Growth and social capital: an evolutionary model

In this paper, we analyze the role of cooperation between firms through a model of growth and social capital. In a growth model à la Solow we incorporate the set of resources that a relational network has at its disposals, as a distinct production factor, and thus examine its dissemination through evolutionary type processes in firm interactions. Dynamic analysis of the model demonstrates that cooperation is able to increase the productivity of factors, fostering a higher rate of growth in the long term. The most significant result is that scarcity of social capital can produce a general collapse of the economic system in areas in which long term growth is usually sustained by the learning by doing and spillover of knowledge phenomena. This conclusion leads to reconsider the role of local development economic policies that should concentrate on activities that promote repeated interaction between firms proven to be cooperative or that encourage the formation of technological consortia.     

FPS故障定位系统的探索

小电流单相接地故障在线定位一直是制约供电企业提高供电质量的关键问题之一。通过对接地系统单相接地故障进行分析,提出一种综合了小电流选线装置和故障指示器二者优点的故障定位系统FPS,应用小电流接地选线中比较准确的接地判据(群体比幅比相和稳态零序电流的综合),利用故障指示器缩小故障区域,从而准确定位故障。该系统既能准确判断故障,又能缩小故障区域以缩短巡线和排除故障时间。     

“Relative Importance of Risk Sources in Insurance Systems”, Edward W. Frees,April 1998

Abstract

This paper considers a Sparre Andersen collective risk model in which the distribution of the interclaim time is that of a sum of n independent exponential random variables; thus, the Erlang(n) model is a special case. The analysis is focused on the function φ(u), the expected discounted penalty at ruin, with u being the initial surplus. The penalty may depend on the deficit at ruin and possibly also on the surplus immediately before ruin. It is shown that the function φ(u) satisfies a certain integro-differential equation and that this equation can be solved in terms of Laplace transforms, extending a result found in Lin (2003). As a consequence, a closed-form expression is obtained for the discounted joint probability density of the deficit at ruin and the surplus just before ruin, if the initial surplus is zero. For this formula and other results, the roots of Lundberg’s fundamental equation in the right half of the complex plane play a central role. Also, it is shown that φ(u) satisfies Li’s (2003) renewal equation. Under the assumption that the penalty depends only on the deficit at ruin and that the individual claim amount density is a combination of exponential densities, a closed-form expression for φ(u) is derived. In this context, known results of the Cauchy matrix are useful. Surprisingly, certain results are best expressed in terms of divided differences, a topic deleted from the actuarial examinations at the end of last century.     

基于最优配送路线的选址方法研究

分析物流配送中心在运输方面的特点和优点,指出传统选址决策方法忽视配送中心运输方式优势的发挥,无法最大限度降低物流成本.在此基础上提出基于最优配送路线的选址方法,以降低综合物流成本.     

新制度经济学视野下的城市群协调发展探讨

城市群现象是城市区域化、区域城市化的结果，更是政治、资本、技术、制度和自然资源多者共同选择、作用的结果。城市化史表明，这种现象只有在那些具有良好区位和自然社会经济条件的地区才能出现。城市群地区形成后，由于具有优良的基础设施、易于形成城市规模效益和范围经济，从而成为企业布局、人口迁移的主要选择，成为国家社会经济发展的支柱。但同时，由于众多城市在一定地域内集聚发展，也会加剧城市之间的竞争，带来对资源、市场的争夺，城市之间的摩擦、冲突会加剧，导致不协调发展现象。     

传统体育在养生中的独特作用

运用传统中医学与保健理论,结合体育运动原理,对我国传统体育养生思想进行了研究,分析总结了传统体育在养生中的独特作用,提高我们对传统体育的养生功效的进一步认识和在全民健身中的运用。     

An alternative procedure for imputing missing data based on principal components analysis

This work entailed tackling the significant problem of missing data which was solved by identifying a new substitution procedure, following an empirical approach based on the analysis of the information contained in the entire set of data collected. This procedures offers a number of advantages compared to other techniques commonly mentioned in the statistical–methodological literature.     

CO_2硬化碱性酚醛树脂交联剂的研究

本文重点对树脂砂交联剂的类型和加入量进行了系统深入的研究。在实验中,以试样抗压强度为主要考察目标,考察了氢氧化钾、硅烷、硼砂加入量对试样抗压强度的影响,获得了交联剂加入量的最佳配比,制成了可用于生产的粘结剂。