DEVELOPMENT OF STOCHASTIC MODELS FOR OCCUPATIONAL HAZARDS RISK ASSESSMENT

Introduction. The main disadvantage of existing methods and models of risk assessment in the field of occupational safety is the failure to take into account the dynamic characteristics of the processes of random hybrid impact on the em-ployee of hazardous and harmful production factors. Such negative impact characteristics are observed during the opera-tion of any real "man-machine-environment" system, therefore, it is imperative to take into account the risk assessment.Purpose. Development of stochastic models for assessing the risks of occupational hazards in the systems of "man-machine-environment".Methods In the development of stochastic models for assessing the risks of occupational hazards, the theory of Markov processes was used, while the boundary problem was solved - the method of the Erlang fictitious phases. Results. To find the limiting probability distribution of the random process of occupational dangers origin in sys-tems "man-machine-environment", a system of differential equations in partial derivatives and corresponding limiting78 Вісник ЛДУБЖД, №19, 2019 conditions was derived, which made it possible to determine the following basic indicators for risks evaluation of oc-cupational dangers origin:– the probability of exceeding the normalized (hygiene standards) accumulation of negative influence of the harm-ful production factor;– the probability that the effects of the negative influence on the employee of the harmful factor will be completely absent at a random period;– the probability of employment injury by an employee at a random period;– the average level of accumulation in employee of negative influence against the harmful production factor, etc.It is emphasized that such indicators can be used as criteria, provided that approach of risks evaluation will be im-plemented at the state level. A method of solving the limited problem for a system of differential equations based on Laplace transformation for the case of the Erlang distribution of working and non-working periods is proposed. Conclusions. Stochastic models for risk assessment in "human-machine-environment" systems are developed, which allow to estimate the level of risk of occupational hazards according to the basic indicators characterizing the level of occupational safety. A method of solving the boundary value problem for a system of differential equations based on Laplace transformation for the case of the Erlang distribution of working and non-working time periods is developed. The obtained solution allows to find the moments of probabilistic distribution of the level of accumulation of negative influence from the action of harmful production factors in the body of the worker. hat gives the possibility of using Chebyshev's inequality to give a lower estimate of the probability of exceeding the level of the indicated nega-tive influence of the maximum - admissible (normalized) values. In the future, the practical interest is the consideration of a random process for cases of serious injury, when the employee needs a long time to undergo treatment and rehabili-tation from the consequences of injuries received during the failure of production equipment of the second type. This problem is solved within the framework of the proposed approach and presented in the study.