Pub Date : 2023-06-02DOI: 10.32362/2500-316x-2023-11-3-86-103
I. Lebo
Objectives. The paper aimed to review and analyze the results of works devoted to numerical modeling of experiments on the interaction of high-power ultraviolet (UV) laser pulses with condensed targets. The experiments were carried out at GARPUN, the powerful KrF-laser facility at the P.N. Lebedev Physical Institute of the Russian Academy of Sciences (Moscow). The relevance of the research is related to the use of excimer UV lasers as a driver for a thermonuclear reactor. Physical aspects of laser-plasma interaction, including those related to the possibility of using two-sided cone target in a fission-fusion reactor, are discussed.Methods. The research is based on physico-mathematical models, including Euler and Lagrange.Results. The mathematical modeling of three types of natural experiments is presented: (1) burning through different thicknesses of Al foils by high-power UV laser; (2) studying hydrodynamic instability development at the UV laser acceleration of thin polymer films and features of turbulent zone formation; (3) interaction of high-power UV laser pulses with two-layer targets (Al + Plexiglas) and study of fine structures. Numerical modeling showed that a hybrid reactor with UV laser driver can use targets in the form of two-sided counter cones.Conclusions. Physico-mathematical models are developed along with 2D codes in Lagrangian and Eulerian coordinates as confirmed in the results of natural experiments. The models can be used to describe the physics of high-power UV laser pulses interacting with various targets and forecast the results of reactor-scale experiments.
{"title":"Mathematical modeling of experiments on the interaction of a high-power ultraviolet laser pulse with condensed targets","authors":"I. Lebo","doi":"10.32362/2500-316x-2023-11-3-86-103","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-3-86-103","url":null,"abstract":"Objectives. The paper aimed to review and analyze the results of works devoted to numerical modeling of experiments on the interaction of high-power ultraviolet (UV) laser pulses with condensed targets. The experiments were carried out at GARPUN, the powerful KrF-laser facility at the P.N. Lebedev Physical Institute of the Russian Academy of Sciences (Moscow). The relevance of the research is related to the use of excimer UV lasers as a driver for a thermonuclear reactor. Physical aspects of laser-plasma interaction, including those related to the possibility of using two-sided cone target in a fission-fusion reactor, are discussed.Methods. The research is based on physico-mathematical models, including Euler and Lagrange.Results. The mathematical modeling of three types of natural experiments is presented: (1) burning through different thicknesses of Al foils by high-power UV laser; (2) studying hydrodynamic instability development at the UV laser acceleration of thin polymer films and features of turbulent zone formation; (3) interaction of high-power UV laser pulses with two-layer targets (Al + Plexiglas) and study of fine structures. Numerical modeling showed that a hybrid reactor with UV laser driver can use targets in the form of two-sided counter cones.Conclusions. Physico-mathematical models are developed along with 2D codes in Lagrangian and Eulerian coordinates as confirmed in the results of natural experiments. The models can be used to describe the physics of high-power UV laser pulses interacting with various targets and forecast the results of reactor-scale experiments.","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134225993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-02DOI: 10.32362/2500-316x-2023-11-3-17-29
S. Kramarov, O. R. Popov, I. Dzhariev, E. A. Petrov
Objectives. In order to model and analyze the information conductivity of complex networks having an irregular structure, it is possible to use percolation theory methods known in solid-state physics to quantify how close the given network is to a percolation transition, and thus to form a prediction model. Thus, the object of the study comprises international information networks structured on the basis of dictionaries of model predictive terms thematically related to cutting-edge information technologies.Methods. An algorithmic approach is applied to establish the sequence of combining the necessary operations for automated processing of textual information by the internal algorithms of specialized databases, software environments and shells providing for their integration during data transmission. This approach comprises the stages of constructing a terminological model of the subject area in the Scopus bibliographic database, then processing texts in natural language with the output of a visual map of the scientific landscape of the subject area in the VOSviewer program, and then collecting the extended data of parameters characterizing the dynamics of the formation of links of the scientific terminological network in the Pajek software environment.Results. Visual cluster analysis of the range of 645-3364 terms in the 2004-2021 dynamics of the memory and data storage technologies category, which are integrated into a total of 23 clusters, revealed active cluster formation in the field of the term quantum memory. On this basis, allowing qualitative conclusions are drawn concerning the local dynamics of the scientific landscape. The exploratory data analysis carried out in the STATISTICA software package indicates the correlation of the behavior of the introduced MADSTA keyword integrator with basic terms including periods of extremes, confirming the correctness of the choice of the methodology for detailing the study by year.Conclusions. A basis is established for the formation of a set of basic parameters required for an extensive computational modeling of a cluster formation in the semantic field of the scientific texts, especially in relation to simulations of the formation of the largest component of the network and percolation transitions.
