Objective. The article deals with heat removal from computer processors in order to provide the necessary thermal conditions and temperature control of heat-generating components on integrated circuits. Methods. Methods for modeling heat exchange processes during heat transfer from a heated integral crystal to the environment are applied. Results. The power efficiency of heat rejection processors increases when using radiating thermoelectric semiconductor devices since heat is absorbed in some junctions, and instead of generating heat photons of the ultraviolet range are emitted to obtain better energy characteristics to ensure the necessary power removal from the heatgenerating components of radio-electronic circuits. This approach has a significant advantage as radiation has the maximum speed when transferring energy compared to convection and conduction, which allows for non-inertial heat removal from heat-generating components to the environment. This approach also allows increasing the efficiency of the cooling system and accelerating the transfer of heat from the heated areas to prevent heat breakdown. Conclusion. The conducted research allows concluding that light-emitting thermoelectric semiconductor devices can be used for cooling with high power efficiency, which can transfer large amounts of power to the environment with low inertia. An innovative cooling system for computer processors allows increasing the degree of integration by several orders of magnitude, which will increase the performance of computers and their speed.

Objective. The article deals with aspects of modeling the working processes occurring in marine thrusters of amphibious vehicles, taking into account the specifics of their operation. Methods. The methods of 3D modeling of propellers in CAD and CAE packages are applied, which can determine and optimize the parameters of ongoing work processes with reliable accuracy. Results. A mathematical construct is proposed that allows calculating the characteristics of marine thrusters of amphibious vehicles. The propeller is designed to provide more thrust compared to the original design, making it possible to increase the speed of movement on the water and reduce the radius of circulation when moving through the water. The calculated version of the propeller provides an increase in thrust by 36%, allows developing a high speed on the water, and significantly reduces the radius of circulation of the ferry-bridge machine when maneuvering on the water. Conclusion. The proposed option for increasing the speed and maneuverability of ferry vehicles on the water is the most effective and least expensive; a promising direction for further research to achieve maximum efficiency is the creation and verification of software, hardware, and methodological complexes for modeling the joint operation of the "marine thruster - hull - power plant" system.

Objective. General cryotherapy effect on the human body with cooling gas is a physiotherapy method, the positive effect of which has been proven for more than 40 years of use (including in Russia, which is one of the leaders in this field). The objective of the study was to assess the prospects for the development of technical support for cryomedical effects on human organs. Methods. The work presents an overview and analysis of the current state of the technical support of this cryomethod. Results. The prospects for the method development and directions for improving the equipment are shown. It is noted that the development of the method is limited primarily by the lack of accuracy of cryotherapy and relatively high cost. Conclusion. Low-temperature therapeutic equipment can potentially be located not only in medical, cosmetology, sports facilities but also in office centers. The key in this direction is the development of technical support capabilities, which will further allow practitioners to impulse the development of methods for applying cryotherapy with cooling gas in the mass use of this physical factor in medicine.

Objective. The article offers a three-stage model that allows increasing the effectiveness of authentication in the implementation of distance learning systems, not only in automatic proctoring systems but also in complex information systems of critical objects. Methods. Increasing the effectiveness of user authentication is achieved by increasing the accuracy of authentication using keyboarding. Results. The proposed model will help to implement the process of access differentiation for fraudsters and legal users, by adapting to the slightest changes in the keyboarding parameters, which allows increasing the authentication accuracy. During testing, one of the tested users was authenticated using a deviation comparison, while the other three users were authenticated using the χ² criterion. The remaining users were not able to complete the authentication procedure at all stages of the system. Conclusion. The results of an experimental study showed the high ability of the proposed model of access control for legitimate users and attackers with some minor changes in the parameters of the keystrokes dynamics, improving the accuracy of user authentication. The user authentication reliability in practice was 97.5%.

Objective. The process of designing a long-range aircraft, in particular at the preliminary design stage, involves comparing and analyzing a large number of design alternatives with specified performance criteria. At the same time, the problem of choosing the composition of rational design parameters is solved, which is an actual problem of the preliminary design stage of a long-range aircraft. Methods. The developed method allows determining the vector of parameters that provides rational characteristics for a given efficiency criterion. In this regard, the authors propose to introduce a global efficiency criterion - the takeoff weight of the long-range aircraft, and the specific criteria are the aerodynamic quality in cruise and the value of fuel efficiency. Results. In this formulation of the design problem, it is necessary to solve several interrelated problems, some of which are formalized, while others do not yet have a mathematical construct and software that allows automating the process. A distinctive feature of the proposed approach to finding a rational design solution is the use of statistical analysis methods in combination with methods of high-precision mathematical modeling, software-implemented in a single information environment using the Fortran V and C++ languages. Conclusion. The proposed method for selecting the composition of rational design parameters allows forming the appearance and providing the specified characteristics for its component elements at the early stages and stages of designing the long-range aircraft.

