bluuebunny/crossref_metadata_2025_split huggingface dataset:
The derivation Cramer-Rao lower bound for parameters of signals multiplied on window functions
Authors: Altman E A , Vaseeva T V , Aleksandrov A V 
Published: February 2021

Abstract
The article focuses on the refinement of the Cramer-Rao lower boundary for the single-tone signal amplitude for estimation methods using window functions. The Cramer-Rao lower boundary allows finding the minimum variance of the signal parameter estimate. There are formulas for variances estimations of the amplitude, frequency, and phase of harmonics of harmonic signals, but the known methods for their finding, including algorithms based on the maximum likelihood method, show results above this boundary. The increased variance of the estimate occurs due to the application of window functions on the original signal. The estimation of the accuracy of the parameters harmonics in case using the window functions usually done with a numerical simulation. In the article, the authors derive a formula for the minimum variance for amplitudes of harmonics in the case of the using the window functions. This derivation allows us to understand the mathematical meaning of the broadening the Cramer-Rao lower boundary when using window functions, and the resulting formula brings a faster and more accurate estimation of an amplitude accuration, in comparison with numerical simulation. According to the results of the experiment the calculations by the proposed formula and the numerical experiment data are the same.
Symmetry algebra of the time-dependent Schrödinger equation in constant and uniform fields
Authors: Boldyreva M N 
Published: February 2021

Abstract
The problems of constructing the symmetry operators of the time-dependent Schrödinger equation in the constant and uniform electric and magnetic fields with the use of the obtained operators in the method of non-commutative integration of linear differential equations are considered. A system of defining equations for the first-order symmetry operators is written. The paper investigates the structure of the symmetry algebras. It is shown that in the case of electric field the resulting algebra is the deformation of the Schrödinger algebra sch(1, 3).
On the greatest distance between two partitions of the finite set
Authors: Dronov S V 
Published: February 2021

Abstract
Consider the family Ξ of all possible partitions of a given finite set into disjoint parts. Suppose we have A ∈ Ξ, and there is reason to consider this partition basic from a certain point of view. The greatest value d *(A) of the special cluster metric d(A, B) is found, which is reached when its second argument runs through all B ∈ Ξ. The value of d *(A) turns out to depend on the structure of the basic partition A. Using the found value of d *(A), we propose a numerical coefficient whose value allows us to estimate the degree of difference between the basic partition and the newly built one. Such an assessment can help us to make a decision about the possibility of using the new partition instead of the basic one.
Unsteady temperature field calculation in the exothermic reaction
Authors: Fedorov S V , Tolstukha A S , Fedorov I V , Zhukovskyy V V 
Published: February 2021

Abstract
The paper presents the exothermic reaction monitoring method used in solving the thermal conductivity problems as well as in the process of solidifying the concrete foundation. The finite element method was applied. The problem was solved in a three-dimensional model taking into consideration the thermal characteristics dependence during the process of concrete hardening. The unsteady temperature field of the foundation block was calculated taking into account the forced pipe cooling. The given methodology is implemented in software and used for performing the three-dimensional unsteady temperature calculations. The software “Temper–3D” having a compliance certificate was developed according to the mentioned methodology. The program was registered in the Computer Software Register.
Differential equations application in progress prognosis of the pyrogenic succession process of grass and shrub layer of pine forest
Authors: Moskvitin A V , Goltyapin V V 
Published: February 2021

Abstract
This article is devoted to the differential equations system application of the Morino – Voight mathematical model for predicting the process of pyrogenic succession of a pine forest. For the first time, the results of predicting the process of pyrogenic succession according to the Morino – Voight model were compared with real data characterizing the restoration of a pine forest after a fire.
Car Service Optimization Based on Simulation
Authors: Revina I V , Trifonova E N 
Published: February 2021

Abstract
The article presents the results of optimizing the service center operation. The IDEF3 notation was used to analyze the logical sequence of processes performed in the car center divisions. The developed discrete-event simulation model “AS-IS” made it possible to identify “bottlenecks” in the work of the car center. The involvement of experts and the use of the method of apriori ranking of factors allowed determining the impact of a number of factors on the work of the service center and the directions for improving the work. Changes in organizational, material and technical factors and the development of “TO-BE” simulation model allowed determining the optimal parameters for the service center operation. As a result of the business process reengineering, the following changes were made: staff schedule and assignment of employees to work; the number of service posts; an electronic queue and document management system. These changes allowed increasing the profit of the service center by 1.9 times.
Computer-aided simulation of high-dimensional event-continuous systems
Authors: Shornikov Yu V , Popov E A 
Published: February 2021

