考虑异质性的经典随机后悔最小化模型改进研究

传统基于后悔理论的交通行为模型对异质性考虑不充分，对真实选择行为的解释存在不足.本文利用韦伯比率，考虑出行者对各方式属性变量感知的异质性，对经典随机后悔最小化模型进行改进，分别建立基于随机效用最大化，经典随机后悔最小化和改进经典随机后悔最小化的选择模型；以网约车选择行为为例进行实证研究，验证改进模型效果.结果表明：3种模型参数标定结果具有一致性，改进模型的拟合优度(0.271)和命中率(75.8%)相较于另外两个模型均较优；改进模型能更好地描述多维属性决策过程中的半补偿原则和折中效应，可以提高模型对真实选择行为的解释能力.     

Discussing the “positive utilities” of autonomous vehicles: will travellers really use their time productively?

ABSTRACT

Autonomous vehicles (AVs) are expected to reshape travel behaviour and demand in part by enabling productive uses of travel time—a primary component of the “positive utility of travel” concept—thus reducing subjective values of travel time savings (VOT). Many studies from industry and academia have assumed significant increases in travel time use and reductions in VOT for AVs. In this position paper, I argue that AVs’ VOT impacts may be more modest than anticipated and derive from a different source. Vehicle designs and operations may limit activity engagement during travel, with AV users feeling more like car passengers than train riders. Furthermore, shared AVs may attenuate travel time use benefits, and productivity gains could be limited to long-distance trips. Although AV riders will likely have greater activity participation during travel, many in-vehicle activities today may be more about coping with commuting burdens than productively using travel time. Instead, VOT reductions may be more likely to arise from a different “positive utility”—subjective well-being improvements through reduced stresses of driving or the ability to relax and mentally transition. Given high uncertainty, further empirical research on the experiential, time use, and VOT impacts of AVs is needed.     

功率变流器拓扑结构共模电压的比较和降低

所有由接地的电网系统供电并向可变输出系统供电的开关变流器拓扑结构,都会在负载装置上产生共模电压.系统地分析了用在交流传动装置上的各种变流器拓扑结构的共模电压,包括两点式电压源逆变器(VSI)、电流源逆变器(CSI)以及多点式逆变器.还分析了每种拓扑结构中使用的有源前端整流器.分析了共模电压的来源,并比较了由不同变流器拓扑结构产生的共模电压幅值.讨论了共模电压和降低共模电压技术的实际意义,并提供仿真和试验结果加以证明.     

一种分布式协同优化的认知无线电网络频谱检测算法

针对动态认知无线电网络中频谱检测性能与资源消耗之间的矛盾,提出一种分布式协同优化的频谱检测算法.设置双门限将认知用户分成可信组和非完全可信组.采用次梯度法对频谱检测效用函数进行分布式协同优化,动态调整能量检测阈值,提高动态变化网络环境中的非完全可信认知用户检测结果的准确性,并根据优化过程的收敛速率,从中选择参与协作的认知用户.最后融合中心通过加权融合获得频谱检测结果.仿真实验和分析表明算法在提高认知用户频谱检测准确性和检测速度的同时,降低了网络开销.     

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石太客运专线是我国铁路快速客运网的骨架之一，亦是铁路网“八纵八横”主通道的重要组成部分。本文通过对石太客运通道旅客进行大量问卷调查的基础上，根据通道的实际情况，引入了旅客交通方式选择行为的效用函数，对传统的Logit模型进行改进，构建了石太客运通道中客运专线和高速公路的竞争模型，对通道两种最主要交通方式的市场竞争能力进行分析。最后，以高速公路旅行速度和票价为主要扰动变量，分析高速公路服务水平变化，对石太客运专线竞争能力的影响。结论对提高石太客运专线运营管理水平，合理制定运输组织方案，具有重要的参考价值。     

出行时耗的规律及启示

出行时耗是指人们用于出行的时间.城市居民一天出行的平均时耗是否具有一定的稳定性,或者是否存在固定的出行时耗预算,多年来一直是城市交通领域工作者的研究热点之一.首先,在回顾国外相关研究的基础上,分析说明我国城市居民人均日出行时耗的规律性.通过近2年国内几个城市的调查数据,说明出行时耗稳定性在集计水平上是存在的.最后,综合分析了出行时耗稳定性的形成机理及出行时耗稳定性对于交通系统建模与分析的启示.     

