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SSRN 2024年

作者： Lv, Pengtao Zhang, Qinghui Guan, Zhenhan Deveci, Muhammet Shi, Lei Zhong, Kaiyang Wang, Jingping Xu, Heliang Zhang, Yana Ministry of Education Henan Zhengzhou450001 China Henan Key Laboratory of Grain Photoelectric Detection and Control Henan University of Technology Henan Zhengzhou450001 China Henan Grain Big Data Analysis and Application Engineering Research Center Henan University of Technology Henan Zhengzhou450001 China The Bartlett School of Sustainable Construction University College London LondonWC1E 6BT United Kingdom Department of Industrial Engineering Turkish Naval Academy National Defence University Tuzla Istanbul4940 Turkey State Key Laboratory of Media Convergence and Communication Communication University of China Beijing China Ministry of Education Key Laboratory for Intelligent Analysis and Security Governance of Ethnic Languages Minzu University of China Beijing100081 China Southwestern University of Finance and Economics China

News recommender system is an important method of helping readers identify interesting stories. Although human behaviors exhibit sequential patterns, most current studies on news recommendations ignore the influence of reading sequences. Leveraging sequential patterns in news recommendation is, however, very challenging, as the capture of reading behavior sequence at the individual level may be impossible due to severity of sparsity in the field of news. To address this challenge, we proposed a group-sequence-aware graph model (GSGM) to learn representative reading sequences of groups instead of individuals, where groups are viewed as latent variables and automatically learnt from users' reading behaviours. Besides, when readers select different groups, they are likely to have distinct reading preferences. This finding is used to learn group-dependent personal reading preferences in GSGM. A wide range of experiments are conducted to verify the efficiency and effectiveness of the GSGM on real datasets. Experimental results demonstrate that GSGM outperforms the state-of-the-art competing methods. © 2024, The Authors. All rights reserved.

关键词： Recommender systems

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A Doubly-Curved Piezoelectric Composite with 1–3 Connectivity for Underwater Transducer Applications

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IOP Conference Series: Materials Science and engineering 2018年第1期317卷

作者： Yanjun Zhang Likun Wang Lei Qin Qingwei Liao Chao Zhong Beijing Key Laboratory for Sensor Beijing Information Science & Technology University Beijing China Beijing Key Laboratory for Optoelectronic Measurement Technology Beijing Information Science & Technology University Beijing 100192 China Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science and Technology University Beijing 100192 China School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing China

Aim to increase the horizontal and vertical beam width of the high frequency transducer simultaneously, we present a doubly-curved 1-3 piezoelectric composite element. It consists of 54% piezoelectric ceramic volume fraction and two phases polymer matrix. The finite element analysis (FEA) is used to evaluate the dynamic response of composite. Electroacoustic response in water was measured for the doubly-curved composite being considered as underwater transducer. An underwater transducer was fabricated using the doubly-curved 1-3 piezoelectric composite element. The -3 dB full angle beam width of transducer is approximately 106° and 36° in the horizontal and vertical plane respectively. Both the FEA simulations and experimental results show the potential of a broad covered area of the composite transducer in underwater environment.

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Commensurate and Incommensurate Chern Insulators in Magic-angle Bilayer Graphene

arXiv

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arXiv 2024年

作者： Zhang, Zaizhe Yang, Jingxin Xie, Bo Feng, Zuo Zhang, Shu Watanabe, Kenji Taniguchi, Takashi Yang, Xiaoxia Dai, Qing Liu, Tao Liu, Donghua Liu, Kaihui Song, Zhida Liu, Jianpeng Lu, Xiaobo International Center for Quantum Materials School of Physics Peking University Beijing100871 China National Engineering Research Center of Electromagnetic Radiation Control Materials University of Electronic Science and Technology of China Chengdu611731 China School of Physical Science and Technology ShanghaiTech University Shanghai201210 China State Key Laboratory for Mesoscopic Physics Frontiers Science Centre for Nano-optoelectronics School of Physics Peking University Beijing100871 China CAS Key Laboratory of Nanophotonic Materials and Devices CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology Beijing100871 China Research Center for Electronic and Optical Materials National Institute of Material Sciences 1-1 Namiki Tsukuba305-0044 Japan Research Center for Materials Nanoarchitectonics National Institute of Material Sciences 1-1 Namiki Tsukuba305-0044 Japan School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai200240 China School of Materials and Energy University of Electronic Science and Technology of China Chengdu611731 China Collaborative Innovation Center of Quantum Matter Beijing100871 China Hefei National Laboratory Hefei230088 China

