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Conference on Lasers and Electro-Optics (CLEO)

作者： Yun Zhao Jae K. Jang Xingchen Ji Karl J. McNulty Yoshitomo Okawachi Michal Lipson Alexander L. Gaeta Department of Applied Physics and Applied Mathematics Columbia University New York NY USA Department of Electrical Engineering Columbia University New York NY USA

We theoretically and experimentally investigate the noise properties of four-wave mixing-based optical-parametric oscillators (OPOs) in silicon nitride microresonators. Such OPOs can operate at ultralow-noise levels a... 详细信息

ISBN: (纸本)9781957171258

关键词： Four wave mixing Oscillators Phase noise Phase shift Semiconductor lasers Silicon nitride

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IT-Security Risk Based Approach for Secure Operation of Distributed Data Platforms in Supply Chains

IT-Security Risk Based Approach for Secure Operation of Dist...

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IEEE International Conference on Industrial engineering and engineering Management

作者： Marvin Voß Jonas Kallisch Maxim Runge Tobias Theus Karl-Heinz Niemann Christoph Wunck Faculty I - Electrical Engineering and Information Technology University of Applied Sciences and Arts Hannover Germany Department of Engineering Section Electrical Engineering and Computer Science University of Applied Sciences Emden/Leer Germany Faculty of Mathematics Informatics and Statistics Ludwig Maximilian University Munich Germany

ISBN: (数字)9798350386097

ISBN: (纸本)9798350386103

This paper presents the development of a secure data platform designed to enhance operational efficiency and to facilitate cross-company collaboration within the manufacturing supply chain. The platform is designed to ease secure information exchange while maintaining the sovereignty of each participant, leveraging standardized security features and advanced technologies such as federated learning. Security measures are based on a comprehensive risk analysis, which methodically identifies, assesses, and mitigates potential threats. Moreover, federated learning models that are not transparent are utilized. This allows data owners to maintain control over sensitive information within the consortium. The described approach markedly enhances both security and operational collaboration across the industry, representing a crucial stride towards more integrated and efficient supply chain management in manufacturing.

关键词： Industries Supply chain management Federated learning Supply chains Collaboration Particle measurements Manufacturing Security Risk analysis Information exchange

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Revealing Actual Viscoelastic Relaxation Times in Capillary Breakup

arXiv

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arXiv 2025年

作者： Hu, Nan Hwang, Jonghyun Ruangkriengsin, Tachin Stone, Howard A. Department of Mechanical and Aerospace Engineering Princeton University NJ08544 United States Program in Applied and Computational Mathematics Princeton University NJ08544 United States

We use experiments and theory to elucidate the size effect in capillary breakup rheometry, where pre-stretching in the visco-capillary stage causes the apparent relaxation time to be consistently smaller than the actual value. We propose a method accounting for both the experimental size and the finite extensibility of polymers to extract the actual relaxation time. A phase diagram characterizes the expected measurement variability and delineates scaling law conditions. The results refine capillary breakup rheometry for viscoelastic fluids and advance the understanding of breakup dynamics across scales. Copyright © 2025, The Authors. All rights reserved.

关键词： Relaxation time

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Direct System Identification of Dynamical Networks with Partial Measurements: a Maximum Likelihood Approach

arXiv

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arXiv 2023年

作者： da Mata, João Victor Galvão Hansson, Anders Andersen, Martin S. Department of Applied Mathematics and Computer Science Technical University of Denmark Denmark Department of Electrical Engineering Linköping University Sweden

This paper introduces a novel direct approach to system identification of dynamic networks with missing data based on maximum likelihood estimation. Dynamic networks generally present a singular probability density function, which poses a challenge in the estimation of their parameters. By leveraging knowledge about the network’s interconnections, we show that it is possible to transform the problem into a more tractable form by applying linear transformations. This results in a nonsingular probability density function, enabling the application of maximum likelihood estimation techniques. Our preliminary numerical results suggest that when combined with global optimization algorithms or a suitable initialization strategy, we are able to obtain a good estimate of the dynamics of the internal systems. © 2023, CC BY.

