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Error analysis of the numerical method for correcting the propagation of EM waves in the troposphere

Journal of Microwaves, Optoelectronics and Electromagnetic Applications 2020年第3期19卷 407-414页

作者： Liu, Yuanzhi Tang, Tao Liu, Guo Olaimat, M. Science and Technology on Electronic Information Control Laboratory Southwest China Research Institute of Electronic Equipment Chengdu610036 China College of Electronic Engineering Chengdu University of Information Technology Chengdu610025 China Department of Electrical and Computer Engineering University of Waterloo WaterlooN2L 3G1 Canada School of Electrical Engineering and Computer Science University of Ottawa OttawaK1N 6N5 Canada Key laboratory of Atmospheric Sounding China Meteorological Administration Chengdu610225 China

Electromagnetic (EM) waves do not travel in straight lines in the troposphere due to refraction. This leads to errors in many engineering applications. In order to correct these errors, a numerical solution based on the difference method has been proposed, which can reveal the degree of EM wave bending owing to atmospheric refraction, moreover, it can predict the actual path of the EM wave propagating in the troposphere. The error of the numerical method is studied here, which reveals the source of the error. Based on this, two improvement methods are proposed. The computational accuracy of the numerical methods is verified by comparison with the analytical solution. The proposed method ensures the computational efficiency and accuracy of the problem of refraction of EM waves in the troposphere. © 2020 SBMO/SBMag

关键词： Error analysis

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Inverted XML Access control Model Based on Ontology Semantic Dependency

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computers, Materials & Continua 2018年第6期55卷 465-482页

作者： Meijuan Wang Jian Wang Lihong Guo Lein Harn College of Computer Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing210016China Command&Control Engineering College Army Engineering University of PLANanjing 210007China Department of Communications Engineering Nanjing Institute of TechnologyNanjing 211167China University of Missouri Kansas CityAmerican

In the era of big data,the conflict between data mining and data privacy protection is increasing day by *** information security focuses on protecting the security of attribute values without semantic *** data privacy of big data is mainly reflected in the effective use of data without exposing the user’s sensitive *** the semantic association,reasonable security access for privacy protect is ***-structured and self-descriptive XML(eXtensible Markup Language)has become a common form of data organization for database management in big data *** on the semantic integration nature of XML data,this paper proposes a data access control model for individual *** the semantic dependency between data and the integration process from bottom to top,the global visual range of inverted XML structure is *** results show that the model effectively protects the privacy and has high access efficiency.

关键词： Privacy protection access control semantic dependence inverted XML global view

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Fast ORB-SLAM without Keypoint Descriptors

arXiv

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arXiv 2020年

作者： Fu, Qiang Yu, Hongshan Wang, Xiaolong Yang, Zhengeng He, Yong Zhang, Hong Mian, Ajmal The National Engineering Laboratory for Robot Visual Perception and Control Technology College of Electrical and Information Engineering Hunan University China The Department of Computing Science University of Alberta Canada Quanzhou Institute of Industrial Design and Machine Intelligence Innovation Hunan University China The Southern University of Science and Technology Shenzhen China The School of Mathematics and Information Science Shaanxi Normal University China The Department of Computer Science The University of Western Australia WA6009 Australia

Indirect methods for visual SLAM are gaining popularity due to their robustness to environmental variations. ORB-SLAM2 [1] is a benchmark method in this domain, however, it consumes significant time for computing descriptors that never get reused unless a frame is selected as a keyframe. To overcome these problems, we present FastORB-SLAM which is light-weight and efficient as it tracks keypoints between adjacent frames without computing descriptors. To achieve this, a two stage descriptor-independent keypoint matching method is proposed based on sparse optical flow. In the first stage, we predict initial keypoint correspondences via a simple but effective motion model and then robustly establish the correspondences via pyramid-based sparse optical flow tracking. In the second stage, we leverage the constraints of the motion smoothness and epipolar geometry to refine the correspondences. In particular, our method computes descriptors only for keyframes. We test FastORB-SLAM on TUM and ICL-NUIM RGB-D datasets and compare its accuracy and efficiency to nine existing RGB-D SLAM methods. Qualitative and quantitative results show that our method achieves state-of-the-art accuracy and is about twice as fast as the ORB-SLAM2. Copyright © 2020, The Authors. All rights reserved.

