BTM辐射模式估计研究

在“轨道交通控制与安全”国家重点实验室应答器分析测试平台的基础上，参照UnisigSubset085规范，对测试应答器传输模块的辐射模式估计进行了xml语言规范描述，并基于Labwindows／CVI虚拟仪器开发环境，对测试系统中辐射模式估计功能进行实现，对模块的性能作出正确的评价有重要的指导意义。     

Dynamic activity-travel assignment in multi-state supernetworks

The integration of activity-based modeling and dynamic traffic assignment for travel demand analysis has recently attracted ever-increasing attention. However, related studies have limitations either on the integration structure or the number of choice facets being captured. This paper proposes a formulation of dynamic activity-travel assignment (DATA) in the framework of multi-state supernetworks, in which any path through a personalized supernetwork represents a particular activity-travel pattern (ATP) at a high level of spatial and temporal detail. DATA is formulated as a discrete-time dynamic user equilibrium (DUE) problem, which is reformulated as an equivalent variational inequality (VI) problem. A generalized dynamic link disutility function is established with the accommodation of different characteristics of the links in the supernetworks. Flow constraints and non-uniqueness of equilibria are also investigated. In the proposed formulation, the choices of departure time, route, mode, activity sequence, activity and parking location are all unified into one time-dependent ATP choice. As a result, the interdependences among all these choice facets can be readily captured. A solution algorithm based on the route-swapping mechanism is adopted to find the user equilibrium. A numerical example with simulated scenarios is provided to demonstrate the advantages of the proposed approach.     

Application of Lagrangian relaxation approach to α-reliable path finding in stochastic networks with correlated link travel times

This study investigates the important problem of determining a reliable path in a stochastic network with correlated link travel times. First, the distribution of path travel time is quantified by using trip records from GPS probe vehicles. Second, the spatial correlation of link travel time is explicitly considered by using a correlation coefficient matrix, which is incorporated into the α-reliable path problem by Cholesky decomposition. Third, the Lagrangian relaxation based framework is used to handle the α-reliable path problem, by which the intractable problem with a non-linear and non-additive structure can be decomposed into several easy-to-solve problems. Finally, the path-finding performance of this approach is tested on a real-world network. The results show that 15 iterations of calculation can yield a small relative gap between upper and lower bounds of the optimal solution and the average running time is about 5 s for most OD settings. The applicability of α-reliable path finding is validated by a case study.     

道路网络服务水平可靠性研究

以可靠性理论为基础,从出行者个体和网络管理者的角度提出了服务水平可靠性的概念,拓展了现有的路网可靠性评价指标.根据交通供给的随机性分析,将路段容量简化为离散随机变量,运用路网最可能状态生成算法,建立了路段及路网服务水平可靠性计算的近似算法,并在一简单网络上进行了计算分析.     

基于关键路段的路网可靠性的改进

为简化资源约束下路网可靠性的改进问题，只选择关键路段（即被选择的概率大于预定阀值的路段）进行改进．由于出行者在事件（例如地震、洪水、飓风等）前后的路径选择行为用弹性需求随机用户平衡刻画，路段的选择概率可以基于路段水平有效求得，因而容易确定关键路段．建立了以路网净经济效益相关的可靠性最高为目标，并有资源约束的数学模型．提出了模型的一种启发式算法．算例的结果表明了该方法的有效性．     

地铁车-地无线通信引入LTE后的干扰分析

针对国内地铁的车-地无线通信技术,将LTE(long term evolution,长期演进)与WLAN(wireless local area networks,无线局域网)技术进行对比,提出一套LTE组网方案。针对该方案,分析下行链路预算,对LTE基站的覆盖能力进行评估,认为引入LTE后,地铁中覆盖了多频段的无线通信系统;由于系统间频率相近,无线信号之间容易形成干扰。从干扰形成的角度分析干扰的成因,定量计算系统间的隔离度,从技术和工程建设角度给出减少干扰的措施。     

航空轨道线运营衔接规划模型

航空轨道线是连接机场陆侧与市区、为集散机场地面交通服务的轨道交通线,是充分发挥航空运输快捷的重要交通方式.为减少乘客利用航空轨道线进行换乘时的等待时间,建立了航空轨道线运营衔接规划模型,以乘客换乘时间最小为目标函数,考虑了轨道交通的容量限制,并对模型进行求解,得到其最佳发车时间间隔.     

山区高速公路桥隧相连技术的研究与应用

通过研究山区高速公路隧道洞口桥隧相连的有关技术及其在实际工程中的合理选择与应用,分析其优缺点,并总结经验,对类似条件下桥梁与隧道的建设具有一定的指导意义。     

机车牵引杆座细部结构设计及计算分析

以SS7型电力机车牵引杆座为例,对机车牵引杆座的细部结构进行了设计及计算分析．建立了9种计算模型,研究了细部结构设计对结构强度的影响．提出了刚度协调性对结构强度影响的重要性。     

基于响应时间的时隙需求与仿真分析

响应时间是描述数据链网络实时性以及分析网络能否满足作战要求的重要指标,其大小与分配的时隙数量有关。文章针对随机性消息的特点,运用排队论研究了时分多址数据链网络满足实时性要求的时隙需求,并构建了作战平台消息的产生、排队等候及发送过程的仿真模型。结果表明,理论计算与仿真结果得到的平均响应时间基本吻合,但仿真显示,不同消息的响应时间相差较大,有些消息甚至不能满足作战要求。所以,时隙需求数量必须进行仿真验证并据此进行调整,以获得最佳的分配方案。文章给出的时隙需求分析理论及仿真平台能用于数据链网络设计及仿真验证工作。