The work is devoted to the detection of instability in the frequency of generators, which provide synchronization of digital communication networks. An algorithm for detecting short-term instability of the frequency of superstable quasi-harmonic oscillations

Keywords: synchronization, instability, frequency, Alan variation, multiplicative-transformative criterion, harmonics

In the article results of approbation of the experimental devices designed for visualization of blood vessels developed by the authors are presented. Experimental device number one is an emitter of infrared light, the experimental device number two is a emitter of visible red light. Devices can be recommended for use in patients with no factors impeding vascular imaging and in patients with elevated body mass index.

Keywords: infrared radiation, optical pair, photodiode, LED, introscopy, visible red light, vascular detection, complicated intravenous access, peripheral vein

The possibility of detecting viruses in biomedical research using the optoacoustic method with carbon nanotubes is considered in the paper. In this paper, we consider the setup used to detect optoacoustic responses from a sample, which allows the recording of optical-acoustic signals generated by carbon nanotubes attached to the surface of viruses in the blood and which have high optical absorption. When the sample is irradiated, the absorbed energy from the laser radiation is converted into kinetic energy by means of energy exchange processes. This leads to local heating and, consequently, to the appearance of a wave of sound pressure. By recording ultrasonic waves, it is possible to form a spectrum of the optoacoustic signal for the test sample, which can be used to detect the absorbing components in it.

Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production

An analytical review of the impact of electromagnetic fields on human health is performed. A method for studying the electromagnetic situation during the territorial planning of urban settlements is proposed. The intensity of the electromagnetic field of industrial frequency in four main functional zones of Rostov-on-Don is investigated. Areas with a favorable electromagnetic situation and areas of increased environmental risk for residents have been identified.

Keywords: Electromagnetic field, industrial frequency, functional zones, territorial planning, environmental risk.

The paper presents results of a study of operational recursive methods for quasiharmonic signals frequency estimating over a short observation interval. Such methods should be used, for example, for adaptive control of directional pattern of hydroacoustic antennas in inhomogeneous medium. We proposed recursive expressions for realizations of four methods of frequency estimation within the limits of sliding observation interval. The expressions require a minimum number of mathematical operations, which does not depend on the observation interval length. We carried out comparative analysis of the speed, accuracy, and stability of the methods. The stability of the methods was analyzed based on results of model signals processing with constant amplitude, frequency, and initial phase in presence of additive white normal noise. The accuracy was investigated by the processing results of signals with slow varying amplitude and phase. The paper also presents the results of processing of long sequences of modulated signals with additive noise within a sliding window with predetermined duration. The obtained results make it possible to select from among the four methods the optimal one according to one or more criteria.

Keywords: communication channel, directional pattern, frequency estimation, recursive method, accuracy of method, stability of method, sliding interval

Electromyography of masticatory muscles is an objective criteria for the adaptation of patients to orthopedic constructions. The aim of the study was to evaluate the adaptation of masticatory muscles of patients with terminal defects of dentition made a prosthetic appliance for teeth with implant constructions with a large number of supports and removable denture. As a result, when patients with terminal defects of the dentition are made prosthetic appliance with the help of implant structures with a large number of supports in 3 months, the maximum aproaching of the bioelectrical potentials of the masticatory muscles to the norm is observed. When patients are made prosthetic appliance with removable orthopedic structures, hypertension of the masticatory muscles decreases, but does not reach physiological values. It is recommended to use the method of surface electromyography of the masticatory muscles to monitor the effectiveness of orthopedic treatment and the degree of adaptation of the patient to the manufactured structures.

Keywords: Electromyography of masticatory muscles, terminal defects of dentition, implant constructions with a large number of supports, removable denture

An experimental investigation of two low-noise amplifiers is carried out. The first amplifier contains one cascade on the HMC374 chip, the second LNA contains two cascades on the same chip. Amplitude and amplitude-frequency characteristics of both amplifiers are obtained, a comparison with the passport characteristics is made. The amplifiers correspond to the passport data for all parameters, except saturation power at the upper boundary frequency.

Keywords: Low-noise amplifier, amplitude-frequency response, amplitude characteristic, saturation power

The simulation algorithm for the system of microwave electronic devices with the method of nonautonomous blocks is given in this article . The voltage-current characteristic of the wave nonlinear element, which is the basic element in the theory of the electronic wave chain, is calculated.

Keywords: microwave electronic device, electric circuit, wave non-linear element, four-terminal network, the current-voltage characteristic, method of nonautonomous blocks

The analysis of the existing management systems for investment and construction projects showed that the organizational and technological models used for the development of the calendar plans are static and do not reflect changes in the course of real-time work that does not allow synchronizing the terms of production and supply of resources and leads to significant losses in use of manpower and construction machinery. The adaptability of organizational and technological models in the developed intellectual building management system is ensured through the use of special algorithms and models for disaggregating planned and aggregating actual information on work, calculating deviations of actual characteristics from planned values, developing and making decisions to bring the model to the organizational and technological normality in real time mode

Keywords: management of investment and construction projects, organizational and technological models, adaptive systems, intelligent management systems, operational management of the construction site, pace of work

The article presents a comprehensive analysis of emission indicators from stationary sources and emissions from motor vehicles in the Rostov region and the city of Rostov-on-Don, as well as a comparative analysis for the two regions of the Southern Federal District. The forecast of the ecological situation is made and the adequacy of the proposed mathematical model is checked.

