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353 results on '"Zhang, Guidong"'

1. Hands-on Wireless Sensing with Wi-Fi: A Tutorial

Author

Yang, Zheng, Zhang, Yi, Chi, Guoxuan, and Zhang, Guidong

Subjects
Electrical Engineering and Systems Science - Signal Processing, Computer Science - Artificial Intelligence, Computer Science - Human-Computer Interaction, Computer Science - Networking and Internet Architecture
Abstract

With the rapid development of wireless communication technology, wireless access points (AP) and internet of things (IoT) devices have been widely deployed in our surroundings. Various types of wireless signals (e.g., Wi-Fi, LoRa, LTE) are filling out our living and working spaces. Previous researches reveal the fact that radio waves are modulated by the spatial structure during the propagation process (e.g., reflection, diffraction, and scattering) and superimposed on the receiver. This observation allows us to reconstruct the surrounding environment based on received wireless signals, called "wireless sensing". Wireless sensing is an emerging technology that enables a wide range of applications, such as gesture recognition for human-computer interaction, vital signs monitoring for health care, and intrusion detection for security management. Compared with other sensing paradigms, such as vision-based and IMU-based sensing, wireless sensing solutions have unique advantages such as high coverage, pervasiveness, low cost, and robustness under adverse light and texture scenarios. Besides, wireless sensing solutions are generally lightweight in terms of both computation overhead and device size. This tutorial takes Wi-Fi sensing as an example. It introduces both the theoretical principles and the code implementation of data collection, signal processing, features extraction, and model design. In addition, this tutorial highlights state-of-the-art deep learning models (e.g., CNN, RNN, and adversarial learning models) and their applications in wireless sensing systems. We hope this tutorial will help people in other research fields to break into wireless sensing research and learn more about its theories, designs, and implementation skills, promoting prosperity in the wireless sensing research field.

Published
2022

6. Estimating Unknown Time-Varying Parameters in Uncertain Differential Equation

Author

Zhang, Guidong and Sheng, Yuhong

Subjects
Statistics - Methodology
Abstract

Uncertain differential equations have a wide range of applications. How to obtain estimated values of unknown parameters in uncertain differential equations through observations has always been a subject of concern and research, many methods have been developed to estimate unknown parameters. However, these parameters are constants. In this paper, the method of least squares estimation is recast for estimating the unknown time-varying parameters in uncertain differential equations. A set of unknown time-varying parameter estimates will be obtained, and then the unknown time-varying parameters will be obtained by regression fitting using the estimated values. Using this method, the uncertain differential equation of blood alcohol concentration in human body after drinking and the uncertain differential equation of COVID-19 are derived.

Published
2021

13. Variable selection for uncertain regression models based on elastic net method.

Author

Zhang, Guidong, Zhao, Wenzhi, and Sheng, Yuhong

Subjects
*REGRESSION analysis, *TEST methods, *SIMPLICITY, *HYPOTHESIS
Abstract

AbstractOn one hand, determining the exact number of explanatory variables in uncertain regression analysis is often challenging, as real-world scenarios are interconnected. On the other hand, it’s worth noting that even when the number of variables is determined, some variables may have minimal impact on the response variable, and retaining them would only increase the complexity of the model. Therefore, variable selection methods can help eliminate variables with minimal impact to enhance the simplicity and interpretability of the model. In light of this, this paper first introduces a novel variable selection strategy based on the elastic net method to address the variable selection problem in uncertain regression models. This method not only offers the flexibility to simplify uncertain regression analysis into Lasso estimation or Ridge estimation but also exhibits extremely high efficiency in variable selection. Secondly, to address the issue of determining tuning parameters, we introduce the cross-validation method to ensure optimal model performance. Furthermore, we propose an uncertain hypothesis testing method based on imprecise observational data, which can help us assess the suitability of estimated parameters. Finally, through a series of numerical examples, we validate the feasibility and effectiveness of this method. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Cyber Security Situation Prediction Model Based on GWO-SVM

Author

Lu, Hongxia, Zhang, Guidong, Shen, Yongjun, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Barolli, Leonard, editor, Xhafa, Fatos, editor, and Hussain, Omar K., editor

