基于失效风险的建筑物预防维修成本模型优化

建筑物预防性维修成本的最优控制问题,是企业现代化经营管理的一个重要组成部分,直接影响到企业的经济效益。针对承受重复荷载作用的建筑构件,失效概率随服役时间增加而增大的实际情况,提出了失效风险的概念。采用役龄回退因子描述了维修后失效概率降低的程度,在此基础上推算出满足可靠度约束条件,适用于特定时间段非等间隔检测期序列,计算出单位维修周期内的检测次数。通过对维修成本函数的分析,建立了基于等失效风险状态的维修成本优化模型。为房屋物业管理部门进行建筑物的维修和更换决策提供参考依据。     

FDI企业对我国私营企业科技创新能力的影响研究

本文利用DEA-Malmquist指数分析方法对FDI企业与我国私营企业2003～2012年全要素生产率进行了测算,结果显示：FDI企业的全要素生产率及增长率都高于我国私营企业。说明FDI企业的科技创新能力要强于我国私营企业。其主要原因是FDI企业通过多种方式和渠道对我国私营企业的科技创新能力产生了重要影响。本文通过实证分析表明, FDI企业主要通过科技创新能力、市场集中度及分工地位对我国私营企业的科技创新能力产生作用。     

Estimation of investment costs in fish processing plants

Investment costs for fish processing plants are hereby presented along with a detailed analysis of different types of processes in relation to economies of scale.The cost-capacity factor for fish industry is estimated as 0.84, except for fish meal plants where the cost-capacity factor is 0.61.It is also discussed how technology, capacity and location in developed and developing countries can affect investment costs for fish processing plants, while cost-capacity factors remain unchanged.The concept of minimum limit for industrial capacity is included. Investment costs for minimum size plants or plants below minimum size are even greater than what would correspond to the correlation line. This is due to the need to incorporate one or more oversized pieces of equipment.     

医药企业技术创新的动力因素分析

目的提高我国医药企业的技术创新能力和增强我国医药企业的核心竞争力。方法从内、外两个方面对我国医药企业技术创新动力因素进行理论分析,从本质上阐述技术创新的动力机制。结果与结论我国医药企业技术创新动力不足,医药技术创新和科技成果迅速产业化的机制尚未完全形成,医药企业技术创新能力比较弱。     

New perspectives on farm size and productivity

The farm size and productivity debate has been limited by the focus on land or labor productivity, generally showing respective productivity advantages to smaller or larger sized farms. Our purpose is to provide new perspectives on the debate by bringing together evidence from a set of novel case studies in both rich and poor countries. Common to them are the adoption of total factor productivity (TFP) as the comparative performance measure, and the reliance on panels of farm micro data. The present article presents a synthesis of findings from five case studies in (i) Malawi, Tanzania, and Uganda; (ii) Bangladesh; (iii) Brazil; (iv) Australia; and (v) the United States. The preponderance of evidence from these studies suggests that there is no single economically optimal agrarian structure; rather, it appears to evolve with the stage of economic development. Certain farm sizes face relative productivity advantages, such as small farms in Africa. But with economic and market growth, that smallholder advantage will likely attenuate, moving toward constant and eventually increasing returns to size. Yet, importantly, small farms may be quite dynamic, and need not be a drag on agricultural growth until perhaps well into the development process.     

Do R&D and ICT affect total factor productivity growth differently?

We analyze the effect of ICT and R&D on total factor productivity (TFP) growth across different industries in Sweden. R&D alone is significantly associated with contemporaneous TFP growth, thus exhibiting indirect effects. Although there is no significant short-run association between ICT and TFP, we find a positive association with a lag of seven to eight years. Thus, R&D affect TFP much faster than ICT-investments. We also divide ICT capital into hardware and software capital. To our knowledge, this distinction has not been made in any previous study analyzing TFP at the industry level. The results show that lagged hardware capital services growth is significantly associated with TFP growth. Hence, investments complementary to hardware are needed to reap the long-run TFP effects from reorganizing production.     

巷道快速掘进技术在贵州省煤与瓦斯突出煤层中的探讨与应用

巷道快速掘进技术是一项系统工程。为了实现矿井高产高效,必须以巷道快速掘进技术为前提和保障。本文以贵州省为例,探讨了巷道快速掘进技术的研究现状及影响因素。针对贵州某矿突出综合检测指标经常超限、掘进速度慢等问题,采用了高压水射流割缝与瓦斯抽放边抽边掘相结合技术。研究表明:该项技术能有效削弱煤层突出危险性,大幅度提高瓦斯抽放量且巷道掘进速度提高了2~3倍。同时根据贵州省的本土情况,提出了针对性地建议和措施,能为巷道快速掘进技术的推广与应用提供一定的指导。     

因子分析中公因子提取方法的比较与选择

近代和现代统计分析方法中,因子分析是最重要的方法之一。因子分析中有7种提取公因子的方法,其中主成分法、极大似然法和主轴因子法是常用的方法。在着重解析这三种方法基本数学过程的基础上,对其适用条件和应用注意事项进行了比较,最后结合实例比较了不同公因子提取方法的结果,并对提取公因子过程中出现的问题给出了可能的解决办法。     

基于模糊综合评判的配电网运行风险评估模型及运用

本文从配电网运行的内部环境因素和外部环境因素综合考虑了影响其运行风险的各种不确定因素。通过确定风险因素集、指标集以及采用三角模糊数互补判断矩阵确定风险权重集,建立了配电网运行风险的模糊综合评判矩阵,并运用于配电网运行的外部风险评估。最后,通过实例证明了模型的可操作性。     

中国农业碳排放再测算: 基本现状、动态演进及空间溢出效应

探究创新要素流动对农业绿色发展的影响机制,合理引导创新要素流动,对推动农业现代化发展具有重要的现实意义。本文基于要素流动视角,在采用SBM-GML指数测算农业绿色发展水平的基础上,运用空间杜宾模型考察了R&D人员和R&D资本两种类型创新要素流动对农业绿色发展的影响及其空间溢出效应。结果表明：（1）中国农业绿色发展整体呈波动上升的态势,地区农业绿色发展水平的提升能够通过正向空间溢出效应带动邻近省份农业绿色转型。（2）创新要素流动存在显著的空间关联特征,R&D人员流动和R&D资本流动均能显著提升地区农业绿色发展水平。（3）R&D人员流动能通过正向空间溢出效应推动邻近省份农业绿色转型,R&D资本流动则会通过负向空间溢出效应阻碍邻近地区农业绿色发展。基于上述研究结论,本文提出相应的对策建议：构建农业绿色技术创新合作网络平台,按要素精准施策,积极完善金融体系和资本市场建设,引导创新要素合理流动。