Keywords: emissions of pollutants, toxicity, exhaust gases, stationary sources, auto transport, internal combustion engine

When developing large information-measuring and control systems, special attention must be paid to the interaction of various blocks of the system with each other. For example, the structure of a software-hardware measuring channel consists of four consecutively connected elements: primary converter; analog-to-digital converter; software dynamic converter; digital to analog converter. To find the parameters of the measurement channel error, mathematical models were constructed for each of the blocks. Simulation modeling of the measuring channel was carried out. As the input signal, the first-order aperiodic link model is taken. To generate the interference signal, a random number generator with a noise level of 0.5 is used. The error for the measuring channel is found. The suggested mathematical model allows to find the tuning coefficients of the software of the measuring channel, which ensure the minimum information loss in the software-hardware measuring channel. The resulting model can be used in automatic control systems for the current identification of regulator settings.

Keywords: model of measuring channel, model of primary converter, adjustment of coefficients, error of measuring channel

In this study, the process of adsorption of modified rice straw was described using a mathematical description using kinetic and isothermal models. The models of pseudo-first order, pseudo-second order, Elovich and Lynuiver-Burke were used as kinetic models, and the Langmuir model and the Freundlich model are isothermal models.

Keywords: adsorption, adsorption kinetics, adsorption isotherms, Langmuir, Freindlich

The article considers the question of finding similarity between objects containing unstructured information based on the spectra of two objects. To find the spectrum, we use the adjacency matrix of the graph. The similarity between objects of comparison is determined using the approach based on the singular expansion of the graph contiguity matrices. Also in the article the existing solutions are considered and examples are given of the areas of possible application of the described approach

Keywords: spectrum of the graph, singular decomposition, adjacency matrix, unstructured information, analysis of large arrays of information

The article considers the experimental estimation of the heat transfer coefficient in a hybrid immersion cooling system with contact point cooling and dry zones. The change in the heat transfer coefficient is made through a change in the Reynolds number for the flow of the coolant in the immersion cooling system. The experimental investigation is carried out on the basis of a numerical simulation model of the process under study. As a result, the dependences of the thermal resistance of the processor-heat exchanger system on the heat transfer coefficient and on the Reynolds number of the turbulent flow were obtained, and the results with the simulation results were estimated. It is found that, with an increase in the Reynolds number, the heat transfer intensification is weaker than the theoretical one. The refinement coefficients for the case under consideration are found.

Keywords: processor, heat flow, thermal resistance, Laplace equation, turbulent flow, Reynolds number, heat transfer, immersion cooling system, immersion cooling system, cavitation

In this study, the task is to simulate the cooling system of supercomputers with a heat pump on the reverse Stirling cycle by numerical simulation of heat transfer processes in the object under study. The results of numerical simulation of heat transfer processes in the superheater processor cooling system with a heat pump on the reverse cycle are presented. A numerical model of the heat transfer process was investigated. As a result, the dependencies of the required thermal lift of the heat pump are obtained taking into account the thermal resistance of the system. The first liquid cooling circuit - the cold cylinder of the heat pump and the hot cylinder system - the second liquid cooling circuit, depending on the heat transfer coefficient of the heat pump.

Keywords: processor, heat flow, thermal resistance, Laplace equation, heat pump, heat exchange, Stirling backflow, cooling system

The work of the sensors of passenger traffic control in conditions of a dense stream of people in the controlled section of the doorway was conducted. The results showed the possibility of determining the direction of movement of a person due to a change in the distance between the sensor and the moving person. The interference due to the high density of passenger traffic, which, however, does not lead, however, to the development of the corresponding algorithms, to false alarms of the sensors is detected. However, additional field studies are required on the vehicle of the passenger counting device based on ultrasonic distance measurement sensors

Keywords: passenger, ultrasound, passenger transport, road transport, distance sensor, Arduino, bus

Currently, great importance is given to the use of mathematical modeling in the conduct of system analysis. The article reveals the definitions of system analysis and mathematical modeling. Problems that can be solved with the help of system analysis are described, and the main tasks of system analysis are formulated. It is noted that system analysis is used mainly for research and design of large and complex systems. The methodological bases for the development of a mathematical model are analyzed.

