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arXiv 2024年

作者： Tostado-Marcos, Pablo Arneodo, Ezequiel M. Ostrowski, Lauren Brown, Daril E. Perez, Xavier A. Kadwory, Adam Stanwicks, Lauren L. Alothman, Abdullah Gentner, Timothy Q. Gilja, Vikash Department of Bioengineering University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States Department of Electrical and Computer Engineering University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States Department of Psychology University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States Department of Neurobiology University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States Neurosciences Graduate Program University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States

Complex, learned motor behaviors involve the coordination of large-scale neural activity across multiple brain regions, but our understanding of the population-level dynamics within different regions tied to the same behavior remains limited. Here, we investigate the neural population dynamics underlying learned vocal production in awake-singing songbirds. We use Neuropixels probes to record the simultaneous extracellular activity of populations of neurons in two regions of the vocal motor pathway. In line with observations made in non-human primates during limb-based motor tasks, we show that the population-level activity in both the premotor nucleus HVC and the motor nucleus RA is organized on low-dimensional neural manifolds upon which coordinated neural activity is well described by temporally structured trajectories during singing behavior. Both the HVC and RA latent trajectories provide relevant information to predict vocal sequence transitions between song syllables. However, the dynamics of these latent trajectories differ between regions. Our state-space models suggest a unique and continuous-over-time correspondence between the latent space of RA and vocal output, whereas the corresponding relationship for HVC exhibits a higher degree of neural variability. We then demonstrate that comparable high-fidelity reconstruction of continuous vocal outputs can be achieved from HVC and RA neural latents and spiking activity. Unlike those that use spiking activity, however, decoding models using neural latents generalize to novel sub-populations in each region, consistent with the existence of preserved manifolds that confine vocal-motor activity in HVC and RA. © 2024, CC BY.

关键词： Dynamics

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A Neural Ordinary Differential Equation Model for Visualizing Deep Neural Network Behaviors in Multi-Parametric MRI based Glioma Segmentation

arXiv

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arXiv 2022年

作者： Yang, Zhenyu Hu, Zongsheng Ji, Hangjie Lafata, Kyle Floyd, Scott Yin, Fang-Fang Wang, Chunhao Deparment of Radiation Oncology Duke University DurhamNC27710 United States Medical Physics Graduate Program Duke Kunshan University Jiangsu Kunshan215316 China Department of Mathematics North Carolina State University RaleighNC27695 United States Department of Radiology Duke University DurhamNC27710 United States Department of Electrical and Computer Engineering Duke University DurhamNC27710 United States

Purpose: To develop a neural ordinary differential equation (ODE) model for visualizing deep neural network behavior during multi-parametric MRI (mp-MRI) based glioma segmentation as a method to enhance deep learning explainability. Methods: By hypothesizing that deep feature extraction can be modeled as a spatiotemporally continuous process, we designed a novel deep learning model, neural ODE, in which deep feature extraction was governed by an ODE without explicit expression. The dynamics of 1) MR images after interactions with the deep neural network and 2) segmentation formation can thus be visualized after solving ODE. An accumulative contribution curve (ACC) was designed to quantitatively evaluate each MR image's utilization by the deep neural network towards the final segmentation results. The proposed neural ODE model was demonstrated using 369 glioma patients with a 4-modality mp-MRI protocol: T1, contrast-enhanced T1 (T1-Ce), T2, and FLAIR. Three neural ODE models were trained to segment enhancing tumor (ET), tumor core (TC), and whole tumor (WT), respectively. The key MR modalities with significant utilization by deep neural network were identified based on ACC analysis. Segmentation results by deep neural networks using only the key MR modalities were compared to the ones using all 4 MR modalities in terms of Dice coefficient, accuracy, sensitivity, and specificity. Results: All neural ODE models successfully illustrated image dynamics as expected. ACC analysis identified T1-Ce as the only key modality in ET and TC segmentations, while both FLAIR and T2 were key modalities in WT segmentation. Compared to the U-Net results using all 4 MR modalities, Dice coefficient of ET (0.784→0.775), TC (0.760→0.758), and WT (0.841→0.837) using the key modalities only had minimal differences without significance. Accuracy, sensitivity, and specificity results demonstrated the same patterns. Conclusion: The neural ODE model offers a new tool for optimizing the deep lear

关键词： Tumors

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Thermalization of fluorescent protein exciton-polaritons at room temperature

arXiv

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arXiv 2022年

作者： Satapathy, Sitakanta Liu, Bin Deshmukh, Prathmesh Molinaro, Paul M. Dirnberger, Florian Khatoniar, Mandeep Koder, Ronald L. Menon, Vinod M. Department of Physics Center for Discovery and Innovation The City College of New York 85 St. Nicholas Terrace New YorkNY10031 United States The PhD Program in Physics The Graduate Center of the City University of New York 365 5th Ave New YorkNY10016 United States Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States

