我国城乡耐用消费品市场用户构成差异的研究——一个创新扩散的视角

创新扩散理论按照用户采用新产品的时间先后顺序将市场细分为创新者、早期采用者、早期大多数、晚期大多数和落后者五种类型。本文在扩散经典理论和中国市场特征的基础上,提出城镇市场和农村市场耐用消费品用户构成差异的假设。研究结果证实了全部假设:城镇的创新者比例显著高于农村,农村的早期采用者比例显著超过城镇,而各类型采用者的采用持续时间农村全面长于城镇。这些结论为更加深入地了解二元经济结构下中国市场的特征提供了有益启示。     

Land use externalities, open space preservation, and urban sprawl

Parcel data on residential land conversion are used to investigate how land use externalities influence the rate of development and modify policies designed to manage urban growth and preserve open space. Several “smart growth” policies are found to significantly influence land conversion, including a development clustering policy that concentrates development and generates preserved open space. In addition to directly affecting a parcel's hazard rate of conversion, this policy is found to affect neighboring parcels' conversion by generating a positive open space externality that hastens their development. The implication that the clustering policy could generate a more sprawled pattern of development is explored using spatial simulation.     

供应链管理中的两层规划算法

文章概述两层规划问题在交通领域、资源分配、委托代理以及供应链管理中的应用并讨论了线性和非线性两种两层规划问题,总结了极点算法、下降迭代、惩罚函数和分支定界算法,并进行了评价,最后进一步探讨了两层规划问题的应用前景和算法的发展方向。     

On the Use of Value Efficiency Analysis and Some Further Developments

The purpose of this paper is to discuss the use of Value Efficiency Analysis (VEA) in efficiency evaluation when preference information is taken into account. Value efficiency analysis is an approach, which applies the ideas developed for Multiple Objective Linear Programming (MOLP) to Data Envelopment Analysis (DEA). Preference information is given through the desirable structure of input- and output-values. The same values can be used for all units under evaluation or the values can be specific for each unit. A decision-maker can specify the input- and output-values subjectively without any support or (s)he can use a multiple criteria support system to assist him/her to find those values on the efficient frontier. The underlying assumption is that the most preferred values maximize the decision-maker's implicitly known value function in a production possibility set or a subset. The purpose of value efficiency analysis is to estimate a need to increase outputs and/or decrease inputs for reaching the indifference contour of the value function at the optimum. In this paper, we briefly review the main ideas in value efficiency analysis and discuss practical aspects related to the use of value efficiency analysis. We also consider some extensions.     

Linear Programming Models for the Measurement of Environmental Performance of Firms—Concepts and Empirical Results

I use linear programming models to define standardised, aggregate environmental performance indicators for firms. The best practice frontier obtained corresponds to decision making units showing the best environmental behaviour. Results are obtained with data from U.S. fossil fuel-fired electric utilities, starting from four alternative models, among which are three linear programming models that differ in the way they account for undesirable outputs (pollutants) and resources used as inputs. The results indicate important discrepancies in the rankings obtained by the four models. Rather than contradictory, these results are interpreted as giving different, complementary kinds of information, that should all be taken into account by public decision-makers.     

清单计价背景下投标报价策略研究

在建筑市场推行无底招标和清单计价规范的背景下，探讨由业主给定工程量，投标单位填报单价，最后经过验方计价，以单价结算的合同下，投标单位如何根据业主给定工程量可能的变动趋势，基于运筹学的线性规划理论，进行不平衡报价，最大化其收益。     

中国城市住宅市场的结构差异性分析

市场价商品房、经济适用住房和廉租房构成了目前中国城市住宅市场的供应体系.依据中国30个主要城市的房地产开发统计数据,选择吸纳率作为评价住宅市场供需均衡状态的指标,利用固定影响变截距模型,重点研究了商品房和经济适用住房供给结构的城市差异性.研究发现,在城市住宅市场中,经济适用住房市场和商品房市场具有很强的相关性.作为具有政府资助性质的经济适用住房建设,存在典型的地域性特征,其政策的设定和实施会对整个住宅市场产生影响,地方政府应在利用比较全面的住宅市场指标体系进行综合分析基础上,制定适合本地的经济适用住房政策.     

城市可持续发展能力成长过程理论解析

城市可持续发展是国家和地区可持续发展的核心和关键，城市可持续发展能力则是城市可持续发展的基础依托和潜在支撑。促进城市可持续发展能力的持续、快速、健康成长是实现国家和地区可持续发展以及构建和谐社会的必由之路。城市可持续发展能力相关课题的理论与实证研究必须着眼于城市可持续发展能力成长的时空过程周此，对城市可持续发展能力成长过程进行理论分析和探讨就显得尤为必要。     

Study on the planning principles of urban forest

The urban forest is the main body for the urban forestry management. There are not unified rules and standards for the planning of the urban forest yet in China. This paper discusses the planning principles of the urban forest： the priority of the ecological function, the adaptation to local condilions, the optimization in the whole system, the mutual dependence of forest and city, the culturecontinuance and recreation satisfaction, sustainable development and operability, etc. This paper takes Changsha as an example to elaborate the planning principles of the urban forest. Firstly, Changsba urban forest ecosphere is composed of the eco-garden, the round-the-city forest belt, the ecological isolation belt, the green channel, the landscape of the rivers and streams, the forest park, the biodiversity reserve and the eco-forest in suburb area. It aims to make every kind of ecological essential factors organically merge into the complex city ecosystem to build an eco-city, to strengthen the connection of wide-open space with various habitats spots, to promote resident＇s accessibility, to perfect landscape ecology, and to make full use of the ecological function of urban forest. When we construct the urban forest, we must optimize the comprehensive benefit and make the urban forest structure and the layout in the best condition in order to buiM the harmonious green city for both man and nature to realize the whole optimization of the city system by the complex functions of the urban forest in ecology, environmental protection, landscape, recreation, etc.     

天津市城市基础设施需求弹性测度研究

通过对相关文献和城市基础设施投资决策的政绩、寻租、效率以及需求导向进行分析,并利用修正的鲍莫尔模型,可为分析居民需求弹性对基础设施投资倾向的影响提供了一个微观的理论框架。结合天津市基础设施建设的实证分析,从经济性基础设施和社会性基础设施两方面,探讨基础设施需求弹性反映出的结构差异。