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No 6 (2025)
IN MEMORY OF A SCIENTIST
EVGENIY ALEKSANDROVICh FEDOSOV (14.05.1929 – 08.09.2025)
Journal of Computer and System Sciences International. 2025;(6):3-3
3-3
SYSTEMS THEORY AND GENERAL CONTROL THEORY
DECOMPOSITION IN THE TIME-OPTIMIZATION PROBLEM FOR A LINEAR DISCRETE-TIME SYSTEM WITH BOUNDED CONTROL
Abstract
The paper considers the solution to the time-optimization problem for a linear system with discrete time and geometric constraints on control. A method for decomposing a multidimensional system into two-dimensional subsystems to reduce time complexity and an algorithm for calculating the vertex sets of the sum of two polyhedra on a plane in explicit form have been developed. An example of using the method and algorithm to solve the problem of fastest damping of a high-rise structure located in a seismic activity zone is given.
Journal of Computer and System Sciences International. 2025;(6):4-27
4-27
OPTIMAL MANAGEMENT
SYNTHESIS OF TIME-OPTIMAL CONTROL FOR AN INVERSE LINEAR PENDULUM ON A CART
Abstract
A mechanical system is considered, which is an inverted pendulum mounted on a cart. The cart moves along a horizontal line under the action of a bounded control force. The pendulum can deflect in a vertical plane passing through this line. The dynamics of the system is studied in a linear approximation. Based on Pontryagin’s maximum principle, the problem of synthesizing the optimal speed of movement of the cart to a given point on the line with the pendulum stopping in the upper position is solved. A description of the sets in the phase space on which the control function changes sign is given, the behavior of the optimal trajectories is studied. The approach used consists of sequentially solving the problems of time-optimal control for subsystems of lower dimension.
Journal of Computer and System Sciences International. 2025;(6):28–37
28–37
OPTIMIZATION OF CONTROLLED MOTIONS OF LINEAR MECHANICAL SYSTEM
Abstract
Motions of linear mechanical systems of a certain type are studied. The problem of control design that brings such a system to a given state in a fixed time and minimizes a functional, which is quadratic in phase and control variables, is posed. The solution is sought within the framework of a generalized formulation of the problem with an integral representation of the system constitutive laws. A numerical optimization algorithm based on successive minimization of the constitutive and cost functionals is proposed. Approximation of the phase trajectory and input signals is constructed in the class of piecewise polynomial splines.
Journal of Computer and System Sciences International. 2025;(6):38–51
38–51
OPTIMAL MOVEMENT OF A PLATFORM WITH AN INVERTED PENDULUM
Abstract
We consider the problem of the optimal horizontal displacement of a platform with a pendulum over the greatest distance in a given time by means of a limited force applied to the platform. At the initial and final moments of time, the system is at rest, and in both states the pendulum is in the upper (unstable) equilibrium position. During the movement, it can pass through the lower position. There is no friction, kinematic restrictions are not imposed on the system (constructively excluded). Trajectories satisfying the necessary optimality conditions are constructed numerically. The evolution of the optimal control functions with a change in the assigned movement time is shown in a special diagram.
Journal of Computer and System Sciences International. 2025;(6):52–67
52–67
MANAGEMENT OF SYSTEMS WITH DISTRIBUTED PARAMETERS
OPTIMIZATION OF THE BLADES INDIVIDUAL CONTROL DURING HELICOPTER MAIN ROTOR SPIN-UP UNDER WIND CONDITIONS
Abstract
The article considers the problem of optimal individual control for the rotor blade during helicopter main rotor speedup in wind conditions. Movement of the blade during the main rotor speedup can be described using a system of differential equations taking into consideration its combined bending and torsional vibrations. However, performing calculations for such detailed model requires significant computational resources and time, which complicates the practical solution of optimization problem. Therefore, the mathematical model of combined bending-torsional vibrations of the rotor blade is approximated by an artificial neural network and using this approximation a search for optimal control is carried out by the nonlinear programming method. The paper provides results of numerical experiment that confirms applicability of the chosen approach to problem solution.
Journal of Computer and System Sciences International. 2025;(6):68-79
68-79
COMPUTER METHODS
CONFIGURATION-ADAPTIVE PARALLEL SOLVER FOR INTEGER PROGRAMMING PROBLEMS
Abstract
This paper presents a parallel application software package for solving integer linear programming problems. The software is developed using a Master–Worker architecture and is intended for distributed-memory systems. A key feature of the package is a configuration-oriented approach to the branch-and-cut method. Each worker process that solves a part of a single branching tree is assigned a configuration that defines a set of parameters: the cut-generation method, the branching-variable selection strategy, the order of traversing the search tree, and the presence or absence of reductions. A subset of workers is allocated to evaluate the effectiveness of existing configurations and to compile their ranking. Test results demonstrate solution scalability. A comparative analysis with similar open-source solutions is provided.
