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排序方式: 共有7613条查询结果,搜索用时 140 毫秒
21.
This paper deals with fault detection problems in sampled-data (SD) systems. A tool is first introduced for the analysis of intersample behavior of SD systems in the frequency domain from the viewpoint of fault detection and isolation. Based on it, a direct design approach of fault detection systems for SD systems is proposed, and further the problem of full decoupling from unknown disturbances is studied. 相似文献
22.
J Strother Moore 《Formal Aspects of Computing》1994,6(1):60-91
We present a formal model of asynchronous communication between two digital hardware devices. The model takes the form of a function in the Boyer-Moore logic. The function transforms the signal stream generated by one processor into that consumed by an independently clocked processor, given the phases and rates of the two clocks and the communications delay. The model can be used quantitatively to derive concrete performance bounds on communications at ISO protocol level 1 (physical level). We use the model to show that an 18-bit/cell biphase mark protocol reliably sends messages of arbitrary length between two processors provided the ratio of the clock rates is within 5% of unity. 相似文献
23.
本文介绍了应用模糊数学方法进行计算机辅助诊断电视机的故障原因,这种方法有效性在于建立模型的因果关系正确性和自动搜索范围及速度。 相似文献
24.
By incorporating digraph models, fault trees and fuzzy inference mechanisms in a unified framework, a novel approach for fault diagnosis is developed in this work. To relieve the on-line computation load, the fault origins considered in diagnosis are limited to the basic events in the cut sets of a given fault tree. The symptom occurrence order associated with each root cause is derived from system digraph with the qualitative simulation techniques. The implied candidate patterns are enumerated according to two proposed theorems and then encoded in the inference system with IF-THEN rules. The simulation results show that the proposed approach is not only feasible but also capable of identifying the most likely cause(s) of a hazardous event at the earliest possible time. 相似文献
25.
Helena Szczerbicka 《Performance Evaluation》1992,14(3-4):217-226
In this paper the performability analysis of fault-tolerant computer systems using a hierarchical decomposition technique is presented. A special class of queueing network (QN) models, the so-called BCMP [4], and generalized stochastic Petri nets (GSPN) [1] which are often used to separately model performance and reliability respectively, have been combined in order to preserve the best modelling features of both.
A conceptual model is decomposed into GSPN and BCMP submodels, which are solved in isolation. Then, the remaining GSPN portion of the model is aggregated with flow-equivalents of BCMP models, in order to compute performability measures. The substitutes of BCMP models are presented by means of simple GSPN constructs, thereby preserving the 1st and 2nd moments of the throughput. A simple example of a data communication system where failed transmissions are corrected, is presented. 相似文献
26.
27.
Allen M. Johnson Michael A. Schoenfelder David J. Lebold 《Quality and Reliability Engineering International》1993,9(1):55-62
The Rainbow net simulation technique is applied to modelling the impact of system load and fault handling on the availability of a fault-tolerant multiprocessor architecture. Rainbow nets are described along with the motivation for creating this modelling technique. A Rainbow net fault-handling model is created for the fault-tolerant multiprocessor architecture and the topology is shown to remain constant in size, independent of the number of processor, memory and I/O elements configured in the system. Simulation is performed with a varying load in terms of the number of active jobs the system must support. Results are given showing how the fault-tolerant capability varies with load. Two new metrics for evaluating fault tolerance are introduced; namely full fault-tolerability and partial fault-tolerability. They are based on simple observations in the model. 相似文献
28.
29.
We present the fabrication and short circuit test results of a 14 kV single-phase resistive superconducting fault current limiter (SFCL) based on YBa2Cu3O7 (YBCO) films. Individual components were processed using the 4″ YBCO films and have the rated voltage and current of 600 V and 35 A at 77 K, respectively. Twenty four components, eight components in series and three lines in parallel, make a module having the rated voltage and current of 4.8 kV and 105 A, respectively. Three modules were assembled in series to produce the SFCL working at 77 K, a 14 kV single-phase machine for the 22.9 kV Y-Y grid. short circuit tests were successfully conducted in an accredited test facility with the maximum fault currents up to 14.1 kAP. All components quenched together upon faults and shared the rated voltage evenly without any supplementary device between the modules. This proves that the SFCL based on YBCO films may not only work reliably at 22.9 kV, but also provide technical feasibility for higher voltage application including the transmission grids. 相似文献
30.
基于神经网络的模拟电路故障诊断优化近似方法 总被引:2,自引:1,他引:1
本文提出了线性电阻电路故障诊断的一种神经网络优化方法。其基本思想是应用Hopfield网络原理来处理L1范数问题,以此来进行诊断。对实例的计算证明此法是可行的。 相似文献