Vissim在城市交叉口信号配时方案优化中的应用——以“粤海门村”交叉口为例

城市交叉口车辆之间干扰频繁,加上信号配时不合理,使得车辆的延误时间过长,交叉口的通行量不高.以粤海门村交叉口为例,在交通流量数据调查的基础上,通过“等效交通量”方法优化信号配时方案,运用Vissim建立微观仿真模型,并对优化前后的配时方案进行仿真评价.仿真结果表明：优化方案使得交叉口人均延误时间下降了16.6％,停车时间下降了19.3％,平均排队下降了10.6％,通行量增加了2.4％.     

基于多目标配时优化模型和交通设计的城市交叉口协同优化研究

文章基于多目标配时优化模型和交通设计,旨在缓解城市道路交通拥堵。通过分析城市道路交叉口交通流特性和问题,关注交叉口车流流向、车流交织点以及配时合理性。在交通设计方面,提出将左转车道右置的渠化设计方案。在配时优化方面,建立了多目标优化模型,以延误、通行能力和停车次数为优化目标,以各相位有效绿灯时间、交叉口饱和度及周期时长为约束条件。通过遗传算法对模型进行求解,并用SUMO仿真软件评价求解结果。研究结果表明,交叉口的时空资源得到更有效的利用,明显缓解了交通压力,为城市道路交叉口的运行、管理和规划提供了参考。     

基于视频检测技术的交叉口车辆排队长度研究

为科学合理地解决城市道路信号控制交叉口机动车交通流通行能力的计算问题,在分析大量实测数据的基础上,提出了对信号控制交叉口描述强拥挤交通流的当量排队长度模型--OEQL模型和MAEQL模型的修正模型,所建立模型的预测结果更加符合实际交通状况。这些模型的建立,为更精确的描述机动车车流在信号交叉口的状态,优化信号灯配时奠定了基础。     

基于粒子群算法下的交叉口信号配时优化

为了合理地优化交叉口信号配时,通过分析交叉口的评价指标,建立了以车辆的平均延误、停车次数最小、交叉口整体通行能力最大、各相位有效绿灯时间和交叉口周期时长作为约束条件的数学模型。并通过改进前人研究基础上的动态加权系数,将多目标的非线性优化问题转化为单一目标的非线性规划问题,为了得出更科学稳定的解,提出了改善粒子群算法系统稳定性的2种方法,并将其与粒子群算法结合起来。然后以Matlab为求解工具,结合临邑市某一交叉口实例进行求解分析。最后的结果表明,在使用改进后的粒子群算法进行优化后交叉口通行能力较之现状提升了9%,延误下降了28%,停车次数下降了9%,且各项优化结果均优于Webster,改进后的算法在程序中运行300代,到216代才开始收敛,而未改进的算法稳定性较差,优化结果和收敛曲线则随着实验次数的变化而变化,最后的结论证明了该算法和模型的可靠性。     

基于视频检测技术的交叉口车辆排队长度研究

为科学合理地解决城市道路信号控制交叉口机动车交通流通行能力的计算问题,在分析大量实测数据的基础上,提出了对信号控制交叉口描述强拥挤交通流的当量排队长度模型——OEQL模型和MAEQL模型的修正模型,所建立模型的预测结果更加符合实际交通状况.这些模型的建立,为更精确的描述机动车车流在信号交叉口的状态,优化信号灯配时奠定了基础.     

单点信号交叉口通行能力和服务水平分析

本文分析了单点信号控制交叉口通行能力和服务水平的影响因素 ,揭示了交叉口通行能力与延误随信号周期长度变化的规律 ,从而得出交叉口延误最小、通行能力最大的信号周期的取值范围 ,提出了交叉口饱和度接近饱和或过饱和时的交通管理措施     

预防“死锁”的最大绿灯时间计算方法

目前,信号配时优化方法通常根据车辆排队等绝对信号配时时长,而对下游可容纳车辆等缺乏考虑。该方法在过饱和交通状态下往往形成"死锁"现象,针对该问题,文章从上游车辆数达辆与下游可容纳排队长度间的关系出发,运用交通波理论,计算出交叉口预防死锁现象的最大绿灯时间,为信号配时优化提供参考。     

