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Mechanically reprogrammable Pancharatnam-Berry metasurface for microwaves

Advanced Photonics 2022年第1期4卷 69-79页

作者： Quan Xu Xiaoqiang Su Xueqian Zhang Lijuan Dong Lifeng Liu Yunlong Shi Qiu Wang Ming Kang Andrea Alù Shuang Zhang Jiaguang Han Weili Zhang Tianjin University Center for Terahertz Waves and College of Precision Instrument and Optoelectronics EngineeringKey Laboratory of Optoelectronic Information Technology(Ministry of Education of China)TianjinChina Shanxi Datong University Institute of Solid State Physics and College of Physics and Electronic ScienceShanxi Province Key Laboratory of Microstructure Electromagnetic Functional MaterialsDatongChina Wuhan University of Technology School of Information EngineeringWuhanChina Tianjin Normal University College of Physics and Materials ScienceTianjinChina City University of New York Advanced Science Research CenterPhotonics InitiativeNew YorkUnited States City University of New York Graduate CenterPhysics ProgramNew YorkUnited States University of Hong Kong Faculty of ScienceDepartment of PhysicsHong KongChina University of Hong Kong Department of Electrical and Electronic EngineeringHong KongChina Guilin University of Electronic Technology Guangxi Key Laboratory of Optoelectronic Information ProcessingSchool of Optoelectronic EngineeringGuilinChina Oklahoma State University School of Electrical and Computer EngineeringStillwaterOklahomaUnited States

Metasurfaces have enabled the realization of several optical functionalities over an ultrathin platform,fostering the exciting field of flat *** metasurfaces are achieved by arranging a layout of static meta-atoms to imprint a desired operation on the impinging wavefront,but their functionality cannot be *** and programmability of metasurfaces are the next important step to broaden their impact,adding customized on-demand functionality in which each meta-atom can be individually *** demonstrate a mechanical metasurface platform with controllable rotation at the meta-atom level,which can implement continuous Pancharatnam–Berry phase control of circularly polarized *** the proof-of-concept experiments,we demonstrate metalensing,focused vortex beam generation,and holographic imaging in the same metasurface template,exhibiting versatility and superior *** dynamic control of electromagnetic waves using a single,low-cost metasurface paves an avenue towards practical applications,driving the field of reprogrammable intelligent metasurfaces for a variety of applications.

关键词： reprogrammable metasurfaces Pancharatnam-Berry phase mechanical metasurfaces microwaves

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Large AI Models in Health Informatics: Applications, Challenges, and the Future

arXiv

引用

arXiv 2023年

作者： Qiu, Jianing Li, Lin Sun, Jiankai Peng, Jiachuan Shi, Peilun Zhang, Ruiyang Dong, Yinzhao Lam, Kyle Lo, Frank P.-W. Xiao, Bo Yuan, Wu Wang, Ningli Xu, Dong Lo, Benny The Department of Computing Imperial College London United Kingdom The Department of Biomedical Engineering The Chinese University of Hong Kong Hong Kong Ltd. Hong Kong The Department of Informatics King’s College London United Kingdom The School of Engineering Stanford University United States The Department of Engineering Science University of Oxford United Kingdom The Faculty of Engineering The University of Hong Kong Hong Kong The Department of Surgery and Cancer Imperial College London United Kingdom The Hamlyn Centre for Robotic Surgery Imperial College London United Kingdom Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University China Beijing Ophthalmology & Visual Sciences Key Laboratory Beijing China The Department of Electrical Engineering and Computer Science United States The Christopher S. Bond Life Sciences Center University of Missouri United States The Facualty of Medicine Imperial College London United Kingdom

Large AI models, or foundation models, are models recently emerging with massive scales both parameter-wise and data-wise, the magnitudes of which can reach beyond billions. Once pretrained, large AI models demonstrate impressive performance in various downstream tasks. A prime example is ChatGPT, whose capability has compelled people’s imagination about the far-reaching influence that large AI models can have and their potential to transform different domains of our lives. In health informatics, the advent of large AI models has brought new paradigms for the design of methodologies. The scale of multi-modal data in the biomedical and health domain has been ever-expanding especially since the community embraced the era of deep learning, which provides the ground to develop, validate, and advance large AI models for breakthroughs in health-related areas. This article presents a comprehensive review of large AI models, from background to their applications. We identify seven key sectors in which large AI models are applicable and might have substantial influence, including 1) bioinformatics;2) medical diagnosis;3) medical imaging;4) medical © 2023, CC BY-NC-ND.

