Frequency multiplexing (OFDM) methods have become the main basis for most outbred systems. These methods have also found application in modern systems of low-orbit satellite Internet (LOSIS). For example, the StarLink system uses OFDM transmission systems that use a signal frame consisting of 52 channels to transmit data. One way to increase the data rate in OFDM is to replace the Fourier transform (FT) with a faster orthogonal transform. As such, the modified wavelet transform (MWT) of Haar was chosen. The Haar MVP allows to reduce the number of arithmetic operations during the orthogonal signal transformation in comparison with the PF. The use of integer algebraic systems, such as Galois fields and modular residue class codes (MCCR), makes it possible to increase the speed of a computing device that performs orthogonal transformations of signals. Obviously, the transition to new algebraic systems should lead to changes in the structure of OFDM systems. Therefore, the development of structural models of an OFDM transmission system using the Haar MWP in the Galois field and the ICCM is an urgent task. Therefore, the aim of the work is to develop structural models of wireless OFDM systems using a modified integer discrete Haar transform, which can reduce the execution time of the orthogonal signal transformation. And this, in turn, will lead to an increase in the data transfer rate in the SNSI.
Keywords: orthogonal frequency multiplexing, modification of the Haar wavelet transform, structural models of execution of the Haar MVP, Galois field, modular residue class codes
The article presents the results of a full-factor experiment and analyzesthe impact of various factors, such as the number of transitions a tape machine, the characteristics of an infrared laser diode and a the humidity of the material on the magnitude of the signal response when infrared radiation passes through the tape.
Keywords: fiber mixing quality, infrared estimation method, planning matrix, regression equation, model adequacy
The article proposes new compositions of a fast-hardening concrete mixture using Portland cement, fine and coarse aggregates, basalt fiber, a complex modifying additive including acetone-formaldehyde resins and magnesium chloride (bischofite). The results of scientific and experimental studies are presented and the influence of the proposed additives on the formation of the structure, rheological and physico-mechanical properties of fast-hardening concrete is determined. Analysis of the test results showed that the proposed formulations, including a complex additive and basalt fiber, contributed to a decrease in the water-cement ratio, increased mobility of the mixture and increased strength of hardened concrete in the early and final hardening periods.
Keywords: concretes, oil and gas storage, modifying additives, fiber, mobility, setting time, strength
As the number of low-orbit satellite constellations (LEOs) increases, the probability of destructive impact from alien spacecraft (SC) will increase. One of the most effective impacts on the NHS is the setting of relay interference, which is an intercepted and delayed signal. This problem can be eliminated by using the "friend or foe" identification system for the spacecraft. At the same time, in order to reduce the probability of selecting the correct transponder signal by a foreign spacecraft, it is proposed to reduce the time spent on calculating the status of the satellite through the use of parallel calculations using codes of the polynomial residue number system (PRNS). A characteristic feature of these codes is the independent and parallel execution of calculations based on the bases of the PRNS. However, this property of the PRNS code can also be used to correct errors that occur during the operation of the identification system. In this case, the algorithm must perform this procedure at a lower time cost. Therefore, the modification of the error correction algorithm, which makes it possible to provide a higher speed of searching and correcting errors, is an urgent task. The purpose of the work is to reduce the time spent on the execution of the procedure for detecting and correcting errors during the operation of the identification system, by modifying the correction algorithm based on the Chinese residual theorem
Keywords: satellite identification system, codes of the polynomial residue number system, positional characteristic, error detection and correction algorithms
The paper considers mathematical models obtained on the basis of experimental studies of electrical sheet steel. The models reflect the error in determining the main magnetization curve of electrical steel. The magnetic properties are determined in the center and at the edge of the cut of sheet samples with a size of 150 × 150 mm, made by cutting with guillotine shears and laser cutting. The choice of scale factors for calculating the main magnetization curve with an error of ± 5% according to the measured Weber-ampere characteristic has been substantiated. The study was carried out using a device for express control of the magnetic characteristics of electrical sheet steel. The main curve of magnetization of the sample material from sheet electrical steel was determined in an alternating magnetic field with a frequency of 50 Hz, along the direction of rolling. Investigated samples of isotropic sheet electrical steel grade 2212.
