浅谈城市轨道交通供电系统的节能措施与经济运行

在当前城市化进程不断加快以及城市人口高速增长的过程中,城市内部所出现的环境污染问题以及交通堵塞问题等也越发严重,对于城市的可持续发展以及城市居民生活质量的改善产生了一定程度的影响。所以,在城市发展过程中,坚持可持续发展的理念是城市轨道交通发展过程中最需要贯彻的发展理念。在城市轨道交通运行过程中,供电系统是运行系统的核心,在实际工作中会消耗大量的能量,所以需要就供电系统的节能、经济与环保进行探讨。论文对此展开详细论述。     

中国城市集聚与扩散的转换规模及最优规模研究

以我国211个主要地级及地级以上城市为研究对象,其中包括除拉萨以外的30个省会城市、5个计划单列城市以及176个地级市.收集了1989-2003年及2000-2005年各城市的连续时间序列数据,构建了城市集聚与扩散的Panel-data模型,并运用该模型分别估算了各城市的相对规模收益和相对外部成本,然后通过收益与成本的对比分析,判断城市发展所处的阶段,找出城市以集聚为主向以扩散为主转换的城市规模.研究发现:目前,除上海市处于扩散阶段外,我国其它城市都处于以集聚为主的发展阶段,且在这些城市中,绝大部分城市的规模收益的增长速度要快于其外部成本.     

A Dynamic Analysis of Multiple-Center Formation in a City

An optimizing model of urban land development is presented where formation and growth processes of subcenters are described. The model determines the location of new firms and households so as to maximize the net rental revenue from land over the planning horizon. The conditions on parameter values for which subcenters can be formed are investigated by the simulation method. Furthermore, how the optimal subcenter location varies in response to changes in relevant parameters is examined.     

Do We Still Need Cities? Evidence on Rates of Innovation from Count Data Models of Metropolitan Statistical Area Patents

Evidence of the importance of urban agglomeration and the offsetting effects of congestion are provided in a number of studies of productivity and wages. Little attention has been paid to this evidence in the economic growth literature, where the recent focus is on technological change. We extend the idea of agglomeration and congestion effects to the area of innovation by empirically looking for a nonlinear link between population density and patent activity. A panel data set consisting of observations on 302 USA metropolitan statistical areas (MSAs) over a 10-year period from 1990 to 1999 is utilized. Following the patent and R&D literature, models that account for the discreet nature of the dependent variable are employed. Strong evidence is found that agglomeration and congestion are important in explaining the vast differences in patent rates across US cities. The most important reason cities continue to exist, given the dramatic drop in transportation costs for physical goods over the last century, is probably related to the forces of agglomeration as they apply to knowledge spillovers. Therefore, the empirical investigation proposed here is an important part of understanding the viability of urban areas in the future.     

Spillover effects on the sectoral returns for australian and New Zealand equity markets

In this paper, we examine the return and volatility spillovers, together with the trend spillovers on the sectoral equity returns for Australian and New Zealand markets. We find that the return spillovers of industrial, local and global shocks have a limited effect on Australian and New Zealand sector returns, whereas the volatility spillovers play a significant role on explaining the volatility of sector equity indices. Furthermore, we discover that the volatility spillover effects of the global and industrial shocks are greater in magnitude for explaining the volatility of the Australian sectors than those of New Zealand, particularly basic materials, oil and gas, technology and telecom sectors. By employing the trend spillover model, we find that the volatility spillover effects of global sector indices have been increasing over the volatility of the Australian sectoral returns until now. This finding proposes that Australian sector equity market is more integrated with the world than the New Zealand counterpart.     

浅谈公交优先对城市综合发展的作用

随着城市规模的扩大和城市人口的增加,城市交通的压力也正在不断加剧,公交优先的方向应当始终坚持。实行公交优惠票价政策,体现了社会资源共享的公平性和经济合理性,有助于缓解交通拥堵,减轻大气污染保护环境,也有助于建立和谐社会,促进城市繁荣和城市综合发展。     

知识溢出:对研究脉络的基本回顾

自20世纪60年代以来知识溢出问题获得了大量研究,其研究成果主要来自经济学和区域与城市研究特别是经济地理学,本文对这两个学科在知识溢出方面的主要研究脉络进行了梳理,描述了经济学观察单元从企业转向空间的必然性,以及区域和城市研究对知识溢出问题研究的主要方面。     

城市空间互补与城市交通问题

聚集效应主要决定于城市区域空间之间的互补性,而与土地价格不存在互为因果的关系.城市区域空间互补性越强,聚集经济越大,资源空间布局越有效率,城市通勤距离也越短.由此才可以形成有效率的城市多中心空间形态.大都市交通问题的根源在于城市资源空间布局的非互补性.     

