Purpose of research. The article considers the possibility of increasing the probability of correct authentication of a remote message source based on the analysis of metadata of the network packets it generates. The purpose of this purpose is to develop a method for classifying authentic network packets based on the analysis of statistical characteristics of the packet arrival time and to optimize the classifier parameters to achieve maximum accuracy in determining authentic packet sequences.
Methods. The study applies methods of analyzing high-order moments of interpacket intervals, as well as logistic regression for classifying packets. The parameters of excess and asymmetry calculated based on samples of time intervals formed by the arrival of packets are used. A classifier based on minimizing the distance from pairs of values (asymmetry and excess coefficients) to a parabola corresponding to the Poisson distribution is developed.
Results. Samples with a power of 10⁴ with calculated pairs of excess and asymmetry coefficients were formed. The obtained results show that for the maximum possible classification accuracy (82-84%), the optimal parabola parameters are: a ≈ 1.0, c = 8–9. ROC curves were analyzed for different sets of parameters, which confirmed the linearity of the dependence of the proportion of true positive results on the proportion of false positives.
Conclusion. The results of the study confirmed the possibility of increasing the reliability of network packet authentication by using high-order moments of time interval data, which demonstrates the effectiveness of the proposed method. The main conclusions include the need for careful tuning of the classifier parameters to optimize the authentication process. Since the proposed method exhibits high sensitivity to changes in distributions, this opens up new directions for further research in the field of wireless network security.

Purpose of research. One of the key tasks of modern society is the prolongation of human life. It is important to understand the signs of aging of the body, especially its cardiovascular system. This will allow us to determine the most effective criteria for assessing age-related changes in the cardiovascular system. Therefore, consideration of real data on the state of the cardiovascular system of centenarians using cardiometric analysis will make it possible to take a step towards a real understanding of the prolongation of active longevity.
Methods. The cardiometric method of analyzing the phases of the cardiac cycle was used, based on the mathematical model of hemodynamics by G. Dueltsev – O. Voronova, which made it possible to evaluate the dynamic characteristics of the cardiovascular system and establish criteria for maintaining normal hemodynamics. When using cardiometry in the study of centenarians, their residence in different geographical regions, as well as the different climatic conditions of these places, were taken into account.
Results. Hardware and software tools for radiometric analysis of the structure of the cardiac cycle have been developed. The study examined people over the age of 90 according to indicators including metabolic and hemodynamic parameters. The imbalance of hemodynamics of the large and small circulatory circles has been established. The main reason for the change in parameters is incomplete breathing, which affects the balance of oxygen and carbon dioxide in the blood. At the same time, there was a decrease in the level of creatine phosphate in the myocardial muscles, which characterizes the energy potential of muscle contraction. This is related to changes in the state of the cardiovascular system, which are most reflected in the phase structure of the cardiac cycle in the systolic phases R-S-L-J. The real data obtained using a commercially available hemodynamic analyzer is presented.
Conclusion. The paper provides a method and effective criteria for assessing age-related changes in the cardiovascular system.

The purpose of the research is to develop a method for restoring clock synchronization for signals demodulators with square amplitude manipulation.
Methods are based on the foundations of quasi -optimal receipt of multi -position signals, the theory of constructing radio -receiving systems of digital communication lines, methods of mathematical modeling of signals, probability theory and mathematical statistics. The well -known algorithms for assessing the phase of clusion of clusion in the presence of manipulation interference, due to a multi -level signal modulation, were used. The assumption was assumed that the channel satisfies the conditions of Naquvist, and the distorting hindrance signal is an additive white Gaussian noise.
Results. The development of a method for restoring clock synchronization is implemented, which consists in using solutions and reducing each pair of adjacent symbols to a binary signal by centering them relative to the zero point and weighting by level. Analytical dependences of the phase estimate for the clock synchronization device are presented, as well as structural and functional diagrams of the implementation of various options for constructing this device as part of demodulators of multi-position signals with quadrature-amplitude manipulation. The obtained graphs of the components of the fluctuation characteristic of the discriminator of the clock synchronization device indicate that the developed algorithm allows resolving the contradiction between the reduction of the manipulation component and the growth of the noise component of the fluctuation characteristic.
Conclusion. From the point of view of the noise immunity of the optimal, coherent demodulation of signals is, however, a clock (phase) synchronization of the reference generator of the demodulator with the received signal, namely ensuring the coincidence of clock impulses in the decisive device with the ends of the end of information symbols. The use of the developed method, as shown by the results of theoretical and experimental studies, allowed about 0.5 to 0.7 dB to increase the noise resistance of the demodulator of radio -receiver systems of digital communication lines.

