bluuebunny/crossref_metadata_2025_split huggingface dataset:
About grid generation in constructions bounded by the surfaces of revolution
Authors: Artyomova Natalya A , Ushakova Olga V 
Published: December 2021

Abstract
For constructions bounded by the surfaces of revolution, structured grid generation technique is presented. Its technology has been elaborated within the variational approach for constructing optimal grids satisfying optimality criteria: closeness of grids to uniform ones, closeness of grids to orthogonal ones and adaptation to a given function. Grid generation has been designed for numerical solution of the differential equations modeling the vortex processes of multi-component hydrodynamics. In the technology, the three-dimensional construction in which it is required to construct a grid is represented in the form of the curvilinear hexahedron defining its configuration. The specific feature of the required configurations is that some faces of a curvilinear hexahedron lie in one plane and along edges of adjoining faces grid cells degenerate into prisms. Grid generation in the considered constructions has started to be developed by the elaboration of algorithms for the volume of revolution which has become the basic construction. The basic construction is obtained by the rotation through 180? around the axis of a generatrix consisting of straight line segments, arcs of circles and ellipses. Then the deformed volumes of revolutions are considered along with the generalizations of the volume of revolution which represent constructions obtained by the surfaces of revolution with parallel axis of rotation. The aim of the further development of the technology is to consider more and more complicated constructions and elaborate the technology for them. In the presentation, the current state of the development of the technology is given. Examples of generated grids are supplied.
Data-driven turbulence modelling using symbolic regression
Authors: Chakrabarty A , Yakovenko S N 
Published: December 2021

Abstract
The study is focused on the performance of machine-learning methods applied to improve the velocity field predictions in canonical turbulent flows by the Reynolds-averaged Navier–Stokes (RANS) equation models. A key issue here is to approximate the unknown term of the Reynolds stress (RS) tensor needed to close the RANS equations. A turbulent channel flow with the curved backward-facing step on the bottom has the high-fidelity LES data set. It is chosen as the test case to examine possibilities of GEP (gene expression programming) of formulating the enhanced RANS approximations. Such a symbolic regression technique allows us to get the new explicit expressions for the RS anisotropy tensor. Results obtained by the new model produced using GEP are compared with those from the LES data (serving as the target benchmark solution during the machine-learning algorithm training) and from the conventional RANS model with the linear gradient Boussinesq hypothesis for the Reynolds stress tensor.
Weakly supervised semantic segmentation of tomographic images in the diagnosis of stroke
Authors: Dobshik A V , Tulupov A A , Berikov V B 
Published: December 2021

Abstract
This paper presents an automatic algorithm for the segmentation of areas affected by an acute stroke in the non-contrast computed tomography brain images. The proposed algorithm is designed for learning in a weakly supervised scenario when some images are labeled accurately, and some images are labeled inaccurately. Wrong labels appear as a result of inaccuracy made by a radiologist in the process of manual annotation of computed tomography images. We propose methods for solving the segmentation problem in the case of inaccurately labeled training data. We use the U-Net neural network architecture with several modifications. Experiments on real computed tomography scans show that the proposed methods increase the segmentation accuracy.
The automated construction of a scheme for solving compute-intensive problems based on the ontological approach and Semantic Web technologies
Authors: Glinskiy B M , Sapetina A F , Snytnikov A V , Zagorulko Y A , Zagorulko G B 
Published: December 2021

Abstract
This paper describes the tools for supporting researchers in the development of a parallel code. The tools are based on the ontology of the knowledge area “Support for solving compute-intensive problems of mathematical physics on supercomputers”. The main result of these tools operation is a scheme for solving the problem, built according to its specification provided by the user. The scheme includes the most suitable mathematical models for solving the problem, numerical methods, algorithms, and parallel architectures, links to available fragments of a parallel code that the user can use when developing his own code. The scheme construction is carried out on the basis of ontology and expert rules built using the Semantic Web technology.
Extended methodology for deriving formal concepts
Authors: Semenova V A , Smirnov S V 
Published: December 2021