Keywords: mathematical model, electrical steel, magnetic properties, magnetization curve
This article considers the option of using a simulation model in organizational conflict management as an intelligent analyzer of a conflict situation. It is proposed to build its own style of leadership, necessary and sufficient to successfully overcome the organizational conflict. Based on the model forecast, the manager constructs an appropriate solution within the framework of the variability of authoritarian, democratic and liberal styles of government with the help of the auxiliary variables available to him. This allows him not only to get out of the usual style of leadership, but also to choose the necessary and sufficient style in this case, to test style behavior strategies. The manager has the opportunity to use the management style that best suits the internal and external conditions of his activities. Today, managers must meet the emerging problems and the ability to solve them effectively with their stylistic variability.
Keywords: simulation model, conflict in the organization, management style, behavior strategy, manager
The article deals with current methods of evaluating the organization and management in construction under conditions of uncertainty. The typology of the failure process is given, which determines the scenario of the crisis development at the enterprise. A model of forecasting and management in a crisis is proposed, and the conceptual aspects of building this model are considered. It is proposed to improve the enterprise management system based on the analysis of the economic component as a temporary function. Recommendations are given for improving the existing organizational forms of enterprise management.
Keywords: construction organization, organizational and technological solutions, reliability assessment, construction quality assessment
Questions of accounting of actors of influence on the investment and construction cycle are raised. An example of the use of BIM-technologies in construction is considered. It describes the solution of some specific problems that arise when maintaining the quality of construction of complex buildings, taking into account the possibility of introducing modern information systems, attention is paid to the peculiarities of improving the quality of work performed.
Keywords: organization of construction; quality of design, quality of construction and installation works, BIM-technology
Organizational conflicts are a natural and integral part of any process. In modern control theory, it is proposed to use various adaptive control structures to solve such problems, in particular, with reference or configurable models in the control loop. A cognitive model of adaptive management of organizational conflicts with a configurable model in the management loop is considered. Embedding the model in the control loop allows you to integrate information about the dynamics of process characteristics. Based on information processing, a variant of controls for de-escalation of the conflict is proposed. The model in the organizational conflict management loop is essentially an intelligent conflict situation analyzer. It presents options based on the accumulated and processed information within the framework of known precedents for their solution. The core of such analyzers is a simulation model based on the system dynamics paradigm. The built simulation model allows you to evaluate and predict the impact of factors, ways to stabilize and manage organizational conflicts, taking into account the main parameters. In accordance with the concept of adaptive management, the model can be configured for the current values of the conflict situation parameters and, in accordance with the already tested options, can offer management in a specific situation. The use of the system dynamics paradigm in the model for building an effective forecast is focused on the strategic level of management.
Keywords: cognitive model, simulation model, conflict, escalation, contour, management, de-escalation, organization
The directions of modern research in the field of adaptive error correction, which can be applied when transmitting images in JPEG 2000 format over a noisy channel, are examined. Adaptive correction at the network level allows you to maintain a given percentage of packet delivery. Uneven protection at the application level is intended for use in broadcast broadcasts and allows the consumer to receive an image of various quality depending on the state of the network. Adaptive uniform protection at the application level is focused on point-to-point transmission and is aimed at receiving the maximum image quality by the receiver. The network layer tools discussed can be combined with the application layer tools.
Keywords: adaptation, noise-proof coding, forward error correction, noisy channel, JPEG 2000
The work is devoted to the structural characterization of carbon nanotubes by means of electronic combination scattering of light. Samples of double-walled carbon nanotubes with various electronic configurations of the layers have been synthesized, their study has been performed by means of high-resolution transmission electron microscopy, electron diffraction, Rayleigh spectroscopy, as well as spectroscopy of combination scattering of light. The structural characterization of the synthesized nanotubes has been carried out using electronic combination scattering of light, which can play the role of an additional criteria for nanotubes indexing, helping to clarify and verify the obtained results.