{"title":"Dynamics of link formation in networks structured on the basis of predictive terms","authors":"S. Kramarov, O. R. Popov, I. Dzhariev, E. A. Petrov","doi":"10.32362/2500-316x-2023-11-3-17-29","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-3-17-29","url":null,"abstract":"Objectives. In order to model and analyze the information conductivity of complex networks having an irregular structure, it is possible to use percolation theory methods known in solid-state physics to quantify how close the given network is to a percolation transition, and thus to form a prediction model. Thus, the object of the study comprises international information networks structured on the basis of dictionaries of model predictive terms thematically related to cutting-edge information technologies.Methods. An algorithmic approach is applied to establish the sequence of combining the necessary operations for automated processing of textual information by the internal algorithms of specialized databases, software environments and shells providing for their integration during data transmission. This approach comprises the stages of constructing a terminological model of the subject area in the Scopus bibliographic database, then processing texts in natural language with the output of a visual map of the scientific landscape of the subject area in the VOSviewer program, and then collecting the extended data of parameters characterizing the dynamics of the formation of links of the scientific terminological network in the Pajek software environment.Results. Visual cluster analysis of the range of 645-3364 terms in the 2004-2021 dynamics of the memory and data storage technologies category, which are integrated into a total of 23 clusters, revealed active cluster formation in the field of the term quantum memory. On this basis, allowing qualitative conclusions are drawn concerning the local dynamics of the scientific landscape. The exploratory data analysis carried out in the STATISTICA software package indicates the correlation of the behavior of the introduced MADSTA keyword integrator with basic terms including periods of extremes, confirming the correctness of the choice of the methodology for detailing the study by year.Conclusions. A basis is established for the formation of a set of basic parameters required for an extensive computational modeling of a cluster formation in the semantic field of the scientific texts, especially in relation to simulations of the formation of the largest component of the network and percolation transitions.","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125412258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-02DOI: 10.32362/2500-316x-2023-11-3-7-16
A. S. Albychev, S. Kudzh
Objectives. The development and implementation of information and computing architecture and information support for a state central bank digital currency (CBDC) is based on the selection of a software and hardware platform, including technologies and methods for supporting interaction between the elements of the computing complex. The implementation of CBDC technologies significantly depends both on the operational and computing architecture, as well as on the technological characteristics of the means for implementing digital currency information support, which determines the need to develop an appropriate research environment. Thus, the present study sets out to develop an infrastructure for the experimental research environment of the operational and computing architecture used to provide information support for the CBDC.Methods. Digital technologies required for forming an CBDC implementation stack are under development in many countries of the world. The basis for the formation of a software and hardware complex for providing CBDC information support is comprised of theoretical and experimental studies into contemporary digital transaction management tools.Results. The main architectural and technological components that make up the CBDC operational and computing environment comprise operational and computing architectures, blockchain technologies, consensus algorithms, and various forms of digital currencies. Five CBDC operational and computing architecture options are presented. Information models of interaction between the participants in transactions of the central bank digital currency were studied with the aim of establishing the effects of an architectural solution to the characteristics of the computing complex used to provide information support. Features of various digital currencies in the form of accounts and tokens were analyzed.Conclusions. A research environment infrastructure for the CBDC operational and computing information support architecture has been developed. The prerequisites for a comprehensive analysis of the technological characteristics of the CBDC operational and computing environment are set out along with a comparison of operational and computing architecture variants. As a result of the analysis, a summary list of the characteristics of the studied architectures is drawn up. This provides for selecting the optimal operational and computing architecture depending on the requirements imposed on the CBDC.
