bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geometric method for researching the robot service area under the obstacles for the limitations on links movement
Authors: Pritykin F N , Nefedov D I 
Published: May 2020

Abstract
The work is devoted to solving one of the problems of robot motion virtual simulation using computer graphics. The paper offers a method for studying the shape and position of the work envelop of manipulator mechanisms in the presence of restricted work envelopes in the workspace. The method for determining the work envelope is based on the construction of allowed configuration of robot mechanisms. A parameter describing the structure and maneuverability index in different parts of the work envelope is proposed. The construction of cross sections of service areas for different positions of restricted work envelopes allows determining the areas where the output link centers of various mechanisms can not be located. The conducted research makes it possible to place the trajectories of the output link in solving motion problems, which reduce the probability of deadlocks in the automated motion synthesis along the velocity vector.
The Axle Box Generator Efficiency Determination Using A Scalar Frequency Controlled Induction Electric Drive
Authors: Lysenko O A , Songin M V , Simakov A V 
Published: May 2020

Abstract
The article discusses a method for determining the axle box generator efficiency. The generator is installed in the axle box of the freight car. It is driven by a wheels pair. The axle box generator provides power supply to freight car systems: diagnostics, geolocation and telemetry. To determine the efficiency, an indirect method of determining the mechanical power transmitted to the axle box generator is considered. The electromagnetic torque is determined through the induction electric drive model parameters of the generator. The article describes an experimental unit. It consists of a test generator, an induction electric drive, and an open platform frequency converter. The converter control system was created in MexBios Development Studio software. Oscillograms of generator tests are presented.
Thermal energy recovery efficiency improvement of gas turbine technology
Authors: Paramonov A M , Rezanov E M 
Published: May 2020

Abstract
The research relevance on improving the thermal energy recovery efficiency of gas turbine technology is caused by the need to reduce the fuel and energy consumption when generating the electric energy. The research objective is to define the technically and economically feasible heat recovery ratio of exhaust gases after gas turbine in the heat regenerator. The optimization problem of the heat potential recovery process was solved. The algorithm to calculate the optimal temperature of heating the air supplied to the combustion chamber of the gas turbine unit was developed. Methods of mathematical modelling of heat exchange processes, methods of choosing the rational option in solving the optimization problem, and mathematical methods of solving the optimization problems were used in the paper. The influence analysis of the optimal air temperature required for burning the fuel in the combustion chamber on the technical and economic efficiency of the Siemens SGT-100 gas turbine equipment was carried out. The expediency of applying the performed studies results of practical application in designing and operating gas turbine machines was substantiated.
General Approach to Calculation of Magnetic System of Slow-Moving Linear Magneto-Electric Drive as Part of Electrical Complex
Authors: Tatevosyan A A , Bubnov A V , Andreeva E G , Tatevosyan A S 
Published: May 2020

Abstract
Article discusses approach to development of linear magneto-electric drive using slow-moving electromechanical converter with permanent magnets Design of electrical complex uses solution of problem of optimization of linear magneto-electric motor design according to criterion of maximum developed traction force. The law of force change is implemented sinusoidal with constant component, frequency of oscillations up to 10 Hz. The weight and size and electromagnetic parameters of the linear magneto-electric drive are refined using the finite element method. The article presents the results of calculation of the main geometric parameters of the magnetic system.
Technique and device for filter elements regeneration based on powder filter material
Authors: Ilyushchanka A , Charniak I , Kusin A , Kusin R , Zakreuski I , Eremin E N 
Published: May 2020

Abstract
The design of a device for filter elements regeneration is presented without disassembling the filters in which they are installed. A distinctive feature of the device is the use of a preliminarily vacuumed chamber designed to discharge contaminants from the surface of the filter element. This makes it possible to increase the operation time of the filters before they are disassembled in order to clean the filters on special stands or replace them. The efficiency of the device in production conditions is shown by the example of cleaning an aqueous solution of peat hydrohumate by powder filter elements.
The matching of images based on de Rham current formation
Authors: Chukanov S N 
Published: May 2020

