The Method to Identify a Biomarker and to Evaluate Its Efficiency for Survival by Using the Joint Model of the Accelerate Failure Time and Longitudinal Data

In this article, we discuss how to identify longitudinal biomarkers in survival analysis under the accelerated failure time model and also discuss the effectiveness of biomarkers under the accelerated failure time model. Two methods proposed by Shcemper et al. are deployed to measure the efficacy of biomarkers. We use simulations to explore how the factors can influence the power of a score test to detect the association of a longitudinal biomarker and the survival time. These factors include the functional form of the random effects from the longitudinal biomarkers, in the different number of individuals, and time points per individual. The simulations are used to explore how the number of individuals, the number of time points per individual influence the effectiveness of the biomarker to predict survival at the given endpoint under the accelerated failure time model. We illustrate our methods using a prothrombin index as a predictor of survival in liver cirrhosis patients.     

The inner circle: Building bridges or boundaries between researchers and practitioners

An epistemological and methodological approach, The Change Laboratory, is analysed to determine which forms of distributing knowledge are apparent during cross-cultural research. Distributing knowledge is intricately related to methodological design, to researchers’ and practitioners’ life experiences and to roles of power. The article concludes that research conducted across cultures necessitates careful analysis of the power found within forms of distributing knowledge. This power is derived from a tacit belief that certain knowledge is only available to those within a given circle or that it is available to those outside a given circle without alteration.     

Nonparametric density deconvolution by weighted kernel estimators

Nonparametric density estimation in the presence of measurement error is considered. The usual kernel deconvolution estimator seeks to account for the contamination in the data by employing a modified kernel. In this paper a new approach based on a weighted kernel density estimator is proposed. Theoretical motivation is provided by the existence of a weight vector that perfectly counteracts the bias in density estimation without generating an excessive increase in variance. In practice a data driven method of weight selection is required. Our strategy is to minimize the discrepancy between a standard kernel estimate from the contaminated data on the one hand, and the convolution of the weighted deconvolution estimate with the measurement error density on the other hand. We consider a direct implementation of this approach, in which the weights are optimized subject to sum and non-negativity constraints, and a regularized version in which the objective function includes a ridge-type penalty. Numerical tests suggest that the weighted kernel estimation can lead to tangible improvements in performance over the usual kernel deconvolution estimator. Furthermore, weighted kernel estimates are free from the problem of negative estimation in the tails that can occur when using modified kernels. The weighted kernel approach generalizes to the case of multivariate deconvolution density estimation in a very straightforward manner.     

戏曲艺术：不断地探寻新形式——戏剧反思录之二

任何一种文化现象都表现为一个历史过程，都具有鲜明的时代性。戏曲艺术形式达到高峰之后，常常会在自己内部孕育着异己的胚胎，导致发生逆向的转折。在戏曲艺术世界中，可以说一直就是处在这种艺术形式变革的探索之中。     

Measurement error, skewness, and risk analysis: coping with the long tail of the distribution.

Probabilistic risk analyses often construct multistage chance trees to estimate the joint probability of compound events. If random measurement error is associated with some or all of the estimates, we show that resulting estimates of joint probability may be highly skewed. Joint probability estimates based on the analysis of multistage chance trees are more likely than not to be below the true probability of adverse events, but will sometimes substantially overestimate them. In contexts such as insurance markets for environmental risks, skewed distributions of risk estimates amplify the "winner's curse" so that the estimated risk premium for low-probability events is likely to be lower than the normative value. Skewness may result even in unbiased estimators of expected value from simple lotteries, if measurement error is associated with both the probability and pay-off terms. Further, skewness may occur even if the error associated with these two estimates is symmetrically distributed. Under certain circumstances, skewed estimates of expected value may result in risk-neutral decisionmakers exhibiting a tendency to choose a certainty equivalent over a lottery of equal expected value, or vice versa. We show that when distributions of estimates of expected value are, positively skewed, under certain circumstances it will be optimal to choose lotteries with nominal values lower than the value of apparently superior certainty equivalents. Extending the previous work of Goodman (1960), we provide an exact formula for the skewness of products.     

张学良主政东北时的反日行动

张学良主政东北期间,国难家仇系于一身,反日思想极为浓烈,先后在东北推行了一系列反日政策,并付诸实施。如摆脱日本羁绊毅然“易帜”;推行“Q型计划”包围满铁;实施反日教育等等。     

基于资源观的企业IT能力理论及实证研究

本文研究目的是探讨企业IT能力的构成、测量及其提升问题.基于我国信息化实践背景,以企业资源观(Resource-based View)为理论依据,提出IT能力构成维度的概念模型,设计问卷及测量问题,并进行了数据收集以及信度、效度检验等实证研究对理论模型予以验证.最后,根据数据分析结果,为企业建立IT能力给出一系列的指导建议,从而有助于通过IT应用获取竞争优势.     

A decomposition technique for quantifying real process performance

A decomposition technique for quantifying the impacts of changes in product mix and process performance on aggregate process-related indicators is presented. Through application of the technique, the real performance of a process can be quantified. Changes in real performance over time can be monitored to provide useful information for process evaluation and production planning. Two case studies, one related to the aggregate defective rate for an assembly line of an integrated circuit fabrication plant and the other to the aggregate inventory turnover for a tyre distribution company, are presented to illustrate the application of the technique.     

Integrated enterprise modelling: A method for the management of change

'The capability to adjust to new conditions quickly has developed into a decisive competitive advantage. You cannot waste any time if you want to be successful.' (Emeritus Professor Dr h. c. mult. Changing conditions in the market place issue new challenges to small- and medium-sized enterprises. Organization and qualification of employees have to be adjusted to the modified situation. If the only steady factor is change, the management of change is going to be the outstanding role of the leader. The successful structuring of change processes requires powerful methods and tools: to make business processes transparent and lean; to find a common 'corporate language' based upon customers benefits and shareholders value; Dr-Ing. G. Spur) to bring together process know-how in a central information base. This contribution summarizes the experiences from several projects. We will show how the synchronization of necessary reengineering measures makes corporate knowledge active, e.g. to improve the shareholders value, reduce investment costs, and shorten the duration of projects. As successful examples two medium-sized companies are described.