{"title":"Development of a research environment for the operational and computational architecture of central bank digital currency software","authors":"A. S. Albychev, S. Kudzh","doi":"10.32362/2500-316x-2023-11-3-7-16","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-3-7-16","url":null,"abstract":"Objectives. The development and implementation of information and computing architecture and information support for a state central bank digital currency (CBDC) is based on the selection of a software and hardware platform, including technologies and methods for supporting interaction between the elements of the computing complex. The implementation of CBDC technologies significantly depends both on the operational and computing architecture, as well as on the technological characteristics of the means for implementing digital currency information support, which determines the need to develop an appropriate research environment. Thus, the present study sets out to develop an infrastructure for the experimental research environment of the operational and computing architecture used to provide information support for the CBDC.Methods. Digital technologies required for forming an CBDC implementation stack are under development in many countries of the world. The basis for the formation of a software and hardware complex for providing CBDC information support is comprised of theoretical and experimental studies into contemporary digital transaction management tools.Results. The main architectural and technological components that make up the CBDC operational and computing environment comprise operational and computing architectures, blockchain technologies, consensus algorithms, and various forms of digital currencies. Five CBDC operational and computing architecture options are presented. Information models of interaction between the participants in transactions of the central bank digital currency were studied with the aim of establishing the effects of an architectural solution to the characteristics of the computing complex used to provide information support. Features of various digital currencies in the form of accounts and tokens were analyzed.Conclusions. A research environment infrastructure for the CBDC operational and computing information support architecture has been developed. The prerequisites for a comprehensive analysis of the technological characteristics of the CBDC operational and computing environment are set out along with a comparison of operational and computing architecture variants. As a result of the analysis, a summary list of the characteristics of the studied architectures is drawn up. This provides for selecting the optimal operational and computing architecture depending on the requirements imposed on the CBDC.","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122441398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-02DOI: 10.32362/2500-316x-2023-11-3-46-55
S. I. Sovetov, S. Tyurin
Objectives. The basic element of a field-programmable gate array is a lookup table (LUT). While in canonical normal form LUTs generally implement only one logical function for a given configuration, in this case, there is always an inactive pass transistor element. Moreover, using a single LUT for a single function reduces system-on-a-chip (SoC) scalability. Therefore, the purpose of the present work is to develop a LUT structure for implementing several logic functions simultaneously on inactive transmitting transistors.Methods. The evolution of LUT structure is presented for three variables, in which the number of simultaneously implemented functions increases. To implement additional functions, the logical device was decomposed with a different number of variables. The structures were modeled in the Multisim electrical simulation system.Results. The presented simulation of more than two logic functions on inactive parts of the LUT shows the simultaneous operation of two and four logic functions. The complexity for a different number of variables and number of implemented functions is compared.Conclusions. The simulation results demonstrate the operability of LUT structures in which several logical functions are performed. Thus, when implementing additional functions in the new structure, a smaller number of transmitting transistors is required as compared to a conventional LUT, thus increasing device functionality. The presented solution can be used to increase the number of simultaneously implemented functions of the same variables, which can be important e.g., when implementing code transformations.
{"title":"Method for synthesizing a logic element that implements several functions simultaneously","authors":"S. I. Sovetov, S. Tyurin","doi":"10.32362/2500-316x-2023-11-3-46-55","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-3-46-55","url":null,"abstract":"Objectives. The basic element of a field-programmable gate array is a lookup table (LUT). While in canonical normal form LUTs generally implement only one logical function for a given configuration, in this case, there is always an inactive pass transistor element. Moreover, using a single LUT for a single function reduces system-on-a-chip (SoC) scalability. Therefore, the purpose of the present work is to develop a LUT structure for implementing several logic functions simultaneously on inactive transmitting transistors.Methods. The evolution of LUT structure is presented for three variables, in which the number of simultaneously implemented functions increases. To implement additional functions, the logical device was decomposed with a different number of variables. The structures were modeled in the Multisim electrical simulation system.Results. The presented simulation of more than two logic functions on inactive parts of the LUT shows the simultaneous operation of two and four logic functions. The complexity for a different number of variables and number of implemented functions is compared.Conclusions. The simulation results demonstrate the operability of LUT structures in which several logical functions are performed. Thus, when implementing additional functions in the new structure, a smaller number of transmitting transistors is required as compared to a conventional LUT, thus increasing device functionality. The presented solution can be used to increase the number of simultaneously implemented functions of the same variables, which can be important e.g., when implementing code transformations.","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125179011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-02DOI: 10.32362/2500-316x-2023-11-3-56-69
A. Alexandrov, S. Borisov, L. Bunina, S. Bikovsky, I. V. Stepanova, A. P. Titov
