Identifying the Signs of Malicious Activity in the Infrastructure of Industrial Automation Systems Using the Dominance Relation of Elements of Fuzzy Sets

The issues of using the dominance relation of elements of fuzzy sets for identifying signs of malicious activity in the infrastructure of industrial automation systems of the “Smart Factory” are considered. This approach allows us to formally describe the dominant relationships of observed and measured signs of such suspicious activity. The degree of dominance and the search for the relationship of dominance of some signs over others are determined on the basis of mathematically correct processing of the membership functions of these vaguely defined signs. These signs characterize the degree of their manifestation (activity) and the level of their importance from the point of view of the danger of ignoring them for the Smart Factory. The results of such identification will help determine the degree of danger of specific events of malicious activity and will increase the reliability of the description of security incidents. The results of experimental calculations are described. They allow, as an example, to judge the practical applicability of the proposed mathematical mechanisms for calculating the dominance ratio of elements of fuzzy sets, characterizing the degree of presence of specific signs of malicious activity, taking into account the uncertainty (fuzziness) of the source data and expert opinions, measurement data and observations.