Not bored yet - Revisiting respondent fatigue in stated choice experiments

Stated choice surveys are used extensively in the study of choice behaviour across many different areas of research, notably in transport. One of their main characteristics in comparison with most types of revealed preference (RP) surveys is the ability to capture behaviour by the same respondent under varying choice scenarios. While this ability to capture multiple choices is generally seen as an advantage, there is a certain amount of unease about survey length. The precise definition about what constitutes a large number of choice tasks however varies across disciplines, and it is not uncommon to see surveys with up to twenty tasks per respondent in some areas. The argument against this practice has always been one of reducing respondent engagement, which could be interpreted as a result of fatigue or boredom, with frequent reference to the findings of Bradley and Daly (1994) who showed a significant drop in utility scale, i.e. an increase in error, as a respondent moved from one choice experiment to the next, an effect they related to respondent fatigue. While the work by Bradley and Daly has become a standard reference in this context, it should be recognised that not only was the fatigue part of the work based on a single dataset, but the state-of-the-art and the state-of-practice in stated choice survey design and implementation has moved on significantly since their study. In this paper, we review other literature and present a more comprehensive study investigating evidence of respondent fatigue across a larger number of different surveys. Using a comprehensive testing framework employing both Logit and mixed Logit structures, we provide strong evidence that the concerns about fatigue in the literature are possibly overstated, with no clear decreasing trend in scale across choice tasks in any of our studies. For the data sets tested, we find that accommodating any scale heterogeneity has little or no impact on substantive model results, that the role of constants generally decreases as the survey progresses, and that there is evidence of significant attribute level (as opposed to scale) heterogeneity across choice tasks.     

船舶避让行动浅析

从建立船舶智能避碰系统所需要的角度出发,对船舶避碰过程中的会遇态势、避让责任、避让时机和避让行动等问题进行了分析和归类。     

考虑不对称性的地铁旅客支付及受偿意愿研究

支付意愿与受偿意愿是交通评价及服务水平优化的关键输入参数,但现有关于地铁系统的研究及实证多未考虑两者间的不对称性. 针对这一问题,依托成都地铁旅客路径选择SP 数据,基于非集计模型,构建并标定了对称同质偏好、不对称同质偏好、对称异质偏好、不对称异质偏好等异构模型;分别从个体及总体水平求解,对比换乘走行时间、换乘等待时间、换乘次数和拥挤乘车时间的支付意愿与受偿意愿. 结果表明,受偿意愿与支付意愿的不对称性在总体水平大小及个体间异质性方面皆有体现,参数分布假设对不对称异质偏好模型支付意愿与受偿意愿求解结果影响明显.     

不同信息下的逐日路径选择行为实验与模型

为研究先进出行者信息系统(ATIS)对出行者逐日路径选择行为的影响,本文基于 Braess路网设计5组具有不同ATIS市场占有率(0、25%、50%、75%、100%)的行为实验.结果表明：3条路径的流量及新增路径保持选择的次数持续波动,随着ATIS市场占有率增大,路网平均行程时间趋于用户均衡,新增路径保持选择的次数呈现增长趋势,且被试对新增路径的选择性偏好增强,Braess悖论的效果也更明显.基于5组实验数据,分别建立普通Logit模型和基于面板数据的随机效应Logit模型刻画路径选择行为.结果表明：当ATIS市场占有率为0时,最佳模型为普通Logit模型;当ATIS市场占有率增大甚至达到100%时,最佳模型均为随机效应Logit模型;未配备ATIS的出行者的个体差异性比配备ATIS的小.     

广州地铁1号线的线路专业委外维修模式

随着广州地铁线网的快速发展,现有的维修模式不能满足地铁的超常规发展,探索新的维修模式成为地铁运营的一个重要课题.以广州地铁线路专业现有的维修模式为基础,从技术、经济、维修质量的控制、风险管理控制、生产组织、项目管理等方面进行委外维修模式的论述,阐明委外维修的目的和内容,并进行可行性分析.     

乌江中上游双尾与隧道尾结合的机动驳船型

本文通过对隧道尾涡尾及隧道尾与双尾结合尾型等三种船型的船模快速性试验结果分析，得出隧道与双尾结合船型是浅水充机动驳适宜的船型，其单位功率负载率和海军系数较现有优秀隧道尾船型分别提高２８．６１％和３４．３１％。     

全点阵显示屏工业应用文本显示管理系统

介绍全点阵显示屏文本显示管理系统构成原理，阐述系统的主要功能特点，并简要介绍该显示屏作为一种新的技术管理手段在工业生产流水线上的应用。     

Slow drift damping force acting on a horizontal cylinder

The hydrodynamic forces acting on a circular cylinder and a rectangular cylinder undergoing slow drift oscillation in regular waves were investigated experimentally and numerically. Forced oscillation tests with low frequency and large amplitude in regular waves and forced two-harmonic oscillation with combined low and high frequencies were carried out in the experimental study. In the numerical study a finite-difference method was used to simulate viscous flow around a two-dimensional oscillating cylinder. The results of experiments showed that a horizontal rectangular cylinder oscillating slowly in waves has much higher damping coefficients than one oscillating in two-harmonic mode, while the numerical study indicated that such differences in the damping coefficient arise partly from the different effects of one-direction harmonic flow and rotating flow on the vortex shedding caused by the slow drift oscillation.     

8K型机车监控装置双机备用系统

分析了8K型机车监控装置双主机和显示器的使用及存在的一些问题,并针对这些问题可能造成的隐患提出了解决的方案。指出了使用单片机智能化设计,以保证系统工作稳定可靠。同时给出了方案的整体试验结果和结论。