bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-Magnetic Solid Body in Ferrofluid Containers: Wall Effects
Authors: Ivanov A S , Khokhryakova C A
Published: June 2021

Experimental and numerical investigations of a magnetic ponderomotive force acting on non-magnetic body immersed in ferrofluid were carried out. The study was performed on a nonmagnetic sphere in a cylindrical container filled with the magnetic fluid and magnetized by a uniform magnetic field. The symmetry of the experimental setup allowed the simplification of the problem: 2D axisymmetric numerical simulation corresponded to the 1D experimental measurements. The magnetic ponderomotive force turned out to be non-monotonic: it has two extrema and one or three zero values depending on the geometrical parameters of the container and magnitude of the applied field intensity. It was shown that wall effects are crucial for this problem, because the ponderomotive force in the vicinity of the container’s bottom (or top) may change its sign (direction). This behaviour can be described only in the framework of the inductive approach, which takes into account all demagnetizing fields generated by the ferrofluid container. On the contrary, the simplified non-inductive approach is unable to explain the magnetic force behaviour, especially the wall effects.
Nonlocal FEM Simulations of Ductile Damage with Regularized Crack Path Predictions
Authors: Klyuchancev V S , Shutov A V
Published: June 2021

Constitutive equations of finite strain elasto-plasticity are coupled to continuum damage mechanics to simulate the initiation and propagation of cracks in ductile materials. The diffuse deterioration of material’s strength is modelled using porosity as a damage parameter. We show that the local damage model yields simulation results, pathologically dependent on the FEM mesh upon mesh refinement: (i) the structural behaviour becomes unrealistically brittle; (ii) the FEM mesh determines the crack path. To solve these problems, an integral-based approach to nonlocal damage is implemented. It enables physically sound results by introducing the linear size of the microstructure into the model’s formulation. To prevent the effect of unrealistic diffusion of damage, the averaging operator is applied not to the porosity, but to its dual parameter, material’s continuity. Solutions of test problems for crack propagation in a compact tension specimen are presented. The convergence of FEM solutions is demonstrated for different slopes of the mesh with fine and coarse discretizations.
An Integral of the Two-Dimensional Stationary Viscous Fluid Flow Equations
Authors: Knyazev D V
Published: June 2021

This study demonstrates that the equations for a two-dimensional steady flow of a viscous fluid contain an integral of motion, i.e., they have some function whose gradient is zero in the solutions of hydrodynamic equations A system of partial differential equations has been derived to calculate this function. It has been established that, at a certain integral of motion, the calculation of hydrodynamic fields is reduced to the solution of a system consisting of three first-order partial differential equations with a characteristic manifold.
Surface Properties of Pulmonary Surfactant Sampled by Bronchoalveolar Lavage and by Electrostatic Exhaled Aerosol Trapping
Authors: Mizev A , Shmyrov A , Pshenichnikova-Peleneva I , Shmyrova A , Mizeva I
Published: June 2021

The development of efficient methods for non-invasive collection of alveolar lining fluid (ALF) samples containing pulmonary surfactant (PS) components and the study of the surface activity of the obtained native material is relevant for the diagnosis of inflammatory pneumopathies of the lungs. The paper presents an electrostatic aerosol trapping (ESAT) mobile complex for capturing droplets of ALF contained in an exhaled air. Passing the exhaled air through the corona discharge area results in the aerosol droplets charging and their further transferring by electrostatic force into a water surface, where they accumulate forming an adsorbed layer. Additionally, ALF samples were collected using a bronchoalveolar lavage (BAL). The surface properties of the PS obtained by both methods have been examined using the capillary wave method, which was previously modified by the authors specifically for biomedical applications. Significant difference was found in the results obtained with ESAT and BAL in the group of healthy subjects, which can be explained by different origin of the samples obtained by these techniques. Furthermore, significant difference in surface properties was established in the samples collected from healthy volunteers and patient with disseminated tuberculosis, while we did not find significant differences in the limited inflammatory process. The results presented in the paper demonstrate high potential of the proposed non-invasive technique for clinical usage.
Experimental Study of Fatigue Damage Accumulation in Laminated Carbon Reinforced Fiber Plastics
Authors: Nihamkin Mikhail Sh , Solomonov Danil G , Voronkov Andrey A
Published: June 2021

It is necessary to achieve high fatigue strength in order to apply carbon reinforced fiber plastics (CRFP) for critical elements subjected to vibration. Gradual accumulation of fatigue damage is accompanied by changes in the material stiffness and natural frequencies. The purpose of this work is to found experimental data on the change of the elastic characteristics of layered CRFP as fatigue damage accumulates. The object of the study is standard samples made of unidirectional carbon/epoxy fiber with different layering schemes. The samples were subjected to fatigue tests under cyclic tension with constant amplitude. The test of each sample was stopped several times at different loading stages to execute experimental modal analysis and non-destructive inspection of the appeared defects. The found natural frequencies were used to solve the inverse problem of identifying the elastic parameters of the laminate monolayer: two Young’s modulus, shear modulus and Poisson’s ratio. As a result, the dependences of these parameters on the relative fatigue life were obtained. These dependences, together with the results of non-destructive testing, can be used to describe the process of fatigue damage accumulation and for the subsequent development of methods for the fatigue life prediction.
Mathematical Modeling of Fatigue Fracture at High-Frequency Bending Vibrations
Authors: Nikitin I S , Burago N G , Nikitin A D , Stratula B A
Published: June 2021

