Numerical experience with diagonalization algorithms for asymmetric demand traffic assignment

This paper reviews the concept of a diagonalization algorithm for use in solving traffic network equilibrium problems for which the arc cost and/or the origin-destination travel demand functions are asymmetric. Such functions are known to occur in realistic settings involving multiple modes or users. The computational performance of this algorithm for different degrees of travel demand asymmetry is then explored by a detailed numerical experiment since no previous results of this type have been reported. It is found that, through the use of progressive stopping tolerances, the impact of high degrees of travel demand function asymmetry on the computational burden associated with finding a traffic network equilibrium may be mitigated; in effect equilibrium problems with high degrees of demand asymmetry are little more difficult to solve than perfectly symmetric problems.     

Spatial Cournot equilibrium: do branches matter?

This paper aims to contribute to the literature of Cournot spatial equilibria in two-dimensional spaces by considering branching. We study the case in which two firms compete on a circle and each one has the possibility of opening one or more branches. An innovative method—polar coordinates—is employed to obtain the complex profit functions. We show that there exists a symmetric subgame perfect Nash equilibrium where both firms place their n branches alternately and at the same distance from the center of the circle. Additionally, we show that this is, up to rotation, the unique symmetric equilibrium location.     

房地产市场博弈中政府行为及政策选择

近几年来,我国一些大城市房价持续走高,引发了一系列问题。鉴于此,政府出台了一系列的调控政策,但是收效甚微。其中一个主要原因就是在房地产的开发过程中,地方政府和房地产商由于一定程度的共利性而联合起来＂针对＂中央政府[1]。运用博弈理论分析房地产市场博弈中地方政府和中央政府的行为,通过计算得出纳什均衡解。最后提出相应的对策...     

城市交通中交通平衡模型的研究

本文讨论具有固定交通需求量的非对称连续交通平衡模型,即解决在给定的城市道路网络中,已知网络中的各交通小区之间在某时段的交通需求量,探讨出行者遵循怎样的原则选择怎样的出行路线的问题。国外主要研究了道路网络中只有机动车一种交通方式的平衡模型。Dafermos 对单一用户的交通平衡模型给出了变差不等式的数学模型,并且给出求解模型的一种迭代算法。本文针对我国城市中有机动车和非机动车两种用户的混合交通结构,基于 Wardrop 平衡原则,提出了交通平衡模型的数学模型,并给出了其解的存在和唯一性条件。本文还给出了求解平衡模型的投影法算法。简化了 Dafermos的迭代方法,并最后给出了其线性收敛性。     

THE EFFECTS OF THE ANNOUNCEMENT AND OPENING OF LIGHT RAIL TRANSIT STATIONS ON NEIGHBORHOOD CRIME

ABSTRACT: The debate over crime and rail transit focuses on whether such investments “breed” criminal activities with new targets of opportunity or transport crime from the inner city to the suburbs. Yet, little empirical evidence exists on whether new rail transit actually does lead to increased crime rates around stations. In order to study this question, we test the relationship between crime and rail transit with the 2007 opening of the Charlotte light rail line. We use Geographical Information Systems software and micro‐level data on reported crimes to generate measures of criminal activity in and around light rail transit (LRT) stations. We then implement a quasi‐experimental before‐and‐after methodology using two alternate transit corridors to control for differences between neighborhoods that contain LRT stations and other neighborhoods. We find light rail does not actually increase crime around stations. Instead, we see a decrease in property crimes once the station locations are announced, which remains relatively stable after the light rail begins operating.     

大型复合型多路交叉口总体设计及交通组织

多路交叉口通常由环形交叉口来组织交通。随着交通量的迅猛增长,多路交叉口成为城市交通瓶颈,探讨多路交叉口的改善方案十分必要。随着城市轨道交通的建设,多路交叉口往往成为含机动车交通、公共交通、慢行交通的复合型交叉口。通过对多路交叉口的问题分析,提出区域改善和节点改善相结合的解决思路,进而提出具体改善措施,并通过武汉鲁巷广场的实际交叉口案例进行论证。     

市郊轨道交通站点周边居民购物出行研究——以上海为例

市郊轨道交通建设推动了上海郊区的快速城市化发展,人口在外围大量集聚,也促进了郊区商业的发展。通常情况下,市郊居民每月去市中心购买大件物品而在周边超市购买日常用品。然而随着轨道交通的发展和私家车保有量不断提高,购物出行特征变得更加复杂化。通过对上海市郊两个地铁站点的居民进行出行调查,研究发现:郊区居民对市中心购物的依赖性较强,轨道交通成为去市中心购物的主要交通方式;居民根据就近原则来选择大型超市,提供免费的超市班车可以增加超市的消费群体;改善地铁站点周边的出行环境,同时优化外围的公交服务水平,增加到地铁站的公交线路,可以引导小汽车出行转向轨道交通出行。     