Published
2020
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16. GaitID: Robust Wi-Fi Based Gait Recognition

Author

Zhang, Yi, Zheng, Yue, Zhang, Guidong, Qian, Kun, Qian, Chen, Yang, Zheng, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Yu, Dongxiao, editor, Dressler, Falko, editor, and Yu, Jiguo, editor

Published
2020
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19. XFall: Domain Adaptive Wi-Fi-Based Fall Detection With Cross-Modal Supervision

Author

Chi, Guoxuan, Zhang, Guidong, Ding, Xuan, Ma, Qiang, Yang, Zheng, Du, Zhenguo, Xiao, Houfei, and Liu, Zhuang

Abstract

Recent years have witnessed an increasing demand for human fall detection systems. Among all existing methods, Wi-Fi-based fall detection has become one of the most promising solutions due to its pervasiveness. However, when applied to a new domain, existing Wi-Fi-based solutions suffer from severe performance degradation caused by low generalizability. In this paper, we propose XFall, a domain-adaptive fall detection system based on Wi-Fi. XFall overcomes the generalization problem from three aspects. To advance cross-environment sensing, XFall exploits an environment-independent feature called speed distribution profile, which is irrelevant to indoor layout and device deployment. To ensure sensitivity across all fall types, an attention-based encoder is designed to extract the general fall representation by associating both the spatial and temporal dimensions of the input. To train a large model with limited amounts of Wi-Fi data, we design a cross-modal learning framework, adopting a pre-trained visual model for supervision during the training process. We implement and evaluate XFall on one of the latest commercial wireless products through a year-long deployment in real-world settings. The result shows XFall achieves an overall accuracy of 96.8%, with a miss alarm rate of 3.1% and a false alarm rate of 3.3%, outperforming the state-of-the-art solutions in both in-domain and cross-domain evaluation.

Published
2024
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28. A simplified model and its parameters optimization methodology of LCC‐S WPT compensation network under dual‐side‐detuned conditions.

Author

Li, Zhizhong, Han, Fei, and Zhang, Guidong

Subjects
WIRELESS power transmission, COUPLINGS (Gearing)
Abstract

Wireless power transfer (WPT) systems typically operate under broad coupling conditions. In response to the issue of significant fluctuations in output power due to changes in the coupling coefficient when the coupling coils are offset, this paper proposes a parameter design method for the LCC‐S topology that remains applicable under dual‐side‐detuned conditions. Presented the design principles of the dual‐side‐detuned circuit, and an iterative approach is employed to guide the parameter design process. It also introduced a method for selecting the rated coupling coefficient to minimize power fluctuations within the expected range. Experimental validation demonstrates that the robustness and resistance to coupling coefficient fluctuations of the proposed dual‐side‐detuned LCC‐S topology surpass those of other candidate schemes. Within a coupling variation range from 0.23 to 0.35, the maximum fluctuation rate of the output power remains below 6% while maintaining acceptable efficiency. This design has relevance to typical application scenarios. [ABSTRACT FROM AUTHOR]

Published
2024
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29. A novel LCC‐C(CL)2 compensation network for efficient magnetically coupled resonant wireless power transfer for EV charging.

Author

Li, Zhizhong, Zhang, Haonan, Zhang, Guidong, Yu, Shenglong, Zhang, Yichi, and Long, Shuqun

Subjects
WIRELESS power transmission, ELECTRIC vehicle charging stations, CHARGE transfer
Abstract

Due to the intrinsic limitations, for example, limited adjustment freedom, the traditional wireless power transfer (WPT) systems cannot maintain high efficiency under variable loading conditions. To well solve this problem, a family of general magnetically coupled resonant WPT (MCR‐WPT) compensation topologies composed of LCC‐C with an n‐stage LC structure, or LCC‐C(CL) n, is proposed in this paper. Under the guideline of the generalized structure, some existing topologies are derived for verification, with new topologies established with unique advantages. From the LCC‐C(CL) n structures, a suitable topology can be selected to achieve a desired design purpose, such as constant voltage transmission, constant current transmission, or high‐efficiency transmission. Prototype experiments and comparisons are conducted in this work, which demonstrate the effectiveness and applicability of the proposed LCC‐C(CL) n MCR‐WPT converter family and the parameter design method. Experimental results also show that the new topology can maintain high‐efficiency power transfer for a wide range of loads. Even under light loading conditions, the power transfer efficiency is 30% higher than the traditional benchmark topology. The proposed WPT approach will have wide applications for on‐road wireless electric vehicle charging. [ABSTRACT FROM AUTHOR]