The interplay between strong electron-electron interaction and symmetry breaking can have profound influence on the topological properties of materials1–4. In magic angle twisted bilayer graphene (MATBG), the flat band with a single SU(4) flavor associated with the spin and valley degrees of freedom gains non-zero Chern number when C2z symmetry or C2zT symmetry is broken. Electron-electron interaction can further lift the SU(4) degeneracy, leading to the Chern insulator states5–14. Here we report a complete sequence of zero-field Chern insulators at all odd integer fillings (ν = ±1, ±3) with different chirality (C = 1 or -1) in hBN aligned MATBG which structurally breaks C2z symmetry. The Chern states at hole fillings (v = -1, -3), which are firstly observed in this work, host an opposite chirality compared with the electron filling scenario. By slightly doping the v = ±3 states, we have observed new correlated insulating states at incommensurate moiré fillings which is highly suggested to be intrinsic Wigner crystals according to our theoretical calculations. Remarkably, we have observed prominent Streda-formula violation around v = -3 state. By doping the Chern gap at v = -3 with notable number of electrons at finite magnetic field, the Hall resistance Ryx robustly quantizes to ~ h/e2 whereas longitudinal resistance Rxx vanishes, indicating that the chemical potential is pinned within a Chern gap, forming an incommensurate Chern insulator. By providing the first experimental observation of zero-field Chern insulators in the flat valence band, our work fills up the overall topological framework of MATBG with broken C2z symmetry. Our findings also demonstrate that doped topological flat band is an ideal platform to investigate exotic incommensurate correlated topological states. © 2024, CC BY-NC-SA.

关键词： Degrees of freedom (mechanics)

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Forest Fire Smoke Recognition Based on Multiple Feature Fusion

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IOP Conference Series: Materials Science and engineering 2018年第1期435卷

作者： Chang Lu Mingqi Lu Xiaobo Lu Min Cai Xiaoqiang Feng School of Software Engineering University of Science and Technology of China Hefei Anhui 230026 China School of Automation Southeast University Nanjing 210096 China Key Laboratory of Measurement and Control of CSE Ministry of Education Southeast University Nanjing 210096 China Enbo Technology Company Limited Nanjing 210022 China

In order to discover the forest fire at the early stage, the video based fire smoke detection system should be developed. Three static features and three dynamic features are selected to recognize the fire smoke through the analysis of forest monitoring video. To solve the fusion problem of different features, a cascade classifier based on BP neutral network is designed. Each feature vector would be assigned a classifier as the first stage of the cascaded classifier. The output of the first level of the classifier used as the input of the second level of the classifier. The weight for each feature that given by the trainer is more scientific. The result of the experiments show that the cascade classifier has better performance compared to the single BP neural network.

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Moving Target Detection Algorithm for Forest Fire Smoke Recognition with Improved ViBe

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Journal of Physics: Conference Series 2018年第1期1069卷

作者： Chang Lu Yichao Cao Xiaobo Lu Min Cai Xiaoqiang Feng School of Software Engineering University of Science and Technology of China Hefei Anhui 230026 China School of Automation Southeast University Nanjing 210096 China Key Laboratory of Measurement and Control of CSE Ministry of Education Southeast University Nanjing 210096 China Enbo Technology Company Limited Nanjing 210022 China

In order to discover the forest fire at the early stage, the video based fire smoke detection system should be developed. This paper proposes an improved ViBe algorithm to overcome the drawbacks of ViBe which is widely used in forest fire smoke recognition. To make the algorithm faster, the improved ViBe algorithm introduces a switch variable to control the model updating every 2 frames. Also, the new ViBe algorithm contains a method to detect if the scene is changing, and upon finding the changing, a fast updating strategy would be used to increase the adaptive ability. The experiments are done from 2 aspects, to test the time consuming and adaptive ability of the improved algorithm. The experiments results show that the improved ViBe algorithm has better performance compared to ViBe algorithm and GMM algorithm, and can detect the forest fire smoke accurately in different conditions.

