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Chip-scale spontaneous quasi-phase matched second harmonic generation in a micro-racetrack resonator

Science China(Physics,Mechanics & Astronomy) 2023年第8期66卷 66-74页

作者： Tingge Yuan Jiangwei Wu Yi'an Liu Xiongshuo Yan Haowei Jiang Hao Li Zhaokang Liang Qiang Lin Yuping Chen Xianfeng Chen State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and Astronomy.Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of Light Manipulations and Applications Shandong Normal UniversityJinan 250358China Department of Electrical and Computer Engineering University of RochesterNew York 14627USA

In this paper,we demonstrate efficient spontaneous quasi-phase matched(SQPM)second harmonic generation(SHG)in a microracetrack resonator on X-cut thin film lithium *** approach does not involve poling,but exploits the anisotropy of the crystals to allow the phase-matching condition to be fulfilled spontaneously as the TE-polarized light circulates in a specifically designed racetrack *** experiment,normalized on-chip conversion efficiencies of 1.01×10-4/W and 0.43×10-4/W are achieved by 37th-order and 111th-order SQPM,*** configurable SQPM will benefit the application of nonlinear frequency conversion and quantum source generation in chip-scale integrated photonics compatible with standard CMOS fabrication processes.

关键词： lithium niobate on insulator quasi-phase matching second harmonic generation

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Physics-Informed Neural Networks for Privacy-Preserving Model Sharing in Power systems

Physics-Informed Neural Networks for Privacy-Preserving Mode...

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IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT Europe)

作者： Ilayda Canyakmaz Can Berk Saner Antonios Varvitsiotis Engineering Systems and Design Pillar Singapore University of Technology and Design Singapore Electrical and Computer Engineering Department National University of Singapore Singapore

ISBN: (数字)9798350390421

ISBN: (纸本)9798350390438

Data privacy concerns in the power systems sector significantly complicate the sharing and integration of sensitive operational data among various independent entities. This challenge is particularly pronounced when developing system-wide mathematical models, as the reluctance to share sub-system models parametrized by sensitive data hinders effective system analysis and decision-making. To address this issue, this work introduces the application of Physics-Informed Neural Networks (PINNs) to develop surrogate models that accurately replicate power system dynamics without exposing sensitive data, enabling privacy-preserving model sharing. By embedding physical laws into the training process, PINNs utilize both available data and inherent system physics, making them particularly suitable for modeling complex dynamics. We propose a framework for model development, including dataset generation and integration of the physics knowledge during PINN training. As a proof-of-concept, we apply this framework to a simplified Single Machine Infinite Bus (SMIB) system. Case studies demonstrate that the trained PINN model closely follows ground-truth dynamics and consistently achieves higher accuracy compared to generic neural networks, highlighting the potential for accurate, privacy-preserving model sharing and system-wide dynamic simulations in power systems.

关键词： Training Accuracy Torque System dynamics Power system dynamics Europe Voltage Data models Mathematical models Physics

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Operational strategies for a photovoltaic-thermal system integrated with an electric air-to-water heat pump 3

Operational strategies for a photovoltaic-thermal system int...

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3rd International Conference on Energy Transition in the Mediterranean Area, SyNERGY MED 2024

作者： Russo, Giuseppe Olympios, Andreas V. Pandey, Chandan Buonomano, Annamaria Markides, Christos N. University of Naples Federico II Department of Industrial Engineering Naples80125 Italy Laboratory Sargent Centre for Process Systems Engineering Department of Chemical Engineering London United Kingdom University of Cyprus PV Technology Laboratory Department of Electrical and Computer Engineering Nicosia Cyprus PHAETHON Centre of Excellence for Intelligent Efficient and Sustainable Energy Solutions Nicosia Cyprus

ISBN: (纸本)9798350375923

In this study, operational strategies are investigated for an air-based photovoltaic-thermal (PV-T) system integrated with a domestic air-to-water heat pump. The PV-T system is used to simultaneously generate electricity and heat ambient air, which serves as the heat source for the heat pump. By utilising a variable-speed fan to regulate airflow, the PV-T system outlet temperature is adjusted, and the focus is on how different outlet temperatures impact the PVT system electrical and thermal efficiency, heat pump performance, and overall electricity requirements for heating. The performance of the integrated system is assessed for a case study of a household application in north Italy. The optimal PV-T outlet temperature is found to be between 30 - 35 °C, resulting in only 5% less electricity production than an equivalent PV system with equal nominal electricity capacity, while reducing overall electricity required for heating by over 15% compared to PV-integrated heat pumps. © 2024 IEEE.

