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Low mechanical loss and high refractive index in amorphous Ta2O5 films grown by magnetron sputtering

Physical Review Materials 2024年第3期8卷 035603-035603页

作者： M. Molina-Ruiz K. Shukla A. Ananyeva G. Vajente M. R. Abernathy T. H. Metcalf X. Liu A. Markosyan R. Bassiri M. M. Fejer M. Fazio L. Yang C. S. Menoni F. Hellman Department of Physics University of California Berkeley Berkeley California 94720 USA Department of Materials Science and Engineering University of California Berkeley Berkeley California 94720 USA LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Naval Research Laboratory Washington DC 20375 USA Edward L. Ginzton Laboratory Stanford University Stanford California 94305 USA Department of Applied Physics Stanford University Stanford California 94305 USA Department of Electrical and Computer Engineering Colorado State University Fort Collins Colorado 80523 USA Department of Chemistry Colorado State University Fort Collins Colorado 80523 USA

The ability to observe astronomical events through the detection of gravitational waves relies on the quality of multilayer coatings used on the optical mirrors of interferometers. Amorphous Ta2O5 (including TiO2:Ta2O5) currently limits detector sensitivity due to high mechanical loss. In this paper, mechanical loss measured at both cryogenic and room temperatures of amorphous Ta2O5 films grown by magnetron sputtering and annealed in air at 500 ∘C is shown to decrease for elevated growth temperature. Films grown at 310 ∘C and annealed yield a mechanical loss of 3.1×10−4 at room temperature, the lowest value reported for pure amorphous Ta2O5 grown by magnetron sputtering to date, and comparable to the lowest values obtained for films grown by ion beam sputtering. Additionally, the refractive index n increases 6% for elevated growth temperature, which could lead to improved sensitivity of gravitational-wave detectors by allowing a thickness reduction in the mirrors' coatings. Structural characterization suggests that the observed mechanical loss reduction in amorphous Ta2O5 films with increasing growth temperature correlates with a reduction in the coordination number between oxygen and tantalum atoms, consistent with TaOx polyhedra with increased corner-sharing and reduced edge- and face-sharing structures.

关键词： Structural properties Amorphous materials Film deposition Gravitational wave detectors Physical vapor deposition

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Leveraging Randomization-Inspired Hybrid Deep Learning for Enhanced Diabetic Retinopathy Detection Via Multi-Scale Image Analysis

SSRN

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SSRN 2024年

作者： Mutawa, A.M. Hemalakshmi, G.R. Prakash, N.B. Murugappan, M. Computer Engineering Department College of Engineering and Petroleum Kuwait University Safat13060 Kuwait School of Computing Science and Engineering VIT Bhopal University Madhya Pradesh India Department of Electrical and Electronics Engineering National Engineering College Tamilnadu Kovilpatti India Research Lab Department of Electronics and Communication Engineering Kuwait College of Science and Technology Block 4 Doha13133 Kuwait Department of Electronics and Communication Engineering Faculty of Engineering Vels Institute of Sciences Technology and Advanced Studies Tamilnadu Chennai600117 India Universiti Malaysia Perlis Perlis Kangar02600 Malaysia

Diabetic retinopathy (DR), a critical complication of diabetes, significantly increases the risk of vision loss. Prompt detection is essential for effective intervention, yet existing diagnostic practices are resource-intensive, inconsistent, and often inaccessible. This study pioneers an innovative framework, leveraging a hybrid Convolutional Neural Network-Radial Basis Function (CNN-RBF) classifier, synergized with Multi-Scale Discriminative Robust Local Binary Pattern (MS-DRLBP) features, to fortify the detection of DR. Inspired by principles of randomization-based learning, our approach incorporates elements of stochastic modeling within the CNN-RBF architecture to optimize feature extraction and classification, mirroring the efficiency of non-iterative training processes. Through sophisticated image preprocessing, including advanced noise reduction and morphological techniques, complemented by Otsu’s thresholding for precise blood vessel segmentation, we enhance the model's diagnostic capability. Our methodology exhibits superior performance in DR screening, achieving benchmarks of 96.10% precision, 95.35% sensitivity, 97.06% specificity, and 96.10% accuracy, markedly surpassing conventional diagnostic methods. Applied across various publicly available datasets, this research not only advances the precision of DR diagnostics but also contributes to the broader discourse on the potential of hybrid, randomization-inspired neural networks in medical imaging. This fusion of deep learning innovation with the principles of randomization-based algorithms opens new avenues for developing accessible, accurate diagnostic tools, potentially alleviating the global impact of diabetic vision loss.. © 2024, The Authors. All rights reserved.

