Subject of Research. The work deals with the technique for shaping of the polished substrate surfaces for interference mirrors of gas lasers, laser gyro sensors, in particular. The main attention is paid to the manufacture of parts from optical SO-115M sitall with a given curvature of the central zone and a flat surface of the peripheral ring, designed for installation on a laser resonator monoblock body by means of an optical contact. Method. The required shaping result was achieved by grinding and polishing of products in the presence of metered local mechanical stresses applied to the membrane in the central zone of the substrate. At this, the profile parameters were monitored using phase shifting interferometry technique. The experimental results were compared with the data of mathematical modeling by applying an engineering program for finite element analysis. Main Results. The main dependences of the curvature radii of spherical surfaces obtained in the technology under consideration are specified for various values of mechanical loads and geometric parameters of membranes. Particular attention is paid to consideration of the maximum stress values in the samples and their comparison with the ultimate strength characteristics of the material. It is shown that the considered technological approach can be effective in the manufacture of substrates for interference mirrors of gas laser resonators, including sensors of laser gyroscopes. In addition, the described technology can be used to manufacture aspherical substrate surfaces. Practical Relevance. The method considered provides for increase of the optical parts processing productivity in conditions of mass production.

Subject of Research.The paper presents experimental results of the chemical etching duration impact on the tilted fiber Bragg grating transmission spectrum. The goal of this research is the sensitivitygrowth of the tilted fiber Bragg grating aimed at its application as an element of fiber optical sensor for refractive index ofliquids measurements. Method. The chemical etching was performed in the 50 % hydrofluoric acid solution. The chemical etching duration was 5, 10, 15, 20 and 30 minutes with pauses for spectra measurements. The spectrum of the tilted fiber Bragg grating was measured at every research step in the media with various refractive index. Main Results. The sensitivity estimation of the tilted fiber Bragg grating to the variation of refractive index is performed. The decrease of the optic fiber thickness as a result of chemical etching leads to lower responsivity of the sensor Practical Relevance. Experimental research shows that chemical etching decreasesthe sensitivity of tilted fiber Bragg grating to the refractive index variation for the medium under study. Analysis of measurement results is applicable in the design and development of concentration optic fiber sensors or solution refractive index of the researched material.

Subject of Research.The paper considers analysis of mechanical and optical properties of modern optical polymer materials. We present the result of design and quality characteristics of small magnification telescopic glasses, made of modern optical polymers and intended for application in medicine, production of microelectronic circuits, and jewelry. Method. Calculation of telescopic glasses is carried out according to Galilei scheme on the basis of the automated method of aberration correction. The requirements are fulfilled concerning the necessity exception of additional accommodation of eyes at transition from observation with and without glasses, due to the object and image location in one plane. Main Results. The obtained optical system has diffraction image quality, and the mass of fully polymer glasses is two times lower than that of analogues made of glass. Practical Relevance. Modern optical polymers have advanced mechanical and optical properties, and create the perspective of glass component replacement with polymer ones and fabrication of fully polymeric optical systems with high quality characteristics. At the same time, manufacturing technologies of components made of optical polymers provides to obtain surfaces of complex shape (kinoforms, aspherics, and “freeforms”). Technical problems can be solved associated with the scaling of production, reducing of the assembly labor intensity, updating of the design, reducing of the mass and dimensional properties, and the cost of products.

Subject of Research. The paper presents a developed method for rapid instrumental assessment of microbial contamination, as well as pro- and antibiotic properties of pharmacological, food and other products. Method. The developed technique consisted in periodic instrumental registration of changes in pH, redox potential, and electrolytic conductivity of a liquid nutrient medium incubated in the presence and absence of viable test microorganisms and test samples. A comparative analysis of the pro- and antibiotic activity of Staphylococcus aureus was carried out at various concentrations of whole subcritical extracts obtained from ten different types of plant raw materials using liquefied carbon dioxide as an extractant. Main Results. The studies carried out have confirmed that the presented method makes it possible to assess the initial microbial contamination more speedily, objectively and informatively in comparison with the standard one as well as the effect of various samples of pharmaceutical, food and other products on the dynamics of the microorganisms’ vital activity. Among the studied samples, the most active prolonged antibiotic properties have been exhibited by extracts from the fruits of Sambucus nigra and Rosa cinnamomea, as well as green leaves of Camellia sinensis at their concentrations in the test medium from 3 vol.% and higher. The most active prolonged probiotic properties have been found in extracts from the Hypericum perforatum herb and green leaves of Camellia sinensis at their concentrations in the test medium equal to 0.2 vol.%. In this case, the biological activity of the tested samples with respect to test microorganisms in the most cases have monotonically decreased with an increase in the interaction time of the mentioned microorganisms and samples. Practical Relevance. The results of this study can find application in the composition development and assessment of the properties of new pharmaceutical, food and other products, including various plant extracts. In addition, the proposed method of instrumental microbiological testing can be applicable for control of microbial contamination, as well as pro- and antibiotic properties of various samples of products already accepted for the usage, and individual ingredients and additives to them.

