Iraj E. Methods and information technology of the high-availability informational-controlling systems analysis and failures criticality reduction

The object of research is processes of development, reengineering and maintenance of high availability distributed informational-controlling systems (ICS). The research objective is reliability and safety increasing of the high-availability distributed ICS by developing of table-probabilistic methods and informational technology of failure criticality analysis and reduction. Basic research methods are: methods of graph and set theories, and Boolean algebra; methods of system analysis and theory of optimization; methods of probability theory and theory of Markovian processes with continuous time and discrete states. Scientific significance of results is defined by the fact that they has enhanced table-probabilistic methods of development, reliability and safety assessment and ensuring of the high-availability distributed ICS. Practical significance consists in developing and enhancing of engineering techniques of ICS reliability (availability) and safety assessment and ensuring and tools developing forICS reengineering and its failure criticality analysis. These results form an applied information technology, allowing to automate decision-making processes at reliability and safety requirements justification and maintenance parameters analysis and choice for high-availability distributed ICS. It also allows increasing of ICS reliability and safety by reduction of probability of announced and hidden failures in 1.4 - 1.7 times as well as critical failure rate reduction down to acceptable level. For the first time the method of the ICS reliability and safety ensuring by using multidimensional criticality matrix which, unlike existing ones, is based on procedures of discrete optimization choice of fault tolerance and recovery means from the limited set of possible variants in a "probability, severity and recovery time" parameter space with the discrete space has been developed. It allows to minimize probability of critical failures occurrence. The method of critical failure analysis for the hierarchical ICS using FMEA-tables to enhance the confidence of reliability and safety measures at different system life-cycle stages has been improved. Markov models of ICS's computer systems reliability allowing to extend and to analyze set of maintenance policy as well as to increase system availability have received the further development. Application - branch. Further use of the results received in the dissertation is recommended in the organizations that develop distributed ICS of aerospace and energy complexes as well as perform their expertise and verification.