城市交通拥堵的系统动力结构分析

城市交通拥堵是当前我国很多城市在发展过程中所面临的难题。虽然人们从理论和实践两个方面都在做着积极的探索,但至今尚没有找到统一的理想解决方案。从系统动力学的角度出发,选取五个最基本的因素组建城市交通系统模型,并根据城市发展与交通演变之间的相互作用关系构建了城市交通系统动力结构模型。利用该结构模型,对产生城市交通拥堵的机理进行了分析,提出了优化发展城市交通系统,解决城市交通拥堵的五点建议,并对威海城市交通发展进行了实例分析。注重对问题的宏观把握,构建了一个研究城市交通系统演变规律的基本理论框架,这对城市交通系统的进一步细化研究具有一定的参考价值。     

Competition and nationally optimum resource allocation under the presence of urban traffic congestion

The present paper compares the market city size and the socially optimal city size in a model which allows for traffic congestion. It establishes that under the assumptions of constant returns to scale and perfect competition for commuter train companies, market forces alone will produce optimality in traffic congestion, in resource allocation for traffic facilities, and in the city size. The notion of optimality in this paper is in the sense of maximizing the welfare of the entire nation, rather than that of the city residents.     

Foreign Direct Investment and Managerial Knowledge Spillovers through the Diffusion of Management Practices

Although managerial knowledge spillovers have long been claimed to be a major benefit of foreign direct investment (FDI), such spillovers have not yet been systematically analysed. This paper adds to the literature by analysing the nature and extent of managerial knowledge spillovers from FDI through the diffusion of management practices. Taking into account the tacit and explicit elements of management practices and distinguishing between industry and non‐industry specific practices, the paper identifies different types of spillovers and discusses their transmission mechanisms. Evidence from establishment‐level panel data from the UK attests to the existence and significance of intra‐industry, linkage, and non‐linkage based inter‐industry spillovers of managerial knowledge from foreign to local firms, although the strength varies for different types of practices. The spillovers are geographically localized, especially in channels without supply chain linkages. Local firms are selective in the adoption of individual practices and the spillover effects are more significant at the cluster and management system level. Reverse spillovers from local firms to MNEs from industrialized countries appear to be limited despite significant spillovers of practices amongst local firms.     

The general equilibrium effects of congestion externalities

This is the second in a series of three articles on the topic of congestion externalities. We use an urban general-equilibrium model to compute two types of cities: the market-equilibrium city, in which congestion externalities occur, and the optimum city. The optimum city has a more dispersed distribution of employment, and a more concentrated distribution of residence. If the population of the city is fixed, the optimum pricing of transportation generates a per capita welfare gain of $3.78 per week. If the population of the city is endogenous, the internalization of congestion externalities causes the city to grow.     

WHY IS THERE A LACK OF EVIDENCE ON KNOWLEDGE SPILLOVERS FROM FOREIGN DIRECT INVESTMENT?

Empirical analyses of knowledge spillovers from foreign direct investment (FDI) offer mixed results; they find positive, neutral and negative FDI spillover effects. This lack of evidence mainly comes from the results of firm‐level panel data analysis. This is important since this approach seems to be the most appropriate for estimating FDI spillovers. The paper takes a look at recent substantive and methodological developments in FDI spillover analysis, which have brought some more optimistic results with regard to FDI spillovers, and can help in further development in this field. The main substantive development relates to the introduction of a broad variety of sources of firm heterogeneity (foreign affiliates as well as local firms) in the analysis. Others include differentiation between vertical (inter‐industry) and horizontal (intra‐industry) spillovers, and host country absorptive capacity for knowledge spillovers. Methodological developments relate to distinguishing between technological/knowledge and productivity spillovers, improvement of modelling and estimation methods, and an increased amount and quality of data.     