Subject of Research. The paper considers motion estimation as the most difficult and resource-consuming process in the high efficiency video coding standard. A fast algorithm is proposed that skips the fractional-pixel motion estimation. Method. The fractional-pixel motion estimation, including the half-pixel and quarter-pixel motion estimation, is used as a refinement process for integer-pixel motion estimation to provide better coding efficiency. The proposed algorithm involves skipping the fractional motion estimation for prediction blocks if the block with 2N × 2N dimension, which contains more information than the other block sizes, is encoded with integer motion estimation. The decision can also be made in reference frames, so that motion estimation at half- and/or quarter-pixel levels can be skipped to reduce encoding time. Main Results. The proposed algorithm is implemented in HM-16.20 reference software. Several test sequences recommended by the International Telecommunication Union (ITU) are used to evaluate its effectiveness. Experimental results show that the proposed fast algorithm reduces the encoding time by an average of 64 % with a performance loss of less than 1 %. Practical Relevance. The proposed fast algorithm provides a reduction in coding time with a slight loss in performance. It can replace an existing unit in the H.265 standard speed up the video compression process.

Subject of Research. The joint clustering method in network and correlation context is designed to identify active modules in metabolic graphs based on transcriptomic data represented by a large number of samples. The active modules obtained by this method describe the dynamic metabolic regulation in all samples of the analyzed dataset. The paper presents modifications of the proposed method for application on real data. Method. For results stability study the modified method was repeatedly run on real data with small variations of the initial parameters. For result analysis, several metrics were formulated that display modules similarity and representation under various start-up conditions. Main Results. The analysis results are sufficiently robust. For the most modules, their profiles are detected well in the noisy data, and the most genes are also preserved. Practical Relevance. The results of the presented study have shown that the modified method analyzes successfully real data by producing active modules that are stable and easy in interpretation.

Subject of Research. The paper analyzes the current concept of digital twins in relation to production systems. The review is given for characteristics and parameters of the digital twin that create advantages of using this concept for production systems at their life cycle stages. Technical implementation variants for the concept of digital twins are proposed aimed at improvement of the technological processes of production systems at the following stages of the life cycle: an idea, project, realization, operation, and disposal. Method. We performed a retrospective analysis of scientific papers on the methodology and practical application of software-based approaches to the design, implementation and operation of industrial systems in Industry 4.0. An expert assessment and applicability analysis of the digital twins at the stages of the life cycle of production systems are given. Main Results. The main characteristics of the digital twin affecting the effectiveness of the concept application in production systems are determined and arranged into groups according to their importance based on the analysis of the foreign studies over the past 10 years. The advantages and disadvantages of a software-oriented approach application to the design, implementation and operation of production systems are formulated. Practical Relevance. The digital twin characteristics are determined that affect the efficiency of its usage at the life cycle stages of production systems. Variants of the modern concept technical implementation of digital twins for production systems are proposed by applying of advanced digital technologies and intelligent electronic devices. Requirements are systematized concerning functionality, performance, correspondence accuracy of the virtual and physical environment state, as well as the qualitative characteristics of the digital twin. They provide for the assessment about the applicability of digital twins for solving existing problems of control and management in production systems.