Objectives. The wear monitoring of metal structural elements of power plants—in particular, pipelines of nuclear power plants—is an essential means of ensuring safety during their operation. Monitoring the state of the pipeline by direct inspection requires a considerable amount of labor, as well as, in some cases, the suspension of power plant operation. In order to reduce costs during monitoring measures, it is proposed to use mathematical modeling. This work aimes to develop a mathematical model of a diagnostic system for assessing the probability of detection of defects by solving inverse problems.Methods. A binomial model for assessing the reliability of monitoring, comprising the Berens-Hovey parametric model of the probability of detection of defects and a parametric model based on studying test samples, was analyzed. As an alternative to this binomial model, a computational method for assessing the reliability of non-destructive testing systems by solving an inverse problem was proposed. To determine the parameters of the defect detection probability curve, the model uses data obtained by various monitoring teams over a long period of power plant operation. To serve as initial data, the defect distribution density over one or more of the following characteristics can be used: depth, length, and/or cross-sectional area of the defect. Using the proposed mathematical model, a series of test calculations was performed based on nine combinations of initial data. The combinations differed in the confidence coefficient of the initial monitoring system, the parameters of the distribution of defects, and the sensitivity of the monitoring system.Results. The calculation data were used to construct curves of the probability density of detected defects as a function of the defect size, recover the values of the defect distribution parameters under various test conditions, and estimate the error of recovering the parameters. The degree of imperfection of the system was estimated using the curve of the detection probability of a defect by a certain monitoring system.Conclusions. Under constraints on the data sample size, the proposed methodology allows the metal monitoring results to be applied with greater confidence than currently used methods at the same time as evaluating the efficiency of monitoring carried out by individual test teams or laboratories. In future, this can be used to form the basis of a recommendation of the involvement of a particular team to perform diagnostic work.
{"title":"Statistical model for assessing the reliability of non-destructive testing systems by solving inverse problems","authors":"A. Alexandrov, S. Borisov, L. Bunina, S. Bikovsky, I. V. Stepanova, A. P. Titov","doi":"10.32362/2500-316x-2023-11-3-56-69","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-3-56-69","url":null,"abstract":"Objectives. The wear monitoring of metal structural elements of power plants—in particular, pipelines of nuclear power plants—is an essential means of ensuring safety during their operation. Monitoring the state of the pipeline by direct inspection requires a considerable amount of labor, as well as, in some cases, the suspension of power plant operation. In order to reduce costs during monitoring measures, it is proposed to use mathematical modeling. This work aimes to develop a mathematical model of a diagnostic system for assessing the probability of detection of defects by solving inverse problems.Methods. A binomial model for assessing the reliability of monitoring, comprising the Berens-Hovey parametric model of the probability of detection of defects and a parametric model based on studying test samples, was analyzed. As an alternative to this binomial model, a computational method for assessing the reliability of non-destructive testing systems by solving an inverse problem was proposed. To determine the parameters of the defect detection probability curve, the model uses data obtained by various monitoring teams over a long period of power plant operation. To serve as initial data, the defect distribution density over one or more of the following characteristics can be used: depth, length, and/or cross-sectional area of the defect. Using the proposed mathematical model, a series of test calculations was performed based on nine combinations of initial data. The combinations differed in the confidence coefficient of the initial monitoring system, the parameters of the distribution of defects, and the sensitivity of the monitoring system.Results. The calculation data were used to construct curves of the probability density of detected defects as a function of the defect size, recover the values of the defect distribution parameters under various test conditions, and estimate the error of recovering the parameters. The degree of imperfection of the system was estimated using the curve of the detection probability of a defect by a certain monitoring system.Conclusions. Under constraints on the data sample size, the proposed methodology allows the metal monitoring results to be applied with greater confidence than currently used methods at the same time as evaluating the efficiency of monitoring carried out by individual test teams or laboratories. In future, this can be used to form the basis of a recommendation of the involvement of a particular team to perform diagnostic work.","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127142882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-02DOI: 10.32362/2500-316x-2023-11-3-70-85
E. Kartashov
Objectives. Processes of energy transfer in solids and resultant thermal loads are widespread in nature and technology. This explains the scientific and practical significance of constructing a theory of these processes, as well as developing effective methods for studying the modeled concepts developed on this basis. The purpose of such studies is to determine basic flux patterns of complex processes occurring especially under conditions of powerful energy impacts in various technological operations. These include plasma-chemical processing of materials, their processing in infrared furnaces and solar plants, intense heating of materials carried out by laser or electron beams, and the use of powerful radiation emitters for thermal hardening and hardening of the surface of products. In these cases, the phenomenon of thermal shock arises, forming one of the central topics in thermomechanics and strength physics of solids. The present work considers an open theoretical problem of thermal shock in terms of a generalized model of dynamic thermoelasticity under conditions of a locally nonequilibrium heat transfer process. Depending on the type and curvature of the boundary surface of the considered massive body, the model can be used to study the problem in three coordinate systems: cartesian coordinates—a massive body bounded by a flat surface; spherical