A distributed VNS algorithm for optimizing dial-a-ride problems in large-scale scenarios

These days, transportation and logistic problems in large cities are demanding smarter transportation services that provide flexibility and adaptability. A possible solution to this arising problem is to compute the best routes for each new scenario. In this problem, known in the literature as the dial-a-ride problem, a number of passengers are transported between pickup and delivery locations trying to minimize the routing costs while respecting a set of prespecified constraints. This problem has been solved in the literature with several approaches from small to medium sized problems. However, few efforts have dealt with large scale problems very common in massive scenarios (big cities or highly-populated regions). In this study, a new distributed algorithm based on the partition of the requests space and the combination of the routes is presented and tested on a set of 24 different scenarios of a large-scale problem (up to 16,000 requests or 32,000 locations) in the city of San Francisco. The results show that, not only the distributed algorithm is able to solve large problem instances that the corresponding sequential algorithm is unable to solve in a reasonable time, but also to have an average improvement of 9% in the smaller problems. The results have been validated by means of statistical procedures proving that the distributed algorithm can be an effective way to solve high dimensional dial-a-ride problems.     

Quantifying the environmental impacts of increasing high occupancy vehicle lanes in the United States

To what extent will increasing High Occupancy Vehicle (HOV) lane-kilometer incentivize carpooling and reduce emissions of air pollutants and greenhouse gases? To answer these questions, we develop a multiple regression model relating HOV lanes and other socioeconomic factors to carpooling propensity in all 50 U.S. states and the District of Columbia, then calculate the extent to which increasing HOV lane-kilometers would lead to reductions in carbon dioxide equivalent (CO₂e) and major air pollutants across the U.S., by state. Increasing HOV lane extent has the greatest potential to reduce annual CO₂e in the District of Columbia, followed by Hawaii and New York. The smallest potential is found in states with the lowest population density, led by North Dakota. We then explore the extent to which recommendations made at one level of data aggregation (that of individual states) may be valid for another level, such as individual counties. The only state with sufficient data available to disaggregate the model to the county level is California, where we found a lower potential for state-wide CO₂e emission reductions under the county-level model as compared to the state-level model (0.69% as compared to 1.08%, under the same hypothetical scenario), albeit with significant differences in emission reduction potential between counties with higher vs. lower population densities. This analysis demonstrates the potential to generate generalizable insight into the magnitude of vehicle emission reductions that might be achieved through expanding HOV lanes, and highlights the importance of data disaggregation in identifying the optimal locations for potential reductions.     

构建行业继续教育体系积极推进"人才强交"战略

坚持科学的人才观,牢固树立人才资源是第一资源,加强加快专业技术人员等交通从业人员继续教育和职业培训改革与发展,推进继续教育体系构建和培训模式创新,对于实施"科教兴交、人才强交"战略,实现交通新的跨越式发展具有重要的意义.     

太原铁路局危险货物运输安全专项整治对策

阐述太原铁路局危险货物运输现状,分析当前危险货物运输安全管理中存在的主要问题,提出加强危险货物运输安全的措施：全部实现源头＂机控＂把关;危险货物运输清理工作应全部到位;全面推进安全现状综合分析和安全评价工作;提升危险货物运输风险控制管理水平;提高应急救援的装备和应对能力;完善危险货物运输培训覆盖面,提高培训水平。     

关于钦州港站路港联合扩大运量的思考

为适应广西钦州港的建设和发展,分析钦州港站铁路运输现状,通过扩能改造增加运能,挖潜提效抢占运输市场,联劳协作促进货物周转,实现路港联合提高货运量。提出路港联合共谋发展,优化铁路运输组织,建设现代物流体系,及时掌握货运市场信息,积极协调港口、客户、总代理与铁路之间的各种关系,扩大铁路港站运量等措施。     

高速铁路发展对环境的影响分析

加快建设资源节约型,环境友好型社会迫在眉睫,其中构建有利于环境保护的交通运输体系是其关键之一.而发展高速铁路运输是构建可持续发展交通体系的核心.相对其他运输方式,铁路运输能源消耗低,污染排放少,综合性价比高,适合我国能源利用的要求,符合节能环保的要求.近几年,我国开展高速铁路建设,高速铁路相对普通铁路能源利用率更高,性价比更高,对环境的影响更小。     

我国铁路开行集装箱中转接续班列技术可行性探讨

分析我国铁路集装箱运输现状,利用图示说明我国开行铁路集装箱中转接续班列的思路,从集装箱中转接续班列的开行条件、班列编成辆数、集装箱在办理站的中转停留时间等方面对开行集装箱中转接续班列的技术可行性进行分析,并举例阐述了集装箱中转接续班列的始发终到时间制定,最后简要说明集装箱中转接续班列的运输组织方法。     

地方铁路保价运输研究及拓展

在分析河南汤台铁路有限公司保价运输现状及存在主要问题的基础上,提出了提高理赔服务质量、构建保价大客户营销体系、完善保价运输激励机制、加大安全基础设施投入、做好保价宣传等地方铁路拓展保价运输的建议。     

关于完善保价运输理赔机制的思考

从保价运输的起源分析货损理赔是保价运输的核心价值之一,指出铁路保价运输存在的责任认定及损失鉴定难、及时和高效的理赔服务及管理机制尚待落实、承保与理赔脱节等问题,以及保价运输应遵循的重约守信、实事求是、快速与高效的原则,提出加强理赔服务管理、完善理赔考核与监督机制、加强承保和理赔的协作、引入公估人制度等完善保价运输理赔机制的措施。     

基于现代物流理念的铁路货运营销策略研究

随着现代物流理念和技术在生产制造业的广泛应用和不断深化,其所带来的巨大潜在利润被更多的企业所重视。更加注重客户导向的营销策略使定制化的物流服务能力成为吸引顾客的重要变量,现代物流已经成为开展现代营销的一种必备手段。铁路提供的运输产品和满足消费需求的过程,与物流有着极其紧密的联系。在介绍国外铁路货运营销发展概况和经验的基础上,对我国铁路货运营销发展现状及市场变化进行分析,提出要应用现代物流的理念,通过开展第三方物流服务实现价值增值、依托信息技术突出核心竞争力、完善大客户管理体系、开展联运等方式提高铁路的市场竞争能力。