江苏粮食生产地域分化的耕地因素分解

以粮食产量计算模型为基础,将粮食生产分解成耕地利用的数量、结构、强度、广度4个因子.以江苏省为例,从省域-分区域-地市等不同空间尺度,分析粮食生产的耕地因子过程,比较各地粮食生产变化的差异及其耕地利用变化的成因.结果显示:1990年代中期以来,江苏粮食生产区域分化显著,南部耕地大幅减少、有限耕地的生产功能减退,导致粮食生产全面萎缩;中北部耕地利用集约度提升,粮食生产功能总体趋于强化.影响各地市粮食生产变化的主导因子各有不同:粮食单产是连云港、盐城、宿迁、扬州、泰州5市粮食增产的主导因子,结构调整是南京、徐州、南通粮食减产、淮安粮食增产的主导因素;复种指数调减是苏州、无锡粮食生产衰退的首要因子.     

基于GIS技术的人居环境自然适宜性评价研究——以遵义市为例

以公里格网为基本单元,基于GIS技术,建立包括地形起伏度、温湿指数、水文指数和地被指数的人居环境自然适宜性评价模型,系统评价遵义市不同地区的人居环境自然适宜性与限制性。研究表明,遵义市人居环境以适宜性为主要特征,自然适宜程度整体呈现出由西北向东南递增的趋势,其中44.41%为一般适宜区、54.13%为比较适宜区以及极小比例为临界适宜区;遵义市人居环境自然条件较好,地形、地被、水文和气候对人口分布的限制性不明显,其中地形条件对人口分布的限制性最强,其次是地被条件。     

我国城市土地优化配置研究演进与展望

通过文献分析法,将我国城市土地优化配置研究发展历程划分为3个阶段：城市土地优化配置研究的萌芽阶段（1978—1993）;城市土地优化配置研究框架的初步形成阶段（1994—2000）;城市土地优化配置技术和方法的发展阶段（2001年以来）。研究认为我国城市土地优化配置研究受到经济体制改革的影响,研究逐渐从优化配置的理论过度到优化配置技术和方法,城市土地利用空间配置的综合研究欠缺,城市土地优化配置的微观研究还有待加强。今后,城市土地优化配置研究包括城市土地空间优化配置、城市土地优化配置的外部效应、城市与区域土地利用关系等方面,应进一步加强和突破。     

基于PSR模型的广东省城市土地集约利用空间差异分析

将＂压力—状态—响应＂框架引入到城市土地集约利用评价指标体系中,采用主成分分析方法对评价指标进行赋权,对广东省21个地级市的城市土地集约利用水平进行了评价。结果表明,广东省城市土地利用集约度差异形成的主要影响因素是地理区位条件和经济发展水平,资源赋存状况也是重要的制约条件。城市土地集约利用是一个复杂的系统工程,不仅要注重提高土地利用的产出效益,还要重视系统压力状态的调节和系统反馈能力建设。研究也表明,PSR评价指标体系及主成分分析方法能较好地适应城市土地集约利用评价的需要。     

土地使用管制及其利益补偿研究:理论和实践意义

运用文献回顾以及微观经济学理论和方法,对土地使用管制的目的、功能、手段、效果、补偿等问题进行了探讨。对土地使用的限制是目前我国土地管理制度存在的突出和新的问题。研究认为,必要的管制是有益的,但是要审慎运用管制手段,并注重对权利主体的利益保护和必要的补偿。土地使用管制是政府配置土地资源、干预土地市场的一种方式。纠正土地使用的外部性、提供公共产品是管制的主要目的。土地使用管制的存在是必要的,但是人们必须注意加强对其效果的研究。这些效果有些是积极的,有些是消极的。土地使用管制本身是有成本的。随着社会的发展,土地使用管制方式越来越多样化,越具有弹性化和市场化。由于管制而给有关主体造成的影响可通过税、费或者补偿的方式予以再调整,以维护社会公平,并达到特定的社会目标。     

Endogenous market structures and contract theory: Delegation, principal-agent contracts, screening, franchising and tying

I study the role of unilateral strategic contracts for firms active in markets with price competition and endogenous entry. Traditional results change substantially when the market structure is endogenous rather than exogenous. They concern (1) contracts of managerial delegation to non-profit maximizers, (2) incentive principal-agent contracts in the presence of moral hazard on cost-reducing activities, (3) screening contracts in case of asymmetric information on the productivity of the managers, (4) vertical contracts of franchising in case of hold-up problems and (5) tying contracts by monopolists competing also in secondary markets. Firms use always these contracts to strengthen price competition and manage to obtain positive profits in spite of free entry.     