A two-criterion kinetic damage model is proposed to describe the development of the fatigue fracture process under cyclic loading. On this basis, a procedure is proposed for calculating the coefficients of the kinetic equation for various modes of fatigue fracture from low-cycle to very-high-cycle fatigue. A uniform numerical method has been developed based on an implicit approximation of the differential equation for damage. This method makes it possible to carry out an end-to-end calculation of the evolution of crack-like zones of fatigue fracture in the material without considering cracks in their classical sense, as well as to estimate the durability of samples from the first nucleation to macrofracture. Calculations were made of the fatigue fracture of specimens under long-term cyclic loading according to the three-point bending scheme with the development of crack-like fracture zones in the modes from HCF to VHCF. Comparison of numerical and experimental results for specimens of titanium alloys is carried out.
Experimental Study of the Strength Characteristics of a Modified Polymer Base Material for Use in Orthopedic Dentistry
Authors: Shuliatnikova O , Rogozhnikov G , Porozova S , Rogozhnikov A
Published: June 2021

Acquired defects of the maxillofacial region require orthopedic treatment. When choosing a structural material for the manufacture of a jaw prosthesis, it is necessary to provide for functional loads on the prosthesis during operation. Defects in the jaw bones require a structural material with high strength characteristics. The article deals with the method of increasing the strength of polyamide dental material with nanoscale titanium dioxide. Objective: to improve the strength characteristics of orthopedic structures made of polyamide. The study of the polyamide material was carried out on control and experimental samples, in which a modifying component was introduced by the method of dispersion reinforcement-nanoscale titanium dioxide in an amount of up to 1 wt.%. The three-point bending strength (σmax, MPa) and Young’s modulus (E, MPa) were experimentally studied. These criteria are indicative when assessing the strength of the basic structural materials from which removable dentures are made. These parameters take into account both vertical and horizontal functional loads, similar to the forces that arise when using removable dentures. The results of the study showed an increase in the maximum voltage by 8.4%, and the Jung module by 7.2% in samples with nanoscale titanium dioxide introduced into their composition to 1 wt. %. This study is of practical importance for orthopedic dentistry in cases where it is necessary to strengthen the structural base material in the manufacture of jaw prostheses for patients with acquired defects of the jaw bones, which reduces the risk of fracture of the base structures under the influence of functional loads.
Experimental Study of Dehumidified Air Convection by Holographic and Thermocouple Methods
Authors: Somov S A , Ivanov A S
Published: June 2021

Thermal convection of dehumidified air is studied experimentally under conditions close to normal (atmospheric pressure ≍ 740 mm Hg, temperature range T = 0…50 C). The study is based on fundamental experiment, which is focused on the physical aspects of thermoconcentration convection in fluids, undergoing first-order phase transitions of the “gas-liquid” type. The peculiar features of convection, caused by concentration changes of water vapor (as a result of its evaporation or condensation), are discussed in terms of dimensionless parameters. The couple of standard complementary experimental methods are used: holographic interferometry for visualization of convective flows and thermocouple method for heat flux measurements. Test experiments demonstrate and approve the design characteristics of the setup. The observations of convective flows in dehumidified air are demonstrated. Experimental setup is described in all details, including the original design of the cold heat exchanger (resembling a heat tube), proposed for next experiments with humid air.
Deformation of a sphere made of magnetoactive elastomer under a strong uniform magnetic field
Authors: Stolbov O. V. , Raikher Yu. L.
Published: June 2021

Magnetostriction effect of a spherical sample of a magnetoactive elastomer (MAE) is analyzed. In comparison with the preceding study, the consideration is done on a more realistic basis: taking into account saturation of the MAE magnetization in contrast to the former model where the magnetization was supposed to be linear whatever the field strength. This more thorough investigation has revealed that the striction-induced elongation effect, depending on the material parameters, may occur in two forms. One scenario manifests itself as tapering of the polar zones of the former sphere, where ‘beaks’ are formed, so that the shape of the object drastically deviates from a spheroidal one. The mechanism the underlies the occurrence of beaks is the surface instability of a magnetizable elastic continuum, and the beak nucleation follows the second-order transition pattern; the resulting overall elongation of the body does not display any hysteresis. Another scenario—it is related to MAEs with higher magnetic properties and softer matrices—implies that the beak formation happens simultaneously with a jump-like overall elongation of the former sphere, and this transformation resembles the first-order transition pattern. Upon assessing the chances to observe the predicted effects on the samples of now existing MAEs, one comes to a conclusion that the second scenario is hardly possible, whereas the first one, i.e., beak formation without hysteretic stretching, is much more realizable.
Application of Electroimpedance Spirometry for Clinical Assessment of Respiratory Function Indices
Authors: Zuev A L , Shakirov N N , Sudakov A I , Ju Mishlanov V
Published: June 2021