关键词： Photovoltaics

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False Sense of Security on Protected Wi-Fi Networks

arXiv

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arXiv 2025年

作者： Lim, Yong Zhi Rahman, Hazmei Bin Abdul Sikdar, Biplab Information Systems Technology and Design Singapore University of Technology and Design Singapore Department of Electrical & Computer Engineering National University of Singapore Singapore

The Wi-Fi technology (IEEE 802.11) was introduced in 1997. With the increasing use and deployment of such networks, their security has also attracted considerable attention. Current Wi-Fi networks use WPA2 (Wi-Fi Protected Access 2) for security (authentication and encryption) between access points and clients. According to the IEEE 802.11i-2004 standard, wireless networks secured with WPA2-PSK (Pre-Shared Key) are required to be protected with a passphrase between 8 to 63 ASCII characters. However, a poorly chosen passphrase significantly reduces the effectiveness of both WPA2 and WPA3-Personal Transition Mode. The objective of this paper is to empirically evaluate password choices in the wild and evaluate weakness in current common practices. We collected a total of 3,352 password hashes from Wi-Fi access points and determine the passphrases that were protecting them. We then analyze these passwords to investigate the impact of user’s behavior and preference for convenience on passphrase strength in secured private Wi-Fi networks in Singapore. We characterized the predictability of passphrases that use the minimum required length of 8 numeric or alphanumeric characters, and/or symbols stipulated in wireless security standards, and the usage of default passwords, and found that 16 percent of the passwords show such behavior. Our results also indicate the prevalence of the use of default passwords by hardware manufacturers. We correlate our results with our findings and recommend methods that will improve the overall security and future of our Wi-Fi networks. © 2025, CC BY.

关键词： Wireless local area networks (WLAN)

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A 2.2-3.6 GHz CMOS Reconfigurable Fourth-Order Bandpass Filter With Compact Size and High Selectivity Using Transformer-Type Resonators

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IEEE Transactions on Microwave Theory and Techniques 2023年第1期71卷 218-229页

作者： Li, Kun Liu, Bin Chi, Pei-Ling Wang, Yong Yang, Tao University of Electronic Science and Technology of China School of Electronic Science and Engineering Chengdu Sichuan610054 China National Chiao Tung University Department of Electrical and Computer Engineering Hsinchu300 Taiwan Nanhu Laboratory Research Center of Advanced Rf Chips and Systems Jiaxing Zhejiang314000 China

A compact reconfigurable CMOS bandpass filter (BPF) with high selectivity is proposed using transformer-type resonators in this article. The transformer-type resonator is constructed by a transformer loaded with parallel varactors for frequency tuning, and two varactors are then added across primary wind and secondary wind for coupling tuning. With the transformer-type structure, one resonator is formed inside another resonator, thus fully utilizing the chip area and resulting in a miniaturized structure. Magnetic and electrical couplings are formed within the transformer-type resonator and facilitate the bandwidth (BW) tuning. The quality factor (Q) of each resonator is improved by cross-coupled negative resistance structure. Meanwhile, two pairs of transformer-type resonators are placed side-by-side and naturally form a quadruplet structure;as a result, two transmission zeros (TZs) are introduced at each side of the passband thus significantly improving the selectivity and stopband rejection of the BPF. The proposed tunable on-chip BPF is manufactured by a commercial 55 nm bulk CMOS technology with a core area of 1.48 × 0.54 mm2. The filter center frequency (CF) can be tuned from 2.2 to 3.6 GHz, while the 3 dB fractional BW (FBW) can be tuned from 14% to 33%. The shape factor of the proposed filter is 1.4-1.9. © 1963-2012 IEEE.

关键词： Varactors

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A NOVEL MODEL FOR THE MATERIAL SELECTION OF SMART OBJECTS FOR HAND-REHABILITATION: A CASE STUDY 24

A NOVEL MODEL FOR THE MATERIAL SELECTION OF SMART OBJECTS FO...

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24th International Conference on engineering design, ICED 2023

作者： Bos, Mikaël Ivar Karahanoǧlu, Armaǧan Haarman, Juliet Nizamis, Kostas Chair of Systems Engineering and Multidisciplinary Design Department of Design Production and Management Faculty of Engineering Technology University of Twente Enschede Netherlands Interaction Design Research Group Department of Design Production and Management Faculty of Engineering Technology University of Twente Enschede Netherlands Human Media Interaction Group Faculty of Electrical Engineering Mathematics and Computer Science University of Twente Enschede Netherlands

Home hand rehabilitation for stroke is becoming increasingly important due to logistic and financial challenges. Developing Daily-life Integrated Hand-rehabilitation Products (DIHP) aims to enable the application of at-home rehabilitation. The materials of these products are essential for their success, however, selecting materials for DIHP has not been investigated yet. Previous research on material selection showed that it is done strictly on material properties or based on a human-centered approach. Hence, in this study, we propose a hybrid model for choosing materials for DIHP. To achieve this, we first combined the findings of previous material selection processes into a comprehensive material selection model. We applied this model in a case study, in which we first selected three materials based on their properties. Following, we 3d printed a DIHP out of the chosen materials and tested the feeling of the materials with multiple expert groups. Our findings suggest that the proposed material selection method is promising and highlights that our comprehensive model provides more insights when compared to a strict material property-based selection. © The Author(s), 2023. Published by Cambridge University Press.