The purpose of the research is to determine the permissible and limiting modes of vibration loading of a plate imitating an aircraft skin element and made of D16a alloy, followed by the assembly and commissioning of an experimental research stand for the appearance and development of the stress-strain state of this plate. The cyclic effect of broad-band random vibration simulates operational operating conditions that cause the loss of elastic properties of the material and its aging, accompanied by a decrease in the angle of inclination of the hodograph formed by a three-dimensional vector of vibration accelerations relative to the horizontal plane.
Methods. Mathematical modeling methods were used to determine the permissible and limiting modes of vibration loading of the plate. The study of the aging processes of the plate material, accompanied by loss of elastic properties, is performed by an equivalent cyclic method, each cycle of which contains two phases: the first is the phase of vibration loading of the plate, the second is the phase of visual and X-ray laboratory control, during which internal defects in the plate structures must be detected (if any) or their development recorded. The detection of such defects indicates a likely imminent violation of the integrity of the plate imitating the aircraft skin element.
Results. The values of the permissible and maximum load on the plate imitating the aircraft skin element are determined. The assembly and commissioning of a stand for experimental studies of stress-strain state processes has been carried out, and the hypothesis that the hodograph formed by a three-dimensional vector of vibration accelerations has an initial angle of inclination relative to the horizontal plane of 45° has been confirmed. However, there has not yet been a noticeable aging effect in which the specified angle changes.
Conclusion. Changing the angle of inclination of the hodograph formed by a three-dimensional vector of vibration accelerations makes it possible to judge the degree of wear of the materialwith the possibility of further forecasting the remaining life of the material. It is proposed to continue the research in terms of collecting an array of experimental data.

Purpose of research. The relevance of the conducted research is due to the fact that in recent years, unmanned underwater vehicles have become more accessible and effective, which has led to their widespread use and implementation in various industries, including solving the problems of the Ministry of the Russian Federation for Civil Defense, Emergencies and Elimination of Consequences of Natural Disasters. The technological advancement of these devices allows performing tasks underwater without direct human participation through the use of sensors, cameras and a number of other devices with high tactical and technical characteristics.
The purpose of the research is to assess the maximum transmission range of FullHD quality video information from an unmanned underwater vehicle for identifying underwater objects during monitoring by rescuers in emergency situations.
Methods. The research methods are based on the basic provisions of radio communication theory, diagnostic theory and methods for predicting the technical condition of underwater vehicles. The principles of transmitting video information from unmanned underwater vehicles used to monitor the seabed are analyzed. A critical assessment of the maximum distance of removal of an unmanned underwater vehicle from the operator in a rescue operation is made.
Results. The energy reserve indicator in a communication channel with a frequency of 1 GHz during data transmission at speeds corresponding to the plesiochronous digital hierarchy was estimated to be 50–70 meters. The signal attenuation was estimated, in which at a distance of 100 meters from the source electromagnetic waves weaken by 200 dB. The maximum range of radio transmission in underwater space at a frequency of 1 GHz using KAM-16 and turbo codes 3/4 was estimated to be 55 meters.
Conclusion. The use of high-speed short-range radio communication technology, which helps ensure the secrecy of underwater radio communication, should be considered as promising areas of research in the field of using unmanned underwater vehicles in water space.

The purpose of the research is to develop and compare various methods of processing medical images in order to optimize visualization of pancreatic structures. The main task is to identify the most effective image processing method to achieve the best visualization quality, which, in turn, is important for the accurate diagnosis and treatment of patients with pancreatic pathologies.
Methods. As part of our research, various methods were applied, including the analysis of a huge bibliographic material, the use of various tools for data collection, and the involvement of expert knowledge and approaches.
Results. The results obtained are discussed taking into account their practical significance for medicine. Optimization of visualization of the pancreas using various image processing methods can significantly improve the accuracy of diagnosis of its diseases. Improved visualization makes it possible to more accurately identify and analyze pathological changes, which contributes to the early detection of diseases and more effective treatment of patients. This can contribute to further improvement of methods of diagnosis and treatment of pancreatic diseases, improving the quality of medical care.
Conclusion. Different segmentation methods, such as threshold processing, machine learning, and active contours, have their advantages and limitations in visualizing pancreatic structures. The choice of the optimal method depends on the specific task and the requirements for the accuracy and speed of image processing. Further research should focus on developing more efficient segmentation algorithms and their applicability in clinical practice to improve diagnosis and treatment of pancreatic diseases.

