SUFFICIENT CONDITIONS FOR A GEOMETRIC TAIL IN A QBD PROCESS WITH MANY COUNTABLE LEVELS AND PHASES

Abstract

In this paper, we present sufficient conditions, under which the stationary probability vector of a QBD process with both infinite levels and phases decays geometrically, characterized by the convergence norm η and the 1/η-left-invariant vector x of the rate matrix R. We also present a method to compute η and x based on spectral properties of the censored matrix of a matrix function constructed with the repeating blocks of the transition matrix of the QBD process. What makes this method attractive is its simplicity; finding η reduces to determining the zeros of a polynomial. We demonstrate the application of our method through a few interesting examples.     

Polynomial Factorization for Servers with Semi-Markovian Workload: Performance and Numerical Aspects of a Verified Solution Technique

Abstract

We investigate polynomial factorization as a classical analysis method for servers with semi-Markov arrival and service processes. The modeling approach is directly applicable to queueing systems and servers in production lines and telecommunication networks, where the flexibility in adaptation to autocorrelated processes is essential.

Although the method offers a compact form of the solution with favourable computation time complexity enabling to consider large state spaces and system equations of high degree, numerical stability is not guaranteed for this approach. Therefore we apply interval arithmetic in order to get verified results for the workload distributions, or otherwise to indicate that the precision of the computation has to be improved. The paper gives an overview of numerical and performance aspects of factorization in comparison to alternative methods.     

Estimation and Welfare Analysis With Large Demand Systems

We develop an approach for estimating individual or household level preferences for a large set of quality-differentiated goods and for constructing Hicksian welfare measures within the demand system framework. Our approach uses a maximum simulated likelihood procedure to recover estimates of the structural parameters and a multistage, Monte Carlo Markov chain algorithm for constructing Hicksian consumer surplus estimates. We illustrate our approach with a recreation dataset consisting of day trips to 62 Mid-Atlantic beaches.     

A natural conjugate prior for the nonhomogeneous poisson process with an exponential intensity function

This article presents a natural conjugate prior for the nonhomogeneous Poisson process (NHPP) with an exponential intensity function, for modeling the failure rate of repairable systems. The behavior of the conjugate prior distribution with respect to its parameters is studied, and the use of this prior in Bayesian estimation is compared to two other estimation approaches (the use of independent prior distributions, and the bivariate normal distribution). The use of the conjugate prior proposed here facilitates Bayesian statistical analysis of aging. In particular, the proposed prior allows us to explicitly account for dependence between the initial failure rate and the aging rate. This is a significant improvement over the assumptions made in most prior work (either the assumption that the aging rate is known, or the assumption that the initial failure rate and the aging rate are independent). Monte Carlo simulation shows that Bayesian estimation using the proposed prior generally performs at least as well as Bayesian estimation using independent priors for the initial failure rate and the aging rate,except in the case where the prior distribution underestimates both the initial failure rate and the aging rate.     

青岛一套表的实践与经验

 企业统计一套表一直是统计制度方法改革和实践中的焦点问题。本文通过对青岛市统计局企业一套表制度实施情况的案例分析,系统界定了企业一套表的概念和内涵,全面展现了企业一套表的运作过程,客观分析了制约企业一套表实施的主要原因,并提出了在现阶段实施企业统计一套表的条件和要求。     

中国农村公共服务评价体系研究

农村公共服务水平低下和不平衡是导致城乡差距日益扩大的重要影响因素之一。本文试图构建农村公共服务发展状况评价指标体系,并基于2006年的数据进行实证研究,给出了研究结果的进一步分析评价。     

能级稳态结构──对政府体制优化的一种思考

传统行政管理理论关于能级对应原理中的能级稳态结构模式唯正三角形结构的观点失之偏颇。事实上,政府体制的能级稳态结构不是教条式的,它因历史—社会—文化条件的不同而不同;政府体制的能级稳态结构不是僵化、一成不变的,它随历史—社会—文化条件的发展而发展。当代中国政府体制经过历次变迁正走向一条渐进、理性的道路,在保持“中国特色”政府体制稳态结构──正三角形结构的基本架构不变的基础上,随着历史—文化—社会条件的变化而不断作出调整和优化,这是一条走向全面现代化的成功之路。     

大中型企业构建物资供应管理体系的对策

物资供应管理既是一个技术过程,也是一个管理过程.构建完善的物资供应管理体系,使物资供应管理工作达到效益和效率双项目标的统一,是大中型企业的当务之急.     

试论离婚之精神损害赔偿制度

离婚之精神损害有离因精神损害和离婚精神损害两种.前者是夫妻一方对另一方构成侵权行为而导致离婚,从而给一方造成精神痛苦,受害方可请求精神损害赔偿.我国新的<婚姻法>确立了这一精神损害赔偿制度,填补了我国婚姻制度的一个空缺.而后者是夫妻一方对另一方并无侵权行为,离婚本身即为构成精神损害之直接原因,如由于第三者插足、婚外恋、夫妻一方被判处徒刑等.这种离婚同样使一方受到精神损害,自然也应得精神损害赔偿.遗憾的是,新的<婚姻法>并未作此规定.因此,要完善我国离婚之精神损害赔偿制度,不仅要使离婚之精神损失赔偿的权利义务主体进一步扩大,把第三者也作为离婚之精神损害赔偿的义务主体,而且还要将离因精神损害赔偿扩大到离婚精神损害赔偿,将因婚外恋、第三者插足、因配偶一方犯罪而被判入狱和其他原因导致离婚的情况作出规定,使精神受害者得到应有的经济救济和补偿.     

“创造美学“面向未来的开放体系——蒋孔阳先生美学思想特色初探

"创造美学"是蒋孔阳先生建构的美学思想体系和美学学派.蒋孔阳美学体系所以卓然自成一家,就在于它的对于美与实践、美与创造、美与艺术和人与现实的审美关系的独到的阐述和极具建树的概括,及其包容性、创造性、开放性的特点.蒋孔阳创造性地把"实践美学"推进、发展、延伸到"创造美学",拓展、丰富了"创造"概念在美学中的内涵,是对于中国当代美学研究的历史进程、研究现状、未来发展的思考性总结,也是对于中国当代美学的卓越贡献.