bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computer-Based Testing Complex “Profvybir”: Occupational Guidance Diagnostics
Authors: Kravchenko Oksana , Shelenkova Nataliia , Mishchenko Maryna , Boichevska Ilona 
Published: March 2021

Abstract
The importance of occupational guidance for individuals has been highlighted in the article. Modern tasks and challenges of occupational guidance have been presented and conditions of a personality’s successful self-realization have also been analysed. The article deals with the application of modern methods and forms of occupational guidance for students. The authors present the results of approbation of the computer-based testing complex “ProfVybir”, performed during 2015-2019 for the diagnostics of occupational interests and inclinations. It is used as a separate information service for students of 8-11 grades. The complex was created in Centre of Psychological Diagnostics and Training Technologies “Insight” of Pavlo Tychyna Uman State Pedagogical University. During the mentioned period 780 students took part in occupational diagnostics. The following algorithm of work with the computer-based testing complex consisting of three blocks is presented. The article defines that the method of occupational guidance can be used to implement the policy of the Ministry of Education and Science in the development of occupational guidance, can be applied by a career advisor at school, while the computer-based testing complex may be an additional component of the occupational training program.
Are Open Textbooks Effective for Learning? Investigating the Issue of Human-computer Interaction in Pedagogical Design of Open Textbook Affordable for a Diversity of Learning Environments
Authors: Railean E A , Elci A , Ivanova M , Alias M , Bîrnaz N 
Published: March 2021

Abstract
This article discusses the impact of human-computer interaction in the pedagogical design of open textbooks affordable into a diversity of learning environments. An exploratory study is conducted, wherein an online questionnaire is administered to the second-year master’s degree students from the Faculty of Psychology and Educational Studies. The results show that students are aware of the importance of metacognition in developing effective learning strategies. Thus, they use metacognitive strategies when taking notes, doing reflections, and employing mnemonics to enhance understanding. However, despite the current practice of using open didactical materials, students feel that the open textbooks approach needs to be relooked and changed to be more effective; it could be equipped with appropriate learning tools to provide more opportunities for immediate feedback and collaborative assessment. Individualization and collaboration are the key factors in developing metacognitive experience. These findings indicate that students are cognizant of the important role of open textbooks in promoting learning.
Research on the Key Technology and System Architecture of Smart Research Travel in Novel Coronavirus Epidemic
Authors: Li Yanan , Bu Naipeng(Tom) , Kong Haiyan , Yin Zihan , Ji Xiuchao 
Published: March 2021

Abstract
In December 2019, China’s research travel market plummeted as a result of the novel coronavirus epidemic. In the context of a depressed research market in the Information Age, the concept of “Internet + research” emerged. First, according to symbiosis theory, the symbiotic units of smart research travel are determined. Then, based on a structural design of smart research travel data system, key technologies in big data, cloud computing, and Internet of Things are described in detail. Finally, based on the traditional browser/server architecture model of computers, a smart research travel system architecture suitable for the epidemic situation is constructed. The purpose of this study is to build a new ecology of research travel, optimize resource allocation, and promote the healthy, stable, and sustainable development of research travel in the country.
Optical Flow Monocular Visual-Inertial Odometry with Online Photometric Calibration
Authors: Liu Quanpan , Wang Zhengjie , Wang Huan 
Published: March 2021

Abstract
Kanade-Lucas-Tomasi (KLT) optical flow algorithm based on the brightness constancy assumption is widely used in visual simultaneous localization and mapping (SLAM) and visual odometry (VO). However, the automatic adjustment of camera exposure time, the attenuation factor of sensor irradiance caused by vignetting, and the nonlinear camera response function will cause the same feature point to have different brightness values on different image frames, thus breaking this assumption. Hence, we propose a gain-adaptive KLT optical flow algorithm with online photometric calibration, and on this basis, design a monocular visual-inertial odometry which is insensitive to brightness changes. This method can calibrate the photometric parameters online in real time, meet the assumption of constant brightness in practical applications, and make the algorithm more robust and accurate in the case of dynamic changes in brightness. Experimental results on the TUM Mono and EuRoC datasets show that the proposed algorithm can reliably calibrate the photometric parameters of any video sequence and perform well in the environment with varying brightness.
Backstepping Sliding Mode Control of Uncertainty Flexible Joint Manipulator with Actuator Saturation
Authors: Chen Hongyu , Dong Xiucheng , Yang Yong , Liu Jiutai 
Published: March 2021