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Intelligent embedded sensor based accident detection system and prevention system

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AIP Conference Proceedings 2022年第1期2519卷

作者： T. Dineshkumar R. Puviarasi K. Radhika T. Mangayarkarasi 1Department of Electronics and Communication Engineering Kongunadu College of Engineering and Technology Namakkal-Trichy Main Road Thottiam Tamil Nadu India 2Department of Electronics and Communication Engineering Saveetha School of Engineering Saveetha Institute of Medical and Technical Sciences Thandalam Tamil Nadu India 3Department of Electronics and Communication Engineering Geethanjali Institute of Science and Technology Nellore Andhra Pradesh India 4Department of Instrumentation and Control Engineering Sri Sairam Engineering College Chennai Tamil Nadu India

Many accidents now take place due to over-speed, drowsiness and drunken drivers. Statistics show that every four minutes people die in 2017 because of traffic crashes and thousands of accidents in India, which are higher in numbers than any other accidents, where people have died. But in the case of rescue indicators their lives may have been spared. We are also going to incorporate our thoughts on steps to mitigate the crash and precautionary measures. This proposal immediately identifies the precise location of the crash by GPS and allows GSM to transmit the data to the nearest rescue car, the police department and the individual’s family members. Accident can be detected by the accelerometer sensor and accident magnitude can be detected by the tilt sensor. The tilt angle of the chassis can be monitored. The driver’s sleepiness can be detected with a DMD. The driver’s somnolence is sensed and the driver is alerted by alarm by calculating the percentage of eyelid closing over the period. Through this tool, the speed of a car can be measured, who is responsible for the crash and the direction of GPS can be seen with the mobile theft detection program. Both data can be analyzed using the sensor value in a microcontroller and sent to the cloud site. The main benefits of the device are cost efficient, stable and victim-friendly, fast savings in energy usage, greater precision, time efficiency and the risk of human error are reduced.

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Cascade of pressure-driven phase transitions in the topological nodal-line superconductor PbTaSe2

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Physical Review B 2022年第6期106卷 L060501-L060501页

作者： Tahir Murtaza Haiyang Yang Jiajia Feng Yi Shen Yongheng Ge Yi Liu Chunqiang Xu Wenhe Jiao Yaokang Lv Christopher J. Ridley Craig L. Bull Pabitra K. Biswas Raman Sankar Wei Zhou Bin Qian Xuefan Jiang Zhenjie Feng Yonghui Zhou Ziming Zhu Zhaorong Yang Xiaofeng Xu Key Laboratory of Quantum Precision Measurement of Zhejiang Province Department of Applied Physics Zhejiang University of Technology Hangzhou 310023 China College of Information Engineering Zhejiang University of Technology Hangzhou 310023 China Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory Chinese Academy of Sciences Hefei 10 230031 China School of Physics and Key Laboratory of MEMS of the Ministry of Education Southeast University Nanjing 211189 China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha 410081 China College of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 China ISIS Pulsed Neutron and Muon Source STFC Rutherford Appleton Laboratory Harwell Campus Didcot Oxfordshire OX11 0QX United Kingdom School of Chemistry University of Edinburgh David Brewster Road Edinburgh EH9 3FJ United Kingdom Institute of Physics Academia Sinica Nankang Taipei 11529 Taiwan Department of Physics Changshu Institute of Technology Changshu 215500 China Materials Genome Institute Shanghai University Shanghai 200444 China

We report a succession of pressure-tuned structural transitions in the topological nodal-line superconductor PbTaSe2, evidenced from synchrotron x-ray diffraction, elastic neutron scattering, Raman spectroscopy, and electrical transport measurements up to 56 GPa, accompanied by first-principles calculations to uncover the evolution of the underlying electronic structure. In contrast to the previously proposed small shift of the Pb Wyckoff coordinate in the sub-GPa regime, our study reveals that it is rather a transition from P6¯m2 (α phase) to P63mc (β phase), subsequently followed by a transition to P6/mmm (γ phase) at ∼7.5 GPa and to Pmmm (δ phase) at ∼44 GPa. In addition, the first-principles calculations unambiguously demonstrate the multiple types of topological fermions associated with these different pressure-driven structures. Collectively, our results not only present the intriguing structural transitions in this topological PbTaSe2 superconductor, they also provide the impetus to study topological phase transitions and their physical consequences in a broader class of topological materials.

