A New Approach to Reliability Prediction

A new approach determines the reliability function for systems with constant transition rates and with standby and repair, using the stochastic transition signal-flow graph. All the state probabilities of the system need not be found; instead the source-to-sink transmission is calculated. A model in the form of a stochastic transition signal-flow-graph is developed for these systems. Many results reported in the literature can be obtained from the model.     

用新的思路发展新网管

介绍了北京通信网管系统的现状；又从4个方面阐述了新一代网管系统的发展方向。最后对网管网络的结构改进及其功能的提高与完善问题，进行了结合实际的探讨。     

一种新的大规模网络主动预警方法

网络的全球化发展决定网络安全向整体性和动态性发展,互联网的分散管理机制使得监控管理域外的网络安全状态变得非常困难.本文基于网络透视技术,提出一种新的大规模网络主动预警方法,可以对无控制权的网络进行实时监控和主动预警.当网络发生异常行为时,能够准确检测异常来源,缩小异常定位范围,对于大规模网络异常行为的检测和预防具有重要现实意义.以中国教育网拓扑结构为背景的仿真实验表明,该方法有效,对网络安全具有重要的研究意义和实用价值.     

一种针对软错误的程序可靠性定量分析方法

 宇宙射线辐射所导致的软错误是航天计算面临的最主要挑战之一.而随着集成电路制造工艺的持续进步,现代处理器的计算可信性日益面临着软错误的严重威胁.当前,很少有研究从软件角度分析软错误对系统可靠性的影响.在程序汇编代码的基础上,提出一种针对软错误的程序可靠性定量分析方法PRASE,并且提出基本块分析法和3条运算定律以改进其分析效率.实验表明软错误对程序可靠性的影响与程序自身结构密切相关,同时分析结果还指出在软错误影响下程序的关键脆弱点,对实现针对软错误的高效容错算法有参考意义.     

A New Sample-Based Approach to Predict System Performance Reliability

Multiple degradation paths arise when systems operate under uncontrolled, uncertain environmental conditions at customers' hands in the field. This paper presents a design stage method for assessing performance reliability of systems with competing time-variant responses due to components with uncertain degradation rates. Herein, system performance measures (e.g. selected responses) are related to their critical levels by time dependent limit-state functions. System failure is defined as the non-conformance of any response, and hence unions of the multiple failure regions are formed. For discrete time, set theory establishes the minimum union size needed to identify a true incremental failure region that emerges from a safe region. A cumulative failure distribution function is built by summing incremental failure probabilities. A practical implementation of the theory is manifest through evaluating probabilities by Monte Carlo simulation. Error analysis suggests ways to predict and minimize errors. An electrical temperature controller shows the details of the method, and the potential of the approach. It is shown that the proposed method provides a more realistic way to predict performance reliability than either worst-case, or simple average-based approaches that are available in the open literature.     

A New Algorithm for Symbolic System Reliability Analysis

This paper presents a new algorithm for symbolic system reliability analysis. The method is applicable to system graphs with unreliable branches or nodes. Each branch is directed or undirected. Element probabilities need not be equal, but their failures are assumed to be s-independent. The new method makes no attempt to generate mutually exclusive events from the set of paths or cutsets but uses a technique to reduce greatly the number of terms in the reliability expression. Actual programming results show that the new method can efficiently handle systems having fewer than 20 paths or cutsets between the input-output node pair.     

A New Discretization Approach With Application in Reliability Estimation

This paper introduces a new discretization technique that retains the basic structure of the failure rate function of the original life distribution. Earlier approaches for discretizing a continuous random variable, reported in the literature so far, are moment equalization, and discrete concentration techniques. This proposed approach has been used for approximating the reliability of complex systems where exact determination of survival probability is analytically intractable. These applications show a reasonable degree of closeness between this new method and the simulated results. Admissibility of the proposed method over the methods of discrete concentration and numerical integration has also been established.     

A New Improved Method for Symbolic Reliability Analysis

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A Unified Formula for Analysis of Some Network Reliability Problems

A topological formula is derived for solving a variety of network reliability problems such as vertex-to-vertex communication from a source to a terminal; from a source to some specified subset of the vertices or else all vertices; between any given vertex-pair; between all vertex-pairs within a given subset of the vertices; or else between all vertex-pairs. The formula applies to networks consisting of imperfect (unreliable) vertices and/or links, and with failure events s-independent or not. The formula explicitly characterizes the structure of both cancelling and noncancelling terms in the reliability expression obtained by Inclusion-Exclusion, and involves only noncancelling terms. Earlier topological formulas for the source-to-terminal problem and the source-to-all-vertices problem are shown to be special cases of this new one.     

