Systems For Various Purposes Research Articles

Physical effects of geocosmic storms. Part 3

A review of the results of observing the effects of the most interesting ionospheric and magnetic storms that took place in 2018–2019 is presented. Ionospheric and magnetic storms are considered as components of geocosmic storms. In accordance with the systemic paradigm of L.F. Chernogor, a geocosmic storm is a complex of processes caused by a solar storm, reduced to synergistically interacting storms in a magnetic field (magnetic storm), ionosphere (ionospheric storm), atmosphere (atmospheric storm) and electric field atmospheric-ionospheric-magnetospheric origin (electric storm). Using the analysis of specific magnetic and ionospheric storms as an example, it is shown that, in addition to general patterns, each storm has its own individual characteristics. The expediency of a comprehensive study of the manifestations of each new geocosmic storm has been confirmed. A wide variety of ionospheric and magnetic storms have been confirmed. A weak magnetic storm is not necessarily accompanied by a weak ionospheric storm, while a strong one is accompanied by a strong one. An ionospheric storm can be single-phase (positive or negative) or multi-phase, when the phases alternate. Storms can last from several hours to many days. Storms are accompanied by both aperiodic and quasi-periodic variations. The latter are caused by atmospheric gravity waves (periods 10–180 min) and infrasound (period less than 5 min). Of all the components of a geocosmic storm, except for academic ones, ionospheric storms are of the greatest practical interest. It is these storms that limit the potential characteristics of radio systems for various purposes (telecommunications, radio navigation, radar, remote radio sounding, radio astronomy). It is shown that ionospheric storms are accompanied by the appearance of multipath, broadening of the Doppler spectra (and even their collapse), significant aperiodic and quasi-periodic variations in the Doppler frequency shift, the amplitude of radio signals, and the trajectories of radio waves in the decameter range. In particular, the height of reflection of radio waves changed during ionospheric storms by 50–180 km. The electron concentration during moderate negative ionospheric storms decreased up to 2 times, and during moderate positive ionospheric storms it increased up to 3 times. Under the action of atmospheric gravity waves, the relative amplitude of quasi-periodic variations in the electron concentration reached 50%, and due to low-frequency infrasound, it did not exceed 0.7%.

Establishment of intestinal organoids from small intestine of growing cattle (12 months old)

Recently, we reported the robust in vitro three-dimensional (3D) expansion of intestinal organoids derived from adult bovine (> 24 months) samples. The present study aimed to establish an in vitro 3D system for the cultivation of intestinal organoids derived from growing cattle (12 months old) for practical use as a potential alternative to in vivo systems for various purposes. However, very few studies on the functional characterization and 3D expansion of adult stem cells from livestock species compared to those from other species are available. In this study, intestinal crypts, including intestinal stem cells, from the small intestines (ileum and jejunum) of growing cattle were isolated and long-term 3D cultures were successfully established using a scaffold-based method. Furthermore, we generated an apical-out intestinal organoid derived from growing cattle. Interestingly, intestinal organoids derived from the ileum, but not the jejunum, could be expanded without losing the ability to recapitulate crypts, and these organoids specifically expressed several specific markers of intestinal stem cells and the intestinal epithelium. Furthermore, these organoids exhibited key functionality with regard to high permeability for compounds up to 4 kDa in size (e.g., fluorescein isothiocyanate [FITC]-dextran), indicating that apical-out intestinal organoids are better than other models. Collectively, these results indicate the establishment of growing cattle-derived intestinal organoids and subsequent generation of apical-out intestinal organoids. These organoids may be valuable tools and potential alternatives to in vivo systems for examining host-pathogen interactions involving epithelial cells, such as enteric virus infection and nutrient absorption, and may be used for various purposes.