Abstract
A comparative analysis of efficiency of explicit methods with error and stability control, semi-implicit (m, k)-methods, and implicit methods implemented in the modelling and simulation environment ISMA is presented. The Akzo Nobel Central Research laboratory’s model of a tumour penetrated by antibodies is used as the test problem. The computer model in the LISMA language after applying the method of lines is given. Performance of the numerical integration algorithms is measured for different spatial variable discretization steps.
Equational noethericity for graphs and hypergraphs
Authors: Treier Alexander 
Published: February 2021

Abstract
In 1999th G. Baumslag, A. Miasnikov and V. Remeslennikov posted the following problem. Let G be a group. Does a noethericity by equations in one variable imply a nothericity by equations for the group G in the language with constants from G? Same question may be asked for graphs and hypergraphs. It is shown in the article that the answer to the question above is positive for graphs and is negative for hypergraphs.
Two-grid method for the stationary Burgers equation
Authors: Zadorin N A , Shagaev S B 
Published: February 2021

Abstract
A two-grid method is investigated for solving the boundary value problem for nonlinear ordinary differential equation of the second order with a small parameter at the highest derivative. The solution to the problem has large gradients in the boundary layer region. The application of the central difference scheme on the Shishkin and Bakhvalov grids is investigated. Previously, this scheme was investigated only in the case of a linear equation. It is shown that in the case of the considered nonlinear problem, this scheme on the Shishkin and Bakhvalov grids has a convergence uniform in a small parameter. On the basis of computational experiments, it is shown that the use of the two-grid method leads to a reduction in computational costs when implementing the difference scheme. It is shown that in the two-grid method it is effective to apply the Richardson method to improve the accuracy of the difference scheme.
Fuzzy Discrete Problems with Summed Objective Function and their Crisp Bi-Objective Modifications
Authors: Zakharov A O , Kovalenko Yu V 
Published: February 2021

Abstract
Discrete optimization problem with fuzzy input parameters having the form of triangular fuzzy numbers is considered. Objective function is given by the sum of some subset of fuzzy input data. Crisp model with two criteria: objective function and its membership function is formulated. We propose an algorithm which constructs the Pareto set of this bi-criteria problem. We consider particular fuzzy discrete problems, such as scheduling problems, routing problems, problems of selecting a subset of elements, maximum matching problems, where the obtained results could be applied.
Optimization of the control system parameters using the genetic algorithm
Authors: Denisova L A , Alekseytsev D M , Meshcheryakov V A , Denisov O V 
Published: February 2021

Abstract
The method for parametric optimization of an automatic control system is proposed. The criterion for the quality of the functioning of the system includes control accuracy and control costs. The method takes into account the change in the operating conditions of the control object and the influence of random disturbances. A combination of a genetic algorithm procedure in MATLAB and system simulation in Simulink is proposed. Recommendations for choosing the optimal values of the system parameters are passed on to the operator of the technological process.
Multistage biquadratic filter for measuring of electrical power consumption parameters
Authors: Gordeev O I , Zakharenko V A 
Published: February 2021

Abstract
The relevance of developing technical solutions to reduce the number of calculation operations and the amount of memory required for the operation of typical structural elements of programs that implement digital signal processing in problems of continuous measurement of electrical parameters is shown. The use of the multi-stage biquadratic filter for solving these problems is proposed. The theoretical comparison of the structure of the above-mentioned filter with the known structures of digital filters is carried out. An experimental comparison of a specific implementation of the multi-stage biquadrate filter with the similar implementation of a digital filter of a known structure is carried out.
Recognition of micro-objects with adaptive models of image processing in a parallel computing environment
Authors: Jumanov I I , Djumanov O I , Safarov R A 
Published: February 2021

Abstract
Scientific and methodological foundations for optimizing the processing of micro-objects, in particular, pollen grains, have been developed on the basis of models and methods of preliminary information processing with mechanisms for filtering, identifying, and using textural, specific characteristics, and geometric features of images. The efficiency of image filtering mechanisms is investigated based on the use of statistical control rules, adaptive two-threshold control, trend functions, and control of the contour description error, traditional detectors of random noise, and interference. The mechanisms of image identification using biquadratic, orthogonal algebraic polynomials, 4th order splines are proposed. A technique for optimizing image identification by finding a function by its integrals in a family of straight lines based on the Mellin and Fourier transforms has been developed. Combined models with mechanisms for smoothing reference points, segmentation of contours, filtering with detection of changes in dynamics, optimization by the conjugate gradient method, time relaxation have been built. A software complex for the recognition and classification of images of pollen grains in C ++ has been developed, which includes testing identification algorithms based on the Daubechies spline function, orthogonal algebraic polynomials of 4, 8 orders in the parallel computing environment “CUDA”.
Using computer simulation in designing new products
Authors: Kramorov A V , Yanishevskaya A G 
Published: February 2021