coordinates—a massive body with an internal spherical cavity; cylindrical coordinates—a massive body with an internal cylindrical cavity. Three types of intensive heating are considered: temperature heating, thermal heating, and heating by medium. Following the development of an analytical solution, the results of conducted numerical experiments are presented along with their physical analysis.Methods. The study applies methods and theorems of operational calculus according to the theory of special functions.Results. Generalized model representations of thermal shock are developed in terms of dynamic thermoelasticity for locally nonequilibrium heat transfer processes simultaneously in three coordinate systems: Cartesian, spherical, and cylindrical. The presence of curvature of the boundary surface of the thermal shock area substantiates the initial statement of the dynamic problem in displacements using the proposed corresponding “compatibility” equation.Conclusions. A generalized dynamic model of the thermal reaction of massive bodies with internal cavities simultaneously in Cartesian, spherical, and cylindrical coordinate systems under conditions of intense temperature heating, thermal heating, and heating by medium is proposed. The model is considered in terms of displacements based on local nonequilibrium heat transfer. A numerical experiment carried out according to the obtained analytical solution for stresses forms a basis for a description of the wave nature of the propagation of a thermoelastic wave. A comparison with the classical solution is made without taking into account local nonequili
{"title":"Developing generalized model representations of thermal shock for local non-equilibrium heat transfer processes","authors":"E. Kartashov","doi":"10.32362/2500-316x-2023-11-3-70-85","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-3-70-85","url":null,"abstract":"Objectives. Processes of energy transfer in solids and resultant thermal loads are widespread in nature and technology. This explains the scientific and practical significance of constructing a theory of these processes, as well as developing effective methods for studying the modeled concepts developed on this basis. The purpose of such studies is to determine basic flux patterns of complex processes occurring especially under conditions of powerful energy impacts in various technological operations. These include plasma-chemical processing of materials, their processing in infrared furnaces and solar plants, intense heating of materials carried out by laser or electron beams, and the use of powerful radiation emitters for thermal hardening and hardening of the surface of products. In these cases, the phenomenon of thermal shock arises, forming one of the central topics in thermomechanics and strength physics of solids. The present work considers an open theoretical problem of thermal shock in terms of a generalized model of dynamic thermoelasticity under conditions of a locally nonequilibrium heat transfer process. Depending on the type and curvature of the boundary surface of the considered massive body, the model can be used to study the problem in three coordinate systems: cartesian coordinates—a massive body bounded by a flat surface; spherical coordinates—a massive body with an internal spherical cavity; cylindrical coordinates—a massive body with an internal cylindrical cavity. Three types of intensive heating are considered: temperature heating, thermal heating, and heating by medium. Following the development of an analytical solution, the results of conducted numerical experiments are presented along with their physical analysis.Methods. The study applies methods and theorems of operational calculus according to the theory of special functions.Results. Generalized model representations of thermal shock are developed in terms of dynamic thermoelasticity for locally nonequilibrium heat transfer processes simultaneously in three coordinate systems: Cartesian, spherical, and cylindrical. The presence of curvature of the boundary surface of the thermal shock area substantiates the initial statement of the dynamic problem in displacements using the proposed corresponding “compatibility” equation.Conclusions. A generalized dynamic model of the thermal reaction of massive bodies with internal cavities simultaneously in Cartesian, spherical, and cylindrical coordinate systems under conditions of intense temperature heating, thermal heating, and heating by medium is proposed. The model is considered in terms of displacements based on local nonequilibrium heat transfer. A numerical experiment carried out according to the obtained analytical solution for stresses forms a basis for a description of the wave nature of the propagation of a thermoelastic wave. A comparison with the classical solution is made without taking into account local nonequili","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129573748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-09DOI: 10.32362/2500-316x-2023-11-2-84-91
Objectives. An analysis of the problem of evaluating alternatives based on the results of expert paired comparisons is presented. The importance and relevance of this task is due to its numerous applications in a variety of fields, whether in the technical and natural sciences or in the humanities, ranging from construction to politics. In such contexts, the problem frequently arises concerning how to calculate an objective ratings vector based on expert evaluations. In terms of a mathematical formulation, the problem of finding the vector of objective ratings can be reduced to approximating the matrices of paired comparisons by consistent matrices.Methods. Analytical analysis and higher algebra methods are used. For some special cases, the results of numerical calculations are given.Results. The theorem stating that there is always a unique and consistent matrix that optimally approximates a given inversely symmetric matrix in a log-Euclidean metric is proven. In addition, derived formulas for calculating such a consistent matrix are presented. For small dimensions, examples are considered that allow the results obtained according to the derived formula to be compared with results for other known methods of finding a consistent matrix, i.e., for calculating the eigenvector and minimizing the discrepancy in the log-Chebyshev metric. It is proven that all these methods lead to the same result in dimension 3, while in dimension 4 all results are already different.Conclusions. The results obtained in the paper allow us to calculate the vector of objective ratings based on expert evaluation data. This method can be used in strategic planning in cases where conclusions and recommendations are possible only on the basis of expert evaluations.