Fluorescent proteins (FPs) have recently emerged as a serious contender for realizing ultra-low threshold room temperature exciton-polariton condensation and lasing. Our contribution investigates the thermalization of FP microcavity exciton-polaritons upon optical pumping under ambient conditions. We realize polariton cooling using a new FP molecule, called mScarlet, coupled strongly to the optical modes in a Fabry-Pérot cavity. Interestingly, at the threshold excitation energy (fluence) of ~9 nJ/pulse (15.6 mJ/cm2), we observe an effective temperature, Teff ~350 ± 35 K close to the lattice temperature indicative of strongly thermalized exciton-polaritons at equilibrium. This efficient thermalization results from the interplay of radiative pumping facilitated by the energetics of the lower polariton branch and the cavity Qfactor. Direct evidence for dramatic switching from an equilibrium state into a metastable state is observed for the organic cavity polariton device at room temperature via deviation from the Maxwell-Boltzmann statistics at k1 = 0 above the threshold. Thermalized polariton gases in organic systems at equilibrium hold substantial promise for designing room temperature polaritonic circuits, switches, and lattices for analog simulation. © 2022, CC BY-NC-SA.

关键词： Polariton

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Breast phantom design for X-ray phase-contrast imaging

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Research on Biomedical engineering 2019年第1期35卷 21-26页

作者： Badelli, Juliana do Carmo Ribeiro-Junior, Sebastião Antoniassi, Marcelo Conceição, Andre Luiz Coelho Graduate Program in Electrical and Computer Engineering - UTFPR Av. Sete de Setembro 3165 CuritibaParaná80230-901 Brazil Electrical Engineering Department Federal University of Paraná Rodovia BR-116 Km 98 no. 8813 Jardim das Américas CuritibaParaná81531-980 Brazil Physics Department Federal University of Technology - Paraná Av. Sete de Setembro 3165 CuritibaParaná80230-901 Brazil Deutsches Elektronen-Synchrotron DESY Notkestraße 85 Hamburg22607 Germany

Purpose: Breast cancer is one of the most diffuse diseases and its incidence rate is increasing. Mammography is the gold standard exam for screening breast cancer. Nevertheless, to provide better conditions for visualization and detection of tumors, in particular to young women, techniques exploiting the X-ray phase contrast to generate images have been studied and proposed for clinical use. As every imaging modality clinically implemented, the capabilities and limitations of an X-ray phase-contrast system dedicated to breast imaging should be evaluated by a phantom. Although for mammography, there are several commercial phantoms, for tomographic X-ray phase-contrast imaging systems dedicated to breast screening, they are absent. Therefore, this study aimed to design a breast phantom for application in phase-contrast computed tomography (PC-CT) imaging. Methods: A breast phantom dedicated to X-ray phase-contrast imaging was designed. The phantom has a cylindrical shape and is composed by PMMA, to mimic the breast of a young woman, with some inserts filled with tissue substitutes to normal and pathological breast tissues, such as ethanol and glycerol. These materials were chosen due to the similarity in the attenuation and scattering properties of normal and pathological human breast tissues. Results: A comparison between tomographic X-ray absorption imaging and tomographic X-ray phase-contrast imaging showed a significant increase in edges definition, even with materials with similar attenuation properties. Conclusion: The results of this work reinforce the need for dedicated phantoms to exploit the features of each imaging modality more realistic. In particular, the breast phantom–designed breast screening by PC-CT allows exploiting the features of this new imaging modality. © 2019, Sociedade Brasileira de Engenharia Biomedica.

关键词： Phantoms

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Development of teaching materials for improving motivation to learn electromagnetics using ict

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IEEJ Transactions on Fundamentals and Materials 2020年第4期140卷 171-178页

作者： Ohtaki, Yu 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

In this research, we have been developed teaching materials for electromagnetics that demonstrate theories using real-world actual applications (capacitors, coils, piezoelectric elements, Wireless Power Transfer(WPT), WiFi, direct-current motor, etc.) presented as animations and video data via Web services. Hypertext Markup Language (HTML) and JavaScript were used to create the Web services for teaching materials. Recently, the lack of academic ability of Japanese engineering course students has become a large social problem at Japanese higher education. In particular, in the field of electrical engineering education, the visualization and mathematical abilities of students have been declining remarkably. In addition, today's teaching materials for educational institutions in Japan tend to reply primarily on rote learning. However, we consider that rote learning is not the primary method for university education. We tested our new developed materials on students learning motivation of electromagnetics and evaluated their effectiveness with some questionnaires. It was clear that the new teaching method has effectiveness for increasing learning motivation of Electromagnetics. © 2020 The Institute of electrical Engineers of Japan.