Abstract
To address the issue of the flexible joint (FJ) manipulator control with actuator saturation, singular perturbation method is adopted in this paper which decompose the manipulator model into two subsystems in terms of time scale transformation, the fast one represents flexibility and the slow one expresses rigidity, and the control law of which is designed respectively. For the fast subsystem, a velocity-difference-based feedback control is designed to lower the oscillation caused by joint flexibility, while for the slow subsystem, the control performance of the system is enhanced by a combination of a class of nonlinear integral sliding surface and backstepping global sliding mode. The radial basis function (RBF) neural networks are utilized to compensate the actuator saturation, the disturbance and the modeled uncertainties. Based on the Lyapunov theory, the tracking convergence of the closed-loop system is proved rigorously. The simulation result shows that the designed control law can maintain good rapidity and accuracy, moreover, chattering is eliminated.
Numerical Simulation of Energy Distribution of Turbulent Vortices in Atmosphere Effects on Aircraft Wake Vortices
Authors: Zhou Jinxin , Li Dong , Zhang Zeyu , Pan Weijun 
Published: March 2021

Abstract
The effect of energy distribution of turbulent vortices in atmosphere on the evolution of wake vortices is studied using the numerical simulation approach. Solution-Based Dynamic adaptive mesh method is applied to compute the wake vortex evolution using FLUENT. Two series of cases are designed to study the role of larger and small-scale vortices in the decay of wake vortex, respectively. The results show that energy distribution of different scale vortices has a significant effect on the onset time of vortex linking and the decay rate of wake vortices at the turbulent diffusion phase and fast decay phase.
Target Detection in NAO Robot Golfing
Authors: Su Erwei , Chen Long , Xu Yingli , Hu Bin 
Published: March 2021

Abstract
In robot golfing games, how to identify and track small balls is a critical step for scoring. Considering uneven illumination and intensity, irregular distribution, and blurred borders, an integrated detection method based on the random Hough transform and the Kalman filter is presented to improve the recognition accuracy, i.e., guaranteeing the detection accuracy and the stability in shooting. Experiment on the NAO robot is performed to show the effectiveness of the proposed detecting method. Both theoretical and experimental results suggest that the proposed recognition method can reduce the calculation time of the Hough transform and has a certain degree of robustness against uncertain environments.
The Influence of Grid Scale on the Tail Vortex Capture of Aircraft
Authors: Zhang Zeyu , Li Dong , Zhou Jinxin 
Published: March 2021

Abstract
The grid has appreciable impact on the simulation of the wake vortex. There is a big difference between the traditional aerodynamic estimation grid and the grid used for capture the main parameters of the trailing vortex in the far field. This paper compares the similarities and differences between these two kinds of grids. The main parameters of the coarse grid are quite different from those of the refined grid simulation in the far field. Sufficient quantity grids are required to simulate the flow field in the parameters of wake vortex prediction. Otherwise, it may draw the reverse conclusions with the physical truth.
Research on Vibration Excitation Estimation of Warship Propulsion Shafting Based on Waveguide Theory
Authors: Wu Haiping , Yang Lihua , Liu Libin 
Published: March 2021

