采用多体系统动力学的平衡悬架牵引车平顺性研究

采用多体系统动力学理论及相应软件ADAMS，对具有平衡悬架的3轴牵引车平顺性进行研究。建立了其多体系统动力学模型，并经过二次开发形成一套能够进行参数化自动建模的软件系统。对仿真模型进行时域、频域的仿真分析，并研究平衡悬架的一些主要设计参数对平顺性的影响。     

Network effects of intelligent speed adaptation systems

Intelligent Speed Adaptation (ISA) systems use in-vehicle electronic devices to enable the speed of vehicles to be regulated automatically. They are increasingly appreciated as a flexible method for speed management and control particularly in urban areas. On-road trials using a small numbers of ISA equipped vehicles have been carried out in Sweden, the Netherlands, Spain and the UK. This paper describes the developments made to enhance a traffic microsimulation model in order to represent ISA implemented across a network and the impact of this on the networks. The simulation modelling of the control system is carried out on a real-world urban network, and the impacts on traffic congestion, speed distribution and the environment assessed. The results show that ISA systems are more effective in less congested traffic conditions. Momentary high speeds in traffic are effectively suppressed, resulting in a reduction in speed variation which is likely to have a beneficial impact on safety. Whilst ISA reduces excessive traffic speeds in the network, it does not affect average journey times. In particular, the total vehicle-hours travelling at speeds below 10 km/hr have not changed, indicating that the speed control had not induced more slow-moving queues to the network. A statistically significant, eight percent, reduction in fuel consumption was found with full ISA penetration. These results are in accordance with those from field trials and they provide the basis for cost-benefit analyses on introducing ISA into the vehicle fleet. However, contrary to earlier findings from the Swedish ISA road trials, this study suggested that ISA is likely to have no significant effect on emission of gaseous pollutants CO, NO_x and HC.     

竞争性运输通道选择的博弈模型研究

通过对博弈论原理和竞争性运输通道选择问题的特性的研究,可以用博弈论的方法和原理比较和选择竞争性运输通道。在对竞争性运输通道的选择问题进行抽象的数学描述后,建立了相应的博弈论数学模型,并运用剔除严格劣战略的方法,对模型构造了可行的算法。同时对参与人集合的确定;纳什均衡的个数以及模型的拓展等问题做了进一步的分析.最后,通过与AHP的比较,提出了模型向贝叶斯博弈拓展的设想。为竞争性运输通道的选择优化问题提供了一种新的研究思路.     

《交通微观仿真分析指南》概要

近年来,交通规划软件所使用的方法从对交通量的宏观分配转变为对单个车辆的微观仿真.这一方法论的改变意味着需要对委任交通工程项目、项目管理以及对其结果进行解释等的职能部门的指导方针进行更新,以便能反映微观仿真的独特能力.与之前的模型相比,微型仿真能够更完整和详细地反映道路交通状况的内在变化.位于苏格兰的SIAS交通规划咨询公司就此编写了《微观仿真最佳咨询项目指南》和《交通微观仿真分析指南》,以帮助交通从业人员从事微观仿真项目和解释其结果.这些指导方针是基于该公司进行项目咨询和开发S-Paramics微观仿真软件的经验基础上编写而成的.     

物资企业经营计划优化模型研究

结合物资企业的经营特征,通过对经营计划制定过程的分析,给出了多品种、价格有折扣、市场需求随机、经营方式灵活的物资经营计划优化模型及求解方法,并对模型的适应性进行了讨论。因模型的建立与物资企业的实际情况相适应,所以对物资企业经营有较大的指导意义。     

考虑溢流费用的路径选择模型的条件研究

通过考虑路段的溢流费用,即路段交通负荷超过该路段交通负荷标准时所分配给用户的费用。路段交通负荷低于路段负荷标准时补贴给用户。建立一些约束条件,动态用户最优的路径选择条件和动态用户最优的溢流费用条件等。为进一步建立具有溢流费用的动态交通网络流的路径选择变分不等式模型及其算法研究打下基础。     

The influence of upwelling and entrainment on the algal bloom in the Baltic Sea

Hydrodynamic processes control many geochemical and ecological processes in the sea. In this paper, the influence of up- and downwelling and entrainment on the ecosystem components are studied. The ecohydrodynamic model was initially used to simulate the whole Baltic Sea to get the boundary conditions for the Gulf of Riga. Then, to study the influence of different hydrodynamic conditions on the algal bloom, three simulations were made for the Gulf of Riga using different boundary and entrainment conditions. It appears that upwelling in the gulf was strongly dependent on open boundary conditions between the Baltic Proper and the gulf. The vertical transport in the Gulf of Riga was many times more intensive in the calculation system Baltic Proper and Gulf of Riga, than in the case where only the Gulf of Riga was simulated. The blue–green algal bloom was influenced by the vertical transport due to different nutrients' limitation mechanism.     

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 commuting model for the analysis of the impacts of a tramway project: application to the Lens area

Road congestion is not only an issue for major European urban agglomerations, but also for smaller ones. It is also the case of the Lens urban area, where car use is much higher than the average for medium-sized urban agglomerations in France. Local authorities put forward tramway projects to deal with the strongly negative externalities of congestion: travel time losses and pollution. To analyse its medium-term impact, we have developed a commuting with congestion model, inspired by the four-step traditional model, but with data made available from an origin–destination matrix. The results are encouraging but insufficient, and it is necessary to adopt supplementary measures in order to retrieve and justify the sizeable investments needed. Some measures prove to be very efficient, such as parking fees and urban tolls. Other measures, such as the subsidization of public transport, are partially efficient since they have an impact mainly on intra-urban commutes.