An isotonic regression algorithm

A ‘pooling sets’ type of algorithm is developed and shown to be valid for computing an isotonic regression function for a general quasi-order. The method is direct and intuitive. The algorithm works best when the quasi-order is complex and the objective function is nearly isotonic. An example is worked out in detail.     

论作为具体概念的"三个代表"

江泽民同志提出的"三个代表"重要思想,是认识不断深化的产物,是处于辩证体系中的概念,是取得了理想形态的概念.反映具体性思维的"三个代表",必将对新时期邓小平理论新的阐述和新的发展作出自己独特的理论贡献.     

英语习得过程中的过渡语和语言石化

针对英语习得过程中的过渡语的石化现象,从母语迁移、培训转移、学习策略等5个方面探讨了石化现象产生的原因及过渡语的发展过程;分析了母语迁移中的正向迁移以及作为一种外语的英语变体——“中国英语”的形成;指出过渡语阶段易出现的负向迁移、过度概括、规则的不完整应用等错误;提出了在习得目的语的过渡阶段适当提高目的语输入质量,正确估测学生的语言熟练程度等对策,以提高二语习得者的外语学习能力。     

Z-4-(对-溴苯硫基)-3-(对-硝基苯甲酰氧基)-3-丁烯-2-酮的立体选择性合成和Diels-Alder反应活性研究

合成了一个新的α ,β取代 3-丁烯 - 2 -酮 (CH3COC(p -NO2 C6 H4 COO - ) =CH-S -C6 H4 Br - p) (4) ,用元素分析 ,核磁共振波谱和X -衍射对其结构进行了表征 ,并对其构型和Diels -Alder反应活性进行了探讨 .结果表明只有Z构型的产物生成 ,Z - 4 -溴 - 3-(对一硝基苯甲酰氧基 ) - 3-丁烯 - 2 -酮可与丁二烯型化合物发生Diels -Alder反应 ,而标题化合物在相似条件下不能发生Diels -Alder反应     

台湾问题:危机深化,转机何在?

台湾问题之转机与出路在于 ,台湾当局应顺应历史发展潮流 ,调整过时的“戒急用忍”政策 ,回到“九二共识”、承认“一中”原则、重启协商机制的轨道上来 ,并以“先易后难”的务实原则 ,优先发展两岸经贸技术合作 ,以化解两岸对峙僵局 ,纾解台湾政经危机。     

The Cox Proportional Hazards Model with a Partly Linear Relative Risk Function

The conventional Cox proportional hazards regression model contains a loglinear relative risk function, linking the covariate information to the hazard ratio with a finite number of parameters. A generalization, termed the partly linear Cox model, allows for both finite dimensional parameters and an infinite dimensional parameter in the relative risk function, providing a more robust specification of the relative risk function. In this work, a likelihood based inference procedure is developed for the finite dimensional parameters of the partly linear Cox model. To alleviate the problems associated with a likelihood approach in the presence of an infinite dimensional parameter, the relative risk is reparameterized such that the finite dimensional parameters of interest are orthogonal to the infinite dimensional parameter. Inference on the finite dimensional parameters is accomplished through maximization of the profile partial likelihood, profiling out the infinite dimensional nuisance parameter using a kernel function. The asymptotic distribution theory for the maximum profile partial likelihood estimate is established. It is determined that this estimate is asymptotically efficient; the orthogonal reparameterization enables employment of profile likelihood inference procedures without adjustment for estimation of the nuisance parameter. An example from a retrospective analysis in cancer demonstrates the methodology.     

实现服务型政府目标的思考

服务型政府的目标是促使人人做贡献,人人都成才,为此,破除束缚人才发展的体制与制度,加大人力资源投入,畅通人才流动的渠道,优化人才成才的环境,乃是实现这一目标的有效途径。     

上市公司业绩评价模型与实证分析、

近年来,业绩评价受到越来越多的关注。在目前理论界上市公司业绩评价指标体系的基础上,本文引偏最小二乘回归方法进行实证分析,发现可以得到较好的预测上市公司未来中长期的业绩的模型。     

The cost of not knowing the radius

Robust Statistics considers the quality of statistical decisions in the presence of deviations from the ideal model, where deviations are modelled by neighborhoods of a certain size about the ideal model. We introduce a new concept of optimality (radius-minimaxity) if this size or radius is not precisely known: for this notion, we determine the increase of the maximum risk over the minimax risk in the case that the optimally robust estimator for the false neighborhood radius is used. The maximum increase of the relative risk is minimized in the case that the radius is known only to belong to some interval [r _l ,r _u ]. We pursue this minmax approach for a number of ideal models and a variety of neighborhoods. Also, the effect of increasing parameter dimension is studied for these models. The minimax increase of relative risk in case the radius is completely unknown, compared with that of the most robust procedure, is 18.1% versus 57.1% and 50.5% versus 172.1% for one-dimensional location and scale, respectively, and less than 1/3 in other typical contamination models. In most models considered so far, the radius needs to be specified only up to a factor , in order to keep the increase of relative risk below 12.5%, provided that the radius–minimax robust estimator is employed. The least favorable radii leading to the radius–minimax estimators turn out small: 5–6% contamination, at sample size 100.      

An Optimal Confidence Region for the Largest and the Smallest Means from a Multivariate Normal Distribution

An optimal confidence region is proposed for obtaining the largest and the smallest means of a multivariate normal distribution with a common unknown variance and a non-negative correlation coefficient. The confidence region is compared to a class of asymmetric confidence regions, and the results show that it is uniformly better. Further, a design-oriented two-stage confidence region with a fixed width is also given. Finally, the optimal confidence region is applied to an experiment to measure the treatment effectiveness of a physical therapy with four independent groups and the result reveals that the proposed confidence region can provide some useful information.