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303 results on '"Zhou, Wenzhe"'

2. Janus monolayer TaNF: a new ferrovalley material with large valley splitting and tunable magnetic properties

Author

Zheng, Guibo, Qu, Shuixian, Zhou, Wenzhe, and Ouyang, Fangping

Subjects
Condensed Matter - Materials Science
Abstract

Materials with large intrinsic valley splitting and high Curie temperature are a huge advantage for studying valleytronics and practical applications. In this work, using first-principles calculations, a new Janus TaNF monolayer is predicted to exhibit excellent piezoelectric properties and intrinsic valley splitting, resulting from the spontaneous spin polarization, the spatial inversion symmetry breaking and strong spin-orbit coupling (SOC). TaNF is also a potential two-dimensional (2D) magnetic material due to its high Curie temperature and huge magnetic anisotropy energy. The effective control of the band gap of TaNF can be achieved by biaxial strain, which can transform TaNF monolayer from semiconductor to semi-metal. The magnitude of valley splitting at the CBM can be effectively tuned by biaxial strain due to the changes of orbital composition at the valleys. The magnetic anisotropy energy (MAE) can be manipulated by changing the energy and occupation (unoccupation) states of d orbital compositions through biaxial strain. In addition, Curie temperature reaches 373 K under only -3% biaxial strain, indicating that Janus TaNF monolayer can be used at high temperatures for spintronic and valleytronic devices.

Published
2023

15. Supply Side Reform of Tourism in Ethnic Areas Empowers Common Wealth--The Perspective of Tourism Talent Resources

Author

Zhou Wenzhe

Subjects
bcc model, malmquist model, granger causality test, regression analysis, tourism talent resources, 68t05, Mathematics, QA1-939
Abstract

This paper conducts a comprehensive analysis of the types of tourism resources in ethnic regions and develops a framework for tourism supply-side reform in these areas, emphasizing the role of tourism talent resources. Utilizing the BCC and Malmquist models of Data Envelopment Analysis (DEA), this study measures the technical efficiency, pure technical efficiency, scale efficiency, and total factor productivity of selected ethnic regions from 2006 to 2015. Employing panel data, the study examines the current status and trends of human resources and tourism economic growth, using regression analysis and the Granger causality test to investigate their relationship. The findings reveal a strong correlation coefficient of 0.93 between the number of tourism employees and tourism economic growth in Ethnic Group A over the study period. The regression significance level is 0.000, indicating a probability less than 0.05, which confirms a positive correlation between the level of tourism human resources and regional tourism supply-side reforms that enhance collective wealth. This research contributes a novel perspective to the discourse on high-quality tourism development and regional economic growth.

Published
2024
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19. Cable-Suspended Cooperative Transportation Control with Multi-unmanned Helicopters

Author

Su, Zikang, Zhou, Wenzhe, Liang, Xiao, Wang, Honglun, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Wu, Meiping, editor, Niu, Yifeng, editor, Gu, Mancang, editor, and Cheng, Jin, editor

Published
2022
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24. Viewpoint Selection for Photographing Architectures

Author

He, Jingwu, Wang, Linbo, Zhou, Wenzhe, Zhang, Hongjie, Cui, Xiufen, and Guo, Yanwen

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

This paper studies the problem of how to choose good viewpoints for taking photographs of architectures. We achieve this by learning from professional photographs of world famous landmarks that are available on the Internet. Unlike previous efforts devoted to photo quality assessment which mainly rely on 2D image features, we show in this paper combining 2D image features extracted from images with 3D geometric features computed on the 3D models can result in more reliable evaluation of viewpoint quality. Specifically, we collect a set of photographs for each of 15 world famous architectures as well as their 3D models from the Internet. Viewpoint recovery for images is carried out through an image-model registration process, after which a newly proposed viewpoint clustering strategy is exploited to validate users' viewpoint preferences when photographing landmarks. Finally, we extract a number of 2D and 3D features for each image based on multiple visual and geometric cues and perform viewpoint recommendation by learning from both 2D and 3D features using a specifically designed SVM-2K multi-view learner, achieving superior performance over using solely 2D or 3D features. We show the effectiveness of the proposed approach through extensive experiments. The experiments also demonstrate that our system can be used to recommend viewpoints for rendering textured 3D models of buildings for the use of architectural design, in addition to viewpoint evaluation of photographs and recommendation of viewpoints for photographing architectures in practice.