关键词： Optical flows

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ARIMA Models for Predicting the End of COVID-19 Pandemic and the Risk of a Second Rebound

Research Square

引用

Research Square 2020年

作者： Malki, Zohair Atlam, El-Sayed Ewis, Ashraf Dagnew, Guesh Alzighaibi, Ahmad Reda Elmarhomy, Ghada Elhosseini, Mostafa A. Hassanien, Aboul Ella Gad, Ibrahim College of Computer Science and Engineering Taibah University Yanbu Saudi Arabia Faculty of Science Tanta University Egypt Department of Public Health and Occupational Medicine Faculty of Medicine Minia University El-Minia Egypt Department of Public Health Faculty of Health Sciences – AlQunfudah Umm AlQura University Mecca Saudi Arabia Department of Computer Science Institute of Technology Dire Dawa University Ethiopia Mansoura University Computers Engineering and Control Systems Department Faculty of Engineering Mansoura Egypt Faculty of Computers and Artificial Intelligence Cairo University Egypt

Globally, many research works are going on to study the infectious nature of COVID-19 and every day we learn something new about it through the flooding of the huge data that are accumulating hourly rather than daily which instantly opens hot research topics for artificial intelligence researchers. However, the public’s concern by now is to find answers for two questions;1) when this COVID-19 pandemic will be over? and 2) After coming to its end, will COVID-19 return again in what is known as a second rebound of the pandemic?. This research developed a predictive model that can estimate the expected period of time that the virus can possibly stopped and the risk of a second rebound of COVID-19 pandemic. Therefore, this study considered SARIMA model to predict the spread of the virus on several selected countries and is used for pandemic life cycle and end date predictions. The study can be applied to predict the same for other countries as the nature of the virus is the same everywhere. The advantages of this study are that it helps the governments in making decisions and planning now for the future, reduces anxiety and prepares the mentality of people for the next phases of the pandemic. The most striking finding to emerge from this experimental and simulation study is that the proposed algorithm show that the expected COVID-19 infections for the top countries of highest number of confirmed case will slowdown in October, 2020. Moreover, our study forecasts that there may be a second rebound of the pandemic in a year time, if the current taken precautions are eased completely. We have to consider the uncertain nature of the current COVID-19 pandemic and the growing inter-connected and complex world, what are ultimately required are the flexibility, robustness and resilience to cope up the unexpected future events and scenarios. © 2020, CC BY.

关键词： COVID-19

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PID Tuning Of Chopper Fed Speed control Of DC Motor Based On Ant Colony Optimization Algorithm

PID Tuning Of Chopper Fed Speed Control Of DC Motor Based On...

引用

China International Electrical and Energy Conference (CIEEC)

作者： Bonzou Adolphe Kouassi Yiming Zhang Sie Ouattara Mesmin J. Mbyamm Kiki College of Electronic Information and Control Engineering Beijing University of Technology Beijing China College of Computer Science and Technology Beijing University of Technology Beijing China

ISBN: (数字)9781728116754

ISBN: (纸本)9781728116761

Problems of optimization are very important for both the worlds of sciences and industry. Owing to their practicality such as tiny dimensions, velocity, lower building costs, safety operations, DC motor has been used as a key aspect of industrial applications. However, it is hard to acquire the correct controlling parameter values. The most common control is the PID (Proportional-Integrated-Derivative) controller due to its efficiency and simple *** paper provides an approach of determining the optimum control parameters of PID for the Chopper Fed speed motor control using the Ant Colony Optimization (ACO). The efficiency and validity of the design method based on ACO are shown in the Simulation outcomes.

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H∞ Model-free Reinforcement Learning with Robust Stability Guarantee

arXiv

引用

arXiv 2019年

作者： Han, Minghao Zhang, Lixian Tian, Yuan Wang, Jun Pan, Wei Department of Control Science and Engineering Harbin Institute of Technology Department of Cognitive Robotics Delft University of Technology Department of Computer Science University College London

Reinforcement learning is showing great potentials in robotics applications, including autonomous driving, robot manipulation and locomotion. However, with complex uncertainties in the real-world environment, it is difficult to guarantee the successful generalization and sim-to-real transfer of learned policies theoretically. In this paper, we introduce and extend the idea of robust stability and H∞ control to design policies with both stability and robustness guarantee. Specifically, a sample-based approach for analyzing the Lyapunov stability and performance robustness of a learning-based control system is proposed. Based on the theoretical results, a maximum entropy algorithm is developed for searching Lyapunov function and designing a policy with provable robust stability guarantee. Without any specific domain knowledge, our method can find a policy that is robust to various uncertainties and generalizes well to different test environments. In our experiments, we show that our method achieves better robustness to both large impulsive disturbances and parametric variations in the environment than the state-of-art results in both robust and generic RL, as well as classic control. Anonymous code is available to reproduce the experimental results at https://***/RobustStabilityGuaranteeRL/RobustStabilityGuaranteeRL. Copyright © 2019, The Authors. All rights reserved.

