A Distribution-Free Control Chart Based on Order Statistics

In this article, we introduce a new distribution-free Shewhart-type control chart that takes into account the location of a single order statistic of the test sample (such as the median) as well as the number of observations in that test sample that lie between the control limits. Exact formulae for the alarm rate, the run length distribution, and the average run length (ARL) are all derived. A key advantage of the chart is that, due to its nonparametric nature, the false alarm rate and in-control run length distribution are the same for all continuous process distributions, and so will be naturally robust. Tables are provided for the implementation of the chart for some typical ARL values and false alarm rates. The empirical study carried out reveals that the new chart is preferable from a robustness point of view in comparison to a classical Shewhart-type chart and also the nonparametric chart of Chakraborti et al. (2004 Chakraborti , S. , van der Laan , P. , van de Wiel , M. A. ( 2004 ). A class of distribution-free control charts . J. Roy. Statist. Soc. Ser. C-Appl. Statist. 53 ( 3 ): 443 – 462 .[Web of Science ®] , [Google Scholar]).     

PITMAN-CLOSENESS AS A MEASURE TO EVALUATE THE QUALITY OF FORECASTS

ABSTRACT

We consider Pitman-closeness to evaluate the performance of univariate and multivariate forecasting methods. Optimal weights for the combination of forecasts are calculated with respect to this criterion. These weights depend on the assumption of the distribution of the individual forecasts errors. In the normal case they are identical with the optimal weights with respect to the MSE-criterion (univariate case) and with the optimal weights with respect to the MMSE-criterion (multivariate case). Further, we present a simple example to show how the different combination techniques perform. There we can see how much the optimal multivariate combination can outperform different other combinations. In practice, we can find multivariate forecasts e.g., in econometrics. There is often the situation that forecast institutes estimate several economic variables.     

Tests for Symmetry Based on the One-Sample Wilcoxon Signed Rank Statistic

ABSTRACT

The one-sample Wilcoxon signed rank test was originally designed to test for a specified median, under the assumption that the distribution is symmetric, but it can also serve as a test for symmetry if the median is known. In this article we derive the Wilcoxon statistic as the first component of Pearson's X ² statistic for independence in a particularly constructed contingency table. The second and third components are new test statistics for symmetry. In the second part of the article, the Wilcoxon test is extended so that symmetry around the median and symmetry in the tails can be examined seperately. A trimming proportion is used to split the observations in the tails from those around the median. We further extend the method so that no arbitrary choice for the trimming proportion has to be made. Finally, the new tests are compared to other tests for symmetry in a simulation study. It is concluded that our tests often have substantially greater powers than most other tests.     

On the existence and uniqueness of the MLEs of the parameters of a general class of exponentiated distributions

In this paper, we present a formal simple proof for the existence and uniqueness of the maximum likelihood estimates (MLEs) of the parameters of a general class of exponentiated distributions. This class includes the exponentiated (general) exponential, exponentiated Rayleigh (scaled Burr X) and exponentiated Pareto distributions, as special cases, and thus the proof given here establishes the existence and uniqueness of the MLEs for these important special cases as well.     

继承与创新：沃尔兹新现实主义理论定位再探讨

肯尼思·沃尔兹的新现实主义是国际政治研究的里程碑,但学界对这一里程碑含义的理解可能存在偏差。这一理论不是国际政治研究科学化的起点,而是对古典现实主义核心论点的历史性再诠释。沃尔兹和其他古典现实主义者一样认为人的理性能力存在限度,相信实力对比是进行利益划分的客观依据,劝告政治家遵行责任伦理。古典现实主义者与沃尔兹之间的差异并没有想象的大,古典现实主义者也强调安全,他们发现国际政治中存在着安全困境,追求过多权力会导致不安全,国家追求权力应适可而止。古典现实主义者还发现世界政治中因果关系非常复杂,事件的结果绝少和当事者的动机一致,“事与愿违”是政治中的常态,这与沃尔兹强调的“系统效应”相似。新古典现实主义者试图将沃尔兹的理论进一步科学化,他们希望结合结构变量与单元变量,提出更科学的理论解释、预测国家的行为,这不仅误解了沃尔兹,也背离了现实主义传统。     

脐橙氮、磷矿质营养的运转分配规律和座果机制的研究

本试验选择朋娜脐橙（Skagg’sBonanzaNavel）,在萌芽期和花芽分化期叶片施用15N硫铵,(32)P磷酸二氢纳和(15)N尿素,研究脐橙在萌芽期、初花期、生理落果期以及花芽分化期氮、磷营养吸收运转分配规律．结果表明开花这个生理过程需消耗大量氮、磷营养．同时在落花落果期,落花落果的(32)P放射比强度和NDFF％都比座果的小,说明,氮磷营养条件是引起脐橙落花落果的主要原因之一．而且,GA3＋BA,GA3激素处理能吸引氮磷营养向幼果运输,此结果与GA3＋BA,GA3处理提高座果率和减少落果率相一致．     

微乳液聚合制备聚丙烯酰胺及聚N-异丙基丙烯酰胺超细微粒

研究了琥珀酸双（２－乙基己酯）磺酸钠（ＡＯＴ）、甲苯（Ｔ）、乙酰胺（ＥＭ）、丙烯酰胺（ＡＭ）、Ｎ－异丙基丙烯酰胺（ＮＩＰＡＭ）、Ｎ,Ｎ－亚甲基双丙烯酰胺（ＢＩＳ）、水组成的六种微乳液体系,以电导法和目视法测定了其相区临界点电导率,并绘制了各自的拟三元相图;以偶氮二异丁腈（ＡＩＢＮ）为引发剂,在微乳液中制备了聚丙烯酰胺及聚Ｎ－异丙基丙烯酰胺超细微粒．用ＩＲ谱对其进行了验证,以扫描电镜观察了其外部结构特征,测得微粒平均粒径为０．０５～０．１０μｍ．实验表明,可在微乳液中制备ＰＡＭ及ＰＮＩＰＡＭ超细微粒．     

The Singularity of the Information Matrix of the Mixed Proportional Hazard Model

This paper presents new identification conditions for the mixed proportional hazard model. In particular, the baseline hazard is assumed to be bounded away from 0 and ∞ near t = 0. These conditions ensure that the information matrix is nonsingular. The paper also presents an estimator for the mixed proportional hazard model that converges at rate N^−1/2.     

言语行为理论视角下的X BE X结构语用意义分析

X BE X结构是一种特殊的判断句。表面上看起来主语和表语重复,传递的是"零信息",但它却蕴含着丰富的语用含义,传递着说话人的交际意图,是说话人有意选择的一种言语行为。基于言语行为理论,一个完整的言语行为是由言内、言外和言后三个层次共同作用完成的。本文从言语行为理论出发,认为X BE X结构的意义解读可以从言内行为上完成对词义的解读,从言外行为来表达交际意图,从言后行为来实现交际意图。     

“A＋N”的认知研究

文章从认知语言学的角度出发,对＂A＋N＂结构进行全面的考察,包括原型理论、构式、隐喻、成分意义等。指出＂,A＋N＂结构从一个侧面反映了人类认知的体验基础,以及认知遵循的从简单到复杂、从客观到主观的基本规律,而隐喻则是人类认识不断深化的重要机制之一。隐喻具有突破语义限制的作用,其产生的结果可使＂A＋N＂的意义固化,从而形成习语和惯用语。