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In the introduction, the authors argue the relevance of the researched problem of improving the algorithm for estimating transaction cost of bank’s purchase and sale in the Russian financial services market. It is emphasized that the need to manage the value of a commercial enterprise arises not only when planning the purchase and sale transaction of the entire business or part of it. The valuation is taken into account, first of all, when corporatizing an organization, attracting new shareholders, insuring its property, obtaining a loan secured by property, calculating the fair value of taxes.The first part of the paper substantiates the business valuation algorithm intended for a potential investor and adapted to the conditions of the Russian financial market. This takes into account the specific features of each bank in question. Based on the data from open financial statements (for 2017–2022), the parameters required in the procedure for obtaining estimates are calculated.The second part of the paper presents the result of selecting indicators of the external and internal economic environment of banks that have a significant statistical relationship with the resulting valuation. The selected factors are under the control of managers and can be used to guide the proposed cost estimate. Data were obtained on the direction and strength of influence of selected factors on the value of business. The selection algorithm is based on mathematical modeling using bank data for the period under consideration.The valuation is based on a comparative approach, where the values of the multiples are calculated using a linear regression model. To organize cost management, a panel regression model is built, which allows to select significant financial indicators and determine the nature of their impact on the bank's value.

The ability to attract foreign direct investment (FDI) is a critical success factor for the development of any participant in the local market. One of the indicators that characterize the investment attractiveness is the economic value added (EVA). It reflects the market assessment of the company's profit potential. Some EVA assessment methodologies include the country risk assessment – a factor that is beyond control. This study analyzes the impact of this indicator on the investment attractiveness of an organization. The authors estimated the economic value added for some of the largest Russian companies using methodologies that take into account the country's risk level, as well as those methodologies that do not take it into account. The calculations used adjustments for EVA in line with specific features of Russian accounting. As a result, it was revealed that, regardless of industry affiliation, the investment attractiveness of Russian organizations decreases when the country's risk factor is included in its assessment.The article justifies the relevance of the developed approach to the assessment of investment attractiveness of companies based on country risk level as a factor that impacts the ability of organizations to generate profit, making it possible to detect hidden management problems. According to the authors, the application of this approach not only contributes to the solution of long-term and medium-term tasks of business development (for example, the creation of its infrastructure) but also greatly facilitates the entry of organizations into international markets.One of the authors' conclusions of the study is that using the methodological tools developed by them for analytical purposes requires improving the management of the investment attractiveness of an organization and, consequently, its objective assessment. The structure of economic value added can serve as a basis for making management decisions related to increasing investment attractiveness. According to the authors, the provisions formulated in the article can serve as a methodological guide for organizing business valuation based on the EVA in the Russian context. Results of the study can be of interest to managers, current owners of companies, and potential investors.

Severe complications of COVID‑19 are pneumonia and the development of acute respiratory distress syndrome, which is accompanied by hypoxia. Tissue hypoxia increases against the background of inflammatory reactions and hypercoagulation. Hyperbaric oxygenation can effectively reduce systemic hypoxia, improve blood circulation, has a beneficial effect on reducing the severity of the inflammatory condition by modulating oxidative stress, including lipid peroxidation, and increasing antioxidant enzymes. A review of clinical studies conducted in different countries shows the overall effectiveness of systemic maintenance therapy with the inclusion of hyperbaric oxygenation, which reduces the use of artificial ventilation and reduces the mortality rate of severely ill patients with COVID‑19. The article presents the results of our own research on the rehabilitation of 10 patients who had a severe form of COVID‑19. The inclusion in the rehabilitation of COVID‑19 patients of daily sessions of hyperbaric oxygenation in ‘soft’ modes (1,4–1,6 ATA) in combination with respiratory and physical gymnastics showed a positive effect and safety. In patients, shortness of breath decreased, blood saturation indicators improved, cognitive functions decreased, the severity of anxiety and depression decreased, and exercise tolerance increased.