MANAGEMENT OF THE SYSTEM «CDP DISPATCHER POWER SUPPLY SYSTEMS - PRODUCTION ENVIRONMENT» AS A TOOL FOR OPTIMIZATION OF WORKING CONDITIONS

Ensuring industrial safety, labor protection, health of workers, including in the field of electricity, is an urgent task today. This task is set out in the development strategies of the European Union, the United States, Canada and others. This position of the states is aimed at reducing the level of occupational injuries and occupational diseases, which is high, especially in the field of electricity in almost all countries. Analysis of the state of the solution of this problem shows that the working conditions of the staff of the power supply system, especially in the central control points, in many cases need to be improved. The study of the relationships in the system «dispatcher of the main control point of power supply systems - production environment» confirms the importance of solving the problem of improving their working conditions. The peculiarities of power supply system managers are revealed, which are due to the following two main facts. 1 - production activity of dispatchers of the central dispatching points is characterized by the considerable list of tasks which differ in character of the performed work. This necessitates frequent switching of their activities. This mode of operation causes significant psychophysiological loads in their body. 2 - the state of health directly affects the health and well-being of dispatchers during the work shift. This is especially true in emergencies, which require the maximum concentration of professional knowledge, the attention of dispatchers in developing the necessary solution to restore power. Thus, the task of ensuring proper (regulatory) working conditions, regulated by regulations, is complemented by the need to develop measures to optimize the regime «work – rest» during the work shift, ergonomics of the workplace. In this case, for example, while ensuring proper microclimatic conditions, it is necessary to ensure their optimal parameters, and the design or improvement of artificial lighting systems should be based on the qualitative characteristics of light flux. That is, the organization of the production environment should be improved not only taking into account changes in regulations, but also taking into account the latest advances in ergonomics, other areas in the field of providing a comfortable working environment. Based on this, the solution of the problem requires a comprehensive system approach. This approach is proposed to be implemented using the developed adaptive management system of working conditions, ergonomics, ie in general, the production environment in the central control point of the power supply system. A software algorithm for such a management system is presented. The presented methodology for developing an adaptive management system is universal. It can be implemented in power supply systems for various purposes. Keywords: power supply systems, central control point, labor protection, management, reliability of power supply.

Evaluation of the energy efficiency of rotary percussive drilling using dimensionless energy index

This paper sets forth a geomechanics framework for assessing the energy efficiency of rotary percussive drilling using the energy criterion, which has been proposed by Victor Oparin for volumetric destruction of high-stress rocks having nonuniform physico-mechanical properties. We review the long-term research and development in the specified area of science and technology, including research and development projects implemented at the Institute of Mining, Siberian Branch of the Russian Academy of Sciences. A new modified expression of Oparin's dimensionless energy criterion of volumetric rock destruction k is introduced. The range of in situ values is determined for the energy criterion of volumetric rock destruction at the optimized energy efficiency of rotary percussive drilling. The temporo-spatial intervals of geotechnical monitoring are found to control pneumatic drilling energy efficiency at subsoil use objects in Russia. The integrated experimental, theoretical and geotechnical approach to the comprehensive investigation of real-time processes of rock fracture in rotary percussive drilling using the energy concept possesses the necessary geomechanical performance-and-technology potential to create the next level geotechnical monitoring of drilling systems for various purposes, including determination of physico-mechanical properties and the stress-strain analysis of rock mass in full-scale drilling.

ГЕРМЕТИЧНІСТЬ ТА ПОЛІКРИСТАЛІЧНІ КОНСТРУКЦІЙНІ МАТЕРІАЛИ

Ensuring the tightness of rocketry structures, assemblies, individual structures and systems for various purposes is one of the important aspects of the development, production and operation of technical systems of the present and the future. In accordance with the requirements of the time for the operation and operation of the facility that is being developed, the technologies and means of ensuring tightness are changing. Modern requirements for the tightness of objects of the rocket and space industry, especially for those that are operated in conditions of weightlessness, vacuum, radiation exposure for a long time are extremely stringent.
 As shown by the experience of operating tanks designed for storing active rocket components of fuel and, accordingly, to the same extent aggressive, the frequency of loss of functionality due to depressurization statistically has two maximums: at the beginning of operation and a year or two after the start. If the causes and physics of the first are investigated in sufficient detail, then information about the nature of the second in open sources is completely absent.

Investigating Underrepresented Perceptions of Inclusively Designed Voiced Automation

Consumers are increasingly interacting with automated systems for various purposes (e.g., smart speaker, vehicle control). One of the most popular ways they communicate with these systems is via the spoken auditory channel (listening and speaking). However, most of these systems tend to default to a female voice. In addition, many specifically use a White-sounding female voice. While prior work has investigated how attributes of age and gender influence perceptions of voiced automation, an additional vocal attribute of humanness has not been well researched -race. The specific goal of this project is to examine how more inclusively designed AI voices (e.g. exhibiting attributes of race) affect Black users’ attitudes toward autonomous technology. Results are expected to show more preferential attitudes when automation exhibits similar vocal attributes to the user. Findings will add to our understanding of how a deliberately more inclusive design affects an underrepresented population’s attitudes toward technology.

