灾难救援应急物资配送问题的研究现状及发展方向

应急物资分配和车辆路径选择是灾难救援研究的2个核心问题。通过分类综述国内外学者关于应急物资分配和应急车辆路径研究的模型及结论,重点分析了模型的目标函数、约束条件、算法及优缺点。在灾难救援应急物资配送问题的研究分析中,提出考虑需求不确定性、建立更符合实际的模型、探索启发式算法、结合其他理论研究等研究方向。     

基于应急物资优先权的铁路空车调配研究

近年来突发性的自然灾害发生频繁,应急物资调运优化问题成为研究热点.基于模糊综合评判方法对应急物资优先权进行了分析,并结合车种代用,构建了考虑应急物资优先权的车种代用空车调配模型.分析表明,若适当选取多目标的权重系数,则该多目标模型既适用于应急救援过程中的物资调运,又适用于日常的物资调运.     

多出救点应急调度研究

针对多出救点、多受灾点应急物资调度问题,在满足时间约束条件下,建立以应急出救总行程最短和应急车辆数最少的双目标模型。在判断各受灾点配送方式基础上,考虑物流应急中心供给量、车辆载重、时间限制,先用启发式算法分派直送车辆的调度任务,再对剩余受灾点设计遗传算法调整各物流中心的配送任务和各车辆的配送顺序,得到车辆的行车路线。通过实例分析说明模型的合理性与算法的有效性。     

疫情下考虑均衡松弛库存的双目标应急物流网络优化研究

新冠疫情爆发后，对应急物资库存与应急物流的选址路径问题协同优化，可有效保障应急救援工作的开展。文章提出了在避免应急物资库存耗尽的情况下如何增大松弛库存问题，采用转运结合的公铁联运协同配送模式，构建了应急物流网络的双目标优化数学模型，以提高均衡松弛库存，降低总时间成本。采用遗传算法求解双目标优化问题，解决了应急物流中心的选址、公铁联运路径以及应急物资的配送量等问题。通过湖北省应急物流的算例验证方法的可行性，研究结果表明，在应急物资有限的情况下，不同选址路径优化方案的均衡松弛库存目标和时效性目标满足Pareto最优。应急部门可以结合疫情选择合适的应急物流网络优化方案，以实现在避免物资耗尽的情况下最大限度的均衡松弛库存。     

铁路应急物资运输网络中RAP问题的集成优化模型

通过概述国内外对铁路网络失效线路修复和应急物资配送问题的研究成果,针对RAP问题,将铁路运输网络中的修复失效线路与应急物资配送问题进行集成优化,以提高铁路应急物资的配送效率。首先对铁路应急物资运输网络进行脆弱性评估,其次以物资配送总效率最大和修复路径总延时最小为目标建立RAP的集成优化模型,然后利用0-1变量将模型转化为计算软件易于操作的规划模型,最后通过算例分析验证该模型的可行性和实用性。     

基于双层规划的应急医疗物资物流网络优化及其算法研究

在突发事件发生前预先安排应急医疗物资配送,将大大提高救援效率。本文对基于双层规划的应急医疗物资物流网络优化问题进行分析,并通过对相关文献研究,归纳总结出双层规划模型以及应急医疗物资物流网络优化问题的研究现状,并将用于求解NP-Hard问题的启发式算法进行概括总结,最后总结研究现状,指出不足和下一步研究方向。     

基于Vague集的铁路车流径路优化

为实现车流径路时间消耗与距离消耗的双重优化,求得更合理径路,针对以往径路优化模型没有考虑径路走行时间的问题,将车辆在车流径路上的运行时间分为在途时间与在站时间,并结合信息化手段对在站时间的历史数据进行统计分析来确定在站时间参数,建立以车辆在路网上运行的路径最短和时间最短为目标的多目标优化模型,采用?K?短路算法求出满足约束的合理径路集,并引入Vague?集来对合理径路集进行评价,从而得到满意解,最后通过算例验证了模型的有效性与算法的可行性。     

铁路应急物资储备点选址研究

通过概述国内外对于应急管理和应急系统选址问题的研究成果,根据铁路应急物资储备点选址问题的特点,以总货物周转量最小为目标,考虑以最少的储备点数量覆盖全部应急物资需求点,在铁路应急物资储备点的运输能力约束和应急物资需求点的需求约束条件下,建立铁路应急物资储备点选址模型,并采用LINGO软件对模型进行求解。算例分析表明,该模型适用于铁路应急物资储备点选址问题。     

基于Dijkstra算法的突发事件下列车最短径路的设计与实现

<正>1.引言突发事件（比如：(1)自然灾害：暴风雨、洪涝、地震、暴雪、台风等导致的线路故障或车站能力不足(2)事故灾难导致的线路故障或车站能力不足(3)其他因素）的影响，对铁路运输造成了巨大的经济损失。研究突发事件下列车运行径路选择问题，有助于在突发事件下快速找出最短路径，及时完成铁路客货运输任务，减少突发事件给铁路运输带来的一系列损失。2.Dijks tra算法求最短径路2.1Dijks tra算法基本思想Dijks tra算法是典型的单源最短路径算法，用于计算一个节点到其他所有节点的最短路径。     

