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Riemann-Encircling Exceptional Points for Efficient Asymmetric Polarization-Locked Devices

Physical Review Letters 2022年第12期129卷 127401-127401页

作者： Aodong Li Weijin Chen Heng Wei Guowei Lu Andrea Alù Cheng-Wei Qiu Lin Chen Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 China Department of Electrical and Computer Engineering National University of Singapore Singapore 117583 Singapore State Key Laboratory for Mesoscopic Physics School of Physics Peking University Beijing 100871 China Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Physics Program Graduate Center City University of New York New York New York 10016 USA

Dynamically encircling exceptional points (EPs) have unveiled intriguing chiral dynamics in photonics. However, the traditional approach based on an open manifold of Hamiltonian parameter space fails to explore trajectories that pass through an infinite boundary. Here, by mapping the full parameter space onto a closed manifold of the Riemann sphere, we introduce a framework to describe encircling-EP loops. We demonstrate that an encircling trajectory crossing the north vertex can realize near-unity asymmetric transmission. An efficient gain-free, broadband asymmetric polarization-locked device is realized by mapping the encircling path onto L-shaped silicon waveguides.

关键词： PT-symmetric quantum mechanics Photonics

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Correction: Advancements in additive manufacturing for video laryngoscopes: a comprehensive scoping and technological review

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Systematic reviews 2024年第1期13卷 31页

作者： Ana Cristina Beitia Kraemer Moraes Chiara das Dores do Nascimento Everton Granemann Souza Mauricio Beitia Kraemer Mauricio Moraes Neftali Lenin Villarreal Carreno Evandro Piva Rafael Guerra Lund Pelotas Dental School Graduate Program in Dentistry Federal University of Pelotas Pelotas RS 96010‑560 Brazil. Master's Degree in Electronic and Computer Engineering Center for Social and Technological Sciences Catholic University of Pelotas Pelotas RS 96015‑560 Brazil. Faculty of Medicine São Francisco University Bragança Paulista SP 12916‑900 Brazil. Faculty of Medicine Federal University of Pelotas Pelotas RS 96010‑560 Brazil. Graduate Program in Materials Science and Engineering Technological Development Center Federal University of Pelotas Pelotas RS 96010‑610 Brazil. Pelotas Dental School Graduate Program in Dentistry Federal University of Pelotas Pelotas RS 96010‑560 Brazil. rafael.lund@***. Graduate Program in Materials Science and Engineering Technological Development Center Federal University of Pelotas Pelotas RS 96010‑610 Brazil. rafael.lund@***.

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Approximate Subtractor Operator for Low-Power Video Coding Hardware Accelerators

Approximate Subtractor Operator for Low-Power Video Coding H...

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IEEE International Conference on electronics, Circuits and Systems

作者： Rafael Ferreira Mateus Leme Marcel Correa Luciano Agostini Claudio Diniz Bruno Zatt Graduate Program on Computer Science Federal University of Pelotas (UFPel) Pelotas Brazil Graduate Program on Electronic Engineering and Computing Catholic University of Pelotas (UCPel) Pelotas Brazil

Video coding requires a massive computational effort leading to large power dissipation and energy consumption. Thus, energy efficiency becomes a significant concern especially under limited energy resources such as in mobile devices. Approximate computing is a promising technique to improve energy efficiency. Therefore, this work presents a new approximate subtractor operator to be used in video coding hardware accelerators. The proposed subtractor reduces power of a Sum of Absolute Differences (SAD) hardware accelerator on approximately 10.39% (on average of different videos) when compared to the use of the subtractor from the synthesis tool. It also presents a power reduction of 18.13% when compared to state-of-the-art approximate adder.