以集液盒为主的实用新型专利的技术要点及应用分析

以集液盒为主的实用新型专利的主要是针对汽车底盘技术领域出现的燃油箱问题而开发的专利技术及实施方案。该专利以集液盒原理和使用改进以及带有集液盒的燃油箱的技术分析和方案设置,从而有效解决碳罐失效的问题。本文以集液盒为主的实用新型专利为研究重点,分析该专利的技术要点及在汽车底盘领域的具体应用。     

Things planners believe in,and things they deny

The paper examines the economic theory of consumer behavior from the Modern Psychoanalytic point of view with a metaphor of (transport) planning as a backdrop. It is claimed that the utility maximization principle of economic theory, no matter how broadly interpreted, does not envelop the motivation of human behavior and that the economic explanation of the aims of human behavior, which disregards the "dark side" of man, will result in narrowly conceived plans and policies.The application of economic theory, and other social sciences, to public policy has led to disjointedness of data collection, method of analysis, and planning and implementation. This, combined with a tautological behavioral theory, has made the current planning and public policy procedures self-verifying, and issues an invitation for a new theoretical approach which is comprehensive, does not ignore complexity and the large "error term", and appreciates the unity of data collection, method of investigation, and process of implementation.It is argued that unsatisfactory performance of the transport system, large errors inherent in data and models, the inability of extant transportation planning and policy to address key issues successfully, the environmental problem, and the value of the individual all call for new kinds of skills from the planners and policy makers.Freud's dualistic formulation of instinctual drives -- the life and death instincts -- is used as the new framework of explanation. This theory is seen to offer a convincing, more realistic and deeper understanding of the forces motivating human behavior, and one which is more in accordance with observable facts. If applied, the theory will lead to significantly different planning processes and to a profoundly different approach to public policy.     

建设城市地下综合管廊,转变城市发展方式

阐述建设地下综合管廊对推进新型城镇化、补齐城市基础设施短板,实现城市发展方式转变的重大意义;介绍世界发达国家、地区以及我国大陆建设地下综合管廊的情况;简述国务院推进地下综合管廊建设的重要决策部署。针对当前我国地下综合管廊的建设情况,提出以下建议。1)加强顶层设计,积极有序推进。2)完善相关配套政策,包括明确入廊要求、实行有偿使用、加大政府投入、完善融资支持等。3)具体措施:(1)借鉴国外先进经验,完善法规体系;(2)系统科学地编制好城市综合管廊规划;(3)建立统一管理、分工协作、衔接有序的综合管廊管理体制;(4)地下综合管廊兼顾人防应到位而不越位;(5)推广PPP模式,创新投融资机制。     

我国城市地下综合管廊工程建设中的若干问题

为进一步加强城市地下综合管廊工程管理,确保综合管廊有序、科学建设。针对近年来综合管廊工程建设中存在的问题,在解读国家相关政策要求的基础上,分析综合管廊系统规划、入廊管线、施工方法、安全保障、投资与收费等方面的问题,并提出相应的建议:1)要加强顶层设计、规划引领,精心编制规划,敬畏规划的严肃性,真正发挥规划的引领、指导、约束作用;2)发挥综合管廊工程建设的集约化作用,创造条件尽可能让多的管线在综合管廊内部敷设;3)创新施工方法,确保施工质量;4)建管并举,确保安全;5)认清综合管廊的社会公益地位,尊重管线单位的意见和诉求。