The probability of degenerate maximum-likelihood estimates with randomly truncated survival data

We study the nonparametric maximum-likelihood estimator of the marginal distribution function in bivariate data with truncated sum (Woodroofe 1985), and calculate the probability that it will assign zero probability to a range of observed values. We show that in a simple artificial model with uniform intensity in both variables the probability may be expressed using recursive formulae, and that large-sample approximations valid under weak regularity conditions show good agreement with as few as 20 observations. In the uniform-intensity model, the probability of degenerate estimates is rather small, being just over 5% with a dataset of 20 observations and falling below 1% with 125 observations. However, in a model of transfusion-associated AIDS in 125 children and adults (Kalbfleisch and Lawless 1989), the probability of degenerate estimates is much larger—about 30% with 20 observations and 3% with the actual 125 observations. This is largely because both the infection and incubation density are increasing over time. Such a pattern makes the condition for degeneracy, i.e., relatively high observed intensity at extreme values of each variable, much more likely.     

作为史家的王瑶与陈寅恪学术路径之交集蠡测

王瑶与陈寅恪不仅有师承关系,而且在学术路径上也交集颇多。总体而言,二者不仅在求是这一学术目的上颇为相合,其实现这一目的的学术路径,诸如＂从史实中求史识＂＂了解之同情＂＂内热的心情＂等,也很是类似。     

A note on positive dependence im multivariate distributioms

I counterexample is presented to the result by Alam and Malleolus asserting that if Y is stochastically increasing in a random vector X, then Y is stochastically increasing in a subvector of X. Their result concerning m*-positive dependence, whose proof relies on the erroneous result, is still true.     

The modified permutation entropy-based independence test of time series

Abstract

In time series, it is essential to check the independence of data by means of a proper method or an appropriate statistical test before any further analysis. Therefore, among different independence tests, a powerful and productive test has been introduced by Matilla-García and Marín via m-dimensional vectorial process, in which the value of the process at time t includes m-histories of the primary process. However, this method causes a dependency for the vectors even when the independence assumption of random variables is considered. Considering this dependency, a modified test is obtained in this article through presenting a new asymptotic distribution based on weighted chi-square random variables. Also, some other alterations to the test have been made via bootstrap method and by controlling the overlap. Compared with the primary test, it is obtained that not only the modified test is more accurate but also, it possesses higher power.     

产品责任与产品质量责任的区别及适用

产品责任与产品质量责任具有不同的法律含义 ,正确认识两者的区别有重要意义。根据我国法律和相关法学理论 ,对产品责任与产品质量责任 ,在性质、构成条件、归责原则、法律程序等方面的区别进行了探讨和分析 ;对健全我国产品责任法规和产品责任管理体系 ,切实实行严格的责任制 ,推广产品责任保险制度等问题提出了观点和建议     

我国客户关系管理研究的紧迫性和方向分析

客户关系管理(CRM ) 是当前的研究热点. 由于国内企业发展的特殊轨迹, 在此方面的研 究和应用明显落后于国外. 针对这种情况, 本文在分析客户关系管理的内涵及其意义的基础 上, 详细阐述了中国加强这一领域研究与应用的重要性和紧迫性, 并探索了国内研究的具体 方向.     

古兰学与经注学关系研究

古兰学(‘Ulūmal-qur’ān)是研究《古兰经》的基础学科,也是伊斯兰文化体系的传统学科。尽管古兰学是一门独立学科,但它因以《古兰经》为研究对象而具有多学科交叉特点,并由此产生了若干分支学科,经注学(‘ilmal-tafsir)则是其中最重要的主干学科。古兰学与经注学在学科原理和认知经文层面的共性关系,既有助于人们了解和理解《古兰经》的文体经义,也为伊斯兰文化发展提供不可或缺的思想资源。     

“幽灵性”范畴与逻辑及其后马克思取向

幽灵性是德里达早期以异延为中轴的解构理路的继承与发展;它与＂无X的X＂、弥赛亚性、宗教性等话语筑起解构的马克思主义逻辑场域。幽灵性抛弃了历史唯物主义的分析范式和基础——主导辩证法,解构了马克思主义的阶级解放政治学,成为对德里达解构的马克思主义进行后马克思思潮认知测绘的关键依据。     

山西省生态旅游农业模式初探

目前生态旅游农业是农业和旅游业结合起来的一种新型旅游方式,在旅游业中占有重要的地位。而山西省是一个具有悠久农业历史的农业省份,丰富的农业资源又为生态旅游农业的发展提供了良好的基础。从山西省的实际资源出发,分析了山西省生态旅游农业可选择休闲观光农场、森林旅游、民俗旅游和一些融合了新农村建设的发展模式,这些模式将有利于促进农村生态资源优势转变、扩大就业,最终推动现代农业发展。试图通过采取政府支持、农民参与和以市场为导向这些措施,加速山西省生态旅游农业发展,为山西农业、旅游业发展创造新契机。     

肇庆地区男子1500m运动员专项素质结构特征分析

运用文献资料法、调查法、训练实验和数理统计法,对肇庆学院及肇庆市体校12名男子1 500 m运动员的15项专项素质指标进行了测试,应用＂旋转后的因子载荷矩阵＂统计方法进行分析,揭示了影响肇庆地区男子1 500 m运动员专项成绩提高的专项素质结构性要素,其主导因素为速度耐力、速度、下肢爆发力和一般耐力,典型指标为2 000 m、5 000 m、400 m、600 m跨步跳.