The subject matter of the article is the processes of synthesis of the information and telecommunication network (ITN) for solving applied problems of safety-critical systems (SCS). The goal is to develop a mathematical model for the optimal distribution of applied tasks of safety-critical systems over the ITN nodes. The tasks to be solved are: to formalize the procedure of distribution of applied tasks and SCS software over the ITN nodes; to develop a mathematical model of optimal distribution in order to minimize the cost of network resources; to select an effective algorithm for solving it. The methods used are: alternative-graph approach, mathematical optimization models, methods for solving nonlinear integer programming problems with Boolean variables. The following results were obtained: the task of selecting the ITN optimal structure was formulated according to the alternative-graph model of information processing; in addition to structural characteristics, the requirements for the parameters necessary for performing applied tasks were taken into account while constructing a mathematical model; when minimizing the cost of a computing resource, constraints related to the capabilities for financing the development and operation of the network are taken into account; the costs for organizing additional connections among the network nodes are considered as well. As a result, a mathematical model of distributing SCS applied problems over the ITN environment was obtained in order to minimize the total costs of computing resource, data transmission, network setting and maintenance. This model is a non-linear integer programming problem with Boolean variables. Taking into account the specific nature of the objective function and model constraints with the use of pseudo-Boolean functions, the original task is reduced to a linear form. The obtained model represents the canonical form of the linear optimizing problem of large-dimensional Boolean programming, for which the method of the recession vector is effective. Conclusions. The scientific novelty of the results obtained is as follows: 1) the optimization model of distributing applied tasks over the nodes of the computer network was improved by defining the objective function in order to minimize the costs of both computational and data transmission and the constraints caused by the requirements for the technical and information structure of the network; 2) methods for solving the problems of optimizing the ITN structure on the basis of models of nonlinear Boolean programming by transforming the initial task into a linear form and applying the recession vector method was further developed, which makes obtaining a quasi-optimal solution of the problem in the context of large dimension possible.

As the analysis of recent events in the East of Ukraine shows, radio communication is the transport basis for the construction of telecommunication networks of special purpose. In view of the above, the subject of study in the article are the special radio communication systems, operating in a complex electronic environment. The purpose of this article is to develop a mathematical model for the effects of interference on systems of special radio communication. The tasks solved in the course of the study: a formal description of various types of noise that is used to suppress the systems of special radio communication; analytical representation of the probability of a bit error for signals with different types of modulation under the influence of the main types of deliberate disturbances; development of recommendations for increasing the noise immunity of special radio communication systems with different types of signal modulation under the influence of deliberate interference. In the course of the study, the following methods were used: signal theory, radiocommunication theory and the theory of potential impedance protection. In the course of the study, analytical dependencies were obtained that allow us to calculate the probability of a bit error in the effect of intentional interruptions for different types of signal modulation. Conclusions: the proposed mathematical model should be used in the analytical modeling and evaluation of the performance of broadband radio networks of a special purpose taking into account the combined action of the additive white Gaussian noise and structural impediment, algorithms for the formation and processing of signals at the physical level, as well as the properties of the radio channel.model of impact interferences on radiocommunication systems for special communications