Improving walkability for seniors through accessibility to food stores: a study of three areas of Greater Montreal

The aging of suburbs requires that pedestrian accessibility be favored in this type of environment, because walking is a key element in the quality of life of seniors. This article analyzes the potential for accessibility by foot in three inner suburbs of the Greater Montreal Area. Accessibility was calculated using walking distances throughout the street network. This analysis was complemented by an observation of physical-spatial characteristics likely to affect walking among seniors. Pedestrian accessibility is influenced not only by long travel distances but also by various obstacles that result from land-use decisions in favor of motorized travel on a regional scale. This article reveals the necessity for urban planners to find a balance between local accessibility by foot and public transit, and regional accessibility by motorized transport.     

A game-theoretic analysis of the government's role on the biomass supply chain construction

ABSTRACT

This research utilises a game-theoretic approach to model and analyse the biomass power supply chain. The problem of the government's policy-choosing is discussed based on the vertical interactions between the three players: the farmer, the biomass power plant, and the government. A sequential game with asymmetric information is established considering the core issues: whether the farmer supplies the biomass to the power plant, what the power plant's optimal purchasing price of the biomass is, and which policy the government chooses. The Nash equilibriums are obtained, and the factors affecting the Nash equilibriums are summarised. Based on the discussion of these factors, the model can be modified to mimic reality by some modifications. An extension will be to include more kinds of asymmetric information. Another extension will be to change the policy objective of the government. Special attention is devoted to the impact of the change of the policy objective, which is caused by the reality of the government's structure, on the Nash equilibrium results.     

GENERAL EQUILIBRIUM VS. OPTIMUM, AND THE ALLOCATION OF LAND FOR TRANSPORTATION IN A CLOSED INFORMATION-ORIENTED CITY WITH TRAFFIC CONGESTION

ABSTRACT This paper presents a general equilibrium model of the closed city. The households residing in the suburbs are able to supply labor for the firms in the CBD not only by commuting which causes traffic congestion but also by telecom muting which needs an input of telecommunication services. The laissez-faire equilibrium is compared with the optimum. We derive the equilibria by numerical computations using specific utility, production and congestion functions. The results show the allocation of land for transportation based on the social cost-benefit rule, which is different from the allocation of Mills and de Ferranti (1971). This indicates that in the optimum market equilibrium which is maintained by both a congestion tax and subsidy, the city is rather more suburbanized than expected on the basis of previous studies.     

Community-Based Planning as a Source of Political Change: The Transit Equity Movement of Los Angeles' Bus Riders Union

Metropolitan regions in the U.S. are increasingly turning to public transit to address the serious problems of air pollution and traffic congestion. But they may not be capable of simultaneously luring suburban commuters out of their cars while maintaining good access to dispersing metropolitan opportunities for people who cannot drive. After an expensive rail rapid transit system to the suburbs was built in Los Angeles, a grassroots citizen movement used a civil rights lawsuit to force policymakers to meet the needs of poor, minority bus riders in the inner city. This article demonstrates a link between politics and planning by first identifying the crucial political changes, using a model from social movement theory, then examining how planning skills were used by citizen activists when they induced these changes. It suggests a new direction for equity planning, in which practice is based in community institutions acting as a complement to government planning.     

城市轨道交通车辆全寿命周期成本分析

城市轨道交通已经成为现代城市交通体系的重要组成部分,并且正在逐渐融入我国的各个大中城市。车辆是城市轨道交通工程中的核心组成部分。目前城市轨道交通车辆采购招标比选时,仅仅考虑车辆采购价格,并不包括车辆全寿命周期各个阶段发生的成本,因此做出的决策只是局部最优,并不是整体最佳。论文对城市轨道交通车辆全寿命周期的阶段进行划分,并对城市轨道交通车辆全寿命周期成本进行了成本分解,在此基础上构建了城市轨道交通车辆全寿命周期成本模型。最后将城市轨道交通车辆全寿命周期成本模型应用于地铁A型车辆进行实例分析,得出结论为:车辆购置成本占车辆全寿命周期成本的51.68%,所以进行城市轨道交通车辆选型时应从车辆的全寿命周期出发。     

城际轨道交通与城市发展

对“城际轨道交通”概念进行了界定,认为它既不同于属于干线铁路的快速客运专线,也不同于城市轨道交通,是属于区域性交通的范畴;论述了区域性城际轨道交通的由来、特点及其在国内外的发展概况;概括了城际轨道交通对城市发展的六方面影响;引导城市建立起生态型城市结构;在经济发达地区的各大中城市间产生“同城效应”;可对市区人口进行有效疏散;可增加城市环境容量;能节约用地、促进城市土地开发;有利于解决大城市交通堵塞的难题。     