关键词： Maximum likelihood estimation

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High-Gain Parametric Amplification On-Chip at Low Pump Powers

High-Gain Parametric Amplification On-Chip at Low Pump Power...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Yun Zhao Jae K. Jang Xingchen Ji Yoshitomo Okawachi Michal Lipson Alexander L. Gaeta Department of Applied Physics and Applied Mathematics Columbia University New York NY USA Department of Electrical Engineering Columbia University New York NY USA

We demonstrate a novel amplification scheme that yields high (30-dB), continuous-wave parametric amplification of weak signals using small-footprint microresonators at pump power levels (< 10 mW) compatible with ty... 详细信息

ISBN: (纸本)9781957171258

关键词： Erbium doped fiber amplifiers Frequency combs Lasers Microresonators Optical amplifiers Phase matching

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Generation of Low-Frequency Kerr Combs in Highly Compact Photonic Structures

Generation of Low-Frequency Kerr Combs in Highly Compact Pho...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Garrett Beals Yun Zhao Karl McNulty Swarnav Sanyal Sai Kanth Dacha Michal Lipson Alexander L. Gaeta Department of Applied Physics and Applied Mathematics Columbia University New York NY USA Department of Electrical Engineering Columbia University New York NY USA

We demonstrate on-chip single and multi-soliton generation in a 16-GHz free-spectral range compact spiral microresonator with a total area of 1 mm 2 . We measure the phase noise of states with different soliton number... 详细信息

ISBN: (纸本)9781957171258

关键词： Erbium doped fiber amplifiers Frequency combs Microwaves Phase noise Polarization control Tunable diode lasers

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Synergetic effects of multiple junction and surface hydroxyl in Cu/CuO/Cu2O/TiO2 heterostructures towards highly efficient photocatalysts for hydrogen generation

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Materials Science for Energy Technologies 2025年 8卷 131-142页

作者： Subagyo, Riki Anindika, Garcelina Rizky Aufkani, Afif Akmal Zhang, Lei Ardhyananta, Hosta Burhan, R.Y. Perry Nugraheni, Zjahra Vianita Akhlus, Syafsir Bahruji, Hasliza Prasetyoko, Didik Wellia, Diana Vanda Ivansyah, Atthar Luqman Arramel Kusumawati, Yuly Department of Chemistry Faculty of Science and Analytic Data Institut Teknologi Sepuluh Nopember Surabaya60111 Indonesia Center of Excellence Applied Physics and Chemistry Nano Center Indonesia Jl PUSPIPTEK South Tangerang Banten15314 Indonesia Department of Physics National University of Singapore Singapore117551 Singapore Department of Materials and Metallurgical Engineering Faculty of Industrial Technology and Systems Engineering Institut Teknologi Sepuluh Nopember Surabaya60111 Indonesia Centre of Advanced Material and Energy Science Universiti Brunei Darussalam Jalan Tungku Link BE 1410 Brunei Department of Chemistry Faculty of Mathematics and Natural Sciences Universitas Andalas Padang25163 Indonesia Master Program in Computational Science Faculty of Mathematics and Natural Science Institut Teknologi Bandung Jalan Ganesha No. 10 Bandung40132 Indonesia Instrumentation and Computational Physics Research Group Department of Physics Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha No.10 West Java Bandung40132 Indonesia

The implementation of titanium dioxide (TiO2) as a photocatalyst material in hydrogen (H2) evolution reaction (HER) has embarked renewed interest in the past decade. Rapid electron-hole pairs recombination and wide band gap of a photo-sensitive material of TiO2 are detrimental toward the targeted catalytical reaction. In this study, we present the rational design, fabrication, photocatalytic performance of TiO2-Cu/CuO/Cu2O heterostructures (CuTi) using viable chemical reduction method. The Z-scheme and S-scheme are succesfully generated across the TiO2/CuO/Cu2O interfaces, while the Schottky junction arises on the Cu perimeters. This is evidenced from the blue shifted about 0.3 eV of Cu 2p core level determined by using X-ray photoemission spectroscopy (XPS), in combination with the formation of inverse V-shape of the Mott-Schottky plots. In addition, we find that Cu/CuO/Cu2O facilitates photon absorption range up to the visible region. The multiple heterojunction and the large number of OHsurface enhanced charge carrier transfer are associated to the suppression of photoluminescence (PL) intensity, high surface hydroxyl (OHsurface) density in CuTi probed by XPS, and fast electron transfer based on the electrochemical measurements. The presence of OHsurface inhibits the recombination of electron. A significant H2 photogeneration rate enhancement is achieved when an optimized 5 wt% Cu/CuO/Cu2O concentration is used on TiO2 to achieve 7,157.19 μmol·g−1 (1,789.30 μmol·g−1·h−1). Based on this finding, zero emission energy innitiative could be materialized under multiple heterojunctions in photocatalytic process is beneficial for enhancing the H2 production. © 2025 The Authors

关键词： Titanium dioxide

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Online Stochastic Gradient Methods Under Sub-Weibull Noise and the Polyak-Łojasiewicz Condition

Online Stochastic Gradient Methods Under Sub-Weibull Noise a...