A practical method of studying the dynamics of respiratory function associated with the registration of the electrical impedance of conductive biological fluids exhaled by the patient is described. In the model measuring cell, the physical causes and relationships in the conductivity of the air flow, saturated with an electrolytic fluid aerosol created by an ultrasonic nebulizer have been investigated experimentally. The design of a new electrical impedance spirometer in the form of a mouthpiece with electrical sensors, filled with a porous medium impregnated with electrolyte, through which the patient breathes, is developed and tested. To register fluctuations in the magnitude of the impedance modulus, an original hardware and software complex is used, made on the basis of a high-speed analog-to-digital converter. Based on electrical impedance analysis data, the methods are proposed for quantitative assessment of the basic spirometric medical indicators characterizing the state and functioning of the patient’s breathing apparatus, such as respiration rate, entry and expiration rate, exhaled air volume, amount and concentration of exhaled lung fluid.
Impact the parameters of metal-inducer system on its electromagnetic measurands
Authors: Okatev R. , Kolesnichenko I.
Published: June 2021

In this work, we propose the finite-element-based mathematical model of the metal-inducer system. This system consists of a coil with put-on C-shaped ferromagnets. We study how the measurands of the inducer, such as the coil voltage and the uncompensated force acting on metal, depend on the system parameters. We variate the geometry of the system to estimate the boundary effect impact. Also, we study how the coil voltage depends on the ferromagnets’ spacing and their number. The inhomogeneity of electric conductivity is modeled via holes in the metal volume. To estimate their impact, we defined the dependences of the measurands on the number and the size of inhomogeneities.
Production of TiC – Co and TiC – NiCr Composite Powders and Study of Their Interaction with a Target under Cold Spray Conditions
Authors: Kosarev V F , Klinkov S V , Chesnokov A E , Smirnov A V , Shikalov V S
Published: June 2021

In the first part of the paper, the effect of mechanical treatment of particles of reacting Ti + C + Me (Me = NiCr or Co) mixtures on the process of self-propagating high-temperature synthesis (SHS) is investigated. It is shown that as a result of SH-synthesis in the free burning mode, a metal-ceramic sinter of high porosity is formed, which is easily destroyed by mechanical action. An increase in the volume fraction of the metal binder (NiCr or Co) leads to a redistribution of the sizes of carbides towards smaller values.

In the second part of the paper, the results of cold spraying nickel-chromium alloy particles and cermet particles of the TiC – NiCr composition on an aluminum substrate are presented. Produced NiCr coatings have a high porosity (up to 10 %) and a layered structure with clearly defined contours of individual deformed particles (splats). Due to the high hardness and low plasticity of metal – ceramic particles of the TiC – NiCr composition, during their interaction with the surface of aluminum substrate, continuous coating cannot be produced, only individual adhered particles are observed. With prolonged exposure to the flow of such particles, erosion of the substrate takes place.
A Study of Music Data Influence Under Machine Learning and Directed Network
Authors: Wang Chen , Li Mingyu , Cai Yuhuan
Published: June 2021

As we all know, the twentieth century has undergone earth-shaking changes, whether it is historical background, philosophical and aesthetic thoughts, political situation, military atmosphere, science and technology, etc. This situation also provides a good development environment for music. Based on this background, we study the relevant music data since the 20th century; build relevant models to understand and measure the influence, evolution and development of music. In order to build a bridge between music data, the musicians are classified as followers and influencers and the relationship between them is explored, and then the data is established by directed network link. Considering the irreversibility and difference of the influence between followers and influencers, this paper, on the basis of the traditional directed network link, fully considers the structural characteristics of the directed network, establishes a linear programming model, constructs a similar matrix by solving the optimal solution of the contribution matrix, and constructs a directed network linear programming index; Finally, the influence between follower and influence is reflected by the size of contribution value.
An Improved JITL Method for Soft Sensing of Multimodal Industrial Processes for Search Efficiency
Authors: Chen Yushan , Lin Yuan , Zheng Tianyu
Published: June 2021

In the industrial process, due to product change, working condition switch, or controller adjustment, process data often presents multimodal characteristics. Data-driven approaches are often based on single-modal assumptions, which may fail to describe process characteristics. The traditional just-in-time learning (JITL) method can continuously update the model to describe the multimodal data, but it takes much time and cannot meet the real-time requirements. In this paper, an improved JITL method is proposed to find similar samples quickly. The new samples are divided into the main category first, and then find the similar samples to improve the search efficiency. The effectiveness of the method is proved by a case of an industrial soft sensor case combined with partial least squares (PLS). Compared with the basic JITL, the root mean square error (RMSE) of the proposed method is reduced by 0.09, and the running speed is increased by 8.8 times.
An Image Recognition Algorithm Based on Big Data Technology
Authors: Ran Yijiang , Feng Zejing
Published: June 2021

