滚装甩挂运输牵引车调度优化及作业模式类比分析

针对滚装甩挂运输新船型可“直进直出”条件下的“边装边卸”作业模式，与传统船型“船艉 进出”条件下的“先卸后装”作业模式对比，建立滚装甩挂码头牵引车调度的混合整数规划模型， 并设计遗传算法求解模型。通过对比不同规模算例下CPLEX与所设计遗传算法的实验结果，验证模型的正确性和算法的有效性。结果表明：相较于传统船型“先卸后装”作业模式，新船型“边装边卸”作业模式在运营成本方面可降低约15%；当装卸任务分布密集时，卸船任务靠近船艏运营成本越高，装卸任务分布稀疏时，卸船任务远离船艏运营成本越高；总体而言，“边装边卸”作业模式的运营成本低于“先卸后装”作业模式。研究结论可为“边装边卸”作业模式下的港口滚装甩 挂作业调度提供决策支持。     

需求变动下高铁快运货流分配与组织模式优化

基于高铁快运一地集货和多点发运的开行特点，综合考虑我国未来快递市场的需求变动，提出高铁快运常态化和规模化成网运营后的货流分配与组织模式优化方法，以客运动车组捎带运输货物、预留车厢和高铁快运专列模式下，各OD对间的高铁快运运量为主要决策变量，以总运输成本极小化为目标，构建货流分配混合整数规划模型，计算货流量在高铁快运网络中的分布，得到货流OD运输路线与各高铁快运通道运营组织模式的组合优化方案。通过高铁快运货流OD “三阶段”预测方法，预测城市间的高铁快运需求量作为货流输入，以9个国内快递业务中心城市组成的网络为案例，由Python语言调用Gurobi优化软件求解案例，验证所建模型的有效性。案例结果表明：在运量低谷期使用捎带和预留模式可满足90.7%的运输需求；在运量高峰期部分线路需开行高铁快运专列；运营组织模式可根据OD对间货流量与网络容量的适应性关系进行调整，以充分利用高铁闲置运力，提升运营效益。     

基于关键链技术在装备维修项目进度管理中的应用研究

根据装备维修工程进度管理的现状,分析传统的关键路径技术(CPM)方法的主要问题,总结计划进度管理方法的优缺点,提出将考虑资源约束的进度管理方法-关键链技术应用于装备维修工程进度管控,运用约束理论和缓冲优化方法对具体工程项目进行进度计划调整与修理工期优化,并通过和CPM方法结果的比较分析,得出关键链技术可以更科学合理制定装备维修项目进度计划并达到优化修期的目的,为装备维修进度管理提供理论与实践参考。     

Online channel strategies under different offline channel power structures for the Belt and Road of China

ABSTRACT

This paper explores the online channel strategies adopted by Chinese manufacturers with regard to the Belt and Road. It also investigates the effect of offline channel power structures and maritime transportation costs on online channel mode selection and pricing strategies. The offline channel power structures are classified into three types, namely, Chinese manufacturer Stackelberg (MS) structure, vertical Nash (VN) structure, and foreign retailer Stackelberg (RS) structure. Furthermore, a game model is developed among the Chinese manufacturer, foreign retailer, and cross-border e-tailer to investigate the interactions among offline channel power structures, maritime transportation costs, and Chinese manufacturers’ online channel mode selection. The results show that Chinese manufacturers’ preferences for the online agency selling mode increases correspondingly with the decrease in their market position and bargaining power. Moreover, foreign retailers can obtain higher profits in the online agency selling mode under the VN structure. However, the level of profit for foreign retailers depends on the intensity of their competition with cross-border e-tailers under the MS and RS structures. Finally, consumers in countries along the Belt and Road can obtain a higher surplus in the online agency selling mode under all of the structures.     

澜沧江航道建设工程溪口滩航道整治方案

以澜沧江Ⅳ级航道建设工程溪口滩航道整治为依托，针对溪口滩整治过程中需要提升航道等级、维持航槽稳定的问题，从溪口滩水沙运动规律、历史整治情况、来水来石特征等方面分析不同溪口滩险形成原因，提出修建拦石坝、溪口导流坝以及常年维护疏浚等治理措施，以达到提升航道尺度并维持航道稳定的目的。结果表明，在山区河流溪口滩航道整治过程中采用拦、导、疏等工程措施，能够解决溪口滩险碍航成滩的难题，可为类似工程提供参考。     

新型DC 600 V列车供电系统输出电压振荡解决方案

新一代复兴号动力集中动车组列车供电柜,首次采用二电平PWM整流器输出DC 600 V为客车供电。由于负载前端串联EMI滤波器,在负载投入时供电柜的滤波电感和EMI电容发生振荡,引起输出电压振荡。文章为抑制输出电压振荡,对输出端并联RC吸收电路和滤波电感并联RC两种方案分别进行讨论和验证,通过对主电路结构分析,认为滤波电感并联吸收电阻方案为最优。最后通过仿真和试验验证所提方案的可行性和有效性。     

梯级电站变动回水区设计最低通航水位确定方法

梯级电站变动回水区受上游电站下泄流量与下游坝前水位双重影响,设计最低通航水位的确定十分复杂。传统的设计最低通航水位保证率主要对流量进行统计,指标不够全面;而且设计最低通航水位计算工况组合的选取具有一定的偶然性,实际设计过程中可操作性不强。提出入库流量与坝前水位组合保证率计算方法,该方法综合考虑了入库流量与坝前水位遭遇组合的概率。利用该方法可合理确定梯级电站变动回水区设计最低通航水位,同时结合电站调度方案,在电站可接受的调度方式下,投入最少的资金对航道进行整治,以达到最优的效果。     

SiC功率器件在轨道交通行业中的应用

为解决轨道交通牵引及辅助系统的轻量化等问题,宽禁带半导体器件如SiC器件的应用需求越来越大。SiC材料具有禁带宽度大、击穿场强高、电子饱和漂移速率快等特性,能满足在中大功率、高温、高频条件下工作的应用要求。简述了SiC器件相比传统硅基器件的突出优势及商业化和实验室研发情况,介绍了SiC功率器件在轨道交通行业中的发展现状,同时对其在未来轨道交通装备业的发展提出了建议和展望。     

Integrated planning of static and dynamic charging infrastructure for electric vehicles

This paper investigates the optimal deployment of static and dynamic charging infrastructure considering the interdependency between transportation and power networks. Static infrastructure means plug-in charging stations, while the dynamic counterpart refers to electrified roads or charging lanes enabled by charging-while-driving technology. A network equilibrium model is first developed to capture the interactions among battery electric vehicles’ (BEVs) route choices, charging plans, and the prices of electricity. A mixed-integer bi-level program is then formulated to determine the deployment plan of charging infrastructure to minimize the total social cost of the coupled networks. Numerical examples are provided to demonstrate travel and charging plans of BEV drivers and the competitiveness of static and dynamic charging infrastructure. The numerical results on three networks suggest that (1) for individual BEV drivers, the choice between using charging lanes and charging stations is more sensitive to parameters including value of travel time, service fee markup, and battery size, but less sensitive to the charging rates and travel demand; (2) deploying more charging lanes is favorable for transportation networks with sparser topology while more charging stations can be more preferable for those denser networks.     

无人救助艇的动力与控制系统选型

基于无人救助艇的性能要求,重点介绍动力与控制系统选型过程和原因。该艇选择磷酸铁锂电池为电源,并采用全电力推进、远程无线遥控控制技术。该无人救助艇的应用,增添了海洋救助方式。