The article considers some vital cybersecurity issues regarding industrial control. Proposing more realistic confidentiality, integrity, and availability (CIA) triad, the article advocates availability as the significant property for industrial automation and control systems (IACS) and the associated problem of availability assessment to be the most urgent. The challenges arising during the IACS availability assessment are highlighted. The results of the analysis of availability interpretations in international regulatory documents are presented; the IEC 62443 definition is proved to be the most appropriate for the quantitative availability assessment. The availability reference model with such domains as Time-dependent parameters, Delay, Platform, System, Function, and Availability metric is proposed. Using this model, the availability metric based on the time of fulfillment of IACS functions, or delay, as a measure is derived, and the technique for its calculation according to the system domain is discussed as well.

A simplified model of democratic voting in society was considered. Society consists of people combined in a social graph. Two people are connected by an edge if they communicate with each other. Each person initially has his or her own intention about voting: will he or she vote "for" or "against". However, people tend to pay attention to the opinions of those around them with whom they interact. A person tends to vote the way most of his acquaintances think, even if their prevailing opinion does not coincide with his opinion. Of interest are such distributions of opinions on graphs in which voting is successful, but the number of people who initially intend to vote "for" is minimal (so called positive vertices). Such cases are referred to here as optimal cases. For arbitrary graphs, the optimal case is achieved with only two positive vertices to which all other vertices are connected. This is interpreted as the fact that democratic voting does not decide in favor of the majority in the general case. However, such an optimal social graph is rarely found in general practice case. In practice, a social graph consists of a large number of vertices with a relatively small degree in each. Then we considered the graphs with the restriction on the vertex degree from above. An empirical formula expressing the optimal value of positive vertices was obtained, and the graph on which the optimal case is reached was also obtained. It turns out that the more the vertex degree constraint from above, the less the optimal number of positive vertices. The difference between the optimal number of positive vertices in regular graphs and almost regular graphs in which the degree of a vertex can take two adjacent values is also considered. Numerical experiments have shown that the optimal value of positive vertices in both graphs with the same number of vertices and close constraints on the degree of a vertex coincides in all cases except two exceptions of special kind.

The aim of the work is a comparative analysis of investment portfolios built based on stochastic modeling. We obtained actual stock price data of 80 Russian companies traded on the Moscow Stock Exchange for the last six years. Using it, we created simulation models.

Precision agriculture makes use of high-accuracy navigation, attitude determination, and obstacle detection methods to save resources and to obtain better results. The collected robot position and attitude, and obstacle location data can be effectively employed to synthesize control algorithms for autonomous agricultural machines. These algorithms are applied for coverage path planning, route planning, motion stabilization along the specified paths, obstacle avoidance, and ensuring guaranteed behavior. These tasks are considered in the paper.

Little is known about seismic activity of Venus and location of seismic sources. There are no seismic instruments that would be able to survive over extended periods under Venus conditions. Nevertheless, a seismic experiment is planned on the surface of Venus. It is also proposed to register disturbances in the atmosphere and ionosphere of the planet caused by seismic events. For forthcoming seismic experiments on Venus, it is important to know in which areas the stresses are large enough and capable of producing venusquakes. Here we study stress field of Venus starting from a simple model: a liquid core and an elastic mantle and crust with the help of a static method.