Abstract
The application of the de Rham current theory for matching forms of images is considered. The determination the measure of differences between simplicial complexes of forms does not imply a point bijective correspondence between the structures of objects. The RKHS method for obtaining object shape metrics is proposed. The study of the forms of objects is proposed to be carried out by forming test vector fields. Simplicial complexes of objects can be supplemented by the functions of the elements representing the signals. To improve the accuracy of matching the forms of the source and terminal images, the original image is subjected to preliminary affine transformation. The minimization of the functional of the squared distance between the image forms is carried out on the basis of the QPSO algorithm.
Mathematical modeling and numerical algorithm for the gas displacement by water in an inhomogeneous porous medium
Authors: Kholmatova I I 
Published: May 2020

Abstract
The problems associated with the development of gas fields bounded by aquifer systems are considered in the paper in order to increase gas recovery and determine the key parameters of the reservoir for further development. To conduct a comprehensive study of the process under consideration, a computer model has been developed that is described by a differential equation with variable coefficients under corresponding initial and boundary conditions and moving boundaries. An arbitrarily defined region is converted to a standard one using the dummy region method. Functional dependences of the parameters of porosity and permeability are constructed by the method of local approximation given at some defined points in the reservoir for each nodal point. An algorithm is developed for solving the problem using the methods of longitudinal-transverse scheme and the flow option of the sweep method. The results are shown as isolines. In this paper, an attempt is made to prove that in the practice of fluid production it is advisable to introduce development technology based on inhomogeneous formation parameters. Numerical experiments have shown that using this technology wide opportunities appear for finding highly effective design solutions for fields development.
Development of a cluster analysis method for solving the problem of identifying static voltage load characteristics
Authors: Kondrashov Mikhail A , Popov Maksim G , Bukharov Dmitry S , Petrushin Denis E 
Published: May 2020

Abstract
Identification of static voltage load characteristics is not a trivial task. It is extremely difficult to develop a single methodology that will allow achieving the required accuracy results for any input data. The authors made an attempt to solve the problem, developed a method based on the use of methods for processing large data sets – BigData. One of the most important stages of this method is the stage of cluster analysis. The problem of choosing a method of cluster analysis also has nuances: it is necessary to maintain a balance between time and accuracy of calculations, while performing calculations with sufficient accuracy on various data. A number of domestic and foreign authors have investigated this issue, but the proposed options cannot be used in the developed methodology. The purpose of this research is to develop a cluster analysis method that will satisfy the above requirements. The author’s method is based on the k-means method. The main feature of the author’s method is the mechanism of initial generation of cluster centroids, which allows to exclude the influence of random generation of two-dimensional coordinates imperfection and to achieve uniform generation of initial clusters centers. The developed method was tested on a model problem with all known solutions, which can be easily verified analytically. Also the method was tested on actual industrial load data. The results obtained the requirements of accuracy and calculation speed and allow us to conclude that the developed method of cluster analysis can be used in the task of identifying static voltage load characteristics.
Mathematical model and computational experiments for the calculation of three-layer plates of complex configuration
Authors: Nuraliev F , Anarova Sh , Amanov O , Jumaev S , Abdirozikov O 
Published: May 2020

Abstract
Mathematical model and computational experiments to solve the problems of bending of three-layer plates of complex configuration are considered in the paper. Mathematical model and computational algorithm given in the paper are developed on the basis of the Hamilton-Ostrogradky’s variation principle, the Bubnov-Galerkin methods and the Rvachev R-functions. Numerical results of the problem are presented. Results are given in tabular and graphical form. Numerical studies of the results obtained are analyzed using the R-function method in combination with the Bubnov-Galerkin variational method to solve the problem of calculating the vibration of three-layer plates of complex configuration.
Research of one interpolation formula at creation of the finite-difference scheme for functions with internal zones of the bigger gradients
Authors: Panichkin A V 
Published: May 2020

