Order statistics from non-identical right-truncated Lomax random variables with applications

In this paper, we derive some recurrence relations for the single and the product moments of order statistics from n independent and non-identically distributed Lomax and right-truncated Lomax random variables. These recurrence relations are simple in nature and could be used systematically in order to compute all the single and product moments of all order statistics in a simple recursive manner. The results for order statistics from the multiple-outlier model (with a slippage of p observations) are deduced as special cases. We then apply these results by examining the robustness of censored BLUE's to the presence of multiple outliers. Received: November 30, 1998; revised version: March 8, 2000     

Polynomial Factorization for Servers with Semi-Markovian Workload: Performance and Numerical Aspects of a Verified Solution Technique

Abstract

We investigate polynomial factorization as a classical analysis method for servers with semi-Markov arrival and service processes. The modeling approach is directly applicable to queueing systems and servers in production lines and telecommunication networks, where the flexibility in adaptation to autocorrelated processes is essential.

Although the method offers a compact form of the solution with favourable computation time complexity enabling to consider large state spaces and system equations of high degree, numerical stability is not guaranteed for this approach. Therefore we apply interval arithmetic in order to get verified results for the workload distributions, or otherwise to indicate that the precision of the computation has to be improved. The paper gives an overview of numerical and performance aspects of factorization in comparison to alternative methods.     

Non-linear models 1

This is the first application of a new method for testing stationary random point processes. Consider the class of all stationary ergodic point processes on the real line with arbitrary dependences among the inter–point distances (spacing).The hypothesis is :The observed process φ is a homogeneous Poisson process or more (resp.less) regular than a Poisson process.The sample is the vector of the first n points t₁, …,t_n.There is a close relation between our method for testing and queueing theory: For finding an appropriate test statistic, we observe the behaviour of a single server queue with the input φ.A table of critical values is given.     

Allometric Scaling: Analysis of LD50 Data

The need to identify toxicologically equivalent doses across different species is a major issue in toxicology and risk assessment. In this article, we investigate interspecies scaling based on the allometric equation applied to the single, oral LD ₅₀ data previously analyzed by Rhomberg and Wolff.⁽ 1 ⁾ We focus on the statistical approach, namely, regression analysis of the mentioned data. In contrast to Rhomberg and Wolff's analysis of species pairs, we perform an overall analysis based on the whole data set. From our study it follows that if one assumes one single scaling rule for all species and substances in the data set, then β= 1 is the most natural choice among a set of candidates known in the literature. In fact, we obtain quite narrow confidence intervals for this parameter. However, the estimate of the variance in the model is relatively high, resulting in rather wide prediction intervals.     

基于三维校正的SHGC物体三维结构提取方法

针对SHGC(straight homogeneous generalized cylinders)图像的特点与从单幅图像中提取三维信息困难,设计了一种基于单幅SHGC图像和三维校正的三维结构提取方法。与传统的SHGC三维结构提取方法不同,该方法从三维空间中匹配的角度出发,构造一个二维横截面,在二维横截面上增加一个z轴,通过平移、旋转预先构造好的三维横截面,将构造好的横截面与原图像中SHGC物体的横截面进行兴趣点匹配,从而确定最优化结果时的仿射成像参数(λ,θ),通过成像参数可以成功提取SHGC横截面的三维信息,结合SHGC的子午线轮廓信息定性地得到整个SHGC物体的三维信息,提取SHGC表面的纹理,通过三角网格的方法将纹理贴到三维物体表面。实验论证了本文提出的三维结构提取方法是可行的和正确的。     

"灵感是诗的受孕"--艾青诗读记

艾青在上世纪 30年代的诗歌创作中“奉灵感为至圣” ,写出了很多富有魅力的佳作。他的灵感有三种类型 :定向涌流 ;感物触怀 ;彼此重合 ,都属对题材的“二次处理”。但在 4 0年代和 5 0年代 ,他的灵感失落 ,只凭“一次处理”写诗 ,创作陷入低谷。改革开放后 ,沉默多年的艾青重返诗坛 ,灵感回归 ,诗歌创作达到新高峰。     

Single Parenthood and Children’s Reading Performance in Asia

Using the data from Program for International Student Assessment, I examine the gap in reading performance between 15‐year‐old students in single‐parent and intact families in 5 Asian countries in comparison to the United States. The ordinary least square regression analyses show negligible disadvantages of students with a single parent in Hong Kong and Korea, once students’ demographic characteristics and socioeconomic background are held constant. Students in single‐parent families in Indonesia and Thailand outperform their peers in intact families. The negative effect of single parenthood remains significant in Japan, even after parent‐child communication is controlled. Interpreting the weak effect of single parenthood in the Asian countries, I consider extended family systems and the relatively high proportion of widowhood among causes of single parenthood.     

School's out! Why earlier among children of lone parents?

The aims of this population-based study were to analyse educational attainment at ages 24–25 among children of lone parents in comparison with children living with two biological parents, to increase understanding of the factors that seem to be of major importance in increased risks of lower educational achievement and to examine how the life circumstances of non-custodial parents influence possible differences. We found that children who grew up with only one parent showed lower educational attainment than did children in two-parent families. Poorer educational performance on the part of the offspring of lone parents can be explained to a large extent by socio-economic disadvantage, especially a lack of economic resources. However, achievement varies according to cause of lone parenting, and findings strongly indicate that adjusting solely for custodial parents' circumstances may lead to under-estimation of the relationship. Lone parenting seems to have a more detrimental effect on girls' education, and also within groups of children with highly educated parents than among those with a relatively low level of education.     

略论单音反义形容词的句法分布

单音反义形容词 (如“大—小”)的句法分布可分三类 :其一为单一性分布 ,即在某个句法位序上只出现一个反义形容词 ,其间又分为可替换和不可替换两类。其二为同现性分布 ,指一组反义形容词同时出现在某个短语或复句格式中 ,其结构关系有并列、顺承、转折、选择、并列否定、叠合否定等。其三为变异性分布 ,包括单音反义形容词转换成叠合式的内部结构变异 ,也包括不同句法成分转换的外部功能变异。     

单晶中植入纳米晶微结构及光电性能研究

单晶α-Al_2O_3、MgO、YSZ和TiO_2在室温下分别注入Ni~ 和Zn~ 离子,然后在氧化气氛中退火,以形成金属及其氧化物纳米晶．形成的纳米复合结构分别采用X射线光电子能谱(XPS)表征各元素化学价态;用X射线衍射分析(XRD)检测纳米结构的结晶形态;用透射电子显微分析(TEM)观察纳米晶的微观结构及分布情况;吸收光谱和荧光光谱分别用来表征纳米复合结构的宏观光学性能;超导量子干涉磁强计(SQUID)测量磁性纳米晶的矫顽力及截止温度．研究表明:在几种单晶材料中分别形成的金属Ni和Zn具有表面等离子共振吸收效应,ZnO纳米晶具有较强的绿光发射,铁磁性金属Ni纳米晶具有比常规块材大的矫顽力。这些性能在光学滤波片、蓝/绿发光器件和磁存储器方面板具应用前景．