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Forward and inverse energy cascade and fluctuation relation in fluid turbulence adhere to Kolmogorov's refined similarity hypothesis

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arXiv 2023年

作者： Yao, H. Yeung, P.K. Zaki, T.A. Meneveau, C. Department of Mechanical Engineering Institute for Data Intensive Engineering & Science Johns Hopkins University United States Department of Aerospace Engineering and Mechanical Engineering Georgia Institute of Technology United States Mechanical Engineering & IDIES Johns Hopkins University United States

We study fluctuations of the local energy cascade rate Φ in turbulent flows at scales () in the inertial range. According to the Kolmogorov refined similarity hypothesis (KRSH), relevant statistical properties of Φ should depend on ϵ, the viscous dissipation rate locally averaged over a sphere of size , rather than on the global average dissipation. However, the validity of KRSH applied to Φ has not yet been tested from data. Conditional averages such as 〈Φ|ϵ〉 as well as of higher-order moments are measured from Direct Numerical Simulations data, and results clearly adhere to the predictions from KRSH. Remarkably, the same is true when considering forward (Φ > 0) and inverse (Φ © 2023, CC BY.

关键词： Turbulence

FedMonitor: An Implementation Architecture for Monitoring of Resources and Events'Notifications on Federated Cloud Computing Infrastructures 4

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FedMonitor: An Implementation Architecture for Monitoring of...

4th International Conference on Emerging Trends in Networks and Computer Communications, ETNCC 2024

作者： Adetiba, Emmanuel Nnaji, Uche Wejin, John S. Ojesanmi, Festus Akanle, Matthew B. Ajayi, Priscilla O. Sweetwiliams, Faith O. Thakur, Surendra C. Adebiyi, Ezekiel F. Department of Electrical and Information Engineering and Covenant Applied Ota Nigeria HRA Institute for Systems Science Durban University of Technology Durban South Africa Covenant University Department of Computer and Information Science & CApIC-ACE Ota Nigeria Covenant University Department of Electrical and Information Engineering & CApIC-ACE Jalingo Nigeria Tareba State University Department of Computer Science Jalingo Nigeria Ota Nigeria Covenant University & CApIC-ACE Covenant University Department of Electrical and Information Engineering Ota Nigeria Covenant University Center for Systems and Information Services & CApIC-ACE Ota Nigeria Durban University of Technology e-Skills Co-Laboratory Department of Information Technology and KZN Durban4001 South Africa Covenant University Ogun State Ota Nigeria Makerere University African Center of Excellence in Bioinformatics & Data Intensive Science Kampala10218 Uganda

ISBN: (纸本)9798350353266

In the evolving landscape of cloud computing, federated cloud infrastructures present unique challenges and opportunities for resource and application monitoring. Monitoring the diverse array of cloud resources and applications within a federated cloud environment is crucial for delivering consistent Quality of Service (QoS) and continuous oversight across various cloud applications and infrastructure. Despite the various successes documented in the literature on multi-cloud monitoring, existing frameworks have not fully explored or provided enough insights into centralized monitoring of resources, applications, and network devices in a federated cloud environment. This paper introduces FedMonitor, an implementation architecture designed to enhance the monitoring and notification capabilities in federated cloud environments by building on the theoretical ideals in our earlier work (i.e. FEDARGOS-V1). FedMonitor leverages Prometheus and Grafana to crawl, manage and visualize metrics from diverse software services, hardware resources, and network devices within a federated cloud environment. The results demonstrate hat FedMonitor improves the effectiveness of resource and application monitoring in federated cloud environments. © 2024 IEEE.