The purpose of the research is to develop methods for controlling unmanned aerial vehicles based on the analysis of data coming from a video stream.
Methods. An unmanned aerial vehicle can lose contact with the satellite navigation system, so the task of ensuring its orientation using an onboard photo video recorder with onboard data processing becomes relevant. For this purpose, special points on the terrain are used, the identification of which in the picture allows restoring the orientation of the aircraft. To search for special points of the blob type in the picture, a method is proposed for transforming the original image into a criterion image, after threshold processing of which the coordinates of the blobs are obtained. A method has been developed for transforming the original image into a criterion image, which consists in determining correlation images. For each correlation image, a scalar blob identification criterion is determined, which allows determining the coordinates of a special point in pictures obtained from an onboard photo video recorder.
Results. To improve the accuracy of determining the coordinates of blobs in pictures, an aggregated blob of three special points was used. An algorithm for two-stage identification of coordinates of an aggregated blob is investigated. At the first stage, the coordinates of special points closest to the coordinates of the vertices of the aggregated blob are determined, and at the second stage, the coordinates of the vertices of the triangle whose center of gravity is closest to the center of gravity of the aggregated blob are determined. The algorithms for searching for special points have shown their efficiency at a high level of interference modeled in the image by means of Gaussian noise, as well as interference associated with the deviation of the aircraft from the specified course.
Conclusion. The formation of an aggregated blob with subsequent multi-stage identification allows for increasing the accuracy of determining its coordinates, and also makes it possible to record the deviation from the course of the aircraft in the area of two adjacent images and introduce appropriate corrections into the navigation system.

The purpose of the research is to evaluate the accuracy and reliability of methods for measuring the impedance of a biological material and to develop recommendations for improving algorithms for the development of software and hardware complexes in the field of biomedical diagnostics. Considerable attention is paid to the analysis of data obtained in Vivo.
Methods. 400 measurements were performed on a group of 20 volunteers using electrical thermal effects to obtain amplitude-phase frequency characteristics of the impedance of biological tissues. During the experiment, the Cole method was used to determine coefficients reflecting the key parameters of the test tissue and its impedance characteristics. To generate the test signals, sequences of single-frequency sinusoidal signals were used, controlled by software on the E20-10 platform, specially designed for digitizing data and analyzing transients in living tissues.
Results. Based on the E20-10 data acquisition system manufactured by L-Card CJSC, a complex for receiving and processing impedance data was developed, including software implemented in the Delphi language designed to generate and process test signals. The in Vivo results showed average discrepancies within 4% between the measured and expected values, which confirms the high accuracy and reliability of the proposed approach to measuring the resonance of biological tissues.
Conclusion. The implementation of software for measuring biomaterial impedance using the developed algorithms and applied amplitude-phase frequency characteristics provides a more accurate assessment of the dissipative properties of biological tissues. Data analysis has shown the possibilities and prospects of developing high-precision classifiers for a decision support system for early diagnosis of medical risks. These classifiers can be especially useful for identifying predisposition to lung diseases such as pneumonia and tuberculosis. Further research in this field can lead to significant progress in the creation of effective software and hardware complexes for biomedical diagnostics, contributing to the improvement of the prevention and treatment of various pathologies, taking into account the individual characteristics of the patien

The purpose of the research is investigation of the parameters of nonlinear interaction of low-frequency acoustic radiation with biological tissues to improve the accuracy of determining structural changes in organs and tissues by elastography.
Methods. Improving the accuracy of determining the degree and nature of structural changes in human organs and tissues is an urgent task today. The use of nonlinear effects of the interaction of powerful low-frequency acoustic radiation with biological tissues will allow obtaining new information characteristics, as well as improving the accuracy of differentiation of various degrees of structural changes in tissues and organs at the initial stages of diseases. In the framework of this work, the relationship between the viscoelastic and nonlinear characteristics of biological media and the processes of propagation of elastic transverse waves in them is considered. The physical foundations of the processes of formation and propagation of harmonic components of a transverse acoustic wave, as well as the change in its ratio N to the fundamental frequency wave, are also considered.
Results. The results of mathematical modeling of the processes of changing the correlation between the amplitude of the fundamental frequency wave and the third harmonic formed in the medium due to the nonlinearity of the interaction of acoustic radiation with biological tissues are obtained. The results were the graphs of the dependence of the change in N with distance for liver tissues at various stages of fibrosis and fatty hepatosis.
Conclusion. The obtained dependences allow us to conclude that the use of nonlinear effects of the interaction of low-frequency acoustic radiation with biological tissues will improve the quality of diagnostics of structural changes in organs and tissues in the early stages of diseases, when standard linear methods are less informative.