关键词： Stochastic systems

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Bilingual Road Text Recognition Based on a Hybrid Model of CTC and Attention

Bilingual Road Text Recognition Based on a Hybrid Model of C...

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ACS/IEEE International Conference on computer Systems and Applications

作者： Ridha Zaghdoud Khalil Boukthir Tarek M. Hamdani Adel M. Alimi University of Sousse ISITCom Hammam Sousse Sousse Tunisia REsearch Groups in Intelligent Machines (REGIM-Laboratory National Engineering School of Sfax) (ENIS) University of Sfax Sfax Tunisia Higher Institute of Computer Science Mahdia(ISIMa) University of Monastir Monatsir Tunisia Department of Electrical and Electronic Engineering Science University of Johannesburg Faculty of Engineering and the Built Environment Johannesburg South Africa

ISBN: (数字)9798331518240

ISBN: (纸本)9798331518257

The recognition of Arabic and Latin text for autonomous cars involves developing systems and algorithms capable of accurately detecting and understanding Arabic characters and words from images. This technology is crucial in enabling autonomous vehicles to interpret and respond to Arabic and Latin traffic signs, road markings, and other textual information on the roads. The development of a reliable identification system, particularly for Arabic is challenging if a dataset contains differences in text size, typefaces, colors, orientation, illumination and noise. These problems become more difficult to solve. By exploiting the benefits of both CTC (Connectionist Temporal Classification) and Attention mechanisms to improve the accuracy and robustness of the recognition system, a hybrid CTC and Attention model is used in the prediction stage for Arabic-Latin image text recognition. Current research is focusing intensively on text panels in Latin, while other scripts, such as Arabic, remain little valued. For this reason, the NaSTSArLaTR (Natural Scene Traffic Sign and Panel Guide Arabic-Latin Text Recognition) dataset has been set up to validate our experiments. Our tests found that the suggested hybrid CTC and Attention model outperformed either Attention or CTC alone in the prediction phase. The dataset is publicly available in IEEE DataPort https://***/10.21227/phyg-_jc98.

关键词： Training Image recognition Text analysis Text recognition Roads Lighting Predictive models Robustness Decoding Multilingual

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UAV Swarm-enabled Collaborative Secure Relay Communications with Time-domain Colluding Eavesdropper

arXiv

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arXiv 2023年

作者： Zhang, Chuang Sun, Geng Wu, Qingqing Li, Jiahui Liang, Shuang Niyato, Dusit Leung, Victor C.M. The College of Computer Science and Technology Jilin University Changchun130012 China The Key Laboratory of Symbolic Computation and Knowledge Engineering Ministry of Education Jilin University Changchun130012 China The Department of Electronic Engineering Shanghai Jiao Tong University Shanghai China Pillar of Engineering Systems and Design Singapore University of Technology and Design 487372 Singapore The School of Information Science and Technology Northeast Normal University Changchun130024 China The School of Computer Science and Engineering Nanyang Technological University 639798 Singapore The College of Computer Science and Software Engineering Shenzhen University Shenzhen518060 China The Department of Electrical and Computer Engineering University of British Columbia VancouverBCV6T 1Z4 Canada

Unmanned aerial vehicles (UAVs) as aerial relays are practically appealing for assisting Internet of Things (IoT) network. In this work, we aim to utilize the UAV swarm to assist the secure communication between the micro base station (MBS) equipped with the planar array antenna (PAA) and the IoT terminal devices by collaborative beamforming (CB), so as to counteract the effects of collusive eavesdropping attacks in time-domain. Specifically, we formulate a UAV swarm-enabled secure relay multi-objective optimization problem (US2RMOP) for simultaneously maximizing the achievable sum rate of associated IoT terminal devices, minimizing the achievable sum rate of the eavesdropper and minimizing the energy consumption of UAV swarm, by jointly optimizing the excitation current weights of both MBS and UAV swarm, the selection of the UAV receiver, the position of UAVs and user association order of IoT terminal devices. Furthermore, the formulated US2RMOP is proved to be a non-convex, NP-hard and large-scale optimization problem. Therefore, we propose an improved multi-objective grasshopper algorithm (IMOGOA) with some specific designs to address the problem. Simulation results exhibit the effectiveness of the proposed UAV swarm-enabled collaborative secure relay strategy and demonstrate the superiority of IMOGOA. Copyright © 2023, The Authors. All rights reserved.

