不同规制条件下出租车静态市场平衡机制分析

出租车作为一种重要的交通方式,能够为出行者提供快捷、舒适和直接的运输服务。世界上各大城市对出租车市场的运营均采用严格的规制,通过控制出租车牌照的发放来控制出租车辆的规模。同时,还规定了出租车费用收取的标准以及服务质量等其他方面的运营标准。为了解出租车市场的平衡机制,结合解析法和博弈论,就出租车市场在竞争市场和垄断市场等市场机制下可能出现的市场行为进行了分析,从而描述了企业和政府在不同规制条件下可能采取的相应行动。     

铁路货运运力图的应用研究

将结合Mapinfo软件的特性,分析其强大的功能,应铁路货运信息化的建设需求,讨论其在铁路货运运力图的应用,以促进"数字铁路"的快速发展.     

引汉济渭工程岭北隧洞TBM利用率分析

为了分析TBM利用率的主要影响因素,统计分析引汉济渭工程岭北隧洞连续掘进2 100 m的围岩特征和掘进记录,确定了导致TBM非正常停机的底事件,建立了TBM非正常停机故障树模型,结果表明出渣系统故障、支护设备故障、刀盘刀具故障和电气故障是导致TBM利用率不高的主要因素。通过TBM利用率及主要故障与场切深指数（Field Penetration Index,FPI）相关性分析,表明节理破碎岩体中TBM利用率与FPI之间不存在明显相关性,出渣系统故障、支护设备故障、刀盘刀具故障与FPI有较强的相关性。分析主要故障发生原因,从设备管理和现场施工管理2个方面提出TBM利用率提高措施。     

地铁环境与设备监控系统可编程逻辑控制冗余技术可靠性与可用性研究

结合西安地铁1号线环境与设备监控系统(BAS)中采用的可编程逻辑控制(PLC)冗余技术,利用可靠性框图模型和马尔可夫模型分析方法 ,对BAS的可靠性和可用性进行分析,得出了评价系统可靠性和可用性的指标及其计算方法。结果表明,采用PLC冗余技术的西安地铁1号线BAS系统具有较高的可靠性和可用性,可满足地铁运营高可靠性的要求。     

带软时间窗的混合车队车辆路线问题的模型和算法研究

将典型的车辆路线问题扩展为综合考虑了客户具有间窗约束和中央仓库拥有多种类型配送车辆的情况。在构造了问题的数学模型后,着重阐述了求解本问题的TS算法设计过程。最后结合适应性记忆过程给出了TS算法的伪代码描述和一个算法。     

A unified-adaptive large neighborhood search metaheuristic for periodic location-routing problems

This paper introduces three variants of the Periodic Location-Routing Problem (PLRP): the Heterogeneous PLRP with Time Windows (HPTW), the Heterogeneous PLRP (HP) and the homogeneous PLRP with Time Windows (PTW). These problems extend the well-known location-routing problem by considering a homogeneous or heterogeneous fleet, multiple periods and time windows. The paper develops a powerful Unified-Adaptive Large Neighborhood Search (U-ALNS) metaheuristic for these problems. The U-ALNS successfully uses existing algorithmic procedures and also offers a number of new advanced efficient procedures capable of handling a multi-period horizon, fleet composition and location decisions. Computational experiments on benchmark instances show that the U-ALNS is highly effective on PLRPs. The U-ALNS outperforms previous methods on a set of standard benchmark instances for the PLRP. We also present new benchmark results for the PLRP, HPTW, HP and PTW.     

A decomposition approach to determining fleet size and structure with network flow effects and demand uncertainty

This paper presents a new methodology to determine fleet size and structure for those airlines operating on hub‐and‐spoke networks. The methodology highlights the impact of stochastic traffic network flow effects on fleet planning process and is employed to construct an enhanced revenue model by incorporating the expected revenue optimization model into fleet planning process. The objective of the model is to find a feasible allocation of aircraft fleet types to route legs using minimum fleet purchasing cost, thus ensuring that the expected fleet profit is maximized subject to several critical resource constraints. By using a linear approximation to the total network revenue function, the fleet planning model with enhanced revenue modeling is decomposed into the nonlinear aspects of expected revenue optimization and the linear aspects of determining fleet size and structure by optimal allocation of aircraft fleet types to route legs. To illustrate this methodology and its economic benefits, an example consisting of 6 chosen aircraft fleet types, 12 route legs, and 57 path‐specific origin‐destination markets is presented and compared with the results found using revenue prorated fleet planning formulation. The results show that the fleet size and structure of the methodology proposed in this paper gain 211.4% improvement in fleet profit over the use of the revenue prorated fleet planning approach. In addition, comparison with the deterministic model reveals that the fleet size and structure of this proposed methodology are more adaptable to the fluctuations of passenger demands. Copyright © 2016 John Wiley & Sons, Ltd.     

近年世界油运市场的发展与趋势

总结了近年世界石油海运市场的需求、供给、发到船量与运价的发展趋势,对中国油运船队的发展提出一些看法。