Published
2024
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30. Fast FFT-Based Inference in 3D Convolutional Neural Networks

Author

Xie, Bo, Zhang, Guidong, Shen, Yongjun, Liu, Shun, Ge, Yabin, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Barolli, Leonard, editor, Xhafa, Fatos, editor, Javaid, Nadeem, editor, and Enokido, Tomoya, editor

Published
2019
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31. Intrusion Detection Model Based on GA Dimension Reduction and MEA-Elman Neural Network

Author

Zhang, Ze, Zhang, Guidong, Shen, Yongjun, Zhu, Yan, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Barolli, Leonard, editor, Xhafa, Fatos, editor, Javaid, Nadeem, editor, and Enokido, Tomoya, editor

Published
2019
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35. New Photonic Power Converters: Theories and Experimental Verification

Author

Zhang, Guidong, Huang, Zaoming, Ma, Xiaoyang, Yu, Samson Shenglong, Zhang, Bo, and Tse, Chi K.

Abstract

Photonic power converter (PPC) is a novel dc–dc converter or transformer, that uses photons as the medium to realize energy transfer. Current PPCs can only achieve dc–dc power conversion, limiting their application spectrum. To realize other types of power conversion, this study proposes ac–dc, ac–ac and dc–ac PCCs, which utilizes the combined material characteristics of light-emitting diode and photovoltaic cells. After theoretical proposition, prototypes for dc–dc, ac–dc, ac–ac, and dc–ac PPCs are built for experimental verification, and the total harmonic distortion (THD) is analyzed by power quality analyzer. The working prototypes of the four types of PPCs will find wide applications in various industries.

Published
2024
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37. A Two-Tiered Defence of Techniques to Prevent SQL Injection Attacks

Author

Zhu, Yan, Zhang, Guidong, Lai, Zhiquan, Niu, Boya, Shen, Yongjun, Kacprzyk, Janusz, Series editor, Pal, Nikhil R., Advisory editor, Bello Perez, Rafael, Advisory editor, Corchado, Emilio S., Advisory editor, Hagras, Hani, Advisory editor, Kóczy, László T., Advisory editor, Kreinovich, Vladik, Advisory editor, Lin, Chin-Teng, Advisory editor, Lu, Jie, Advisory editor, Melin, Patricia, Advisory editor, Nedjah, Nadia, Advisory editor, Nguyen, Ngoc Thanh, Advisory editor, Wang, Jun, Advisory editor, Barolli, Leonard, editor, and Enokido, Tomoya, editor

Published
2018
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48. Conclusions

Author

Zhang, Guidong, Zhang, Bo, Li, Zhong, Kacprzyk, Janusz, Series editor, Zhang, Guidong, Zhang, Bo, and Li, Zhong

Published
2018
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50. Boost-type push–pull converter with reduced switches

Author

Gu, Aiyu, Sun, Weijie, Zhang, Guidong, Chen, Sizhe, Wang, Yu, Yang, Ling, and Zhang, Yun

Abstract

This paper develops and analyses a boost-type push–pull converter with a reduced number of switches. The newly designed converter mainly consists of five diodes, two switches, two inductors, a transformer and two capacitors. By tuning the duty cycle and the transformer ratio, different voltage gains of the proposed converter can be obtained. It is notable for its electrical isolation characteristics. When compared with traditional step-up converters, the step-up module and converter module share the same switch. In addition, the control of the converter becomes easier to implement, and it has better stability and a reduced volume. It should be mentioned that the number of switches in the proposed converter is decreased but maintains the same voltage stress when compared to the traditional structure. The operating principle of proposed converter is demonstrated, which is followed by the design of the component parameters. To validate the feasibility of the proposed topology, an experimental prototype is constructed to verify its correctness and practicability of the proposed converter when compared with the conventional converter.

Published
2024
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