关键词： Multiobjective optimization

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Molecular Communication for Quorum Sensing Inspired Cooperative Drug Delivery

arXiv

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arXiv 2023年

作者： Fang, Yuting Johnston, Stuart T. Faria, Matt Huang, Xinyu Eckford, Andrew W. Evans, Jamie Department of Electrical and Electronic Engineering School of Mathematics and Statistics and Systems Biology Laboratory Department of Biomedical Engineering Department of Biomedical Engineering ARC Centre of Excellence in Covergent Bio-Nano Science and Technology The University of Melbourne ParkvilleVIC3010 Australia School of Engineering Australian National University CanberraACT2600 Australia Department of Electrical Engineering and Computer Science York University TorontoONM3J 1P3 Canada

A cooperative drug delivery system is proposed, where quorum sensing (QS), a density-dependent bacterial behavior coordination mechanism, is employed by synthetic bacterium-based nanomachines (B-NMs) for controllable drug delivery. In our proposed system, drug delivery is only triggered when there are enough QS molecules, which in turn only happens when there are enough B-NMs. This makes the proposed system can be used to achieve a high release rate of drug molecules from a high number of B-NMs when the population density of B-NMs may not be known. Analytical expressions for i) the expected activation probability of the B-NM due to randomly-distributed B-NMs and ii) the expected aggregate absorption rate of drug molecules due to randomly-distributed QS activated B-NMs are derived. Analytical results are verified by particle-based simulations. The derived results can help to predict and control the impact of environmental factors (e.g. diffusion coefficient and degradation rate) on the absorption rate of drug molecules since rigorous diffusion-based molecular channels are considered. Our results show that the activation probability at the B-NM increases as this B-NM is located closer to the center of the B-NM population and the aggregate absorption rate of the drug molecules non-linearly increases as the population density increases. © 2023, CC BY.

关键词： Aggregates

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Dynamic State Estimation-Based Protection for Induction Motor Loads

Dynamic State Estimation-Based Protection for Induction Moto...

引用

Annual North-American Power Symposium

作者： Arthur K. Barnes Sarbajit Basu Adam Mate Advanced Network Science Initiative at Los Alamos National Laboratory Los Alamos NM USA Klipsch School of Electrical and Computer Engineering New Mexico State University Las Cruces NM USA

ISBN: (纸本)9781665499224

Ensuring protective device coordination is critical to maintain the resilience and improve the reliability of large microgrids. Inverter-interfaced generation, however, poses significant challenges when designing protection systems. Traditional time-overcurrent protective devices are unsuitable on account of the lack of fault current. Present industry practice is to force all inverters to shut down during faults, which prevents large microgrids from operating in a resilient and reliable manner. Dynamic state estimation (DSE) has been proposed for line protection, and more recently for the protection of load buses or downstream radial portions of microgrids. However, only passive loads with series resistive-inductive loads have been tested with DSE, even though the behavior of dynamic loads – such as induction motors or power electronics – may differ significantly during faults. This paper considers the case of applying DSE to protecting a load bus serving a three-phase induction motor.

关键词： Induction motors Power system dynamics Rectifiers Microgrids Transformers Behavioral sciences Reliability

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Joint Task Offloading and Resource Allocation in Aerial-Terrestrial UAV Networks with Edge and Fog Computing for Post-Disaster Rescue

arXiv

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arXiv 2023年

作者： Sun, Geng He, Long Sun, Zemin Wu, Qingqing Liang, Shuang Li, Jiahui Niyato, Dusit Leung, Victor C.M. The College of Computer Science and Technology Jilin University Changchun130012 China The Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun130012 China The Department of Electronic Engineering Shanghai Jiao Tong University Shanghai China The School of Information Science and Technology Northeast Normal University Changchun130024 China Pillar of Engineering Systems and Design Singapore University of Technology and Design 487372 Singapore The School of Computer Science and Engineering Nanyang Technological University Singapore639798 Singapore The College of Computer Science and Software Engineering Shenzhen University Shenzhen518060 China The Department of Electrical and Computer Engineering University of British Columbia VancouverBCV6T 1Z4 Canada

Unmanned aerial vehicles (UAVs) play an increasingly important role in assisting fast-response post-disaster rescue due to their fast deployment, flexible mobility, and low cost. However, UAVs face the challenges of limited battery capacity and computing resources, which could shorten the expected flight endurance of UAVs and increase the rescue response delay during performing mission-critical tasks. To address this challenge, we first present a three-layer post-disaster rescue computing architecture by leveraging the aerial-terrestrial edge capabilities of mobile edge computing (MEC) and vehicle fog computing (VFC), which consists of a vehicle fog layer, a UAV client layer, and a UAV edge layer. Moreover, we formulate a joint task offloading and resource allocation optimization problem (JTRAOP) with the aim of maximizing the time-average system utility. Since the formulated JTRAOP is proved to be NP-hard, we propose an MEC-VFC-aided task offloading and resource allocation (MVTORA) approach, which consists of a game theoretic algorithm for task offloading decision, a convex optimization-based algorithm for MEC resource allocation, and an evolutionary computation-based hybrid algorithm for VFC resource allocation. Simulation results validate that the proposed approach can achieve superior system performance compared to the other benchmark schemes, especially under heavy system workloads. Copyright © 2023, The Authors. All rights reserved.