The article describes a new learning programming environment that makes it possible to control Robot, Aquarius, and Turtle virtual robots by means of Blockly visual programming language. The environment is a set of freely available web applications hosted in Internet. Such an approach provides for workability under all modern browsers both on desktop computers and mobile devices. Automatic verification of the correctness of problem solutions is available for all the virtual robots. Suboptimal solutions that use excessive number of blocks receive a lower score due to the rating system (from one to five "stars"). Offline version is available, which can work in local mode without access to Internet. Users can develop and distribute their own sets of problems for all virtual robots.

Background. Due to the prevalence of Vitamin D deficiency as well as the frequency of reconstructive surgical interventions followed by dental implantation, the issue arises concerning the effect of Vitamin D on reparative regeneration of bone and osseointegration of dental implants. The purpose — using literature data we are conducting an impact assessment of vitamin D on reparative regeneration of bone tissue, in particular, after oral reconstruction surgeries and dental implantation. Methods. Retrieval, systematization and analysis of scientific data on application of vitamin D supplementation and its effect on reparative regeneration of jaw bone tissue. The conclusions. For the most part, the positive effect exerted on reparative regeneration of jaw bone tissue and osseointegration of dental implants is due to the role of vitamin D in physiological processes evolving in bone tissue, namely maintenance of calcium and phosphate exchange through intestinal absorption and TNF α , RANKL (Receptor activator of nuclear factor kappa-B ligand) and consequently differentiation of precursors to osteoclasts into osteoclasts through VDR stimulation (Vitamin D Receptor) – receptors for further osteogenesis. Also, according to literature data, FGF23 (Fibroblast Growth Factor) protein is a marker of osteoblasts differentiation into osteocytes, it is also known that FGF23 and 1,25( ОН )2D3 are genetically related. FGF23 is the main regulator of both phosphate exchange in bones and metabolism of vitamin D and its metabolites. Besides, indirect anti-inflammatory effect has been observed thanks to inhibition of pro-inflammatory cytokine secretion. Taking into account the abovementioned data, of particular relevance is the definition of serum concentration 25( ОН )D and development of schemes of vitamin D level pre-surgery correction in patients, who have to undergo oral reconstruction surgeries and dental implantation. Mass spectrometry is a promising diagnostic method for determining the level of vitamin D in a body, as it allows to identify the actual amount of vitamin D free from admixture of other steroid hormones. The introduction of this method into clinical practice will allow to monitor the level of vitamin D in patients, receiving reconstructive and rehabilitative treatment.

This publication reflects the results of the authors’ research aimed at finding ways to reduce the complexity of appraising the investment attractiveness of potential recipients of investments. The purpose of the research is to create a methodology that will effectively manage not only the process of determining the recipients of investments but also the development of organizations to increase their investment attractiveness. The authors provide an overview of the most significant publications that consider existing methods for appraising investment attractiveness, based on both financial statements and the market value of a business. In the main part of the article, the authors conclude that data envelopment analysis (DEA) may be used to aggregate several different criteria of the investment attractiveness appraising in one number. The section that presents the empirical results of the study contains a description of a number of indicators of Russian oil refining companies and their aggregation based both on the method of expert assessments and a formal approach using the DEA. The examples only apply criteria calculated based on organizations’ financial statements. It is emphasized that in real practice the first method is a very expensive and time-consuming procedure in comparison with the second, which provides a formalized agreement of the criteria used in the former method, and takes into account the situation in the entire market segment under study. It is shown that the calculations made based on these two methods give approximately the same results. This indicates that the methodology proposed by the authors can be considered as an effective alternative to existing expert approaches to appraising investment attractiveness. In the final part of the article, recommendations are formulated for improving the proposed methodological approach by including a number of market indicators that characterize the activities of potential recipients of investments.

