Pick‐up locations and bus allocation for transit‐based evacuation planning with demand uncertainty

This paper develops a decision‐support model for transit‐based evacuation planning under demand uncertainty. Demand uncertainty refers to the uncertainty associated with the number of transit‐dependent evacuees. A robust optimization model is proposed to determine the optimal pick‐up points for evacuees to assemble, and allocate available buses to transport the assembled evacuees between the pick‐up locations and different public shelters. The model is formulated as a mixed‐integer linear program and is solved via a cutting plane scheme. The numerical example based on the Sioux Falls network demonstrates that the robust plan yields lower total evacuation time and is reliable in serving the realized evacuee demand. Copyright © 2012 John Wiley & Sons, Ltd.     

The Share-a-Ride problem with stochastic travel times and stochastic delivery locations

We consider two stochastic variants of the Share-a-Ride problem: one with stochastic travel times and one with stochastic delivery locations. Both variants are formulated as a two-stage stochastic programming model with recourse. The objective is to maximize the expected profit of serving a set of passengers and parcels using a set of homogeneous vehicles. Our solution methodology integrates an adaptive large neighborhood search heuristic and three sampling strategies for the scenario generation (fixed sample size sampling, sample average approximation, and sequential sampling procedure). A computational study is carried out to compare the proposed approaches. The results show that the convergence rate depends on the source of stochasticity in the problem: stochastic delivery locations converge faster than stochastic travel times according to the numerical test. The sample average approximation and the sequential sampling procedure show a similar performance. The performance of the fixed sample size sampling is better compared to the other two approaches. The results suggest that the stochastic information is valuable in real-life and can dramatically improve the performance of a taxi sharing system, compared to deterministic solutions.     

Plastic deformation of ship plate subjected to repeated patch loads at different locations - Elastoplastic numerical analysis and design equation

Ship structures may be subjected to repeated random patch loads at different locations. Under these circumstances, ship plates will have large accumulated permanent deformations, which will result in some serious negative effects on their work and safety performance. Therefore, the elasto-plastic response of ship structure under repeated patch loads at different locations are studied by using finite element method. The permanent deformations of plate in the whole loading and unloading process are investigated. In addition, the residual stress and plastic strain states of the panel and stiffeners are studied based on a typical wheel-on-deck interaction scenario. Moreover, according to Hughes's hypothesis, the equivalent method between repeated patch loads at different locations and full uniform pressure load is studied. Considered the influence of plate slenderness, the improved formula for equivalent load coefficient is proposed, showing a good correlation with experimental data and numerical results. The proposed equivalent method can be used for estimating the permanent deformations of ship structures under repeated patch loads at different locations in ship life.     

基于DENCLUE聚类算法的交通事故多发点鉴别方法

针对目前交通事故多发点鉴别常用方法存在的问题,引入了DENCLUE聚类算法用于事故多发点鉴别。对DENCLUE聚类算法的基本原理,基本定义及计算步骤进行了阐述,重点分析了该算法用于事故多发点鉴别的可行性。实例计算结果表明：与传统事故多发点鉴别法方法相比,该算法能有效的避免对排查位置进行事先划分,实现任意长度聚类;同时,在事故数据小样本的情况下,能充分凸显道路沿线的危险性,可以有效地应用于事故多发点鉴别的研究。     

基于模糊品质机能法的第三方物流配送中心选址方法研究

配送中心选址对第三方物流企业（3PLS）来说至关重要，而当前提出的许多选址模型，主要以成本或利润为目标函数。进行配送中心选址决策时常忽略客户因素．品质机能展开法（QFD）是一种能将客户心声导入决策过程的系统化和结构化方法。文中提出了一个基于品质机能法，并综合应用模糊集理论、群体决策理论的3PLS的配送中心选址模型．模型能从3PLS和客户多角度考虑配送中心选址需求，可反映决策过程中的模糊性和群体性决策的特点。最后，应用案例说明了该方法的有效性。     

城市公共交通常乘客通勤出行提取方法

为挖掘公共交通通勤出行精准化特征，从追踪出行链的角度出发，利用公交与轨道多源数据研究常乘客通勤出行提取方法。通过选取潜在职住地设置高频职住地集合，提出公共交通常乘客职住地识别算法，结合出行链起讫站点与职住地空间信息匹配提取通勤出行链，并将常乘客出行分为home-work通勤、work-home通勤和非通勤出行。以北京市“回天地区”公交与轨道出行链数据为例，提取常乘客通勤出行。结果表明：常乘客职住地识别率达到85.9%，常乘客通勤出行和非通勤出行在出行时空分布和出行方式上存在明显差异，通勤出行提取可为北京市面向常乘客开展“预约出行”并分析其出行需求动态特征变化提供依据。     

Routing and charging locations for electric vehicles for intercity trips

This study addresses two problems in the context of battery electric vehicles (EVs) for intercity trips: the EV routing problem and the EV optimal charging station location problem (CSLP). The paper shows that EV routing on the shortest path subject to range feasibility for one origin–destination (O–D) pair, called the shortest walk problem (SWP), as well as a stronger version of the problem – the p-stop limited SWP – can be reduced to solving the shortest path problem on an auxiliary network. The paper then addresses optimal CSLPs in which EVs are range feasible with and without p-stops. We formulate the models as mixed-integer multi-commodity flow problems on the same auxiliary network without path and relay pattern enumeration. Benders decomposition is used to propose an exact solution approach. Numerical experiments are conducted using the Indiana state network.     

Review of optimal sensor location models for travel time estimation

The problem of optimally locating fixed sensors on a traffic network infrastructure has been object of growing interest in the past few years. Sensor location decisions models differ from each other according to the type of sensors that are to be located and the objective that one would like to optimize. This paper surveys the existing contributions in the literature related to the problem of locating fixed sensors on the network to estimate travel times. The review consists of two parts: the first part reviews the methodological approaches for the optimal location of counting sensors on a freeway for travel time estimation; the second part focuses on the results related to the optimal location of Automatic Vehicle Identification (AVI) readers on the links of a network to get travel time information.     

The impact of transit station areas on the travel behaviors of workers in Denver,Colorado

Transit development is one planning strategy that seeks to partially overcome limitations of low-density single use car oriented development styles. While many studies focus on how residential proximity to transit influences the travel behaviors of individuals, the effect of workplace proximity to transit is less understood. This paper asks, does working near a light rail transit station influence the travel behaviors of workers differently than workers living near a station? We begin by examining workers’ commute mode based on their residential and workplace proximity to transit station areas. Next, we analyze the ways in which personal travel behaviors differ between those who drive to work and those who do not. The data came from a 2009 travel behavior survey in the Denver, Colorado metropolitan area, which contains 8000 households, 16,000 individuals, and nearly 80,000 trips. We measure sustainable travel behaviors as reduced mileage, reduced number of trips, and increased use of non-car transportation. The results of this study indicate that living near a transit station area by itself does not increase the likelihood of using non-car modes for work commutes. But if the destination (work) is near a transit station area, persons are less likely to drive a car to work. People who both live and work in a transit station area are less likely to use a car and more likely to take non-car modes for both work and non-work (personal) trips. Especially for persons who work near a transit station area, the measures of personal trips and distances show a higher level of mobility for non-car commuters than car commuters – that is, more trips and more distant trips. The use of non-car modes for personal trips is most likely to occur by non-car commuters, regardless of their transit station area relationship.