UHMWPE textiles and composites

Ultra-high molecular weight polyethylene (UHMWPE) has the potential to make a significant contribution to the efforts currently being made to help to protect the environment by reducing carbon emissions through the substitution of heavy conventional materials with lightweight polymeric materials. Used on its own, UHMWPE also offers complete recyclability with thermoplastic matrices. UHMWPE fibre-based composites (both thermoplastic and thermoset) offer a wide range of applications in various fields such as military protective suits, automotive, aerospace, electronics hardware, tribological application, and biomaterial implants, and this issue of Textile Progress explores the behaviour of UHMWPE with different matrix systems for various purposes. UHMWPE is widely used in the development of ballistic protective armours. Apart from applications where impact resistance is a key requirement, UHMWPE-based composites are currently being employed in the fields such as biomedical implants, anti-friction systems, dielectric and acoustic applications, and other structural fields; the UHMWPE should be extractable from the thermoplastic types and be able to be recycled. The various manufacturing techniques employed in the preparation of UHMWPE and its composites are discussed as are improvements aimed at eradicating existing processing issues associated with UHMWPE.

Problems and possibilities of applying the theory of antagonistic games in the analysis of economic systems for various purposes

In organizational and economic tasks related to decision-making at various levels of the hierarchy in various economic systems, conflict situations often arise. A distinctive feature of any conflict is that the interests of its parties are mutually opposed, that is, the economic result (winning) of one participant in the conflict is equal to the loss of the other participant. With the help of conflict situations, one can describe the opposition of competitors to each other in the oligopoly market, the struggle for resources between various interested parties, the relationship of tax authorities with unscrupulous taxpayers, and some other situations. The article discusses the practical application of the theory of antagonistic games to the problems of choosing effective solutions in the economy, analyzes the methodological features of this theory, formulates the main problems that arise when using antagonistic games in organizational and economic problems, analyzes some practical examples in which the use of this theory can be appropriate. Special attention is paid to the solution of computational problems, the economic interpretation of such game theory terms as strategy, win, efficiency criterion. As the main result of the work, it should be noted that: 1. Despite the fact that the theory of antagonistic games is currently developed mainly as a purely mathematical model, it may well find application in solving practical economic problems, in particular, for the oligopoly market. 2. Using the methods of the theory of antagonistic games to select optimal solutions in conflict situations encounters a number of difficulties, among which the most important are:
 determination of the set of strategies of the participants in the conflict;
 the correct choice of the criterion on the basis of which the conflict situation is analyzed;
 establishing the relationship between the optimality criterion and the strategies of the participants;
 formation of an efficiency matrix based on the values of this criterion for each combination of strategies of the participants in the conflict;
 search for equilibrium situations;
 study of the possibility of a multi-criteria choice in the context of a conflict of interest.
 
 The most widely used when choosing effective solutions in a conflict of interest is the principle of a guaranteed result, which is the easiest way to determine the equilibrium strategies of the participants.

Procedures for Self-Learning of Autonomous Intelligent Mobile Systems in Unstable a Priori Undescribed Problematic Environments

The article deals with topical problems of artificial intelligence related to the development of cognitive tools for visualeffective thinking of autonomous intelligent mobile systems, which provide them with the possibility of organizing expedient behavior in a priori undescribed problematic environments. A self-learning algorithm with an active-passive logic of behavior has been developed that allows intelligent systems to automatically generate conditional programs of expedient behavior that reflect the patterns of transformation of various situations of an a priori undescribed, unstable problem environment. A characteristic feature of the proposed self-learning algorithm is the imitation of testing trial actions in the current operating conditions, which gives the intelligent system the ability to study the patterns of the problem environment without changing the current operating conditions during the self-learning process, which may not be related to the specified goal of expedient behavior. For a formal description of the current situations of the problem environment, as well as conditional signals fixed in the generated conditional programs of expedient behavior, it is proposed to use fuzzy semantic networks. This allows autonomous intelligent mobile systems to accumulate experience of expedient behavior regardless of a specific subject area and transfer it to new conditions of an a priori undescribed problem environment, similar to the previously studied operating conditions. Boundary estimates of the complexity of self-learning algorithms are found that have a polynomial dependence on the number of vertices of fuzzy semantic networks compared with each other in the process of self-learning and the power of the set of trial actions worked out by the intelligent system, represented in its memory in the form of frame-like fuzzy specified structures. A simulation of the expedient behavior of autonomous intelligent systems was carried out, organized on the basis of the proposed self-learning algorithm, which showed its efficiency and effectiveness in adapting intelligent systems to a priori undescribed, unstable problem environments. The practical significance of the results obtained lies in the effectiveness of their use for the development of problem solvers for autonomous intelligent mobile systems for various purposes, which provide the ability to perform complex tasks in a priori undescribed real problem environments.