Abstract
Design of new products and mechanisms is continuous and complicated process. The complexity of new products is explained by increased requirements for reliability and wide functionality of new products for its competitiveness. At the same time, design time is reduced by replacing natural tests with computational experiments and the widespread use of modern computer-aided design systems (CAD systems). This article presents the design of the bridge laying mechanism of tank bridge layer using modern CAD systems.
Search for the optimal method for obtaining estimations for an automated magnetotelluric signal processing system
Authors: Lavrukhin A A , Lobov K V , Tukanova A S , Onufriev A S 
Published: February 2021

Abstract
The problem of obtaining estimates of impedance frequency characteristics in the magnetotelluric sounding method is considered. A variational algorithm is proposed for research through a variety of means of estimation from the point of view their accuracy and efficiency. The results of computational experiments on the processing of synthetic signals are presented, which represent indicators of the accuracy and efficiency of some estimation methods. The proposed approach can be used in the development of algorithms and software for the embedded system for recording and processing signals, as well as applied software for an automated system for processing signals from magnetotelluric sounding method.
Passive orientation of the parts in the mechanical disk hopper feeding device with an annular orientator and radial grooves
Authors: Pantyukhina E V , Preis V V , Pantyukhin O V 
Published: February 2021

Abstract
The paper considers mathematical models describing the process of passive orientation of axisymmetric parts in the form of the bodies of rotation with implicit asymmetry at the ends in the mechanical disk hopper feeding device with an annular orientator and radial grooves made on a rotating disk. The developed mathematical models make it possible to estimate the boundary conditions under which the reliable orientation of the parts and the time of orientation of the parts will be ensured, depending on the geometric parameters of the part, the coefficient of sliding friction of the part against the guide surfaces, the structural and kinematic parameters of the hopper feeding device.
Improving the accuracy of homing mobile objects with semi-passive method by reducing the time of forming the control force
Authors: Pavlov V I , Belousov O A , Dorokhova T Y , Belyaev M P , Trapeznikov E V 
Published: February 2021

Abstract
The options of relative motion of a homing object with a semi-passive method and a mobile end waypoint are considered. For the given options, estimates for the required transverse acceleration of the homing object and the miss distance are given. It is shown that to reduce the miss in homing by method of proportional guidance it is advisable to reduce the time for the control force formation, and the decrease of distance of switching off the control system, when in the object control system only angular information about the current position of the end way points and motion parameters of their own mass center is used.
Features of the CIE76, CIE-94, and CIE-2000 methods that affect the quality of the determining process of the image average color
Authors: Proskuriakov N E , Yakovlev B S , Arkhangelskaia N N 
Published: February 2021

Abstract
Results of pilot studies of the difference in color – the indicator of Delta E determined by CIE-76, CIE-94, CIE-2000 at determination of average color of the digital image are provided. Based on experimental data features of behavior of CIE-76, CIE-94, CIE-2000 calculators on condition of their use for determination of average color of different graphic formats of images were revealed. The research showed that CIE-76 has always the greatest values of the indicator of Delta E. It is revealed at all studied formats of images, irrespective of the prevailing color on the image. In addition, it was established that CIE-94, CIE-2000 show very insignificant deviations from each other and significantly differ from Delta E’s indicators of CIE-76 at stages of the maximum reduction of the image. In the analysis of graphic dependences of behavior of the indicator of Delta E it was revealed that CIE-76, CIE-94, CIE-2000 behave probably, saving the main peaks of values. The software in the Python programming language, which showed the efficiency and capability, was developed to measure average color at different images.
Features and consistent patterns of changes in properties of the system AIIIBV - ZnTe solid solutions
Authors: Kirovskaya I A , Novgorodtseva L V , Vasina M V , Mironova E V , Nor P E , Yurieva A V , Chernous N V , Zhigarova O Yu , Krasheninin V I 
Published: February 2021

Abstract
By the methods developed for the InSb-ZnTe, GaSb-ZnTe systems, in the regions of mutual solubility of the initial binary compounds (InSb and ZnTe, GaSb and ZnTe), solid solutions (InSb)x(ZnTe)1-x, (GaSb)x(ZnTe)1-x have been obtained.
X-ray, IR and Raman spectroscopic, electrophysical studies of the obtained solid solutions (in comparison with the initial binary compounds and among themselves) have been carried out, following the results of which the obtained solid solutions have been certified as substitutional solid solutions with a cubic sphalerite structure. The information on multicomponent diamond-like semiconductors has been expanded.
The acid-base properties of the InSb-ZnTe, GaSb-ZnTe systems components surfaces, varying in composition from weak acid to weakly basic, have been studied.
General and distinctive features in the “behavior” of the InSb-ZnTe, GaSb-ZnTe systems solid solutions have been revealed. The relative influence of binary components on the type of dependences “property – composition” has been demonstrated and explained.
Practical recommendations have been given for the use of solid solutions with the lowest pHiso values as materials for the manufacture of sensors for main gases trace contamination.
Analysis of the geometric features of T-x-y diagrams with melt immiscibility for silicate systems
Authors: Vorob’eva V , Zelenaya A , Lutsyk V 
Published: February 2021