The article proposes to take a fresh look at the traditional for any informatics course material, which describes the fundamental principles of number representation. It considers in details the ideas how different number notations are formed; special attention is paid to the problem related to the amount of numerals used for presenting values in every digit. It is shown that frequent in school informatics definition of radix as an amount of numerals that employed in a system becomes incorrect under careful review. For those who want to discuss this problem at a lesson, two ways are possible: one (stricter) is founded on mathematical formulas, and another is based on a generalization of various notation examples; both methods are presented in the article. Besides for demonstrative narrating of the material to pupils the authors designed their own analogy, which facilitates understanding of the topic. Practical application of notations to computer technique is also discussed.

The paper studies the effect of drag reduction in a two-medium boundary layer due to sliding at the interface region. The results obtained by authors in the framework of the boundary layer theory are in good agreement with those obtained by integrating the continuum equations of motion for film flows in the ANSYS Fluent package with reduction of computational time for the first case.

The article presents an analysis of problems that arose in informatics education due to introduction of State Final Attestation in the form of Unified State Exam (USE). Some measures are proposed to overcome the shortcomings of existing systems for evaluating results of education.

The paper presents a mathematical model of the film flow over a half-plane directed at an angle to the horizon. In the cross section of the film, a quadratic law for the longitudinal velocity distribution is adopted, taking into account friction on the film surface. An approximate solution of the problem is obtained in the form of a series in powers of the small parameter. The solution is presented in the form of graphs of the film thickness and the average longitudinal velocity along the length of the plate.

The numerical dynamic model of a ball-bearing with angular contact and oil lubricant, which allows to study movement of the bearing parts, having six degrees of freedom, is developed. The general parameters, characterizing loading of bearing retainer, are analyzed. The influence of general structural parameters of several ball-bearings on in-service operation conditions of their retainers is analyzed.

The paper investigates the influence of the process of running-in the ends of rollers and sides of cylindrical roller bearings on the conditions of hydrodynamic contact of these parts: the formation of an oil film and friction. For this purpose, the results of finite element modeling of the stress-strain state of the bearing parts in contact: the inner ring, the side flange and a fragment of the axle of the wheelset, and the multi-mass simulation of the dynamics of the bearing operation are used. The influence of the yaw angle of the roller on the size and shape of the contact area on the side is investigated. The dependences for calculating the thickness of the oil film in the contact between the ends of the rollers and the flanges of the bearing rings are being refined, which now make it possible to take into account the misaligned position of these parts during their force interaction. The results are illustrated using the example of a roller bearing of standard size 232926.

We investigate the prompt emission and the afterglow properties of short-duration gamma-ray burst (sGRB) 130603B and another eight sGRB events during 2012-2015, observed by several multiwavelength facilities including the Gran Canarias Telescope 10.4 m telescope. Prompt emission high energy data of the events were obtained by INTEGRAL-SPI-ACS, Swift-BAT, and Fermi-GBM satellites. The prompt emission data by INTEGRAL in the energy range of 0.1-10 MeV for sGRB 130603B, sGRB 140606A, sGRB 140930B, sGRB 141212A, and sGRB 151228A do not show any signature of the extended emission or precursor activity and their spectral and temporal properties are similar to those seen in case of other short bursts. For sGRB 130603B, our new afterglow photometric data constrain the pre-jet-break temporal decay due to denser temporal coverage. For sGRB 130603B, the afterglow light curve, containing both our new and previously published photometric data is broadly consistent with the ISM afterglow model. Modeling of the host galaxies of sGRB 130603B and sGRB 141212A using the LePHARE software supports a scenario in which the environment of the burst is undergoing moderate star formation activity. From the inclusion of our late-time data for eight other sGRBs we are able to: place tight constraints on the non-detection of the afterglow, host galaxy, or any underlying 'kilonova' emission. Our late-time afterglow observations of the sGRB 170817A/GW170817 are also discussed and compared with the sub-set of sGRBs.© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society, AJCT acknowledges support from the Junta de Andalucia (Project P07-TIC-03094) and support from the Spanish Ministry Projects AYA2012-39727-C03-01 and 201571718R. This work has been supported by the Spanish Science Ministry 'Centro de Excelencia SeveroOchoa' Program under grant SEV-2017-0709. FEDER funds are acknowledged. E.S. acknowledges assistance from the Scientific and Technological Research Council of Turkey (TUBITAK) through project 112T224. We thank TUBITAK for a partial support in using T100 telescope with project number 10CT100-95. A.S.P acknowledges partial support grants RFBR 17-02-01388, 17-51-44018, and 1752-80139. E.D.M., A.A.V., and P.Yu.M. are grateful to RSCF grant 18-12-00522 for support. B.-B.Z. acknowledges support from National Thousand Young Talents program of China and National Key Research and Development Program of China (2018YFA0404204). R.Ya.I. is grateful for partial support by the grant RUSTAVELI/FR/379/6-300/14. R.S.R. acknowledges support from ASI (Italian Space Agency) through the Contract No. 2015-046R.0 and from European Union Horizon 2020 Programme under the AHEAD project (grant agreement No. 654215). SJ acknowledges the support of the Korea Basic Science Research Program through NRF-2015R1D1A4A01020961.

