Productivity Measurement from a Reference Technology: A Distance Function Approach

An approach to productivity measurement based on distance function measurement is developed in this paper. A series of reference technologies are constructed by augmenting observed inputs and outputs such that the resulting effective netputs are consistent with the weak axiom of profit maximization. Geometric means of year-ahead and year-back distance function values serve as measures of multifactor productivity changes. Both primal measures from the inner bound and dual measures from the outer bound of the reference technologies are calculated. Resulting productivity measures are similar to those derived using index number approaches, but potentially provide greater information regarding the reference technologies.     

Weak measurability and characterizations of risk

Summary. In the context of a continuum of random variables, arising, for example, as rates of return in financial markets with a continuum of assets, or as individual responses in games with a continuum of players, an important economic issue is to show how idiosyncratic risk can be removed through some device of aggregation or diversification when such risk is explicitly introduced into the model. In this paper, we use recent work of Al-Najjar [1] as a general backdrop to provide a review of the basic issues involved when the continuum is formulated as the Lebesgue interval. We present two examples to argue that the fundamental problem of the non-measurability of sample functions, originally identified by Doob, and further elaborated by Feldman, Gilles and Judd in the economic literature, simply cannot be bypassed by reinterpretations of standard results. We also provide an equivalence result in the spirit of Al-Najjar's efforts; but argue that this elementary result does not go beyond the standard law of large numbers for a sequence of real-valued iid random variables, and as such, is incapable of yielding anything of substantive economic interest beyond this law. Received: April 23, 1998; revised version: April 28, 1998     

第二类stirling数的又一个恒等式的简化

第二类stirling数是分配问题中的最关键数,当n与r很大时stirling数的计算极为繁琐.给出并证明了当n≥12的第二类stirling数S(n,n-6)的恒等式,从而将n≥8的第二类stirling数S(n,n-4)的计算在文献[1]的基础上向前推进了一步.     

基于熵权法和MADM的电力客户信用风险评价

电力客户的信用风险评价是典型的多属性决策问题,决策者往往很难对每个评价指标赋予一个确定数值,但凭借经验可以给出大致范围。有鉴于此,论文在描述电力客户的各个属性值时采用了区间数的表示形式,并运用熵权法确定出各评价指标的权重,最后计算各个电力客户的综合评价值并进行排序优选。实例研究结果表明这种方法是科学实用的电力客户信用评价比较方法。     

Uncertainty in currency mispricing

Declaring a currency to be mispriced is fraught with uncertainties. In this article, these uncertainties are explicitly recognized in a model of pricing a homogeneous commodity around the world. This allows for a common driver of prices, due to a base-currency effect, and country-specific factors that lead to departures from absolute PPP on account of income differences, local taxes and charges, etc. This approach leads to estimates of currency mispricing whose significance can be tested in the usual way. Using Big Mac prices, we show that the approach has advantages over the popular Big Mac Index to currency valuation.     

大数定律与保险财政稳定性研究

保证保险财政的稳定性,无论对于保险公司自身的发展,还是对于社会的稳定都是非常重要的,因此,对于保险财政稳定性的研究是保险理论研究的重要内容。利用大数定律可以准确地计算出一定条件下为了满足某种精度所需的被保险单位数。     

对数正态分布伪随机数的产生与检验

本文给出了一种产生对数正态分布伪随机数的算法以及相应的检验方法,产生的均匀分布随机序列,经近似抽样产生正态分布的随机数,再经变换抽样最终产生对数正态分布的随机序列。采用卡方检验验证其是否符合对数正态分布。计算实例表明,所给出的方法具有产生伪随机数速度快、数量大、方差小和较长的周期等特点,具有较大的工程实用价值。计算结果验证了所给方法的正确性。     

Comparisons of aggregate claim numbers and amounts: a study of heterogeneity

In this paper, we investigate how the heterogeneity among occurrence probabilities and claim severities affects the aggregate claim numbers and aggregate claim amount for an insurance portfolio. We show that higher heterogeneity (and dependence) among occurrence probabilities results in both smaller aggregate claim numbers and aggregate claim amount in the sense of the mean residual lifetime order. We also prove that as the heterogeneity among the claims increases, the aggregate claim amount increases in the sense of the usual stochastic order when the vector of occurrence probabilities is left tail weakly stochastic arrangement increasing. These theoretical findings are applied to (i) study ordering properties of convolutions of binomial random variables, (ii) provide upper bounds for the mean residual lifetime functions of the aggregate claim numbers and amount, and (iii) compare stop-loss premiums and risk capital of different insurance portfolios.     

基于三角模糊数的服务创新风险分析

在企业或社会中发挥着越来越重要的作用,学者越来越关注对服务的研究,力图通过技术等手段对原有服务进行改造或创新,从而实现效益,但是关于服务创新中风险的研究甚少。因此本文首先利用环境分析法,分析出在服务创新过程中的风险因素,使用基于三角模糊数的模糊层次分析法,对这些风险因素进行评价。最后用一个实例证明这种风险方法,可以更好的进行风险管理,提高服务创新的成功率。