Integrated models of land use and transportation for the autonomous vehicle revolution

ABSTRACT

The advent of the autonomous vehicle (AV) will affect not only the transportation system, but also future patterns of land development. Integrated land use and transportation models will be critical tools in assessing the path forward with this technology. Key questions with respect to land use impacts of AVs arise from potential changes in sensitivity to travel and reduced demand for parking. It is an open question whether AVs will induce urban sprawl, or whether spatial economies of agglomeration will mitigate any reductions in travel time sensitivity. The deployment of shared fleets of AVs would likely reduce parking demand, producing yet to be explored impacts on property development within existing urban footprints. We perform a critical assessment of currently operational models and their ability to represent the adoption of AVs. We identify the representation of time in such models as a vital component requiring additional development to model this new technology. Existing model applications have focused on the discrete addition of new infrastructure or policy at a fixed point in time, whereas AV adoption will occur incrementally through time. Stated adaptation surveys are recommended as tools to quantify preferences and develop relevant model inputs. It is argued that existing models that assume comparatively static equilibrium have been convenient in the past, but are insufficient to model technology adoption. In contrast, dynamic model frameworks lack sufficient structure to maintain reasonability under large perturbations from base conditions. The ongoing advancement of computing has allowed models to move away from being mechanistic aggregate tools, towards behaviourally rich depictions of individual persons and firms. However, much work remains to move from projections of existing conditions into the future, to the evolution of the spatial economy as it evolves through time in response to new technologies and exogenous stresses. Principles from complex and evolutionary systems theory will be important in the development of models with the capacity to consider such dynamics.     

福州东(樟林)车辆段工艺设计实践与创新

随着铁路建设的发展,福建省境内货车保有量大幅度增长,货车检修任务量增加迅速。樟林编组站位于福州枢纽,具备良好的扣车条件,在此新建1处货车车辆段将解决整个福建省货车的定期检修工作,而且能保障列车的运行安全,节约运输成本以及货车周转时间。福州东车辆段出入段线下穿既有温福铁路,有利于行车组织、运营安全。总图因地制宜全创新提出存车线(预检预修)与修车库贯通布置方案。充分梳理预检预修与架落车工艺,提出独立设置预检预修设施。论述抛丸除锈设备独立设置、转向架单臂悬挂检修流水线等修车库与联合车库创新设计,福州东(樟林)车辆段设计实现了创新理念和工程实际的协调统一。     

Online channel strategies under different offline channel power structures for the Belt and Road of China

ABSTRACT

This paper explores the online channel strategies adopted by Chinese manufacturers with regard to the Belt and Road. It also investigates the effect of offline channel power structures and maritime transportation costs on online channel mode selection and pricing strategies. The offline channel power structures are classified into three types, namely, Chinese manufacturer Stackelberg (MS) structure, vertical Nash (VN) structure, and foreign retailer Stackelberg (RS) structure. Furthermore, a game model is developed among the Chinese manufacturer, foreign retailer, and cross-border e-tailer to investigate the interactions among offline channel power structures, maritime transportation costs, and Chinese manufacturers’ online channel mode selection. The results show that Chinese manufacturers’ preferences for the online agency selling mode increases correspondingly with the decrease in their market position and bargaining power. Moreover, foreign retailers can obtain higher profits in the online agency selling mode under the VN structure. However, the level of profit for foreign retailers depends on the intensity of their competition with cross-border e-tailers under the MS and RS structures. Finally, consumers in countries along the Belt and Road can obtain a higher surplus in the online agency selling mode under all of the structures.     

狗左右心室和肺循环功能的同步测定与评价

本文介绍了狗左、右心室和肺循环功能的同步测定方法,并同时观察了左、右心室收缩、舒张性能、泵功能和肺循环功能的多项指标。在实验条件下,动物的生理状况在3小时内基本稳定。     

浅谈青藏线转辙设备的养护与维修

本文根据CTS2轨枕式转辙机本身的特点以及青藏铁路的管理模式，从养护、维修的角度，简要说明了CTS2轨枕式转辙机需要的养护工作量、故障处理方法、维修特点及在施工中要注意的问题。     

船舶除锈机器人驱动系统设计

介绍了应用在船舶除锈的磁吸附爬壁机器人本体驱动系统的设计,着重阐述了系统的驱动原理和驱动电路。系统以89c51单片机为核心,通过键盘以及通信接口可以方便的控制步进电机带动机器人本体运动,充分发挥了单片机的优势。实验表明,系统电路设计合理,简单实用。     

填石路堤的摊铺工艺研究

填石路堤的施工工艺是路堤工程质量控制的一个重要方面,施工工艺控制的好坏直接影响着施工质量。其中,摊铺工艺尤为重要。     

自激多谐继电器稳定可靠性的提高措施

针对闪光器普遍存在闪频不稳的现象，分类叙述影响自激多谐继电器闪频的因素，并提出提高其稳定可靠性的具体措施。     

优化运输结构加快铁路发展

交通运输业的发展受资源环境约束,各种运输方式在资源消耗和环境保护等方面存在较大差异,对资源和环境的影响也不同。我国各种运输方式发展的关键是在资源环境约束条件下协调发展。深入贯彻落实科学发展观,加强统筹协调和宏观调控,推进交通运输结构优化,加快铁路发展,提高铁路运输能力,促进节能减排、资源节约型和环境友好型社会建设。     

70 m跨二铰型上承式桁架混凝土拱桥的施工技术

介绍70 m双铰型上承式桁架拱桥的施工和在施工阶段监测监控的内容及方法,可供类似工程建设参考。