务对公交乘客出行方式转移的影响,以上海市杨浦区为例,进行关于公交信息化服务下乘客出行方式转移的调查,获取个人属性、公交出行经历、公交出行评价、出行方式转移意向以及公交信息服务需求等信息。从公交信息使用者角度,重点关注公交信息化服务对乘客出行方式转移的影响,分别构建信息化服务情境下(公交到站时间与计划出发时间相差过大和车辆未在提示的时间内到达)的公交出行方式转移二项logit模型。模型结果表明:乘客平均候车时间、是否经常使用公交到站服务、是否有道路拥挤车辆未按时进站等原因而产生出行延误的经历、公交信息准确性评价与是否有必要提示同公交线路连续班次的到站时间等因素对不同情景下的乘客出行方式转移具有显著影响。     

国内外农村客运研究综述

发展农村客运是解决我国交通运输领域的＂三农问题＂的重要研究方面。文中分别对国外发达国家和中国的农村客运研究情况进行了综述,理清了国内外对农村客运的研究热点,并找出了国内外农村客运研究的差异,指出进一步研究方向,为我国对农村客运研究的发展提供参考。     

铁路运输成本函数的实证应用

分析确定了在不同研究目的下铁路运输超对数成本函数的广泛适用性;研究了我国铁路客货运输成本函数的变量选择,进一步阐述了运输成本函数在铁路经济问题研究中的实证应用,通过分析规模经济和范围经济以确定垄断经营和客货运分离,通过分析引入竞争的福利影响来确定垄断经营与引入竞争决策选择的平衡点,通过分析要素价格弹性和替代弹性确定对铁路成本影响重大的要素及替代方案等。     

同城网络货运平台发展现状调查与分析

指出网络货运作为一种基于互联网技术的新型物流运作模式,对整合社会零散运力、实现信息高效共享、促进物流行业降本增效作用显著。基于对网络货运平台业务流程的深入分析,从平台、货主、司机三者之间的关系,对国内三家典型同城网络货运平台的运作流程进行调查分析。针对监管不到位、市场竞争激烈、服务功能单一等常见问题,提出整改意见和建议,以促进新业态下城市货运配送行业的健康发展。     

蚂蚁算法在复杂性运输路径问题中的应用——多车场多车型路径问题

车辆路径问题中,行驶路线往往取决于一系列约束条件,如配送中心个数,货物需求量,交发货时间,车辆容量限制等。要想达到一定的目标,如路程最短,费用最小,时间尽量少,车辆尽量少等,就得借劲于合适的算法去解决实际的问题。蚂蚁算法在解决著名的旅行商（TSP）问题上已取得了很好的成效,目前已陆续渗透到其他问题的求解上。文章主要针对多车场多车型车辆路径问题,用蚁群算法以及蚁群算法的优化算法去解决一些实际问题。     

基于SPFA的整车物流运输线路及运输方式的优化及求解

运输成本对物流企业的作用至关重要,而运用计算机辅助技术来解决整车运输线路优化的问题也一直是物流企业关注的重点。文中以安吉整车物流现有的运输网络为研究对象,以运输成本最低为目标,建立运输线路及运输方式的优化模型,并运用改进后的SPFA算法编程进行求解,从而解决运输线路及运输方式的选择问题。希望通过研究在降低物流运输成本方面做出一些有益的探索。     

基于人员和车辆可租赁条件下的车辆路径选配模型及优化

物流服务供应商面临的决策问题常常是复杂的规划问题。文中考虑短程的计划,物流服务供应商在需求点的时间窗、车辆的容积和人员的调度,包括租用的人员和车辆的条件下决定收发件路线,建立了路线和人员调度相结合的规划模型。采用节约启发式算法来求解车辆路径问题,得到路线安排的满意解。之后采用贪婪启发式算法对人员进行分配,通过实际案例得出:在租赁人员和车辆的情况下比不租赁人员和车辆总的费用更低。结果表明,启发式算法既能够满足时间限制,又能够节约运输里程和费用。     

基于Matlab物流配送路径优化问题遗传算法的实现

在物流管理学中。研究物流配送路径优化问题并选取恰当的配送路径。可以加快对客户需求的响应速度．提高服务质量，增强客户对物流环节的满意度。降低服务商运作成本。但由于物流配送路径优化问题是一个NP—hard问题，使用传统优化方法很难得到最优解或满意解。本文基于Matlab进行了物流配送路径优化问题遗传算法的编码．利用Matlab强大的数值计算能力较好地解决了这个难题并进行了实例验证．对物流企业实现科学快捷的配送调度和路径的优化有实际意义。