bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of COVID - 19 from Chest CT Images using a Deep Neural Network with SVM Classification
Authors: Akshitha B , Arthi M , Brindha R , Sandhya G 
Published: June 2021

Abstract
Coronavirus is a quickly spreading viral illness that taints people; however, creatures are likewise to be contaminated because of this infection. The day-by-day life of people, their wellbeing, and the economy of a nation are influenced because of this lethal viral infection. A clinical investigation of COVID-19 contaminated patients has demonstrated that these kinds of patients are generally tainted from lung disease in the wake of interacting with this sickness. Chest X-beams (i.e., radiography) and chest CT are a more viable imaging strategy for diagnosing jump related issues. All things considered, a significant chest X-beam is a cheaper cycle in contrast with chest CT. Yet chest CT has more degree of accuracy. Profound learning is the best method of AI, which gives valuable examination to contemplate a lot of chest CT pictures that fundamentally affect the screening of COVID-19. This type has taken the Physician Assistant (PA) perspective on chest CT filters for Coronavirus influenced patients just as solid patients. After tidying up the pictures and applying information increase, the proposed system utilized profound learning-based SVM models and analyzed their exhibition.
Lifetime Prediction of Lithium-Ion Battery Using Machine Learning For E-Vehicles
Authors: Venugopal D , Pranav V Sharan , Lakshmi B Swathi , Vishnu K 
Published: June 2021

Abstract
A life cycle of battery with long testing time and without contact measurement devices will be applicable for industrial applications. To this problem, the solution for potential will be provided by the combined technique of supervised learning and infrared thermography. The focus of the research will be on machine learning techniques. Artificial neural networks (ANNs) and support vector machines (SVMs) are used in conjunction with thermography to estimate the life cycle of lithium ion polymer batteries. The capturing of infrared images at 1 frame per minute and charging of 70 minutes followed by the discharging of 60 minutes for 410 cycles. For ANN and SVM models the input nodes of charging or discharging use the surface temperature profiles. The input will be in thermal profile for the result. Under 10 minutes of testing time, we can estimate the current life cycle of a studied cell with an error of less than 10%. In SVM the accuracy will be similar while comparing with ANN but the testing time will be longer.
Study of the noise sources of an UAV with a two-stroke engine and shrouded propeller
Authors: Moshkov P A , Samokhin V F , Yakovlev A A 
Published: June 2021

Abstract
The widespread use of unmanned aerial vehicles poses the task of ensuring their low noise. To solve the problem of designing low-noise unmanned aerial vehicles, it is necessary to have data on the structure of the sound field of various unmanned aerial vehicles and their main noise sources. The results of an acoustic characteristics study of an unmanned aerial vehicle are presented. Its power plant includes a two-stroke piston engine and 4-bladed shrouded pusher propeller. The tests were performed in a wind tunnel at different speeds of the incident flow and different power conditions of the power plant. The dominant source of drone noise is a two-stroke piston engine. The propeller contribution is observed in the second and fourth tones in the radiation spectrum.
Modification of the Cu-Zr bronze surface by exposure to powerful UV laser pulses
Authors: Malinskiy T , Mikolutskiy S , Rogalin V , Khomich Yu , Kaplunov I 
Published: June 2021

Abstract
The laser pre-treatment of Cu-Zr alloy surface for diffusion welding, which is used in the aerospace industry for joining dissimilar materials, has been investigated. The effect of a nanosecond UV laser pulse on the surface of Cu-Zr alloy samples was studied. It was found that at a pulse energy density E ∼ 0.2-1 J/cm2 pre-ablative microscopic effects of mainly thermal nature were observed in the metal, also there were uplifts of material in the irradiated zone. The surface profile of the sample in the irradiated zone corresponds to the energy distribution of the laser beam. Significant deformations occurred in the crystal structure of the surface layer, and an irreversible configuration of the metal surface was created. At E ≥ 1 J/cm2 an optical breakdown with the formation of a plasma torch and with the appearance of a classical laser crater was observed. The arising erosion of the surface prevented registration of this effect. Microanalysis showed that the concentration of zirconium in the surface layer of the metal after exposure decreased.
Aircraft composite structures integrated approach: a review
Authors: Pogosyan M , Nazarov E , Bolshikh A , Koroliskii V , Turbin N , Shramko K 
Published: June 2021

Abstract
This paper presents a comprehensive program for modelling airframe structures made of composite materials using the finite element method. The purpose of this study is to apply the comprehensive approach to the creation of models in accordance with the main directions of numerical modelling. The “computational and experimental research pyramid” and its relationship with the complex modelling program are presented. Methods for calculating aggregates and structures using micromechanics, static, dynamic and resource strength methods are described, as well as the influence of the manufacturing cycle on the final performance of a product made of a composite material. This integrated approach allows one to optimize all the stages in the design process of the aircraft. Using this approach, one can replace part of the certification tests with modelling according to the “computational and experimental research pyramid”, which will reduce the cost of certification tests.
Optimal calibration plan for inertial measurement unit based on microelectromechanical system
Authors: Krylov A A 
Published: June 2021