关键词： Medical imaging

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Homonuclear J-coupling spectroscopy at low magnetic fields using spin-lock induced crossing

arXiv

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arXiv 2021年

作者： DeVience, Stephen J. Greer, Mason Mandal, Soumyajit Rosen, Matthew S. Scalar Magnetics LLC Windsor MillMD21244 United States Department of Electrical Computer and Systems Engineering Case Western Reserve University ClevelandOH44106 United States Department of Electrical and Computer Engineering University of Florida GainesvilleFL32611 United States Athinoula A Martinos Center for Biomedical Engineering Massachusetts General Hospital CharlestownMA02129 United States

Nuclear magnetic resonance (NMR) spectroscopy usually requires high magnetic fields to create spectral resolution among different proton species. At low fields, chemical shift dispersion is insufficient to separate the species, and the spectrum exhibits just a single line. In this work, we demonstrate that spectra can nevertheless be acquired at low field using a novel pulse sequence called spin-lock induced crossing (SLIC). This probes energy level crossings induced by a weak spin-locking pulse and produces a unique J-coupling spectrum for most organic molecules. Unlike other forms of low-field J-coupling spectroscopy, our technique does not require the presence of heteronuclei and can be used for most compounds in their native state. We performed SLIC spectroscopy on a number of small molecules at 276 kHz and 20.8 MHZ, and we show that SLIC spectra can be simulated in good agreement with measurements. © 2021, CC BY.

关键词： Nuclear magnetic resonance spectroscopy

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Hypoglycemia Prevention via Personalized Glucose-Insulin Models Identified in Free-Living Conditions

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Journal of Diabetes Science and Technology 2019年第6期13卷 1008-1016页

作者： Toffanin, Chiara Aiello, Eleonora Maria Cobelli, Claudio Magni, Lalo Department of Electrical Computer and Biomedical Engineering University of Pavia Italy Department of Information Engineering University of Padova Italy Department of Civil Engineering and Architecture University of Pavia Italy

Background: The objective of this research is to show the effectiveness of individualized hypoglycemia predictive alerts (IHPAs) based on patient-tailored glucose-insulin models (PTMs) for different subjects. Interpatient variability calls for PTMs that have been identified from data collected in free-living conditions during a one-month trial. Methods: A new impulse-response (IR) identification technique has been applied to free-living data in order to identify PTMs that are able to predict the future glucose trends and prevent hypoglycemia events. Impulse response has been applied to seven patients with type 1 diabetes (T1D) of the University of Amsterdam Medical Centre. Individualized hypoglycemia predictive alert has been designed for each patient thanks to the good prediction capabilities of PTMs. Results: The PTMs performance is evaluated in terms of index of fitting (FIT), coefficient of determination, and Pearson’s correlation coefficient with a population FIT of 63.74%. The IHPAs are evaluated on seven patients with T1D with the aim of predicting in advance (between 45 and 10 minutes) the unavoidable hypoglycemia events;these systems show better performance in terms of sensitivity, precision, and accuracy with respect to previously published results. Conclusion: The proposed work shows the successful results obtained applying the IR to an entire set of patients, participants of a one-month trial. Individualized hypoglycemia predictive alerts are evaluated in terms of hypoglycemia prevention: the use of a PTM allows to detect 84.67% of the hypoglycemia events occurred during a one-month trial on average with less than 0.4% of false alarms. The promising prediction capabilities of PTMs can be a key ingredient for new generations of individualized model predictive control for artificial pancreas. © 2019 Diabetes Technology Society.