Keywords: system analysis; model; system; math modeling; mathematical model

The relevance of the scientific work, the purpose of which is to set the task of planning routes for the delivery of valuable goods, is based on the existence of a significant demand for the delivery goods with the participation of specialized transport companies. It is proposed for the graph model of the transport network to create matrices that affect the complex assessment of traffic between all nodes of the route depending on the time of day and day of the week, and the experience of the personnel accompanying the goods. Integrated assessment evaluation includes cost, duration and safety of delivery. The result of the solution of the problem is the traffic route of delivery that meets the criterias.

Keywords: route planning problem, shortest path problem, transportation safety, graph model

The article describes the general model of the information system for managing information flows when renting real estate using the technology of distributed registries on the corda platform. The description of participants of the information system is presented. The key concepts of the use of distributed register technology for the implementation of the information system for real estate management are considered. The methods of data analysis of the information system for real estate management are presented. A method for approximating data using the Lagrange polynomial is considered. A method for estimating the value of real estate using artificial neural network technology is described.

Keywords: rent, real estate, data analysis, information security, neural network, distributed registries, Informatics, information system, corda

At the moment one of the most advanced flexible methodologies IT project management is SCRUM technology. Its feature is the partition of the whole work on short iterations (sprints), each of which represents a cyclic process, repeated all the way through the product development process. This allows you to constantly monitor the emerging risks and minimize them effects. Each sprint starts with planning, which sets the pace of work and stimulates high performance. The key point of planning is predicting the level of focus of the team on the implementation of the tasks, the so-called focus factor. It is the ratio productivity to labor intensity. The paper presents the results of numerical experiments to identify the best methods for predicting this indicator. In their the production data of one of the project groups of the real commercial firm in the field of IT. Extrapolation forecasting methods with a sliding base on the previous actual results. At the same time, the width of the base one to seven previous periods), and the type of extrapolating function. Approximating polynomials of zero, first and second degree are considered. Attention has also been paid to the method of exponential smoothing and Bayesian approach to diagnosis and prediction. For the integral the quality of forecasting used the value of the root-mean-square relative performance error. According to the results of the experiments, three optimal variants are selected. The first is the forecast for the sliding arithmetic average of the actual focus-factors for 3-4 previous periods. In the second variant, again, the sliding the average of actual focus factors for 3-5 sprints, but not arithmetic, and geometric. The third method for predicting is the product theoretical focus factor on the actual. We use the geometric mean it per the 1-2 sprints. In the mean square norm for both methods, the prediction error is the same, about 5.8%. If we estimate it not by the mean square metric, but by maximum deviation, then the latter option is slightly better. Results are intended to clarify the intuitive planning of sprints when performing real projects.

Keywords: management, IT-project, SCRUM technology, sprint planning, forecast, focus factor, moving average, linear and quadratic regression, exponential smoothing, Bayesian approach, root-mean-square error, the best possible option

Using a device of close homogeneous exponential queueing networks (QN) a mathematical model of an distributed information system functiouning for solving the problem of getting integral indexis on the basis of local computing network on the basis of three- level client server arhitecture. The base correlation for transitione matrix probabilities constraction and intensitiese of service at the network nodes are given.The peculiarity of the model being worked out is in making a selective choice of information at the database servers and via the channel of communication not the full data base is transmitted but some separate parts of it, which satisfy the conditions of SQL-request search.

Keywords: Distributed information system, distributed data base, local computing system, mass service network, conceptual model, exponential law of distributing the random value, stationary probability, mark process, the global balance equation, system reaction tim

The field studies of the device in a controlled section of the doorway of the trolleybus were carried out. Studies have shown the operability of the device with the appropriate information processing algorithm, which allows to extract an information signal from short-term interference. It is necessary to carry out on the vehicle additional field studies of the passenger counting device based on ultrasonic proximity sensors aimed at eliminating the reflection of interference from the walls and, accordingly, improving the accuracy of counting the number of incoming and outgoing passengers.

Keywords: passenger, ultrasound, passenger transport, road transport, distance sensor, Arduino, trolleybus

A base model of impact in a social network is a weighted directed graph. Its vertices correspond to the members of a social group, and its arcs describe their mutual impact. A real value (an opinion of the group's member) as a function of time is ascribed to each vertex, and a real number (weight) is ascribed to each arc (a degree of impact of one member of the group to another or, what is the same, a degree of confidence of one member of the group to another). All strong subgroups (non-degenerated strong components of the digraph) develop their final opinions which depend only to the initial opinions of their members. The final opinions of other members of the group are linear convolutions of the final opininions of all strong subgroups. The most interesting question for applications arises when one or several decision makers are not satisfied by the received final opinions. To formalize such situation the base model is extended by an introduction of a set of the impact agents which can exert influence to the basic agents. The impact agents may change the initial opinions of the basic agents or the factors of their interaction. This leads to the optimal control problems or dynamic games on networks. The respective setups and their marketing interpretation are presented in the paper.

Keywords: directed graphs, differential games, dynamic control models, marketing research, social networks