Accession Number:

ADA199940

Title:

Approximate Evaluation of Reliability and Availability Via Perturbation Analysis

Descriptive Note:

Final rept. Jun 1984-Sep 1987

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE

Report Date:

1988-03-01

Pagination or Media Count:

131.0

Abstract:

The progress on a three-year effort to examine approximate reliability evaluation techniques for fault tolerant control and sensor system is described. The motivation for the work is provided by the fact that the reliability models for these system tend to be finite state semi-Markov models with large dimension that evolve relatively slowly in time due to the rare occurrence rate of component failures. The transient behavior of these models is of interest because the steady state behavior is trivial and not of practical importance. The evaluation of the transient behavior of such models, however, is intractable even for relatively simple system architectures because of the widely varying rates at which events occur in the model. The research effort concentrates on generating useful limit theorems that approximate the behavior of these models asymptotically well as the small component failure rates become vanishingly small. Using the work of Korolyuk as a starting point, such limit theorems are generated for both continuous and discrete time models that are representative of fault tolerant system behavior. In particular, the limit theorems of Korolyuk are expanded to cover models where the classes of the decomposed models include trapping states when the small parameter vanishes and to cover models where the holding times are not necessarily scaled by the small parameter.

Subject Categories:

  • Computer Systems

Distribution Statement:

APPROVED FOR PUBLIC RELEASE