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IEEE Conference on Decision and Control

作者： Seunghyun Kim Liam Madden Emiliano Dall’Anese Department of Applied Mathematics University of Colorado Boulder Department of Electrical Computer and Energy Engineering and with the Department of Applied Mathematics University of Colorado Boulder

ISBN: (数字)9781665467612

ISBN: (纸本)9781665467629

This paper focuses on the online gradient and proximal-gradient methods with stochastic gradient errors. In particular, we examine the performance of the online gradient descent method when the cost satisfies the Polyak-Łojasiewicz (PL) inequality. We provide bounds in expectation and in high probability (that hold iteration-wise), with the latter derived by leveraging a sub-Weibull model for the errors affecting the gradient. The convergence results show that the instantaneous regret converges linearly up to an error that depends on the variability of the problem and the statistics of the sub-Weibull gradient error. Convergence results are then provided for the online proximal-gradient method, under the assumption that the composite cost satisfies the proximal-PL condition. In the case of static costs, we provide new bounds for the regret incurred by these methods when the gradient errors are modeled as sub-Weibull random variables. Illustrative simulations are provided to corroborate the technical findings.

关键词： Gradient methods Costs Stochastic processes Estimation Cost function Random variables Task analysis

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Generalized epidemic model incorporating non-Markovian infection processes and waning immunity

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Physical Review E 2023年第1期108卷 014405-014405页

作者： Qihui Yang Joan Saldaña Caterina Scoglio Department of Electrical and Computer Engineering Kansas State University Manhattan 66506 Kansas USA Department of Computer Science Applied Mathematics and Statistics Universitat de Girona Girona 17003 Catalonia Spain

The Markovian approach, which assumes exponentially distributed interinfection times, is dominant in epidemic modeling. However, this assumption is unrealistic as an individual's infectiousness depends on its viral load and varies over time. In this paper, we present a Susceptible-Infected-Recovered-Vaccinated-Susceptible epidemic model incorporating non-Markovian infection processes. The model can be easily adapted to accurately capture the generation time distributions of emerging infectious diseases, which is essential for accurate epidemic prediction. We observe noticeable variations in the transient behavior under different infectiousness profiles and the same basic reproduction number R0. The theoretical analyses show that only R0 and the mean immunity period of the vaccinated individuals have an impact on the critical vaccination rate needed to achieve herd immunity. A vaccination level at the critical vaccination rate can ensure a very low incidence among the population in the case of future epidemics, regardless of the infectiousness profiles.

关键词： Epidemic evolution Epidemic growth Population dynamics

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Unsupervised multi-scale diagnostics

arXiv

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arXiv 2024年

作者： Lapo, Karl Ichinaga, Sara M. Kutz, J. Nathan Department of Atmospheric and Cryospheric Sciences University of Innsbruck Innsbruck6020 Austria Department of Applied Mathematics University of Washington SeattleWA98195 United States Departments of Applied Mathematics and Electrical and Computer Engineering University of Washington SeattleWA United States

The unsupervised and principled diagnosis of multi-scale data is a fundamental obstacle in modern scientific problems from, for instance, weather and climate prediction, neurology, epidemiology, and turbulence. Multi-scale data is characterized by a combination of processes acting along multiple dimensions simultaneously, spatiotemporal scales across orders of magnitude, non-stationarity, and/or invariances such as translation and rotation. Existing methods are not well-suited to multiscale data, usually requiring supervised strategies such as human intervention, extensive tuning, or selection of ideal time periods. We present the multi-resolution Coherent Spatio-Temporal Scale Separation (mrCOSTS), a hierarchical and automated algorithm for the diagnosis of coherent patterns or modes in multi-scale data. mrCOSTS is a variant of Dynamic Mode Decomposition which decomposes data into bands of spatial patterns with shared time dynamics, thereby providing a robust method for analyzing multi-scale data. It requires no training but instead takes advantage of the hierarchical nature of multi-scale systems. We demonstrate mrCOSTS using complex multi-scale data sets that are canonically difficult to analyze: 1) climate patterns of sea surface temperature, 2) electrophysiological observations of neural signals of the motor cortex, and 3) horizontal wind in the mountain boundary layer. With mrCOSTS, we trivially retrieve complex dynamics that were previously difficult to resolve while additionally extracting hitherto unknown patterns of activity embedded in the dynamics, allowing for advancing the understanding of these fields of study. This method is an important advancement for addressing the multi-scale data which characterize many of the grand challenges in science and *** Codes 37-04 (primary) 37N10, 37N25, 86-08 (secondary) © 2024, CC BY.

关键词： Hierarchical systems

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