Today in Ukraine there is an increased level of natural and technogenic threats and fire hazards. Therefore, an important task in identifying and assessing risks and threats is to determine fixed and variable factors that affect the potential for fires and to classify them by the available features. To solve the problem of classifying numerous factors of fires, we suggest using the method of building decision trees, which is a method of presenting rules in a hierarchical consistent structure where each object corresponds to a single node through which the decision is made. The use of the C4.5 algorithm helps build a branched decision tree and classify factors of fire danger. Three main classes of permanent environmental factors have been distinguished, which include land cover, topography, and climatic resources; the variable factors are the indices NDVI, DMP, and SWI. They, in turn, are divided into subclasses. The calculated weights can be used for simulating a fire hazard. The obtained values range from 0 to 1, where a value of 0 prevents natural fires (e. g., water surfaces), but values close to 1 indicate a high hazard potential of natural fires.The decision trees, obtained in the process of classification, are important for planning measures to prevent natural fires. They can also be used for zoning in terms of fire hazards in spatial modeling of fires, mathematical modeling of their effects, as well as in further monitoring and prediction of natural fires.

A concept targeting information technology is considered. The model of selection of the optimal amount of advertising on various Internet resources, in order to maximize the desired reach to the target audience is analyzed which. This model is different from traditional. A chance constrained target programming model was developed after considering the parameter that corresponds to reach for different media as random variables. The random variables in this case has been considered as the values with known mean and standard deviation. The reachability parameter can be determined by finding the ideal solution and the law on which the parameter values change. The method of multicriteria optimization is examined with determination of resulting objective function, which allows to consider various aspects of the problems of media choice and optimal budgeting and budget allocation simultaneously to get a satisfactory solution of the problem.

The comprehensive system of information security of an enterprise includes both tactical aspects of information and strategic priorities, reflecting the information policy and information strategy of the enterprise. Ensuring a given level of cybersecurity requires the identification of threat actors, their purpose, intentions of attacks on the IT infrastructure, and weak points of the enterprise’s information security. To achieve these goals, enterprises need new information security solutions. In this work, a mathematical model of the process of cyber risk management in the enterprise, which is based on the distribution of piecewise continuous analytical approximating functions of cyber attacks in the Fourier series, is obtained. A constant continuous monitoring and conduction of cyber regulatory control of the enterprise on time makes it possible to effectively ensure the cybersecurity of the enterprise in real time—predicting the emergence of cyber threats to some extent—which, in turn, determines the management of cyber risks arising in the field of information security of the enterprise. Such a Fourier series expansion of the piecewise continuous analytical approximating function of the intensity of cyber attacks on damage to standard software, obtained by approximating empirical–statistical slices of the intensity of cyber attacks on damage to standard software for each time period by analytical functions, opens up new mathematical possibilities of transition to systems of regulatory control of cyber threats of the enterprise from discrete to continuous automated process for such types of control.

Research objective. Development of algorithms that allow to implement the synthesis of a functionally stable wireless sensor network. Subject of research. Wireless sensor networks, algorithms for the synthesis of a functionally stable network. Research method. Algorithmic and numerical analysis of the procedures for performing the synthesis of functionally stable sensor networks. Research results. Ensuring the property of functional stability of a wireless sensor network provides a solution to the problem of the influence of destabilizing factors, such as: software and hardware failures, errors, accidental or intentional damage to individual structural elements, their aggregates, communication channels between them, cyberattacks, service failures, etc. Research of existing scientifically based approaches to ensuring the functional stability of wireless sensor networks and its components shows that there is no single general approach to determining the functional stability of a wireless sensor network. Therefore, the work is devoted to solving the current scientific problem of developing an algorithm for searching for the optimal structure of a wireless sensor network. An algorithm for finding a lower bound for the number of removed vertices and an algorithm for finding a lower bound for the number of removed vertices taking into account redundant communication lines have been developed. It has been established that first of all it is necessary to determine the complete set of minimal graph sections and their power. An algorithm for finding the optimal structure of a wireless sensor network has been developed, which consists of nine steps and can be used to synthesize the structure of wireless sensor networks that have the ability to self-organize in order to find its optimal structure. It is shown that the proposed algorithm has a high level of convergence and provides the desired result for a finite number of iterations, which is much better than finite search. The developed algorithm is effective when the dimension of the problem is . The results of solving test problems fully confirm the effectiveness of the algorithm in comparison with the results of the solution by exhaustive search, which confirms the importance of the results obtained. This result can be applied to information systems for production process control and information security systems that have a wireless topology and are under the influence of external and internal destabilizing factors of an impulse nature. The proposed algorithm actually implements the controllability conditions in such a system through monitoring the state of the system and mechanisms for restoring functioning in its optimal perimeter.