In order to solve the problem of poor accuracy in small target recognition, a target detection algorithm guided by double attention model is proposed. Based on the implementation principle of the single-stage detection algorithm, this method introduces two attention models to improve the detection performance, especially for small target objects. Firstly, a multi-scale feature cascade attention module is introduced into the convolution neural network to pay attention to different regions in the feature map of the original convolution neural network, so as to reduce the background of the feature graph and the interference of negative sample information. especially in the shallow feature map, we can pay attention to small target objects effectively. In addition, the dense connection alleviates the problem of gradient disappearance in the process of network back propagation. Secondly, the significant channel self-attention module is introduced into the fused features to distinguish the different channels of the feature map and screen out the useful channel information to make the features to be detected more representative. The proposed method is tested on the target detection benchmark data set COCO to verify the effectiveness and advanced nature of the proposed method.
Surface hardening of steel 20H13 for friction pair with carbon plastic by ion-plasma Ti-Al-N, Ti-Al-Ni-N coatings deposition
Authors: Belov D S , Blinkov I V , Anisimov A V , Chernogor A V , Lishevich I V , Sobolev M Yu , Shibakov I A
Published: June 2021

The paper presents the results of comparative studies of Ti-Al-N and Ti-Al-N-Ni coatings deposited on 20H13 (DIN 1.4021) steel, used as bearings in shipbuilding and working in a friction pair with UGET (carbon epoxy fabric) carbon plastic. It was found that the addition of nickel into the coatings composition significantly improves the corrosion resistance of the coatings in sea water. The study of tribological characteristics indicates an increased wear of steel and Ti-Al-N coating, determined by the corrosion destruction of the samples, which accompanies the process of friction
Thermodynamic modeling of Ni-Cr-B-C-Si system in “air+propane” atmosphere
Authors: Ilinykh N I , Krivorogova A S , Gelchinsky B R , Ilinykh S A , Leontiev L I
Published: June 2021

In this paper, thermodynamic modeling of a powder self-fluxing material PGSR-2 based on nickel (wt. %): Ni-79.3, C-0.5, Cr-15, Si-3.2, B–2 was carried out. The simulation was performed in the temperature range of 300-6000 K in the atmosphere of “92 vol. % air + 8 vol. % propane” at a total pressure of P = 105 Pa. The temperature dependences of the equilibrium composition of the condensed and gas phases formed during heating are calculated.
In vitro study of the antibacterial properties of amorphous copper-doped carbon coatings
Authors: Sergeev G K , Sergeev K S , Samikova V N , Altfaumi S , Rubshtein A P , Vladimirov A B
Published: June 2021

A deposition technology of amorphous carbon coating (a-C), doped with copper (C-$$$Cu), has been developed. The C-Cu coating deposition was performed with the simultaneous operation of arc- and pulse-arc sources with copper and graphite cathodes, respectively. There was studied the antibacterial activity of the a-C and C-Cu against E. coli, S. aureus and P. aeruginosa. The copper-doped coating has bactericidal activity against P. aeruginosa. The number of bacterial colonies is five times lower in compare with a-C and Ti.
Implementation Effect of Targeted Poverty Alleviation in City D Measured by the Satisfaction Degrees of Poverty-stricken Households
Authors: Xiaoyan Du , Fumin Zhang
Published: June 2021

This paper quantifies the implementation effect of targeted poverty alleviation in city D based on survey data using analytic hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE). On the basis of defining the concepts of poverty, targeted poverty alleviation, and implementation effect, it introduces four criterion layers (satisfaction degree with targeted identification, satisfaction degree with targeted assistance, satisfaction degree with targeted poverty relief, and satisfaction degree with management of special fiscal funds for poverty alleviation), and adopts pairwise matrices to perform consistency check, thus analyzing the implementation effect of targeted poverty alleviation and the satisfaction degrees of poverty-stricken households in city D. In the end, it proposes targeted measures and suggestions.
Research on the Application of Big Data Technology in Network Security Analysis
Authors: Ning Yingying
Published: June 2021