К вопросу о готовности преподавательских кадров к цифровому обучению

The question of teaching staff readiness to digitalize the educational process is considered in this paper. Digital education is a prerequisite for training of specialists meeting the requirements for the XXI century digital economy. There are a number of challenges in introducing digital learning, including those in engineering education. Digitalization of the technical subject area is very costly process that has its own specifics and requires developers to possess not only professional competencies related to a particular discipline, but also to be advanced in the arear of information and communication technologies. Besides modern teaching and laboratory facilities, and computer systems for various purposes, an important condition for promoting of digitization in subject teaching is teaching staff willingness to improve their teaching skills along with fluency in modern digital technologies.
 As an example of subject teaching, in this paper are considered informatization and digitalization of basic geometric and graphic training for students at technical higher education institutes. The analysis is carried out from the point of view related to preparation of the academic teaching staff for creation and implementation of the educational environment that meets the requirements for dynamically developing design as a type of engineering activity. The scheme for realization of mixed learning has been presented, which introduction is determined by students' individual work implementation, and the process of students' online geometric-graphic training during self-isolation for COVID-19 prevention has been described. An analysis of teacher's activity content increase in the full online training mode has been carried out. Has been presented a set of practical measures acting to raise the chair’s teaching staff qualification and providing readiness to solving urgent problems of students’ learning through the digital educational environment.
 As a conclusion of the study, it is stated that in digitalization conditions the most successful form for implementing of basic geometric and graphic training is the form of blended learning.

Safety Rules of Heuristic Behavior Algorithms as a Prototype of the "Morality" of Robotic Systems

The relevance of choosing the subject of research, as the use of autonomous robotic systems for various purposes and the object of research, which are algorithmic problems arising in terms of algorithm security control, is determined by the existing contradiction between the need for autonomous robotic systems and the complexity of the software implementation of this requirement. The study was conducted on the example of the application of robotics in the field of autonomous transport systems. The implementation of trends of autonomization in this area generates certain legal and technological problems related to the security of algorithmic support of autonomous systems. The manifestation of such problems are critical application errors that are problematic to identify at the development stage. In robotics, the main potential cause of these errors is the functioning of the software of autonomous robotic systems outside the framework of deterministic algorithms that were tested during their development. And if for conventional technical systems the consequences of application errors are predictable, and responsibility for their results is determined, then for the case of autonomous robots, the situation requires a solution. In the article, using general scientific methods of analysis and synthesis, the main aspects of the current state and prospects of the problem of algorithmization of the use of autonomous systems are investigated. Based on a review analysis of algorithmic problems of using autonomous robots, possible consequences and causes of algorithmic errors arising from their use, the formulation of the scientific problem of solving the problem of developing heuristic algorithms that determine their application using a dynamically formed system of predicate behavior similar to human morality is synthesized.

