Characterizations of geometric distribution and discrete IFR (DFR) distributions using order statistics

Let X be a discrete random variable the set of possible values (finite or infinite) of which can be arranged as an increasing sequence of real numbers a₁<a₂<a₃<…. In particular, a_i could be equal to i for all i. Let X_1n≦X_2n≦?≦X_nn denote the order statistics in a random sample of size n drawn from the distribution of X, where n is a fixed integer ≧2. Then, we show that for some arbitrary fixed k(2≦k≦n), independence of the event {X_kn=X_1n} and X_1n is equivalent to X being either degenerate or geometric. We also show that the montonicity in i of P{X_kn = X_1n | X_1n = a_i} is equivalent to X having the IFR (DFR) property. Let a_i = i and $\text{G(i) = P(X≧i), i = 1, 2, …}$. We prove that the independence of {X_2n ? X_1n ∈B} and X_1n for all i is equivalent to X being geometric, where B = {m} (B = {m,m+1,…}), provided G(i) = q^i?1, 1≦i≦m+2 (1≦i≦m+1), where 0<q<1.     

ROBUST ESTIMATION UNDER TYPE II CENSORING

The properties of robust M-estimators with type II censored failure time data are considered. The optimal members within two classes of ψ-functions are characterized. The first optimality result is the censored data analogue of the optimality result described in Hampel et al. (1986); the estimators corresponding to the optimal members within this class are referred to as the optimal robust estimators. The second result pertains to a restricted class of ψ-functions which is the analogue of the class of ψ-functions considered in James (1986) for randomly censored data; the estimators corresponding to the optimal members within this restricted class are referred to as the optimal James-type estimators. We examine the usefulness of the two classes of ψ-functions and find that the breakdown point and efficiency of the optimal James-type estimators compare favourably with those of the corresponding optimal robust estimators. From the computational point of view, the optimal James-type ψ-functions are readily obtainable from the optimal ψ-functions in the uncensored case. The ψ-functions for the optimal robust estimators require a separate algorithm which is provided. A data set illustrates the optimal robust estimators for the parameters of the extreme value distribution.     

网絡协議TCP/IP

网络协议TCP/IP,分别相当于ISO/OSI参考模式中的第四层和第三层,源于美国国防部ARPANET的协议标准.目前,在高档微机工程工作站中得到广泛的应用,并成为工业界的一个“公认”标准. 本文介绍TCP/IP协议,并结合对B-NET(运行于16位微机DUAL系统83和UNIX系统V)中的TCP/IP的提取和分析,着重说明它们的接口及其执行过程机理.     

中港两地法律冲突的解决原则及其现行的国际私法规范

“一国两制”已从理论的构思即将跨入社会实践阶段.香港特别行政区1997年成立后,我国将出现一崭新的法律现象——“一国两法”。那么在一个主权国家之内,如果存在着不同的法律区域,而这些不同法域民事法律关系的主体又不可避免地要进行交往,这就产生了这种跨区域的民事法律关系受哪一区域的法律调整的问题。这种法律上的矛盾和抵触状态,法律上称之为“区际法律冲突”。     

TM_(010)模圆柱腔GUNN振荡器

本文论述了 TM_(010)模式圆柱腔 GUNN 振荡器的理论基础、设计原理与使用特点。这种振荡器在微波技术中作为中精度、小功率信号源在测量、雷达、微波通信、卫星通信以及微波报警器等方面有广泛的应用。     

Approximation spline de la prevision d'un processus fonctionnel autorégressif d'ordre 1

ABSTRACT We present a method to approximate and forecast, on an entire interval, a continuous-time process. For this purpose, we use the modelization of ARH(l) processes, defined by Bosq (1991). We deal with the practical problem of the discretization of the observed trajectories and approximate them by means of spline functions. We show by simulations that for well-chosen smoothing parameters, good prediction can be obtained in comparison with the “predictable” part of the process. Finally, we apply this model to forecast road traffic and compare it with a SARIMA model.     

金丝猴(Rhinopithecus roxellanae)的野外行为生态学的初步研究

本文主要介绍金丝猴集群的主要特征,在川西北地区,其社群大小变化较大,少则30～40只,多至150～200只,其社群是以众多的类似于“小家庭”为基本单元所组成,而这种以家庭为中心的群体结构形式是直接或间接的与生育繁殖(血缘关系)有关。树栖且活动敏捷,白天觅食活动,晚上静止休息,且对幼仔具有强有效的保护性。     

中华“先蚕”嫘祖考——黄帝正妃嫘祖与本姓后裔的事迹

黄帝正妃嫘祖，同“三皇”与黄帝一样，亦是神话与传说。神与人或人与神兽（或飞禽与虫蛇）相糅合，加之子孙多，迁徙地广，后人营修的祭祀载体均以首代祖先称号命名，因而也就形成多故里、多故居、多陵墓、多祠庙、多祭坛（台）等文化表象。从目前各种资料和研究成果看，传统的嫘祖故里说需要重新审视，河南西平县（西陵古国所在地）应是嫘祖（西陵氏之女）的原生地。     

À propos de l’article de François-Xavier de Vaujany, « Les figures de la gestion du changement sociotechnique »

The approach adopted by François Xavier de Vaujany draws from “structurationist” research in English-speaking social sciences, a current that shares with the sociology of technology a vision of the contextual and negotiated nature of the links between technical and organizational phenomena. Various trajectories in the way organizations use new information and communication technology can be compared; and the role, examined that specific mediators play in the appropriation process. This approach provides stimulating input in discussions about the impact of new technology on organizational change.     

韩剧热播的社会效益及对中国电视剧的启示

近年来，韩国电视剧在儒家文化圈，特别是在中国传媒市场上呈现强劲趋势，给韩国带来了巨大的经济收益，带动了众多相关产业，甚至扭转了其他国家对韩民族的文化偏见。探讨韩剧如何火爆，对中国电视剧的发展有一定的启示。