Teoriâ i sistemy upravleniâ

The problem of rapprochement of a tether system with an uncontrolled space object (space debris, cargo, etc.) in an almost circular near-Earth orbit is considered. The approach method is proposed, which consists in preliminary transfer of an active spacecraft to an orbit, the parameters of which are selected so that in its relative motion it moves along a trajectory close to an ellipse relative to a passive space object. Next, the tether system is deployed with a gripper device in the radial direction, and the length of the tether approximately corresponds to half of the small semi-axis of the ellipse of relative motion. After the end of the tether deployment, the entire system continues to rotate around the passive space object. In this case, there is a possibility of additional correction of the length of the tether in order to reduce the minimum distance between the gripper device and the load. To control the movement of an active spacecraft, jet engines are used, the components of the continuous thrust of which are directed along the transversal and binormal orbits. The results of end-to-end modeling in a geocentric fixed coordinate system of the considered stages of pointing the gripper device at a passive space object in the spatial case are presented, including an assessment of the impact of the gripper process on the subsequent movement of the entire system with cargo during its transportation.

A constructive technology for solving problems of dual-channel control of two heterogeneous systems interconnected by boundary conditions with distributed parameters in linear-quadratic optimization problems by the criterion of energy saving is proposed. The resulting spatial distribution of controlled variables is approximated with given uniform accuracy to the desired state. The developed technique initially employs a procedure of parameterization of the desired control actions on a finite-dimensional subset of an infinite number of final values of conjugate variables. Subsequent procedure is applied for exact reduction to a parametric problem of semi-infinite optimization, which is solved according to the scheme of the previously proposed alternance method, which has been generalized to the situation under study. It is demonstrated that the equations of optimal controllers with lumped control actions for each of the objects are reduced to linear feedback algorithms on the measured state with non-stationary transfer coefficients. An illustrative example of optimization of the process of induction heating of two unbounded plates under conditions of ideal thermal contact on their boundary surfaces is presented, which is of independent interest.

The paper explores the possibilities of using weight-based Bose–Lin codes in the synthesis of concurrent error-detection circuit based on Boolean signals correction. The dependences of the number of weighing options in the construction of the considered class of codes on the number m of data symbols are established. It is shown that with an increase in the value of the number m, the number of weighing methods increases significantly, which makes it possible to build a large number of codes and, as a result, have greater variability in the construction of a self-checking device. The patterns that appear when the number of data symbols changes are established, linking the number of weighing options when building the code. It is shown that the number of ways to synthesize concurrent error-detection circuits based on Boolean signals correction using weight-based Bose–Lin codes factorially depends on the number of allocated data symbols among the data signals of the diagnostic object. The examples given in the paper demonstrate the effectiveness of using weight-based Bose–Lin codes in the synthesis of concurrent error-detection circuit compared to using the traditional method based on duplication. It is advisable to take the results of the study into account when developing self-checking digital devices, as well as when developing their computer-aided design systems.

An approach to the correct supervised classification problem based on the application of logical data analysis methods is considered. The description of the operation scheme of logical classifier models aimed at constructing special fragments of precedent descriptions, called correct elementary classifiers, is provided. More complex models, namely models of logical correctors, are based on the synthesis of families of correct sets of elementary classifiers. Unlike classical models, logical correctors show good results in the case of multivalued features, i.e. features with a large number of different values. The article examines issues related to reducing time costs and improving the quality of classification of logical correctors. New deterministic and stochastic variants of such models are proposed, designed to work with partially ordered data. The results of experiments on model and real data are presented.

The problem of finding rational solutions to a multi-extremal parametric problem using the ant colony method is considered. Rational solutions are solutions that are close to the optimal one in terms of the value of the objective function, but are not necessarily such. To solve for a multi-extreme problem, a modification of the ant colony method is proposed, which does not converge to a single solution, but continues to search for a solution. The ant colony method underlying the modification allows one to consider all rational solutions at the earliest iterations. The lack of convergence to a single solution solves the problem of stagnation of the proposed algorithm of the ant colony method. The solutions considered are stored in a hash table, which allows avoiding recalculation of the value of the objective function for a given solution on the computer and searching for a new solution for each agent. A new formula for determining the probability of the ant’s (agent’s) transition to a new parameter. The purpose of this formula is to solve the problem of algorithm stagnation in early iterations by increasing the probability of the agent visiting components of solutions that have not yet been considered. The algorithm of this modification of the ant colony method allows solving discrete parametric problems, determining rational values of parameters from discrete set. The paper investigates the dependence of the efficiency of the method on the parameters of the proposed modification of the ant colony method. The study on test problems and large-scale problems showed the dependence on the parameters of the additive convolution and the evaporation coefficient, which is responsible for reducing the weights obtained in previous iterations.

The conceptual phase of aircraft design is characterized by a significant degree of uncertainty in the initial data. This is largely due to the presence of random processes and incomplete information, requiring the use of non-deterministic parameters that cannot be defined by a precise number. These non-deterministic parameters are linked to parametric uncertainty, which is a key factor contributing to the increased risk of design errors. To address this challenge, this paper presents optimization models that formalize the tasks of parametric synthesis in aircraft conceptual design, with a focus on ensuring the reliability of design decisions. Probability theory and uncertainty theory are employed to represent non-deterministic parameters. The theory of uncertainty provides decision-makers with a powerful tool for constructing optimization models that encapsulate the formalized requirements of the designed system.

The article is devoted to the problems of intellectual support for the aircraft crew in a situation when, in the process of performing a flight task by the crew, a conflict arises “The stage of the flight task being performed is an immediate threat to its fulfillment”. Onboard intelligent tactical-level systems provide the crew with intelligent support in this situation. They identify an immediate threat among the observed potential threats (fix a collision), recommend to the crew a way to counter this threat (solve the task of operational goal setting that occurs to the crew when a collision occurs), recommend to the crew the details of this method. One of these systems is presented, implemented in the form of an on-board operationally advising expert system for the final phases of aircraft landing BOSES-P. Its demonstration sample, adapted to the on-board information environment of the MS-21 aircraft, successfully passed research tests with a professional pilot at the MS-21 semi-natural modeling stand at the GosNIIAS FAA.

Coreference is a task in the field of natural language processing aimed at linking words and phrases in a text that point to the same extra-linguistic object or referent. It is applicable in text summarization, question answering, information retrieval and dialog systems. In this paper, existing methods for solving the co-referencing problem are dissected and a method based on the application of a two-stage machine learning model is proposed. The language model converts text tokens into vector representations. Then, for each pair of tokens, based on their vector representations, an estimate of the probability of finding these tokens either in one name group or in two coreference name groups is computed. Thus, the method simultaneously searches for name groups and predicts the coreference relation between them.

We consider the problem of aircraft motion control under uncertainties caused by incomplete and inaccurate knowledge of the aircraft characteristics, as well as by abnormal situations in flight that affect the properties of the aircraft as a control object. One of the effective tools for solving problems of this kind, providing the adjustment of aircraft control algorithms taking into account its changed dynamics, is reinforcement learning in the variant of Approximate Dynamic Programming (ADP), in combination with artificial neural networks. In the last decade, a family of methods known as Adaptive Critic Design (ACD) has been actively developed within the ADP approach to control the behavior of complex dynamical systems. The paper discusses the application of one variant of the ACD approach, namely SNAC (Single Network Adaptive Critic) and its development through combined use with the dynamic inversion method. This approach makes it possible to form an optimal adaptive control law for aircraft motion. Its effectiveness is demonstrated on the example of longitudinal motion control for supersonic transport airplane (SST).