Nº 5 (2025)

Various variants of selectively invariant systems have been developed by dividing the complete disturbance model into individual components and placing them in the structures of regulators of mutually subordinate control loops, configured for different response speeds. Mathematical representations of regulators containing various disturbance models were obtained using modal and polynomial synthesis methods and using symbolic computing tools. A comparative study of systems was conducted according to specified quality indicators, degree of complexity and adaptation capabilities to speed changes. The software implementation of adaptive regulators has been completed and a comparative analysis of the efficiency of adaptive systems with speed variations has been made. The structure of the system has been revealed, which provides more complete compensation of the three-component harmonic disturbance.

The problem of comparing estimates of aerodynamic coefficients calculated from flight data with similar coefficients from the aerodynamic characteristics bank is investigated. A method for calculating optimal estimates of coefficients closest to the purge data is proposed, and its properties are established. The method has been tested on short-range aircraft flight data in longitudinal motion. A good mutual correspondence of flight and purge coefficients is shown.

The article considers the motion of the controlled object, which performs a high-speed maneuver in a plane with constant thrust. The purpose of the maneuver is to maximize the velocity of movement along a given straight line in a finite specified time. The linear tangent law is used as a control law. The limiting form of the function is determined as a cubic polynomial for the lateral projection of the coordinate and a quadratic polynomial for the lateral projection of the velocity at infinitely large thrust, the asymptotic behavior of the integration constants is analyzed. Numerical modeling is performed for the corresponding functions, alternative suboptimal controls are proposed.

In the proposed paper, the author solve the problem of synthesis self-checking discrete devices with concurrent error-detection circuit based on the Boolean signal correction using constant-weight “1-out-of-3” code. In this case, the diagnostic object outputs are divided into groups of three each and separate concurrent error-detection subcircuits are organized according to the “1-out-of-3” code. Then, the control signals are compressed based on the pyramidal connection of the two-rail signal compression modules. The peculiarity of the approach used is the transformation of signals from all three outputs from the controlled group in the concurrent error-detection circuit, against two as was assumed in earlier studies. This approach allows to obtain more than six thousand variants of the concurrent error-detection circuit organization, in contrast to the previously known two. The paper presents a technique for obtaining a functional relationship between the output values of the correction function calculation unit and the diagnostic object. Expressions for calculating the signal correction functions are compiled considering the need to generate tests for all conversion gates and the “1-out-of-3” code checker. Such dependence significantly simplifies the procedure of self-checking device synthesis. In the paper, as an example, such a dependence between the values at the block outputs for calculating the correction functions and the diagnostic object is established, which makes it possible to calculate the correction function of two outputs in the controlled group at once, and this simplifies the block for calculating the correction function values. An example of the concurrent error-detection circuit synthesis according to the method proposed in the paper is given. This paper presents some experimental evidence of the proposed method effectiveness for synthesizing self-checking discrete devices. The results obtained in this study can be effectively used in practice in the development and design of self-checking discrete devices on various elements.

The paper considers the problem of finding the number of dominant voters in two-level voting procedures. At the first stage, voting is conducted among local groups of voters, and at the second stage, the results are aggregated to form a final decision. The goal is to determine the minimum proportion of voters supporting a proposal for it to be accepted. The paper uses the method of pairwise comparisons to analyze the structure of the problem and develop heuristic algorithms with guaranteed accuracy. Special cases are considered, including the agent communication graph as a tree, complete graph, or regular graph with an odd number of vertices. New heuristic algorithms are proposed for each case, along with pairwise comparison functions to estimate the accuracy of the solution. Results extend the use of polynomial algorithms to a broader class of problems, providing criteria for selecting the optimal algorithm during the post-processing stage.

The kinematic model of the “Dubins car” is investigated. Unlike the canonical case, the control (angular turning velocity) is constrained not by a geometric constraint on instantaneous values, but by an integral quadratic constraint, characterizing energy costs. The problem of constructing a two-dimensional reachable set in the plane of motion is posed. The solution uses Pontryagin maximum principle and the theory of elliptic integrals, as well as Jacobi elliptic functions. It is proved that controls leading to the boundary of the reachable set change their sign no more than once. A parametric description of the curves constituting the boundary of the set under study is given. The results of numerical modeling are presented and a comparison is made with the known results of constructing the reachable set under a geometric constraint on control.

The problem of fault estimation in nonlinear dynamic systems under the external disturbances is studied. To solve the problem, the methods of optimal control based on transformation of the original system into the reducing model sensitive to the faults and insensitive to the disturbances. Unlike sliding mode observers which traditionally are used to solve this problem, the suggested approach allows dispense without high frequency switching. The developed theory is illustrated by the example.

Modern recommender systems increasingly go beyond classical personalization tasks, addressing more complex scenarios of interactions between items. One such challenge is generating complementary recommendations, where standard user-centric architectures often lack sufficient flexibility. This study compares two matrix factorization-based approaches to solving this problem: a classical model trained on the user–item matrix with additional constraints derived from co-occurrence statistics, and a direct factorization of an item–item matrix constructed using a temporal co-action rule. The paper analyzes ways to overcome the limitations of traditional methods and outlines the potential of new strategies across various data types and business applications.

The problem of increasing the uniformity of electroplating by creating a concept of combined control of the electrochemical process is considered. A feature of the technological process of electroplating is that optimal control of them is possible using various control actions. At the first stage of the developed concept, the problem of designing an electrochemical process control system using a single control action is solved. At the second stage, using a combination of several control actions. At the third stage, a management system is designed based on the best results of solving optimization problems at the first and second stages.

Progressive motions of a rigid body containing an internal mobile mass and controlled by the force of its interaction with this mass are considered. The body moves within a fluid, its resistance force is proportional to the squared velocity of the body and depends on the direction of motion. The corresponding trajectories are obtained, it is shown that they approach periodic motions. The average speed of the system depending on its parameters is evaluated.