关键词： Cloud platforms

Conceptual Method of Temperature Sensation in Bionic Hand by Extraordinary Perceptual Phenomenon

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Journal of Bionic engineering 2021年第6期18卷 1344-1357页

作者： Saeed Bahrami Moqadam Ahamd Saleh Asheghabadi Farzaneh Norouzi Hamed Jafarzadeh Ali Khosroabadi AfshinAlagheband Ghazal Bangash Negar Morovatdar Jing Xu State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing100084China Medical University of Mashhad 13131–99137MashhadIran Center for Computational and Data Intensive Science and Engineering(CDISE) Skolkovo Institute of Science and Technology(Skoltech)Moscow121205Russia Department of Mechanical Engineering Ferdowsi UniversityMashhad***Iran Department of Electrical Engineering Ferdowsi UniversityMashhad***Iran Department of Computer Engineering Ferdowsi UniversityMashhad***Iran Clinical Research Unit Imam Reza HospitalMashhad University of Medical Sciences13131–99137MashhadIran

Lack of temperature sensation of myoelectric prosthetic hand limits the daily activities of *** this end,a noninvasive temperature sensation method is proposed to train amputees to sense temperature with psychophysical sensory *** this study,22 healthy participants took part besides 5 amputee *** duration time of the study was 31 days with five test steps according to the Leitner *** adjustable temperature mug and a Peltier were used to change the temperature of the water/phantom digits to induce temperature to ***,to isolate the surroundings and show colors,a Virtual Reality(VR)glass was *** statistical results conducted are based on the response of participants with questionnaire *** Chi-square tests,it is concluded that participants answer the experiment significantly correctly using the Leitner technique(P value<0.05).Also,by applying the“Repeated Measures ANOVA”,it is noticed that the time of numbness felt by participants had significant(P value<0.001)*** could remember lowest and highest temperatures significantly better than other temperatures(P value<0.001);furthermore,the well-trained amputee participant practically using the prosthesis with 72.58%could identify object’s temperature with only once time experimenting the color temperature.

关键词： Temperature perceptions Leitner learning technique Classical conditioning Psychophysical sensory substitution Extraordinary perceptual phenomenon Bionic hand prosthesis

A DIFFERENTIABLE MODEL OF NUCLEIC ACID DYNAMICS

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arXiv 2024年

作者： Krueger, Ryan K. Engel, Megan C. Hausen, Ryan Brenner, Michael P. School of Engineering and Applied Sciences Harvard University CambridgeMA United States Department of Biological Sciences University of Calgary CalgaryAB Canada Institute for Data Intensive Engineering and Science Johns Hopkins University BaltimoreMD United States Department of Physics Harvard University CambridgeMA United States

Developing physics-based models for molecular simulation requires fitting many unknown parameters to experimental datasets of diverse properties. Fitting such diverse data is typically carried out piecemeal, resulting in a "zoo" of disconnected but highly related models. Here, we leverage recently developed methods for computing low-variance gradient estimates with automatic differentiation to facilitate the extensible, reproducible, and transparent fitting of the physics-based DNA model oxDNA. We demonstrate simultaneous fitting to structural, mechanical, and thermodynamic data using a variety of techniques, including enhanced sampling, external forcing, cluster-move Monte Carlo schemes, and micro- and millisecond timescales, and fit oxDNA to a range of target properties, such as twist-stretch couplings and duplex melting temperatures. We also demonstrate how gradients can serve as an efficient means of sensitivity analysis through which we uncover the surprising importance of the cross-stacking interaction in oxDNA. Though grounded in oxDNA, this work provides a framework for extensible, community-driven force field development more generally that will yield rapidly improved models and subsequent physical insights for systems ranging from RNA to protein to their interactions with inorganic materials. Copyright © 2024, The Authors. All rights reserved.

关键词： Sensitivity analysis

A study of first-passage time minimization via Q-learning in heated gridworlds

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arXiv 2021年

作者： Larchenko, Maria A. Osinenko, P. Yaremenko, G. Palyulin, V.V. Center for Computational and Data-intensive Science and Engineering Skolkovo Institute of Science and Technology Moscow121205 Russia

Optimization of first-passage times is required in applications ranging from nanobots navigation to market trading. In such settings, one often encounters unevenly distributed noise levels across the environment. We extensively study how a learning agent fares in 1- and 2- dimensional heated gridworlds with an uneven temperature distribution. The results show certain bias effects in agents trained via simple tabular Q-learning, SARSA, Expected SARSA and Double Q-learning. While high learning rate prevents exploration of regions with higher temperature, low enough rate increases the presence of agents in such regions. The discovered peculiarities and biases of temporal-difference-based reinforcement learning methods should be taken into account in real-world physical applications and agent design. Copyright © 2021, The Authors. All rights reserved.

