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Time-series unmanned aerial vehicle photogrammetry monitoring method without ground control points to measure mining subsidence

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JOURNAL OF APPLIED REMOTE SENSING 2021年第2期15卷

作者： Lian, Xugang Liu, Xiaoyu Ge, Linlin Hu, Haifeng Du, Zheyuan Wu, Yanru Taiyuan Univ Technol Sch Min Engn Taiyuan Peoples R China Univ New South Wales Sch Civil & Environm Engn Sydney NSW Australia

Surface subsidence and its secondary effects caused by underground coal mining continually threaten the safety and property of residents in mining areas. The commonly used total station and leveling approach is time-consuming and laborious, and the spatial range is limited. In this study, an FEIMA D2000 quadrotor unmanned aerial vehicle (UAV) was used to conduct 4-cm/pixel photogrammetry in four trial periods over a surface influence area (3.75 km(2)) of a working mine face. The performance comparison experiments from five point-cloud filtering algorithms in two sub-regions of the study area show that the ATIN algorithm provides the best filtering for this study area. Coal mining subsidence monitoring in mountainous area based on time-series UAV photogrammetry technology is proposed. Using this approach, the ATIN algorithm was used to filter the overall point cloud data in the study area to obtain the digital elevation model (DEM). The surface dynamic subsidence basin was determined with two phases of DEM subtraction. The results show that, compared with the measured leveling data in the field in the same period, the average root mean square error is 165 mm, and the maximum subsidence monitoring accuracy reaches 98%. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： unmanned aerial vehicle photogrammetry subsidence monitoring filtering algorithm surface subsidence basin

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Design of 4PUS-PPPS redundant parallel mechanism oriented to the visual system of flight simulator

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INTERNATIONAL JOURNAL OF INTELLIGENT ROBOTICS AND APPLICATIONS 2021年第4期5卷 534-542页

作者： Ren, Bin Zhang, Zhiqiang Shanghai Univ Sch Mechatron Engn & Automat Shanghai Key Lab Intelligent Mfg & Robot Shanghai 200444 Peoples R China

The Design of the flight simulator mechanism is an essential link in the development of aviation technology. The six-degree-of-freedom Stewart parallel mechanism is used as the mechanical body of most traditional flight simulators. They can simulate the six-degree-of-freedom motion of the aircraft. However, the reachable attitude of the moving platform of the Stewart parallel mechanism is relatively small, and its range of motion is +/- 35 degrees, which can only achieve a small range of yaw, roll and pitch. It can only satisfy the simulation of the attitude change of a civil aviation aircraft. A 4PUS-PPPS redundant parallel mechanism equipped with visual function is proposed to simulate the high motion performance of fighter aircraft, which can realize the movement of angles (- 90 degrees,178 degrees) around the horizontal axis of the aircraft. The flight attitude data of the aircraft were acquired and processed by filtering algorithms in the software of Unity 3D environment. Then, the three steering gears that simulate the action of the moving platform are controlled by the processed data, which realizes the simulation control of the combination of virtual and honest and provides a new idea for the research of redundant parallel mechanisms.

关键词： Flight simulator Redundant parallel mechanism Visual function filtering algorithm

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A Novel Teaching Approach for Mobile Internet-Based Collaborative Knowledge Construction in "Teaching Management"

INTERNATIONAL JOURNAL OF EMERGING TECHNOLOGIES IN LEARNING

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INTERNATIONAL JOURNAL OF EMERGING TECHNOLOGIES IN LEARNING 2021年第12期16卷 51-64页

作者： Zhang, Sheng Bangkok Thonburi Univ Educ Bangkok Thailand

With the development of education, teaching, as the basic and central work at school, is conducted most frequently with the largest workload. In simple words, teaching management for the purpose of the management of teaching work is an essential content of school management, as well as a basic activity of school leaders. Therefore, more than just the basis and guarantee for the normal operation of school teaching, teaching management course plays a critical role in teacher growth and education reform, has great significance for schools. However, problems in current teaching management courses, such as lack of teacher-student interaction, single teaching content, and simple teaching methods have hindered students to develop interest in learning, and impede teachers to give full play to their educational personality. In this paper, a new collaborative knowledge construction teaching approach was applied in mobile Internet technology environment, and a blended teaching model of students' online autonomous collaborative learning before class, knowledge internalization in class, and leak filling after class was proposed. At the same time, the personalized recommendation technology based on collaborative filtering algorithm was applied. Firstly, mobile terminal core information was collected from the mobile Internet learning platform for preprocessing, and then the processed data were identified by the collaborative filtering algorithm to recognize the intrusion data, thereby realizing the quick screening and accurate pushing of learning resources. It was found from the teaching practice that this model can effectively enhance students' interest in learning, improve learning effects and independent innovation capabilities.

