Some ordering properties of series and parallel systems with dependent component lifetimes

Abstract

In this paper, we consider series systems and parallel systems with the dependence between the component lifetimes modelled by an Archimedean copulas. We obtain sufficient and necessary conditions of relative ageing orders between series (parallel) systems with different component numbers, which partially generalize some main results of Misra and Francis. When the component lifetimes follow the scale model, we also characterize the ordering properties between the series systems and (n–1)-out-of-n systems (parallel systems and 2-out-of-n systems) by mixture distribution.     

中国城镇化质量研究

 中国城镇化进程,特别是中华人民共和国建国以来曲折的城镇化进程给中国几代人留下了深刻的印象。本文对以往研究进行了综述,建立了中国城镇化质量评价指标体系,并对全国及31个地区的城镇化质量进行了评价分析。     

Penalized least-squares estimation for regression coefficients in high-dimensional partially linear models

We consider a partially linear model with diverging number of groups of parameters in the parametric component. The variable selection and estimation of regression coefficients are achieved simultaneously by using the suitable penalty function for covariates in the parametric component. An MM-type algorithm for estimating parameters without inverting a high-dimensional matrix is proposed. The consistency and sparsity of penalized least-squares estimators of regression coefficients are discussed under the setting of some nonzero regression coefficients with very small values. It is found that the root p_n/n-consistency and sparsity of the penalized least-squares estimators of regression coefficients cannot be given consideration simultaneously when the number of nonzero regression coefficients with very small values is unknown, where p_n and n, respectively, denote the number of regression coefficients and sample size. The finite sample behaviors of penalized least-squares estimators of regression coefficients and the performance of the proposed algorithm are studied by simulation studies and a real data example.     

Analytical and numerical studies on the second-order asymptotic expansion method for European option pricing under two-factor stochastic volatilities

The celebrated Black–Scholes model made the assumption of constant volatility but empirical studies on implied volatility and asset dynamics motivated the use of stochastic volatilities. Christoffersen in 2009 showed that multi-factor stochastic volatilities models capture the asset dynamics more realistically. Fouque in 2012 used it to price European options. In 2013, Chiarella and Ziveyi considered Christoffersen’s ideas and introduced an asset dynamics where the two volatilities of the Heston type act separately and independently on the asset price, and using Fourier transform for the asset price process and double Laplace transform for the two volatilities processes, solved a pricing problem for American options. This paper considers the Chiarella and Ziveyi model and parameterizes it so that the volatilities revert to the long-run-mean with reversion rates that mimic fast (for example daily) and slow (for example seasonal) random effects. Applying asymptotic expansion method presented by Fouque in 2012, we make an extensive and detailed derivation of the approximation prices for European options. We also present numerical studies on the behavior and accuracy of our first- and second-order asymptotic expansion formulas.     

浅谈财务风险的成因及防范措施

财务风险是客观存在的。本文在分析财务风险成因的基础上,有针对性地提出了 一些防范措施。     

对当前国际形势问题的几点思考

"三个代表"重要思想是在新世纪把握国际形势变动和确定中国外交战略的指导思想,关键在于坚持与时俱进.在判断当前国际形势走向上,坚持与时俱进具体体现在把握以世界多极化、经济全球化、国际关系民主化和发展模式多样化为主要内容的科学时代观.国际形势正在发生复杂的变化,但和平与发展仍然是当前世界的两大主题,地区冲突仍将是国际斗争的主要形式.对于中国来说,当前的主要任务是正确处理反恐与反霸的关系,特别是紧紧抓住战略机遇期,为中国全面建设小康社会和推动社会主义现代化建设进程创造良好的国际环境.     

生物发光分析

本文评述了国内外生物发光分析的现状及其在生物医学、生命科学、临床化学与检验及免疫学等方面的应用.     

美国人的世界使命感与冷战的起源

“世界使命意识”是美国外交思想中的一个重要因素 ,它根深蒂固于美国的历史和文化之中 ,成为美国对外扩张谋取霸权的招牌。第二次世界大战结束以后 ,美国登上了资本主义世界霸主的宝座。客观条件的具备使美国领导人脑海中的“世界使命意识”随之增强 ,它与美国争夺世界霸权的企图相结合 ,加速了冷战的到来     

“分享制”是促进企业持续创新的最佳分配模式

"分享制"的本质表现为人力资本的所有者参与剩余分配.企业创新要求实施"分享制","分享制"能更好地促进企业的持续创新,二者相辅相成.实施"分享制"要因企制宜、因时制宜、因人而异,"分享制"只是企业实现持续创新的必要条件之一,实施"分享制"不能唯"分享制".     

基于巢式Logit模型的城市轨道交通客流分配问题研究

传统的城市轨道交通网络客流分配方法使用了基于离散选择理论的多项Logit模型,与其相比,巢式Logit模型消除了影响因素的相关性,具有更好的解释能力。介绍了巢式Logit模型的原理及公式,以城市轨道交通网络中乘客的出行行为为研究对象,将乘客选择过程分为换乘次数选择和换乘路径选择两个层次,并以此为构架建立了城市轨道交通客流分配巢式Logit模型。通过实例,利用SAS软件对模型进行求解和分析,从概率角度用定量方法分析出行个体的出行选择行为和轨道交通网络流量分配,对于提高城市轨道交通网络化运营组织水平、进行合理的运能配置和构建城市轨道交通票务清分系统意义重大。