A nested recursive logit model for route choice analysis

We propose a route choice model that relaxes the independence from irrelevant alternatives property of the logit model by allowing scale parameters to be link specific. Similar to the recursive logit (RL) model proposed by Fosgerau et al. (2013), the choice of path is modeled as a sequence of link choices and the model does not require any sampling of choice sets. Furthermore, the model can be consistently estimated and efficiently used for prediction.A key challenge lies in the computation of the value functions, i.e. the expected maximum utility from any position in the network to a destination. The value functions are the solution to a system of non-linear equations. We propose an iterative method with dynamic accuracy that allows to efficiently solve these systems.We report estimation results and a cross-validation study for a real network. The results show that the NRL model yields sensible parameter estimates and the fit is significantly better than the RL model. Moreover, the NRL model outperforms the RL model in terms of prediction.     

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.     

基于BIM的铁路路基三维建模方法研究

对基于Bentley平台的铁路路基三维建模方法展开探索和研究:(1)对路基建模方法的研究现状进行总结,认为基于网格和参数化的建模方法较为适用。(2)根据路基结构的造型特点,将路基结构物分为线状构造物和不连续构造物。(3)连续线状构造物建模主要分两步,一是通过编辑横断面构建路基骨架,二是采用放样、拉伸横断面的方式构建路基网格模型,再通过三维可视化检查模型的合理性。(4)对于不连续构造物,如挡土墙、地基处理桩等构件,应采用参数化的建模方法。     

Development of control models for the planning of sustainable transportation systems

Planning of sustainable transportation systems requires integration of multiple systems while considering a holistic approach. A limited amount of research has been conducted that simultaneously considers all the transportation, economic activity, environmental and social effects. The proposed research envisages incorporating considerations related to sustainability and providing solutions to stakeholders in policy making. In this paper, a dynamic model for planning and development of sustainable transportation systems is presented. This is given by a system of three nonlinear differential equations representing the dynamics of the three independent states, namely, transportation, activity, and environmental systems. A policy scenario considering investment in energy efficient technologies and its effects on the states is discussed to assist making investment decisions. Optimal control techniques are used to design the controls. The results show that it is possible to formulate an optimal control to achieve the desired target. Numerical results, based on actual parameters, are presented to illustrate the long-term trends of the states. The methodology discussed in this paper will be helpful to decision makers in making optimal decisions. The contribution of this research work is the introduction of a systems and controls methodology to develop optimal policies for the design of sustainable systems.     

组织及其"贫"信息建模方法

管理科学研究的对象是组织.组织是复杂的人机系统.组织的外部信息输入是设置组织的基准输入和全局目标的依据.现实组织的外部信息输入通常处于"贫"信息状况.本文提出基于相似关联分析的"贫"信息建模方法,同时据此构建一种SCGMsmv(1,1)模型.示例表明该模型精度高、计算量少,具有良好的应用前景.     

关于民航应急保障预案的思考

在论述加强民航应急输送保障预案研究重要意义的基础上,阐述了民航应急输送保障的新特点,拟制民航应急输送保障预案的要求,探讨了应付突发事件民航应急输送保障预案的内容及处置办法。为保证民航在应付突发事件中顺利实施部队应急输送提供理论依据与技术支持。     

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加拿大阿尔伯塔省经济的飞速发展，使得为全省制定合理的交通规划成为一项迫切的任务，在这种情况下，本文提出了全省的土地利用交通模型。该模型以PECAS（生产、交易和消费分派系统）结构为基础，实质是在整体经济的前提下考虑基本的交通需求（商品、服务、劳动力交换的流通过程）而进行交通规划。生产、交易和消费分派系统是一种空间经济模拟系统，它侧重交通规划和发展规划，近几年在美国提出并在一些州和城市得到应用。阿尔伯塔省土地利用交通模型受其模型建立基础，尤其是MEPLAN 和TRANUS模型的影响，但该模型在理论基础和行为描述上都做了明显的改进。本文从数据源和标定方法方面介绍加拿大阿尔伯塔省的土地利用交通模型的建立和发展。     

道路三维场景的实时动态显示技术

实时动态显示技术是实现道路三维可视化设计的关键，应用Delaunay三角化算法构建数字地面模型，基于分割—归并思想完成道路三维实体造型，在此基础上，提出并实现了有效的道路三维模型的视相关简化算法，并结合真实感图形绘制技术开发了道路三维场景的实时动态浏览平台，将该平台与路线CAD系统集成，实现了道路设计过程和设计成果的可视化。     

机器人的三维运动仿真

通过对一个机器人机械手三维实时运动仿真系统实例的介绍和分析，阐述了利用OpenGL图形库实现机器人运动仿真的有效方法，重点分析了机器人运动学模型的构建及仿真过程的动态显示，并且讨论了该仿真系统的主要功能模块构成。最后总结了该仿真系统的主要特点，指出了OpenGL在机器人运动仿真中的应用前景。     

数控车床仿真系统开发

根据数控车削加工的特点，提出一个基于构造单元的工件分解表达模型，利用此模型与刀具实体模型做布尔减运算，实时模拟工件材料的去除加工过程，并验证加工结果．在此基础上，根据切削力、切屑形成原理，提取几何仿真中的切削层参数和一些相关参数，将其应用于切削力计算和切屑仿真中，形成几何仿真和物理仿真集成的数控车床仿真系统．