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Black-hole-inspired thermal trapping with graded heat-conduction metadevices

National Science Review 2023年第2期10卷 131-138页

作者： Liujun Xu Jinrong Liu Peng Jin Guoqiang Xu Jiaxin Li Xiaoping Ouyang Ying Li Cheng-Wei Qiu Jiping Huang Department of Physics State Key Laboratory of Surface Physics and Key Laboratory of Micro and Nano Photonic Structures (MOE) Fudan University Department of Electrical and Computer Engineering National University of Singapore Graduate School of China Academy of Engineering Physics School of Materials Science and Engineering Xiangtan University Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical InstrumentationZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang University International Joint Innovation Center Key Laboratory of Advanced Micro/Nano Electronic Devices and Smart Systems of Zhejiang The Electromagnetics Academy of Zhejiang University Zhejiang University

The curved space-time produced by black holes leads to the intriguing trapping *** far,metadevices have enabled analogous black holes to trap light or sound in laboratory ***,trapping heat in a conductive environment is still challenging because diffusive behaviors are *** by black holes,we construct graded heat-conduction metadevices to achieve thermal trapping,resorting to the imitated advection produced by graded thermal conductivities rather than the trivial solution of using insulation materials to confine thermal *** experimentally demonstrate thermal trapping for guiding hot spots to diffuse towards the *** heat-conduction metadevices have advantages in energy-efficient thermal regulation because the imitated advection has a similar temperature field effect to the realistic advection that is usually driven by external energy *** results also provide an insight into correlating transformation thermotics with other disciplines,such as cosmology,for emerging heat control schemes.

关键词： thermal trapping graded metadevices imitated advection

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Low-Power Envelope Detector for WSN Wake-up Receiver Applications 1

Low-Power Envelope Detector for WSN Wake-up Receiver Applica...

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1st IEEE International Conference on Design, Test and Technology of Integrated systems, DTTIS 2023

作者： Bouraoui, Mariem Neifar, Amel Barraj, Imen Masmoudi, Mohamed National Engineers School of Sfax University of Sfax Systems Integration and Emerging Energies Laboratory Electrical Engineering Department Sfax3038 Tunisia University of Gabes National Engineers School of Gabes Tunisia Prince Sattam Bin Abdulaziz University College of Computer Engineering and Sciences Department of Computer Engineering Al-Kharj11942 Saudi Arabia

ISBN: (纸本)9798350316957

This paper highlights the importance of the wake-up receiver in applications using WSN while offering a brief description of this element. In this work, the design of a low-power envelope detector for wake-up receiver applications is presented. By using RF-TSMC CMOS 0.18μm, the proposed envelope circuit is designed for 52 GHz frequency. The forward body biasing method is employed to decrease the circuit energy consumption. The proposed circuit can achieve 152MHz cut-off frequency over the operating frequency range and has power dissipation of 87.5μW under 1V. © 2023 IEEE.

关键词： CMOS integrated circuits

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A hybrid attention deep learning network for refined segmentation of cracks from shield tunnel lining images

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Journal of Rock Mechanics and Geotechnical engineering 2023年第12期15卷 3105-3117页

作者： Shuai Zhao Guokai Zhang Dongming Zhang Daoyuan Tan Hongwei Huang Department of Civil and Environmental Engineering The Hong Kong Polytechnic University999077Hong KongChina School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai200092China

This research developed a hybrid position-channel network (named PCNet) through incorporating newly designed channel and position attention modules into U-Net to alleviate the crack discontinuity problem in channel and spatial dimensions. In PCNet, the U-Net is used as a baseline to extract informative spatial and channel-wise features from shield tunnel lining crack images. A channel and a position attention module are designed and embedded after each convolution layer of U-Net to model the feature interdependencies in channel and spatial dimensions. These attention modules can make the U-Net adaptively integrate local crack features with their global dependencies. Experiments were conducted utilizing the dataset based on the images from Shanghai metro shield tunnels. The results validate the effectiveness of the designed channel and position attention modules, since they can individually increase balanced accuracy (BA) by 11.25% and 12.95%, intersection over union (IoU) by 10.79% and 11.83%, and F1 score by 9.96% and 10.63%, respectively. In comparison with the state-of-the-art models (i.e. LinkNet, PSPNet, U-Net, PANet, and Mask R–CNN) on the testing dataset, the proposed PCNet outperforms others with an improvement of BA, IoU, and F1 score owing to the implementation of the channel and position attention modules. These evaluation metrics indicate that the proposed PCNet presents refined crack segmentation with improved performance and is a practicable approach to segment shield tunnel lining cracks in field practice.