AbstractTwo methodologies for formal concepts derivation are considered: the classical one, which focuses on the posterior analysis of the object’s properties of the studied knowledge domain, and non-classical, the cornerstone of which is the a priori formation of the set of measured object’s properties and the determination of existential relations on this set. In the article, firstly, a position is fixed in the technological chain of the target transformation of the source data, where the difference between considered methodologies shows itself. Secondly, the commonality of these two approaches is established in the aspect of the unity of their hypothetical-deductive basis. In this case, the cognitive activity of the subject is expressed first in a priori and then in a posteriori conceptual scaling of the measured properties. The work demonstrates the need for the joint use of the considered methodologies at processing incomplete and inconsistent empirical data about studied knowledge domain. The intermediate consolidation of these methodologies is possible only on the basis of multi-valued logic.
Approach to automatic population of ontologies of scientific subject domain using lexico-syntactic patterns
Authors: Zagorulko Yu A , Sidorova E A , Akhmadeeva I R , Sery A S 
Published: December 2021

Abstract
This paper presents an approach to automatic population of ontologies of a scientific subject domain (SSD) using Lexico-Syntactic Patterns (LSPs) and a corpus of texts related to modeled domain. The main feature of this approach is that such patterns are automatically built based on Ontology Design Patterns of other types provided by the system for the automated development of SSD ontologies using heterogeneous Ontology Design Patterns. The implementation of the ontology population using constructed LSPs is described in detail. The results of the experiments on the SSD ontology population are presented. It is noted that there is a problem in establishing a subject of a relation when extracting facts. To address this problem, the authors are planning to employ the coreference resolution methods.
New possibilities of the PCA-Seq method in the analysis of time series (on the example of solar activity)
Authors: Efimov V M , Efimov K V , Polunin D A , Kovaleva V Y 
Published: December 2021

Abstract
When analyzing a 1D time series, it is traditional to represent it as the sum of the trend, cyclical components and noise. The trend is seen as an external influence. However, the impact can be not only additive, but also multiplicative. In this case, not only the level changes, but also the amplitude of the cyclic components. In the PCA-Seq method, a generalization of SSA, it is possible to pre-standardize fragments of a time series to solve this problem. The algorithm is applied to the Anderson series – a sign alternating version of the well-known Wolf series, reflecting the 22-year Hale cycle. The existence of this cycle is not disputed at high solar activity, but there are doubts about the constancy of its period at this time, as well as its existence during the epoch of low solar activity. The processing of the series by the PCA-Seq method revealed clear oscillations fluctuations of almost constant amplitude with an average period of 21.9 years, and it was found that the correlation of these oscillations with the time axis for 300 years does not differ significantly from zero. This confirms the hypothesis of the existence of 22-year oscillations in solar activity even at its minima, like the Maunder minimum.
A structure of the solenoidal 2D vector and 2-tensor fields given in a domain with the conformal Riemannian metric
Authors: Yu Derevtsov E 
Published: December 2021

Abstract
The Helmholtz decomposition of a vector field on potential and solenoidal parts is much more natural from physical and geometric points of view then representations through the components of the vector in the Cartesian coordinate system of Euclidean space. The structure, representation through potentials and detailed decomposition for 2D symmetric m-tensor fields in a case of the Euclidean metric is known. For the Riemannian metrics similar results are known for vector fields. We investigate the properties of the solenoidal vector and 2-tensor two-dimensional fields given in the Riemannian domain with the conformal metric and establish the connections between the fields and metrics.
On the modeling of ultrasound wave propagation in the frame of inverse problem solution
Authors: Novikov N S , Klyuchinskiy D V , Shishlenin M A , Kabanikhin S I 
Published: December 2021