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Bulk-plasmon-mediated free-electron radiation beyond the conventional formation time

arXiv

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arXiv 2022年

作者： Tay, Fuyang Lin, Xiao Shi, Xihang Chen, Hongsheng Kaminer, Ido Zhang, Baile Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation ZJUHangzhou Global Science and Technology Innovation Center College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley–Curl Institute Rice University HoustonTX77005 United States International Joint Innovation Center The Electromagnetics Academy Zhejiang University Zhejiang University Haining314400 China Department of Electrical Engineering Technion-Israel Institute of Technology Haifa32000 Israel Jinhua Institute of Zhejiang University Zhejiang University Jinhua321099 China Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 637371 Singapore Centre for Disruptive Photonic Technologies Nanyang Technological University 637371 Singapore

Free-electron radiation is a fundamental photon emission process that is induced by fast-moving electrons interacting with optical media. Historically, it has been understood that, just like any other photon emission process, free-electron radiation must be constrained within a finite time interval known as the "formation time", whose concept is applicable to both Cherenkov radiation and transition radiation, the two basic mechanisms describing radiation from a bulk medium and from an interface, respectively. Here we reveal an alternative mechanism of free-electron radiation far beyond the previously defined formation time. It occurs when a fast electron crosses the interface between vacuum and a plasmonic medium supporting bulk plasmons. While emitted continuously from the crossing point on the interface — thus consistent with the features of transition radiation — the extra radiation beyond the conventional formation time is supported by a long tail of bulk plasmons following the electron’s trajectory deep into the plasmonic medium. Such a plasmonic tail mixes surface and bulk effects, and provides a sustained channel for electron-interface interaction. These results also settle the historical debate in Ferrell radiation, regarding whether it is a surface or bulk effect, from transition radiation or plasmonic oscillation. Copyright © 2022, The Authors. All rights reserved.

关键词： Plasmonics

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Performance and Optimization of Reconfigurable Intelligent Surface Aided THz Communications

arXiv

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arXiv 2020年

作者： Du, Hongyang Zhang, Jiayi Guan, Ke Niyato, Dusit Jiao, Huiying Wang, Zhiqin Kürner, Thomas The School of Computer Science and Engineering The Energy Research Institute @ NTU Interdisciplinary Graduate Program Nanyang Technological University Singapore The School of Electronic and Information Engineering Beijing Jiaotong University Beijing100044 China The State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing100044 China The School of Computer Science and Engineering Nanyang Technological University Singapore China Academy of Information and Communications Technology Beijing100191 China Technische Universität Braunschweig Brunswick38106 Germany

TeraHertz (THz) communications can satisfy the high data rate demand with massive bandwidth. However, severe path attenuation and hardware imperfection greatly alleviate its performance. Therefore, we utilize the reconfigurable intelligent surface (RIS) technology and investigate the RIS-aided THz communications. We first prove that the small-scale amplitude fading of THz signals can be accurately modeled by the fluctuating two-ray distribution based on two THz signal measurement experiments conducted in a variety of different scenarios. To optimize the phase-shifts at the RIS elements, we propose a novel swarm intelligence-based method that does not require full channel estimation. We then derive exact statistical characterizations of end-to-end signal-to-noise plus distortion ratio (SNDR) and signal-to-noise ratio (SNR). Moreover, we present asymptotic analysis to obtain more insights when the SNDR or the number of RIS's elements is high. Finally, we derive analytical expressions for the outage probability and ergodic capacity. The tight upper bounds of ergodic capacity for both ideal and non-ideal radio frequency chains are obtained. It is interesting to find that increasing the number of RIS's elements can significantly improve the THz communications system performance. For example, the ergodic capacity can increase up to 25% when the number of elements increases from 40 to 80, which incurs only insignificant costs to the system. © 2020, CC BY.

关键词： Signal to noise ratio

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Study on estimating electric potential in space between parallel electrodes

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IEEJ Transactions on Fundamentals and Materials 2018年第8期138卷 400-407页

作者： Tsujita, Atsushi Ohchi, Masashi Wakimoto, Takayuki Master's Program in Electrical Electronics and Computer Engineering Graduate School of Engineering Chiba Institute of Technology 2-17-1 Tudanuma Narashino275-0016 Japan Department of Electrical and Electronic Engineering Faculty of Engineering Chiba Institute of Technology 2-17-1 Tudanuma Narashino275-0016 Japan

We have been studying on estimating distribution of permittivity between measurement electrodes using capacitance and electric potential. Two arc electrodes were separated by long distance and there electrodes were surrounded by additional electrodes respectively. In past research work, we carried out numerical electric analysis for calculating the capacitance and electric potential using Finite Element Method(FEM) and compared with experimental and numerical results. The capacitance values were almost agree with experimental and numerical results. However, the electric potential values were different between experimental and numerical results in conventional studies. In this paper, we proposed an equivalent circuit including the stray capacity and measurement method for capacitance, the electric potential in space between long distance electrodes was estimeded. © 2018 The Institute of Electrical Engineers of Japan.