{"title":"Extremum in the problem of paired comparisons","authors":"","doi":"10.32362/2500-316x-2023-11-2-84-91","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-2-84-91","url":null,"abstract":"Objectives. An analysis of the problem of evaluating alternatives based on the results of expert paired comparisons is presented. The importance and relevance of this task is due to its numerous applications in a variety of fields, whether in the technical and natural sciences or in the humanities, ranging from construction to politics. In such contexts, the problem frequently arises concerning how to calculate an objective ratings vector based on expert evaluations. In terms of a mathematical formulation, the problem of finding the vector of objective ratings can be reduced to approximating the matrices of paired comparisons by consistent matrices.Methods. Analytical analysis and higher algebra methods are used. For some special cases, the results of numerical calculations are given.Results. The theorem stating that there is always a unique and consistent matrix that optimally approximates a given inversely symmetric matrix in a log-Euclidean metric is proven. In addition, derived formulas for calculating such a consistent matrix are presented. For small dimensions, examples are considered that allow the results obtained according to the derived formula to be compared with results for other known methods of finding a consistent matrix, i.e., for calculating the eigenvector and minimizing the discrepancy in the log-Chebyshev metric. It is proven that all these methods lead to the same result in dimension 3, while in dimension 4 all results are already different.Conclusions. The results obtained in the paper allow us to calculate the vector of objective ratings based on expert evaluation data. This method can be used in strategic planning in cases where conclusions and recommendations are possible only on the basis of expert evaluations.","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126306185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-09DOI: 10.32362/2500-316x-2023-11-2-92-99
I. Utyashev, A. F. Fatkhelislamov
Objectives. To study the direct and inverse problem of vibrations of a rectangular rod having a longitudinal notch, to analyze regularities of the behavior of natural frequencies and natural forms of longitudinal vibrations when changing the location and size of the notch, and to develop a method for uniquely identifying the parameters of the longitudinal notch using the natural frequencies of longitudinal vibrations of the rod.Methods. The rod with a longitudinal notch is modeled as two rods, where the first one does not have a notch, while the second one does. For connection, conjugation conditions are used, in which longitudinal vibrations and deformations are equated. The solution of the inverse problem is based on the construction of a frequency equation under the assumption that the desired parameters are included in the equation. Substituting natural frequencies into this equation, the nonlinear system with respect to unknown parameters is derived. The solution of the latter is the desired notch parameters.Results. Tables of eigenfrequencies and graphs of eigenforms are given for different notch parameters. The results for different boundary conditions are obtained and analyzed. A method for identifying notch parameters by a finite number of eigenfrequencies is presented. The inverse problem is shown to have two solutions, which are symmetrical about the center of the rod. The unambiguous solution requires eigenfrequencies of the same problem with different boundary conditions at the right end. By adding additional conditions at the ends of the rod, the inverse problem can be solved with new boundary conditions to construct the exact solution and develop an algorithm for checking the uniqueness of the solution.Conclusions. The developed method can be used to solve the problem of identification of geometric parameters of various parts and structures modeled by rods.
