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Seung Hyun Kim 《运输规划与技术》2016,39(6):574-585
The delivery service provided by large-scale retailers continues to grow as online sales occupy an increasingly large share of the market. This study aims to tease out efficient vehicle scheduling times as well as optimal delivery routes by applying meta-heuristic algorithms. Monthly data on existing routes were obtained from a branch of Korea’s leading large-scale online retailer. The first task was to examine the status of existing routes by comparing delivery routes created using Dijkstra’s algorithm with existing delivery routes and their vehicle scheduling. The second task was to identify optimal delivery routes through a comparative analysis of the genetic algorithm and Tabu search algorithm, known for its superior applicability amongst other meta-heuristic algorithms. These findings demonstrate that the optimal vehicle routing problem not only has the potential to reduce distribution costs for operators and expedite delivery for consumers, but also the added social benefit of reduced carbon emissions. 相似文献
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E. J. Bernal R. M. Martinod G. R. Betancur 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2016,54(5):606-616
The present work poses a method for the measurement of geometric parameters of rail wheels in a dynamic condition, by reconstructing the profilogram from a portion of the wheel surface wear with artificial vision. The suggested procedure can work with a two-dimensional laser displacement transducer or by processing a sole image from a single camera with a structured light source. These two procedures require fewer devices and simpler implementation processes and allow the use of mathematical algorithms that demand less information processing, thus generating more accurate results. Railway operators may implement this method to perform predictive maintenance to their rolling stock at a fraction of the regular cost; thus achieving better precision, availability, maintenance performance and improving safety. Results were compared to those given by commercial equipment, showing similar precision but a better cost–benefit relation. 相似文献
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文章从高铁时代下高铁运输对传统道路运输的冲击入手,结合区域经济发展情况,分析道路运输企业所面临的挑战和发展机遇,探讨了高铁与道路客运的优劣性,提出道路客运企业应对挑战、走出困境、持续发展的对策。 相似文献
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以渔家乐滚塑休闲船为例,考虑船艇体的弹性形变、随机风速和随机波浪等非线性因素,采用时历图、相图、功率谱和Lyapunov指数从不同角度剖析船艇横摇中的动力学特性,然后应用精确反馈线性化和闭环增益成形算法相结合的方法设计控制器,使船艇脱离混沌状态。仿真结果表明:当计及船体弹性形变时,横摇频率加快,角速度和角加速度均增大,船艇稳性和舒适感变差;随着风和浪所含谐波次数的增加,横摇更加剧烈,混沌现象愈显著;所设计的控制器能够有效控制其混沌,从而达到增加船艇安全性、稳定性和舒适性的目的。 相似文献
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围绕《道路运输车辆动态监督管理办法》的实施,本文在调研道路运输企业动态监控系统应用情况基础上,分析动态监控工作中存在的问题和原因,提出规范动态监管工作的对策。 相似文献
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This study investigates the time-dependent reliable shortest path problem (TD-RSPP), which is commonly encountered in congested urban road networks. Two variants of TD-RSPP are considered in this study. The first variant is to determine the earliest arrival time and associated reliable shortest path for a given departure time, referred to as the “forward” TD-RSPP. The second problem is to determine the latest departure time and associated reliable shortest path for a given preferred arrival time, referred as the “backward” TD-RSPP. It is shown in this article that TD-RSPP is not reversible. The backward TD-RSPP cannot be solved by the algorithms designed for the forward problem using the reverse search from destination to origin. In this study, two efficient solution algorithms are proposed to solve the forward and backward TD-RSPP exactly and the optimality of proposed algorithms is rigorously proved. The proposed solution algorithms have potential applications in both advanced traveler information systems and stochastic dynamic traffic assignment models. 相似文献
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