Keywords: carbon nanotubes, catalytic chemical vapor deposition, spectroscopy of combination scattering of light
The mining industry, as well as the socio-economic development of this sector, makes a significant contribution to the development of the economy of some low-and middle-income countries rich in non-fuel minerals, as evidenced by the modified mining contribution Index (IVGP-BP). 10 of the 20 countries in which the mining industry contributes the most (the highest GPI-BP) rose one or two positions higher, according to the world Bank's country classification, between 1999 and 2019. Based on detailed data from the mining sector, such as mining, exports, prices, rents for mineral resources, mineral exploration expenditures, and state budget revenues, the current situation for 2019 is analyzed, as well as trends regarding the contribution to the development of the socio-economic level of the mining industry for 1999-2019.
Keywords: mining, minerals, industry, economy, export, mineral rent, gold, coal
The modern world is impossible to imagine without means of technical movement, broad mechanization and automation of production processes. Mechanisms exude harmful noises and vibrations that adversely affect the human body. Many materials have been created that absorb harmful noises and vibrations. Vibrating materials are widely used in everyday life. They are applied to the parts of cars, hulltrains of trains and aircraft from the inside. Anti-corrosion coating helps to protect the bottom of the car and train. It can serve as another level of protection against noise and vibration. At the heart of the vibrating material, as in the anti-corrosion coating, is a viscous layer, which, in turn, is modified by the introduction of fillers and plasticizers. The difference between vibrating material and anti-corrosion material is that for a greater increase in its vibrating properties, the material is sometimes reinforced. The article presents the results of studies of the mastmaterial material with such fillings as mica ground flogopit SMF-123, calcium formiat, melflux 1641F, melflux 4930F, melflux 6681F. A steel plate with a mast material applied to it has been selected as the object of the study. The matrix material was based on polyninilacetate, which injected epoxy resin and dibutylphthalate. The loss factor of the material was determined by a resonant method, the essence of which is to excite the sample of cross-range oscillations. Developed vibrating mastics, selected effective fillers and plasticizer for it. The dependence of vibrating properties on the amount of epoxy resin injected, plasticizer and the influence of thickness of layers is represented.
Keywords: polyvinyl acetate, epoxy resin, vibration-absorbing mastic material, damping, loss coefficient
Within approaching the plane-stress state the problem of a high-speed rotating disk being under side pressure is considered. Within the model of a perfect rigid-plastic body and the Mises yield criterion the values of external parameters for which the plastic zones appear have been defined. The stresses in plastic zones are obtained from the solution of the Cauchy problem, which includes two differential equations to define the stress tensor nonzero component. In order to estimate the stress state in the elastic zone the equivalent stress is introduced. The maximum allowable values of external parameters are obtained from the solution of the problem when the disk is in the limit state. The numerical results are represented as the stress vector hodograph.
Keywords: the plane-stress state, Mises yield criterion, the equivalent stress, an elasto-plastic solid, a rotating disk, a stress vector hodograph
Finite state machines, being a mathematical abstraction, allow you to perceive information from the control object, process it and give signals to control the object. The disadvantages of the representation of complex production systems by a set of finite state machines include the complexity of carrying out logical and set-theoretic operations on them and the complexity of describing the parallelism that occurs in the operation of complex production systems. When specifying a finite state machine in the matrix–predicate form, due to the information redundancy, it is possible to avoid these difficulties. Matrix–predicate method allows you to uniquely set the finite state machine square matrix, which makes it possible to use the methods of the theory of matrices during the set–theoretic operations on them and it is possible to avoid isomorphism. The paper presents the developed methods of representation of a finite state machine using a multi-place predicate, which greatly simplifies its task.
Keywords: finite state machine, graph, matrix, predicate, algorithm, matrix–predicate method, graph incident, tuple, Cartesian product, complex production systems