{"title":"Identification of a longitudinal notch of a rod by natural vibration frequencies","authors":"I. Utyashev, A. F. Fatkhelislamov","doi":"10.32362/2500-316x-2023-11-2-92-99","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-2-92-99","url":null,"abstract":"Objectives. To study the direct and inverse problem of vibrations of a rectangular rod having a longitudinal notch, to analyze regularities of the behavior of natural frequencies and natural forms of longitudinal vibrations when changing the location and size of the notch, and to develop a method for uniquely identifying the parameters of the longitudinal notch using the natural frequencies of longitudinal vibrations of the rod.Methods. The rod with a longitudinal notch is modeled as two rods, where the first one does not have a notch, while the second one does. For connection, conjugation conditions are used, in which longitudinal vibrations and deformations are equated. The solution of the inverse problem is based on the construction of a frequency equation under the assumption that the desired parameters are included in the equation. Substituting natural frequencies into this equation, the nonlinear system with respect to unknown parameters is derived. The solution of the latter is the desired notch parameters.Results. Tables of eigenfrequencies and graphs of eigenforms are given for different notch parameters. The results for different boundary conditions are obtained and analyzed. A method for identifying notch parameters by a finite number of eigenfrequencies is presented. The inverse problem is shown to have two solutions, which are symmetrical about the center of the rod. The unambiguous solution requires eigenfrequencies of the same problem with different boundary conditions at the right end. By adding additional conditions at the ends of the rod, the inverse problem can be solved with new boundary conditions to construct the exact solution and develop an algorithm for checking the uniqueness of the solution.Conclusions. The developed method can be used to solve the problem of identification of geometric parameters of various parts and structures modeled by rods.","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127444477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-09DOI: 10.32362/2500-316x-2023-11-2-72-83
D. A. Karpov, V. I. Struchenkov
Objectives. Methods for spline approximation of a sequence of points in a plane are increasingly used in various disciplines. A spline is defined as a single-valued function consisting of a known number of repeating elements, of which the most widely used are polynomials. When designing the routes of linear structures, it is necessary to consider a problem with an unknown number of elements. An algorithm implemented for solving this problem when designing a longitudinal profile was published earlier. Here, since the spline elements comprise circular arcs conjugated by line segments, the spline is a single-valued function. However, when designing a route plan, the spline is generally a multivalued function. Therefore, the previously developed algorithm is unsuitable for solving this problem, even if the same spline elements are used. The aim of this work is to generalize the obtained results to the case of approximation of multivalued functions while considering various features involved in designing the routes of linear structures. The first stage of this work consisted in determining the number of elements of the approximating spline using dynamic programming. In the present paper, the next stage of solving this problem is carried out.Methods. The spline parameters were optimized using a new mathematical model in the form of a modified Lagrange function and a special nonlinear programming algorithm. In this case, it is possible to analytically calculate the derivatives of the objective function with respect to the spline parameters in the absence of its analytical expression. Results. A mathematical model and algorithm were developed to optimize the parameters of a spline as a multivalued function consisting of circular arcs conjugated by line segments. The initial approximation is the spline obtained at the first stage.Conclusions. The previously proposed two-stage spline approximation scheme for an unknown number of spline elements is also suitable for approximating multivalued functions given by a sequence of points in a plane, in particular, for designing a plan of routes for linear structures.
