Lognormal Approximations of Fault Tree Uncertainty Distributions

Fault trees are used in reliability modeling to create logical models of fault combinations that can lead to undesirable events. The output of a fault tree analysis (the top event probability) is expressed in terms of the failure probabilities of basic events that are input to the model. Typically, the basic event probabilities are not known exactly, but are modeled as probability distributions: therefore, the top event probability is also represented as an uncertainty distribution. Monte Carlo methods are generally used for evaluating the uncertainty distribution, but such calculations are computationally intensive and do not readily reveal the dominant contributors to the uncertainty. In this article, a closed‐form approximation for the fault tree top event uncertainty distribution is developed, which is applicable when the uncertainties in the basic events of the model are lognormally distributed. The results of the approximate method are compared with results from two sampling‐based methods: namely, the Monte Carlo method and the Wilks method based on order statistics. It is shown that the closed‐form expression can provide a reasonable approximation to results obtained by Monte Carlo sampling, without incurring the computational expense. The Wilks method is found to be a useful means of providing an upper bound for the percentiles of the uncertainty distribution while being computationally inexpensive compared with full Monte Carlo sampling. The lognormal approximation method and Wilks’s method appear attractive, practical alternatives for the evaluation of uncertainty in the output of fault trees and similar multilinear models.     

论间接故意与过于自信的过失 --理论与实际的矛盾

间接故意与过于自信的过失是犯罪构成中主观方面最容易混淆的两种罪过,本文对这两种罪过进行了系统的比较,并对两者的实际操作中所体现的矛盾进行了分析,最后文章对矛盾提出了解决的方案。     

谈大型字典引《篇海》时存在的问题

《篇海》是古代字书收字最多的字典，也是第一部按笔画数序排字的大型字典。该书保存了大量珍贵资料，有重要的价值。但该书在异体字处理方面存在许多问题，对异体字和正字的关系缺乏必要的说明与沟通。论文对后代大型字典引《篇海》在异体字收录、辨析等方面存在的问题进行了分析。     

《汉语大字典》书证疏误举例

《汉语大字典》在义项的书证方面存在一些疏误,内容涉及书证欠妥、书证有误、引文失误、一例两用等问题。     

论缔约过失责任制度——兼评合同自由与合同正义

缔约过失责任制度的产生与发展是 19世纪下半叶尤其是 2 0世纪以来合同法走向现代化的重要标志之一。缔约过失责任制度的价值论基础 ,就在于诚实信用原则所体现的正义价值与合同自由原则所体现的自由价值构成相倚的两极 ,产生相互亲和的张力。加强对我国缔约过失责任制度的深入研究 ,评析其得失 ,有助于进一步完善我国缔约过失责任制度     

隋唐音义反切研究的观念与方法之检讨

上世纪隋唐音义反切研究取得了很大成就 ,但研究的方法与观念有必要重新检讨。本文认为音义反切传承自正音 ,不以某地方音为取音标准 ,讨论了以《广韵》为参照系的利弊 ,强调要注重对特殊反切的研究 ,只有这些特殊反切才透露出作者的方音信息     

基于规则的MCD磨粒信息诊断专家系统

研究了一种用于发动机磨损状态监测与故障诊断的MCD磨粒信息诊断专家系统 (ES)。首先讨论了诊断知识的获取与规则表示方法 ,接着根据面向对象模板化设计思想 ,研究了一种知识库、推理机和人机界面的一体化构造策略 ,并在此基础上引入深度优先搜索、反向引导正向控制的启发性推理机制     

电子信息专业词典的研究与应用

介绍了一种电子信息专业词典。该词典在0FFICE的ACCESS软件平台上设计开发,成为一种专业术语的数据库系统。该系统具有编辑和查询两大功能,录入了上万条电子信息专业词汇。利用系统的编辑功能,还可以对词汇动态更新,弥补了一般专业词典更新缓慢的缺陷。词典结合教学内容对词条的专业解释,使词典成为某种意义上的电子专业百科书,有助于拓展学生的专业知识和教学工作。     

好词典也有"翻译腔"

就英语学习者而言,拥有一本词典十分必要,否则可能寸步难行;但若要学好英语,一本好词典显得尤其必要。然而,好词典亦如白玉,偶有瑕疵也不足为奇,但尽力减少、避之则是编者们当努力的方向。本文以《英汉大词典》为例一述管窥之见。     

Wide Diameters of Cartesian Product Graphs and Digraphs

In graph theory and study of fault tolerance and transmission delay of networks, connectivity and diameter of a graph are two very important parameters and have been deeply studied by many authors. Wide diameter combining connectivity with diameter is a more important parameter to measure fault tolerance and efficiency of parallel processing computer networks and has received much attention in the recent years. Diameter with width k of a graph G is defined as the minimum integer d for which between any two distinct vertices in G there exist at least k internally disjoint paths of length at most d. In the present paper, the tight upper bounds of wide diameter of the Cartesian product graphs are obtained. Some known results can be deduced or improved from ours.