The effect of crowding on public transit user travel behavior in a large-scale public transportation system through modeling daily variations

In this paper, the crowding effect in a transit vehicle is modeled in a time-expanded network that considers the daily variation in passenger flows. The study models the daily variation of in-vehicle crowding in a real large-scale transit system. A transit assignment for this real network is modeled and implemented by constructing a crowding cost function that follows the valuation of crowding and by using the reliable shortest path finding method. The direct application of the crowding model to a real network for the Utah Transit Authority indicates that crowd modeling with multi-user classes could influence public transportation system planning and affect the revenues of transit agencies. Moreover, the addition of the disutility factor, crowding, does not always appear to cause an increase in disutility for transit users.     

道路运输行业安全监管现状分析及对策研究

结合道路运输行业安全监管现状,从道路运输行业安全监管职责和内容、监管方式、安全检查方面对道路运输行业安全监管存在的问题进行分析,并有针对性的提出了相应的建议和对策。     

基于价值函数的城市绿色交通规划评价

为了评价城市绿色交通,建立了城市绿色交通评价体系,包括环保性指标等3个评价项目和道路绿化率等8个评价指标,文章通过案例分析发现,价值函数法适用于城市绿色交通评价。采用专家打分法确定指标权重系数,并对指标进行无量纲化、同趋向化等处理,采用价值函数法计算评价体系得分。     

Estimation of origin-destination matrices from link counts and sporadic routing data

Estimation of origin-destination (OD) matrices from link count data is a challenging problem because of the highly indeterminate relationship between the observations and the latent route flows. Conversely, estimation is straightforward if we observe the path taken by each vehicle. We consider an intermediate problem of increasing practical importance, in which link count data is supplemented by routing information for a fraction of vehicles on the network. We develop a statistical model for these combined data sources and derive some tractable normal approximations thereof. We examine likelihood-based inference for these normal models under the assumption that the probability of vehicle tracking is known. We show that the likelihood theory can be non-standard because of boundary effects, and provide conditions under which such irregular behaviour will be observed in practice. For regular cases we outline connections with existing generalised least squares methods. We then consider estimation of OD matrices under estimated and/or misspecified models for the probability of vehicle tracking. Theoretical developments are complemented by simulation experiments and an illustrative example using a section of road network from the English city of Leicester.     

基于蚁群算法和群决策理论的动态路径优化研究

文章针对城市交通信号控制中的动态路径优化问题,综合考虑相邻交叉口间距和路段交通饱和度两个参数的影响,提出了一种基于蚁群算法和群决策理论的动态路径优化算法模型,并通过仿真实验,对比分析了该算法模型的有效性。     

我国海洋船舶污染防治法律制度的缺陷与对策

伴随我国经济和航运事业的快速发展,船舶营运造成了我国海洋环境的严重破坏,但我国防治船舶海洋污染法律制度的建设却严重滞后。在充分考量我国防治船舶海洋污染法律制度的现状的基础上,借鉴美国在相关法律制度建设上的立法经验,对我国防治船舶海洋污染法律制度的建设提出建议与对策。     

带超速保护功能的柴油机机旁气动操作系统设计

柴油机控制系统主要有气动控制系统、电-气混合控制系统、微机式控制系统、可编程控制器控制系统等,目前,我国大量船舶上使用的是气动控制系统或电-气混合控制系统,机旁气动操作系统是以上两种控制系统的重要组成部分。本文主要介绍了一种带超速保护功能的柴油机机旁气动操作系统,提高了柴油机旁气动操作系统的安全性。     

长江口深水航道南导堤上段整治建筑物损坏原因及对策

在长江口航道养护工作中,为查找南导堤上段局部整治建筑物损坏的原因,通过对现场的详细调查和对损坏区段的地形状况、水动力特征、水动力模型进行分析,得知损坏的主要原因,即在河势条件及水动力因素综合作用下,近堤边坡不断变陡,从而导致了损坏。据此编制修复设计方案,并完成修复,取得良好的效果。     

长江大保护战略下河口滩涂的保护对策研究

针对长江来沙持续减少引起河口滩涂侵蚀日益严峻的现象,提出长江口滩涂保护的重要性;并以九段沙、横沙东滩为研究典型,探讨分析不同定位滩涂宜采取的不同保护对策。结论如下:对于生态保护区滩涂,宜通过改变外围环境实施滩涂保护、促进滩面缓慢淤涨;对于非生态保护区滩涂,可采取积极主动的护滩措施,且可通过工程有目的地培育高-中-低滩有序分布的滩涂基底,在实现滩涂资源稳定的基础上提升滩涂生态品质,增强滩涂区域功能,积极响应长江大保护战略。     

京杭运河穿黄及黄河北航道走向探析

近年来,京杭运河黄河以北段复航呼声越来越高,京杭运河穿黄及黄河北山东段走向成为目前需要迫切解决的问题。本文通过对东平湖周边防洪工程现状分析,提出了穿黄位置、穿黄方案及穿黄线路走向;根据黄河北河系水网布置,提出了京杭运河黄河北山东段航道初步走向,为京杭运河黄河以北段复航工程提供技术参考。