{"title":"Optimization of spline parameters in approximation of multivalued functions","authors":"D. A. Karpov, V. I. Struchenkov","doi":"10.32362/2500-316x-2023-11-2-72-83","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-2-72-83","url":null,"abstract":"Objectives. Methods for spline approximation of a sequence of points in a plane are increasingly used in various disciplines. A spline is defined as a single-valued function consisting of a known number of repeating elements, of which the most widely used are polynomials. When designing the routes of linear structures, it is necessary to consider a problem with an unknown number of elements. An algorithm implemented for solving this problem when designing a longitudinal profile was published earlier. Here, since the spline elements comprise circular arcs conjugated by line segments, the spline is a single-valued function. However, when designing a route plan, the spline is generally a multivalued function. Therefore, the previously developed algorithm is unsuitable for solving this problem, even if the same spline elements are used. The aim of this work is to generalize the obtained results to the case of approximation of multivalued functions while considering various features involved in designing the routes of linear structures. The first stage of this work consisted in determining the number of elements of the approximating spline using dynamic programming. In the present paper, the next stage of solving this problem is carried out.Methods. The spline parameters were optimized using a new mathematical model in the form of a modified Lagrange function and a special nonlinear programming algorithm. In this case, it is possible to analytically calculate the derivatives of the objective function with respect to the spline parameters in the absence of its analytical expression. Results. A mathematical model and algorithm were developed to optimize the parameters of a spline as a multivalued function consisting of circular arcs conjugated by line segments. The initial approximation is the spline obtained at the first stage.Conclusions. The previously proposed two-stage spline approximation scheme for an unknown number of spline elements is also suitable for approximating multivalued functions given by a sequence of points in a plane, in particular, for designing a plan of routes for linear structures.","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117273207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-09DOI: 10.32362/2500-316x-2023-11-2-58-71
M. O. Bykova, V. Balandin
Objectives. The aim of the present work is to determine the fractal dimension parameter calculated for a sequence of R–R intervals in order to identify the boundaries of its change for healthy and sick patients, as well as the possibility of its use as an additional factor in the detection of cardiac pathology.Methods. In order to determine the fractal dimension parameter, the Hurst-, Barrow-, minimum coverage area-, and Higuchi methods are used. For assessing the stationarity of a number of electrocardiography (ECG) intervals, a standard method is used to compare arithmetic averages and variances from samples of the total data array of ECG intervals. To identify differences in fractal dimensions of healthy and sick patients, this parameter was ranked. Using the Kolmogorov–Smirnov two-sample criterion, the difference between the distribution laws in the samples for healthy and sick patients is shown.Results. Among the considered methods for calculating the fractal dimension, the Higuchi method demonstrates the smallest data spread between healthy patients. By ranking the calculated fractional dimension values, it was possible to identify the difference between this parameter for healthy and sick patients. The difference in the distribution of fractal dimension of healthy and sick patients is shown to be statistically significant for the coverage and Higuchi methods. At the same time, when using the traditional Hurst method, there is no reason to reject the null hypothesis that two groups of patients belong to the same general population.Conclusions. Based on the obtained data, the difference between the fractal dimension indicators of the duration of R–R intervals of healthy and sick patients is shown to be statistically significant when using the Higuchi method. The fractal dimensions of healthy and sick patients can be effectively distinguished by ranking samples. The results of the research substantiate prospects for further studies aimed at using fractal characteristics of the heart rhythm to identify abnormalities of the latter, which can serve as an additional factor in determining heart pathologies.
{"title":"Methodological features of the analysis of the fractal dimension of the heart rate","authors":"M. O. Bykova, V. Balandin","doi":"10.32362/2500-316x-2023-11-2-58-71","DOIUrl":"https://doi.org/10.32362/2500-316x-2023-11-2-58-71","url":null,"abstract":"Objectives. The aim of the present work is to determine the fractal dimension parameter calculated for a sequence of R–R intervals in order to identify the boundaries of its change for healthy and sick patients, as well as the possibility of its use as an additional factor in the detection of cardiac pathology.Methods. In order to determine the fractal dimension parameter, the Hurst-, Barrow-, minimum coverage area-, and Higuchi methods are used. For assessing the stationarity of a number of electrocardiography (ECG) intervals, a standard method is used to compare arithmetic averages and variances from samples of the total data array of ECG intervals. To identify differences in fractal dimensions of healthy and sick patients, this parameter was ranked. Using the Kolmogorov–Smirnov two-sample criterion, the difference between the distribution laws in the samples for healthy and sick patients is shown.Results. Among the considered methods for calculating the fractal dimension, the Higuchi method demonstrates the smallest data spread between healthy patients. By ranking the calculated fractional dimension values, it was possible to identify the difference between this parameter for healthy and sick patients. The difference in the distribution of fractal dimension of healthy and sick patients is shown to be statistically significant for the coverage and Higuchi methods. At the same time, when using the traditional Hurst method, there is no reason to reject the null hypothesis that two groups of patients belong to the same general population.Conclusions. Based on the obtained data, the difference between the fractal dimension indicators of the duration of R–R intervals of healthy and sick patients is shown to be statistically significant when using the Higuchi method. The fractal dimensions of healthy and sick patients can be effectively distinguished by ranking samples. The results of the research substantiate prospects for further studies aimed at using fractal characteristics of the heart rhythm to identify abnormalities of the latter, which can serve as an additional factor in determining heart pathologies.","PeriodicalId":282368,"journal":{"name":"Russian Technological Journal","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115696627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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