Detecting influential observations in Liu and modified Liu estimators

In regression, detecting anomalous observations is a significant step for model-building process. Various influence measures based on different motivational arguments are designed to measure the influence of observations through different aspects of various regression models. The presence of influential observations in the data is complicated by the existence of multicollinearity. The purpose of this paper is to assess the influence of observations in the Liu [9] and modified Liu [15] estimators by using the method of approximate case deletion formulas suggested by Walker and Birch [14]. A numerical example using a real data set used by Longley [10] and a Monte Carlo simulation are given to illustrate the theoretical results.     

Robust test for means when population variances are unequal

We consider the problem of testing the equality of two population means when the population variances are not necessarily equal. We propose a Welch-type statistic, say T^* _c, based on Tiku!s ‘1967, 1980’ modified maximum likelihood estimators, and show that this statistic is robust to symmetric and moderately skew distributions. We investigate the power properties of the statistic T^* _c; T^* _c clearly seems to be more powerful than Yuen's ‘1974’ Welch-type robust statistic based on the trimmed sample means and the matching sample variances. We show that the analogous statistics based on the ‘adaptive’ robust estimators give misleading Type I errors. We generalize the results to testing linear contrasts among k population means     

相控阵雷达低仰角目标DOA估计的算法

在相控阵雷达跟踪低仰角目标时,采用频率捷变技术可以有效地减小雷达回波中直射信号和反射信号的相关性,抑制多径效应对目标到达方向估计造成的影响,提高角度估计的精度和性能。再用修正的AR模型算法,不仅可以在此基础上进一步去掉这两种信号的相关性,而且能正确估计出目标和镜像的仰角。计算机仿真实验结果验证了频率捷变和修正AR模型算法理论的正确性,以及在与其他方法比较的情况下,两者结合在去相关性能上的优越性和工程实用性。     

转基因食品安全性的人类健康伦理原则探析

随着转基因食品在全球的迅猛发展,学者和公众对它的安全性表示了极大的关注。转基因食品是否危害人类健康,一直是人们所担心的事。作者运用伦理学的基本原则对支持和反对两种观点进行了分析,提出对转基因食品应该采取“有罪推定”的战略。     

全球转基因食品研究最新进展及对策

概述了作为食品应用的转基因生物的国内外研究进展及推广应用情况,纵观全球转基因食品的发展态势及各国政府对发展转基因食品的态度,对我省应当如何开展转基因技术研究和发展转基因食品产业提出相应的对策。     

Oligarchy for Social Choice Correspondences and Strategy-Proofness

We study the existence of a group of individuals which has some decisive power for social choice correspondences that satisfy a monotonicity property which we call modified monotonicity. And we examine the relation between modified monotonicity and strategy-proofness of social choice correspondences according to the definition by Duggan and Schwartz (2000). We will show mainly the following two results. (1) Modified monotonicity implies the existence of an oligarchy. An oligarchy is a group of individuals such that it has some decisive power (semi-decisiveness), and at least one of the most preferred alternatives of every its member is always chosen by any social choice correspondence. (2) Strategy-proofness of social choice correspondences is equivalent to modified monotonicity.     

医疗侵权中的因果关系——英美侵权行为法视角下的分析

因果关系的认定是医疗侵权案件中的一个难点.文章引用二分法的因果关系理论将因果关系分为事实上的因果关系和法律上的因果关系两个层次,认为对于医疗侵权纠纷,应根据不同的侵权形态,在事实因果关系的认定上分别适用必要条件原则、实质要素原则和"错失机会"原则;在法律因果关系的认定上适用限制性可预见说,并应该充分考虑介入原因、取代原因和政策因素.     

机载SAR斜侧视成像的高效空变算法

针对机载合成孔径雷达ＳＡＲ斜侧视成像的二维处理特性，采用一种全聚焦的处理方法，它能方便地处理斜侧视ＳＡＲ参考函数的空间变化的特性，并提高计算效率。     

液体中热晕的矩阵分析及有关新现象

对液体中热晕现象从新的角度，即矩阵光学的方法进行了处理，以热透镜为模型，建立了热晕效应的等效焦距形成发展过程的数学表达式。同时进行了部分实验以验证理论结果。成功地观察到了热晕形成发展的全部动态过程，得到了与理论计算基本一致的实验数据。在实验中，同时观测到了一些周期性的跳动现象，给出了定性的物理解释。     

后迟滞型风险沟通及其精准治理

随着“外部风险”被“人为风险”替代和主导,西方发达国家积极推动传统风险沟通向现代风险沟通转变。后发国家在全球化风险和本地化风险双重冲击下,呈现出迟滞型风险沟通。我国互联网新媒体浪涌式发展,催化了风险沟通主体与互联网新媒体手段产生“粘合”及“轮推作用”,迟滞型风险沟通由此向后迟滞型风险沟通嬗变。透过转基因食品风险辩论案例交互机制,发现后迟滞型风险沟通存在“局部性突破”和“局部性落差”双重不确定性效果。为此,可通过主动预防型理念、“共同体”结构、“多速整合”机制、“互联网+”手段、政府职能的“五位一体”再造,实现对后迟滞型风险沟通不良后果的精准治理。