Abstract
The propeller excitation can be estimated by measuring the vibration response of the shafting, but there are many difficulties, such as difficult to implement, difficult to determine the boundary conditions and so on. For this reason, the waveguide model of different shaft segments on the shafting and the waveguide transfer relationship between the connected shaft segments are established based on the waveguide theory, and the waveguide coefficient is estimated combined with the vibration response observation data. The estimation of longitudinal oil film stiffness of thrust bearing and admittance of thrust bearing housing and hull connection structure is avoided, and the method of propeller longitudinal excitation based on waveguide transfer relation is verified by a specific example. The results show that the method is feasible and effective, and provides a new method for accurately grasping the actual propeller excitation.
Study on the Spatial Relationship between Green Space and Surface Runoff in Suzhou City
Authors: Li Shuangqi , Ma Jianwu , Bi Yu 
Published: March 2021

Abstract
Green spaces are more than just part of the landscape; they are a powerful means of purifying and controlling surface runoff. In the context of urbanization, Suzhou faces serious problems of water pollution, urban waterlogging and water shortage, and the main cause of these problems is the inadequate treatment of surface runoff. As an advanced city in the country, Suzhou still faces water ecology problems caused by surface runoff under high green space conditions, which makes it urgent to analyze the relationship between the existing green space and surface runoff to further discover the problems and deficiencies of the existing green space in reducing surface runoff, thus providing a basis for future green space system planning.
CFD Numerical Modelling of Spontaneous Combustion of Loose Coal in High Caved Area of Underground Roadway
Authors: Yang Jianhui , Lei Yajun , Li Hucun , Yang Biao , Wang Zhenxing 
Published: March 2021

Abstract
Coal fires are serious health and safety hazards throughout the world. In underground, coal spontaneous combustion process often starts with the inside of coal, which makes it difficult to determine the ignition point. For example, the coal fire happened in high caved area of roadway is often hard to be noticed. Once the smoke appears, it has already been late to take control measures. In this paper, Simulation analysis of microcirculation flow field velocity distribution, temperature distribution and the possible distribution of the coal spontaneous combustion zone are preformed which could provide a good scientific and reasonable understanding of the fire risk due to microcirculation in loose coal in underground roadway.
Application of Water Quality Index in the Evaluation of an Abandoned Mine Areas of Xunwu, China
Authors: Yin Shiyun , Liu Zuwen , Yang Shi , Lin Yuan 
Published: March 2021

Abstract
Within the display think about, an surrendered ion-type rare soil mine contains a tremendous affect on the encompassing water environment contamination in Xunwu, Jiangxi Province, China. Since the usage of coordinates remediation innovation and extend in 2018, its natural quality has been enormously moved forward. In arrange to encourage assess the environmental remediation impact, a altered water quality index strategy (WQI) is proposed. Concurring to the grid method, 16 water quality examining focuses were set within the surrendered mine remediation extend, and 9 key assessment records such as NH4
+-N and heavy metals were chosen for principal component analysis (PCA) and factor analysis (FA), in arrange to comprehensively assess the worldly and spatial changes of different contamination variables within the deserted mine environmental remediation range. The results uncovered that the water quality of the surface water has been slowly progressed, and the generally water quality has been getting superior, among which the water quality in August is clearly superior than that in July, and the progressed water quality index is successful for the classification of water quality and the assessment of the transient and spatial changes of water quality within the remediation of surrendered mines.
Developing a Calcium Silicate Prefabricated Board Ventilated Wall for Building Energy Efficiency Retrofit in Hot-Humid Areas
Authors: Jin Xueli , Wang Junsong , Meng Qinglin 
Published: March 2021