关键词： Mobile internet teaching management collaborative knowledge filtering algorithm

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A novel trust recommendation model for mobile social network based on user motivation

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ELECTRONIC COMMERCE RESEARCH 2021年第3期21卷 809-830页

作者： Yang, Gelan Yang, Qin Jin, Huixia Hunan City Univ Dept Comp Yiyang 413000 Peoples R China Sichuan Agr Univ Sch Business Dujiangyan 611830 Peoples R China Hunan City Univ Dept Informat Sci & Engn Yiyang 413000 Peoples R China

Traditional collaborative filtering recommendation algorithm has the problems of sparse data and limited user preference information. To deal with data sparseness problem and the unreliability phenomenon on the traditional social network recommendation. This paper presents a novel algorithm based on trust relationship reconstruction and social network delivery. This paper introduces the method of eliminating falsehood and storing truth to avoid the unreliable phenomenon and improves the accuracy of falsehood according to the user similarity formula based on the scale of contact established by users. In this paper, the problem of attack caused by the misbehaving nodes is investigated when the recommended information is disseminated in the existing trust model. In addition, a recommendation-based trust model is proposed that includes a defensive plan. This scheme employs the clustering techniques on the basis of interaction count, information Compatibility and node intimacy, in a certain period of time dynamically filter dishonest recommendation related attacks. The model has been verified in different portable and detached topologies. The network knots undergo modifications regarding their neighbors as well as frequent routes. The experimental analysis indicates correctness and robustness of the reliance system in an active MANET setting. Compared with the most advanced recommender system, the proposed recommendation algorithm in accuracy and coverage measurements show a significant improvement.

关键词： Trust relationship Mobile social network filtering algorithm Recommendation attack Recommendation management

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Updating numerical models towards time domain alignment of structural dynamic responses with a limited number of sensors

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MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2023年 204卷

作者： Fu, Yuhao Wang, Ying Harbin Inst Technol Shenzhen Sch Civil & Environm Engn Shenzhen 518055 Guangdong Peoples R China Guangdong Prov Key Lab Intelligent & Resilient Str Shenzhen Guangdong Peoples R China

Due to the inherent uncertainty and complexity of civil infrastructure, it is challenging to simulate their structural dynamic responses accurately and efficiently. Existing model updating methods normally need distributed sensors and use modal parameters to construct objective functions, which can achieve frequency domain agreement between the numerical model and the real structure. Nevertheless, time domain alignment is still difficult to achieve, especially when the sensor number is limited. To enhance the simulation accuracy, this paper proposes a two-step model updating approach through updating in frequency and time domains sequentially. A virtual force is introduced in the second step to represent structural complexity and input error, and is derived by using three representative algorithms. The approach was verified on a scaled wind turbine model in the laboratory. Parametric studies were performed on different arrangements of sensors and virtual force. The results show that the virtual force should be placed at a sensor point and close to the acting point of external loads. The approach can achieve time domain alignment between numerical model and real structure with a normalized mean square error averaging 3.25% in the optimal setting. Based on the results, the proposed framework may find vast application in the establishment of numerical models towards structural dynamic twins.

关键词： Virtual force Force identification System identification filtering algorithm Structural health monitoring

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Optimal filtering and control for wireless networked closed-loop control systems

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INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING 2020年第10期34卷 1466-1482页

作者： Dong, Jianhuai Dong, Zhixuan Fujian Jiangxia Univ Coll Elect & Informat Sci Fuzhou 350108 Peoples R China Fudan Univ Sch Microelect Shanghai Peoples R China

This article studies the optimal filtering and control for wireless networked control systems (WNCSs). In WNCSs, packets may be lost in both control and feedback channels and user datagram protocol is usually used to improve the performance of the real-time control. Relevant literature indicates that the conventional optimal filtering for such a system cannot be applied in practice due to the complex calculation with Gaussian mixtures. This paper proposes a novel scheme to realize the optimal filtering and the linear quadratic Gaussian control for WNCSs, in which the controlled node performs a local estimation and the remote-control node performs the final estimation and control, and a synchronization of two estimators is guaranteed by a communication mechanism. An optimal filtering algorithm is developed, the stability condition of the filtering error covariance is obtained, optimal finite-horizon and infinite-horizon control are derived, and the stability of the closed-loop control system is proved. Numerical simulations show the validity and feasibility of the theoretical results.

关键词： communication mechanism filtering algorithm LQG control packet loss stability wireless networked control systems

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Image Enhancement from Illumination Variation to Improve the Performance of Simultaneous Localization and Mapping Technique 4

Image Enhancement from Illumination Variation to Improve the...

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4th International Conference on Information and Computer Technologies (ICICT)

作者： Agunbiade, O. Y. Zuva, T. Vaal Univ Technol Dept Informat Technol Vanderbijlpk ZA-1900 Gauteng South Africa

ISBN: (纸本)9781665413992

The Simultaneous Localization and Mapping (SLAM) is a research problem that has been explored by scholars. The SLAM contribution to autonomous robot navigation has attracted the attention of many researchers and over the decades, many SLAM techniques with outstanding achievement has been presented to resolve the SLAM problem. However, there are factors such as environmental noises that can limit the performance of SLAM techniques. These environmental noises can create misunderstandings in image analysis with an erroneous effect on the robot navigation path. In this study, attention will only focus on shadow and light intensity environmental noise and in resolving this issue, filters were presented to modify the original Monte Carlo algorithm to improve its effectiveness. MATLAB was used for the simulation experiment and evaluation is based on qualitative and quantitative methods. The experimental results acquired were compared to the original Monte Carlo algorithm without filters and the results obtained were amazing. The accomplishment of the modified Monte Carlo algorithm has led to enhancement in robot path and in real-life implementation will facilitate self-directed navigation, exploration, and route planning while it decreases accident rates and injuries for human working in an unstable environment.

