旅客列车到发时间域的优化模型与算法

旅客列车的开行方案必须体现以旅客为本,服务旅客、方便旅客的原则,而旅客出行的方便与否,主要体现在旅客列车出发与到达时刻是否合理.因此,本文首先定义了旅客列车合理始发、合理到达时间范围的概念,并研究该范围内不同时段旅客出行的方便度,绘制方便度曲线.然后建立了以最大程度方便旅客出行为目标的指派模型,实现了求解该模型的蚁群算法.最后以成都站为实例,对各始发列车的发车时间域进行优化.通过验证,本文模型和算法具有可行性.     

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出行信息的搜寻与获取是驾驶员出行决策的重要依据.为获取驾驶员的出行信息搜寻行为特征,以昆明市412个样本数据库为基础,建立驾驶员出行信息搜寻行为的因果和过程结构方程模型(SEM),并拟合各变量之间的路径关系.其中,驾驶员出行信息搜寻的因果结构方程模型重点分析个体属性、信息源因素及环境因素与搜寻行为之间的关系;驾驶员出行信息搜寻的过程结构方程模型则模拟驾驶员的出行信息搜寻过程.结果表明：驾驶员由于自身属性的不同在信息源与搜寻行为上存在显著差异,搜寻行为中驾驶员对出行信息的认知及信息源的选择是重要的影响因素.此外,驾驶员出行信息搜寻过程模型主要受到个体属性与信息需求的影响.     

基于异构模型的铁路出发旅客衔接时间价值

旅客时间价值是开展区域综合交通一体化研究的重要参数.本文针对现有文献中铁路旅客衔接时间价值研究较少、异构模型计算结果的比较不够充分等问题,以成都铁路东客站出发旅客衔接方式选择SP数据为依托,建立了MNL、ML、LCL、Hybrid等异构模型,对异构模型所得旅客个体和样本总体的等候时间价值、车内时间价值进行了比较.结果表明：模型结构对时间价值求解有较大影响,ML中单侧三角分布模型求解结果较为合理;Hybrid模型在拟合效果上表现优良,但在个体等候时间价值求解结果中呈现出较为明显的偏态性,给总体统计描述带来一定的困难.由于目前尚无关于时间价值的明确比选方法,应用中可考虑取异构模型计算结果的均值.     

地铁联络通道人工冻结粉质粘土变形与温度特性试验研究

为研究温度对粉质粘土变形特性的影响,以冻结粉质粘土为研究对象,通过三轴剪切试验,研究了不同温度条件下粉质粘土变形特性.试验结果表明:温度对土体的变形和强度存在显著影响.同一偏应力作用下,温度越低,变形越小.温度与冻结粉质粘土强度大致呈反余切函数关系.冻结粉质粘土应力-应变关系呈硬化型,无峰值强度.未冻粉质粘土应力-应变关系呈软化型,有峰值强度.依据Duncan-Chang模型建模思路建立了以温度为影响因子的冻结粉质粘土本构模型.偏应力和应变呈幂次函数关系.温度则主要通过幂次函数的系数A和B影响冻结粉质粘土的应变.最后,将建立的本构模型导入有限元分析软件MIDAS中,并以沈阳地铁DK11+ 395联络通道处工程为例,对冻结法施工过程中的土体变形进行了数值模拟.数值计算结果与现场监测结果吻合程度较好,验证了所建立本构关系模型的有效性.     

翻译伦理视阙下归化和异化的对立统一

归化与异化两种翻译策略长期以来一直存在于一种二元对立状态.翻译作为一种涉及原文作者、译者以及译文读者三方的交际行为,在某种程度上受到道德和一定社会规范的制约,因此需要从伦理学的角度审视翻译活动.切斯特曼的四大翻译伦理模式认为翻译体现了不同的伦理价值,在不同的伦理价值关照下的翻译策略也不是固定和唯一的,只有将归化和异化两种策略有机结合起来才能有效处理翻译中的各种矛盾.     