The main problems encountered in attempting to optimize the control of electrotechnical complexes used to make nonwovens are identified. The dynamic characteristics of a dual-channel system for controlling the transport and winding of nonwovens are examined on a “Reicofil” unit with allowance for the deformation properties of the fibrous product. The article also presents the main principles behind the planning and design of complex dynamic objects with the use of neural networks.

The main trends in optimizing the control of electrotechnical equipment used to make nonwovens are examined. The basic principles behind the use of modern theories and methods of mathematical modeling to plan and design complex dynamic systems are discussed. The article looks at promising developments in the creation of intelligent systems to form, transport, and wind fibrous materials. These systems save energy while allowing high-speed operation of the production equipment.

Substitution of mandibular defects resulting from injuries and inflammatory bone diseases as well as surgical interventions for tumors is an important medical and scientific problem. The article presents the results of surgical treatment of 8 patients with the use of combined endoprosthesis of the mandible consisting of individual titanium metal structure and titanium silk. This solution provides the possibility for reliable fixation of the soft tissue structures of the lower face region by suturing, including facial and masticatory muscles, improving the biological integration of the endoprosthesis. The combined design shows high efficiency of restoration of both aesthetic and functional characteristics of the mandible, as well as good long term survival rate.Замещение дефектов нижней челюсти, возникающих в результате травм и воспалительных заболеваний кости, а также оперативных вмешательств по поводу опухолевых процессов, составляет важную медицинскую и научную проблему. В настоящей работе показаны результаты хирургического лечения 8 пациентов с применением комбинированного эндопротеза нижней челюсти, состоящего из индивидуальной титановой металлоконструкции и 'титанового шелка'. Данное решение обеспечивает возможность надежной фиксации мягкотканных структур нижней трети лица путем их подшивания, в том числе мимических и жевательных мышц, улучшая биологическую интеграцию эндопротеза. Комбинированная конструкция показала высокую эффективность восстановления как эстетических, так и функциональных характеристик нижней челюсти, а также хороший уровень 'выживаемости' эндопротезов в отдаленном периоде наблюдения.

In patients with drag-induced jaw osteonecrosis which developed in cancer patients due to administration of bisphosphonates for metastases, the microflora of the oral cavity was examined by chromatography-mass spectrometry (HMS). The method of HMS can be used as an additional method of diagnostics in complex clinical cases with ineffective treatment.При медикаментозном остеонекрозе челюстей, развившемся на фоне приема бисфосфонатов, назначаемых по поводу метастазов онкологическим больным, исследовали микрофлору полости рта методом хромато-масс-спектрометрии (ХМС). Метод ХМС может быть использован как дополнение к основным методам диагностики в сложных клинических случаях и при неэффективности лечения.