关键词： Autonomous robot Trajectory Navigation filtering algorithm Kidnap problem Dynamic Environment Simultaneous Localization and Mapping

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Analysis of Time Domain Characteristic of Transformer On-load Tap-changer 6

Analysis of Time Domain Characteristic of Transformer On-loa...

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6th International Conference on Integrated Circuits and Microsystems (ICICM)

作者： Yu Bing Zhao Lin Lin Haofan Yang Yong State Grid Zhejiang Elect Power Res Inst Hangzhou Peoples R China

ISBN: (纸本)9781665458863

On-load tap-changer is a switching device that provides a constant voltage for a transformer when the load changes. The basic principle is to realize the switching between taps in the transformer winding without interrupting the load current, thereby changing the number of winding turns, that is, the voltage ratio of the transformer, and finally achieving the purpose of voltage regulation. In this paper, the characteristic parameters are collected by time domain analysis method, which provides the basis for discriminating the later fault warning.

关键词： on-load tap-changer change-over switch selector adaptive morphology filtering algorithm wavelet transform

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Design of Lung Sound Acquisition and Analysis Device 22

Design of Lung Sound Acquisition and Analysis Device

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Proceedings of the 2022 5th International Conference on Telecommunications and Communication Engineering

作者： Hao Huang Wugang Lai Fanqiang Lin College of Mechanical and Electrical Engineering Chengdu University of Technology China

ISBN: (纸本)9781450397797

As a lung examination instrument, lung sound stethoscope has been widely used. However, the results of traditional diagnosis are often affected by stethoscope and doctor's experience. In this paper, a design of lung sound acquisition and analysis device is proposed, which can complete the function of lung sound acquisition and drawing lung sound waveform, provide doctors with intuitive lung sound information, and provide a possibility for the diagnosis of respiratory diseases and quantitative analysis of pathological lung sounds. This device consists of lung sound acquisition terminal, transmission module and Android user terminal. The acquisition terminal can collect the lung sound signal of the patient and transmit it to the Android terminal through the transmission module. Users can perform operations such as audio playback, waveform display, and data storage on the Android terminal. The test results show that the device can realize the acquisition and analysis of 10Hz ∼ 3KHz signal, and achieve the expected experimental effect.

关键词： filtering algorithm Android Lung sound stethoscope Embedded system Separation of heart and lung sounds

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Applying a Robust Empirical Method for Comparing Repeated LiDAR Data with Different Point Density

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FORESTS 2022年第3期13卷 380页

作者： Viedma, Olga Univ Castilla La Mancha Dept Environm Sci Avda Carlos 3 Toledo 45071 Spain

A key aspect of vegetation monitoring from LiDAR is concerned with the use of comparable data acquired from multitemporal surveys and from different sensors. Accurate digital elevation models (DEMs) to derive vegetation products, are required to make comparisons among repeated LiDAR data. Here, we aimed to apply an improved empirical method based on DEMs of difference, that adjust the ground elevation of a low-density LiDAR dataset to that of a high-density LiDAR one for ensuring credible vegetation changes. The study areas are a collection of six sites over the Sierra de Gredos in Central Spain. The methodology consisted of producing "the best DEM of difference" between low- and high-density LiDAR data (using the classification filter, the interpolation method and the spatial resolution with the lowest vertical error) to generate a local "pseudo-geoid" (i.e., continuous surfaces of elevation differences) that was used to correct raw low-density LiDAR ground points. The vertical error of DEMs was estimated by the 50th percentile (P-50), the normalized median absolute deviation (NMAD) and the root mean square error (RMSE) of elevation differences. In addition, we analyzed the effects of site-properties (elevation, slope, vegetation height and distance to the nearest geoid point) on DEMs accuracy. Finally, we assessed if vegetation height changes were related to the ground elevation differences between low- and high-density LiDAR datasets. Before correction and aggregating by sites, the vertical error of DEMs ranged from 0.02 to -2.09 m (P-50), from 0.39 to 0.85 m (NMDA) and from 0.54 to 2.5 m (RMSE). The segmented-based filter algorithm (CSF) showed the highest error, but there were not significant differences among interpolation methods or spatial resolutions. After correction and aggregating by sites, the vertical error of DEMs dropped significantly: from -0.004 to -0.016 m (P-50), from 0.10 to 0.06 m (NMDA) and from 0.28 to 0.46 m (RMSE);and the CSF filter algorit

关键词： multitemporal LiDAR DEMs of difference filtering algorithm vertical error pseudo-geoid vegetation growth

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