环境污染治理的博弈分析

针对环境污染治理过程中存在的信息不对称性 ,建立了政府环保稽查部门和污染企业的两种不完全信息动态模型 ,给出了各自的子博弈精炼贝叶斯纳什均衡 ,提出了为杜绝治污过程中存在的欺骗行为 ,政府及环保部门应采取的对策     

城市新区开发建设与公交优先的互动机制

文章指出了新区开发面临两大压力,即土地资源日益紧张甚至枯竭的压力和小汽车爆发式增长带来的道路交通拥堵的压力;提出了从新区规划、建设和政策三个层面建立新区开发与公交优先互动机制,并指出了其内涵和外延;重点从资源配置、路权区分、交通工程、需求管理、公交新模式、居住区规划、建筑设计等方面提出了新区公交优先发展若干关键举措。     

Spatial duopoly under uniform delivered pricing when firms avoid turning customers away

This paper studies a spatial duopoly under uniform delivered pricing when firms do not ration the supply of the good, thus extending to a spatial context the analysis of oligopolistic markets with no rationing. The paper shows the existence of the equilibrium in prices under different tie-breaking rules (TBR) and compare the features of the equilibria found under these rules, thereby allowing to highlight the importance of the choice of the TBR in studying these models. When consumers buy from the nearest firm in case of equal prices (efficient TBR), any symmetric price pair within a given range is a Nash equilibrium, with each firm serving exactly half of the market line. If demand in each local market is equally split between the firms charging the same price (random TBR), the only equilibrium price is the one that gives zero profits to each firm. The degree of competitiveness of the market crucially depends on the TBR. Under the efficient TBR, all (but one) price equilibria deliver positive profits to both firms. Under the random TBR, the market outcome is very competitive in that firms make zero profits. None of the equilibria found under any tie-breaking rule are allocatively efficient.This paper is based on my DPhil thesis at the University of York. I would like to thank Gianni De Fraja, Keith Hartley, Peter Simmons, Catherine Waddams, Xavier Wauthy and participants to the 1998 EARIE and ERSA conferences for helpful comments and discussion. The paper has also been improved by the very useful comments of two referees of this journal. The usual disclaimer applies.Received: January 2001 / Accepted: January 2003     

旋转非对称边坡三维安全系数计算

基于滑面正应力修正模式,推导出旋转非对称边坡三维极限平衡安全系数显式解答。首先假设三维滑面正应力的初始分布,然后乘以含2个待定参数的修正函数;根据滑体竖直方向力平衡、垂直滑动方向水平力平衡及对旋转轴力矩平衡的条件,导出关于安全系数的2次代数方程;得到三维安全系数的显式解。本方法不需考虑条柱间具体作用力,满足主要平衡条件,计算过程简单,可应用于实际边坡工程。     

重庆悦来生态城模式——低碳城市规划理论与实践探索

针对普遍运用的"超大街区"的规划方式不但影响步行环境和城市品质,而且易造成交通堵塞的问题,重庆悦来生态城规划结合"五个重庆"的发展战略以及场地复杂的地形条件,形成了充分体现公共交通优先、行人步行优先、结合轨道站点开发、人性化尺度空间以及城市文化特色的生态城市规划模式。介绍了以"小街区"和"城市格网"为基础的这一规划设计模式的理论与实践探索。     

Spatial competition with profit-maximising and labour-managed firms

The nature of the equilibria arising under spatial differentiation is investigated here in a duopoly model, where at least one firm maximises value added per worker. The study shows that if firms' objectives differ, there exists a subgame perfect equilibrium in pure strategies, which is possibly characterised by asymmetric locations. If both firms are labour-managed, there exists a (symmetric) subgame perfect equilibrium in pure strategies with firms located at the first and third quartiles, if and only if the setup cost is low enough. Otherwise, undercutting is profitable. Received: 16 March 2000 / Accepted: 15 March 2001     

高铁建设管理中危岩落石治理管控博弈分析

我国高铁项目建设中的危岩落石治理管控问题越来越受到参建各方的重视。从建设方的角度对高铁项目建设中危岩 落石治理管控的主要任务进行了阐述,分析了高铁建设管理各阶段参建各方的行为对危岩落石治理管控的影响,建立并求解 了建设方、设计方与咨询方的三方博弈模型,得出不同参数关系下的纳什均衡解,说明在项目建设前期至施工图设计阶段, 建设方制定办法,加大惩罚力度,加强对关键性工程的检查,提高监督成效,会减少设计方、咨询方不履职尽责的概率,有 利于危岩落石问题的根本解决。通过分析,对建设方采取适宜的策略督促各参建单位在危岩落石治理方面尽职尽责提出了具 有管理学意义的建议。