Reliability and Safety of Structure-Complex Systems

Reliability and Safety of Structure-Complex Systems

Igor A. Ryabinin"Politekhnika" PublishersSt. Petersburg2000248 pp, in Russian,ISBN 5-7325-0549-0

Author of the book defines a structure-complex system as the system mathematical descriptions of which could not be reduced to a serial,parallel or tree-like systems; behaviour of the structure-complex system is described via irregular graphs or networks. Such definition looks too general if not ambiguous, so we can simply say that this monograph deals with safety and reliability of electronic, control, communication and electric-energy-supply networks. These problems are solved in the monograph using logic and probabilistic models, Boolean differences, transformation of logic functions into probabilistic functions and some statistical methods.

In the 1st chapter the author provides examples of real life complex systems. Namely, he exemplifies logic-theoretic constructions with a principal scheme for generation and distribution of electricity onboard of nuclear power ship"Lenin". The notions of reliability, fault-tolerance, danger, apprehension,safety, dependability and survivability are defined there after that. The 2nd chapter starts with a historical, mainly Russiaoriented, tour in 1ogic-probabilistic methods: from Boole to Porecki and Bernstein to Pospelov,Makarov and Merekin. An introduction to algebra, logic and probability theory closes the chapter. A pre-processing of field data is discussed in the 3rd chapter. This deals with reliability indexes, confidence intervals for probability of refusal, admissible intervals, checking of hypothesis. Properly logic and algebraic methods are tackled in the chapters 4, 5 and 6.

Analytical and graphical representations of system's reliability and danger states are introduced in the 4th chapter. Functional networks and their structural analysis are of great concern there. A Boolean differences are characterised in the chapter using Euler diagrams. The chapter 5 defines probabilistic functions and shows how logical functions are transformed into probabilistic ones. Cut algorithm, orthogonalisation algorithm, recurrent algorithm, algorithm of path growing and circuit-logical methods are applied to produce the transformations.

Relation of a system and its elements is a subject of the 6th chapter. It focuses mainly on how to calculate correct weights for system elements, when mathematical model is designed. An element weight is acquired from a structural importance of an element, inputs of the element in the system's functioning. Sometimes co-operative contributions and injuries of several elements are also taken into account. After that author considers accuracy and trustworthiness of reliability estimates on several examples. Reliabilities of a system with three elements and a system with ring structures are mathematically analysed.

An average reader, not fixed on particulars of the algebra-of-logic techniques, will find the 7th chapter of the book most interesting because the chapter is full of live examples. Thus, for example, a danger of explosion and subsequent sinking of a submarine is mathematically modelled in functions of Boolean logic. A genesis of accidental explosions in Russian artillery ammunition stores, 1995–1998, is tackled in full details. These examples are followed by assessments of railway safety, modelling a risk of defeat by electric current, and risks in modern business enterprises.

In one of book's appendices a reader finds quite a useful summary of basic concepts of the safety theory: dangerous and safe states, damage, accident,catastrophe, failure, subjective factors, task priorities and many more. There each concept is defined and briefly discussed from theoretical and applied points of view.

The book is undoubtedly gives an original, however geographically local, view on reliability and safety with a focus on structure-related issues. The monograph may be also seen as a collateral development of mathematical methods for reliability analysis, derived from the classical works, e.g. Abernethy's compendium (2000); engineering safety issues edited by Blockley (1992); analysis of methods and approaches in safety- critical systems by Redmill and Anderson(1993); and Tait and Cox's management of risk (1998).

Andrew AdamatzkyIntelligent Autonomous Systems Lab, University of the West of England, Bristol, E-mail: adamatzky@uwe.ac.uk