Abstract
In work the method creation of the interpolation formula which is bringing closer function of the smoothing gap, meeting in solutions of one-dimensional tasks with a heatmass transfer is investigated. Interpolation on the basis of the decision for the smoothing gap is used for creation of finite-difference schemes to multidimensional tasks with ruptures of the first sort in boundary and initial and regional conditions. Use of additional knots with the constructed interpolation gives considerable reduction of approximating viscosity in finite-difference schemes for the convective and diffusive equations of transfer. For the constructed interpolation in case of existence of an internal interface which thickness less step of a regular grid is conducted an accuracy research at the asymptotic approximations in small parameters corresponding to changes of required function in the neighborhood of a thin interface.
The carried-out numerical calculations on a heat and mass transfer for a test task in two-dimensional rectangular area on the basis of the developed method show increase in an asymptotic order of accuracy of numerical decisions to the second from a grid step at application of the known schemes in the wide range of small parameter of diffusion.
Multi-Class Text Classification of Uzbek News Articles using Machine Learning
Authors: Rabbimov I M , Kobilov S S 
Published: May 2020

Abstract
A large amount of online news on various topics is being posted on the Internet. One of the tasks of processing this data is to provide the user with appropriate methods and tools for quick and easy search for important and interesting news. An approach to solve this problem is the reasonable distribution of news into respective classes. This increases the importance of automated classification of an electronic document section. In this paper, we consider the task of multi-class text classification for the texts written in Uzbek. The articles on ten categories were selected from the Uzbek “Daryo” online news edition and a dataset was developed for them. When performing multi-class text classification for this dataset, the following 6 different machine learning algorithms were used: Support Vector Machines (SVM), Decision Tree Classifier (DTC), Random Forest (RF), Logistic Regression (LR) and Multinomial Naïve Bayes (MNB). A detailed technological description of the stages of the proposed functional scheme of text classification and developed software is given. The TF-IDF algorithm and word-level and character-level n-gram models were used as the feature extraction methods. When defining hyperparameters for text classification, 5-fold cross-validation was used. Experiments were conducted and the highest accuracy was 86.88%. The models and methods that are proposed in this paper can be successfully used in the classification of texts written in the Uzbek language and further research in this area.
A generic algorithm for the word problem in semigroups and groups
Authors: Rybalov Alexander 
Published: May 2020

Abstract
Kapovich, Myasnikov, Schupp and Shpilrain in 2003 developed generic approach to algorithmic problems, which considers an algorithmic problem on “most” of the inputs instead of the entire domain and ignores it on the rest of inputs. Myasnikov, Ushakov and Won in 2008 constructed a simple generic algorithm for the word problem in some finitely defined semigroups, including classical semigroups with undecidable word problem: Tseitin semigroup, Makanin semigroup and Matiyasevich semigroup. But this algorithm does not work for wider classes of semigroups: for example, semigroups with one relation. In this paper we present new generic algorithm for a wide class of finitely defined semigroups, including Tseitin and Makanin semigroups, semigroups with one relation. This algorithm can be viewed as advanced development of the Myasnikov-Ushakov-Won algorithm. Also we adopt our generic algorithm for the word problem in some finitely defined groups, including classical examples of groups with undecidable word problem. The work is supported by Mathematical Center in Akademgorodok, the agreement with Ministry of Science and High Education of the Russian Federation number 075-15-2019-1613.
Numerical differentiation on the Bakhvalov mesh in the presence of an exponential boundary layer
Authors: Zadorin N A 
Published: May 2020

Abstract
The question of the application of formulas of the numerical differentiation of functions in the presence of the exponential boundary layer is investigated. The problem is that the application of classical formulas, wich are based on the differentiation of the Lagrange polynomial on the uniform mesh in this case leads to significant errors. It is proposed to study the formulas for derivatives on the Bakhvalov mesh, which is widely used in the construction of difference schemes for singularly perturbed problems. It is proved that applying of classical difference formulas for derivatives on a Bakhvalov mesh have error estimate that is uniform with respect to a small parameter. The results of numerical experiments are presented.
Computer simulating of nanoprocesses: Thermal jumps over a low barrier in the overdamped regime
Authors: Chushnyakova M V , Gontchar I I , Kuzyakin R A 
Published: May 2020