China’s information technology development and scientific and technological undertakings have entered a period of rapid development, and big data technology, as an important technical support and management tool, plays an increasingly prominent role in ensuring network security analysis. Faced with various deficiencies in network security analysis and data management at this stage, we must optimize network security analysis by applying network security data analysis platforms and big data core technologies. In particular, the multi-functional file management and technical integration in the data analysis process are conducive to the continuous improvement of file management, statistical efficiency and platform quality. Through scientific distribution and optimization of structure distribution, the efficiency of data and information storage management can be improved, and network security prevention capabilities can be improved to a large extent. This article first briefly explains the importance and necessity of big data technology, and analyzes the status quo of the problems in the process of data collection and analysis. The author further proposed the strategy of optimizing big data technology and promoting file management management to effectively guarantee the development quality and economic benefits of online statistical data and offline analysis technology.
Analysis on the Development of Potential Disciplines in Universities Based on Incites and ESI---Taking University of Jinan as an example
Authors: Tianmei Guo , Hua Shao , Xuehong Zhao , Chuanli Du
Published: June 2021

We provide objective data support for the discipline planning and discipline construction of University of Jinan, and speed up the entry of potential disciplines into advantageous disciplines, increase the influence of disciplines, and improve the quality of higher education. The threshold value relative gap method is used to calculate the potential value of potential disciplines, and the most potential disciplines of biology and biochemistry are selected. We analyze the trends of biology and biochemistry from the output of papers and the total citation frequency of papers, the distribution of cooperative institutions, and the situation of publishing journals. The total number of scientific research papers in biology and biochemistry is insufficient, and the total citation frequency of these papers has dropped significantly. There are fewer international and domestic cooperation agencies and the coverage of journals is narrow.
Whether Executive Incentives Restrain Corporate Violations: An Empirical Study Based on the Statistical Data of Listed Companies
Authors: Dong Li , Liu Quanhong
Published: June 2021

Corporate violation of listed company has always been one of the researches focuses in the field of corporate governance, and executive incentives are considered to be an effective way to solve the principal-agent problem. This paper uses 454 companies that were publicized in the A-share market due to corporate violation in 2013-2017 as the research objects to explore the impact of salary incentives and equity incentives on listed companies’ violations, and explore the adjustment of the above-mentioned influence mechanism by the gender and age of executives’ effect. The study found that the compensation and equity incentives provided by shareholders of listed companies to executives can effectively suppress the violations of listed companies. Female executives can strengthen the inhibitory effect more than men, and the older the executives, the more the inhibitory effect can be strengthened.
Hyperspectral image classification based on multiscale convolutional network
Authors: Ju Yi
Published: June 2021

Hyperspectral Image (HSI) classification is an important task in the field of Hyperspectral Image processing. However, the existing classification methods unable to solve the problems caused by hyperspectral image information redundancy, insufficient image feature utilization and Hughes phenomenon. Aiming at these three problems, a hyperspectral image classification algorithm based on deep learning is proposed. The Multiscale Convolutional Neural Network (MCNN) was used to excavate deep features and realize the learning of multiscale features. Then, the features of different scales were fused and classified. The results show that the proposed algorithm has higher classification accuracy than the traditional ones. Also, it has strong generalization ability and robustness. The effectiveness and feasibility of the proposed algorithm are fully verified.
A Method of Blood Vessel Segmentation in Fundus Images Based on Image Enhancement
Authors: Tao Juliang
Published: June 2021

The changes of retinal vessel width are the key steps in the accurate diagnosis, early treatment and surgical planning of ocular diseases. The segmentation of retinal vessel is the basis of computer-aided diagnosis and large-scale disease screening. In this paper, we propose an algorithm for segmentation of fundus image based on image enhancement. At first, the ocular fundus image is enhanced by Laplacian pyramid, and the enhanced image vessel is more obvious than the background. Then, an improved matching filter algorithm is used to segment the ocular fundus image vessel. Experimental results show that the proposed method is more accurate than the traditional segmentation method. And it has strong robustness to the fundus images under different illumination conditions.
The application of discrete mathematics to microeconomics
Authors: Tao Lina , Cheng Jiaxing
Published: June 2021

Mathematical logic is one of the two cornerstones of discrete mathematics course, which uses mathematical methods to study the relationship between the premise and conclusion in reasoning. Microeconomics is the study of individual economic units, how market mechanisms work and function when resources are scarce, and ways to improve their functioning. Game logic is a new direction in the field of logic game theory is mainly applied to behavioural theory in microeconomics. This paper studies the combination of logic and game theory from the propositional logic in mathematical logic.
Kernel-lasso feature expansion method: boosting the prediction ability of machine learning in heart attack
Authors: Dai Zongrui , Jiayi Li , Gong Taowen , Wang Chenfei
Published: June 2021

Heart attack needs to cause a high degree in modern society, which is now at the top of the list of most common diseases. One-third of all deaths in the world are caused by heart disease, and in our country, hundreds of thousands of people die of heart disease every year. If people can predict heart attack at an early period, they may prevent and cure the potential risk. Therefore, one novel and efficient prediction model is needed. Based on machine learning, we design one novel method in feature selection called kernel-lasso feature expansion to increase the prediction ability. This method considers the potential influence by the curse of dimension and lack of features, which can increase the dimension of the existed data and select the effective features by lasso regression. Compared with other feature selection methods such as Lasso and step regression, the novel method increases the predicted ability of gradient boosting machine, DNN, and SVM models, while SVM with kernel-lasso feature expansion achieves the best performances in Accuracy (0.84(%95Cl:0.78-0.89)).
Analyzing the current status of global 5G research from the perspective of bibliometrics
Authors: Mao Yuanyuan
Published: June 2021