Physical effects of geocosmic storms

A review of the results of observing the effects of the most interesting ionospheric and magnetic storms that took place in 2018–2019 is presented. Ionospheric and magnetic storms are considered as components of geocosmic storms. In accordance with the systemic paradigm of L.F. Chernogor, a geocosmic storm is a complex of processes caused by a solar storm, reduced to synergistically interacting storms in a magnetic field (magnetic storm), ionosphere (ionospheric storm), atmosphere (atmospheric storm) and electric field atmospheric-ionospheric-magnetospheric origin (electric storm). Using the analysis of specific magnetic and ionospheric storms as an example, it is shown that, in addition to general patterns, each storm has its own individual characteristics. The expediency of a comprehensive study of the manifestations of each new geocosmic storm has been confirmed. A wide variety of ionospheric and magnetic storms have been confirmed. A weak magnetic storm is not necessarily accompanied by a weak ionospheric storm, while a strong one is accompanied by a strong one. An ionospheric storm can be single-phase (positive or negative) or multi-phase, when the phases alternate. Storms can last from several hours to many days. Storms are accompanied by both aperiodic and quasi-periodic variations. The latter are caused by atmospheric gravity waves (periods ~10–180 min) and infrasound (period less than 5 min). Of all the components of a geocosmic storm, except for academic ones, ionospheric storms are of the greatest practical interest. It is these storms that limit the potential characteristics of radio systems for various purposes (telecommunications, radio navigation, radar, remote radio sounding, radio astronomy). It is shown that ionospheric storms are accompanied by the appearance of multipath, broadening of the Doppler spectra (and even their collapse), significant aperiodic and quasi-periodic variations in the Doppler frequency shift, the amplitude of radio signals, and the trajectories of radio waves in the decameter range. In particular, the height of reflection of radio waves changed during ionospheric storms by 50–180 km. The electron concentration during moderate negative ionospheric storms decreased up to 2 times, and during moderate positive ionospheric storms it increased up to 3 times. Under the action of atmospheric gravity waves, the relative amplitude of quasi-periodic variations in the electron concentration reached 50%, and due to low-frequency infrasound, it did not exceed 0.7%.

Design principles of control systems for self-driving unmanned ground vehicles

The self-driving unmanned ground vehicles (UGV) design problem is analyzed in this paper. Two methodological problems of UGV design are formulated. The first problem is the difference between the purpose of creating a self-driving automobile from UGV, which leads to fundamentally different systemic solutions. The second methodological problem is associated with the need for sufficiently deep knowledge and the ability to work with a number of technologies that are used in the complex to create a control system for self-driving. The joint analysis of these problems allowed us to put forward a number of control systems design principles for self-driving UGV, including the principle of upcycling, the principle of using a discrete-event model for the logical synchronization of the operation of modules and the principle of ensuring the functional safety of the UGV during autonomous movement. The principle of using the discrete-event model for synchronizing the operation of software modules is explained by the example of a Petri net. A general solution to the problem of quantitative evaluation of the safety of autonomous movement of UGV is presented. The considered principles were used during development of prototypes of self-driving control systems for various purposes.

Effects of local intelligent energy systems integration

The energy sector of Russia is transforming, followed by total electrification and gasification, which has radically changed the fuel landscape and allowed enterprises in various sectors of the economy to create their energy sources based on gas turbine and gas piston cogeneration plants. There are more and more balanced local intelligent energy systems for various purposes, more often operating autonomously, since the process of their integration with the unified energy system of Russia is impossible without power and energy output, which is contrary to the interests of generating companies, territorial grid organizations and the system operator. Overcoming the administrative and technological barriers and obstacles created by significant players in the electric power industry reduces the technical and economic efficiency of local intelligent energy systems that can bring considerable beneficial systemic effects.THE PURPOSE Substantiation of the obtained system effects from integrating local intelligent energy systems.METHODS. A systematic approach to identify the effects of the integration of local intelligent energy systems with the unified energy system of Russia.RESULTS. Local intelligent energy systems are considered objects of distributed electric power industry that perform certain system functions, which is accompanied by a change in the properties of reliability, efficiency and environmental friendliness of the production and transmission of heat and electricity, which leads to various effects. The presence and size of the effects are determined by the type and type of the local intelligent energy system. It is shown that the integration of communal local intelligent energy systems, created for the energy supply of the population and equivalent consumers, has a certain advantage.CONCLUSION. The integration of communal local intelligent energy systems makes it possible to increase the availability and uninterrupted power supply, reduce the negative impact of off-market surcharges and cross-subsidization, improve the uniformity of load schedules for generating and grid equipment, which increases the efficiency of the unified energy system of Russia.