Abstract
This paper is about the composition of scientifically substantiated calibration plan from the specific requirements for inertial measurement unit on microelectromechanical sensors. It is proposed to decompose the common problem into three tasks – converting implicit requirements to the explicit requirements with error components, determining of requirements by indirect parameters and finding direct parameter values, time limited calibration that have limits for full time. All these tasks may be presented as multi-criteria optimizations and be solved by numerical methods with some semi-analytical substitutions. Suggested methods are useful for composing an optimal calibration plan in conditions of ambiguous requirements, to estimate reaching accuracy, test volume and total calibration time. This approach offers the researcher a new look at the problem of balance between calibration accuracy and optimal use of resources.
Optimization of the mean-square approximation procedures for iterated Ito stochastic integrals based on multiple Fourier-Legendre series
Authors: Kuznetsov D F , Kuznetsov M D 
Published: June 2021

Abstract
The article is devoted to optimization of the mean-square approximation procedures for iterated Ito stochastic integrals of multiplicities 1 to 4 based on multiple Fourier-Legendre series. The mentioned stochastic integrals are part of strong numerical methods with convergence orders 1.0, 1.5, and 2.0 for Ito stochastic differential equations with multidimensional non-commutative noise. We show that the lengths of sequences of independent standard Gaussian random variables required for the mean-square approximation of iterated Ito stochastic integrals can be significantly reduced without the loss of the mean-square accuracy of approximation for these stochastic integrals.
Technique of constructing a measuring base for determining the azimuthal attitude of the dynamic test-bench Actidyn “ST2356C”
Authors: Zimin R , Veremeenko K 
Published: June 2021

Abstract
Calibration of inertial sensors is one of the most important tasks in the development of inertial navigation systems. The solution to this problem is impossible without achieving the required level of accuracy of dynamic modeling test-benches used in their development. The paper describes a technique of constructing a measuring base for determining the azimuthal attitude of the precision dynamic test-bench. This techniques used industrial geodesy technologies for providing ability to calibrate all major types of modern inertial measuring units in a wide temperature range. The azimuthal attitude determining is based on measuring the angular attitude of the mirror placed on the test-bench’s turntable by an autocollimation measurements technique by using a high-precision reflectorless total station, the coordinates of which are determined by rangefinder-goniometric measurements to reflectors with known coordinates, mounted on the room’s walls. The calculation results shows that proposed technique of constructing a measuring base allows to ensure the measurement accuracy for carrying out research and calibration of highly accuracy inertial measuring systems.
The Semi-Markov model of operation and maintenance of gas analytical system
Authors: Bobkov V , Kanishchev O , Men’shova I 
Published: June 2021

Abstract
Gas analytical systems are one of the key elements for the safe operation of airports and ground airspace infrastructure facilities where there is a risk to life or property caused by the possible combustible gases leaks. The gas analytical systems provides safety operation of airspace infrastructure facilities through the early detection of combustible gases and the issuance of warning signal; therefor the gas analytical systems is imposed high operational reliability requirements ensured by an optimal maintenance strategy. Known methods of maintenance management could not consider operation features and gas analytical systems structure complexity therefore increase cost of maintenance of airspace infrastructure facilities. The developed semi-Markov model of operation and maintenance of gas analytical systems, which takes into account the frequency and duration of control, the intensity of operation, the reliability of components, quantity of the spare parts and the gas analytical systems complexity makes it possible to design optimal maintenance strategy and therefore to reduce the cost of maintenance of ground airspace infrastructure facilities by reducing insupportable wear out of gas analytical systems and to reduce capital expenditures by excluding an excessive amount of the spare parts.
Improvement of projection-based LiDAR data segmentation algorithms using object-contextual representations
Authors: Stokolesov M , Yudin D 
Published: June 2021

Abstract
Nowadays self-driving cars and such unmanned aerial vehicles as drones are one of the most actively developed technologies, where machine learning algorithms play an irreplaceable role especially in the perception problem, which is the context of this research. To be applicable in self-driving cars and especially drones such algorithms should not only have good output quality, but also be real-time. For this reason, in the case of LiDAR data segmentation problem we pay special attention to algorithms that are based on point cloud projections because of their speed superiority over other heavy algorithms that process input point cloud directly. The main drawback of projection-based algorithms is their lower segmentation accuracy, so in this paper we show that it can be improved by integrating contextual representation module inside segmentation algorithm architecture. In our work we consider SalsaNext as a segmentation algorithm and OCR as a context representation module because these methods are among the highest in the corresponding datasets’ leaderboards. We provide results from quantitative evaluation on the Semantic-KITTI dataset, which demonstrate that the proposed SalsaNext modification gives 6.2% mean intersection over union metric improvement with no speed reduction.
Engineering of modernization of high technology products based on the concept of strategic risk
Authors: Burdin S , Moskvicheva N 
Published: June 2021