Abstract
Ventilated wall is considered as an effective technique for building energy efficiency retrofit in hot-humid areas, and the heat exchange inside the ventilated layer blocks the heat gain into the wall. Most current researches focus on the performance assessment of the wall system but lack the optimize design of the external board. Here we demonstrated a new type of ventilated wall, using the calcium silicate material as the cladding panel for its excellent physical properties and easy installation and maintenance. In particular, the aluminum foil was attached to the interior side of the board to further lower the emissivity for achieving a better insulation effect. Based on the field experiment in summer days, the thermal performance of the new type of ventilation wall was obtained and further compared with the conventional wall. Moreover, the equivalent thermal resistance of this novel ventilated wall was also calculated. The results revealed that: the interior wall surface temperature and energy consumption of the new ventilated wall proposed was about 3-5°C and 39.2% lower than those of the conventional wall, respectively. The low emissivity significantly insulated the heat transfer inside the cavity. In parallel, the calculated equivalent thermal resistance of the ventilation wall (0.971m2⋅K/W) was also 2.07 higher than that of the conventional wall.
Pilot Study on Catalyzed Oxidation-Ceramic Membrane-High Pressure Reverse Osmosis for Desulfurization Wastewater Recovery
Authors: Wu Zhongjie , Hou Yaqin , Li Xinmei , Li Yanping , Cao Hongmei 
Published: March 2021

Abstract
With the increasing pressure of environmental protection, the zero-discharge project construction of power industry was speeding up. However, the unstable operation of equipment was often occured. With regard to this, the process of catalytic ozonation-ceramic membrane-high pressure reverse osmosis for desulfurization wastewater reuse was established in Huaneng Yunhe Power Plant. The amount of catalyst was firstly evaluated and the COD could be reduced from 264 ppm to 107 ppm. Even after the ozone catalytic oxidation process continuously operated for more than 20 days, the catalytic efficiency of the catalyst was still maintained at the original level. The operating pressure of the ceramic membrane was maintained at 0.17 MPa, and the wastewater recovery rate was more than 90 %. Moreover, the membrane flux of the ceramic membrane after backwashing could be recovered well. The desulfurization wastewater treated by catalytic ozonation process and ceramic membrane process was reused in the high pressure reverse osmosis unit. The operating pressure was maintained at 1.21 MPa and the water recovery could reach about 55%. The overall water recovery rate of ozonation ceramic membrane reverse osmosis process was 50%. The operation efficiency of each treatment unit was high and stable, and the performance recovery effect was excellent after the decline of membrane flux, which improved the operation stability of the whole treatment process.
Numerical Investigation on Flow Characteristics in the Horizontal Elbow Suction Pipe Connected to Sumps of Large-Scale Pumping Stations
Authors: Zhang Yetian , Feng Jianjun , Ge Zhenguo , Zhu Guojun , Wu Guangkuan 
Published: March 2021

Abstract
To know the flow characteristics in the horizontal elbow suction pipe connected to sumps of large-scale pumping stations, the distribution of air-entraining vortex and water velocity is studied using ANSYS CFX with considering the gravity. The Volume of Fluid (VOF) method is adopted to track the water level of the sump. The results show that a typical funnel-shaped continuous air-entraining vortex is observed via the air volume fraction. Its size gradually increases from the inlet to outlet of the suction pipe. The pressure changes linearly with the water depth under the effect of gravity whereas the velocity shows non-uniform distribution. The axial velocity distribution of the outlet is non-uniform in the radial direction, which is analogous to the velocity distribution. In addition, the centre wall of the suction pipe outlet may affect remarkably the velocity distribution.
The Influence of Anti-Cavitation Edge on the Hydraulic Performance of Bulb Tubular Turbine
Authors: Fu Yongyuan , Wu Guangkuan , Feng Jianjun , Zhu Guojun 
Published: March 2021

Abstract
In engineering applications, anti-cavitation edges are often added at the blade’s suction surface. The internal flow field of the bulb tubular turbine is numerical simulated using ANSYS CFX-19.2 to understand the influence of the anti-cavitation edge. Four geometric models are adopted for investigation, i.e., no anti-cavitation edge, 2mm, 3mm and 4mm thickness anti-cavitation edge. The results show that the efficiency of the runner increases with the anti-cavitation edge. As the thickness of the anti-cavitation edge increases, the clearance flow rate decreases. The clearance leakage vortex is pushed away from the blade’s suction surface and its inception is far away from the blade’s inlet. Moreover, the strength for clearance leakage vortex decreases under the effect of the anti-cavitation edge, which reduces the damage to the runner blade.
Study on Optimization of Control Strategy for Pump Shutdown in Pumped-Storage Unit
Authors: Bi Zhiwei , Wei Jiafu , Zhao Bushi , Hou Kai , Zhang Yike , Zhang Yuncheng , Chen Shengsheng 
Published: March 2021