Objective. The purpose of this work is to develop the concept of a system for monitoring the state of infrastructure facilities using 3D laser scanning technology and processing the obtained data using specialized software. Methods. The primary methods used in this study are the analytical method, which consists in reviewing and system analysis of existing methods for monitoring buildings and structures and developing a technological scheme for monitoring infrastructure objects based on them, the method of empirical system analysis, and the instrumental method presented by conducting field surveys in the framework of periodic strain geodetic monitoring using a Leica ScanStation C10 ground laser scanner to obtain initial spatial information. The object of research is an artificial road transport structure in Krasnodar (Turgenevsky bridge). The subject of the study is the feasibility of using periodic strain geodetic monitoring and the system monitoring the state of infrastructure facilities. Results. The research result is the development of a concept for a system for the periodic state monitoring of infrastructure facilities with the identification of the nature and degree of strain processes occurring in them during operation, based on the use of 3D ground laser scanning technology. Conclusion. The use of a ground laser scanning system, due to its speed and high accuracy, provides the complete information about the control of the nature and types of strain changes of scanned objects in order to automate the monitoring process to ensure their safety.

Objective. Formation of structurally perfect orthogonal Latin squares by the method of index ordering of the multiplication table elements of n-sets based on the multiplication table. Methods. Orthogonal Latin squares are formed by the method of index structuring of n-set multiplication tables. Results. A method is proposed for constructing structurally perfect orthogonal Latin squares of pairs of indexed finite sets of odd dimension, based on the index ordering of an nxn-array of elements in the multiplication table. A distinctive feature of the proposed method for constructing structurally perfect orthogonal squares from elements of two indexed sets of the same dimension is the use by the authors of the method of permutations of elements of the original nxn-matrix configurations, with the formation of index-ordered or index-structured combinatorial configurations. Conclusion. The use of the method for constructing a family of orthogonal Latin squares for pairs of indexed finite sets of the same odd dimension by the elements forming their multiplication table by the method of index structuring based on the principle of functional dependency of the index values on pairs of set elements and index values on pairs of elements from its environment allows creating a specific class orthogonal configuration, which, in terms of element indices, easily demonstrates their orthogonality.

Objective. Modeling the human head is a significant problem that arises in a wide variety of fields of science and technology. Existing active technologies for reconstruction and modeling of the object under study require expensive equipment and trained personnel. Methods. An alternative is to use passive methods that perform image processing using special mathematical algorithms. One of these methods is the stereo vision, which is based on the use of paired images taken simultaneously with several cameras positioned and calibrated in a certain way. However, a common drawback of stereo vision methods is the possibility of obtaining erroneous depth maps due to poorquality source images or incorrect camera and lighting settings. Results. Procedures were developed that use additional parameters of image points, which can be used to correct depth maps to avoid the appearance of defects. To achieve this objective, the existing mathematical software for processing photo and video materials is analyzed; methods for suppressing noise in the image, obtaining an image contour, as well as a method for obtaining a 3D object matrix based on changing the direction of illumination are proposed; the algorithm is tested on a test example. Conclusion. The developed technique should improve the quality of the depth map of the processed image and thus make the modeling procedures more efficient.

Objective. The objective of the study is to determine various stable characteristics of images (semi-invariants and invariants) as descriptors necessary for the formation of a feature space of standards intended for recognizing images of different nature belonging to different classes of objects. Methods. The authors propose metrics for evaluating the proximity of the recognized image to a given standard in the space of covariance matrices, based on the obtained descriptors as a methodological basis for constructing image recognition methods. Results. The content of the main stages of selecting descriptors for a given class of objects is developed, taking into account the different illumination of the recognized images. The effectiveness of the results obtained is confirmed by experimental studies related to the solution of the problem of recognition of special images - facies. Conclusions. The definition of stable image descriptors as invariants or semi-invariants to zoom and brightness transformations allows solving the problems of facies classification in conditions of the unstable shooting of recognized images. The images can be rotated and shifted in any way. In general, the proposed approach allows developing an effective image recognition system in the presence of various types of interference on the recognized images.

