The relationship between land use and automobile travel utility: A Multiple Indicators Multiple Causes approach

The relationship between land use and the utility of automobile travel is examined by refining the utility concept, particularly by combining the microeconomic utility theory, which is concerned with the disutility of travel, and the perspective on the positive utility. A conceptual model is accordingly developed and then adjusted considering different purposes of travel. The purpose-specific models are tested through a Multiple Indicators Multiple Causes approach in Seoul, Korea, using datasets from a sample survey and geographic information systems. The major finding is that land use affects the utility mainly by changing synergy and affective utility rather than instrumental utility, which encompasses disutility variables. Among land use variables, the utility is found to be the most sensitive to the number of transit facilities for commuting and shopping travel and land use balance for leisure travel.     

Modelling users’ behaviour in inter-urban carsharing program: A stated preference approach

In this paper, the effects of a inter-urban carsharing program on users’ mode choice behaviour were investigated and modelled through specification, calibration and validation of different modelling approaches founded on the behavioural paradigm of the random utility theory. To this end, switching models conditional on the usually chosen transport mode, unconditional switching models and holding models were investigated and compared. The aim was threefold: (i) to analyse the feasibility of a inter-urban carsharing program; (ii) to investigate the main determinants of the choice behaviour; (iii) to compare different approaches (switching vs. holding; conditional vs. unconditional); (iv) to investigate different modelling solutions within the random utility framework (homoscedastic, heteroscedastic and cross-correlated closed-form solutions). The set of models was calibrated on a stated preferences survey carried out on users commuting within the metropolitan area of Salerno, in particular with regard to the home-to-work trips from/to Salerno (the capital city of the Salerno province) to/from the three main municipalities belonging to the metropolitan area of Salerno. All of the involved municipalities significantly interact each other, the average trip length is about 30 km a day and all are served by public transport. The proposed carsharing program was a one-way service, working alongside public transport, with the possibility of sharing the same car among different users, with free parking slots and free access to the existent restricted traffic areas. Results indicated that the inter-urban carsharing service may be a substitute of the car transport mode, but also it could be a complementary alternative to the transit system in those time periods in which the service is not guaranteed or efficient. Estimation results highlighted that the conditional switching approach is the most effective one, whereas travel monetary cost, access time to carsharing parking slots, gender, age, trip frequency, car availability and the type of trip (home-based) were the most significant attributes. Elasticity results showed that access time to the parking slots predominantly influences choice probability for bus and carpool users; change in carsharing travel costs mainly affects carpool users; change in travel costs of the usually chosen transport mode mainly affects car and carpool users.     

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提出了通过具体的效用度量对出行者路径选择行为进行分析的方法。从传统的期望效用理论和前景理论两个方面，对一份关于出行者路径选择的调查数据进行了分析；验证了出行者群体在不确定环境下进行路径选择时，效用度量是基本决策规则，并且其效用度量体系与前景理论针对一般经济主体的效用度量体系接近。最后借助图形说明了合理设定出行者风险态度水平的重要性。     

一种基于效用函数优化的计算网格资源分配策略

提出了一种基于效用函数优化的网格资源分配策略．试图利用效用函数和竞标函数对网格资源进行合理分配，采用拉格朗日方法对网格任务Agent效用函数进行优化，从而可使网格任务Agent在能估计资源节点拥塞度，并能完成其所有任务的情况下，产生一个合理的费用预算．对网格任务Agent的竞标函数的特征进行了研究分析，研究结果表明如果网络状态不变，网格任务Agent不能通过改变投标来获取效益．这种恒定性在任务Agent不知晓竞标结果的情况下，可使它无需做徒劳的重投标．     

不同交通方式服务可靠度与客流量间的灵敏度分析

分析了交通方式服务可靠性的特点和计算方法，并将其引入到效用函数中，提出了考虑方式服务可靠性的效用函数模型，给出了不同交通方式问的均衡配流模型．利用灵敏度法分析了不同方式出行时间可靠度改善对客流的影响关系，给出了具体的关系模型．通过一实例表明该模型与算法是有效的。     

成品湿法橡胶沥青AR-SMA13的应用研究

结合成品湿法橡胶沥青AR-SMA13的应用研究情况,从配合比设计、施工工艺、经济性等方面进行了全面介绍,实践表明,其性能优异,综合成本相比同类沥青产品低,性价比高,具有良好的推广应用价值.     

一类有竞争的物流配送中心选址模型

对已有多个配送中心存在的前提出，新增配送中心为获取最大市场占有量如何进行有效的选址决策问题进行了研究，建立了一个选址决策模型，把求解的问题归结为无约束的非线性规划问题，并给出了迭代算法，最后对如何解决考虑多种选址影响因素及多个新增配送中心的复杂情况进行了讨论。     

二甲醚—柴油混合燃料应用研究

分析了二甲醚物理化学特性,并在增压中冷多缸柴油机上进行了低比例二甲醚与高比例柴油混合燃烧试验研究。结果表明,通过优化供油系统参数,在柴油机上掺烧D30(二甲醚柴油质量分数比3∶7),动力性与原柴油机相当,燃油经济性有所改善,PM排放大幅度下降,NOx在整个负荷范围内得到控制。     

基于Nested Logit 模型的铁路旅客客运产品选择研究

通过成都-武汉既有线出行旅客的问卷调查,以及样本数据的归纳分析,对旅客客运产品选择行为特征进行描述.基于随机效用最大化理论,以乘车方式与客运产品作为选择肢,旅客主体、出行特性及列车服务特性的各项指标作为效用变量,构建了乘车方式位于上层、客运产品位于下层的Nested Logit 模型.模型的上下层参数标定结果表明,旅客的收入状况、出行目的、出行距离、列车票价及运行时间对其乘车方案选择具有显著影响,旅客的年龄、出行费用来源、收入状况、出行距离,以及列车票价、运行时间对其客运产品选择具有显著影响.模型能较为准确地反映铁路客运产品的实际需求,从而为其合理设计与调整提供理论依据.     

城市轨道交通车辆基地室外综合管沟的应用研究

室外管线综合设计是城市轨道交通车辆基地设计的重点和难点,通常室外管线多以直埋的方式敷设于地下,但这种方式在设计、施工、运营维护阶段均存在着一些问题,因此提出了在室外设置综合管沟的方式,尽可能解决目前出现的问题.针对相关问题,提出了设置室外综合管沟的必要性和意义,从入沟管线种类分析、综合管沟管线布置原则、断面设计、特殊节点设计以及管沟附属工程等方面介绍室外综合管沟在车辆基地的具体应用情况.