Surrogate‐based optimization of cordon toll levels in congested traffic networks

The benefit, in terms of social surplus, from introducing congestion charging schemes in urban networks is depending on the design of the charging scheme. The literature on optimal design of congestion pricing schemes is to a large extent based on static traffic assignment, which is known for its deficiency in correctly predict travel times in networks with severe congestion. Dynamic traffic assignment can better predict travel times in a road network, but are more computational expensive. Thus, previously developed methods for the static case cannot be applied straightforward. Surrogate‐based optimization is commonly used for optimization problems with expensive‐to‐evaluate objective functions. In this paper, we evaluate the performance of a surrogate‐based optimization method, when the number of pricing schemes, which we can afford to evaluate (because of the computational time), are limited to between 20 and 40. A static traffic assignment model of Stockholm is used for evaluating a large number of different configurations of the surrogate‐based optimization method. Final evaluation is performed with the dynamic traffic assignment tool VisumDUE, coupled with the demand model Regent, for a Stockholm network including 1240 demand zones and 17 000 links. Our results show that the surrogate‐based optimization method can indeed be used for designing a congestion charging scheme, which return a high social surplus. Copyright © 2016 John Wiley & Sons, Ltd.     

基于极点配置的海洋平台粘弹性阻尼振动控制

对随机波浪激励的多自由度海洋平台模型进行动力分析,研究基于粘弹性阻尼器的海洋平台振动控制及阻尼器的位置优化,提出使用极点配置技术实现粘弹性阻尼器的优化定位;粘弹性阻尼器采用开尔文模型,将其对结构的作用看作是位移和速度的反馈控制.针对一海洋平台计算模型,在随机波浪载荷作用下进行平台振动响应分析及阻尼器的位置优化设计,结果表明采用极点配置技术设置粘弹性阻尼器,平台位移和加速度响应得到有效控制.     

出行策略与行程时间不确定下的公交客流分配方法

利用杭州市公交线路站点GIS数据和车辆运行GPS数据进行分析,将公交车到站时间分为站点停靠时间和站间行程时间,得到公交车站点之间运行可能总时间的分布概率.通过实际的公交路网结构,定义扩展的公交网络有效路径.在考虑公交线路联合发车频率和根据乘客路径选择的广义成本下,建立出行策略与行程时间不确定下的公交客流分配模型,并将公交线路发车时刻表引入用户均衡模型中,设计了基于扩展网络最短路的Method of Successive Average(MSA)算法求解,通过对两个交通小区间高峰小时的客流分配结果验证模型和算法的有效性.     

一种改进的遗传算法在动态交通分配中的应用

以遗传思想为基础设计了新的启发式优化算法,针对动态交通分配问题,对遗传操作中的选择、交叉、变异算子进行修改,同时采用了模拟退火收敛准则,克服了传统遗传算法早熟收敛的弊端,并提高了全局寻优能力。仿真实验表明,该算法有快速高效的特点,提高了该动态交通分配模型的实用价值。