A Delta-Star Transformation Approach for Reliability Evaluation

This paper presents new exact expressions for delta-star transformation to simplify complex reliability block diagrams consisting 2-state or 3-state devices. The conditions are given under which the transformation applies. The expressions are interrelated and require less computation time for finding equivalent star configuration. Expressions can also be derived for star-delta transformation in the same way.     

评估交换超立方体网络可靠性的一种新方法

交换超立方体互连网络作为大规模处理器系统网络模型的重要候选之一,其可靠性问题一直为人们所关注。该文利用额外连通度作为评价可靠性的重要度量,对交换超立方体互连网络的可靠性进行分析,得到了交换超立方体网络的2-额外点连通度(k2(EH(s, t)))和2-额外边连通度(2(EH(s, t))),证明了当ts2时,(k2(EH(s, t))=3s-2;当ts3时,2(EH(s, t))=3s-1。分析说明了对交换超立方体互连网络的可靠性评价时,2-额外连通度较之传统连通度更具有优势性。     

一种有共因失效的网络系统可靠性分析方法

在分析网络系统可靠性时,由于其诸多部分是冗余系统,共因(CCF)失效是必须考虑的因素.传统的共因方法分为显式方法和隐式方法,显武方法由于要引入大量共因失效基本事件,造成模型的复杂和难以求解;而隐式方法有较大的主观性,结果往往不够精确.本文基于决策二叉树(BBD)的共因分析法,能方便的进行计算同时得到了较理想的精确结果.     

A New Algorithm for the Reliability Analysis of Multi-Terminal Networks

In a probabilistic network, source-to-multiple-terminal reliability (SMT reliability) is the probability that a specified vertex can reach every other vertex. This paper derives a new topological formula for the SMT reliability of probabilistic networks. The formula generates only non-cancelling terms. The non-cancelling terms in the reliability expression correspond one-to-one with the acyclic t-subgraphs of the network. An acyclic t-subgraph is an acyclic graph in which every link is in at least one spanning rooted tree of the graph. The sign to be associated with each term is easily computed by counting the vertices and links in the corresponding subgraph. Overall reliability is the probability that every vertex can reach every other vertex in the network. For an undirected network, it is shown the SMT reliability is equal to the overall reliability. The formula is general and applies to networks containing directed or undirected links. Furthermore link failures in the network can be s-dependent. An algorithm is presented for generating all acyclic t-subgraphs and computing the reliability of the network. The reliability expression is obtained in symbolic factored form.     

基于粗糙集的复杂系统网络可靠性评价新方法

本文提出了一种基于粗糙集的复杂系统网络可靠性评价新方法。本方法首先利用粗糙集属性约简原理删除冗余指标,然后利用粗糙集属性重要度原理确定各指标权重,最后采用线性加权法得到综合评价结果。结合某复杂通信系统网络可靠性评价实例进行分析。结果表明,本文方法所得评价结果比专家评价法结果更加客观、合理,证明了本文方法的有效性和优越性。     

A Method for Calculation of Network Reliability

The calculation of the probability that communication between two nodes in a given network is disrupted is difficult when the number of channels is large or when the network configuration is complex. This paper presents an efficient method, formalized as an algorithm, for calculating this probability using subnetworks that are smaller than the original one. This algorithm should prove useful in practice since it permits the possibility of choosing the subnetwork decomposition that one considers best suited for a specific problem.     

A Recursive Method Based on Case Analysis for Computing Network Terminal Reliability

In this paper a unified treatment is provided of the methods for computing terminal reliability based on recursive case analysis. The possible choices in case enumeration are discussed, and a rationale is given to support a particular policy. Simplification and decomposition techniques are also examined, and some experimental results are described, obtained with a computer program, which is a good compromise between efficiency and simplicity.     

WDM网络设计中与可靠性相关问题的分析

分析了基于可靠性的WDM网络设计中单波道可用度取定、备用波道设置等问题，并结合实际参数，给出了定量计算。     

A Modified Technique for Computing Network Reliability

Ahmad (1982) has published a technique to compute the reliability of a network without resorting to paths or cutsets. However, the technique uses a random choice of next node connected to the previous node in the construction of a tree. This approach can lead to a large number of terms in the reliability expression. Our modified version of the Ahmad technique always produces a reliability expression with the same or fewer terms as the original technique.     

A Simple Technique for Computing Network Reliability

A tree construction technique to compute a reliability expression of a network is derived. The technique is straight forward and good for both directed and undirected graphs. It gives mutually disjoint success branches. The reliability expression of each branch can be directly written by a set of rules. The reliability of the network can then be obtained by taking the direct sum of the reliabilities of the branches. It involves fewer multiplications than other known techniques. For a moderately complex network it is very easy to use this technique for evaluating reliability.