城市规模、空间距离与城市经济吸引区——一个简单的经济地理模型

本文从经济运行的微观基础出发，构建了一个简单的经济地理模型，并以此为基础对城市经济吸引区的相关问题进行了初步的探讨，解释了由“引力法则”和断裂点理论推导出的两个经验性推论：一是两个相邻且规模相等的城市其经济吸引区分界线为二者连线的中垂线；二是对于两个相邻但规模不相等的城市，则小城市的经济吸引区可能处于大城市吸引区的包围（或部分包围）之中。     

Use of Statistics in the Monetary Policy of the Czech National Bank: The Case of a Country in Transition

In the presented text the authors judge the importance of statistics in the monetary policy of the Czech National Bank (CNB) over the course of the economic transformation process, with particular consideration of changing statistical needs and the possibilities and limits of statistical data exploitation in the monetary analyses. The importance of statistics lies on the level of collection and processing of statistical information and on the level of use of statistical methods to analyse data. Since the start of the 1990s the requirements for statistics were significantly influenced by monetary policy. In the period 1990–1997, monetary targeting was the primary influential factor. Since 1998, the monetary policy is influenced by inflation targeting. Statistical priorities switched from monetary data to economy and financial market data. Much progress has been made in the use of statistical methods for analysing data. Statistics available at present cover the CNB's standard monetary-policy requirements and are on par with those in developed countries. Its further development will reflect the standard changes taking place in the more advanced countries.     

On modeling incentive systems which utilize pollution charges for pollution abatement

This paper examines a scheme of economic incentives for environmental protection, in which spatially differentiated pollution taxes are in use in compensating the pollution abatement costs. A simple mathematical model is described which determines an incentive system that encourages polluters to reduce the discharges to an acceptable level of ambient quality standards in a cost-effective manner. It is shown that the vector of pollution charges has to be proportional to the marginal abatement cost vector, but is smaller than the latter in magnitude. It is demonstrated that a necessary incentive effect may be achieved even if the total pollution charge is much lower (about three times) than the total abatement costs. It is also estimated how this charge incentive system reconciles conflicting criteria of cost-effectiveness and of equity. These conclusions are verified by numerical experiments with real data.     

现代服务业：上海经济增长的新动力

本文通过经济增长弹性与就业弹性两个指标,对上海"十一五"规划中提出将优先发展的现代服务业及其主要子行业在上海经济增长中的作用进行了研究。分析认为目前上海第二产业与第三产业对经济的拉动力相当。而现代服务业的拉动力大于传统服务业。近年来,现代服务业的就业弹性均值较大,同时弹性的波动变化很大,这是上海GDP就业弹性近几年波动增大的主要原因。同时,通过对现代服务业中主要子行业的分析,发现现代服务业子行业间就业弹性的变动有着高度的正相关,这将增加现代服务业就业弹性波动对于上海GDP就业弹性波动的影响。     

Preventing HIV in injection drug users: exploring the tradeoffs between interventions

Injection drug users (IDUs) transmit the human immunodeficiency virus (HIV) via both needle sharing and sex. Available interventions for this population have varying costs and effectiveness and focus on different risk behaviors. In this analysis, we look at two interventions. One is inexpensive, broad-based and provides modest risk reductions (street outreach (SO)); the other is narrowly focused, expensive and relatively effective (methadone maintenance). This analysis explores the effects of population risk behavior, intervention effectiveness, intervention costs, and decision constraints when allocating funds between these two interventions to maximize effectiveness. We develop a model of the spread of HIV, dividing IDUs into susceptibles (uninfected) and infectives, and separately portraying sex and injection risk. We simulate the epidemic in New York City for time periods from the mid-1980s to the early 1990s, and incorporate the behavioral effects of two interventions performed singly or in combination to find the allocation that maximizes the number of infections averted in the IDUs and their noninjecting sex partners, assuming interventions have increasing marginal costs. We find that the optimal allocation nearly always involves spending the maximum allowable amount on SO. This result is largely insensitive to variations in risk parameters, intervention efficacy, or cost. The model's structure, however, makes clear that many factors contribute to this insensitivity, namely the scope of the interventions, the dual drug/sex nature of HIV risk in the population, the asymmetry of sexual risk for men and women, and the potential benefits to nonIDUs.     

Industry evolution and R&D externalities

R&D externalities can imply ranges of aggregate increasing returns to scale in R&D. As a consequence several equilibria can exist involving different numbers of firms and different R&D investment levels. In a theoretical model the equilibrium dynamics are analyzed, showing that cyclical fluctuations of the number of firms and R&D investment may be expected, and that the long-run equilibrium is highly sensitive to investors' initial beliefs. The model is tested empirically using a unique database comprising competing firms in various R&D races.     

Forecasting economic time series using flexible versus fixed specification and linear versus nonlinear econometric models

Nine macroeconomic variables are forecast in a real-time scenario using a variety of flexible specification, fixed specification, linear, and nonlinear econometric models. All models are allowed to evolve through time, and our analysis focuses on model selection and performance. In the context of real-time forecasts, flexible specification models (including linear autoregressive models with exogenous variables and nonlinear artificial neural networks) appear to offer a useful and viable alternative to less flexible fixed specification linear models for a subset of the economic variables which we examine, particularly at forecast horizons greater than 1-step ahead. We speculate that one reason for this result is that the economy is evolving (rather slowly) over time. This feature cannot easily be captured by fixed specification linear models, however, and manifests itself in the form of evolving coefficient estimates. We also provide additional evidence supporting the claim that models which ‘win’ based on one model selection criterion (say a squared error measure) do not necessarily win when an alternative selection criterion is used (say a confusion rate measure), thus highlighting the importance of the particular cost function which is used by forecasters and ‘end-users’ to evaluate their models. A wide variety of different model selection criteria and statistical tests are used to illustrate our findings.     

广西北部湾经济区发展战略探析

分析了广西北部湾经济区的发展现状,创造性地提出其发展要因,最后,基于发展要因提出经济区发展战略,以供决策参考。     

城市交通与城市空间结构演变

通过回顾城市交通和城市空间结构的发展演变过程,研究通过城市交通引导城市空间结构健康"生长"的有效途径,提出通过公共交通引导城市发展的TOD模式,以及适合中国特色的和谐城市形态和城市交通.     

人力资本与经济增长关系研究——教育投资对经济增长的贡献自上市公司的经验证据

知识经济时代经济增长所依靠的已不仅是货币资本,更重要的是人力资本,货币资本的获得和财富的积累都是由人力资本推动的。人力资本是现代经济增长与发展的源泉和动力,增加人力资本投资,提高人力资源质量,已成为促进经济发展的重要手段。从我国经济增长的影响因素看,人力资本作为生产要素对经济增长具有决定作用,人力资本投资对我国经济增长具有战略意义。本文对经济增长理论及人力资本理论进行了介绍,并运用实证分析方法探讨了教育投资对经济增长的贡献。