This paper is an attempt to outline the most promising methodology for quantitative anlysis of ship-borne computerized automation system found in a pilot study. Data for a cost function intended as a measure of the ship utility, are established for different failure modes of a computer system. Analysis on item level yields a cost estimate for the ship at large, as a function of the computer system reliability and availability.

This paper is an attempt to state some of the general background of reliability engineering as a part of modern system theory. It is shown how certain simple reliability analysis thechniques yield valuable information on system reliability and availability. Particular emphasis is placed on failure modes and effects analysis applied to part of a ship automation system. Further, reliability computations are performed, as an example, for some items within this system. It is shown how the analyses give valuable information related to decisions on system design and choosing between design alternatives.

Three models are presented in which stochastic simulation models are used to construct simulations of systems composed of unreliable components. The releability of the resultant systems is inferred from behavior of these simulation models.

Introduction of computers onboard ships to provide a high degree of automation necessitates calculation of computer system reliability to evaluate the utility of the system. The reliability aspect of the system is simulated by a model using Markov chains. Having defined the system state space and the transition rates, the model provides evaluation of the state probabilities. Evaluation of system utility is based on computer task values and the failure probabilities. Application of the analysis model to an existing system reveals information useful in assigning redundancy, eliminating bottle-necks and allocating spare parts.