Subject of Research.The paper deals with Bayesian method for hyperparameter optimization of algorithms, used in machine learning for classification problems. A comprehensive survey is carried out about using a priori and a posteriori knowledge in classification task for hyperparameter optimization quality improvement. Method. The existing Bayesian optimization algorithm for hyperparameter setting in classification problems was expanded. We proposed a target function modification calculated on the basis of hyperparameters optimized for the similar problems and a metric for determination of similarity classification problems based on generated meta-features. Main Results. Experiments carried out on the real-world datasets from OpenML database have confirmed that the proposed algorithm achieves usually significantly better performance results than the existing Bayesian optimization algorithm within a fixed time limit.Practical Relevance. The proposed algorithm can be used for hyperparameter optimization in any classification problem, for example, in medicine, image processing or chemistry.

Subject of Research.The paper considers the inferring of gene regulatory networks in the form of Bayesian networks from gene expression data. We present this problem as the problem of the marginal probability estimation for each edge appearance in the true Bayesian network under the known gene expression levels. Monte Carlo approach based on the Markov chains is proposed. Method. The proposed method involved the sampling of Bayesian network pairs and a discretization policy, providing a way for the network to be applied to continuous gene expression dataaccording to a posteriori distribution. The Markov chain Monte Carlo approach was used for sampling with implementation via the Metropolis-Hastings algorithm. Then, the desired probabilities were estimated based on the obtained sample. Main Results. The proposed method is tested on simulated data from the DREAM4 Challenges. Comparison with the leaders shows that the developed method quality surpasses the leader among the existing methods, the regularized gradient boosting machines method (RGBM), on some tests and is comparable on the othersin view of the results. At the same time, the proposed method is flexible enough and can be adapted to the other types of experimental data. Practical Relevance. The method is applicable in computational biology for research of the gene regulation mechanisms in various processes, including the tumor growth or the immune system operation.

Subject of Research. The paper considers a method for solution of the nondeterministic polynomial hard problem (NP-hard problem) of a minimal Boolean formula synthesis from a given truth table. The solution of this problem is proposed based on its reduction to the Boolean satisfiability problem (SAT). The issues of efficient and convenient software implementation are discussed for reducing nondeterministic polynomial hard problems to the satisfiability problem. Method. For a minimal Boolean formula synthesis, the constraint programming approach was used: a SATformula was created for a given truth table, satisfiable if and only if, there exists a Boolean formula of a given size that satisfies the given truth table. The developed method accent is the application of incremental satisfiability problem solvers. Main Results. A method is proposed for synthesis of a Boolean formula, minimal with respect to the number of operators and terminals, for a given truth table. The method is based on reducing to satisfiability problem and provides the usage of incremental satisfiability problem solvers. The kotlin-satlib framework is developed with the possibility to use the Kotlin and Java languages effectively and conveniently for the software implementation of reducing various nondeterministic polynomial-time hard problems to satisfiability problem. Native interaction with satisfiability problem solvers by Java Native Interface (JNI) technology is used. The proposed method for the minimal Boolean formula synthesis is implemented in the Kotlin programming language using the developed kotlin-satlib framework. Practical Relevance. An experimental study on the example of minimal Boolean formula synthesis has shown that the usage of incremental satisfiability problem solvers for nondeterministic polynomial hard problems is reasonable, since it reduces the total solving time in comparison with the non-incremental approach application.

Subject of Research. The paper presents a new method for distribution evaluation of the reflective characteristics over a given volume — control zone. This distribution makes it possible to identify inhomogeneities, detect and evaluate the reflective characteristics of small-size objects in a homogeneous environment. The problem is solved using a probing ultra-wideband continuous signal and a set of receiving sensors. Method. The method is based on the principles of the tomography approach in signal processing — multichannel tomography. The control zone is divided into resolution elements. The distribution of the reflective characteristics is searched in a discretized form as the reflective characteristics vector with each component equal to reflective characteristic of corresponding resolution element. Specific effective scattering surfaces are considered as reflective characteristics of resolution elements. According to the principles of the multichannel tomography, a vector-matrix mapping equation is obtained, in which the reflection vector is the original, and the mapping is the measurements of the receiving sensors combined into a vector. This equation is the starting point for the reflection vector evaluation. Three variants of estimation are considered: the pseudo-inversion method, the pseudo-inversion method with averaging, and a new method based on correlation processing. Main Results. The analysis is carried out on the capabilities of the proposed method by computer experiments for the distribution evaluation of reflective characteristics by resolution elements, into which the area of responsibility is divided. Experiments have shown the advantage of the correlation method: this method, in contrast to pseudo-inversion methods, makes it possible to identify reflective resolution elements both when their number increases in the control zone and in the presence of the probing signal distortions. Practical Relevance. The results of the work can find application, for example, in the field of subsurface probing to identify inhomogeneities in a homogeneous medium.