关键词： artificial pancreas hypoglycemia prevention model identification safety system

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Unavoidable emergent biaxiality in chiral molecular-colloidal hybrid liquid crystals

arXiv

引用

arXiv 2023年

作者： Wu, Jin-Sheng Lázaro, Marina Torres Ghosh, Souvik Mundoor, Haridas Wensink, Henricus H. Smalyukh, Ivan I. Department of Physics and Chemical Physics Program University of Colorado BoulderCO United States Laboratoire de Physique des Solides UMR 8502 Université Paris-Saclay CNRS Orsay91405 France International Institute for Sustainability with Knotted Chiral Meta Matter Hiroshima University Higashihiroshima Japan Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program and Soft Materials Research Center University of Colorado BoulderCO United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States

Chiral nematic or cholesteric liquid crystals (LCs) are chiral mesophases with long-ranged orientational order featuring a quasi-layered periodicity imparted by a helical director configuration but lacking positional order. Doping molecular cholesteric LCs with thin colloidal rods with a large length-to-width ratio or disks with a large diameter-to-thickness ratio adds another level of complexity to the system because of the interplay between weak surface anchoring boundary conditions and bulk-based elastic distortions around the particle-LC interface. By using colloidal disks and rods with different geometric shapes and boundary conditions, we demonstrate that these anisotropic colloidal inclusions exhibit biaxial orientational probability distributions, where they have tendencies to orient with the long rod axes and disk normals perpendicular to the helix axis, thus imparting strong local biaxiality on the hybrid cholesteric LC structure. Unlike the situation in non-chiral hybrid molecular-colloidal LCs, where biaxial order emerges only at modest to high volume fractions of the anisotropic colloidal particles, above a uniaxial-biaxial transition concentration, the orientational probability distribution of colloidal inclusions immersed in chiral nematic hosts are unavoidably biaxial even at vanishingly low particle volume fractions. In addition, the colloidal inclusions induce local biaxiality in the molecular orientational order of the LC host medium, which enhances the weak biaxiality of the LC in a chiral nematic phase coming from the symmetry breaking caused by the presence of the helical axis. With the help of analytical modeling and computer simulations based on minimizing the Landau de Gennes free energy of the host LC around the colloidal inclusions, we explain our experimental findings and conclude that the biaxial order of chiral molecular-colloidal LCs is strongly enhanced as compared to both achiral molecular-colloidal LCs and molecular cholesteric LCs

关键词： Probability distributions

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An aerodynamic analysis of energy saving car based on computational fluid dynamic using solidworks

引用

AIP Conference Proceedings 2024年第1期3222卷

作者： R. F. Naryanto A. Setiyawan A. Roziqin S. Maulana F. B. Darsono I. G. M. Andika M. K. Delimayanti R. A. Widodo Mechanical Engineering Department Universitas Negeri Semarang Semarang Indonesia Automotive Engineering Education Universitas Negeri Semarang Semarang Indonesia Computer and Informatics Engineering Department Politeknik Negeri Jakarta Depok Indonesia Master Program in Applied Electrical Engineering Politeknik Negeri Jakarta Depok Indonesia

Improved transportation increased the amount of fuel consumption required. Transportation in Indonesia is the largest oil-consuming sector, with a percentage of 40.1% of the total. Vehicle manufacturers are required to produce a vehicle that has a high level of fuel efficiency. This study aims to determine the aerodynamics of energy-efficient vehicle bodies based on computational fluid dynamics (CFD). This research was conducted using SolidWorks to implement the model. This study examined the variations in airflow velocity at 25, 40, 55, and 70 km/hour. It can be found that the coefficient of drag (Cd) values of the latest body designs with variations in airflow velocity were increased value. The calculation results of the coefficient of drag values were 0.149, 0.154, 0.162, and 0.162, respectively, and the average value was 0.156. In this research, we have found that the energy-saving car body can reduce the drag coefficient compared with the previous study.

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WSTac: Interactive Surface Perception based on Whisker-Inspired and Self-Illuminated Vision-Based Tactile Sensor

arXiv

引用

arXiv 2023年

作者： Lei, Kai Chong Sou, Kit Wa Chan, Wang Sing Yan, Jiayi Ping, Siqi Peng, Dengfeng Ding, Wenbo Zhang, Xiao-Ping Tsinghua-Berkeley Shenzhen Institute Shenzhen International Graduate School Tsinghua University China Shenzhen International Graduate School Tsinghua University China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen University China Tsinghua-Berkeley Shenzhen Institute Shenzhen International Graduate School Tsinghua University RISC-V International Open Source Laboratory China Department of Electrical Computer and Biomedical Engineering Ryerson University Canada

Modern Visual-Based Tactile Sensors (VBTSs) use cost-effective cameras to track elastomer deformation, but struggle with ambient light interference. Solutions typically involve using internal LEDs and blocking external light, thus adding complexity. Creating a VBTS resistant to ambient light with just a camera and an elastomer remains a challenge. In this work, we introduce WStac, a self-illuminating VBTS comprising a mechanoluminescence (ML) whisker elastomer, camera, and 3D printed parts. The ML whisker elastomer, inspired by the touch sensitivity of vibrissae, offers both light isolation and high ML intensity under stress, thereby removing the necessity for additional LED modules. With the incorporation of machine learning, the sensor effectively utilizes the dynamic contact variations of 25 whiskers to successfully perform tasks like speed regression, directional identification, and texture classification. Videos are available at: https://***/view/wstac/. Copyright © 2023, The Authors. All rights reserved.