Abstract
We model numerically the process of a thermally activated decay of a metastable state over a low barrier in the overdamped regime. This process is typical for the recent nanoscale experiments reported in the literature. Within the framework of a novel unified computer code, two ways of modeling are applied: (i) the partial differential equation (Smoluchowski equation) and (ii) the stochastic ordinary differential equation (Langevin equation for the generalized coordinate). The advantages and disadvantages of both approaches are discussed and analyzed. Special attention is paid to the transient stage of the process yet the quasistationary stage is considered as well.
Investigation of interactions in the cenospheres-electrolyte system
Authors: Fedyaeva O A , Poshelyuzhnaya E G 
Published: May 2020

Abstract
The chemical composition of cenospheres have been studied by the methods of physical and chemical analysis. The products of their interaction with water and solutions of hydrochloric acid, sodium hydroxide and sodium chloride have been determined. It has been established that cenospheres dissolve in aqueous solutions regardless of pH. Pre-treatment of cenospheres in water and solutions of hydrochloric acid and sodium hydroxide reduces their dissolution in sodium chloride solution. Calcium ions, bicarbonate ions, silanol and aluminol groups of the surface participate in the ion exchange.
Influence of elastic characteristics of a track roller rim of a caterpillar system on the stress-strain state of an external rubber tire
Authors: Korostelev S A , Medvedev Yu V , Verbilov A F 
Published: May 2020

Abstract
The stress-strain state of the rubber tire of the track roller of the caterpillar mover is determined when considering the problem with an absolutely rigid rim and with an elastic rim. The effect of the rim elasticity on the radial stiffness of the track roller, on the distribution of contact pressure, and also on the distribution of the specific strain energy, which is a criterion for the fatigue strength of rubber, is shown. Two cases of the interaction of the track roller with the track are considered. The first case corresponds to the location of the axis of the track roller parallel to the chain link, the second case, when the plane of the track is located at an angle relative to the axis of the track roller. The influence of the angle of inclination of the support surface on the stress-strain state of the external rubber tire of the support roller is shown. The mechanical properties of a rubber tire are described by the elastic Treloar potential, the rim material of the track roller is considered linear elastic material.
Longitudinal waves in a cylinder with active external friction in a limited area
Authors: Sultanov Karim S , Khusanov Bakhtiyar E , Rikhsieva Barno B 
Published: May 2020

Abstract
The problem of longitudinal wave propagation in a cylindrical body in the presence of an incompressible external medium in a length limited area is solved in the paper in a one-dimensional statement. Along with the non-uniformity of motion, the friction force arising on the contact surface directly depends on the parameters of propagating waves. Numerical results are obtained using the finite-difference method according to the Wilkins scheme for axisymmetric problems. The results of wave propagation in a cylindrical body with a rigid external medium frame limited in length are presented. According to the calculation results, an increase in wave parameters (stresses and particle velocity) over time and with distance are observed as well as the causes of stress increase mechanism in the cylinder; the effect of external load parameters and physical-mechanical characteristics of the cylinder on the parameters of propagating waves are determined. Waves arising from active friction and reflected from the boundaries are revealed and the effect of location and length of external medium on changes in wave parameters in the cylinder is revealed.
Plasmonic Nanobiosensing: from in situ plant monitoring to cancer diagnostics at the point of care
Authors: Crawford Bridget M , Wang Hsin-Neng , Strobbia Pietro , Zentella Rodolfo , Pei Zhen-Ming , Sun Tai-ping , Vo-Dinh Tuan 
Published: May 2020