In order to fully understand the current research status in the field of 5G technology, using 5G documents included in the WOS?Derwent Innovations Index as the data source, this article conducts a bibliometric analysis of “5G technology” from multiple dimensions such as the number of publications, countries, institutions, and patents. Through the CiteSpace software, the scientific knowledge map in the 5G field is drawn, and the research overview in the 5G field is obtained, scholars in this field can make theoretical references in further research.
A new method for judging the stability and boundedness of continuous-time fractional positive systems
Authors: Yang Lijuan
Published: June 2021

By decomposing the state matrix into a symmetric part and an antisymmetric part, this paper investigates the stability of continuous-time fractional positive systems, and a sufficient and necessary condition for continuous-time fractional positive systems to be bounded in a given interval is obtained. The results show that when the system corresponding to its symmetric part is asymptotically stable, continuous-time fractional positive systems is also asymptotically stable.
Research on multi feature fusion perception technology of mine fire based on inspection robot
Authors: Miao Kebin , Ma Jian , Li Zefang , Zhao Yunlong , Zhu Wenshuo
Published: June 2021

In order to improve the real-time and accuracy of mine fire identification, based on the summary of the existing fire monitoring methods, a mine fire early warning model based on patrol robot and multi-sensor and image recognition is proposed. The video image is obtained by using the high-definition camera of inspection robot, and the flame suspected area of video image is obtained by combining frame difference and background difference after filtering. The improved three scale analytic hierarchy process is used to fuse the circularity feature, sharp angle feature, centroid movement feature, color feature and area growth feature of the flame suspected area image to obtain the flame result. The three-frame difference method is used to binarize the smoke video image, and the smoke texture feature, smoke motion feature and smoke color feature are extracted to recognize the smoke image. The improved three-scale analytic hierarchy process (AHP) is used to fuse and judge the smoke in the combination of infrared thermal imager temperature measurement and smoke sensor. Inspection robot uses unified detection standards and intelligent analysis technology to sense mine smoke and flame. This method can improve the real-time, accuracy and robustness of mine fire perception.
An Empirical Analysis of the Bidirectional Dynamic Effect between Financial Competition and Industrial Agglomeration
Authors: Wang Zhengyu , Pang Ran , Cai Defa
Published: June 2021

This paper uses the data of 30 provincial-level panel in China to establish a dynamic panel simultaneous equations model. The system generalized moment estimation (sysgmm) and three-stage least squares (3SLS) are used to estimate and test the robustness of the model, respectively, to study the relationship between financial competition and industrial agglomeration. The results show that: (1) there is a bidirectional causal relationship between financial competition and industrial agglomeration. Financial competition through preferential policies to encourage technology research and development, resulting in technological innovation spillover effect to attract industrial agglomeration, but the effect is not good, and industrial agglomeration will also encourage finance to increase the competitiveness; (2) the bidirectional effect has time lag, the early financial competition and industrial agglomeration In order to have an effect in this period. All of conclusions above have important implications for changing the mode of financial competition and improving the quality of industrial agglomeration.
Research on Embedded Navigation System of Agricultural Robot Based on ARM
Authors: Wang XiaoJian , Hou Xujie , Niu Wenhuan , Jiang Shaoyan
Published: June 2021

This paper takes agricultural robot as the research object, combines machine vision and embedded technology, proposes an embedded agricultural robot image processing and path navigation algorithm based on machine vision, and successfully transplants the image processing and path navigation algorithm to the embedded environment based on ARM9.
User Experience of Loading Design: the Influence of Different Presentation Duration and Type on Time Perception
Authors: Hou Danni , Yao Kang
Published: June 2021

This study simulates the situation that users are required to wait when they encounter a buffer when watching online video, and investigates the influence of the duration and type of loading on time perception. The task was to estimate the perceived loading time. Results (1) the accuracy of time perception decreased with the time of loading. (2) the type of loading is related to time perception. The larger the amount of information contained in loading, the shorter the time perception of viewing video. (3) there is interaction between the duration of loading presentation and the type of loading. The results show that the amount of information and waiting time are related to time perception.
Study on the Construction of Curriculum System for the Integration of Environmental Design Courses and Certificates in Colleges Based on Statistical Analysis
Authors: Guo Lingling , Zhang Lipeng
Published: June 2021