关键词： Crack segmentation Crack disjoint problem U-net Channel attention Position attention

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Dielectric Resonator Magnetoelectric Dipole Arrays with Low Cross Polarization,Backward Radiation,and Mutual Coupling for MIMO Base Station Applications

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China Communications 2024年第6期21卷 290-304页

作者： Song Simin Da Yiran Qian Bingyi Huang Xiaoyu Chen Xiaoming Li Yingsong Ahmed A.Kishk School of Information and Communications Engineering Xi’an Jiaotong UniversityXi’an 710049China Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui UniversityHefei 230039China Department of Electrical and Computer Engineering Concordia UniversityMontrealQC H3G 1M8Canada

Dielectric resonator magnetoelectric dipole(DRMED)arrays with enhanced isolation,reduced cross-polarization,and backward radiation are proposed for base station(BS)*** proposed antenna comprises an elevated dielectric resonator antenna(DRA)on a small metal plate above a sizeable common ground *** DRA is designed in its T Eδ11 mode,acting like a magnetic *** surface current excited by the differential probes flowing on the small ground plane is equivalent to an electric *** these two equivalent dipoles are orthogonal,they have the magnetoelectric dipole characteristics with reduced backward ***,the small ground planes can be treated as decoupling structures to provide a neutralization path to cancel the original coupling path.A linearly-polarized 4-element prototype array was verified experimentally in previous ***,a dual-polarized DRMED antenna is presented to construct a 2-element and 4×4 array for BS *** investigate its MIMO performance,sophisticated multi-cell scenario simulations are carried *** using the proposed dualpolarized DRMED array,the cellular system capacityis improved by 118.6%compared to a conventional DRA *** significant MIMO system improvement is mainly due to the reduced backward radiation and,therefore,reduced inter-cell *** align well with the simulations.

关键词： backward radiation dielectric resonator antennas(DRAs) isolation magnetoelectric-dipole(ME-dipole)antennas

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Preliminary Results on the Impulse Breakdown Characteristics of Natural Ester Oil and Oil-Based Nanofluid with Fe2O3 Nanoparticles

Preliminary Results on the Impulse Breakdown Characteristics...

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International Conference on Environment and electrical engineering (EEEIC)

作者： Alexandros Y. Hadjicostas Evangelos T. Staikos George D. Peppas Zacharias G. Datsios George Litsardakis Eleftheria C. Pyrgioti Ioannis F. Gonos Thomas E. Tsovilis High Voltage Laboratory School of Electrical & Computer Engineering Aristotle University of Thessaloniki Greece School of Electrical & Computer Engineering Technical University of Crete Chania Greece Laboratory of Materials for Electrotechnics School of Electrical & Computer Engineering Aristotle University of Thessaloniki Greece Electrical & Computer Engineering Department High Voltage Laboratory University of Patras Greece

ISBN: (数字)9798350355185

ISBN: (纸本)9798350355192

This study presents an experimental investigation of the impulse breakdown characteristics of natural ester oil, in its pure form, and as the base liquid for a nanofluid with Fe203 nanoparticles (0.050% w/w). A two-stage impulse voltage generator and a combination wave generator have been used to determine the distribution of the breakdown voltage and time to breakdown; a standard test-cell per IEC 60897 and a custom-made metal fixture were employed for that purpose. Experimental results are discussed with emphasis given to the response time of the iron oxide nanofluid when compared to the base liquid.

关键词： Nanoparticles Ferrites Breakdown voltage Liquids Electric breakdown Oils Statistical distributions Generators Time factors Standards

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MMAL: Multi-Modal Analytic Learning for Exemplar-Free Audio-Visual Class Incremental Tasks 24

MMAL: Multi-Modal Analytic Learning for Exemplar-Free Audio-...

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32nd ACM International Conference on Multimedia, MM 2024

作者： Yue, Xianghu Zhang, Xueyi Chen, Yiming Zhang, Chengwei Lao, Mingrui Zhuang, Huiping Qian, Xinyuan Li, Haizhou Department of Electrical and Computer and Engineering National University of Singapore Singapore Laboratory for Big Data and Decision National University of Defense Technology Hunan Changsha China School of Electronic Electrical and Communication Engineering University of the Chinese Academy of Sciences Beijing China National Key Laboratory of Information Systems Engineering National University of Defense Technology Hunan Changsha China Shien-Ming Wu School of Intelligent Engineering South China University of Technology Guangdong Guangzhou China School of Computer and Communication Engineering University of Science and Technology Beijing Beijing China Shenzhen China