History-based price discrimination and entry in markets with switching costs: A welfare analysis

We analyze history-based price discrimination in an asymmetric industry, where an incumbent, protected by switching costs, faces an entrant who does not have access to information about consumers’ purchase histories. We demonstrate that consumer surplus is higher with uniform pricing than with history-based price discrimination. We find that the entry decision is invariant to whether the incumbent implements history-based pricing or uniform pricing. This implies that the potential abuse of market dominance imposed by history-based price discrimination is exploitation, not exclusion. Finally, we establish that the profit gain to the incumbent from history-based pricing exceeds the associated loss to consumers.     

Estimating demand curve in the Korean VoIP telecommunications market

The VoIP (Voice over Internet Protocol) market in Korea is showing rapid growth since domestic carriers initiated the service in 2006. These carriers are now seeking new revenue sources from various convergence services and are increasing investment into VoIP. In particular, local exchange carriers (LECs), formerly reluctant to invest in technologies that would cannibalize their local telephone revenue, have started to invest in VoIP, in recognition of the current convergence of media and the telecommunications industry, as well as in the face of intensifying competition. In this study, we determined that VoIP call rates and landline telephony call rates were the most important factors affecting VoIP call demand, in addition to network externality. We also verified that landline telephony is no longer a supplement to VoIP, but rather, a substitute that has considerable influence on VoIP call demand. Empirical evidence is expected to be considered in policy decision making on current issues in the IT industry, such as access prices or competitiveness assessment. The current empirical analysis on the Korean VoIP industry and the adherence to lessons learned from policy enforcement should provide valuable information to countries seeking to develop their own VoIP industries, as well as to businesses developing new strategies based on the VoIP market.     

The interaction effect of strategic orientations on new product performance in the high-tech industry: A nonlinear model

Innovation and market orientation are two strategic orientations or business philosophies that can guide a company in its business activities. Although the interaction effect of these two strategic orientations is conceptually recognized as a critical factor for new product's success, empirical results are mixed. This paper examines this issue in terms of innovation orientation, two types of market orientations (responsive and proactive), and new product performance. Based on a sample of 107 high-tech firms, the results of this study show that the interaction between innovation orientation and two types of market orientation yields different patterns of nonlinear responses for new product performance. Specifically, new product performance, when derived from the interaction between innovation orientation and responsive market orientation, is in the form of an inverted U, i.e., the interaction effect is contributory to firm performance until an optimal level is reached, and then the effect becomes detrimental thereafter. However, new product performance derived from innovation orientation and proactive market orientation is in the form of a U, i.e., the interaction effect is detrimental to firm performance until a threshold level is reached and then the effect becomes contributory thereafter. The different patterns of new product performance indicate that the costs and organizational learning effects of these two strategic orientation interactions are dissimilar. The paper concludes with a discussion of theoretical and practical implications of these findings.     

城市地价空间自相关分析——以宿州市为例

运用全局和局域自相关统计量及地统计学半变异函数分析方法,对宿州市商业和住宅地价的全局自相关、各项异性及局域自相关特征进行了全面分析.结果表明:在2 800m范围内,宿州市商业和住宅地价均存在较强的正自相关性且趋于高值集聚,随着相关距离的增大,地价半方差按球状模型曲线增长,自相关性逐渐减弱;在不同方向上,地价的空间自相关特征不尽相同,南北方向上的空间自相关范围要大于东西方向,但随机性较强,自相关程度较东西方向弱;在全局呈显著自相关的情形下局域地价也主要呈空间集聚格局,但部分地区表现出异质性.