Objective. Determination of the stress state of a ground base with a trapezoidal cutoff from the action of own weight, according to the conditions of equivalence of effects, is reduced to determining the stress state from the external surface load distributed according to the hydrostatic law. Methods. The problem of determining the stresses in the structure foundations at any degree of areas development of a plastic strain of the soil has a strict mathematical formulation, and similarity criteria can be obtained using a simpler construct of similarity theory. The simulation is performed by using similarity criteria based on which the model is executed, the loading conditions are determined, and the transition from the values measured on the model to the corresponding values of the full-scale structure is carried out. Similarity criteria can be obtained either with the help of similarity theory or with the help of dimensional analysis. An even greater effect of increasing the self-weight of a model made of transparent optically sensitive material can be achieved using the immersion method in conjunction with the centrifugal modeling method. If necessary, the stresses in the model area are fixed using the "freeze" method. Result. Using the equations system of the mixed problem of the elasticity and plasticity theory, and the scale method, similarity criteria are established for modeling stresses in the foundations of buildings and structures. Limitations on the choice of similarity multipliers for loose soils, the possibility of using the method of centrifugal modeling, as well as features of modeling connected soils are noted. Conclusion. A necessary condition for the similarity of the stress states of loose homogeneous bases in nature and the model is the equality of the similarity multipliers of the geometric scale and the force factor.

Objective. In this paper, the authors study problems of a plane strain of elastic bodies containing internal rectilinear fractures. In each case, the margins of the considered areas are supported by thin flexible coatings. The first part of the paper is devoted to the problem of an infinite elastic wedge, the faces of which are free from the outside and reinforced with a thin flexible material, and the bisector contains a rectilinear fracture with regular forces applied to the margins, and to the study of the stress concentration at the fracture vertices. In the second part of the paper, the authors consider the problem of an equilibrium radial internal fracture in the cross-section of a round pipe. The inner surface of the pipe experiences hydrostatic pressure; the outer surface is reinforced with a thin flexible coating. The purpose of the study in each of the presented tasks is to determine the values of the influence factor. Methods. Both problems are united by a single approach, in which the presence of a coating is modeled mathematically, using special marginal conditions obtained based on an asymptotic analysis of the exact solution for a strip or ring flexible coating of small relative thickness. In the first issue, the singular integral equation is derived using the Mellin transform, which allows proceeding to the solution of a system of ordinary differential equations and obtaining a singular integral equation relative to the derivative of the discontinuity function of the first kind with a Cauchy kernel. In the second issue, discontinuous solutions are constructed using the Fourier series, resulting in a singular integral equation of a similar structure. Previously, similar ideas were successfully implemented by the authors in the study of the problem of the equilibrium state of a strip with a coating weakened by an internal transverse fracture under arbitrary conditions on the lower edge of the strip. Conclusion. Singular integral equations for the considered problems are obtained. The collocation method is used to construct solutions of singular integral equations for various combinations of geometric and physical characteristics of issues. In all the considered cases, the values of the influence factor were calculated. The analysis of changes in the influence factor depending on various combinations of geometric parameters and mechanical characteristics of problems is carried out. It is noted that with increasing rigidity of the coating and increasing its thickness, the values of the influence factor decrease; the increase in the value of the influence factor is provided by approaching the fracture to the body margin and increasing its relative length.

Objective. The development of structures and calculation of metal-wood crane beams are associated with specific difficulties. The article discusses the methods of calculation and design of metal-wood crane beams. In this case, an algorithm is described that allows designing systems that are rational in terms of material consumption. Methods. As an example, a metal-wood beam with a span of 12 m is used, which is supported by overhead cranes with a load capacity of 30 tf. The operation of a metal-wood crane beam was compared with a glue laminate crane beam without reinforcement. The reinforcement elements are "discarded" and replaced with elasto-yielding supports to calculate a glue laminate beam reinforced with metal elements (or a metal-wood beam). The flexibility of these supports is taken into account using the elastic support ratio r, which is determined depending on the stiffness of the supports, and the force in the metal elements is derived from the nodes balance. Result. In both variants of loading metal-wood crane beams, it was shown that the greatest bending moment occurred when the bridge wheel was located above the elastic support. Conclusion. It is rational to use a metal-wood crane beam when operating bridge cranes with a lifting capacity of up to 30 tf; metal-wood crane beams are recommended to be designed with spans up to 12 m; the comparison of glue laminate crane beams with metal-wood beams showed that metal-wood beams were 40-55% more efficient.