关键词： Reinforcement learning

Non-adaptive and two-stage coding over the Z-channel

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arXiv 2022年

作者： Lebedev, Alexey Lebedev, Vladimir Vorobyev, Ilya Deppe, Christian Kharkevich Institute for Information Transmission Problems Russian Academy of Sciences Moscow Russia Center for Computational and Data-Intensive Science and Engineering Skolkovo Institute of Science and Technology Moscow Russia Institute for Communications Engineering Department of Electrical and Computer Engineering Technical University of Munich Munich Germany

In this paper, we developed new coding strategies for the Z-channel. In particular, we look at the case with two-stage encoding. In this case, the encoder uses noiseless feedback once and adjusts the further encoding strategy based on the previous partial output of the channel. Nevertheless, the developed codes improve the known results with full feedback for small length and 1 error. A tool for the two-stage strategy is the development of a new optimality condition for non-adaptive codes. Copyright © 2022, The Authors. All rights reserved.

关键词： Signal encoding

HistoMSC: Density and topology analysis for AI-based visual annotation of histopathology whole slide images

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Computers in Biology and Medicine 2025年 190卷 109991-109991页

作者： Ahmad, Zahoor Al-Thelaya, Khaled Alzubaidi, Mahmood Joad, Faaiz Gilal, Nauman Ullah Mifsud, William Boughorbel, Sabri Pintore, Giovanni Gobbetti, Enrico Schneider, Jens Agus, Marco Division of Information and Computing Technology College of Science and Engineering Hamad Bin Khalifa University Qatar Foundation Doha Qatar Kite Pharma Santa MonicaCA United States Visual and Data-intensive Computing CRS4 Italy Qatar Computing Research Institute Hamad Bin Khalifa University Qatar Foundation Doha Qatar

We introduce an end-to-end framework for the automated visual annotation of histopathology whole slide images. Our method integrates deep learning models to achieve precise localization and classification of cell nuclei with spatial data aggregation to extend classes of sparsely distributed nuclei across the entire slide. We introduce a novel and cost-effective approach to localization, leveraging a U-Net architecture and a ResNet-50 backbone. The performance is boosted through color normalization techniques, helping achieve robustness under color variations resulting from diverse scanners and staining reagents. The framework is complemented by a YOLO detection architecture, augmented with generative methods. For classification, we use context patches around each nucleus, fed to various deep architectures. Sparse nuclei-level annotations are then aggregated using kernel density estimation, followed by color-coding and isocontouring. This reduces visual clutter and provides per-pixel probabilities with respect to pathology taxonomies. Finally, we use Morse–Smale theory to generate abstract annotations, highlighting extrema in the density functions and potential spatial interactions in the form of abstract graphs. Thus, our visualization allows for exploration at scales ranging from individual nuclei to the macro-scale. We tested the effectiveness of our framework in an assessment by six pathologists using various neoplastic cases. Our results demonstrate the robustness and usefulness of the proposed framework in aiding histopathologists in their analysis and interpretation of whole slide images. © 2025 The Authors

关键词： Image annotation

Analysis of inertial-range intermittency in forward and inverse cascade regions in isotropic turbulence

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arXiv 2025年

作者： Yao, H. Schnaubelt, M. Lubonja, A. Medvedev, D. Hao, Y. Wang, M. Lemson, G. Burns, R. Szalay, A.S. Yeung, P.K. Eyink, G. Zaki, T.A. Meneveau, C. Institute for Data Intensive Engineering and Science Johns Hopkins University BaltimoreMD United States Department of Mechanical Engineering Johns Hopkins University BaltimoreMD United States Department of Computer Science Johns Hopkins University BaltimoreMD United States Department of Mechanical Engineering Massachusetts Institute of Technology CambridgeMA United States Schools of Aerospace Engineering and Mechanical Engineering Georgia Institute of Technology AtlantaGA United States Department of Applied Mathematics and Statistics Johns Hopkins University BaltimoreMD United States Department of Physics and Astronomy Johns Hopkins University BaltimoreMD United States

