我国企业多元化投资决策的反思

企业多元化经营战备是当今世界许多大中型企业的一种战备选择。我国的一些大企业近年来也走上了多元化经营的道路 ,但多数都身陷困境或遭受失败 ,主要是由于多元化投资决策失误所致。因此 ,深入探讨多元化投资的理论和战略 ,对我国一些大中型企业来说 ,就显得十分重要。     

"职业教育"概念与功能的历史观

职业伴随着劳动分工而产生,职业教育则是近代大机器工业的产物。在不同的历史时期,人们从不同的角度观察,并对职业教育产生了不同的认识,以不同的名称表述,赋予不同的功能。"五四"时期职业教育的多元共生,反映出人们对职业教育概念、功能的不同认识,这也是中国近代职业教育向现代职业教育跨越的重要标志。     

Bayesian Estimation of Survival Functions under Stochastic Precedence

When estimating the distributions of two random variables, X and Y, investigators often have prior information that Y tends to be bigger than X. To formalize this prior belief, one could potentially assume stochastic ordering between X and Y, which implies Pr(X < or = z) > or = Pr(Y < or = z) for all z in the domain of X and Y. Stochastic ordering is quite restrictive, though, and this article focuses instead on Bayesian estimation of the distribution functions of X and Y under the weaker stochastic precedence constraint, Pr(X < or = Y) > or = 0.5. We consider the case where both X and Y are categorical variables with common support and develop a Gibbs sampling algorithm for posterior computation. The method is then generalized to the case where X and Y are survival times. The proposed approach is illustrated using data on survival after tumor removal for patients with malignant melanoma.     

Marginal Means/Rates Models for Multiple Type Recurrent Event Data

Recurrent events are frequently observed in biomedical studies, and often more than one type of event is of interest. Follow-up time may be censored due to loss to follow-up or administrative censoring. We propose a class of semi-parametric marginal means/rates models, with a general relative risk form, for assessing the effect of covariates on the censored event processes of interest. We formulate estimating equations for the model parameters, and examine asymptotic properties of the parameter estimators. Finite sample properties of the regression coefficients are examined through simulations. The proposed methods are applied to a retrospective cohort study of risk factors for preschool asthma.     

Regression Analysis of Restricted Mean Survival Time Based on Pseudo-Observations

Regression models for survival data are often specified from the hazard function while classical regression analysis of quantitative outcomes focuses on the mean value (possibly after suitable transformations). Methods for regression analysis of mean survival time and the related quantity, the restricted mean survival time, are reviewed and compared to a method based on pseudo-observations. Both Monte Carlo simulations and two real data sets are studied. It is concluded that while existing methods may be superior for analysis of the mean, pseudo-observations seem well suited when the restricted mean is studied.     

茅盾小说与"红楼"情结

“红楼”情结是茅盾经久的“图像仓库”的土壤。但这种情结不是板块式地嵌入的 ,而是经由转化、挪移、重组化合而生成的。这种历史的承传 ,可以是正面的 ,也可以是负面的。同时 ,这种对民族文化的吸取是在与中外艺术的多元交糅的关系中 ,融通建构的。     

克里斯特瓦的理论背景与诗学思想

克里斯特瓦是当代法国著名的文学理论家和批评家,她的诗学思想融合了多种学科的知识,且复杂多变。她既受马克思、阿尔都塞、黑格尔、索绪尔、巴赫金、弗洛伊德、拉康、德里达、巴特等人的影响,又修正、发展或批判他们的理论。她创建的解析符号学和互文性理论促进了后结构主义理论的发展;她对文本的对话论、复调结构以及诗性话语的探讨,丰富和发展了巴赫金的文学理论;她关于女性与女性特质的界定,使她的女性主义诗学独树一帜;她对欲望、母性、爱情、卑贱等主题的探讨,修正了传统的精神分析方法。     

Estimation of a Change Point in a Hazard Function Based on Censored Data

The hazard function plays an important role in reliability or survival studies since it describes the instantaneous risk of failure of items at a time point, given that they have not failed before. In some real life applications, abrupt changes in the hazard function are observed due to overhauls, major operations or specific maintenance activities. In such situations it is of interest to detect the location where such a change occurs and estimate the size of the change. In this paper we consider the problem of estimating a single change point in a piecewise constant hazard function when the observed variables are subject to random censoring. We suggest an estimation procedure that is based on certain structural properties and on least squares ideas. A simulation study is carried out to compare the performance of this estimator with two estimators available in the literature: an estimator based on a functional of the Nelson-Aalen estimator and a maximum likelihood estimator. The proposed least squares estimator tums out to be less biased than the other two estimators, but has a larger variance. We illustrate the estimation method on some real data sets.     

Information preserving statistical obfuscation

The problem of limiting the disclosure of information gathered on a set of companies or individuals (the respondents) is considered, the aim being to provide useful information while preserving confidentiality of sensitive information. The paper proposes a method which explicitly preserves certain information contained in the data. The data are assumed to consist of two sets of information on each respondent: public data and specific survey data. It is assumed in this paper that both sets of data are liable to be released for a subset of respondents. However, the public data will be altered in some way to preserve confidentiality whereas the specific survey data is to be disclosed without alteration. The paper proposes a model based approach to this problem by utilizing the information contained in the sufficient statistics obtained from fitting a model to the public data by conditioning on the survey data. Deterministic and stochastic variants of the method are considered.     

东方与西方历史观的对话--与美国学者萨米尔@皮尔逊就历史观念的探讨

皮尔逊教授从文化传统差异的角度论述了中国史学研究中对"客体”的过度偏重,以及西方学者更注重主观参与与历史客观的结合的两种不同的历史观念及其利弊得失.中方学者在一定程度上肯定了皮尔逊教授观点的同时,还指出了道德评价在历史研究中的意义,认为历史研究既要主观地从多种角度去考察,又不能淡化原始文献的客观性.