关键词： Web services

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Set-based state estimation and fault diagnosis of linear discrete-time descriptor systems using constrained zonotopes

arXiv

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arXiv 2020年

作者： Rego, Brenner S. Raimondo, Davide M. Raffo, Guilherme V. Graduate Program in Electrical Engineering Federal University of Minas Gerais Belo Horizonte Brazil Department of Electrical Computer and Biomedical Engineering University of Pavia Pavia Italy Department of Electronics Engineering Federal University of Minas Gerais Belo Horizonte Brazil

This paper presents new methods for set-valued state estimation and active fault diagnosis of linear descriptor systems. The algorithms are based on constrained zonotopes, a generalization of zonotopes capable of describing strongly asymmetric convex sets, while retaining the computational advantages of zonotopes. Additionally, unlike other set representations like intervals, zonotopes, ellipsoids, paralletopes, among others, linear static constraints on the state variables, typical of descriptor systems, can be directly incorporated in the mathematical description of constrained zonotopes. Therefore, the proposed methods lead to more accurate results in state estimation in comparison to existing methods based on the previous sets without requiring rank assumptions on the structure of the descriptor system and with a fair trade-off between accuracy and efficiency. These advantages are highlighted in two numerical examples. Copyright © 2020, The Authors. All rights reserved.

关键词： Failure analysis

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Skin effect in Non-Hermitian systems with spin

arXiv

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arXiv 2024年

作者： Zhang, Wenna Hu, Yutao Zhang, Hongyi Liu, Xiang Shen, Yuecheng Veronis, Georgios Alù, Andrea Huang, Yin Luo, Wenchen School of Physics Central South University Changsha410083 China Shenzhen Institute for Quantum Science and Engineering Southern university of science and technology Shenzhen518055 China State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai200241 China School of Electrical Engineering and Computer Science Louisiana State University Baton RougeLA70803 United States Center for Computation and Technology Louisiana State University Baton RougeLA70803 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Physics Program Graduate Center City University of New York New YorkNY10026 United States

The skin effect, where bulk modes collapse into boundary modes, is a key phenomenon in topological non-Hermitian systems, has been predominantly studied in spinless systems. Recent studies illustrate the magnetic suppression of the first-order skin effect while ignoring spin. However, the physical significance of a magnetic field in non-Hermitian skin effect with spin remains elusive. Here, we systematically explore non-Hermitian spinful systems based on generalized Hatano-Nelson models with SU(2) gauge potential fields. In an open one-dimensional lattice, the spin-up and spin-down states can be uniquely separated and localized at the two boundaries without magnetic field. When an external magnetic field is applied, the skin effect exhibits a smooth transition from bidirectional to unidirectional. Remarkably, we demonstrate that the first-order skin effect can be anomalously induced by a magnetic field in a topologically trivial non-Hermitian spinful system without any skin effect at zero field. The direction of such magnetically induced skin modes can be controlled by simply changing the amplitude and polarity of the magnetic field. In addition, we demonstrate a transition between non-Bloch PT and anti-PT symmetries in the system, and uncover the spin-dependent mechanism of non-Bloch PT symmetry. Our results pave the way for the investigation of non-Hermitian skin effect with spin degrees of freedom. © 2024, CC BY.

关键词： Magnetic field effects

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Quantum simulation of an extended Dicke model with a magnetic solid

Communications Materials

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Communications Materials 2024年第1期5卷 1-9页

作者： Marquez Peraca, Nicolas Li, Xinwei Moya, Jaime M. Hayashida, Kenji Kim, Dasom Ma, Xiaoxuan Neubauer, Kelly J. Fallas Padilla, Diego Huang, Chien-Lung Dai, Pengcheng Nevidomskyy, Andriy H. Pu, Han Morosan, Emilia Cao, Shixun Bamba, Motoaki Kono, Junichiro Department of Physics and Astronomy Rice University HoustonTX United States Department of Physics California Institute of Technology PasadenaCA United States Applied Physics Graduate Program Smalley–Curl Institute Rice University HoustonTX United States Division of Applied Physics Graduate School of Engineering Hokkaido University Hokkaido Japan Department of Electrical and Computer Engineering Rice University HoustonTX United States Department of Physics International Center of Quantum and Molecular Structures and Materials Genome Institute Shanghai University Shanghai China Department of Physics and Center for Quantum Frontiers of Research and Technology National Cheng Kung University Tainan Taiwan Department of Chemistry Rice University HoustonTX United States Department of Physics I Kyoto University Kyoto Japan The Hakubi Center for Advanced Research Kyoto University Kyoto Japan PRESTO Japan Science and Technology Agency Saitama Japan Department of Physics Yokohama National University Yokohama Japan Department of Materials Science and NanoEngineering Rice University HoustonTX United States

