输卵管结扎与盆腔静脉瘀血

为探讨输卵管结扎术与盆腔静脉瘀血发生的关系，对250例输卵管结扎术后行复通术（观察组）及100例仅行输卵管结扎术的妇女（对照组）分别进行了术中盆腔情况观察。发现两组之间的盆腔静脉曲张发生率有显著的差异；观察组中各种手术结扎方式与结扎部位不同，其盆腔静脉曲张发生率无明显差异。表明输卵管结扎手术所造成的损伤或局部病变是发生盆腔静脉瘀血众多因素中主要因素之一，而观察组中出现盆腔静脉曲张的患者并无临床表现，证实存在亚临床无症状的盆腔静脉曲张。     

定制公交浅析

介绍了定制公交推出的社会背景,阐述了定制公交的含义、运作机制、特点及优势,论述了开通定制公交的成效。     

基于道路拥堵信息的公交出行规划系统

针对当前道路拥堵增多的情况,建立了一个基于道路拥堵信息的公交出行规划系统,以引导公众避开拥堵道路。分析道路拥堵状况的指标体系,分别选取路段和交叉口的通行参数指标,并给出一种红绿灯等待灯次的简便算法,提出公交出行规划方案的拥堵指数算法。以嘉兴市为例,采用SQL＋IIS＋ASP＋Android技术构建了C/S架构的基于道路拥堵信息的动态公交出行规划系统。该系统推荐的出行方案能引导用户避开拥堵道路,提高出行效率,减少出行时间,为公众出行提供了更全面的公交出行信息和更便利的信息获取途径。     

考虑碳成本的城市交通拥挤定价模型研究

从研究国内外交通二氧化碳排放及收费和国内外拥挤定价现状入手,分析了城市交通二氧化碳排放的特征,在总结国内外碳税征收标准的基础上,建立了城市交通碳排放收费模型;将碳排放费用视为广义出行费用的一部分,进而建立了考虑碳排放成本的拥挤定价双层规划模型,选取实际案例验证其合理性与可行性,也为我国城市交通拥挤定价提出合理的建议.     

考虑停车换乘及停车收费的拥堵收费公平性影响研究

通过对联合停车的拥堵收费分析,为确定不同出行方式中单人城市道路资源占用量和比例以及相同出行方式的人群占总出行量的比例,作者根据十种方式的人口比例和实际占有的道路资源份额绘制了洛伦兹曲线,并用标定曲线的数学模型来计算基尼系数,评价了公平程度。此外,论文比较此政策实施前后洛伦兹曲线、基尼系数。最后,用数据进行了计算和分析,说明了该方法的有效性,能够对拥挤收费的公平性进行有效的分析。该研究为拥挤收费的实施提供了相关借鉴。     

Automated vehicles: exploring possible consequences of government (non)intervention for congestion and accessibility

ABSTRACT

Academic research on automated vehicles (AVs) has to date been dominated by the fields of engineering and computer science. Questions of how this potentially transformative technology should be governed remain under-researched and tend to concentrate on governing the technology’s early development. We respond in this paper by exploring the possible longer-term effect of government (lack of) intervention.

The paper tests the hypothesis that a “laissez-faire” governance approach is likely to produce less desirable outcomes in a scenario of mass uptake of AVs than would a well-planned set of government interventions. This is done using two prominent themes in transport policy – traffic flow and accessibility – in a scenario of high market penetration of Level-5 automated vehicles in capitalist market economies. The evidence used is drawn from a literature review and from the findings of a set of workshops with stakeholders.

We suggest that a laissez-faire approach will lead to an increase in traffic volume as a result of a growing population of “drivers” and a probable increase in kilometres driven per passenger. At the same time, the hoped-for increases in network efficiency commonly claimed are not guaranteed to come about without appropriate government intervention. The likely consequence is an increase in congestion. And, with respect to accessibility, it is likely that the benefits of AVs will be enjoyed by wealthier individuals and that the wider impacts of AV use (including sprawl) may lead to a deterioration in accessibility for those who depend on walking, cycling or collective transport.

We consider the range of possible government intervention in five categories: Planning/land-use; Regulation/policy; Infrastructure/technology; Service provision; and Economic instruments. For each category, we set out a series of interventions that might be used by governments (at city, region or state level) to manage congestion or protect accessibility in the AV scenario described. Many of these (e.g. road pricing) are already part of the policy mix but some (e.g. ban empty running of AVs) would be new. We find that all interventions applicable to the management of traffic flow would also be expected to contribute to the management of accessibility; we define a small number of additional interventions aimed at protecting the accessibility of priority groups.

Our general finding is that the adoption of a package of these interventions could be expected to lead to better performance against generic traffic-flow and accessibility objectives than would a laissez-faire approach, though questions of extent of application remain.

In our conclusions, we contrast laissez-faire with both anticipatory governance and “precautionary” governance and acknowledge the political difficulty associated with acting in the context of uncertainty. We point out that AVs do not represent the first emerging technology to offer both opportunities and risks and challenge governments at all levels to acknowledge the extent of their potential influence and, in particular, to examine methodically the options available to them and the potential consequences of pursuing them.     

城市轨道交通峰前折扣定价方案编制模型

构建面向高峰拥挤缓解的峰前折扣定价方案编制模型，为定价方案编制提供决策方法. 基于票价变动对高峰客流的影响分析，考虑运营企业可承担的收益损失，建立以运力运量匹配度最大化为目标的峰前折扣定价方案编制模型，科学确定折扣车站、折扣比例及折扣时段. 对北京地铁八通线进行实证研究，结果表明：相比实际方案，优化方案中折扣截止时间较晚，认为限制当前政策效果的关键在于折扣截止时间设置不合理；在不增加收益损失的前提下，可通过定价方案优化提高客流拥挤疏解效果.     

Achieving political acceptability for new transport infrastructure in congested urban regions

This paper analyzes the efficiency and political acceptability of road pricing and infrastructure policies targeted at relieving urban congestion. It combines a stylized transport model of an urban road network with a model of the political process that incorporates interactions between voters, citizen interest groups and politicians to explore the possibilities to reach political acceptability for efficient transport policies. In a numerical illustration, the paper compares a set of pricing and investment policies in terms of efficiency and acceptability. The illustration shows how conflicting interests can lead to non-efficient policies being chosen.     

基于马尔可夫链模型的交通拥挤状态预测

交通拥挤严重影响了道路交通的安全性和运行效率,如何对交通拥挤状态进行判别,并预测下一时刻交通状态的变化趋势,是提高交通管理水平的一个关键.利用马尔可夫链建立了交通状态预测模型,实例表明该模型对短期交通状态预测具有良好的适用性.     

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为了及时发现和预警城市交通高峰时期的偶发事件,研究了态势监控的城市交通拥堵动态跟踪问题.对交通拥堵的相关属性、变化规律、空间分布以及判别方式等进行综合研究的基础上,分析了道路交通流的非线性动力学特征,建立了基于时空分布的路网交通拥堵态势监控的动态预警模型,提出了解决城市路网交通拥堵的方法,达到了充分利用交通资源、疏导交通、缓解交通拥堵的目的.该模型在对占有率、速度、流量三个基本交通流参数进行处理获得新的交通拥挤判别指标基础上,通过形态识别模型对拥堵状态进行判定.实例分析表明,该模型为缓解城市交通拥堵问题、提高城市交通管理水平、改善道路交通安全形势等具有重要的理论意义和应用价值.