In order to test the hypothesis that inverse cascade regions in turbulent flows might exhibit more Gaussian noise-like and less intermittent small-scale statistics compared to the overall statistics, in this work we measure degrees of small-scale intermittency separately in regions of forward and inverse cascade. The local energy cascade rate (Φ) at length scale () is defined using the scale-integrated Kolmogorov-Hill (KH) equation. The sign of Φ indicates the local cascading direction, with Φ > 0 representing forward cascade of kinetic energy to smaller scales and Φ . Our findings reveal that transverse velocity increments display approximately the same degree of non-Gaussianity and intermittency, regardless of whether they occur in forward or inverse cascade regions. The only noticeable difference is observed for longitudinal velocity increments that display strong negative skewness in regions of forward cascade compared to small positive skewness in regions of inverse cascade. We repeat the analysis for filtered velocity gradient tensor elements at scale and obtain similar results, except that the skewness of its longitudinal elements is slightly negative even in regions of inverse cascade. The result shows that subtle differences exist between unfiltered velocity increments at scale and gradients of filtered velocity, specifically in regions of inverse cascade where the additional small-scale information contained in velocity increments is necessary to establish inverse energy flux from small to large scales. The analysis is based on isotropic turbulence data (Reλ ∼ 1,250) available from the public Johns Hopkins Turbulence databases, JHTDB v2.0. This refactored system is based on the Zarr storage format, while data access is based on the "virtual sensor" approach, enabled by a Python backend package (Giverny) that replaces the legacy SQL storage and SOAP Web Services-based approaches. Information about the new system as well as sample Python notebooks are descri

关键词： Gaussian distribution

Benchmarks of Cuda-Based GMRES Solver for Toeplitz and Hankel Matrices and Applications to Topology Optimization of Photonic Components

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Computational Mathematics and Modeling 2021年第4期32卷 438-452页

作者： Minin, Iu. B. Matveev, S.A. Fedorov, M.V. Zacharov, I.E. Rykovanov, S.G. Skoltech Center for Computational and Data-Intensive Science and Engineering Skolkovo Institute of Science and Technology Moscow Russian Federation Fryazino Branch of Kotel’nikov Institute of Radio-Engineering and Electronics of Russian Academy of Sciences Moscow Fryazino Russian Federation Faculty of Computational Mathematics and Cybernetics Lomonosov Moscow State University Moscow Russian Federation Marchuk Institute of Numerical Mathematics Russian Academy of Sciences Moscow Russian Federation Sirius University of Science and Technology Krasnodar Krai Sochi Russian Federation

Generalized Minimal Residual Method (GMRES) was benchmarked on many types of GPUs for solving linear systems based on dense and sparse matrices. However, there are still no GMRES implementation benchmarks on Tesla V100 compared to GTX 1080 Ti ones or even for Toeplitz-like matrices. The introduced software consists of a Python module and a C++ library which enable to manage streams for concurrent computations of separated linear systems on a GPU (and GPUs). The GMRES solver is parallelized for running on a NVIDIA GPGPU accelerator. The parallelization efficiency is explored when GMRES is applied to solve (Helmholtz equation) linear systems based on the use of Green’s Function Integral Equation Method (GFIEM) for computing electric field distribution in the design domain. The proposed implementation shew the maximal speedup of 55 (t¯=0.017s) and of 125 (t¯=0.77s) for 1024 × 1024 (on GTX 1080 Ti) and 8192 × 8192 (on Tesla V100) dense Toeplitz matrices generated from GFIEM. 1024 × 1024 resolution provides accuracy 6.1% that can be acceptable according to testing and demonstrating on gradient computations and topology optimization. We open up possibilities for robust topology optimization of passive photonic integrated components. That has the advantage, e. g., of faster and more accurate designing photonic components on a PC without a supercomputer. © 2022, Springer science+Business Media, LLC, part of Springer Nature.

关键词： CUDA C++ GMRES GPU Helmholtz equation parallelization performance Python module Toeplitz-like matrix topology optimization