技术进步对建筑业经济增长的贡献分析

应用柯布-道格拉斯生产函数和索洛余值法,对我国建筑业经济增长的贡献进行分析,阐明技术进步是促进经济增长的重要因素。建筑业要依靠技术进步提高国际竞争力,实现可持续发展。     

Energy inputs and crop yield relationship in potato production in Hamadan province of Iran

The aim of this study was to determine energy consumption and the relationship between energy input and yield for potato production in Kaboud Rahang region of Hamadan state. The data used in this study are collected by questionnaire. The results revealed that nitrogen fertilizer (39%), diesel (21%), seed (14.9%), water (7.5%) and manure (6.4%) consumed the bulk of energy. In the surveyed farms, average yield and energy consumption were calculated as around 28613.7 kg/ha, 92296.3 MJ/ha, respectively. The results also showed that energy ratio, specific energy and energy productivity were 1.1, 3.2 MJ/kg and 0.3 kg/MJ, respectively. An econometric model was developed to estimate the impact of energy inputs on yield by using parametric methods. For this purpose, potato yield, an endogenous variable was assumed to be a function of energy inputs: fertilizer manure, chemical, machinery, human, water for irrigation, diesel and seed. The empirical results indicated that variables: fertilizer, chemical, seed and human were found statistically significant and contributed to yield. Among statistically significant exogenous variables, seed, water for irrigation, chemical, human and fertilizer were ranked in terms of elasticities.     

Innovation in Industrial Districts: Evidence from Italy

The aim of this paper is to show that Italian manufacturing firms belonging to Marshallian industrial districts carry out a higher innovative effort than is usually acknowledged. The empirical analysis makes use of a panel of 1,218 district and non-district firms belonging to traditional sectors. Data refers to the years 1992 and 1995. We have estimated an augmented Cobb-Douglas production function. The estimates make it possible to empirically identify three different determinants of firms' productivity: (i) the intentional innovative activity; (ii) the “district effect”; and (iii) the joint district and innovation effect. The results show that firms' membership in industrial districts and product innovations are key factors in explaining the productivity of firms working in traditional Italian sectors.     

Implementing the Double Bootstrap

The single bootstrap already is popular in economics, though the double bootstrap has better convergence properties. We discuss the theory and implementation of the double bootstrap, both with and without the pivotal transformation, and give detailed examples of each. One example is a nonlinear double bootstrap of a Cobb-Douglas production function, and explains the use of Gauss-Newton Regressions as a device to decrease computational time. Another example is double bootstrapping elasticities from a translog production function.     

安徽省人力资本投资对经济增长影响实证分析——以教育形成的人力资本为例

随着经济全球化,越来越多的人认识到,当今世界的竞争归根结底是科学技术和人力资本的竞争。利用修订后的柯布-道格拉斯生产函数,对安徽省1978～2008年经济增长的各要素进行计量分析,实证结果显示安徽省的劳动力投入、物质资本投入,以教育形成的人力资本投入对经济总量均为正相关,其中以教育形成的人力资本的弹性系数最大,其投入量每提高1个百分点,将带动经济增长1.8199个百分点。因此,就目前安徽省的经济发展状况来说,增加以教育形成的人力资本的投资,将对各地的未来经济发展起到至关重要的作用。     

信息化对经济增长的作用探析

信息化就是信息资源、信息技术、信息产业在国民经济和社会环境中不断丰富、不断提高的过程。它通过信息要素内生化、产业结构优化和促进劳动生产率提高来带动国民经济增长。指出随着信息化程度的提高,它日益成为除劳动力、资本要素外,推动经济增长的第三种动力。提出了我国加快信息化发展的政策建议。     

企业经营者激励的棘轮效应问题研究

针对基本棘轮效应模型存在的不足之处,引入柯布-道格拉斯生产函数,重新建立了企业动态激励的棘轮效应模型;基于系统论观点,将第1期产出对第2期产出的影响写入模型中,结果证明这将有助于弱化对经营者进行动态激励过程中的棘轮效应;提出了一系列有利于企业经营者才能发挥的长期动态激励措施.     

基于最速下降法的常州物流业优化问题研究

随着我国经济的快速增长,物流业逐渐发展成国民经济的新增长点。世界各国物流业的发展历史表明,现代物流与区域经济之间存在着密切的联系,两者相互促进、协同发展。物流是区域经济协调发展系统的重要构成要素,是区域经济协调发展系统形成与发展的一种主导力量。文章采用柯布-道格拉斯生产函数模型进行研究,并且运用最速下降法对城市农产品物流、工业品物流、进口货物物流、居民物流等在城市物流业中的发展趋势进行分析,从而确定城市物流业的发展方向,为常州市物流业优化提出合理建议。     

投入－产出系统生产要素动态匹配状况评判初探

探讨了生产要素系统组合效应概念和基本特性，进而建立一种投入－产出系统生产要素动态匹配状况的实证评价判据和方法，最后给出对实际系统的评判分析案例．     

Energy use patterns and econometric models of grape production in Hamadan province of Iran

This paper examines the energy use patterns and relationship between energy input and yield for grape production in Malayer region of Hamadan Province. Data from 50 farmers were collected using a face-to-face questionnaire method. In the surveyed vineyards, average yield and energy consumption were calculated as 18,530 kgha⁻¹ and 45,213.66 MJha⁻¹, respectively. Among input energy sources, fertilizers, electricity and farmyard manure contained highest energy shares with 37.25%, 19%, and 17.84%, respectively. The energy ratio and energy productivity were found to be 4.95 and 0.42 kgMJ⁻¹.Three econometric models were developed to estimate the impact of energy inputs on yield. The results revealed that impact of chemical, fertilizer and water on yield were significant at 1% probability level. Also, indirect and non-renewable energies were found to be rather high. Sensitivity analysis indicated that among the inputs, chemical has the highest MPP value of energy inputs. RTS (returns to scale) values for grape yield was found to be 2.15; thus, there prevailed an IRS of grape for estimated model. The net return was found to be positive as 2810.56 $ha⁻¹ for grape. The benefit-cost ratio was calculated as 2.08.