Analysis of NPP Pressure Compensation Systems Оperation

The article deals with the relevance of solving issues to improve the energy efficiency of the use of extracted hydrocarbon fuel, as well as the feasibility of developing and applying these measures in the economies of industrially developed countries. The necessity of having a permanent reliable source of electricity when using renewable and alternative sources of electricity is substantiated. As a permanent and reliable source of electricity, it is proposed to use operating and developing nuclear power plants. The use of these power plants requires the improvement of various systems for various purposes in them. To do this, the paper presents an analysis of the parameters of the steam and gas systems of pressure compensators to ensure the necessary pressure of the coolant in the first circuit of the nuclear power plant. Analysis of the parameters of operation of these systems is presented in tabular readable form. Based on the analysis, a "hybrid" pressure compensator system is proposed for detailed consideration, which includes the positive properties of the pressure compensator systems under consideration - steam and gas. An estimated calculation of the possible use of air (or gas) in the free volume of the pressure compensator with the provision of preliminary pressure is presented, followed by bringing the value of this pressure to the required value during operation. The advantages and disadvantages of the considered systems and some issues that require detailed study are noted.

Conversion of Classical Queuing Systems to Systems with Time Lag

The results of the classical queuing theory are used to model data transmission systems for various purposes, and the average delay of requests in the queue is used as the main characteristic for this. It is known that the average delay is directly proportional to the variances of random arrival and service intervals, which means its quadratic dependence on the coefficients of variation. Classical QS are applicable only in the case of fixed values of these coefficients of variation, which is a serious limitation. Unlike the classical theory, the article presents the results of research on QS described by the transformed distribution laws with a shift to the right. Such a transformation of the distribution laws with the introduction of a time shift parameter turns Markov QSs into non-Markov systems with delay. Spectral expansions and calculated formulas obtained on their basis for the average delay of requests in queue for sixteen QS with time lag are presented. These systems are obtained using four distribution laws used in queuing theory: exponential, hyperexponential, Erlang and hyper-Erlang. It has been theoretically and practically proven that in systems with time lag, the average delay is less than in classical systems. The resulting calculation formulas for the average delay expand and supplement the capabilities of classical systems. The spectral solutions allows you to calculate the average delay and its higher-order moments for these systems in mathematical packages for a wide range of flow parameters.

TWO PAIRS OF DUAL QUEUEING SYSTEMS WITH CONVENTIONAL AND SHIFTED DISTRIBUTION LAWS

Context. The relevance of studies of G/G/1 systems is associated with the fact that they are in demand for modeling data transmission systems for various purposes, as well as with the fact that for them there is no final solution in the general case. We consider the problem of deriving a solution for the average delay of requests in a queue in a closed form for ordinary systems with Erlang and exponential input distributions and for the same systems with distributions shifted to the right. Objective. Obtaining a solution for the main characteristic of the system – the average delay of requests in a queue for two pairs of queuing systems with ordinary and shifted Erlang and exponential input distributions, as well as comparing the results for systems with normalized Erlang distributions. Methods. To solve the problem posed, the method of spectral solution of the Lindley integral equation was used, which allows one to obtain a solution for the average delay for the systems under consideration in a closed form. For the practical application of the results obtained, the method of moments of the theory of probability was used. Results. Spectral solutions of the Lindley integral equation for two pairs of systems are obtained, with the help of which calculation formulas are derived for the average delay of requests in the queue in a closed form. Comparison of the results obtained with the data for systems with normalized Erlang distributions confirms their identity. Conclusions. The introduction of the time shift parameter into the distribution laws of the input flow and service time for the systems under consideration transforms them into systems with a delay with a shorter waiting time. This is because the time shift operation reduces the value of the variation coefficients of the intervals between the arrivals of claims and their service time, and as is known from the queuing theory, the average delay of requests is related to these variation coefficients by a quadratic dependence. If a system with Erlang and exponential input distributions works only for one fixed pair of values of the coefficients of variation of the intervals between arrivals and their service time, then the same system with shifted distributions allows operating with interval values of the coefficients of variations, which expands the scope of these systems. The situation is similar with shifted exponential distributions. In addition, the shifted exponential distribution contains two parameters and allows one to approximate arbitrary distribution laws using the first two moments. This approach makes it possible to calculate the average latency and higher-order moments for the specified systems in mathematical packets for a wide range of changes in traffic parameters. The method of spectral solution of the Lindley integral equation for the systems under consideration has made it possible to obtain a solution in closed form, and these obtained solutions are published for the first time.