Abstract
In this paper we consider the inverse problem of detecting the inclusions inside the human tissue by using the acoustic sounding wave. The problem is considered in the form of coefficient inverse problem for first-order system of PDE and we use the gradient descent approach to recover the coefficients of that system. The important part of the sceme is the solution of the direct and adjoint problem on each iteration of the descent. We consider two finite-volume methods of solving the direct problem and study their Influence on the performance of recovering the coefficients.
On the recovering of acoustic attenuation in 2D acoustic tomography
Authors: Shishlenin M A , Novikov N S , Klyuchinskiy D V 
Published: December 2021

AbstractThe inverse problem of recovering the acoustic attenuation in the inclusions inside the human tissue is considered. The coefficient inverse problem is formulated for the first-order system of PDE. We reduce the inverse problem to the optimization of the cost functional by gradient method. The gradient of the functional is determined by solving a direct and conjugate problem. Numerical results are presented.
Supercomputer model of dynamical dusty gas with intense momentum transfer between phases based on OpenFPM library
Authors: Grigoryev Vitaliy , Stoyanovskaya Olga , Snytnikov Nikolay 
Published: December 2021

Abstract
The paper considers the solution of model gas-dynamic problems (propagation of plane sound wave, one-dimensional shock tube problem, three-dimensional problem of a point explosion in a continuous medium) in the case of a gas-dust medium. The interaction of dust and gas was taken into account using the IDIC method within the SPH method used to solve gas-dynamic equations. An important feature of the work is the use of the open computational package OpenFPM, which makes it easy to carry out parallel computations. The main advantage of this package is the ready-made (implemented by the authors of the package) and intuitive, automatically parallelizable vector data structures, the use of which is identical both in the case of calculations on a personal computer and in the case of using supercomputer resources. The paper analyzes the efficiency of parallelization of numerical solutions of the considered problems.
Signals of electromagnetic tool with toroidal coils in highly deviated wells
Authors: Mikhaylov I , Surodina I , Glinskikh V , Nikitenko M 
Published: December 2021

Abstract
The research is aimed at expanding the applicability of the logging tool with toroidal coils from vertical to highly deviated wells. Its electromagnetic signals are computed with a three-dimensional finite-difference simulation algorithm on the computing resources of the Siberian Supercomputer Center of SB RAS, which is accompanied by a multi-aspect numerical analysis of the signals. We consider a wide range of geoelectric models with various resistivity contrasts: those of oil-, gas- and water-saturated reservoirs having a different number of horizontal boundaries and varying thicknesses, including the case of fine layering.
Monte Carlo method for solving the problem of predicting the computer network resistance against DoS attacks
Authors: Voevodin V A , Burenok D S , Cherniaev V S 
Published: December 2021

Abstract
The application of the Monte Carlo method to solving the problem of identifying and assessing the protection against DDoS attacks of weak nodes is considered. The field of research is of practical and theoretical interest, since the methods developed by the classical theory of reliability are focused on simple, stationary flows. Under the conditions of DDoS attacks, the flow of attacking requests is not stationary, so the known analytical models give an unacceptable error. For the reliability of the results, the freedom to choose the distribution function, the moments of arrival of the attacking requests, their duration and the response of the attacked node is required. The method is applicable for modelling a computer network when organizing an information security audit.
Monte Carlo method for predicting the stability of the functioning of the informatization object in the conditions of massive computer attacks
Authors: Voevodin V A 
Published: December 2021

Abstract
The application of the Monte Carlo method for solving the problem of predicting the functioning stability of the object of informatization in the conditions of massive computer attacks (MCA) is considered. The field of research represents practical and theoretical interests, since the methods developed by the theory of reliability are focused on simple, stationary, failure flows, which cannot be applied to the MCA conditions. In the conditions of the MCA, the period of normal functioning is commensurate with the recovery time, therefore, the application of the Poisson flow model leads to a significant error. To ensure the reliability of modeling, it is necessary to use an alternating process model, where the recovery time is commensurate with the period of operation and has a finite value, while analytical models of the real functioning processes are cumbersome, difficult to interpret and have no practical application.
Spatial-temporal variation of CO2emissions from private vehicle use in Japan
Authors: Long Yin , Yoshida Yoshikuni , Li Yuan , Gasparatos Alexandros 
Published: December 2021

