Product-limit Estimators and Cox Regression with Missing Censoring Information

The Kaplan–Meier estimator of a survival function requires that the censoring indicator is always observed. A method of survival function estimation is developed when the censoring indicators are missing completely at random (MCAR). The resulting estimator is a smooth functional of the Nelson–Aalen estimators of certain cumulative transition intensities. The asymptotic properties of this estimator are derived. A simulation study shows that the proposed estimator has greater efficiency than competing MCAR-based estimators. The approach is extended to the Cox model setting for the estimation of a conditional survival function given a covariate.     

电信发展趋势与运营转型

在经历了10多年的高速发展之后，中国电信运营企业已经进入业务与产品运营阶段。因此，电信运营企业应通过整合内外资源，科学构建业务网络，合理进行组织变革，并通过成功的产品管理，利用业务平台提供满足客户个性化需求的产品，实现电信运营企业的成功转型，最终保证企业的长期盈利能力。     

过程创新和产品创新的市场竞争程度分析——基于我国工业企业的实证研究

文章首先利用多个指标估算了在我国工业的37个行业的过程创新和产品创新的水平,然后依据市场竞争程度把这些行业归为三类,从而分析竞争程度对过程创新和产品创新的影响,在此基础上,提出了适度竞争最有利于过程创新和产品创新的结论。     

Double Sampling Ratio-product Estimator of a Finite Population Mean in Sample Surveys

It is well known that two-phase (or double) sampling is of significant use in practice when the population parameter(s) (say, population mean X¯) of the auxiliary variate x is not known. Keeping this in view, we have suggested a class of ratio-product estimators in two-phase sampling with its properties. The asymptotically optimum estimators (AOEs) in the class are identified in two different cases with their variances. Conditions for the proposed estimator to be more efficient than the two-phase sampling ratio, product and mean per unit estimator are investigated. Comparison with single phase sampling is also discussed. An empirical study is carried out to demonstrate the efficiency of the suggested estimator over conventional estimators.     

透过精神产品看艺术市场

精神产品是一种社会产品，其核心是精神内容，其功用是为了满足购买者精神上的需求和享受。随着社会经济的不断发展，精神消费在人们日常总消费中占据越来越重要的位置，精神产品消费的可替代性日益减小，精神产品的消费需求张力急剧增大。艺术市场成为衡量精神产品价值量的经济杠杆，也为精神产品实现其价值提供了可能，具有广阔的经济前景。     

陕西农村经济增长视角的农村信贷产品创新研究

运用1998—2009年陕西省农村信贷产品相关数据,就农村信贷产品对农村经济发展的贡献进行了实证分析,发现农村信贷产品和农村经济发展之间存在显著的正相关关系,农村信贷产品的发展是农村经济发展的原因之一。并针对当前农村信贷产品存在的问题和农户的需求,对陕西农村信贷产品创新进行了研究,其目的是在实现"三农"公平享受金融资源的基础上,促进陕西农村经济快速增长。     

关于我国林产品安全问题的思考

产品安全问题是我国经济领域的热点问题。本文讨论了林产品安全的概念与内涵，认为林产品安全既包括质量安全又包括生态安全。在此基础上，文章论述了当前我国林产品质量安全与生态安全的现状及发展动向。最后，文章得出了我国林产品总体上尚处于不安全状态的初步结论。     

有期权条件下的易逝品订购策略研究

在现实生活中,有大量的易逝品存在.由于易逝品价值递减的特性和需求的不确定性,使易逝品的订购较为困难并可能在期末由于未能出售导致零售商蒙受巨大的损失.作者将期权引入了易逝品订购之中,以最大化期望收益为目标,给出了易逝品最优订购数量.     

白字戏来源研究概述——兼谈剧种研究之方法

潮剧与白字戏历史上是同一个剧种,都叫做白字戏,鉴于白字戏来源问题的众说纷纭及诸多疑惑,在研究剧种的形成时一定要从构成剧种的基本要素——演出主体、戏剧产品及戏剧受众三方面综合审视,孤立地看待研究对象则难免片面。基于此,乡社祭祀赛会是白字戏生存发展的温床,而外来剧种是其由小戏成熟为地方剧种的催化剂,地方小戏与外来剧种都是形成白字戏的不可或缺的两大要素。     

Identifying Dispersion Effects in Robust Design Experiments—Issues and Improvements

The two experimental methods most commonly used for reducing the effect of noise factors on a response of interest Y aim either to estimate a model of the variability (V(Y), or an associated function), that is transmitted by the noise factors, or to estimate a model of the ratio between the response (Y) and all the control and noise factors involved therein. Both methods aim to determine which control factor conditions minimise the noise factors' effect on the response of interest, and a series of analytical guidelines are established to reach this end. Product array designs allow robustness problems to be solved in both ways, but require a large number of experiments. Thus, practitioners tend to choose more economical designs that only allow them to model the surface response for Y. The general assumption is that both methods would lead to similar conclusions. In this article we present a case that utilises a design based on a product design and for which the conclusions yielded by the two analytical methods are quite different. This example casts doubt on the guidelines that experimental practice follows when using either of the two methods. Based on this example, we show the causes behind these discrepancies and we propose a number of guidelines to help researchers in the design and interpretation of robustness problems when using either of the two methods.