With the start of the pilot work of the 1 + X certificate system in China, the education department began to encourage college students to strive for the corresponding vocational skill level certificate on the basis of obtaining the academic certificate, so as to improve the employment situation and alleviate the current social employment difficulties. In this paper, the environmental design professional courses in Colleges and universities as an example, in-depth analysis of the shortcomings of the current single teaching environmental design professional course system, through the statistical analysis of the questionnaire of college students and enterprises, the feasibility of realizing the integration of environmental design professional teaching course certificate under the experimental conditions of “1 + X” certificate system in Colleges and universities is studied, and the corresponding curriculum system is constructed. The statistical results show that when the curriculum system of environmental design is adopted, the satisfaction of students and enterprises has increased. The results show that the integration of academic education and vocational skills training can be achieved by setting up the course of “course certificate integration”, which is helpful to cultivate a large number of students who meet the needs of enterprises and improve the employment rate of college students
An elevator passenger behavior recognition method based on two-stream convolution neural network
Authors: Lan Shengnan , Jiang Saihua , Li Gang
Published: June 2021

In order to reduce elevator accidents caused by passengers’ incorrect use, a method for elevator passenger dangerous behaviour recognition based on two-stream convolutional neural network is proposed after analysing existing elevator passenger behavior recognition methods. A two-stream convolution neural network model framework and its parameters for elevator passenger behavior recognition are also given. Herein, the appearance features of human behavior are extracted from space domain, and the motion features of human behavior are extracted from time domain. Finally, the softmax outputs of the two-stream are merged with the liner weighting to realize human behavior recognition. The model is trained and evaluated on the video dataset of elevator passenger behavior. The results show that this method can be used to identify the unsafe behavior of elevator passengers, and the average recognition rate is 96.87%.
Method for detecting surface defects of runner blades of large hydraulic turbines based on improved real-time lightweight network
Authors: Liu Cheng , Su XinYi , Wu Jialing , Zhou Qun , Li Tao , Tian Tang , Li XianYong , Hu GuiChuan
Published: June 2021

Cavitation erosion, wears and cracks caused by residual thermal stress occur during the operation of hydropower units. It is a key scientific problem that needs to be solved urgently to detect defects in the foundation pit of hydropower units. In this paper, a mobile robot is used to obtain the surface image of the over-current parts of hydropower units, and deep learning algorithm is used to detect defects. In order to detect blade surface defects more safely, reliably, efficiently and quickly, this paper proposes an improved real-time lightweight convolutional neural network MobileNetv3-YOLOv4-Lite, which is suitable for portable embedded devices. In this paper, MobileNetv3 is selected to replace CSPDarkNet53 as the new backbone extraction network, and all standard convolutions are replaced by depth separable convolutions. Compared with CSPDarkNet53, MobileNetv3 only needs 37.35MB in weight, which is 206.94MB lower. It shows that the network proposed in this paper has the advantage of low memory and can run on CPU. The defect detection accuracy of MobileNetv3-YOLOv4-Lite can reach 97.48%, and the GPU can process 3024x4023 images, which can process 44 images in one second. The standard convolution of the enhanced feature extraction layer network is replaced by the depth separable convolution, and the parameter quantity is reduced by 29.33%. Therefore, it can be considered that the real-time lightweight convolutional neural network MobileNetv3-YOLOv4-lite proposed in this paper can detect the surface defects of turbine blades well.
Detecting and Classifying Self-Admitted of Technical Debt with CNN-BiLSTM
Authors: Zhu Kuiyu , Yin Ming , Li Yizhen
Published: June 2021

Technical debt expresses the use of non-optimal solutions for short-term gains. Self-admitted technical debt is a technical debt that is deliberately introduced and recognized by developers in source code comments, including design debt, requirement debt, and defect debt, etc. Currently, many methods are proposed to detect SATD. However, these methods are limited to the identification of SATD or non-SATD. In this paper, we propose a CNN-BiLSTM method to detect and classify SATD. Through our cross-project experiments on 10 projects, it is shown that our method can not only effectively detect SATD, but also classify design debt, requirement debt, and defect debt in SATD.
A study on optimal dispatch of meical resources under the situation of COVID-19
Authors: Yang Yingrui
Published: June 2021

In order to improve the efficiency of production, transportation, storage and use of medical resources under COVID-19 pandemic, we propose a simplified model for medical resources supply chain management by mathematical programming. Based on the reserve and demand of medical resources in a given area, the proposed model provides daily real-time transportation decisions and expansion decisions of hospitals, factories and warehouses under epidemic situation by analysing factors such as different regions, duration, factory capacity, warehouse reserves, hospital demand, transportation and expansion costs of factories, warehouses and hospitals. The promo package of Python language is used to formulate a mixed integer linear programming model. In this model, under the conditions of meeting the demand of medical resources in the case of slow development and sudden outbreak of epidemic situation, a commercial solver, CPLEX, is able to provide the solution for each situation with the lowest supply cost within one second CPU time. This model provides a feasible scheme for further solving the complicated forecasting and planning of medical resources dispatch under the situation of pneumonia in COVID-19.
Analysis of an epidemic model with latent infection
Authors: Liu Wenjuan , Chang Zaibin , Qiao Yaqin
Published: June 2021