AbstractThe transport sector is a major contributor to anthropogenic climate change through the emissions of large amounts of greenhouse gases from fossil fuel combustion. Private vehicles account for almost half of the transport energy demand, and are thus a major target for climate change mitigation efforts. However, emissions from private vehicles can have large variability due to various geographic, demographic and socioeconomic factors. This study aims to understand how such factors affect private vehicle emissions in Japan using a nationally representative survey of household energy consumption (n= 7370) for 2017. The results indicate a large temporal and spatial variability in private vehicle emissions. Annual emissions show three peaks associated with major holiday seasons in winter and summer. Some of the more noteworthy spatial patterns are the higher emissions in prefectures characterized by low population density and mountainous terrain. Income, city size and the fuel-saving driving behavior all have a significant effect on emissions. The results indicate the need for sub-regional and socioeconomically-sensitive mitigation efforts that reflect the very different emission patterns, and the factors affecting them. The strong effect of city size, which is often much more clear-cut than between prefectures, suggests that it is more appropriate to approach transport decarbonization in Japan at the city level.
Lectures on the superconformal index
Authors: Gadde Abhijit 
Published: December 2021

Abstract
In these lectures, we give a pedagogical introduction to the superconformal index. This is the writeup of the lectures given at the Winter School ‘YRISW 2020’ and is to appear in a special issue of J. Phys. A. The lectures are at a basic level and are geared towards a beginning graduate student interested in working with the superconformal index.
Basic properties of the mangrove tree branches as a raw material of wood pellets and briquettes
Authors: Nuryawan A , Syahputra R S , Azhar I , Risnasari I 
Published: December 2021

AbstractIn order to sustain mangrove forests, only branches part of the mangrove trees have been utilized. In this context, these parts have been used as the raw material of wood pellets and briquettes. These solid biofuels are produced by compressing pulverized woody biomass with or without additives in cubic-form or cylindrical units. In this study, five predominant mangrove trees, namelyAvicennia marina, Bruguiera sexangula, Excoecaria agallocha, Rhizopora apiculata,andR. mucronata, have been harvested their branches. Wood with and without bark derived from branches has been investigated for their fundamental properties, namely percentage of bark, ash-content, and physical properties (moisture content, density, and specific gravity). These properties will determine the quality class of the resulted wood pellets and briquettes considering pre-treatment or the nature of the branches’ wood.
Washing and Chopping Pre-treatment Effect of Vetiver Roots on Vetiver Oil Yield and Distillation Time
Authors: Sabila G M , Sephia C , Karliati T , Suhaya Y , Dungani R 
Published: December 2021

Abstract
Vetiver is a type of grass mainly used for its roots to be extracted into vetiver oil. Despite the increasing market demand, the productivity of vetiver oil in Indonesia still consider low. One of the determinant factors of the extraction yield is the pre-treatment before distillation. This study aimed to determine the best pre-treatment method to improve the vetiver oil extraction using water and steam distillation by looking at the yield, distillation rate, and forecasted distillation duration. The distillation process was using water and steam distillation method for 9 hours. The data analysis method used Durbin-Watson autocorrelation analysis. The feasibility test of polynomial regression was modelled with the F test and ANOVA variance test. The result showed that the combination of washing 2-3 times and chopping pre-treatments of vetiver roots with a size of ± 5 cm could significantly increase the extracted vetiver oil by producing the highest yield (0.36% (wet-based) and 0.47% (dry based)), the highest extraction rate (0.057%/h) and the fastest forecasted duration of the distillation (10.5 hours). The combination of washing and chopping pre-treatments of vetiver roots was the best method and could be an economical solution for low productivity problems of vetiver oil in Indonesia.
Community knowledge and involvement in mangrove ecosystem management in the coastal of Muara Gembong Bekasi
Authors: Salampessy M L , Febryano I G , Ichsan A C 
Published: December 2021