The Dicke model describes the cooperative interaction of an ensemble of two-level atoms with a single-mode photonic field and exhibits a quantum phase transition as a function of light–matter coupling strength. Extending this model by incorporating short-range atom–atom interactions makes the problem intractable but is expected to produce new physical phenomena and phases. Here, we simulate such an extended Dicke model using a crystal of ErFeO3, where the role of atoms (photons) is played by Er3+ spins (Fe3+ magnons). Through terahertz spectroscopy and magnetocaloric effect measurements as a function of temperature and magnetic field, we demonstrated the existence of a novel atomically ordered phase in addition to the superradiant and normal phases that are expected from the standard Dicke model. Further, we elucidated the nature of the phase boundaries in the temperature–magnetic-field phase diagram, identifying both first-order and second-order phase transitions. These results lay the foundation for studying multiatomic quantum optics models using well-characterized many-body solid-state systems. © The Author(s) 2024.

关键词： Atoms

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Landau Polaritons in a Full-Dielectric Three-Dimensional Photonic-Crystal Cavity

Landau Polaritons in a Full-Dielectric Three-Dimensional Pho...

引用

Conference on Lasers and Electro-Optics (CLEO)

作者： Fuyang Tay Ali Mojibpour Shuang Liang Andrey Baydin Arash Ahmadivand Nicolas Marquez Peraca Hongjing Xu Geoff C. Gardner Michael J. Manfra David Hagenmüller Junichiro Kono Department of Electrical and Computer Engineering Rice University Houston Texas USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston Texas USA Department of Physics and Astronomy Purdue University West Lafayette IN USA Birck Nanotechnology Center Purdue University West Lafayette IN USA Smalley-Curl Institute Rice University Houston Texas USA Department of Physics and Astronomy Rice University Houston Texas USA Microsoft Quantum Purdue Purdue University West Lafayette IN USA School of Electrical and Computer Engineering Purdue University West Lafayette IN USA School of Materials Engineering Purdue University West Lafayette IN USA ISIS (UMR 7006) Université de Strasbourg and CNRS Strasbourg France Department of Materials Science and Nano Engineering Rice University Houston Texas USA

We fabricated a full-dielectric three-dimensional photonic-crystal cavity containing an ultrahigh-mobility two-dimensional electron gas. By applying a strong perpendicular magnetic field, we created Landau polaritons ... 详细信息

ISBN: (数字)9781957171050

ISBN: (纸本)9781665466660

关键词： Couplings HEMTs Laser modes Polaritons Magnetic fields Gas lasers MODFETs

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Energy Efficiency Project with Actions to Encourage the Rational and Sustainable Use of Electric Energy 19

Energy Efficiency Project with Actions to Encourage the Rati...

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19th IEEE International Conference on Environment and electrical engineering and 2019 IEEE Industrial and Commercial Power Systems Europe, EEEIC/I and CPS Europe 2019

作者： Lemos, G.C. Faria, A.F. Viajante, G.P. Domingues, E.G. Domingos, J.L. Silva, S.B. Souto, O.C.N. Velloso, E.J.F. Franca, J.L. Graduate Program in Sustainable Process Technology IFG Goiânia-GO Brazil Graduate Program in Electrical and Computer Eng. UFG Goiânia-GO Brazil Graduate Program in Sustainable Process Technology IFG Itumbiara-GO Brazil Anima Projects Engineering Commerce Goiânia-GO Brazil

ISBN: (纸本)9781728106526

This work is the critical analysis of an Energy Efficiency Project (EEP) developed in an educational institution. The case-study is based on several fronts that synthesize the perspective of sustainability in a Solar Tree, an equipment to compose the landscape furniture with the capacity to generate electricity from a renewable source, symbolizing the project and acting as motivating agent in maintenance, and also contributing to the design of new actions with this bias. In the other fronts, the work includes the quantification of the level of energy efficiency of a building, besides promoting the retrofit of the lighting system and the installation of a photovoltaic generation system, all focusing on the rational use of electric energy, whose results show that the energy saved and the reduction in the peak of demand, as well as the installation of the photovoltaic plant, will bring the installation closer to the concept of energy selfsufficiency. © 2019 IEEE.

关键词： Sustainable development

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