关键词： 3D printing

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Adapting to Human Preferences to Lead or Follow in Human-Robot Collaboration: A System Evaluation

arXiv

引用

arXiv 2023年

作者： Noormohammadi-Asl, Ali Ayub, Ali Smith, Stephen L. Dautenhahn, Kerstin The Department of Systems Design Engineering The Department of Electrical and Computer Engineering The University of Waterloo WaterlooON Canada

With the introduction of collaborative robots, humans and robots can now work together in close proximity and share the same workspace. However, this collaboration presents various challenges that need to be addressed to ensure seamless cooperation between the agents. This paper focuses on task planning for human-robot collaboration, taking into account the human’s performance and their preference for following or leading. Unlike conventional task allocation methods, the proposed system allows both the robot and human to select and assign tasks to each other. Our previous studies evaluated the proposed framework in a computer simulation environment. This paper extends the research by implementing the algorithm in a real scenario where a human collaborates with a Fetch mobile manipulator robot. We briefly describe the experimental setup, procedure and implementation of the planned user study. As a first step, in this paper, we report on a system evaluation study where the experimenter enacted different possible behaviours in terms of leader/follower preferences that can occur in a user study. Results show that the robot can adapt and respond appropriately to different human agent behaviours, enacted by the experimenter. A future user study will evaluate the system with human participants. © 2023, CC BY-NC-ND.

关键词： Manipulators

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Adapting to Human Preferences to Lead or Follow in Human-Robot Collaboration: A System Evaluation

Adapting to Human Preferences to Lead or Follow in Human-Rob...

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IEEE International Workshop on Robot and Human Communication (ROMAN)

作者： Ali Noormohammadi-Asl Ali Ayub Stephen L. Smith Kerstin Dautenhahn Department of Systems Design Engineering and the Department of Electrical and Computer Engineering University of Waterloo Waterloo ON Canada

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Network-Based Rail Running Band Anomaly Recognition via Recurrent Attention Graphs

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IEEE Transactions on Automation Science and engineering 2025年 22卷 15381-15395页

作者： Ni, Xuefeng Fieguth, Paul W. Ma, Ziji Shi, Bo Liu, Hongli Hunan University College of Electrical and Information Engineering China University of Waterloo Department of Systems Design Engineering Canada The Hong Kong University of Science and Technology Department of Computer Science and Engineering Hong Kong

Anomaly detection for rail running bands, the pattern of wheel–rail contact area, is crucial to analyze composite rail irregularities. This paper presents an all-weather vision-based solution for running-band inspection. However, two major algorithmic challenges restrict inspection effectiveness: 1) the identification of high-quality features for diversified and imbalanced data subject to noise and outliers, and 2) inferring implicit anomaly co-occurrence patterns. We regard overall running-band anomaly detection as a multi-label classification problem and develop a novel deep multi-anomaly recognition network via recurrent attention graphs (RAGRN). The proposed RAGRN consists of two fundamental components, each directly addressing the two major challenges of this paper: 1) Class-specific features are extracted for fine-grained discrimination via split-channel and gradient-guided class-specific attention mechanisms;2) We develop a multi-anomaly classifier, which effectively captures long-distance correlation features via a recurrent attention graph with visual and statistical guidance for graph propagation, containing prior statistical and image-specific information. The experiments and statistical analyses demonstrate that RAGRN outperforms all related state-of-the-art frameworks and has the potential to be applied to practical inspection. © 2004-2012 IEEE.

关键词： Network theory (graphs)

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Awareness and Assistance: General Drivers' Cyber Threat Identification and the Role of an In-Vehicle Console Display

Awareness and Assistance: General Drivers' Cyber Threat Iden...

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International Conference on Intelligent Transportation

作者： Fan He Juliet Kern Sebastian Fischmeister Catherine M. Burns Department of Systems Design Engineering University of Waterloo Waterloo ON Canada Department of Electrical and Computer Engineering University of Waterloo Waterloo ON Canada

ISBN: (数字)9798331505929

ISBN: (纸本)9798331505936

This online survey-based study investigated human drivers' awareness of cyber threats to automated vehicles from a human-centric perspective. Findings show drivers more readily identify explicit threats, particularly affecting vehicle motion, but struggle to grasp their origins. The study also assesses the effectiveness of Tesla Model 3's console display, as an example of a popular modern vehicle dashboard interface, in aiding threat identification, with drivers viewing it as moderately helpful. However, the driver's performance in identifying threat details is limited. This work's results highlight the challenges drivers face in responding to cyber threats and their need for information displayed for cyber threat diagnostics, actionable guidance, and a potential dedicated operation center for timely, systematic cyber threat management in modern driving systems.

关键词： Systematics Focusing Vectors Intelligent transportation systems Faces Vehicles

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