Optimizing multi-agent based urban traffic signal control system

Agent-based approach is a popular tool for modelling and developing large-scale distributed systems such as urban traffic control system with dynamic traffic flows. This study proposes a multi-agent-based approach to optimize urban traffic network signal control, which utilizes a mathematical programming method to optimize the signal timing plans at intersections. To improve the overall network efficiency, we develop an online agent-based signal coordination scheme, underpinned by the communication among different intersection control agents. In addition, the initial coordination scheme that pre-adjusts the offsets between the intersections is developed based on the historical demand information. Comparison and sensitivity analysis are conducted to evaluate the performance of the proposed method on a customized traffic simulation platform using MATLAB and VISSIM. Simulation results indicate that the proposed method can effectively avoid network oversaturation and thus reduces average travel delay and improves average vehicle speed, as compared to rule-based multi-agent signal control methods.     

战略装车点选址模型研究

分析了建立区域战略装车点的政策性原则和关联因素,并根据铁路运输生产实际模拟了在供需均衡条件下选站建点系统架构,构建战略装车点多点选址多类变量混合0-1非线性规划模型(MSLSLP)。模型以社会总成本最小化为出发点,协同考虑决策者和客户双方利益,将选站建点的改扩建费用、可变费用和代表客户利益的运输成本共同纳入目标体系。将建立战略装车点后的运输特点要求与相关选址模型的共性约束相结合构造约束条件,使其更具针对性。最后,以相当规模数值算例验证了模型的有效性和可行性。     

城市道路交通对汽车产业的影响

近年来随着城市道路交通的发展,汽车产业在中国飞速发展,取得了辉煌的成就。汽车产业与城市道路交通之间有着密切的关系,城市道路交通的完善对汽车产业具有巨大的促进作用。本文以每年的汽车总销量为因变量,以城市道路长度和城市道路面积为主要自变量,通过建立线性回归模型来分析城市道路交通对汽车产业的影响,并对未来汽车产业的发展作出有根据的预测,为企业和政府制定汽车产业发展计划提供了一定的依据。     

Suppression of thrust fluctuation of doubly-fed linear motor

Because the mover and stator of a doubly-fed linear motor are both equipped with three-phase windings,the motor enables contactless energy to be transferred from the stator to the mover.Thus,when a dou...     

The impacts of strait and canal blockages on the transportation costs of the Chinese fleet in the shipping network

ABSTRACT

Straits and canals have always served as key nodes in shipping networks. The blockage of a strait or canal will lead to ship deviations and increased transportation costs. To measure this impact on the Chinese fleet, our study develops a mathematical model that is based on a programming formulation. Each strait or canal is assumed to be blocked in turn, and the increased transportation costs for the Chinese fleet in different scenarios are calculated and compared using the proposed programming formulation in order to measure the impact of the blocked strait or canal on the Chinese fleet. Larger increases in transportation costs have greater impacts on the fleet. The results show that a blockage of the Strait of Hormuz would have the greatest impact of all straits and canals; it would cause the Chinese fleet to lose a portion of its import and export market, and such a blockage cannot be addressed through ship deviations. Based upon increased transportation costs, the four straits or canals that would have the greatest impact if blocked are the Mandeb Strait, the Suez Canal, the Sunda Strait and the English Channel.     

基于多编组的列车满载率均衡化方法研究

针对多编组均衡发车导致的大小编组列车利用率不均的问题，本文构建了轨道交通多编组列车开行方案双层规划模型.上层模型以大小编组发车频率为决策变量，乘客出行费用和企业运营成本最小为目标；下层模型以列车编组和发车间隔为决策变量，大小编组列车间的满载率均衡程度最大为目标，并设计嵌套遗传算法求解.算例分析表明：当列车编组和发车频率一定时，大小编组列车均衡发车时平均满载率相差 50%，非均衡发车时两者仅相差 0.8%，这说明非均衡发车模式可以有效提高列车满载率均衡性；大小编组列车均衡发车时，列车编组辆数不宜相差过大，非均衡发车时可以通过调整发车间隔的方法提高列车满载率的时空均衡性.     

基于ITS的公共交通换乘等待时间最短调度问题研究

为使公共交通的换乘时间实现最佳衔接,先进的公共交通系统的高效率和优势得以体现,在对各国研究现状分析的基础上,研究了ITS实时提供公共交通信息的条件下,公共交通换乘等待时间最短调度问题。为了对公共交通换乘总等待时间最短目标下的公共汽车发车时刻表确定方法进行分析,应用运筹学理论,分别针对一个换乘点和多个换乘点的情况建立了线性规划模型,并用一个换乘点的算例验证了模型的可行性和有效性。结果表明：该方法能最大限度地减少乘客换乘总等待时间,尤其是对于发车间隔较大的公共交通方式间换乘的时间节约效果更为明显。     

数字摄影测量在交通事故现场勘查中的应用

对于交通事故现场的处理，目前主要使用拉皮尺、目击调查以及使用影像记录等简单的勘查手段，这对需要快速记录现场情况，然后迅速疏通交通，并在事后进行事故分析和责任认定等造成一定的困难。文章将数字摄影测量中的双像立体和单像纠正技术引入现场勘查，通过事后恢复有用的几何信息以及绘制符号化事故现场图，实现事故现场的可视化重现，为事故分析、责任认定和案例存档等提供了有效途径。为说明该方法的可行性和有效性，文中介绍了相关软件，并通过实验证明该技术具备精度高。自动化程度高以及使用简单等特点。     

道路拥挤定价下的公交收费模型研究

为了在执行道路拥挤定价政策的前提下制定公共交通的收费标准，提出可行的定价模型，根据交通行为科学的有关理论和方法，采用了两层规划技术建立了道路拥挤定价下的公交收费模型，上层规划为交通系统优化，下层规划为拥挤定价下的路网随机平衡问题。以广州市为研究对象，计算了拥挤定价下广州市公交线网的最优价格体系。研究结果表明：所提出的模型能够描述出行者和交通管理部门分别在出行和交通管理中的决策行为，较好地解释了用户平衡、路段路径流量和阻抗、交通需求、拥挤费、公交票价、出行成本等相互之间的逻辑关系。