Purpose of research. The article considers a model for processing messages received by the receiver from several sources. For a class of distributed systems with restrictions on the size of transmitted messages and the size of their identification fields, it is relevant to use block coupling encoding, which, with the identifier size unchanged, implies a significantly lower probability of identifier collisions. A negative consequence of this is the need to identify the source not for a single message, but for a sequence of messages associated with the source. As a result, the receiver can consider the same message at any given time as a potential message from several sources, forcing it to be stored in various banks of intermediate calculation results. The aim of the work is to reduce the probability of error in determining the source of messages by taking into account the results of parallel processing in independent structures.
Methods. An approach to improving the reliability of message processing is considered. It consists in the parallel formation of dynamic structures storing messages that can be associated with the corresponding source. When deciding whether a message belongs to one of the sources under consideration, information about such a message is deleted from all structures in which it was contained, since for such structures this message is extraneous.
Results. A mathematical model of parallel message processing in independent structures has been created. The probabilities of errors are calculated based on the use of the method without using joint message processing and using. The dependences of error occurrence on the intensity and length of messages are graphically plotted. Error probability values were obtained for the two compared data processing options.
Conclusion. The article shows how using the results of message processing in independent structures associated with the corresponding source of a distributed system can affect the reliability and complexity of the process of determining the sources of messages encoded in the block coupling mode.

The purpose of the research is to synthesize fuzzy diagnostic models for transient neurotic disorders based on hybrid fuzzy models that improve the quality of decisions.
Methods. Exploratory analysis has shown that the data structure describing the desired class of mental disorders is fuzzy, which makes it advisable to use fuzzy decision-making logic, and specifically the methodology for synthesizing hybrid fuzzy decision rules. The composition of informative indicators describing transient neurotic disorders in the composition of signs accepted in traditional medical practice, the level of adaptation of the body as a whole, the electrical imbalance of biologically active points associated with neuroses, confidence in the prognosis of the appearance of neuroses, quantitative characteristics of the functional reserve of target organs and systems is determined. For these groups of indicators, private diagnostic models have been obtained, the aggregation of which gives the final diagnostic model.
Results. To assess the quality of admissions, three levels of quality control were used: at the expert level; according to model control samples and according to control samples in which the presence of transient neurotic disorders was checked using independent generally accepted research methods. The quality of the classification was checked by such indicators as diagnostic sensitivity, specificity and diagnostic effectiveness, which exceeded the value of 0,97.
Conclusion. The paper provides fuzzy models for the diagnosis of transient neurotic disorders. An assessment of the quality of decisions made using expert assessment methods, mathematical modeling and statistical analysis showed that the hybrid fuzzy models obtained provide acceptable diagnostic quality with a confidence of at least 0,97.

Purpose of research. Pandemic of 2019 has greatly altered human life and affected economies worldwide by increasing death rates. The relevance is understanding and controlling the spread of infections is vital to minimizing its effects. The purpose of the research investigation is to plug spatial dependence into the traditional SIR model to extend its usefulness in modeling the propagation process of the virus.
Methods. The methodology is to develop of a mathematical model to represent the pandemic spread as a traveling wave phenomenon. Analysis of the wave speed of the model is made as appropriate as well as the several numerical methods it applied in obtaining solutions. The new variable to the infected population equation is used along with variable transformation techniques and linearization in deriving analytical solutions and then computing and analyzing the wave speed associated with infection spread.
Results confirmed the previous outcomes generated by time-dependent models’ analysis that the prime determinant of disease dissemination is the infection-to-recovery rate. It is shown that either transmission coefficient decreases or the recovery rate increases slows down the spread of the disease.
Conclusion. As a conclusion, the best possible way to curb its exposure is by minimizing interpersonal interaction (reduction of beta) or by expediting patient recovery and segregation (increase in alpha). It reduces the wave speed parameter q, which controls the rate of propagation of the disease.