基于Synchro的信号交叉口优化仿真研究

通过对西安市某信号控制交叉口进行大量实际观测,分析了该交叉口存在的问题并提出解决方案,运用Synchro仿真系统中信号配时优化模型、用于延误计算的百分比延误模型和服务水平模型,对解决方案进行了优化仿真分析,交叉口各项评价指标均得到明显改善,验证了改善方案的可行性。     

基于VISSIM交通仿真的交叉口信号配时优化研究

城市信号交叉口拥堵问题一直是制约路段整体通行效率的主要因素。本文以昆明市日新中路与前卫西路交叉口为例,根据交叉口高峰时段交通流量调查数据,通过实用信号周期法与Webster算法两种方法对交通配时进行优化,并利用VISSIM交通仿真软件对优化前后的交叉口进行模拟分析,论证交叉口配时优化的可行性。     

基于排队论原理的无信号控制交叉口运行状况分析

无信号控制交叉口以及路段行人过街运行状况的研究是城市道路交通安全研究的一个重要方面。通过调查分析,选取典型的交叉口作为研究对象,并结合排队论知识,建立了基于无信号控制交叉口的交通运行状况分析模型,通过对模型的应用分析,为城市道路无信号控制交叉口交通安全研究,提供了比较有效的方法,对城市部分无信号控制交叉口以及路段行人过街的交通组织优化有重要的意义。     

Development in Information and Communications Technology (ICT) Statistics at the Australian Bureau of Statistics

This paper outlines the ICT statistical developments that the ABS has undertaken over recent years. These developments have been on both the supply side (ICT industry) and the demand side (use of IT by sector). The content of ABS ICT surveys has changed significantly over the last few years and are expected to develop further in line with industry changes and emerging policy needs.
Recent developments in household collections have been the inclusion of IT use questions in the 2001 Census of Population and Housing and in various ABS social surveys such as Children's Participation in Culture and Leisure Activities. Annual business IT use surveys are now conducted and include topics such as Internet commerce and IT security. Biennial ICT industry surveys are conducted to provide data on ICT production, imports and exports, ICT industry employment, performance and structure information. An Internet activity survey is run every six months and provides regional Internet access details and infrastructure details on Internet service providers.
A major development for 2002–03 will be the compilation of an ICT satellite account. ABS intends to produce an ICT Information Development Plan to guide its future statistical development work in the ICT field.     

Value at Risk in the Suburbs: Eminent Domain and the Geographical Politics of the US Foreclosure Crisis

Several US counties and local governments have recently considered a novel solution to the foreclosure crisis. They plan to use eminent domain to compel the owners of mortgage debt—and specifically of private‐label mortgage‐backed securities—to sell the debt to the government at a price reflecting the loan's market value. The government would then restructure the debt and resell it to new investors. The plans are striking because—in contrast to both development‐driven eminent domain and the federal subprime bank bailout—they would force investors to assume asset devaluation and increased long‐term risk. Notably, the plans have emerged as an instance of financialization‐focused politics in suburbs and suburban cities of color, specifically majority‐black and ‐Latino/a suburbs. Local support for the plans, we argue, is rooted in the long‐term disinvestment of these ‘suburbs of exception', which became targets of subprime lending and eventually sites where the ‘financial exception' has been localized. But these demographic shifts, fragmentation and fiscal pressures have at the same time created a suburban political terrain in which the plans have gained their strongest political support.     

Towards a Theory of Serendipity: A Systematic Review and Conceptualization

Serendipity – the notion of making surprising and valuable discoveries – plays a major role in the success of individuals and organizations alike. Previous research has established the importance of serendipity and identified important individual- and organizational-level antecedents. However, the literature has been dispersed and the boundaries of the concept have been blurry, leading to a lack of conceptual clarity and structure, and thus limiting validity and managerial actionability. Based on a systematic literature review, I synthesize existing management-related research on serendipity and explicate the emergence and composition of serendipity in the organizational context. I first identify three necessary conditions that differentiate serendipity from related concepts such as luck or targeted innovation: agency, surprise, and value. Then, I draw from the literature on sensemaking, event-based theorizing, and quantum-based approaches to management to conceptualize the process of cultivating serendipity in the organizational context as a process of enabling potentiality and materialization, and develop a multi-level theory of (cultivating) serendipity. This conceptualization contributes to our collective understanding of how, why, and when (i.e., under what conditions) organizations can leverage the value in the unexpected, which opens up fruitful avenues for further research.     

