4. Conclusion

This chapter provided some aspects to probabilistic modelling in solving analytical problems of system engineering. The main tasks of engineering design are analysis of system operation from the moment of the conception and substantiation of the initial idea to the moment of writing off and wrapping the product so that it does not fail during the service period. When solving these problems, variability in the employed materials, loads, manufacturing process, testing techniques, and application inevitably arise. Probabilistic models and probabilistic methods proceed from the fact that various uncertainties are inevitable end essential features of the nature on an engineering system or design and provide ways of dealing with quantities whose values cannot be predicted with absolute certainty. Unlike deterministic methods, probabilistic approaches address more general and more complicated situations, in which behaviour of the engineering system cannot be determined with certainty in each particular experiment or a situation. Probabilistic models enable one to establish the scope and limits of the application of deterministic theories and provide a solid basis for substantiated and goaloriented accumulation and the effective use of empirical data. Realizing the fact that probability of failure of engineering system is never zero, probabilistic methods enable one to quantitative assess the degree of uncertainty in various factors, which determine the safety of system and design on this basis a system with a low probability of failure.

Analysis of the largest man-caused and natural-technogenic catastrophes of recent years indicates the need to improve methods and means of ensuring the safety of the engineering systems. One of the main ways in this direction is to improve the historically established system of forming the scientific basis for engineering calculations of the characteristics of strength, stability, durability, reliability, survivability, and safety. Of decisive importance is the need to switch to a new methodological framework and principles for ensuring the safety of engineering systems by the criteria for risks of accidents and disasters. A special role in this direction is that security defines all the main groups of requirements for engineering systems: strength, rigidity, stability, reliability, survivability, and risk.
