瓯江河口挟沙力公式研究

借鉴两种河口区常见的公式形式,考虑到挟沙力主要与水流流速u,水深h,泥沙沉降速度ω,以及重力加速度g有关.进而运用峰值法、半潮平均及全潮平均法处理瓯江口1999年以及2005年水文实测资料,并用不同方法对资料进行处理后,分别作出垂线平均含沙量S随v2/(gh)和v3/(ghw)的变化图,进行相关分析,得出在全潮平均时S与v2/(gh)的相关系数最好.最后用matlab进行回归分析,得到相关系数较好的瓯江河口挟沙力公式.     

基于广州交通模型的交通影响评估方法

介绍了＂基于广州交通模型的交通影响评估方法＂体系,阐述了应用广州交通模型把握研究项目宏观出行特征,并在此基础上建立了细部模型的技术步骤,提出了基于城市整体模型的交通影响评估方法。     

道路危险货物运输企业安全管理问题的探讨

分析了道路危险货物运输企业的发展现状,指出道路危险货物运输企业安全管理存在的不足,提出了加强道路危险货物运输企业安全管理的措施。     

城市轨道交通项目合同全过程管理

轨道交通项目建设机构在建设过程中对整个项目的全过程的合同管理,大致可分为招标策划、资格预审、招标与定标、合同执行、合同总结与后评估、合同管理培训等六大阶段。介绍了每个阶段合同管理的重要性,并提炼出全过程管理中各阶段的关键控制点。     

轨道交通涉外设备系统采购合同条款的设置

在轨道交通工程项目中,设备系统具有投资比重大、系统性强、涉外投标人严谨度高等特点。为帮助国内招标人员全面了解涉外设备系统标合同执行的特点和国际惯例,以便在合同条款的设置上把握主动权,从合同语言、付款方式、交货方式等九大方面对此进行了总结,使之能从源头上加大力度对合同进行全过程控制。     

推动容县农村客运健康快速发展的对策思考

文章结合容县农村客运现状,分析了农村客运发展存在的问题与原因,提出了发展农村客运的对策与保障措施。     

架空裸管冬季输送-5号柴油结蜡溶蜡规律实验

在环境温度较低的冬季输送-5号柴油时,当外界温度低于柴油析蜡点温度时,油品中的蜡晶会析出附着在管壁上,后行油品使其溶解会导致混油段拉长、混油量急剧增加。通过对-5号柴油在低温状态下进行结蜡溶蜡实验,得到-5号柴油在冬季输送时结蜡溶蜡规律。针对南方某石化公司罐区至供销部码头管线的实际情况,分析结蜡溶蜡规律,提出冬季气温低于-5号柴油析蜡点温度时的油品输送方案,为南方某石化公司供销部储运设施及能力整合优化提供依据。     

Designing computable general equilibrium models for transportation applications

This paper presents a review of Computable General Equilibrium (CGE) model applications for spatial economic and transport interaction modelling. This paper has three objectives (1) To deliver an up to date and comprehensive literature review on applications of CGE models in transportation, (2) To analyze the different methodological approaches and their theoretical and practical advantages and disadvantages, and (3) To ultimately provide guidance on designing CGE models for various transportation analyses. The content of the paper is as follows: first, a brief introduction to CGE models is provided. The history of CGE models is traced, ranging from their origins and seminal applications in economics, to their eventual adoption in transportation research. This is followed by a comprehensive review of the application of CGE models to transport projects and policies. Various applications in transportation are reviewed in terms of their intended application, as well as their treatment of space and time. Finally, these applications are contrasted with respect to their methodological approaches, with a close examination of various influential model choices. Here, the essential design choices made within these model applications are explained and debated, to clearly elaborate on the workings of the models and the design choices facing CGE model developers.     

A fuzzy logic-genetic algorithm approach to modelling public transport users’ risk-taking behaviour

This paper seeks to determine the effects of uncertainty in out-of-vehicle times on route choice. Data were collected at two key interchanges in Auckland, New Zealand. Previous work modelled the data using a manual approach to fuzzy logic. This study extends that work by automating the process through defining a black-box function to match the survey data, then employing a genetic algorithm to fine-tune the fuzzy logic model. Results show that automation and the genetic algorithm improve the model’s capability to more accurately predict ridership. The tuning of the membership functions is conducted twice, first using initial fuzzy rules and again after the fuzzy rules have been adjusted to reduce disparity between the output and survey data. The calibrated membership functions provided for operational (transfer waiting and walking time and delay) and physical attributes (safety and seat availability) can be used by practitioners to determine an estimated ridership.     

Modeling risks and uncertainties in residents’ license choice behaviors under a vehicle restriction policy

Understanding residents’ perception and reaction to vehicle restriction policies is significant for transportation management. However, few studies have examined it from a behavioral and disaggregated perspective, particularly from people’s responses to uncertainties in choices, and their consequent behaviors under potential risks. This paper proposes a multi-level nested logit method to model sequential choice behaviors considering uncertainties under a vehicle license restriction policy. Prospect theory is applied, where a novel reference point is proposed based on instances of ‘whether a risk happens’ rather than a hard number which is difficult to obtain in reality. A case study in Guangzhou, China is presented, where a vehicle restriction policy has been applied for three years. Residents’ attitudes and preferences under uncertainties and different risks are revealed, and these factors are significant in predicting people’s future decisions while policy changes.