You (expect to) get what you pay for: A system approach to delay, fare, and complaints

In this paper, an analytical framework integrating delay, fare, and complaints with passenger air travel has been laid out. Examining aggregate monthly data for US domestic air travel, we have identified causal relationships among fare, complaints, and levels of delay. An analytical framework is proposed that formalizes these relationships in an integrated manner. This integrated framework is then estimated in a set of simultaneous equations by using 118 months of data from January 1997 to October 2006. Results show that complaints are influenced by levels of delays. However, complaints are positively influenced by average yield. These findings lead us to support the central hypothesis that complaints are responsive to levels of delays, but they tend to vary according to fare. That is, air travelers are less likely to complain in return for lower fares, even when faced with the same or even higher levels of delays. These findings have important policy implications, including the passengers’ bill of rights and regulator’s choice between market and operational performances.     

2020全球限硫令对海员权益的影响

2020全球限硫令的推出,对各方均造成了极大的影响。为确保海员权益不受损害,文章结合国内外资料以及对部分海员的访谈,在国内首次系统分析了2020全球限硫令的实施对海员在人身安全、职业健康、工作休息、工资报酬、责任追究等五方面影响;并首次从船东和主管机关的角度分别提出了履行2020全球限硫令时保护海员权益的建议,即船东要加强培训、确保船舶配员、关注海员职业健康和工资报酬,船旗国和港口国主管机关要加强海员权益保护检查、确保提供合格燃料油以及给予海员足够的宽容和理解等。     

深圳港区跨海货运通道方案比选研究

深圳市妈湾跨海通道蛇口—赤湾连接线工程是深圳港区跨海货运通道的一部分,建设条件复杂,为此开展多线位、多工法方案综合比选,以确定兼顾各方需求的优化方案。对工程的功能定位、港区货运需求、沿线用地情况及规划等因素进行了详细分析,对跨海货运快速路通道从选线、工法、设计方案逐层递进,进行多方案比选。综合考虑了地下空间充分利用、减少对港区用地占用,降低施工对疏港交通影响等因素,确定了项目的选线方案以及双管单层15 m盾构的工法和设计方案。成果为深圳市等港区货运通道的选线及设计方案提供借鉴。     

Sensitivity-based uncertainty analysis of a combined travel demand model

Travel demand forecasting is subject to great uncertainties. A systematic uncertainty analysis can provide insights into the level of confidence on the model outputs, and also identify critical sources of uncertainty for enhancing the robustness of the travel demand model. In this paper, we develop a systematic framework for quantitative uncertainty analysis of a combined travel demand model (CTDM) using the analytical sensitivity-based method. The CTDM overcomes limitations of the sequential four-step procedure since it is based on a single unifying rationale. The analytical sensitivity-based method requires less computational effort than the sampling-based method. Meanwhile, the uncertainties stemming from inputs and parameters can be treated separately so that the individual and collective effects of uncertainty on the outputs can be clearly assessed and quantified. Numerical examples are finally used to demonstrate the proposed sensitivity-based uncertainty analysis method for the CTDM.     

整体表面淬火强化的铸钢摩擦楔

对货车转向架减振部件铸钢摩擦楔的使用寿命和耐磨性进行了研究,建议采用整体表面淬火工艺提高寿命。     

On the degradation of performance for traffic networks with oblivious users

We consider the problem of characterizing user equilibria and optimal solutions for routing in a given network. We extend the known models by considering users oblivious to congestion in the following sense: While in the typical user equilibrium setting the users follow a strategy that minimizes their individual cost by taking into account the (dynamic) congestion due to the current routing pattern, an oblivious user ignores congestion altogether; instead, he or she decides his routing on the basis of cheapest routes on a network without any flow whatsoever. These cheapest routes can be, for example, the shortest paths in the network without any flow. This model tries to capture the fact that a certain percentage of travelers base their route simply on the distances they observe on a map, without thinking (or knowing, or caring) about the delays experienced on this route due to their fellow travelers. In this work we study the effect of such users using as the measure of network performance its price of anarchy, i.e., the ratio of the total latency experienced by the users (oblivious or not) at equilibrium over the social optimum.     

铁路建设物资汽车运输单价探讨

铁路建设工程投资主要由工料机费用、运输费及其他相关费用组成。运输方面的费用通常占静态投资的3％-10％，而采用汽车运输物资的费用占到总运输费用的65％～90％。为此，合理确定建设项目汽车运输物资的单价就显得格外重要。此文结合有关计算汽车运输单价的规定和执行情况及存在的主要问题，分析影响汽车运输单价的因素。并采用既有概预算编制办法的有关规定测算汽车运输单价，与采用自卸汽车运输和路基运输定额测算的汽车运输单价进行比较分析，研究其影响因素和运价率的一般规律。提出合理确定汽车运输单价的建议。     

铁路货车下作用车钩防跳插销故障分析

分析了下作用车钩防跳插销故障的原因及危害,并提出了防范措施。     

大型机场地面集疏运需求预测方法研究

机场地面集疏运系统是机场发展的重要支撑，交通需求预测是进行机场集疏运交通规划的前提。笔者以四阶段预测的基本原理为基础，结合机场集疏运需求特点，对预测的整体思路、方法、步骤和内容等进行详细分析，优化调整出行分布、方式划分预测模型，并以南京禄口国际机场为实例进行了预测。研究成果对国内同类大型机场的集疏运需求预测具有借鉴和参考价值。