Abstract
In view of the formulation of power failure control strategy of pumped-storage unit at pump operation condition caused by hydraulic, mechanical and electrical factors, taking Heimifeng pumped-storage power station as an example, downtime control strategy at the pump working condition were analyzed under different heads. The transition characteristics at the pump condition of power outage for different guide vane opening were discussed. The stability parameter variation characteristics for the key points of vibration/sway and pressure pulsation at the process of shutdown were analyed. Combination the GCB characteristics of unit, the optimal load and the guide vane opening in the power outage process of shutdown at pump working condition were determined, and the electric life. The optimized shutdown strategy can ensure the safe operation of the unit, and the shutdown load can meet the requirements of the industry standard.
Research and Application on Numerical Simulation of Hydraulic Transients in Complex Water Conveyance System
Authors: Zhou T C , Li G H , Chen X R , Wu X M , Pan Y B 
Published: March 2021

Abstract
Accurate simulation of hydraulic transients is crucial and complicated in the design of hydropower station and pumped storage power station. In this paper, key technologies for hydraulic transient simulation calculation in complex water conveyance system were studied. The structural matrix method with advantages of high accuracy and fast speed for numerical calculation was introduced. Complicated elements in the conveyance system were refined, such as high precision simulation of differential surge chamber, simulation of long and narrow upper chamber, new interpolation method for characteristic curve of pumped storage unit. Based on Jinping II hydropower station with special long headrace system and differential surge chamber, Baihetan hydropower station with complex tailrace system and large surge chamber and Xianyou pumped storage power station with complex unit characteristics and various working conditions, the application of the simulation software HYSIM in field test and inversion calculation was illustrated. The paper providing references for the design of similar projects.
Research and Development of Management and Control System for Lake Sediment Improvement and Dehydration Treatment
Authors: Liu Gongxun , Liang Xin , Zhang Qingbo , Liu Ruoyuan , Hong Guojun , Zheng Shihua , Zhong Huangliang , Liu Kuilong 
Published: March 2021

Abstract
Relying on the water environment improvement project of Wuhan East Lake, an intelligent management and control system for river and lake sediment dredging and solidification treatment is developed based on the integrated treatment technology of sediment dredging and solidification. The system is mainly composed of dredging vessel positioning and digging depth monitoring subsystem, dehydration and drying integrated optimization control subsystem, safety monitoring subsystem, earthwork automatic measurement subsystem and comprehensive management subsystem. Through real-time monitoring, collection and analysis of data, from the real-time adjustment of dredger construction parameters to the matching of quality and process parameters of plate and frame machine pressure filtration, and then to the whole life cycle of earthwork automatic measurement and comprehensive efficiency, cost analysis, personnel situation, project progress and production safety, comprehensive intelligent operation and control is realized. The system has been successfully applied to the water environment improvement project of Wuhan East Lake and achieved remarkable results. It not only ensures the quality of sediment dredging and drying treatment, but also greatly improves the production efficiency and ensures the production safety. Through real-time monitoring, collection and analysis of data, from the real-time adjustment of dredger construction parameters to the matching of quality and process parameters of plate and frame machine pressure filtration, and then to the whole life cycle of earthwork automatic measurement and comprehensive efficiency, cost analysis, personnel situation, project progress and production safety, comprehensive intelligent operation and control is realized. The system has been successfully applied to the water environment improvement project of Wuhan East Lake and achieved remarkable results. It not only ensures the quality of sediment dredging and drying treatment, but also greatly improves the production efficiency and ensures the production safety.