Abstract
Mangrove ecosystems have experienced pressure and decreased function due to abrasion and high land conversion activities for pond expansion. The government has tried to increase the role of the community for mangrove conservation but this effort has not obtained optimal results. This study aims to determine the understanding of coastal communities about Mangroves and community involvement in Mangrove ecosystem management. Methods of data collection using a questionnaire instrument, field observations, and in-depth interviews. Data analysis was done descriptively tabulated. The selection of respondents using purposive sampling. The results of the study stated that 60% of the community understood the importance of mangroves for their lives. The community understands that mangroves are a source of livelihood for the community and protect the coast from waves and abrasion. The community is actively involved in Mangrove planting program activities (53%) but based on activities initiated by the government in certain groups. Knowledge and community involvement in mangrove forest management are closely related to important community decisions to participate actively in mangrove forest management. Therefore, efforts to increase knowledge need to be increased through outreach activities and development of community empowerment programs.
Geodynamic risks of developing rockburst-hazardous deposits in the Far Eastern region
Authors: Fedotova Yu V , Anikin P A , Potapchuk M I 
Published: December 2021

Abstract
Geodynamic activity of the Earth’s crust depends on the parameters of the movement of lithospheric plates and stress fields, both inherited in aseismic areas and modified in seismic active ones. Geomechanical processes occur in rock mass under the influence of various natural (endogenous and exogenous) and man-made (anthropogenic) factors. The degree of influence of these factors on the change in the energy saturation of blocks of various ranks will depend on various factors. In the geological environment of natural and man-made systems, there are dynamic phenomena of various energy levels from acoustic noise (microseismic) to rockburst and mining-induced earthquakes, that is, there is always a geodynamic risk in the geological environment of natural and man-made systems, especially in mining ones. The conditions of the geodynamic risks occurrence at specific deposits are considered on the example of rockburst hazardous deposits in the Far Eastern region of the Russian Federation. The influence of natural seismic activity on the realization of mining-induced seismicity is shown.
Results of reinterpretation of marine geochemical survey on the Sakhalin shelf
Authors: Kostrov Yu V , Kamenev P A 
Published: December 2021

Abstract
Geochemical survey of hydrocarbons (HC) all over the world is a reliable tool of the complex of geological exploration, which allows to localize hydrocarbon saturation in structures exposed by seismic exploration, as well as to identify non-structural deposits. In 2011, a marine geochemical survey of the sorbed gases of bottom sediments was carried out on the shelf section of the northwest of Sakhalin Island. Based on the results of geochemical studies, 12 maps of the distribution of hydrocarbon and non-hydrocarbon gases in the work area and 7 maps of the distribution of metals in bottom sediments were constructed. Promising areas were distinguished by anomalies with the maximum content of parameters. The research area is characterized by a complex structure, located within the Baikal synclinal zone of the North Sakhalin oil and gas basin, which is part of the rift system of the Cenozoic sedimentary basins the Sea of Okhotsk. In 2019, the authors began to re-process and reinterpret the data in order to clarify the results. The work was based on modern theoretical foundations and methodological approaches of oil and gas prospecting geochemistry. The interpretation of the results was carried out on the basis of the model of interpretation of geochemical anomalies developed by the authors. Maps of anomalies were constructed according to 11 geochemical criteria and two geological and geochemical sections. The complex interpretation of geological and geochemical data was carried out taking into account the results of seismic exploration and drilling in a single project. According to the results of the complex interpretation, 6 promising sites were identified, which are ranked according to the degree of prospects.