The results from investigating the magnetic and magneto-optical properties of Fe–Ti–O composite films with compositions above the percolation threshold, prepared via a solid-phase reaction with oxygen exchange in layered FeO/Ti structures, are presented. Features of the magneto-optical spectra of prepared films are compared to the spectra of continuous metal films.

The main stages in the process of formalizing and mathematically describing the dynamic regimes of energy-intensive electromechanical systems are determined. Optimality criteria are proposed to reflect specific features of certain machines used in the production of chemical fibers and filaments. A classification is presented for optimization problems and methods of solving them. The maximum principle is used as a basis for solving static and dynamic problems involving optimization of the speed regimes of energy-intensive equipment used to make nonwovens. The problems are solved with allowance for constraints on the parameters of the given system.

A modernized method is proposed for controlling the lapping and winding of nonwovens. A functional diagram is created for a modernized control system along with an algorithm for operation of the system’s control microcomputer, the algorithm providing for special and startup regimes. Another algorithm is proposed for starting the electric drive of the conveyor of the heating chamber based on tracking of the linear density of the laps. The effectiveness of the control algorithm is demonstrated on a laboratory stand that was developed to model equipment used to control lapping and winding.

Partial modernization of the system for automatic control of the process of feeding and producing a fibrous product into the self-weight of a Befama CS-412 carding machine has been accomplished. An improved functional system for control of high-speed carding lattice operation regime, which ensures the set technological procedures, has been developed.

The structure of a mechanical model of fibre material spun in the free zone of a unit for production of nonwovens is proposed. The deformation zone is analyzed with the electromechanical analogies method. A mathematical model of the deformation zone of the fibre product is represented as the object of automatic regulation corresponding to the direct analogy of the physical system of spinning, transport, and winding. The deformation zone was investigated for stability and the presence of auto-oscillations. Parametric optimization of the conditions of transport of the fibre material was performed to obtain satisfactory quality of the transitional process and minimum extremum of the functional of the process parameter.

A new approach to modeling of the work performed by cone drill bits at the face is outlined. A virtual model of the dynamic force interaction between a cone drill bit and the face of the hole is proposed. The ADAMS software package is used for the modeling with consideration of frictional forces in the sliding supports, the frictional forces of the equipment components, and the depth of their embedment in the rock. The dynamic forces acting on the teeth during rotation of the cutters, and the distribution of average loads around the rings and cutters of the bit are obtained. The possibility of using the model developed to optimize parameters of bit equipment is demonstrated.

The problem of the optimal estimation of continuous processes by discrete measurements in the presence of time lag (delay) is considered. On the basis of the theory of parametric transfer functions, an optimal, periodically nonstationary filter is developed, which affords a minimum of the estimation error variance at any instant of time. The comparison is performed of the obtained solution with the optimal stationary filter, which ensures a minimum of the mean (by continuous time) error variance. It is shown that in the problem of estimation of the Markov process of the first order, a simpler stationary filter with the fixer of order zero is insignificantly inferior to the optimal filter.

The conditions that function We(z), which ensures the minimum acceptable time of the switching process, must satisfy can be formulated as follows: — function We(z) should have nulls equal to the poles of Wn(z) positioned in the unit circle or outside of plane z; — function W(z) or 1 — We(z) should have all nulls of Wn(z) located in the unit circle or outside of plane z as nulls; — function W(z) or 1 — We(z) should contain z−1 as cofactor z−1. If Wn(z) is an unstable unit impulse response, then F(z) should contain all poles of Wn(z) lying in the unit circle or outside of plane z as nulls (with the exception of the poles for z = 1). If Wn(z) has nulls located in or outside of the unit circle, these nulls must be nulls of W(z) = 1 − (1 − z−1). In these two cases, the briefest time of the switching process will exceed the value which can be obtained for a system with a stable unit impulse response Wn(z) which has no nulls in or outside of the unit circle of plane z.