关键词： Phase transitions by order Superconducting phase transition Superconductivity Topological superconductors

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Entanglement filter with Rydberg atoms

arXiv

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arXiv 2022年

作者： Ye, Gen-Sheng Xu, Biao Chang, Yue Shi, Shuai Shi, Tao Li, Lin MOE Key Laboratory of Fundamental Physical Quantities Measurement Hubei Key Laboratory of Gravitation and Quantum Physics PGMF Institute for Quantum Science and Engineering School of Physics Huazhong University of Science and Technology Wuhan430074 China Beijing Automation Control Equipment Institute Beijing100074 China Quantum Technology R&D Center of China Aerospace Science and Industry Corporation Beijing10019 China Institute of Theoretical Physics Chinese Academy of Sciences P.O. Box 2735 Beijing100190 China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing100049 China

Devices capable of deterministically manipulating the photonic entanglement are of paramount importance, since photons are the ideal messengers for quantum information. Here, we report a Rydberg-atom-based entanglement filter that preserves the desired photonic entangled state and deterministically blocks the transmission of the unwanted ones. Photonic entanglement with near-unity fidelity can be extracted from an input state with an arbitrarily low initial fidelity. The protocol is inherently robust, and succeeds both in the Rydberg blockade regime and in the interaction-induced dissipation regime. Such an entanglement filter opens new routes toward scalable photonic quantum information processing with multiple ensembles of Rydberg atoms. © 2022, CC BY.

关键词： Atoms

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Master equations and quantum trajectories for squeezed wave packets

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Physical Review A 2022年第2期105卷 023721-023721页

作者： Jonathan A. Gross Ben Q. Baragiola T. M. Stace Joshua Combes Institut Quantique Université de Sherbrooke Sherbrooke Quebec Canada J1K 2R1 Center for Quantum Information and Control University of New Mexico Albuquerque New Mexico 87131-0001 USA Yukawa Institute for Theoretical Physics Kyoto University Kitashirakawa Oiwakecho Sakyo-ku Kyoto 606-8502 Japan Centre for Quantum Computation and Communication Technology School of Science RMIT University Melbourne Victoria 3000 Australia ARC Centre for Engineered Quantum System Department of Physics University of Queensland Brisbane Queensland 4072 Australia Department of Electrical Computer and Energy Engineering University of Colorado Boulder Boulder Colorado 80309 USA

The interaction between matter and squeezed light has mostly been treated within the approximation that the field-correlation time is small. Methods for treating squeezed light with more general correlations currently involve explicitly modeling the systems producing the light. We develop a general purpose input-output theory for a particular form of narrowband squeezed light, a squeezed wave-packet mode, that only concerns the statistics of the squeezed field and the shape of the wave packet. This formalism allows us to derive the input-output relations and the master equation. We also consider detecting the scattered field using photon counting and homodyne measurements, which necessitates the derivation of the stochastic master equation. The non-Markovian nature of the field manifests itself in the master equation as a coupled hierarchy of equations. We illustrate these with consequences for the decay and resonance fluorescence of two-level atoms in the presence of such fields.

关键词： Open quantum systems Squeezing of quantum noise Stochastic processes

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Preface

EAI/Springer Innovations in Communication and Computing

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EAI/Springer Innovations in communication and Computing 2021年 vii-viii页

作者： Srivastava, Smriti Khari, Manju Crespo, Ruben Gonzalez Chaudhary, Gopal Arora, Parul Instrumentation and Control Engineering Netaji Subhas University of Technology New Delhi Delhi India Department of Computer Science and Technology Universidad Internacional de La Rioja Logroño La Rioja Spain Department of Electronics and Communication Engineering Jaypee Institute of Information Technology Noida India School of Computer and Systems Sciences Jawaharlal Nehru University New Delhi Delhi India Department of Electronics and Communication Engineering Bharati Vidyapeeth’s College of Engineering New Delhi Delhi India

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