我国应急物流平台构建研究

近几年来,我国先后爆发的地震、水灾、雪灾等造成了巨大的人员伤亡和财产损失。为抗灾救灾,减少损失,在尽量短的时间内以最简洁的流程、最快捷的方式供应各种应急物资势在必行。为此,笔者从应急物流信息平台、指挥平台和物理实现平台的3个方面对应急物流平台的构建进行探讨。     

中泰铁路通道物流枢纽遴选与布局研究

中泰铁路的修建将极大促进沿线成员国之间的贸易合作与交流,遴选与布局中泰铁路通道物流枢纽对物流的高效运输起着重要作用。阐述物流枢纽遴选与布局研究现状,提出构建中泰铁路通道物流枢纽遴选及布局模型,选取云南、泰国铁路沿线13个城市为研究对象,对中泰铁路通道物流枢纽的遴选和布局进行实证分析。研究结果表明:可以通过遴选模型确定中泰铁路经济带的物流枢纽节点,通过布局模型进一步确定中泰铁路国际物流通道的一级物流枢纽及二级物流枢纽,为中泰铁路通道物流枢纽规划布局提供研究依据。     

Shortest path or anchor-based route choice: a large-scale empirical analysis of minicab routing in London

Understanding and modelling route choice behaviour is central to predicting the formation and propagation of urban road congestion. Yet within conventional literature disagreements persist around the nature of route choice behaviour, and how it should be modelled. In this paper, both the shortest path and anchor-based perspectives on route choice behaviour are explored through an empirical analysis of nearly 700,000 minicab routes across London, United Kingdom. In the first set of analyses, the degree of similarity between observed routes and possible shortest paths is established. Shortest paths demonstrate poor performance in predicting both observed route choice and characteristics. The second stage of analysis explores the influence of specific urban features, named anchors, in route choice. These analyses show that certain features attract more route choices than would be expected were individuals choosing route based on cost minimisation alone. Instead, the results indicate that major urban features form the basis of route choice planning – being selected disproportionately more often, and causing asymmetry in route choice volumes by direction of travel. At a finer scale, decisions made at minor road features are furthermore demonstrated to influence routing patterns. The results indicate a need to revisit the basis of how routes are modelled, shifting from the shortest path perspective to a mechanism structured around urban features. In concluding, the main trends are synthesised within an initial framework for route choice modelling, and presents potential extensions of this research.     

Route choice behavior in a radial structured urban network: Do people choose the orbital or the route through the city center?

We use a license plate survey to study route choice through the city center of a medium-sized Dutch city, in which car drivers can basically choose between the orbital and center ring. For a sample of 1397 trips, we fitted a multinomial logit regression model. According to this model, route choice is relatively little influenced by actual travel time. This corresponds with the fact that many drivers did not choose the shortest time route. Travel distance in combination with one “route type velocity” for all orbital routes, and one route type velocity for all center routes is the most decisive factor. The route type velocity indicates how fast and attractive routes of that type are (being perceived). The results support the hypothesis that orbital routes are more attractive as these routes avoid the busy city center. This effect is however partly offset by the fact that drivers also prefer routes in the direction of their destination. These direct routes are mainly center routes. The results show the importance of considering complete routes in relation to their location and not only as a set of links and nodes when modeling route choice.     

基于多重图的物流链选择决策模型及算法研究

为了解决由物流链结构特性确定的最优物流链的选择问题,提出了基于多重图的物流链选择决策模型。通过讨论物流链的结构特性,在物流节点和物流路径均有费用出现的情况下,建立了同一位置有多个物流节点和物流路径可供选择的,以多重图作为拓扑形式的物流链选择决策模型。针对Dijkstra算法不能解决多重图中节点具有权值的问题,对算法进行改进,通过虚拟的方式将多重图转化为简单图,并将原节点的权值分解到简单图中相应的边上,使原问题转换为简单图的最短路径问题进行求解。最后,用一个算例进行了分析,算例表明,该算法对规模不大的物流链网络选择决策问题求解是可行的。     

A GIS-based toolkit for route choice analysis

This paper develops and applies the route choice analysis (RCA) toolkit. This GIS-based toolkit generates a suite of over 40 variables describing route characteristics such as distance, travel time, speed statistics, number of intersections, number of turns, number of stop signs/stop lights, and a measure of route circuity, to name a few. The input to the toolkit is one or more routes, which can be obtained from global positioning system (GPS) data or some other means (e.g., shortest path). While the toolkit is designed to support route choice modeling by generating variables that have been tested in previous modeling efforts, we demonstrate its utility by testing the hypothesis that workers choose routes to minimize either travel time or distance between home and work. A GPS-enhanced data set of 237 observed routes for home-to-work trips collected for auto drivers in Halifax, Nova Scotia, Canada is used in our analysis. We find that the null hypothesis is refuted - that is, a comparison of observed routes to their shortest-path alternatives based on time and distance via inferential statistics indicates that observed routes are significantly longer compared to their alternatives. This finding suggests that workers may choose routes based on other route attributes. The attributes generated by the RCA toolkit for observed, shortest time, and shortest distance routes are compared and significant differences are noted.     