关键词： Fog computing

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On Performance of Fluid Antenna System using Maximum Ratio Combining

arXiv

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arXiv 2023年

作者： Lai, Xiazhi Wu, Tuo Yao, Junteng Pan, Cunhua Elkashlan, Maged Wong, Kai-Kit The School of Computer Science Guangdong University of Education Guangdong Guangzhou China The School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom The Faculty of Electrical Engineering and Computer Science Ningbo University Ningbo315211 China The National Mobile Communications Research Laboratory Southeast University Nanjing210096 China The Department of Electronic and Electrical Engineering University College London LondonWC1E 6BT United Kingdom The Yonsei Frontier Laboratory The School of Integrated Technology Yonsei University Seoul03722 Korea Republic of

This letter investigates a fluid antenna system (FAS) where multiple ports can be activated for signal combining for enhanced receiver performance. Given M ports at the FAS, the best K ports out of the M available ports are selected before maximum ratio combining (MRC) is used to combine the received signals from the selected ports. The aim of this letter is to study the achievable performance of FAS when more than one ports can be activated. We do so by analyzing the outage probability of this setup in Rayleigh fading channels through the utilization of Gauss-Chebyshev integration, lower bound estimation, and high signal-to-noise ratio (SNR) asymptotic approximations. Our analytical results demonstrate that FAS can harness rich spatial diversity, which is confirmed by computer simulations. © 2023, CC BY.

关键词： Rayleigh fading

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Design and Grasping Experiments of Soft Humanoid Hand with Variable Stiffness 5th

Design and Grasping Experiments of Soft Humanoid Hand with V...

引用

5th International Conference on Cognitive Systems and Signal Processing, ICCSIP 2020

作者： Du, Shulin Wang, Qingchao Zhao, Yan Sun, Fuchun Lu, Xiao Fang, Bin Hou, Shoucheng College of Electrical Engineering and Automation Shandong University of Science and Technology Qingdao Shandong China Department of Computer Science and Technology Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing China Shanghai Institute of Satellite Engineering Shanghai China China University of Geosciences Beijing China

ISBN: (纸本)9789811623356

To improve the safety and adaptability of the human–machine and environment–machine interactions, the research of soft grippers has attracted much attention. In this study a novel Soft Humanoid Hand with Variable Stiffness (SHH-VS) is presented. The SHH-VS has 6 degrees of freedom, and the design of the soft finger with variable stiffness adopts the principle of layer jamming. The SHH-VS can complete grasping, pinching, holding, lifting and other multi-skill grasping operations, using the tendon-driven mechanism. Tactile sensors are installed at the fingertips, which can realize real-time feedback of tactile information. The SHH-VS has better flexibility, greater grasping power, and multi-skill grasping ability. Through a number of grasping experiments, it has been verified that the SHH-VS has greater reliability and safety, and can be used in various daily situations. © 2021, Springer Nature Singapore Pte Ltd.

关键词： Stiffness

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Characterizing Low-Frequency Qubit Noise

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Physical Review Applied 2023年第6期19卷 064066-064066页

作者： Filip Wudarski Yaxing Zhang Alexander N. Korotkov A.G. Petukhov M.I. Dykman Quantum Artificial Intelligence Laboratory Exploration Technology Directorate NASA Ames Research Center Moffett Field California 94035 USA USRA Research Institute for Advanced Computer Science (RIACS) Mountain View California 94043 USA Google Research Mountain View California 94043 USA Department of Electrical Engineering University of California Riverside California 92521 Department of Physics and Astronomy Michigan State University East Lansing Michigan 48824 USA

Fluctuations of the qubit frequencies are one of the major problems to overcome on the way to scalable quantum computers. Of particular importance are fluctuations with a correlation time that exceeds the decoherence time due to decay and dephasing by fast processes. The statistics of the fluctuations can be characterized by measuring the correlators of the outcomes of periodically repeated Ramsey measurements. We describe qubit dynamics during repeated measurements and evaluate the two-time correlator for noise from two-level systems and two- and three-time correlators for Gaussian noise. The explicit expressions for the correlators are compared with simulations. We find that, even though the three-time correlators for noise from two-level systems and for Gaussian noise are generally significantly different, already ten two-level systems can mimic Gaussian noise provided they are symmetric. This is not the case for asymmetric systems.

关键词： Quantum computation Quantum fluctuations & noise Quantum information with solid state qubits Quantum stochastic processes Superconducting qubits Monte Carlo methods Quantum master equation Two-level models

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