Abstract
The analysis showed that the most important results of the Aviation Industry Development Strategy are: an increase in the share of Russian manufacturers of aviation products in the world market; reorientation of the production of aviation industrial complex to the innovative segment of the global market. The aim of the study is to develop an engineering mechanism for the modernization of science-intensive products of the aviation industry. In accordance with this, a method is proposed for assessing the strategic risk of high technology products, a model for assessing the effectiveness of modernization of high technology products based on the concept of strategic risk as defining elements of the engineering process in the aviation industry. The practical implementation of the model is carried out.
Determination of the composite’s representative volume for longitudinal tensile test simulations
Authors: Turbin N , Kalutskiy N 
Published: June 2021

Abstract
In this study the proper size of the composite material’s representative volume element is addressed. Longitudinal tensile test simulations are conducted for a range of sizes and several variants of material models for matrix, fibre and interface. It is found, that matrix and interface degradation with prescribed properties do not influence the value of failure engineering stress for the cell in comparison with model, where only fibre damage model is set, and the adequate size of the cell is shown to be 80 µm. In contrast, variant contained stochastic fiber strength distribution shows different value for engineering failure stress and strain and suggests larger size of the material cell for simulations. Received results might be useful for accurate micromechanical modelling of material testing.
Attitude determination in integrated GNSS-inertial navigation systems in information and measurement insufficiency conditions
Authors: Zharkov M V , Veremeenko K K , Kuznetsov I M , Pronkin A N 
Published: June 2021

Abstract
The article presents the attitude determination algorithm for multi-antenna global navigation satellite and inertial integrated navigation system operating under information and measurement insufficiency conditions. The information and measurement insufficiency conditions are understood as the impossibility of the inertial system alignment on a fixed base and the absence of a redundant number of satellites to resolve the carrier phase integer ambiguity. The ability of the navigation system to operate in such conditions is achieved by combining several existing attitude determination methods and using the new method of attitude determination using ambiguous satellite phase measurements and absolute angular rate measurements. The hardware-in-the-loop simulation results using a 2-axis motion simulator and microelectromechanical systems inertial sensors are presented. The results confirm the efficiency of the proposed approach to the design of the navigation system algorithm.
Research and optimization of axial gas forces in turbines of turbojet bypass engines with afterburner combustion chamber
Authors: Malinovsky I M , Nesterenko V G , Ivanov I G 
Published: June 2021

Abstract
The paper presents the results of research and analysis of the efficiency of the power systems of the rotor of the gas generator of modern bypass engines with an afterburner. It was revealed that the gas axial forces, which are the difference between the axial forces of the rotors of the high-pressure compressor and its turbine, acting on the front angular contact bearing of the gas generator, can be significantly reduced in order to increase their reliability and service life.
Methods for flexibility determination of bolted joints: empirical formula review
Authors: Eremin V , Bolshikh A , Koroliskii V , Shelkov K 
Published: June 2021

Abstract
In this work, a comparative analysis of existing methods for determining the compliance of mechanical joints such as ‘composite-composite’ and ‘composite-metal’ is performed. Polymer composite materials are widely used in modern aircraft industry. As a result, it is necessary to take into account the characteristics of joints of composite aggregates with composite and metallic ones. Considering the compliance of connections in the global finite element models of structural units of aircraft allows increasing the accuracy of calculations. The use of empirical formulae can significantly reduce time and labour costs in calculating the compliance of bolted connections for use in global finite element models. In this paper we review and analyse the existing empirical dependencies. Calculation of rigidity and compliance of single-shear ‘composite-composite’ and ‘composite-metal’ joints by finite element method for small, medium and large membrane thicknesses is carried out, and the results are compared with the calculations using empirical formulae. As a result of the analysis for medium and small thicknesses it is proposed to determine the value of bolted joint flexibility by the empirical formula Boeing 1, and for large thicknesses of connecting membranes it is proposed to use empirical formula Huth.
Development of a methodology of estimating limits of oscillations of optical system of photoelectric rotary encoders
Authors: Korolev I , Chekin A 
Published: June 2021