Intermodal routing of Canada–Mexico shipments under NAFTA

This paper obtains the optimal routings for intermodal containerized transport from Canada to Mexico. Such traffic is being stimulated by the North American Free Trade Agreement (NAFTA), but the cost and lead times of feasible routes are not well known. We summarize the links and routes to Mexico on which one or more carriers now operate, and then determine non-dominated tradeoffs between cost and service. Every southbound route from Canada requires a transshipment point in the southern or southwestern U. S. Feasible transshipment points are also candidate locations for a manufacturing ‘twin plant’, a distribution centre, or a transportation hub. Here, as a first step in this bigger problem, a network is constructed between five Canadian origins and three important Mexican destinations. Each link employs available intermodal services whose transit time and transportation cost are obtained through industry sources. A shortest-path algorithm enables calculation of the route requiring least time and the route of minimum cost. Non-dominated time/cost tradeoffs are identified for each origin–destination pair. After including inventory expenses (by parametrizing the unit value of lead time), total-cost curves then eliminate some routing alternatives. Guidelines are provided on the effects of mode, carrier, and O–D locations on selection of intermodal routes to Mexico. Finally, two new intermodal services are proposed and their benefits discussed.     

The desired quality of integrated multimodal travel information in public transport: Customer needs for time and effort savings

Travel information is one of the factors that contribute to the quality of public transport. In particular, integrated multimodal travel information (IMTI) is expected to affect customers’ modal choice. The objective of this research is to identify customers’ desired quality of IMTI provision in public transport. Customers’ desired IMTI quality can vary throughout the pre-trip, wayside and on-board stages of a journey. The main determinants are time savings (travel and search time) and effort savings (physical, cognitive, and affective effort). In a sample of Dutch travellers with a substantial share of young persons, the pre-trip stage turns out to be the favourite stage to collect IMTI when planning multimodal travel; desired IMTI types in this stage are used to plan the part of the journey that is made by public transport. Wayside IMTI is most desired when it helps the traveller to catch the right vehicle en route. On-board travellers are most concerned about timely arrival at interchanges in order to catch connecting modes. In the whole travel process, travel time is the most important saving. Apart from that, pre-trip search time savings are also desired, while en route affective effort is more important than cognitive effort.     

Comparing distance,time, and metabolic energy cost functions for walking accessibility in infrastructure-poor regions

Accessibility is a widely used concept in transportation planning and research. However a majority of the literature is concerned with accessibility in infrastructure-rich regions where it is used to assess the output of infrastructure. Relatively scant attention in contrast has been paid to the topic of accessibility in infrastructure-poor regions. These are regions characterized by non-homogeneous landscapes with limited or no transportation infrastructure. Even studies that deal with infrastructure-poor regions tend to transpose the methods used elsewhere. This practice seems inappropriate when mobility happens by active rather than motorized modes since the effort required for movement is likely different. The objective of this paper is to compare distance, time, and metabolic energy cost functions in walking accessibility. To this end, we present a case study of accessibility to water in central Kenya. The results indicate that Euclidean distance, surface distance, and travel time correlate better between them than any of them does with metabolic energy. Furthermore, while shortest paths tend to be symmetric for distance and time criteria, under consideration of metabolic energy expenditure pathways change significantly depending on the direction of movement. This has implications for measuring accessibility and equity. By providing alternate mechanisms for valuing the cost of movement, this research suggests avenues to consider vulnerable populations, such as pregnant women who require greater nutritional intake and expend more energy per unit activity. Directions for further research include certain trade-offs between route choice variables across various applications, for example, walking and cycling route choice algorithms.     

基于混合禁忌搜索算法的物流配送路径优化问题研究

在对配送路径优化问题进行描述的基础上,建立物流配送路径优化问题的数学模型,提出了一种求解车辆路径问题的混合禁忌搜索算法。在该混合算法中,通过车辆—任务分配结构的划分,将大规模问题拆分成可并行计算的若干小规模问题,减少了算法的计算时间。并通过理论分析和仿真算例,证明了该混合禁忌搜索算法的有效性。     

铁路客运中转径路计算模型研究

针对目前径路计算中缺乏实时性、径路维护工作量大、径路选择缺乏灵活性等问题,从分析径路计算方式人手,结合车站发售通票业务特点,提出一种改进的统一径路计算模型。该模型充分平衡预先计算与实时计算的优点,在保证径路有效性和合理性的前提下,对径路计算中的车站个性径路信息和全路共性信息进行有效剥离,从根本上解决了径路计算存在的问题。