Three-parameter and four-parameter models of mechanical systems were analyzed to assess the physicomechanical properties of polymer materials. An electromechanical analogy method was developed for characterizing the physicomechanical properties of polymer and fibre materials; one feature of the method is the physical directivity, i.e., representation of the elements of mechanical systems in the form of equivalent electrical circuits. The quadrupole method was used for creating electrical models of the mechanical systems examined, which consisted of elastic, inertial, and friction elements.

The problem of synthesizing ℋ2-optimal digital control law for a continuous plant with multiple delays is considered. An equivalent discrete system, whose stability and optimality conditions coincide with the corresponding conditions for the initial digital system is constructed. An efficient computational algorithm for constructing the implementation of the equivalent discrete model of the plant in the state space is proposed.

The problem of digital stabilization of continuous plants whose models consist of several blocks of pure input and output delay is considered. A discrete-time model of the closed loop is constructed, and its stability is proved to be equivalent to the stability of the hybrid sampled-data system. The necessary and sufficient stabilizability conditions of the continuous plant with a generalized hold element are obtained.

Singular $$\mathcal{H}$$ 2-optimization problems are considered for the standard discrete-time control system. Two types of singularity (type I and type II) are distinguished. A detailed treatment of problems with singularity of type II, which leads to nonuniqueness of solution, is presented. New algorithms for design of optimal controllers are presented both in frequency domain and state space, which generalize standard procedures onto the case of singular $$\mathcal{H}$$ 2-problems. A parameterization of the set of optimal controllers is given.

The problem of improving the quality indices of nonwovens is examined and is solved by optimizing control of the speed regimes of the electromechanical systems used in their production. The use of a multi-motor electric drive in combination with monitoring of the physico-mechanical properties of the fibrous product during the various conversions makes it possible to correct the speed regimes of the machines in the flow line. The authors construct and analyze a functional model of a modernized control system for an automated line designed for the production of bulk nonwovens. Technical solutions for optimizing control of the complex’s high-speed operating regimes are presented to illustrate the use of the model.

A direct method for robust sampled-data tracking systems design is presented. The method is based on the use of Laplace transformation in continuous time and polynomial equation theory. A criterion is proposed for robust optimization of sampled-data tracking systems. The structure of the optimal robust controller transfer function is investigated and its order is determined explicitly. The relations between robust and quadratic optimization problems are established. A mixed optimization problem is considered, when the cost function includes the integral quadratic error and a robustness term.

A method is presented for synthesis of optimal sampled-data tracking systems with two controllers, one of which is incorporated into the closed loop, while another is placed in feedforward chain. The approach is based on Laplace transform in continuous time and polynomial equations theory. The set of all admissible reference controllers is constructed. The cost function include integral quadratic output and control errors in continuous time.

Consideration is given to a mathematical model of the nonseparating nonstationary motion of an ideal compressible gas in a pipeline with a variable cross section. A method which enables one to calculate changes in the pressure, density, and the velocity at the sites of contraction and expansion of the pipeline without going beyond the scope of a one‐dimensional model is presented.

A method of optimal design of digital tracking systems for continuous-time plants is presented. The method is based on the use of Laplace transformation in continuous time and polynomial equation theory. The cost function employed for quadratic optimization takes system performance in continuous time into account. The structure of optimal digital controller transfer function is investigated and its order is determined explicitly. The possibility of designing optimal tracking system for a neutral plant is analyzed.

A concept for building the structure and studying controllable electrotechnical complexes for manufacturing equipment that increase the efficiency of saving energy and resources by optimizing the speed regimes is proposed. Selection of the velocity diagram of transportation, spinning, and winding of synthetic fibres and nonwovens should precede the process study to determine the optimum regime indexes.