A new bivariate distribution in natural exponential family

We propose a new bivariate distribution following a GLM form i.e., natural exponential family given the constantly correlated covariance matrix. The proposed distribution can represent an independent bivariate gamma distribution as a special case. In order to derive the distribution we utilize an integrating factor method to satisfy the integrability condition of the quasi-score function. The derived distribution becomes a mixture of discrete and absolute continuous distributions. The proposal of our new bivariate distribution will make it possible to develop some bivariate generalized linear models. Further the discrete correlated bivariate distribution will also arise from an independent bivariate Poisson mass function by compounding our proposed distribution (Iwasaki and Tsubaki, 2002).Received March 2003     

VMI模式下最优订货点的仿真研究

通过VMI模式下订货流程的模拟,根据客户订货前置期的历史统计数据或分布函数,利用Arena软件求解配送中心最优订货点。研究表明,仿真分析能获得比常规数学方法更科学合理的最优订货点。     

An improved empirical Bayes test for positive exponential families

We exhibit an empirical Bayes test δ^* _n for a decision problem using a linear error loss in a class of positive exponential families. This empirical Bayes test δ^* _n possesses the asymptotic optimality, and its associated regret converges to zero with rate n ⁻¹(ln n )⁶ This rate of convergence improves the previous results in the literature in the sense that a faster rate of convergence is achieved under much weaker conditions. Examples are presented to illustrate the performance of the empirical Bayes test δ^* _n     

关于韩非法治思想与现代法律的思考

针对先秦儒家的"德治"主张,韩非提出了"法治"理论.韩非的法治思想其实质是君主专制与国家(政府)集权,它与现代法治所倡导的民主与法制精神相悖.但这种"国家(政府)法治"传统却被我们自觉或不自觉地因袭了下来,成为我国经济改革深化和转变政府职能的巨大障碍.为了建立一个好的市场经济,防止滑入一个坏的市场经济,法治应该由国家统治社会和民众的工具变为保护社会和民众的工具,进而成为社会和民众自我保护的工具.法律应该由君主专制的利器变为社会和民众捍卫民主与自由的盾牌.     

工商管理类课程实施案例教学障碍分析与对策

工商管理类课程的传统教学方式以教师为中心,学生处于被动和支配地位。为了丰富课堂气氛、提高教学效果,教学过程有必要寻求一种新的教学方法即案例教学法。正确处理案例教学与理论教学的关系、注意各种案例教学方式的综合运用、丰富案例资源、对学生人数规模加以控制、注意对学生的启发工作、举办有关案例教学的知识讲座是提高案例教学质量水平的关键。     

具有奖励机制与再保险安排的最优保险合约设计

在保险合约中引入奖励机制可以使投保人动态参与到保险合约中,赋予了投保人在面对索赔事件时是否执行索赔的可选择权,改变了传统保险合约中投保人执行索赔的单一权利,但却增加了保险人潜在的流动性风险。保险合约中再保险的安排则可以对冲由于奖励机制产生的潜在流动性风险,进一步分散保险人的风险,有助于保险人稳健经营。基于此,通过建立具有红利奖励机制与再保险安排的最优保险合约设计模型,最终求解得到最优保险合约是具有最优免赔额形式的保险合约。利用算例研究方法进行建模,研究结果显示,最优保险合约中的最优免赔额与奖励机制中的红利奖励之间具有正向关系,保费、自留额与最优免赔额之间则存在着显著的负向关系。     

城市生活垃圾资源化政府最优补贴博弈分析

城市生活垃圾资源化能够带来巨大的经济效益、环境效益与社会效益,是贯彻国家绿色发展理念的必经之路。城市生活垃圾资源化体系的持续发展需要政府补贴作为保障,减少资源化产品与同类非资源化产品的价格差异,弥补相关企业投入产出不匹配的矛盾。本文基于社会福利最大化理论,将政府补贴作为决策变量,构建各利益主体之间的价格博弈模型,确定政府最优补贴额度和其他主体的最优决策,并根据结论提出相关建议。研究表明:要实现整体效益最大化,政府需要在不同环节采取不同的补贴方式与补贴额度。     

Joint Quantity/Quality Management of Groundwater

Economic literature on groundwater managementhas traditionally been split into two areas: there are papers that evaluate different schemes of dynamicaquifer management, considering that pumping costs vary with stock but ignoring water quality. On the other hand, there are papers that considercontamination problems caused by specificpollutants. This paper presents two alternative models for joint quantity-quality management, and it shows that existing models are in fact special cases of these. The framework isdynamic and considers both the stock of waterquantity and a stock measure of water quality. Optimal taxes are derived, and shown to be different from those in existing quantity-only or quality-only models. Implementationproblems are briefly discussed.     

The nature of the steady state in models of optimal growth under uncertainty

Summary. We study a one-sector stochastic optimal growth model with a representative agent. Utility is logarithmic and the production function is of the Cobb-Douglas form with capital exponent . Production is affected by a multiplicative shock taking one of two values with positive probabilities p and 1-p. It is well known that for this economy, optimal paths converge to a unique steady state, which is an invariant distribution. We are concerned with properties of this distribution. By using the theory of Iterated Function Systems, we are able to characterize such a distribution in terms of singularity versus absolute continuity as parameters and p change. We establish mutual singularity of the invariant distributions as p varies between 0 and 1 whenever . More delicate is the case . Singularity with respect to Lebesgue measure also appears for values such that . For and Peres and Solomyak (1998) have shown that the distribution is a.e. absolutely continuous. Characterization of the invariant distribution in the remaining cases is still an open question. The entire analysis is summarized through a bifurcation diagram, drawn in terms of pairs .Received: 9 April 2002, Revised: 29 October 2002, JEL Classification Numbers: C61, O41.Correspondence to: Tapan MitraThis research was partially supported by CNR (Italy) under the "Short-term mobility" program and by M.U.R.S.T. (Italy) National Group on "Nonlinear Dynamics and Stochastic Models in Economics and Finance" . We are indebted to Rabi Bhattacharya for providing us with the reference to Solomyak's (1995) paper. The present version has benefitted from comments by Mukul Majumdar and two anonymous referees.     

退耕还林（草）生态补偿实施现状与问题分析——以甘肃省定西市安定区为例

为了建立合理的国家生态补偿机制，了解现阶段生态补偿中存在的问题，我们运用PRA（Participatory rule appraisal）即参与性农村评估和传统的问卷调查相结合的方法，通过对研究区内生态建设补偿措施实施过程中的现状研究、问题分析，发现本区在实施退耕还林（草）生态补偿中的主要问题是仍然没有有效解决生态补偿的三个基本问题：补偿主体、补偿强度、补偿资金来源。生态补偿处于初级阶段，没有形成制度化、法律化，有必要在政策、法律层面建立比较完善的生态补偿机制。