Abstract
The development of optical sensors with rotating mechanism requires estimation of oscillations limits. Although some work has been done on to linear encoders, there’s no information on such approaches related to rotary encoders. This manuscript proposes a computational approach of estimating oscillations limits of optical systems of rotary encoders. The approach is based on machine computations of waveforms modified by shifting position of one of discs, and rotates not around main axis of optical system. For estimations of oscillations during computations, one of optical discs translated against optical axis of optical system to perform occlusions, accounting differences in light distribution with oscillations presented. As the result of applying of methodology, computer program described and tested to calculate limits of hypothetical optical system, as well as its predictions were confirmed by comparison with behavior of real rotary encoder. This data was achieved with fewer computations, compared to classical calculation methods of light propagation. Developed methodology allows creating computer programs for estimating limits of oscillations within reasonable timeframe.
Study of BPF pressure pulsations reduction in centrifugal bladed machines using splitters
Authors: Klimenko D , Kondratov A , Timushev S , Li J 
Published: June 2021

Abstract
Presence of intensive pressure pulsations and noise on blade passing frequencies is a characteristic feature of all types of centrifugal bladed machines including pumps. Under definite conditions pressure pulsations can reduce the pump reliability and life cycle. High level of tonal noise can be inappropriate due to ecological requirements. The paper is devoted to the study of application of splitters for reduction of pressure pulsations in centrifugal pumps. 2D and 3D numerical methods are used in the study. Initial computational tests were performed with a two-dimensional formulation for a centrifugal pump with a simple volute using 2D discreet vortex method for the impeller flow and 2D acoustic-vortex approach for pressure pulsations prediction. 3D unsteady flow computations of an air model of the centrifugal pump are undertaken with the impeller having splitters. Calculations of pressure pulsations show that the use of additional blades reduces the amplitude of the first harmonic of blade passing frequency by more than three times compared to the design without splitters. It correlates with flow parameters distribution along the impeller outlet diameter that has less nonuniformity and a more balanced vorticity profile. Application of splitters reduces the amplitude of pressure pulsations by a factor of 3.
Prediction of the structural state in a wheel forging based on computer modeling
Authors: Ovchinnikov A V , Pchelnikov A V 
Published: June 2021

Abstract
The landing gear of any flying vehicle is a unit of increased responsibility. The entire load during take-off and landing is perceived by the wheels of the landing gear. The reliability of aircraft wheels is determined, among other things, by the distribution uniformity of the structure and mechanical properties over their volume. This work represents a method for predicting the structural state in stamped forging of an aluminum alloy wheel included in the chassis of a small bomber. Based on the simulation results (deformation temperature and deformation rate), the cause of grain growth in the area of the wheel rim is determined. Using the structural state diagrams of Vainblat Yu M. It is shown that a region with coarse grains in the rim is formed due to local recrystallization during heating for quenching. Based on analysis of temperature-speed conditions in coarse-grained area, stamping modes are proposed with stepwise reduction of deformation rate at the final stage of the process, which excludes recrystallization.
Influence of adhesive bond line thickness on joint strength of composite aircraft structures
Authors: Kostin V , Nasonov F , Zinin A 
Published: June 2021

Abstract
Methods for assessing the effect of the thickness of the adhesive layer in the adhesive joint of thin-walled composite structural elements on the strength of the entire joint are considered; a critical analysis of existing theoretical methods for predicting the strength of adhesive joints is given. The contradiction between the theoretical estimates of the effect of the adhesive thickness on the strength and the results of experiments and practical experience in the use of adhesive joints of composite panels is established. It is revealed that the most effective methods for predicting the load-bearing capacity of adhesive joints are energy models of fracture mechanics based on the intensity of the release of fracture energy and the formation of a pre-fracture zone in the adhesive layer. Assuming the determining role of changes in the size and shape of the initial fracture zone depending on the thickness of the adhesive layer, the results of the prediction of the strength of the adhesive joint are compared with experimental data.
Analysis of the geometric parameters influence on the labyrinth seals performance
Authors: Androsovich I , Borovikov D , Siluyanova M 
Published: June 2021

Abstract
One of the ways to improve the modern gas turbine engines efficiency is to increase the efficiency of its components. An increase in the gas turbine engine components efficiency may be achieved by reducing air leaks by the seals usage. It is possible to achieve a reduction in air consumption through the seal, including off-design operation conditions, by using modern methods of computational fluid dynamics simulations. One of the possibilities of modern computational fluid dynamics methods is to analyze a simultaneous effect of the large number of variable design parameters. Performance of different labyrinth seals type is analyzed. Direct-flow labyrinth seal is chosen as most common in jet engine design due to its properties. Geometric parameters influences are defined. Optimization resulted in a labyrinth seal configuration that achieves a 20% reduction in seal mass flow. A comparison of the mass flow characteristics of the original and the optimized seal showed that the optimized seal provides reduced mass flow over a wide range of pressure ratios. The results obtained lead to the conclusion about geometric parameters influence on the mass flow and the effectiveness of labyrinth seals optimization to reduce air leaks.