Abstract
Analysis of the geometric structure of phase diagrams for ternary systems with the two immiscible liquids has been carried out. T-x-y diagrams with the both types of the monotectic equilibriums (univariant and invariant ones) have been analyzed. Three-dimensional computer models of T-x-y diagrams for the four silicate systems with mono- and invariant equilibriums and different variants of the immiscibility surfaces location have been built. T-x-y diagram of the ZrO2-SiO2-Al2O3 system includes one immiscibility cupola, located in the ZrO2 crystallization field, which adjoins the ZrO2-SiO2 side. The 3D model of T-x-y diagram includes four invariant transformations: peritectic P: L+ZrO2+SiO2→R2, quasi-peritectic Q: L+ZrO2 →R1+R2, two eutectic E1: L→ZrO2+Al2O3+R1, E2: L→SiO2+R1+R2. Five surfaces of liquidus, which correspond to the beginning of primary crystallization of three initial components and two binary compounds R1=3Al2O3·2SiO2 and (congruently melting) and R2=ZrO2·SiO2 (decomposed without liquid) are formed in the system. T-x-y diagram TiO2-ZrO2-SiO2 is characterized by one eutectic E: L→TiO2+SiO2+ZrO2·TiO2 and one quasi-peritectic Q: L+ZrO2→SiO2+ZrO2·TiO2 transformations and includes two immiscibility surfaces from the sides of TiO2-SiO2 and ZrO2-SiO2 binary systems. FeO-SiO2-Fe2O3 system with common immiscibility cupola, that prolongs from the system FeO-SiO2 to the system SiO2-Fe2O3, is characterized by three invariant transformations of eutectic type, and one metatectic transformation V: B1 →L+B2+C, which corresponds to the transfer from high-temperature allotropy of silica (B1 - cristobalite) to the low-temperature one (B2 – tridymite). T-x-y diagram KAlSi2O6-Fe2SiO4-SiO2 has two immiscibility surfaces: one of them adjoins to the Fe2SiO4-SiO2 binary system and the second one is located on the Fe2SiO4 and tridymite liquidus surfaces, dividing the univariant curve on their boundary into two parts, and has three points of the maximum and three points of the minimum. Using of the computer models of T-x-y diagrams allows you to take into account different variants of the geometric structure of the investigated silicate systems.
Hot spots of opportunity for improved cropland nitrogen management across the United States
Authors: Roy Eric D , Hammond Wagner Courtney R , Niles Meredith T 
Published: February 2021

Abstract
Nitrogen (N) is a vital input to crop production, but its excess use is a cause of environmental and human health problems in many parts of the world. In the United States (US), as in other nations, reducing N pollution remains challenging. Developing effective N policies and programs requires understanding links between cropland N balances (i.e. N inputs minus N harvested in crops) and potential contributing factors. We present novel insights into these links using a national county-level assessment and propose a criteria-scoring method to inform US N policy and programs. First, we characterize cropland N balances across the US in 2011–2013 and identify counties (∼25%) where N input reductions are less likely to result in crop yield declines. Second, we identify agronomic, environmental, social, demographic, and economic factors correlated with N balance, as well as counties that are underperforming based on these characteristics. Finally, we employ criteria scoring and hot spot analysis to identify 20 spatial clusters of opportunity for improved cropland nitrogen management. These hot spots collectively account for ∼63% of total surplus N balance for croplands but only ∼24% of cropland area in the US. N flows for these hot spots indicate variable opportunities across the US landscape to improve cropland N balances by reducing N fertilizer use, better managing manure N, and/or increasing N use efficiency. These findings can guide future efforts to integrate N balance into regulatory and voluntary frameworks in US policy and programs.
Intelligent Regulation System of Central Heating Pipe Network based on Internet of Things
Authors: Chen Yiming , Du Xiaogang , Liu Yuhang , He Jiang , Chen Wenli 
Published: February 2021

Abstract
The level of heating quality determines the comfort level of residents’ indoor life in winter. In order to effectively improve the hydraulic imbalance of the pipe network, improve the self-adjusting ability of the pipe network and reduce manual operations. This paper proposes an Intelligent Regulation System for Centralized Heating Pipe Network based on the Internet of Things, and takes the No.3 building of Guangxian Jiayuan Community in Tianjin as a pilot project to select the flow rate and return water temperature in front of the representative users in the low, middle and high floors Measure the date and analyze it. The results show that the flow of the indoor pipe network of the user runs smoothly, and the change range is within 0.05 m3/h, and the change range of the return water temperature of the pipe network is maintained within 3 °C. The Intelligent Regulation System of the Pipe Network has a good self-regulation capability.