ISBN: (纸本)9798400706868

Class-incremental learning poses a significant challenge under an exemplar-free constraint, leading to catastrophic forgetting and sub-par incremental accuracy. Previous attempts have focused primarily on single-modality tasks, such as image classification or audio event classification. However, in the context of Audio-Visual Class-Incremental Learning (AVCIL), the effective integration and utilization of heterogeneous modalities, with their complementary and enhancing characteristics, remains largely unexplored. To bridge this gap, we propose the Multi-Modal Analytic Learning (MMAL) framework, an exemplar-free solution for AVCIL that employs a closed-form, linear approach. To be specific, MMAL introduces a modality fusion module that re-formulates the AVCIL problem through a Recursive Least-Square (RLS) perspective. Complementing this, a Modality-Specific Knowledge Compensation (MSKC) module is designed to further alleviate the under-fitting limitation intrinsic to analytic learning by harnessing individual knowledge from audio and visual modality in tandem. Comprehensive experimental comparisons with existing methods show that our proposed MMAL demonstrates superior performance with the accuracy of 76.71%, 78.98%, and 76.19% on AVE, Kinetics-Sounds, and VGGSounds100 datasets, respectively, setting new state-of-the-art AVCIL performance. Notably, compared to those memory-based methods, our MMAL, being an exemplar-free approach, provides good data privacy and can better leverage multi-modal information for improved incremental accuracy. © 2024 ACM.

关键词： Contrastive Learning

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Pole Slipping in Droop-Based Grid-Forming Inverters

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IEEE Access 2025年 13卷 100338-100352页

作者： Negar Karimipour Hansi Wijayalath Arachchilage Amir Abiri Jahromi Behrooz Bahrani Mohammadreza F. M. Arani Department of Electrical Computer and Biomedical Engineering Toronto Metropolitan University Toronto ON Canada Department of Electrical and Computer Systems Engineering Monash University Clayton VIC Australia School of Electronic and Electrical Engineering University of Leeds Leeds U.K.

Integration of grid-forming inverter-based resources is considered as a viable solution to address the challenges associated with the dynamics of power systems with high penetration levels of inverter-based resources. Yet, various aspects of dynamic behaviour of grid-forming inverters during disturbances have remained unknown. This paper for the first time introduces the concept of pole slipping in grid forming inverters, referring to the loss of synchronism where the inverter’s internal phase angle deviates beyond 180° with respect to the grid, similar to synchronous generators losing step. It is revealed that this event in grid forming inverters can be stable or unstable. The differences between stable and unstable pole slipping are highlighted. The determining factors for the occurrence of stable and unstable pole slipping in grid forming inverters and equipment-level implications of pole slipping are identified and studied. A solution is proposed to mitigate stable and unstable pole slipping in grid-forming inverters by adjusting the operating reference power during the disturbance. The validity of the proposed concept of pole slipping in grid forming inverters and the proposed solution is tested and verified through extensive time-domain simulations and experimental results. The results verify that pole slipping is more likely to happen in high short circuit ratios (SCRs). It is revealed that unstable pole slipping does not occur at SCRs lower than 3.5. Simulation and experimental results demonstrate that a phase jump as small as 10° may lead to instability in a grid with SCRs equal or higher than 10. This is while in lower SCRs such phase jumps result in long fault recovery without causing pole slipping.

关键词： Inverters Synchronous generators Power system stability Grid forming Voltage Rotors Circuit stability Transient analysis Current limiters Stability criteria

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Energy-Efficient and Latency-Optimized Computation Offloading with Improved MOEA for Industrial Internet of Things

Energy-Efficient and Latency-Optimized Computation Offloadin...

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2024 IEEE International Conference on systems, Man, and Cybernetics, SMC 2024

作者： Zhai, Jiahui Bi, Jing Yuan, Haitao Yang, Jinhong Zhang, Jia Zhou, MengChu College of Computer Beijing University of Technology Beijing100124 China School of Automation Science and Electrical Engineering Beihang University Beijing100191 China Cssc Systems Engineering Research Institute Beijing China Southern Methodist University Dept. of Computer Science DallasTX75275 United States New Jersey Institute of Technology Dept. of Electrical and Computer Engineering NewarkNJ07102 United States

