An analysis of weekly out-of-home discretionary activity participation and time-use behavior

Activity-travel behavior research has hitherto focused on the modeling and understanding of daily time use and activity patterns and resulting travel demand. In this particular paper, an analysis and modeling of weekly activity-travel behavior is presented using a unique multi-week activity-travel behavior data set collected in and around Zurich, Switzerland. The paper focuses on six categories of discretionary activity participation to understand the determinants of, and the inter-personal and intra-personal variability in, weekly activity engagement at a detailed level. A panel version of the Mixed Multiple Discrete Continuous Extreme Value model (MMDCEV) that explicitly accounts for the panel (or repeated-observations) nature of the multi-week activity-travel behavior data set is developed and estimated on the data set. The model also controls for individual-level unobserved factors that lead to correlations in activity engagement preferences across different activity types. To our knowledge, this is the first formulation and application of a panel MMDCEV structure in the econometric literature. The analysis suggests the high prevalence of intra-personal variability in discretionary activity engagement over a multi-week period along with inter-personal variability that is typically considered in activity-travel modeling. In addition, the panel MMDCEV model helped identify the observed socio-economic factors and unobserved individual specific factors that contribute to variability in multi-week discretionary activity participation.

车载作用下土基永久变形机理及影响因素分析

论述了土基永久变形的发展机理及其危害性,并从内、外因两个方面分析了影响土基永久变形的重要因素,为利用室内重复荷载三轴试验研究路基土的永久变形特性提供了参考依据。     

加入WTO对我国航运市场影响的研究

在研究我国目前航运7市场现状的基础上,分析国际航运的可控制影响因素,提出加入WTO后将对我国航运市场产生的影响,并制定若干对策。     

三体船耐波性预报

应用三维势流理论,计算了三体船在不同航速下垂荡、纵摇、横摇运动频率响应函数。预报了三体船在不规则波中各种海况下航行时的运动和加速度有义值,同时分析了三体船在西北太平洋海区一定海况下的运动特征和规律,最终根据舰船耐波性衡准要求,确定了三体船适合航行的海况与航速,为三体船耐波性方面得出了有价值的参考。     

沥青混凝土路面平整度探析

如何保证沥青混凝土路面的平整度,提高路面工程的质量,是高等级公路建设中的难点、重点。分析影响路面平整度的因素,从基础处理、材料控制、施工工艺等方面提出改善路面平整度的措施。     

Numerical Calculation of Marine Propeller Hydrodynamic Characteristics in Unsteady Flow by Boundary Element Method

In this paper, a low-order potential based on surface panel method is used for the analysis of marine propellers in unsteady flow.A linear propeller wake model is employed and its geometry is assumed to be independent of the time.The calculation in time domain is carried out from a moment when the rotation of the propeller becomes steady instead of from the moment when the rotation strats from stationary condition.At every time step a linear algebraic equation established on a key blade is solved numerically combined with the Kutta pressure conditon.The calculated results by developed code indicate good convergency and effrctiveness of present algotithm for conventional propellers and highly skewed propellers.     

大型机场轨道交通发展影响因素及衔接模式——以美国东海岸机场为例

中国大多数机场在规划之初并未将轨道交通纳入机场集疏运体系,同时城市群区域多机场对多城市的状况也为机场间的陆侧交通衔接带来巨大挑战。以美国东海岸7个典型机场为研究对象,分析机场轨道交通发展因素及衔接模式。基于案例机场陆侧轨道交通客运量和分担率变化情况,总结轨道交通需求增长趋势,剖析机场轨道交通需求增长影响因素,包括机场客运吞吐量增加、非商务旅客出行比例增加、航空旅客年龄及收入降低,以及携带行李数量增加。最后,总结机场与陆侧轨道交通衔接的3种主要模式及其适用条件。     

缓解城市交通拥堵的CO2减排效益评估方法研究

城市交通拥堵是导致城市交通碳排放快速增长的重要原因. 分析影响城市交通碳排放的关键因素,收集现有碳排放因子,开展车辆排放测试,建立不同道路类型和服务水平的城市交通碳排放因子数据库. 对ASIF 方法进行改进,基于城市交通拥堵的分类方法,提出中观尺度的城市交通缓堵减排效益评估方法和模型. 以成都市为例,开展城市调研、数据采集与分析、模型运算,评估成都全年城市交通的碳排放总量,其中,交通拥堵的碳排放占48.2%. 设置4种正向减排发展情景和3种反向恶化发展情景,分析不同情景下的碳排放效果.     

中国交通运输业能源回弹效应研究

为厘清中国交通运输业能源消耗量攀升的原因,本文应用中国交通运输业1991-2014年的数据,基于超越对数生产函数估计出各投入要素的产出弹性和技术进步对产出增长的贡献率,进而测算出中国交通运输业的能源回弹效应.研究结果表明,样本期内中国交通运输业存在较为严重的要素错配与效率损失;中国交通运输业仅有少数年份出现了回弹效应,且有"回火"情形出现;多数年份里中国交通运输业由于能源效率无改善或技术无进步而未形成能源回弹效应,中国交通运输业能源消耗量攀升的主要原因在于行业"高增长、高能耗"的粗放式发展方式.     

隧道洞口交通安全影响因素分析与对策

高速公路隧道洞口变通事故原因具有多样性、复杂性的特点。通过对高速公路上隧道洞口变通事故特征的调查．以人、车、路和周围环境体系分析隧道洞口交通安全的影响因素,有利于提出隧道洞口变通安全性的合理对策。