Abstract
Nucleic acid biosensing technologies have the capability to provide valuable information in applications ranging from medical diagnostics to environmental sensing. The unique properties of plasmonic metallic nanoparticles have been used for sensing purposes and among them, plasmonic sensors based on surface-enhanced Raman scattering (SERS) offer the advantages of sensitive and muliplexed detection owing to the narrow bandwidth of their characteristic Raman spectral features. This paper describes current applications that employ the unique SERS-based inverse molecular sentinel (iMS) nanobiosensors developed in our laboratory. Herein, we demonstrate the use of label-free iMS nanoprobes for detecting specific nucleic acid biomarkers in a wide variety of applications from cancer diagnostics to genetic monitoring for plant biology in renewable biofuel research.
Structure of multicorrelation sequences with integer part polynomial iterates along primes
Authors: Koutsogiannis Andreas , Le Anh , Moreira Joel , Richter Florian 
Published: May 2020

Let

T
T

be a measure-preserving

Z

ℓ

\mathbb {Z}^\ell

-action on the probability space

(
X
,

B

,
μ
)
,

(X,{\mathcal B},\mu ),

let

q
1

,
…
,

q
m

:

R

→

R

ℓ

q_1,\dots ,q_m\colon \mathbb {R}\to \mathbb {R}^\ell

be vector polynomials, and let

f
0

,
…
,

f
m

∈

L
∞

(
X
)

f_0,\dots ,f_m \in L^\infty (X)

. For any

ϵ
>
0

\epsilon > 0

and multicorrelation sequences of the form

α
(
n
)
=

∫
X

f
0

⋅

T

⌊

q
1

(
n
)
⌋

f
1

⋯

T

⌊

q
m

(
n
)
⌋

f
m

d
μ

\alpha (n) =\int _Xf_0\cdot T^{ \lfloor q_1(n) \rfloor }f_1\cdots T^{ \lfloor q_m(n) \rfloor }f_m\;d\mu

we show that there exists a nil- sequence

ψ
\psi

for which

lim

N
−
M
→
∞

1

N
−
M

∑

n
=
M

N
−
1

|

α
(
n
)
−
ψ
(
n
)

|

≤
ϵ

\lim _{N - M \to \infty } \frac {1}{N-M} \sum _{n=M}^{N-1} |\alpha (n) - \psi (n)| \leq \epsilon

and

lim

N
→
∞

1

π
(
N
)

∑

p
∈

P

∩
[
1
,
N
]

|

α
(
p
)
−
ψ
(
p
)

|

≤
ϵ
.

\lim _{N \to \infty } \frac {1}{\pi (N)} \sum _{p \in \mathbb {P}\cap [1,N]} |\alpha (p) - \psi (p)| \leq \epsilon .

This result simultaneously generalizes previous results of Frantzikinakis and the authors.
Characteristic class and the 𝜖-factor of an étale sheaf
Authors: Umezaki Naoya , Yang Enlin , Zhao Yigeng 
Published: May 2020

We prove a twist formula for the

ε
\varepsilon

-factor of a constructible sheaf on a projective smooth variety over a finite field in terms of characteristic class of the sheaf. This formula is a modified version of the formula conjectured by Kato and Saito in [Ann. of Math. 168 (2008), pp. 33–96].

We give two applications of the twist formula. First, we prove that the characteristic classes of constructible étale sheaves on projective smooth varieties over a finite field are compatible with proper push-forward. Secondly, we show that the two Swan classes in the literature are the same on proper smooth surfaces over a finite field.
Anointments and Prestige: Reflecting on #CommunicationSoWhite with Herman Gray and Oscar Gandy
Authors: Costley White Khadijah 
Published: May 2020

Abstract
Oscar Gandy, Jr. is a Professor Emeritus at the Annenberg School for Communication and a political economist. He is the author of four books, including Communication and Race: A Structural Perspective (1998), as well as numerous publications. Herman Gray is Professor Emeritus of sociology at UC Santa Cruz. He is the author of the books Watching Race and Cultural Moves, and many other scholarly writings. I spoke with both of them together about #CommunicationSoWhite, asking them as senior black scholars to reflect on contemporary discussions and suggest ways forward in the field of communication and media studies. 1 The interview is edited for brevity and clarity.