Published
2017

35. Room-temperature ferromagnetism and half-metallicity in monolayer orthorhombic CrS2.

Author

Lei, Bocheng, Li, Aolin, Zhou, Wenzhe, Wang, Yunpeng, Xiong, Wei, Chen, Yu, and Ouyang, Fangping

Abstract

Two-dimensional materials with high-temperature ferromagnetism and half-metallicity have the latest applications in spintronic devices. Based on first-principles calculations, we have investigated a novel two-dimensional CrS2 phase with an orthorhombic lattice. Our results suggest that it is stable in dynamics, thermodynamics, and mechanics. The ground state of monolayer orthorhombic CrS2 is both ferromagnetic and half-metallic, with a high Curie temperature of 895 K and a large spin-flipping gap on values of 0.804 eV. This room-temperature ferromagnetism and half-metallicity can maintain stability against a strong biaxial strain ranging from −5% to 5%. Meanwhile, increasing strain can significantly maintain the out-of-plane magnetic anisotropy. A density of states analysis, together with the orbital-resolved magnetic anisotropy energy, has revealed that the strain-enhanced MAE is highly related to the 3d-orbital splitting of Cr atoms. Our results suggest the monolayer orthorhombic CrS2 is an ideal candidate for future spintronics. [ABSTRACT FROM AUTHOR]

Published
2024
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47. An investigation into MAC layer frame clustering for wirelass LAN intrusion detection

Author

Zhou, Wenzhe

Subjects
004.6
Abstract

The proliferation of wireless networks has today made security a major concern in the design and operation of these networks. The most popular wireless local area networks (WLANs) are those confonning to the IEEE 802.11 WLAN standards. However, research has shown that there are many vulnerabilities that exist in the wireless MAC layer of these networks that provide opportunities for malicious hackers. Identification of~ttacks occurring inside WLANs is therefore critical to their future developme.nt. This thesis aims at developing a novel MAC frame clustering scheme to solve this problem. This approach is based on the observation that when active events occurs in wireless networks, for example, scanning, joining, and attacking, the management traffic pattern in the MAC layer will be impacted. By analyzing these impacts, MAC layer attacks can be observed and recognized. The methodology involved in this research is machine learning, and a major contribution ofthe work is the classification of attack patterns through observation ofmanagement traffic clusters. The work firstly clusters the MAC management frames into groups which represent corresponding events. For each specific cluster, or event, there are unique patterns. Throug];1/recognizing the patterns of the cluster, attacking clusters can be classified into known categories. The thesis proposes the· above theory and applies it to a MAC layer Intrusion Detection System (IDS) for 802.11 Wireless LANs. This is the first time that a MAC layer IDS has been based on this technique. The IDS consists of six functions: a Traffic Filtration Function (TFF), a Management Traffic Clustering Function (MTCF), an Information Filtration Function (IFF), a First Level Classification (FLC), a Cluster Infonnation Management Function (CIMF) and a Second Level Classification (SLC). The TFF filters the MAC layer management frames and certain information from the filtered frames will be stored in the IFF. The MTCF then clusters the rest of the management frames. A novel clustering algorithm based on a sliding window approach is developed for the MTCF. A two-level classification structure is designed to recognize the cluster types. This two-level structure ensures that the IDS is able to detect unknown pattern attacks and helps decrease system false alarms. The FLC decides whether a cluster represents an abnonnal event based on the content value of the cluster (CCV) and beacon infonnation. When there is an abnonnal event, theSLC is then executed in order to determine the category of the attack according to known patterns. The work has analyzed a variety of 802.11 WLAN MAC layer active attacks and selected thirteen features for classifying the clusters. Support Vector Machine is used as the classification approach. Data captured from the real network test bed are tested on the IDS and the results show high accuracy of detection. The work presented in this thesis is applied in the 802.11 WLANs, however the underlying principles can be applIed to other wireless networks.

Published
2006

48. Changes in the photoluminescence of ultra-weak interlayer coupled MoSe2/PbI2 van der Waals heterostructures

Author

Wu, Di, primary, Li, Junzi, additional, Hao, Qiaoyan, additional, Zhou, Wenzhe, additional, Wang, Zhuo, additional, Liu, Jidong, additional, Tu, Yudi, additional, Jiang, Junjie, additional, Qi, Dianyu, additional, Li, Peng, additional, Wang, Zixuan, additional, Gan, Haibo, additional, Hong, Guo, additional, Liu, Fei, additional, He, Tingchao, additional, Ouyang, Fangping, additional, and Zhang, Wenjing, additional

Published
2023
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