Multiple event times in the presence of informative censoring: modeling and analysis by copulas

Motivated by a breast cancer research program, this paper is concerned with the joint survivor function of multiple event times when their observations are subject to informative censoring caused by a terminating event. We formulate the correlation of the multiple event times together with the time to the terminating event by an Archimedean copula to account for the informative censoring. Adapting the widely used two-stage procedure under a copula model, we propose an easy-to-implement pseudo-likelihood based procedure for estimating the model parameters. The approach yields a new estimator for the marginal distribution of a single event time with semicompeting-risks data. We conduct both asymptotics and simulation studies to examine the proposed approach in consistency, efficiency, and robustness. Data from the breast cancer program are employed to illustrate this research.

     

External knowledge search,absorptive capacity and radical innovation in high-technology firms

Open innovation and absorptive capacity are two concepts based on the idea that companies can leverage the knowledge generated externally to improve their innovation performance. The aim of this paper is to analyse the joint effect of open innovation and absorptive capacity on a firm's radical innovation. Open innovation is expressed in terms of external search breadth and depth strategies and absorptive capacity is described by distinguishing between potential and realized absorptive capacity. In order to test our hypotheses, we carried out empirical research in firms operating in high-technology industries. The results indicate that internal routines and processes for absorbing external knowledge help explain radical innovation as they show a significant effect of potential and realized absorptive capacity. Also, there is a moderating effect of absorptive capacity on open innovation. Specifically, potential absorptive capacity exerts a positive effect on the relationship between external search breadth and depth and radical innovation. Realized absorptive capacity moderates the influence of external search breadth. These findings confirm the complementary nature of absorptive capacity and open innovation search strategies on radical innovation.     

我国实行村民自治制度必然性的经济分析

村民自治制度作为我国农村民主制度建设的主体 ,在实践中显示出了强大的活力和蓬勃的生机。村民自治制度形成的原因很多 ,本文运用经济分析的方法 ,在成本—收益理论的框架下 ,从政府、村民、村民自治制度三个不同的层面出发 ,揭示出了实行村民自治制度必然性的经济上的原因     

论观点采择与皮亚杰的去自我中心化

关于儿童对个人的心理过程、心理特征的认知的研究始于皮亚杰。皮亚杰提出了“自我中心化”和“去自我中心化”的概念 ,在社会认知发展的研究中占有重要的地位。观点采择的本质特征在于个体认识上的去自我中心化 ,即能够站在他人的角度 ,从他人的角度看待问题。对观点采择的研究是对皮亚杰关于儿童自我中心化和去自我中心化发展研究的继承和发展     

用Excel统计数值型数据频数分布的三种方法

本文根据两种不同的数据分组方式,分别讨论了利用Excel软件统计数值型数据频数分布的三种基本方法并作了简要评述。     

R12在水平管内流动沸腾换热实验研究

本文对R12在水平管内流动沸腾换热特性作了实验研究。实验结果表明,管内流动沸腾换热与单相对流换热一样,存在热进口效应,国外早期的实验数据由于未能考虑热进口效应而偏大。实验结果还表明,水平流动沸腾周向不均匀换热主要受流动结构影响;截面平均换热系数则与质量流速、热流密度、质量干度和蒸发压力密切相关。分析实验数据证实,流动沸腾换热是由气泡产生而引起的流动充分发展核态沸腾和双相对流蒸发两部分组成的。本文的实验数据与国外已有的换热关系式能较好吻合。     

优选方案定量评价模型研究

在确定评价指标体系的基础上，如何对若干事物或方案进行选优是一个十分有意义的问题．作者利用模糊多目标决策对此进行研究，并通过实例说明该方法的有效性与实用性．     

Marginal and association regression models for longitudinal binary data with drop‐outs: A likelihood‐based approach

Longitudinal data often contain missing observations, and it is in general difficult to justify particular missing data mechanisms, whether random or not, that may be hard to distinguish. The authors describe a likelihood‐based approach to estimating both the mean response and association parameters for longitudinal binary data with drop‐outs. They specify marginal and dependence structures as regression models which link the responses to the covariates. They illustrate their approach using a data set from the Waterloo Smoking Prevention Project They also report the results of simulation studies carried out to assess the performance of their technique under various circumstances.     

企业发展论研究

在分析企业经济控制论系统的特征及其基本结构的基础上,提出企业经济控制系统调节控制的基本公式,阐述了企业经济系统的控制转换模型,最终提出企业发展要研究的主要问题包括企业经济系统理论研究、企业投入要素研究、企业发展经营运行研究等。