A nested recursive logit model for route choice analysis

We propose a route choice model that relaxes the independence from irrelevant alternatives property of the logit model by allowing scale parameters to be link specific. Similar to the recursive logit (RL) model proposed by Fosgerau et al. (2013), the choice of path is modeled as a sequence of link choices and the model does not require any sampling of choice sets. Furthermore, the model can be consistently estimated and efficiently used for prediction.A key challenge lies in the computation of the value functions, i.e. the expected maximum utility from any position in the network to a destination. The value functions are the solution to a system of non-linear equations. We propose an iterative method with dynamic accuracy that allows to efficiently solve these systems.We report estimation results and a cross-validation study for a real network. The results show that the NRL model yields sensible parameter estimates and the fit is significantly better than the RL model. Moreover, the NRL model outperforms the RL model in terms of prediction.     

Location privacy preferences: A survey-based analysis of consumer awareness,trade-off and decision-making

With the advent and rapid dissemination of location-sensing information technology, the issue of location information privacy is receiving growing attention. Perhaps of greatest concern is ensuring that potential users of mobile Information and Communications Technologies (e.g., Location-Based Services and Intelligent Transportation Systems) are comfortable with the levels of privacy protection afforded them, as well as with the benefits they will receive in return for providing private location information. This paper explores the concepts of privacy risks, benefits, willingness to trade, and compensation in relationship to mobile and locational technologies using a stated preference survey to ascertain areas of interest in determining the trade-offs that consumers will be willing to make in return for mobility enhancements. Analysis of the survey leads to findings that while respondents believe that sharing data in the mobile environment may pose privacy risks, they do not generally take steps necessary to address these risks; that privacy preferences are impacted by a range of factors, including both personal and contextual considerations (such as factors arising from their specific situation at the time of information seeking); and that willingness to trade private location data is dependent upon a number of factors related to context, personal characteristics, expected benefits and degree of trust in the collecting organization.     

扣件DI弹条非正常部位断裂原因分析及结构优化

通过对DI弹条非正常部位断裂的研究,发现扣件安装时弹条与铁垫板安装孔发生接触,致使弹条在中肢与尾部圆弧过渡区域产生应力集中,发生早期疲劳断裂。本文在研究弹条结构及安装方式的基础上,在弹条的中肢与尾部圆弧过渡区域引入"凹面"结构,对弹条进行结构优化,并通过扣压力和疲劳性能检测、实验室疲劳断裂检验、现场试铺检验等对带有优化"凹面"结构的DI弹条性能进行检测。结果表明:优化后的弹条扣压力和疲劳性能均合格,且能有效抑制因接触产生的非正常部位断裂,提高弹条性能。     

Collision course? The North Airfield Safety Study at Los Angeles International Airport (LAX)

The LAX North Airfield Safety Study was undertaken by an Academic Panel consisting of the present authors, and was based in large part on a simulation that was conducted at FutureFlight Central at NASA Ames Research Center. The primary aim of the study was “to estimate as specifically as possible the level of future safety associated with several geometrical configurations of the LAX North Airfield.” This paper describes the study, and how it combined information from human-in-the-loop simulations at NASA with historical data from LAX and other US airports about runway incursions and collisions. The analysis indicated that, even under its existing physical layout, LAX North would experience very low risk of runway collisions at traffic levels projected for 2020. That risk could be reduced by about half if the North Airfield runways were reconfigured, and some reconfigurations would also add appreciably to the operational efficiency of the airport. But because the “baseline” level of risk is so low, the Study concluded that “it would be difficult to construct a compelling case on safety grounds alone for reconfiguring the North Airfield.”     

公路项目建设期利息计算方法进一步研究

对建设期利息计算过程中容易混淆的几个概念进行辨析，用数学方法证明了在项目建设计划、贷款流入的特点、贷款利率确定的条件下，项目建设期贷款利息为项目各年贷款投入比例的线性函数。     

浅析构造物台背处理技术

通过对桥头跳车现象的产生机理及其危害的分析,结合实际工作经验,提出防治措施,并对此防治措施展开探讨。     

公路边坡植物防护机理及应用技术的初步研究

随着我国经济建设的蓬勃发展,基础设施建设得到迅猛的发展。与此同时,基础设施建设与环境保护的矛盾也日益突出。为了实现高速公路的生态防护、保持生态平衡、减少水土流失、稳固路基、美化环境、减轻视觉疲劳等目标,要结合工程实际情况选择边坡的植被护坡方法。     

桥头跳车的病害原因及防治措施

较详细的分析了桥头跳车病害产生的的原因,并提出了相应的防治措施。     

沈阳地铁一号线工程风险分析

针对沈阳地铁一号线工程决策、设计、施工、运营阶段的风险因素进行分析，指出项目各阶段的管理风险、技术风险、环境风险等风险项目，重点分析了几种典型施工方法相关的风险因素，并提出了风险规避和预防的措施以及应急预案。     

土工格网加筋台背填土试验研究

路桥过渡段桥头跳车是高等级公路建设中较难处理的常见问题,往往给高速公路快速、平稳行车带来不利的影响。结合衡枣高速公路桥梁工程实例,介绍了采用土工格网进行桥台台背填土处理的方案,通过现场试验,分析土工格网处理桥头跳车的现场试验方法、数据分析及实际效果,为解决高速公路桥头跳车危害积累经验。