关键词： Reinforcement learning

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An exploratory study on machine learning to couple numerical solutions of partial differential equations

arXiv

引用

arXiv 2020年

作者： Tang, Hansong Li, L. Grossberg, M. Liu, Y.J. Jia, Y.M. Li, S.S. Dong, W.B. Civil Engineering Department City College of New York City University of New York New York10031 United States Department of Control Science and Engineering University of Shanghai for Science and Technology Shanghai200093 China Department of Computer Science City College of New York City University of New York New York10031 United States School of Mathematics Georgia Institute of Technology GA30332 United States School of Automation Science and Electrical Engineering Beihang University Beijing10083 China School of Hydraulic and Hydroelectric Engineering Xi'an University of Technology Shaanxi710048 China

As further progress in the accurate and efficient computation of coupled partial differential equations (PDEs) becomes increasingly difficult, it has become highly desired to develop new methods for such computation. In deviation from conventional approaches, this short communication paper explores a computational paradigm that couples numerical solutions of PDEs via machine-learning (ML) based methods, together with a preliminary study on the paradigm. Particularly, it solves PDEs in subdomains as in a conventional approach but develops and trains artificial neural networks (ANN) to couple the PDEs' solutions at their interfaces, leading to solutions to the PDEs in the whole domains. The concepts and algorithms for the ML coupling are discussed using coupled Poisson equations and coupled advection-diffusion equations. Preliminary numerical examples illustrate the feasibility and performance of the ML coupling. Although preliminary, the results of this exploratory study indicate that the ML paradigm is promising and deserves further research. Copyright © 2020, The Authors. All rights reserved.

关键词： Neural networks

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An Improved Ant Colony Optimization Algorithm Based on Fractional Order Memory for Traveling Salesman Problems

An Improved Ant Colony Optimization Algorithm Based on Fract...

引用

IEEE Symposium Series on Computational Intelligence (SSCI)

作者： Xiaoling Gong Ziheng Rong Tao Gao Yifei Pu Jian Wang College of Control Science and Engineering China University of Petroleum (East China) Qingdao China College of Science China University of Petroleum (East China) Qingdao China College of Computer Science Sichuan University Chengdu China

ISBN: (数字)9781728124858

ISBN: (纸本)9781728124865

Ant Colony Optimization (ACO) algorithm has a wide array of applications to solve combinatorial optimization problems, especially Traveling Salesman Problems (TSPs). The major limitations of ACO algorithm are premature convergence, the possibility that trapped in the local optima. In this paper, an improved Ant Colony Optimization algorithm is proposed which uses fractional order difference for pheromone updating and a weighted combined transition probability. The fractional order difference with the characteristic of long-term memory helps the algorithm make full use of the historical information, and the combined transition probability enhances the exploration ability of the algorithm by using the information of a few steps forward. The performance of the proposed algorithm is tested on various data sets from the standard TSP Library compared with the corresponding integer order algorithm and some evolutionary algorithms. According to the empirical results, our algorithm based on fractional order difference overcomes the classic integer order. Furthermore, the results on a number of TSP instances demonstrate that compared with other evolutionary algorithms, the proposed method can obtain the better solutions on most instances with stronger robustness.

关键词： Urban areas Optimization Signal processing algorithms Fractional calculus Heuristic algorithms Ant colony optimization Traveling salesman problems

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A Green Paradigm for Internet of Things: Ambient Backscatter Communications

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China Communications 2019年第7期16卷 109-119页

作者： Wei Zhang Yao Qin Wenjing Zhao Minzheng Jia Qiang Liu Ruisi He Bo Ai Science and Technology on Information Systems Engineering Laboratory National University of Defense Technology and also with Institute of Telecommunication Satellites China Academy of Space Technology (CAST) Beijing Key Lab of Transportation Data Analysis and Mining Beijing Engineering Research Center of High-Speed Railway Broadband Mobile Communications School of Computer and Information Technology Beijing Jiaotong University Beijing 100044 China Department of Information Engineering Beijing Polytechnic College Beijing 100042 China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing 100044 China

Internet of Things (IoT) has attracted extensive interest from both academia and industries, and is recognized as an ultimate infrastructure to connect everything at anytime and anywhere. The implementation of IoT generally faces the challenges from energy constraint and implementation cost. In this paper, we will introduce a new green communication paradigm, the ambient backscatter (AmBC), that could utilize the environmental wireless signals for both powering a tiny-cost device and backscattering the information symbols. Specifically, we will present the basic principles of AmBC, analyze its features and advantages, suggest its open problems, and predict its potential applications for our future IoT.

关键词： ambient backscatter (AmBC) RF-powered device Internet of Things (IoT) battery-free tag wire-less sensor

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Fuzzy Rate Analysis of Operators and its Applications in Linear Spaces

Research Square

引用

Research Square 2021年

作者： Zhang, Yijin Li, Honggang Jin, Maoming Lin, Zongbing Nanjing Changjiang Waterway Engineering Bureau China Key Lab of Intelligent Analysis and Decision on Complex Systems Key Laboratory of Industrial Internet of Things and Networked Control Ministry of Education Chongqing University of Posts and Telecommunications Chongqing400065 China Pass College Chongqing Technology and Business University Chongqing401520 China Institute of Nonlinear Analysis Research Changjiang Normal University Chongqing400803 China School of Mathematics and Computer Science Panzhihua University Panzhihua617000 China

In this paper, a new concept, the fuzzy rate of an operator in linear spaces is proposed for the very first time. Some properties and basic principles of it are studied. Fuzzy rate of an operator B which is specific i... 详细信息

关键词： Membership functions

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