ISBN: (纸本)9781665410205

The unprecedented prosperity of the industrial Internet of Things has thoroughly facilitated the transition from traditional manufacturing towards intelligent manufacturing. In industrial environments, resource-constrained industrial equipments (IEs) often fail to meet the diverse demands of numerous compute-intensive and latency-sensitive tasks. Mobile edge computing has emerged as an innovative paradigm for lower latency and energy consumption for IEs. However, computational offloading and coordinating of multiple IEs with diverse task types and multiple edge nodes in industrial environments poses challenges. To address this challenge, we propose a multi-task approach encompassing scientific and concurrent workflow tasks to achieve energy-efficient and latency-optimized computation offloading. Furthermore, this work designs an improved Quantum Multi-objective Grey wolf optimizer with Manta ray foraging and Associative learning (QMGMA) to optimize multi-task computation offloading. Comprehensive experiments demonstrate the superior efficiency and stability of QMAGA compared to state-of-the-art algorithms in balancing latency and energy consumption. QMAGA improves average inverse generation distance and average spacing by 37% and 31% on average than multi-objective grey wolf optimizer, non-dominated sorting genetic algorithm II, and multi-objective multi-verse optimization, proving the convergence and diversity of its non-dominated solutions. © 2024 IEEE.

关键词： Smart manufacturing

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Free-electron crystals for enhanced X-ray radiation

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Light(Science & Applications) 2024年第7期13卷 1299-1309页

作者： Lee Wei Wesley Wong Xihang Shi Aviv Karnieli Jeremy Lim Suraj Kumar Sergio Carbajo Ido Kaminer Liang Jie Wong School of Electrical and Electronic Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore. Solid State Institute and Faculty of Electrical and Computer Engineering Technion–Israel Institute of TechnologyHaifa 3200003Israel. School of Electrical Engineering Fleischman Faculty of EngineeringTel Aviv UniversityTel Aviv 69978Israel Department of Applied Physics Stanford UniversityStanfordCA 94305USA. Science Mathematics and TechnologySingapore University of Technology and Design8 Somapah RoadSingapore 487372Singapore. Electrical and Computer Engineering Department UCLA420 WestwoodLos AngelesCA 90095USA. Physics and Astronomy Department UCLA475 Portola PlazaLos AngelesCA 90095USA. SLAC National Accelerator Laboratory Stanford University2575 Sand Hill RoadMenlo ParkCA 94025USA

Bremsstrahlung—the spontaneous emission of broadband radiation from free electrons that are deflected by atomic nuclei—contributes to the majority of X-rays emitted from X-ray tubes and used in applications ranging from medical imaging to semiconductor chip ***,we show that the bremsstrahlung intensity can be enhanced significantly—by more than three orders of magnitude—through shaping the electron wavefunction to periodically overlap with atoms in crystalline ***,we show how to shape the bremsstrahlung X-ray emission pattern into arbitrary angular emission profiles for purposes such as unidirectionality and ***,we find that these enhancements and shaped emission profiles cannot be attributed solely to the spatial overlap between the electron probability distribution and the atomic centers,as predicted by the paraxial and nonrecoil theory for free electron light *** work highlights an unprecedented regime of free electron light emission where electron waveshaping provides multi-dimensional control over practical radiation processes like *** results pave the way towards greater versatility in table-top X-ray sources and improved fundamental understanding of quantum electron-light interactions.

关键词： overlap attributed arbitrary

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Currency Exchange Rate Forecasting Using Support Vector Classifiers 14

Currency Exchange Rate Forecasting Using Support Vector Clas...

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14th International Conference on Information, Intelligence, systems and Applications, IISA 2023

作者： Koutsellis, Themistoklis Makarouni, Ioanna Choumas, Stylianos Ververidis, Christopher Papapolyzos, Thomas Bitsikas, Anastasios Doukas, Haris School of Electrical and Computer Engineering National Technical University of Athens Decision Support Systems Laboratory Athens Greece Hypertech Sa Athens Greece CAPITAL.GR Sa Athens Greece

ISBN: (纸本)9798350318067

Currency exchange markets are among the largest markets worldwide. Due to their decentrilised nature and the variation of the engaged stakeholders (i.e., from big funds and corporates to small enterprises and citizens), the currency exchange rate forecasting is a challenging task, crucial in decision making and democratisation of this domain. The main objective of this paper is to explore dependence patterns among various econometric time series, directly, or indirectly, related to currency exchange rate time series. Thereafter, on top of this dependence analysis, we deliver machine learning algorithms (e.g., support vector classifiers) to predict future values of currency exchange rates. Under this framework, the notions of time series autocorrelation and cross-correlation are utilised. However, both exhibit limitations because they cannot depict non-linear dependances. To tackle this caveat, we analyse the absolute values of the returns (i.e., percentage change) of the examined time series. The efficiency of the proposed procedure is demonstrated with eight currency exchange rate time series and eleven exogenous econometric time series related to the former. Finally, we trained eight support vector classifiers, one for each currency pair, all of which reached an accuracy level of approximately 80%. © 2023 IEEE.

关键词： Time series

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