Fiber optical WDM multiplexers/demultiplexers with low bending losses

Objectives. One of the topical tasks in the development of radio electronic systems for various purposes is a sharp increase in the volume and data transfer rate between the elements of the system. This problem is most successfully solved using fiber optic technology, which has no alternative to meet a number of indicators. The use of optical fibers (OF) as a physical medium made it possible to transfer large information flows over considerable distances. Increasing the capacity of communication systems is pushing manufacturers to develop new OF brands with improved optical and operational characteristics, which makes it possible to improve various optical components that use an OF as an active information transmission medium. The dual-channel single-mode wavelength division multiplexing (WDM) multiplexers/demultiplexers, which are one of spectral selective splitters types, are most widely used in fiber-optic communication systems. Among the advantages of WDM, it is worth to note the transmission of a large amount of information over one OF by the arrangement of channels at different wavelengths and the ability to transmit signals of several wavelengths simultaneously in both directions via one OF that do not interact with each other (duplex communication). During operation, WDM multiplexers can be subjected to various external influences that affect the operation and stability of the device parameters. Currently, there are no data on the effect of OF bending on the optical characteristics of WDM multiplexers. In this regard, it is important to study this dependence, which includes measuring the parameters of optical isolation and insertion loss. The purpose of the study is to work out the manufacturing technology and investigate the manufactured WDM multiplexers based on certain types of bend-resistant OF.Methods. For the formation of two-channel WDM multiplexers, the technology of fused biconical tapering was used, which makes it possible to achieve low insertion loss along with a high degree of channel isolation in the wide temperature range.Results. In the paper, the possibilities of manufacturing fiber multiplexers based on bend-resistant fiber Corning SMF-28 Ultra were discussed. The results of manufacturing and studying the experimental samples of WDM multiplexers optical characteristics were presented. It was established that the use of SMF-28 Ultra quartz fiber made it possible to significantly reduce the deviation of the channel optical isolation in the event of mechanical stresses in the multiplexers OF structure. Conclusions. The possibility of creating two-channel multiplexers with low bending losses and optical isolation up to 20–22 dB was experimentally shown. Possible mechanisms of the influence of the multiplexer fiber twisting on the optical isolation of channels were considered. The results obtained showed that when mechanical stresses in the fused structure of the multiplexer occur, the change in the optical isolation coefficient at two operating wavelengths does not exceed 1 dB.

Mathematical delay model based on QS with hyperexponential and Erlang distributions

This article is devoted to the study and obtaining a closed-form solution for the average delay of claims in the queue for a queuing system formed by two flows with hyperexponential and Erlang distributions of intervals. The combination of these distribution laws provides the coefficient of variation of the input flow intervals large units, and for the service time - less than unity. Considering the coefficients of variation as numerical characteristics in the queuing theory is important, because the main characteristic of the queuing system is that the average delay is related to these coefficients of variation by a quadratic dependence. In queuing theory, studies of G/G/1 systems are relevant due to the fact that they can be used in modeling data transmission systems for various purposes. To solve the problem posed, the method of spectral decomposition of the solution of the integral Lindley equation was used. This method made it possible to obtain a spectral decomposition, and through it a solution for the average delay of requests in the queue for the system under consideration in a closed form. For the practical application of the results obtained, the method of moments of the theory of probability was used.

MODELING COMMUNICATION SYSTEMS TO STUDY THE EFFECT OF INTERFERENCE IN THE TRANSMISSION MEDIUM

Context. The problem of creating a model of transmission and transformation of information has been resolved, the processes of information transformation in transmitters and receivers have been considered, the process of influence of the destabilizing factors in the communication channel has been investigated. Objective. The study aims to create a mathematical model of the communication channel, taking into account the destabilizing factors that affect the transmission channel and control the correctness of the communication channel model. Method. A mathematical model, which evaluates the stability of the signal in the communication channel at the stage of designing telecommunication systems for various purposes, taking into account the effects of destabilizing factors in the environment of information signal transmission, is proposed. It is also a proposed method of determining the parameters of information signals in the communication channel and the increase in the bandwidth during exposure of external destabilizing factors on the signal transmission medium in the communication channel. Results. A mathematical model of the communication channel was obtained, which takes into account external destabilizing factors that can affect the communication channel and equipment. The developed model contains a method of verification, which allows determining its correctness. Conclusions. The method of information transfer has been improved by adding a verification method. The value of the bit error obtained during the simulation of the communication channel coincides with the value of the bit error during the verification process, which indicates the correctness of the considered mathematical model of the communication channel. The modeling of the communication channel confirmed the adequacy of the proposed method of modeling the communication system, so this method can be recommended for use in the design and research of telecommunications systems.