都市聚落系统的形成规律——递增报酬与幂次法则的计算机与数理仿真

幂次法则是一个普遍存在于自然科学与社会科学界的现象,在都市体系中亦可观察到此一现象。过去的文献仅仅对于幂次法则现象进行了观察和解释,并未能完整地解释其形成的机制。本研究尝试由复杂理论中“递增报酬”的观念来探讨幂次现象的成因,采用计算机程序来仿真都市聚落体系形成的过程,并观察递增报酬与幂次现象之关系。该仿真包含了3 种不同的区位发展吸引模式,分别为相邻关系、规模吸引以及同时考虑规模与相邻的混合模式。计算机仿真显示：① 规模吸引与混合两种模式比相邻吸引模式能够更好地解释都市聚落的成长;② 依照递增报酬法则而仿真形成的都市聚落,与幂次现象呈高度相关。随后的数理仿真演算显示,幂次法则为一统计上的普遍现象,但在递增报酬等经济因素驱动下的都市聚落体系结构与真实的状况较为吻合。因此我们推测,递增报酬极可能是形成真实世界幂次现象的机制之一。     

The Production of Investment Returns in Spatially Extensive Financial Markets

Investment returns are produced by combining financial assets with human capital, the decision-making protocols of investment houses, and the electronic infrastructure that supports the flow of information about investment. At the center of the production process stand senior managers; their power and authority in the production process is fundamental to the performance of investment organizations. This article provides a model of the production of investment returns in financial centers and spatially extensive financial markets. We begin with Coase's theory of the firm but go beyond models of the firm that represent commodity-producing industries. Having substantiated the model of investment management, it is applied to institutions that seek investment returns in geographically extensive financial markets. Operating in financial markets at a distance from home jurisdictions is an increasingly important aspect of investment management. Given recent turmoil in global financial markets, financial houses have sought higher rates of return from markets in which they have little direct experience. At issue is how different types of financial organizations (large and small, growing and declining) produce investment returns in this new environment.     

机载LiDAR数据的多回波信息分析及应用研究

本文通过分析机载LiDAR系统获取的激光数据的多回波特性,阐述了多回波信息对地物类型信息的揭示作用,并将多回波特性用于减少参与滤波的激光脚点数量。实验证明,本文提出的滤波方案,可以预先剔除掉大部分的植被激光脚点和部分的建筑物激光脚点,既减少了参与滤波的数据量,又可以改善滤波算法对建筑物和植被的滤除效果。     

规模报酬递增与京津冀都市区经济增长

借助Verdoorn法则,并将其拓展至区域经济研究框架,以京津冀都市区为研究区域,将其经济增长过程分为1995～2000年、2000～2007年及1995～2007年3个时段,采用Spa-tial Durbin Model和空间贝叶斯异方差回归模型将空间自相关和空间异质性纳入传统Ver-doorn法则的经验估计中,得到...     

新经济地理学与传统经济地理学之比较研究

自20世纪90年代以来，藤田、克鲁格曼、维纳布斯等以迪克西特和斯蒂格利茨垄断竞争模型为基础，用不完全竞争、报酬递增和市场外部性等理念构建新的经济地理模型，掀起了一场“新经济地理学”革命。新经济地理学在理论基础、研究特点和方法等方面与传统经济地理学表现出明显不同，其理论创新受到经济学界和地理学界的普遍关注。但是，也有一些学者对它提出了同样引人注目的抨击。通过对新经济地理学与传统经济地理学进行比较，对一些重大理论假设、研究方法与特点进行简要分析，有助于廓清对新经济地理学与传统经济地理学之异同的正确认识，以期推动新经济地理学的理论研究与应用以及新经济地理学与传统经济地理学领域的学术交流。     

利用资本市场 加速推进GIS产业的发展

我国GIS产业面临严峻的挑战与发展的机遇 ,在GIS产业的发展中 ,应学会灵活运用资本市场与GIS产业的关系 ,利用资本市场完善GIS企业制度、筹措资金、实现GIS企业的跳跃式发展     

The mechanism of farmland marginalization in Chinese mountainous areas: Evidence from cost and return changes

Journal of Geographical Sciences - Farmland marginalization has become the main trend of land-use change in the mountainous areas of China. Using annual survey data of major agricultural production...     

A PATH-DEPENDENT MODEL OF INVESTMENT AND EMPLOYMENT FLOW IN A LARGE ECONOMY IN A PROCESS OF INTEGRATION

This paper meant to analyze the spatial evolution of a large country in its process of integration with the world economy in general, and, to look into the possible effect of China‘s accession into WTO on the future development of its spatial economy in particular. Through an approach of increasing returns, external economy, product differentiation and path-dependence, with foreign trade costs incurred by different regions within the large country discriminated, a model of investment and employment flow is developed as a simulation of a large country‘s process of integration with the world economy. The modeling indicates that in the process of integration, as there exist differences in foreign trade costs among different regions within the large country, either the spatial economy of the country deviates from its symmetric structure in autarky and falls into a core-periphery relationship, or the effect of industrial agglomeration is reinforced, amplified and locked in, if the agglomeration had been started. The economic gap on either the aggregate or structural basis between different regions within the large country will increase rapidly as the integration proceeds.     

机载LiDAR数据的多回波信息分析及滤波方案

本文通过分析机载LiDAR系统获取的激光数据的多回波特性,阐述了多回波信息对地物类型信息的揭示作用,并将多回波特性用于减少参与滤波的激光脚点数量。实验证明,本文提出的滤波方案,可以预先剔除掉大部分的植被激光脚点和部分的建筑物激光脚点,这既减少了参与滤波的数据量,又可以改善滤波算法对建筑物和植被的滤除效果。     

新经济地理学及其展望

对新经济地理学的起源、发展、遭受的质疑及未来发展趋势做一简要的评述.经济活动的地理因素一直是许多经济学家、地理学家、规划学者以及区域科学家所关注的问题.20世纪80年代以来,以报酬递增、不完全竞争为假设前提,以数学建模为分析工具的新经济地理学的研究有了不断发展,但由于新经济地理学的核心模型在许多方面显得过于简单,受到了来自经济地理学、区域经济学和城市经济学的质疑和批评.有鉴于此,新经济地理学今后的研究除了考虑要素流动性、规模报酬递增、运输成本等关键因素之外,至少有3个可供未来研究的方向:扩展理论研究范围、加强实证研究、探讨新经济地理学的福利和政策涵义.