Subject of Research.The paper considers an optimal adaptive control problem of the initial dynamic (economic) system in the frame of profit taxation procedure for extended reproduction in the case of numerical coefficient uncertainty. Methods.The problem is solved by an optimization method of dynamic programming in a linear-quadratic variant and an adaptive method of adjustable parameters. Main Results. A novel algorithm for optimal adaptive control of an economic system is proposed. The so-called generalized cost functional is introduced as a measure of reproduction costs with the minimum value of the functional. The problem under study is solved in the proposed interpretation for the first time. The theoretical analysis is attended with numerical calculation data. Practical Relevance.The results of the work are applicable as the real maintenance economic schemes for industrial extended production facilities, taking into account the minimization of generalized costs in the profit taxation procedure.

Subject of Research. The paper presents a study of prediction method for various properties of reactions, such as the type of reaction, suitable groups of solvents, catalysts for the reaction. Molecular fingerprint differences between products and reagents were calculated using the RdKit chemical library as a representation of the reactions. Molecular fingerprints are widely used to predict various properties of molecules. Knowledge of the reaction conditions is essential for successful planning of retrosynthesis. Chemical informatics methods can effectively find the relationship between reaction reagents and the necessary conditions for the reaction. At this, the costs of time and resources spent on the determination of the necessary set of conditions for the reaction are reduced. Prediction of solvent groups can significantly improve the quality of models and the applicability of approaches. Method. LightGBM and a neural network with Deep Feature Selection were taken as machine learning models. The results were evaluated with the F1-metric. For the models training and evaluation, the data was broken down into chemically dissimilar parts. Bayesian optimization was used to optimize the searching of parameters. Main Results. Experiments were carried out to predict the reaction type, catalysts and solvent groups for the reaction. The obtained results show that the MLP type of reaction can be predicted equal to 0.99, a MLP catalyst equal to 0.7, and MLP group of solvents equal to 0.68 with F1-metric based on the difference in molecular fingerprints between reagents and products of machine learning models. Significant quantity of catalysts and solvents are considered in the paper. Practical Relevance. Automated planning of retrosynthesis is one of the topical areas of research. During planning, a sequence of necessary reactions is drawn up. The considered method can be used for recommendation system development that can suggest a possible group of catalysts and solvents to a chemical specialist, and, thus, reduce the cost of resources and time to determine the necessary reaction conditions.

The paper considers a daylight transport system model with light pipes, which provides the illumination of building production areas with natural daylight. The presence of natural light generates considerable physiological effect and affects the energy consumption in a building. The paper discusses correct application of a daylight pipe system based on the use of natural free energy sunlight sources. The advantage of a vertical light pipe application is that the daylight is delivered to the given space. The light pipe system is an effective method of daylight improvement in the existing buildings. The paper presents approaches to illumination modeling using light pipes for achievement of the desired lighting result. Practical examples of modeling for different types of light tubes are given.

Subject of Research.Studies of thermal and mechanical properties of polymer filaments and fibers are carried out. Refinements are made to the previously obtained constitutive equation that describes deformation-relaxation processes in polymer materials. The refinement gives the possibility to describe the thermoviscoelastic behavior of the studied materials in a wide range of temperatures and mechanical stresses, as well as to obtain and study the polymer filaments condition equation in case of a variable temperature. Method. The state of polymer filaments and fibers is researched on the basis of the barrier theory using the balance equation, and the constitutive equations are obtained for the cases of one and a number of energy barriers. A one-barrier equation of polymer material condition is obtained by the thermodynamics method of elastic rods with taking into account the current temperature and the coefficient of linear expansion. The general equation of a polymer material condition is given for the case of an arbitrary number of barriers. Main Results. The constitutive equation describing the thermoviscoelastic properties of polymer materials is modernized. The condition equation of polymer fibers and filaments is obtained. A relationship between the maximum shrinkage temperature and the coefficient of linear expansion has been established. The dynamic modulus of elasticity is determined as a function of temperature. Practical Relevance. The paper illustrates the isometric heating method application for determination of the real modulus of elasticity as a function of temperature.

