网络管理中的故障模型

网络故障隔离和诊断在网络管理中是非常重要的。其目的是保证网络提供连续、可靠的服务。但是网络故障的复杂性使该问题很难处理 ,因而研究网络故障是关键。本文描述了网络故障发生的环境 ,提出了一种网络故障模型 ,分析了网络故障的特征 ,并对故障传播问题作了讨论。     

广义Bayes诊断法

系统地阐述了Bayes的诊断思想,推广了多输入单输出诊断方法,对多输入多输出的诊断作出一次尝试,克服以往诊断的局限性,给出一种广泛应用的诊断方法,并通过仿真示例,表现出其可行性及有效性.     

基于神经网络的机载航炮故障诊断专家系统

在分析专家系统和神经网络单独应用于设备故障诊断的优缺点基础上，建立了基于神经网络的机载航炮故障诊断专家系统。实践证明，网络的学习时间显著缩短，整个系统推理效率明显提高，验证了集成式专家系统的诊断效果比传统的专家系统或神经网络更全面、准确和迅速。     

Balance testing and balance-testable design of logic circuits

We propose a low-cost method for testing logic circuits, termed balance testing, which is particularly suited to built-in self testing. Conceptually related to ones counting and syndrome testing, it detects faults by checking the difference between the number of ones and the number of zeros in the test response sequence. A key advantage of balance testing is that the testability of various fault types can be easily analyzed. We present a novel analysis technique which leads to necessary and sufficient conditions for the balance testability of the standard single stuck-line (SSL) faults. This analysis can be easily extended to multiple stuck-line and bridging faults. Balance testing also forms the basis for design for balance testability (DFBT), a systematic DFT technique that achieves full coverage of SSL faults. It places the unit under test in a low-cost framework circuit that guarantees complete balance testability. Unlike most existing DFT techniques, DFBT requires only one additional control input and no redesign of the underlying circuit is necessary. We present experimental results on applying balance testing to the ISCAS 85 benchmark circuits, which show that very high fault coverage is obtained for large circuits even with reduced deterministic test sets. This coverage can always be made 100% either by adding tests or applying DFBT.This research was supported by the National Science Foundation under Grant No. MIP-9200526. Parts of this paper were published in preliminary form in Proc. 23rd Symp. Fault-Tolerant Computing, Toulouse, June 1993, and in Proc. 31st Design Automation Conf, San Diego, June 1994.     

A Novel Dynamic Fault Restoration Mechanism Using a Multiple Ring Approach in WDM Mesh Networks

This work describes a distributed fault restoration algorithm, called the Dynamic Multiple Ring Algorithm (DMRA), for application in WDM mesh networks. This study explores the choice of restoration paths and the assignment of fault-tolerant bandwidth when a link, node, or channel failure occurs according to the change in traffic load, number of nodes, and transmission delay including propagation and switching delays. Accordingly, the primary aim of this work is to use networking segments near faults to share the restoration load throughout a mesh network. Each node searches for restoration paths in their near environment using the proposed DMRA. Nodes use distributed control to search for neighboring nodes and to establish the relationship between them to build numerous logical rings. Nodes can also locate faults in the logical rings. These rings establish the restoration paths. The traffic load over failed links or nodes can be diverted to other paths in the networking segments. The cost of the restoration paths is computed at each node based on both the current capacity and the transmission delay. The selected restoration paths are suitable transmission routes in the network neighborhood. Hence, restoration paths can be identified and wavelength assigned quickly according to network bandwidth and traffic load. Simulation results reveal that the proposed method works extremely quickly and has a high success rate. Consequently, it is very useful for applications in real WDM networks, where the status varies from minute to minute.Corresponding author is presently a guest scientist with the National Institute of Standards and Technology, USA. This research was partially supported by the Grant of National Science Council, ROC (NSC-92-2218-E-155-004 and NSC-93-2917-I-155-001).     

机载电子设备智能故障诊断技术研究

智能故障诊断在现代飞行器及先进的武器装备及其电子设备的设计、生产和维护过程中都起着关键的作用。介绍了现有电子设备智能故障诊断方法,包括基于规则的方法、故障树方法、模糊诊断方法、基于人工神经网络的方法和信息融合故障诊断方法,阐述各自的特点和局限性,讨论了航空电子设备智能故障诊断发展,提出了集成诊断技术、综合测试与诊断策略、机器学习方法和软件工具的开发等关键技术。     

The use of apatite fission track thermochronology to constrain fault movements and sedimentary basin evolution in northeastern Brazil

An apatite fission track study of crystalline rocks underlying sedimentary basins in northeastern Brazil indicate that crustal blocks that occur on opposite sides of a geological fault experienced different thermal histories. Samples collected on the West block yielded corrected fission-track ages from 140 to 375 Ma, whereas samples collected on the East block yielded ages between 90 and 125 Ma. The thermal models suggest that each block experienced two cooling events separated by a heating event at different times. We concluded that the West block moved downward relative to the East block ca. 140 Ma ago, when sediments eroded from the East side were deposited on the West side. This process represents the early stage of sedimentary basin formation and the opening of the South Atlantic Ocean in the region. Downward and upward movements related to heating and cooling events of these crustal blocks at different periods until recent times are proposed.     

Dynamic Faults in Random-Access-Memories: Concept, Fault Models and Tests

The ever increasing trend to reduce DPM levels of memories requires tests with very high fault coverage and low cost. This paper describes an important fault class, called dynamic faults, that cannot be ignored anymore. The dynamic fault behavior can take place in the absence of the static fault behavior, for which the conventional memory tests have been constructed. The concept of dynamic fault will be established and validated for both dynamic and static Random-Access-Memories. A systematic way to develop fault models for dynamic faults will be introduced. Further, it will be shown that conventional memory tests do not necessarily detect its dynamic faulty behavior, which has been shown to exist in real designs. The paper therefore also presents new memory tests to target the dynamic fault class.     

具有未知扰动的广义系统的故障检测

研究具有未知扰动的随机广义系统的故障检测问题,在合理的条件下,利用状态变换从原系统中分离出一个与未知扰动解耦的降阶子系统,构造了该随机子系统稳定的滤波器,给出了输出偏差量的统计特性,在此基础上,实现了系统故障的检测．     

智能网SCP的两级并发模型与软件容错研究

智能网作为一种能够快速灵活地定义与提供电信新业务的体系结构，近年来受到人们的普遍重视，其中，业务控制点ＳＣＰ作为整个系统的核心，它的可靠性与全网的服务质量息息相关。本文中，我们首先指出了目前的ＳＣＰ产品在容错性能上存在的不足，然后根据ＳＣＰ的结构和运行机制提出一种两级并发模型，并基于此模型对其软件容错的途径进行了深入的探讨与研究。本文首次提出了应用软件出错情况下保证所有在线呼叫可靠处理的容错目标，并在ＳＣＰ系统级与呼叫级两个并发层次上给出了切实可行的容错策略或算法，最后，我们还对ＳＣＰ软件有效度的估算进行了进一步讨论。