Synergies between Adjacent Beach-Nourishing Communities in a Morpho-Economic Coupled Coastline Model

Beach “nourishment” consists of placing sand on an eroding beach. The widened beach provides increased storm protection to adjacent structures and improved recreational benefits, but is most often transient, requiring on-going, repeated nourishment episodes. Numerical models of beach nourishment typically address such questions as how long a widened beach will last; economic models compare the benefits and costs of preserving a stretch of beach without regard to its geomorphic evolution. Neither have addressed the physical nor economic interactions between adjacent nourishing communities. Here, we couple a numerical model of coastline evolution and a cost-benefit model of beach nourishment, allowing adjacent communities to make dynamic nourishment decisions. Beach nourishment benefits adjacent communities both “updrift” and “downdrift.” The total amount of money spent on nourishment activities can decrease by as much as 25% when adjacent communities both conduct on-going nourishment projects, as opposed to the case where each community nourishes in isolation.     

Part 2. Beyond single-outcome models: Decompositions of aggregate and disaggregate road safety risk

The second part of the state-of-the-art focuses on the development of the founders' double streams explaining single-outcome indicators (probability of accidents and fatalities, respectively) by fixed form regression, as outlined in the Part 1. Following Page (1997, pp. 67–122, 2001) and others, we use as turning point of the evolution of both aggregate and discrete approaches the DRAG-1 model of 1984, itself based on aggregate data, which introduced four key innovations in principle applicable to both streams.     

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为识别区域综合交通系统能耗驱动因子,测算其对系统能耗的贡献度,将驱动因素分为规模效应、结构效应和技术效应,采用ASIF数据构造原理和时序列回归法识别各因子的相关性,运用迪氏分解方法建立扩展LMDI分解模型,计算各因子能耗贡献度.计算表明,规模效应和技术效应的影响程度在逐渐减弱,结构效应的影响程度在逐渐增加;运输结构还需要进一步优化,对系统能耗的影响还有很大下降空间;近年来能耗效率已经得到很大提高,但能耗效率对能耗的贡献正在逐渐减弱,未来提高运输强度对降低能耗有明显效果.经实证检验,计算模型可靠、结论可信,能为区域综合低碳交通政策制定提供更科学的依据.     

A Modeling Framework for Bus Rapid Transit Operations Evaluation and Service Planning

Abstract

In this paper, we present a dynamic traffic assignment-simulation modeling framework (DYNASMART-P) to support the evaluation and planning of Bus Rapid Transit (BRT) services in urban transportation networks. The model represents the different characteristics associated with BRT operations such as: exclusive right-of-way lanes, limited-stop service, signal prioritization at congested intersections, and enhanced bus stops to reduce passenger boarding times. A set of simulation experiments is conducted using the model to study the impact of introducing a hypothetical BRT service in the Knoxville area in the State of Tennessee. In these experiments, the different operational characteristics of BRT are evaluated in terms of potential impact on transit ridership and on the interacting auto traffic. The results illustrate the advantages of BRT for increasing transit ridership and improving overall system performance.     

The treatment of traffic in the Dutch environmental outlooks: the role of science in policy making and policy evaluation

The Dutch National Institute of Public Health and Environmental Protection publishes Environmental Outlooks in which 25‐year projections are made. These Outlooks quantifying the environmental problems, form the scientific basis for Dutch environmental policy. Traffic and transport is one of the main sectors causing environmental problems. The emissions and energy use of all relevant categories (road traffic, non‐road traffic) are based on model simulations with models. This paper describes the main models used.

If present policy is implemented only a minority of the environmental targets will be met.

If a sustainable transport system for the Netherlands means a large reducton in CO₂ emissions and energy use after 2010 a stronger emphasis on both technical and non‐technical measures (such as land‐use planning combined with public transport improvements) for the period until 2010 is needed than proposed in the Second Transport Structure Plan, unless a sustainable energy source becomes available.