Subject of Research.The paper presents a technique for prediction of the mechanical properties of polymer materials. An equation is proposed for the highly elastic part of deformation in a differential-mode for one-dimensional polymer structures.  The equation establishes that the preceding mechanical impact on deformation material properties is irrelevant. Method. A recursive method for solution of the proposed differential equation not integrable in quadratures was proposed. Tensile diagrams were experimentally obtained for fibers made of highly oriented polymers such as polyamide and polyethylene terephthalate in five loading conditions. The first load consisted in uniform loading of the fiber to rupture. In the other cases, the loading was carried out in three stages: with holding at control points, complete unloading and subsequent loading to rupture. Main Results. An equation for the highly elastic part of the deformation in a differential form is proposed and solved. Tensile diagrams are presented for one-dimensional polymer samples made of polyamide and polyethylene terephthalate up to the rupture values under various loading conditions. It is found that the preceding mechanical impacts do not affect significantly on the sample deformation properties. Samples made of polyamide and polyethylene terephthalate have practically no memory. Thus, the highly elastic part of the deformation relaxes into a stable state. Practical Relevance. The research shows that in an equilibrium state (regardless of the deformation method) each level of mechanical stress corresponds to a certain value of the equilibrium deformation; for a fixed deformation there is a fixed value of stress. The modeling results make it possible to predict the behavior of polymer materials under various operating conditions.

Subject of Research.The identification of active modules in biological graphs, for example, gene graphs, is one of the important approaches to the interpretation of experimental biological data. One of the approaches for its solution is the application of an algorithm of the joint clustering in network and correlation spaces. The algorithm finds groups of genes that are located simultaneously close in the gene graph and have a high pairwise correlation according to the matrix of gene expression values. The algorithm is iterative and one of its key parameters is the chosen initial approximation, which affects both the run time and the quality of the results. We consider the determination problem of an initial approximation for this algorithm. A procedure based on independent component analysis is proposed for the problem solution. Method. The method of independent component analysis is applied to a centered matrix of expression values at the first step of the proposed procedure for finding of an initial approximation. Then, the genes specific to the component with a given level of statistical significance are identified for each component. The gene groups obtained for all independent components are chosen as the initial approximation. Main Results. The procedure application based on the independent component analysis reduces the number of gene groups in the initial approximation without the loss of accuracy. This fact, in turn, speeds up the running time of the clustering algorithm by an order of magnitude with the quality maintenance of the results. Practical Relevance. Acceleration of the algorithm of the joint clustering in network and correlation spaces without quality loss of the results increases significantly its convenience and simplifies its application for the interpretation of transcriptome data in bioinformatics and computational biology.

Subject of Research.The paper proposes a clinical decision support system using multimodal data. Method. The system is based on neural network models. The author proposes the methods of transfer learning with domain adaptation techniques, training on multimodal data and taking into account the negative knowledge transfer for the quality improvement of preliminary analysis of medical data with application of neural network models. Algorithms of neural networks for preliminary analysis of the patient study provide the analysis of multimodal data with consideration of the combination peculiarities of modalities, training of neural networks with specific domain adaptation techniques, and taking into account the phenomenon of the knowledge negative transfer for the increase of the neural network robustness to the natural equipment noise. Main Results. The proposed system is implemented as a web-platform. The implemented system effectiveness was assessed by involving 30 experts: doctors, students, and patients. A comparative assessment of the problems solution in various scenarios was carried out with the proposed system and without it. Experiments have shown that the proposed system application reduces the execution time of the most critical stages of scenarios. Practical Relevance. The proposed system is located in the ITMO domain at the uniform resource locatoraddress: http://mcp.itmo.ru and is used in the practice of the Almazov National Medical Research Centre of the Ministry of Health of Russia, and the “City Children's Infectious Disease Clinical Hospital” Healthcare Institution in Minsk. The system is recommended for the application in clinical hospitals, individual practitioners and teaching radiologists.