Journal of Computer and System Sciences International. 2025;(6):80-87
80-87
APPLICATION OF THE EQUIVALENCE SET METHOD TO SOLVING INVERSE MULTICRITERIAL PROBLEMS FOR DISTRIBUTED SYSTEMS WITH MANY PARAMETERS
Abstract
The application of the equivalence set method for solving inverse multicriterial problems for distributed systems with many input parameters is described. The direct problem considered as an example is described by a fourdimensional system of differential equations in partial derivatives of the second order. This hydrodynamic model has several independent adjustable parameters, the values of which are not always determined from theory or observational data when studying the corresponding processes. Therefore, it is necessary to solve the inverse problem of determining the optimal sets of values of the model parameters by several criteria. To solve this problem, the equivalence set method is used, developed for solving multicriterial problems of discrete optimization and inverse problems of mathematical physics and other sciences. An algorithm for its application is described using the example of this problem, and the results of computer calculations are given.
Journal of Computer and System Sciences International. 2025;(6):88-97
88-97
DEVELOPMENT OF ALGORITHMS FOR THE JOINT BEHAVIOUR OF AUTONOMOUS UNMANNED VEHICLES GROUP SURVEYING DEFINITE WATER AREA
Abstract
The article is devoted to the study of problem of joint behavior of autonomous unmanned vehicles group during the survey of water area. Routes of the vehicles are assumed to be known. The mathematical model of the survey process and scheduling algorithm are proposed.
Journal of Computer and System Sciences International. 2025;(6):98–107
98–107
SYSTEM ANALYSIS AND OPERATIONS RESEARCH
DYNAMIC MODELS OF TRANSPORT RESOURCES MANAGEMENT
Abstract
In modern conditions, methods of organizing transportation that allow the most rational use of available transport resources are becoming especially relevant. Taking this into account, this paper proposes models for managing urban passenger transport taking into account restrictions on existing transport capacities and passenger flow intensity. One of these models is to distribute a limited fleet of buses over a finite number of routes, while minimizing the total time lost waiting for transport service or minimizing the number of passengers whose transport service time exceeds the critical one. The article presents mathematical formulations of these problems and methods for solving them.
Journal of Computer and System Sciences International. 2025;(6):108-129
108-129
THE PROBLEM OF SHOOTING CONTROL WITH MOBILE BATTERIES
Abstract
The method of sequential modification of the objective function coefficients for transportation-type problems is extended to the modified effective firing problem, which includes additional means of engagement and a reward for not using all ammunition. A decomposition algorithm is examined in detail, which at each step, finds a so-called pseudosolution and sequentially modifies the coefficients of the objective function in such a way that the next pseudosolution coincides with a feasible optimal solution of the problem. Special attention is given to solving the problem in the degenerate case. The dependence of the algorithm’s runtime on the problem’s dimensionality is established experimentally.
Journal of Computer and System Sciences International. 2025;(6):130-134
130-134
METHOD OF SENSOR FAULT IDENTIFICATION IN LINEAR AND NONLINEAR SYSTEMS
Abstract
The problem of sensor fault identification in continuous-time and discrete-time nonlinear systems under external disturbances is studied. A solution is based on the reduced-order model of the original system. The relations allowing designing the observer of the minimal dimension producing exact or approximate estimate of sensor fault are derived. The theoretical results are illustrated by an example.
Journal of Computer and System Sciences International. 2025;(6):135–145
135–145
IMAGE RECOGNITION AND IMAGE PROCESSING
INFORMATION-THEORETIC BOUNDS TO ACCURACY FOR BIOMETRIC IDENTIFICATION IN METRIC SPACES OF DATA REPRESENTATIONS
Abstract
For both datasets of biometric objects given by images and an ensemble of the different modality datasets, the lower bounds to error probability of person identification subject to a fixed amount of information have been investigated. The bounds are constructed using a probabilistic object classification model in metric spaces of the object representations. These bounds are independent on decision algorithms and they are formed by the inverses of the rate-distortion functions for the model of discrete source coding with Hamming distortion when the source letters are transmitted over a noisy channel. The difference between a unit and any obtained lower bound to error probability produces an appropriate upper bound to accuracy of person identification depending on a given amount of processed information in a given dataset of the object representations. The obtained bounds are useful for estimating an efficiency of the decision algorithms in terms of deviations of the algorithm error probability or accuracy relative to the boundary values subject to a given average amount of information for making the decisions.
Journal of Computer and System Sciences International. 2025;(6):146–154
146–154
ROBOTICS
DYNAMICS OF THE TELESCOPIC LINK WITH ACTIVE DAMPING BASED ON THE MAGNETORHEOLOGICAL FLUID
Abstract
The simulation problem solution for the telescoping link dynamics with damping is proposed in the article. The link stiffness is a variable and is controlled by the magnetorheological fluid. The previously created models are updated. Currently, the geometrical dimensions of the top and the bottom rods are taken into account, as well as those of the cylinder, the cylinder covers, and the piston that moves inside the cylinder with magnetorheological fluid. The models also take into account their masses and the axial moments of inertia. The load at the end of the link due to its interaction with the other links of the mechanism is approximated by a uniform ball. The variation of the link mass and its moment of inertia in the process of the magnetorheological fluid movement between the two cylinder sections separated by the piston with channels has also been taken into consideration. The proposed clarifications improve the compliance degree of the mechanical model to the actual technical device. The functional and control models of the proposed telescopic link with damping for the new generation exoskeletons with enhanced comfort are described. The solutions of the direct and inverse dynamics problems are presented.
Journal of Computer and System Sciences International. 2025;(6):155-172
155-172