Neighborhood services,trip purpose,and tour-based travel

Communities are increasingly looking to land use planning strategies to reduce drive-alone travel. Many planning efforts aim to develop neighborhoods with higher levels of accessibility that will allow residents to shop closer to home and drive fewer miles. To better understand how accessible land use patterns relate to household travel behavior, this paper is divided into three sections. The first section describes the typical range of services available in areas with high neighborhood accessibility. It explains how trip-based travel analysis is limited because it does not consider the linked (chained) nature of most travel. The second section describes a framework that provides a more behavioral understanding of household travel. This framework highlights travel tours, the sequence of trips that begin and end at home, as the basic unit of analysis. The paper offers a typology of travel tours to account for different travel purposes; by doing so, this typology helps understand tours relative to the range of services typically offered in accessible neighborhoods. The final section empirically analyzes relationships between tour type and neighborhood access using detailed travel data from the Central Puget Sound region (Seattle, Washington). Households living in areas with higher levels of neighborhood access are found to complete more tours and make fewer stops per tour. They make more simple tours (out and back) for work and maintenance (personal, appointment, and shopping) trip purposes but there is no difference in the frequency of other types of tours. While they travel shorter distances for maintenance-type errands, a large portion of their maintenance travel is still pursued outside the neighborhood. These findings suggest that while higher levels of neighborhood access influences travel tours, it does not spur households to complete the bulk of their errands close to home.     

新型纤维增强混凝土梁的抗弯冲击特性

为了研究纤维增强混凝土梁的抗弯冲击特性．利用自制的自由落锤抗弯冲击试验装置，测定了不同体积掺率下细直径的腈纶纤维、聚酯纤维、玻璃纤维，粗直径的聚丙烯纤维和哑铃形钢纤维增强混凝土梁的抗弯冲击力学性能。试验表明：纤维增强混凝土梁的冲击次数与纤维品种和体积掺率有关；当细直径纤维的体积掺率为0．07％～O．27％时，纤维增强混凝土梁的初裂、破坏冲击次数分别为素混凝土的1．1～4．5倍和1．1～4．4倍；当粗直径纤维的体积掺率为O．5％～1．4％时，纤维增强混凝土梁的初裂、破坏冲击次数分别为素混凝土梁的2．4～4．6倍和5．2～31．0倍。细纤维增强混凝土梁的初裂冲击性能优于粗纤维增强混凝土梁．粗纤维增强混凝土梁的破坏冲击性能和冲击延性明显优于细纤维增强混凝土梁。     

UD63型尼桑汽车起动和充电系控制电路及故障排除

系统地介绍UD63型尼桑汽车起动系和充电系控制电路的原理及故障分析,并给出检修实例。有利于准确、快速地排除该类车型的故障。     

An Exploration of the Relationship between Timing and Duration of Maintenance Activities

The timing and duration of an activity episode are two important temporal aspects of activity-travel behavior. Understanding the causal relationship between these two variables would be useful in the development of activity-based travel demand modeling systems. This paper investigates the relationship between these two variables by considering two different causal structures – one structure in which time-of-day choice is determined first and influences duration and a second structure in which activity duration is determined first and affects time-of-day choice. These two structures are estimated within a discrete-continuous simultaneous equations framework employing a full-information maximum likelihood methodology that allows error covariance. The estimation is performed separately for commuter and non-commuter samples drawn from a 1996 household travel survey data set from the Tampa Bay area in Florida. The results of the model estimation effort show that the causal structure in which activity duration precedes or affects activity timing (time of day choice) performs better for the non-commuter sample. For the commuter sample, the findings were less conclusive with both causal structures offering equally good statistical measures of fit. In addition, for the commuter sample, all error correlations were found to be zero. These two findings suggest that time of day choice and activity episode duration are only loosely related for the commuter sample, possibly due to the relatively non-discretionary and inflexible work activity and travel.     

基于数据挖掘的城市机动车停车调查分析研究

进行城市机动车停车场规划前需要开展停车场调查,以得到停车场的基本特征参数、机动车进出记录和停车者的停车行为等信息。通过数据挖掘中的一些方法可以在数据库中挖掘出有用的信息。根据机动车进出停车场的记录计算一系列的停车指标,并借助多元统计分析中典型相关分析的方法,分析停车指标与停车场基本特征参数之间的关系。然后利用关联规则挖掘停车问询调查数据中的潜在信息,分析停车者的行为特征,以掌握更多的停车信息。     

跟驰过程中驾驶员认知结构模型的建立

在道路交通4要素中(人、车、路、环境),人以其主动性和智慧性起着支配作用,是其中的主体要素。基于认知心理学的有关知识,论文采用因子分析法对五轮仪实验系统观测到的车辆跟驰数据进行分析,确定了对车辆跟驰信息提取过程有独立作用的4个因素,相应地将驾驶员认知过程划分为4个阶段,建立了车辆跟驰过程的驾驶员认知结构模型。为驾驶行为研究和车辆跟驰模型的建立提供了理论基础。     

探索新能源汽车充电设施的电气设计

现如今,新能源电动汽车充电装置电气设计,得要顺应现代化实际需求与发展趋势。在后期发展阶段之中,新能源汽车会引领着整个汽车行业的发展,当然也可以凸显出节能减排、绿色出行的优势。因此在新能源项目发展阶段之中,针对新能源汽车充电设施实施电气设计至关重要。鉴于此,本文主要分析新能源汽车充电设施的电气设计。     

基于分子动力学的车流运行动态特性及其模型

车辆跟驰行为受前导车和道路环境等的影响,将车辆抽象成相互作用的分子,基于分子动力学构建相互作用势函数,建立基于相互作用势函数的分子跟驰模型.采集试验路段不同点位的交通流样本,从视频中获得所需数据,并对加速度波动特性进行分析.将车辆运行状态分为常态行驶,起动加速和减速停车3种,根据实测交通数据对3种车辆运行状态进行模型参数标定,同时对分子跟驰模型进行稳定性分析验证,结果表明,相对于经典GM模型,分子跟驰模型稳定性更好,对实际交通状态拟合程度更高.