An infectious disease model with latent infection is studied, and the basic reproductio n number of the model is obtained When the basic reproducing number is less than 1, the mode l has only one disease-free equilibrium. When the basic reproducing number is greater than 1, t he disease-free equilibrium is unstable. The model also has a unique positive equilibrium. The global asymptotic stability of the two equilibria is analyzed by linearization method, Liapunov function method and geometric method.
Research on the impact of 5G technology on teaching behavior
Authors: Xue Jianting , Mao Yuanyuan
Published: June 2021

Affected by the COVID-19, the opening of higher education institutions in China has been postponed, and the policy of “suspending classes without stopping” has become a litmus test for emergency response to the epidemic and for education informationization. Under this opportunity, the online teaching model has risen rapidly and has become a hot spot for teaching reform. This article explains the development process from traditional teaching to smart teaching, and the shortcomings of online teaching at this stage. On this basis, with the new generation of communication technology 5G as the background of the times, the future teaching is prospected from the aspects of AI teaching, holographic interactive classroom, and virtual technology teaching.
Mountaintop mining legacies constrain ecological, hydrological and biogeochemical recovery trajectories
Authors: Ross Matthew R V , Nippgen Fabian , McGlynn Brian L , Thomas Christian J , Brooks Alexander C , Shriver Robert K , Moore Eric M , Bernhardt Emily S
Published: June 2021

Mountaintop mining, like all forms of surface mining, fundamentally alters the landscape to extract resources that lie 10–100 ms below the land surface. Despite these deep, critical zone alterations, post-mining landscapes are required by United States law to be restored to ecosystems of equal or greater value than the ones they replace. Yet, remote sensing of vegetation across more than 1000 km2 of reclaimed surface mines in WV, USA reveals little evidence that these habitats are returning to the diverse Appalachian forests that were removed by mining. Instead, even decades after reclamation, mined landscapes are dominated by shorter and sparser trees. Based on detailed field studies and literature synthesis, we suggest that part of these widespread failures in re-establishing native forest result from the fundamental changes in critical zone processes on the post-mining landscape. Former surface mines have substantially altered topography, hydrology and chemistry. In these post-mining, synthetic landscapes, water moves more slowly through piles of exploded bedrock, changing the system from one dominated by stormflow in unmined catchments, to one dominated by baseflow after mining. This slow-moving water, travelling through high surface-area debris and pyrite-rich bedrock, creates ideal conditions for highly elevated weathering in mines both old and new. These foundational changes to the critical zone set ecosystem recovery along a novel trajectory, in which the legacy of past disturbance is likely to constrain the establishment of native forest for many decades.
Study on Mechanical Properties of Concrete-Filled Aluminium Alloy Tube Column under Lateral Impact
Authors: Yantao Jiang , Peiding Wang , Chuanyun Xiong
Published: June 2021

Concrete-Filled Aluminium Alloy Tube (CFAAT) column may be damaged by lateral impact. Based on general finite element analysis software, the dynamic analysis and performance of lateral impact of CFAAT columns with different tube wall thickness are studied in this paper. The results show that when the outer diameter of the columns is constant, the impact resistance of the columns can be improved by increasing the thickness of the aluminium alloy (Al alloy) tube, and the reinforcement of the core concrete constraint by increasing the strength and thickness of the Al alloy tube is the main reason for the enhancement of the impact resistance.
Research on Foundation Pit Monitoring and Management System Based on BIM+GIS+IOT
Authors: Chuang Gu , Yiqun Chen , Zhongmou Chen , Peng Li
Published: June 2021

Since traditional foundation pit monitoring methods cannot meet the overall safety requirements of engineering, a foundation pit monitoring and management system based on BIM+GIS+IOT was proposed in this paper. BIM, GIS and Internet of Things were applied in the system. ESP32 chip and ESP-IDF framework were used to develop the IOT to complete the real-time collection and transmission of monitoring data, and the BIM and GIS model data is integrated and displayed by linking the information of the monitoring points and BIM model. The system then is used in the construction of a subway station foundation pit for environmental monitoring and early warning monitoring.
Elastoplastic analysis of Kunshan Xintiandi super high-rise office building under earthquake
Authors: Zhang Xiaomeng , Liu Ziao , Yang Xiao , Zhou Yilun , Ren Qingying , Liu Wenting
Published: June 2021

Kunshan Xintiandi Super Tall Building is 142 meters high, with 3 floors underground and 31 floors above ground. Its structural system is composed of concrete-filled steel tube frame and core tube. The elastoplastic time-history analysis of the building was carried out by using PKPM-SAWS to analyze the overall overall index of the whole structure under large earthquake, and the mechanical performance of the key components under large earthquake was analyzed, and the loss mechanism of the key components under large earthquake was obtained, so as to ensure the mechanical performance target of the super high-rise building under large earthquake are not bad.