一种移动自组网多径QoS路由协议

在分析多径路由技术的基础E,提出了一种基于AODV的多径QOS路由协议AODVMQR.该协议采用了降低开销和时延的机制、多径路由机制和移动预测的思想,并提供了QoS保障.仿真结果表明,该协议减少了路由开销,提高了分组传输率,降低了时延,改善了网络的服务质量.     

Intermodal route selection for cargo transportation from Korea to Central Asia by adopting Fuzzy Delphi and Fuzzy ELECTRE I methods

Due to the increase in trade from Korea to Central Asia, an efficient intermodal route for transporting cargo is important. Intermodal routing for long-distance transportation faces operational challenges, such as customs clearance, track gauge differences, and climate limitations. The initiative of the Silk Road Economic Belt recently proposed in China could improve trade and transport links in Asia and create an efficient transportation route that focuses on the railroad service provided in China. The objective of this study is to obtain an evaluation structure for intermodal routing and then find the route for transporting cargo from Korea to Central Asia under China’s Silk Road Economic Belt with integrated Fuzzy Delphi and Fuzzy (Elimination Et Choice Translating Reality (ELECTRE) I methods. After a sensitivity analysis is performed, development strategies and alternative routes are suggested. The results show that among the five principal factors, total cost is the most important factor for logistics companies when they select a transportation route, followed by reliability, transportation capability, total time, and security. Of the sub-factor weights, transportation costs and cooperation and emphasis among state organization are important. In the intermodal route results, route 3, Incheon to Qingdao to Horgos to Almaty, is preferred.     

Routing and charging locations for electric vehicles for intercity trips

This study addresses two problems in the context of battery electric vehicles (EVs) for intercity trips: the EV routing problem and the EV optimal charging station location problem (CSLP). The paper shows that EV routing on the shortest path subject to range feasibility for one origin–destination (O–D) pair, called the shortest walk problem (SWP), as well as a stronger version of the problem – the p-stop limited SWP – can be reduced to solving the shortest path problem on an auxiliary network. The paper then addresses optimal CSLPs in which EVs are range feasible with and without p-stops. We formulate the models as mixed-integer multi-commodity flow problems on the same auxiliary network without path and relay pattern enumeration. Benders decomposition is used to propose an exact solution approach. Numerical experiments are conducted using the Indiana state network.     

城市轨道交通线网检测车路径优化

针对目前轨道检测车作业路径缺乏系统规划方法的弊端,以城市轨道交通线网为背景,构建成网条件下多约束地铁大型检测车辆路径优化模型(urban track inspection vehicle routing problem,UTIVRP)。针对地铁线网的特点,设计具有特殊编码方式的文化基因算法,并通过北京地铁实际算例予以验证。计算结果表明,在满足既定检测要求的情况下,优化方案不仅能够减少车辆48.88%的空走里程,而且能够将线网的检测间隔最大偏差率降低93.33%。     

动态车辆路径问题的遗传算法研究

文章针对动态车辆路径的特点及模型对其算法进行了研究,并设计了改进的遗传算法对最优路径进行求解,结果显示采用改进的遗传算法提高了全局寻优能力与收敛速度,取得了较好的效果。     

考虑满载率均衡性的大小交路列车开行方案优化研究

多交路列车开行方案的优化编制是城市轨道交通网络化运营面临的重要课题.根据大小交路列车运行特点,本文构建大小交路列车开行方案双层规划模型.上层模型考虑小交路区段乘客乘车选择偏好对列车客流分担比例的影响,以乘客等待时间、车辆走行公里和列车运行时间最小化为目标,以小交路折返站、发车频率及大小交路的发车比例为决策变量;下层模型以大小交路列车间满载率的均衡程度最大为目标,以列车编组辆数和发车间隔为决策变量.算例结果表明,采用"大交路大编组,小交路小编组"可以提高大小交路列车间满载率的均衡性;考虑满载率均衡性时,早晚高峰大小交路列车间平均满载率差值分别减小21.5%和17.9%;调整列车发车间隔和缩短小交路列车编组2种方法均可以提高满载率的均衡性.     

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在详细分析遗传算法的局限性的基础上，构造了一种基于遗传算法和禁忌搜索算法相结合的、用于求解车辆路径问题的混合遗传算法。这种混合遗传算法主要是将禁忌搜索算法嵌入到遗传算法中的变异操作与最优解判定之间，可以有效地避免遗传算法易出现“早熟”收敛的问题。然后，分别用混合遗传算法和遗传算法对同一实例进行求解，并对求解结果进行对比分析。结果表明该混合遗传算法的求解结果比遗传算法收敛速度快，更加接近最优解。     

无线多媒体传感器网络的QoS路由算法

作为一种全新的信息获取和处理技术,无线多媒体传感器网络较之传统传感器网络更多地关注于音频、视频、图像等大数据量、大信息量媒体的采集与处理,在军事、民用及商业领域中具有广阔的应用前景.文中针对具有Mesh结构的无线多媒体传感器网络,给出了其带宽、时延和时延抖动等多约束的QoS路由问题模型的描述.基于基本遗传算法提出了一种多约束的QoS路由算法,给出了算法的具体实现流程,并对算法的收敛性和路由成功率等进行了实验仿真.     

基于定长帧的组播QoS路由技术

为高效利用网络资源且平衡负载,结合物理帧时槽交换技术,提出了基于定长帧的组播机制和QoS路由算法MRBP.该算法在满足带宽和时延要求的基础上,最小化时延和平衡节点负载,达到组播树总体时延较小并优化利用网络资源的目的.仿真结果表明,基于该算法建立的组播树具有较好的网络负载平衡性,并能够对服务质量提供较好的保证.