关键词： Electric potential

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Numerical electric field analysis of capacitance and potential in space for estimation of permittivity distribution

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IEEJ Transactions on Fundamentals and Materials 2018年第4期138卷 119-126页

作者： Yamanobe, Hiroshi Ohchi, Masashi Master's Program in Electrical Electronics and Computer Engineering Graduate School of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino275-0016 Japan Department of Electrical and Electronic Engineering Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino275-0016 Japan

We have been studying on measuring capacitance and potential using long distance electrode for estimating a permittivity distribution. The estimating method of permittivity distribution was proposed using Finite Element Method (FEM) and Genetic Algorithm (GA). However, the measurement accuracy was not reviewed. In this paper, we carried out numerical analysis using FEM in case of change of diameter, position and permittivity of a rod of dielectric and discussed the measurement accuracy of capacitance and potential. © 2018 The Institute of Electrical Engineers of Japan.

关键词： Finite element method

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Corrigendum to "Novel model of multiple sclerosis induced by EBV-like virus generate a unique B cell population" [Journal of Neuroimmunology volume 394 (2024) 578408]

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Journal of neuroimmunology 2025年 404卷 578625页

作者： J L Deffenbaugh K-J Jung S P Murphy Y Liu C N Rau C Petersen-Cherubini P L Collins D Chung A E Lovett-Racke Department of Microbial Infection & Immunity The Ohio State University Wexner Medical Center USA. Department of Computer Science and Engineering The Ohio State University USA. Department of Microbial Infection & Immunity The Ohio State University Wexner Medical Center USA Neuroscience Graduate Program The Ohio State University USA. Department of Biomedical Informatics The Ohio State University Wexner Medical Center USA Pelotonia Institute for Immuno-Oncology The Ohio State University Wexner Medical Center USA. Department of Neuroscience The Ohio State University Wexner Medical Center USA. Electronic address: amylovettracke@***.

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Considerations for the development of LMR-based optical fiber sensors for gas sensing applications

Considerations for the development of LMR-based optical fibe...

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Bragg Gratings, Photosensitivity and Poling in Glass Waveguides and Materials, BGPPM 2018

作者： Dreyer, Uilian José Ozcariz, Aritz Zubiate, Pablo Martelli, Cicero da Silva, Jean C.C. Zamarreño, Carlos Ruiz Graduate Program in Electrical and Computer Engineering Federal University of Technology - Paraná Curitiba80230-901 Brazil Electric and Electronic Engineering Department Public University of Navarra Campus Arrosadia Pamplona31006 Spain

This work presents a preliminary study of a LMR-based gas sensor. Results of the device subjected to annealing process show a stable and repetitive response that is required for the utilization in gas sensing applicat... 详细信息

ISBN: (纸本)9781943580439

关键词： Gas detectors

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Fast HEVC Transrating using Random Forests

Fast HEVC Transrating using Random Forests

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IEEE Visual Communications and Image Processing (VCIP)

作者： Mateus Grellert Tiago Oliveira Carlos Rafael Duarte Luis A. da Silva Cruz Graduate Program in Electronic and Computer Engineering Catholic University of Pelotas Brazil

ISBN: (纸本)9781538644591;9781538644584

This article describes a fast transrating solution for HEVC based on classification and machine learning techniques. Two classifiers are trained to predict the range of CTU quadtree depths that will be searched to find the best CTU partitioning. Three approaches are proposed for reducing the number of features used by the classifiers, two based on feature selection, and one based on feature transformation using autoencoders. A full transrating framework based on x265 is built for model training and evaluation. Experimental results using the x265 encoder show that an average 41.81% computational complexity reduction can be achieved at the cost of a tolerable 0.29% Bjontegaard-Delta bitrate, outperforming competing methods.

关键词： Feature extraction Training Bit rate Streaming media Transcoding Upper bound

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