关键词： Cost effectiveness

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Dynamic Spectrum Access for Femtocell Networks: A Graph Neural Network Based Learning Approach

Dynamic Spectrum Access for Femtocell Networks: A Graph Neur...

引用

International Conference on Computing, Networking and Communications (ICNC)

作者： He Jiang Haibo He Lingjia Liu Department of Electrical Computer and Biomedical Engineering University of Rhode Island Kingston USA Bradley Department of Electrical Computer Engineering Virginia Tech Blacksburg VA USA

ISBN: (数字)9781728149059

ISBN: (纸本)9781728149066

This paper concerns the dynamic spectrum access problem for femtocell networks, where traffic loads are different among cells. We model the interference relationship of the femtocell networks with conflict graphs, and a graphical game is employed as the channel access coordination mechanism. A graph neural network based architecture is proposed, which directly maps traffic loads to the channel access scheme for each femtocell. With our method, each femtocell first estimates the qualities of all available channels based on the information from its neighbors, and then the channels of the highest quality are accessed. A multiagent reinforcement learning framework is designed to train the proposed architecture to make accurate estimations of channel quality.

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Electromagnetic Modeling of Lossy Materials with a Potential-Based Boundary Element Method

arXiv

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arXiv 2021年

作者： Sharma, Shashwat Triverio, Piero Edward S. Rogers Sr. Department of Electrical & Computer Engineering University of Toronto TorontoONM5S 3G4 Canada Edward S. Rogers Sr. Department of Electrical & Computer Engineering Institute of Biomedical Engineering University of Toronto TorontoONM5S 3G4 Canada

The boundary element method (BEM) enables solving three-dimensional electromagnetic problems using a two-dimensional surface mesh, making it appealing for applications ranging from electrical interconnect analysis to the design of metasurfaces. The BEM typically involves the electric and magnetic fields as unknown quantities. Formulations based on electromagnetic potentials rather than fields have garnered interest recently, for two main reasons: (a) they are inherently stable at low frequencies, unlike many field-based approaches, and (b) potentials provide a more direct interface to quantum physical phenomena. Existing potential-based formulations for electromagnetic scattering have been proposed primarily for perfect conductors. We develop a potential-based BEM formulation which can capture both dielectric and conductive losses, and accurately models the skin effect over broad ranges of frequency. The accuracy of the proposed formulation is validated through canonical and realistic numerical examples. Copyright © 2021, The Authors. All rights reserved.

关键词： Boundary element method

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MobiExpressNet: A Deep Learning Network for Face Expression Recognition on Smart Phones

MobiExpressNet: A Deep Learning Network for Face Expression ...

引用

IEEE International Conference on Consumer Electronics (ICCE)

作者： Shane F. Cotter Electrical Computer & Biomedical Engineering Department Union College Schenectady NY USA

ISBN: (数字)9781728151861

ISBN: (纸本)9781728151878

Accurate Face Expression Recognition (FER) on a smart phone is useful in many applications which respond to a user's emotional state. However, the more limited computational power available on these devices restricts the complexity of developed algorithms. We introduce a new lightweight Deep Learning model, MobiExpressNet, for FER. The model relies on depthwise separable convolutions to limit the complexity, and we adopt a fast downsampling approach together with few layers in the architecture to keep the model size very small. Through exploring possible variations in the model structure, we determined that the best network model gave an accuracy of 67.96% on the challenging FER2013 dataset which exceeds human accuracy by 2.5%. The MobiExpressNet model size and FLOPs are shown to be over 5 times smaller than the smallest MobileNet model which makes the developed model very attractive for real-time applications.

关键词： Computational modeling computer architecture Face Deep learning Feature extraction Face recognition Emotion recognition

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