Nonparametric Employment Subcenter Identification

A two-stage procedure is proposed for identifying urban employment subcenters. The first stage identifies candidate subcenters as significant positive residuals in a smoothed employment density function. Subcenters are those sites that provide significant explanatory power in the second-stage, semiparametric employment density function estimation. The procedure can be applied to either aggregated or disaggregated data, does not require detailed knowledge of the study area, and is easily reproducible by other researchers. Results are presented for five previously studied cities—Chicago, Dallas, Houston, Los Angeles, and San Francisco—and a new one, New Orleans.     

FDI溢出对高经济产出区的增长影响

运用空间Durbin模型和极大似然估计技术,以1991-2012年大长三角25城市和大珠三角21城市面板数据,对比检验了FDI溢出与城市生产率间的基本关系。发现：FDI对本地城市增长正效应显著存在并随时间增强,其空间溢出显著但在二地区行为相反;空间依赖在城市生产率增长中有增强趋势,但在二地区方向相异;FDI提高了二地区城市增长的条件收敛速度;空间溢出在二地区的核心和外围都存在但表现各异并有不同演变。上述结论对于二地区引进FDI和促进城市发展具有重要政策含义。     

Spillovers of currency carry trade returns,market risk sentiment,and U.S. market returns

This paper examines the link between spillovers of currency carry trade returns and U.S. market returns. Following Tse and Zhao (2012), this paper hypothesizes that the magnitude of spillovers of currency carry trade returns is positively correlated with market risk sentiment and, therefore, has an impact on market returns. Using the G10 currencies and S&P 500 index futures, the empirical results present a high magnitude of spillover effects of currency carry trade markets. The empirical findings also show a significantly positive relationship between spillovers of currency carry trade returns and subsequent market returns. Furthermore, the results indicate that this relationship is stronger in bear markets than in bull markets. Finally, our findings show that spillovers of currency carry trade returns significantly affect the subsequent transition probabilities of market returns.     

Spillovers,absorptive capacity and agglomeration

I study knowledge spillovers in an industry where firms are heterogeneous in their ability to adopt knowledge (absorptive capacity). I set up a model in which firms choose locations anticipating potential gains and losses from other firms’ R&D activity. I apply the model to the US software industry and obtain the following results: the data supports localized knowledge spillovers; firms that have higher absorptive capacity are sorted into more agglomerated counties; ignoring firm heterogeneity leads to biased estimates of gains from spillovers; spillovers play an important role in explaining the geographic distribution of firms, but only within regions with high R&D activity.     

The topography of metropolitan employment: Identifying centers of employment in a polycentric urban area

While it is well recognized that US metropolitan areas are polycentric, there is little consensus as to the appropriate method for identifying concentrations of employment within them. Existing methods suffer from strong assumptions about parametric form, misspecification, or reliance on local knowledge to calibrate model parameters. This paper introduces a new nonparametric method for identifying subcenters. Results indicate that this, more flexible, nonparametric approach yields greater accuracy with regard to both urban and suburban centers compared with other approaches. This approach should provide better data for the numerous topics that depend on the spatial accounting of employment within metropolitan areas.     

On the distribution of city sizes

The city size distribution in many countries is remarkably well described by a Pareto distribution. We derive conditions that standard urban models must satisfy in order to explain this regularity. We show that under general conditions urban models must have (i) a balanced growth path and (ii) a Pareto distribution for the underlying source of randomness. In particular, one of the following combinations can induce a Pareto distribution of city sizes: (i) preferences for different goods follow reflected random walks, and the elasticity of substitution between goods is 1; or (ii) total factor productivities of different goods follow reflected random walks, and increasing returns are equal across goods.     

城市公共交通与城市发展的适应性研究

随着我国城市化进程的加快,城市机动车数量也急剧上升,我国能源储备不足与能源需求增加之间的矛盾日益凸显。此外,一系列城市交通问题也阻碍了城市的发展,如交通拥堵问题、大气污染等等。本文将从城市公共交通与城市发展的关系、适应性内涵、适应性评价指标等方面分别论述,初探城市公共交通与城市发展的适应性,为客观评价我国城市公共交通的适应性提供借鉴,为提升我国城市公共交通的服务水平提供参考。