Accountability of NGOs in Bangladesh A critical overview

NGOs in Bangladesh have been recognized as effective change agents in the socio-economic arena throughout the world. Their contributions in micro credit, non-formal education and primary health care are widely known. NGOs play a significant role in society. NGO accountability, as a result, has become a critical issue. NGO accountability in Bangladesh has been examined here in relation to patrons, clients and themselves. Of the three relationships only accountability to patrons is in a near satisfactory state. Accountability to clients is handicapped by lack of opportunities of beneficiaries to participate meaningfully in NGO policy making. Accountability to themselves is adversely affected due to the adherence to a strictly hierarchical system and the influence of founding and charismatic NGO leaders.     

Towards an Asian model of human resource management? A comparative analysis of China,Japan and South Korea

There has been much discussion regarding the possible decline and weakening of national systems of human resource management (HRM). Yet, culture and institutions are often cited as the major stumbling blocks to this outcome. Such constraints may dissipate in the analysis, particularly if ‘regional clusters’ are considered where geographic and cultural closeness and ‘openness’ to similar economic pressures exist. In such cases, it might be postulated that convergence in HRM will occur. We argue that China, Japan and South Korea represent such a cluster. This article examines these countries, to see if a degree of convergence is taking place and if it is towards an identifiable ‘Asian’ model of HRM. A model of change is presented that distinguishes between levels of occurrence and acceptance. Details of the development and practice of HRM in each country are then set out. The article ends with a discussion and implications section and a brief conclusion.     

The Creation of the Office for National Statistics

A new Office for National Statistics was created in the United Kingdom in 1996 following a series of developments designed to strengthen the relevance and integrity of statistics. This paper describes these fundamental changes and sets out a blueprint for future progress. It also sets current developments in the United Kingdom in an historical and international context.     

What helps? Women engineers' accounts of staying on

We have considerable understanding of the obstacles that women engineers encounter and the reasons that they leave the field, but we know less about what enables them to remain. Adopting an interpretivist approach, this article examines how a group of British women engineers in two FTSE 100 companies account for “staying on” in their male‐dominated work settings. We delineate four specific forms of help that facilitate women's retention in the field. We argue that exposure to help leads to women developing a habitus that enables them to continue working in engineering. To conclude, we draw on our findings to outline HR practices that will facilitate supportive relationships in the workplace and pave the way towards developing more positive organisational climates.     

论现代物流企业的发展观

物流业经过诸多年的发展目前已经成为最热门的行业之一,物流企业的注册数量也与日俱增,达到前所未有的规模。毋庸置疑,任何企业都希望自己迅速做强做大,并成为真正现代物流企业的典型代表,要实现这一目标一个首要问题就是要解决现代物流企业的发展观问题。     

浅谈大体积混凝土裂缝的控制

大体积混凝土的裂缝问题是实际工程中长期困扰工程技术人员的问题,其控制技术的研究是混凝土结构研究的热点问题,具有重大的学术价值和潜伏的工程背景。     

Supply Chain Strategies in the UK Fashion Industry—The Rhetoric of Partnership and Realities of Power

This paper focuses on the fashion industry, one characterised by issues such as dramatic shifts in the scale and power of major retail buyers in the market, the advent of retailer own brands, and the nature of sourcing and supply chain decisions, issues that are increasingly global in nature. The aim of this research is to explore the nature of relationships between UK high street multiple fashion retailers and their contracted suppliers, many of whom are entrepreneurial firms by most definitions of the term. Four core themes emerge from the literature and provide a framework for the research, namely, power, process, partnership, and people. The research approach was qualitative, and conducted over a period of twelve months. The paper ends with an agenda for future research.