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A fast multi-fidelity method with uncertainty quantification for complex data correlations: Application to vortex-induced vibrations of marine risers

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arXiv 2020年

作者： Meng, Xuhui Wang, Zhicheng Fan, Dixia Triantafyllou, Michael Karniadakis, George Em Division of Applied Mathematics Brown University ProvidenceRI02906 United States Department of Mechanical Engineering Massachusetts Institute Technology CambridgeMA02139 United States Sea Grant College Program Massachusetts Institute of Technology CambridgeMA02139 United States

We develop a fast multi-fidelity modeling method for very complex correlations between high- and low-fidelity data by working in modal space to extract the proper correlation function. We apply this method to infer the amplitude of motion of a flexible marine riser in cross-flow, subject to vortex-induced vibrations (VIV). VIV are driven by an absolute instability in the flow, which imposes a frequency (Strouhal) law that requires a matching with the impedance of the structure;this matching is easily achieved because of the rapid parametric variation of the added mass force. As a result, the wavenumber of the riser spatial response is within narrow bands of uncertainty. Hence, an error in wavenumber prediction can cause significant phase-related errors in the shape of the amplitude of response along the riser, rendering correlation between low- and high-fidelity data very complex. Working in modal space as outlined herein, dense data from low-fidelity data, provided by the semi-empirical computer code VIVA, can correlate in modal space with few high-fidelity data, obtained from experiments or fully-resolved CFD simulations, to correct both phase and amplitude and provide predictions that agree very well overall with the correct shape of the amplitude response. We also quantify the uncertainty in the prediction using Bayesian modeling and exploit this uncertainty to formulate an active learning strategy for the best possible location of the sensors providing the high fidelity measurements. © 2020, CC BY.

关键词： Fluid structure interaction

Multifunctional Resonant Wavefront-Shaping Meta-Optics Based on Multilayer and Multi-Perturbation Nonlocal Metasurfaces

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arXiv 2020年

作者： Malek, Stephanie C. Overvig, Adam C. Alù, Andrea Yu, Nanfang Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 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 YorkNY10016 United States

Photonic devices rarely provide both elaborate spatial control and sharp spectral control over an incoming wavefront. In optical metasurfaces, for example, the localized modes of individual meta-units govern the wavefront shape over a broad bandwidth, while nonlocal lattice modes extended over many unit cells support high quality-factor resonances. Here, we experimentally demonstrate nonlocal dielectric metasurfaces in the near-infrared that offer both spatial and spectral control of light, realizing metalenses focusing light exclusively over a narrowband resonance while leaving off-resonant frequencies unaffected. Our devices attain this functionality by supporting a quasi-bound state in the continuum encoded with a spatially varying geometric phase. We leverage this capability to experimentally realize a versatile platform for multispectral wavefront shaping where a stack of metasurfaces, each supporting multiple independently controlled quasi-bound states in the continuum, molds the optical wavefront distinctively at multiple wavelengths and yet stay transparent over the rest of the spectrum. Such a platform is scalable to the visible for applications in augmented reality and transparent displays. Copyright © 2020, The Authors. All rights reserved.

关键词： Wavefronts

CellBiAge: Improved single-cell age classification using data binarization

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Cell Reports 2023年第12期42卷 113500页

作者： Yu, Doudou Li, Manlin Linghu, Guanjie Hu, Yihuan Hajdarovic, Kaitlyn H. Wang, An Singh, Ritambhara Webb, Ashley E. Molecular Biology Cell Biology and Biochemistry Graduate Program Brown University Providence 02912 RI United States Data Science Institute Brown University Providence 02912 RI United States Neuroscience Graduate Program Brown University Providence 02912 RI United States Department of Applied Mathematics & Statistics Johns Hopkins University Baltimore 21218 MD United States Department of Computer Science Brown University Providence 02912 RI United States Center for Computational Molecular Biology Brown University Providence 02912 RI United States Department of Molecular Biology Cell Biology and Biochemistry Brown University Providence 02912 RI United States Center on the Biology of Aging Brown University Providence 02912 RI United States Carney Institute for Brain Science Brown University Providence 02912 RI United States Center for Translational Neuroscience Brown University Providence 02912 RI United States

Aging is a major risk factor for many diseases. Accurate methods for predicting age in specific cell types are essential to understand the heterogeneity of aging and to assess rejuvenation strategies. However, classifying organismal age at single-cell resolution using transcriptomics is challenging due to sparsity and noise. Here, we developed CellBiAge, a robust and easy-to-implement machine learning pipeline, to classify the age of single cells in the mouse brain using single-cell transcriptomics. We show that binarization of gene expression values for the top highly variable genes significantly improved test performance across different models, techniques, sexes, and brain regions, with potential age-related genes identified for model prediction. Additionally, we demonstrate CellBiAge's ability to capture exercise-induced rejuvenation in neural stem cells. This study provides a broadly applicable approach for robust classification of organismal age of single cells in the mouse brain, which may aid in understanding the aging process and evaluating rejuvenation methods. © 2023 The Authors

关键词： aging brain CP: Cell biology hypothalamus machine learning single-cell RNA-seq

NUMERICAL ANALYSIS OF ELLIPTIC HEMIVARIATIONAL INEQUALITIES FOR SEMIPERMEABLE MEDIA

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Journal of Computational mathematics 2019年第4期37卷 506-523页

作者： Weimin Han Ziping Huang Cheng Wang Wei Xu Program in Applied Mathematical and Computational Sciences (A MCS)& Department of Mathematics University of Iowa Iowa City IA 522/2 USA School of Mathematical Sciences Tongji University Shanghai 200092 China Tongji Zhejiang College J taxing 314051 China School of Mathematical Sciences Tojigji University Shanghai 200092 China School of Mathematical Sciences Tongji University Shanghai 200092 China Tongji Zhejiang College Jiaxing 314051 China

In this paper, we consider elliptic hemivariational inequalities arising in applications in semipermeable media. In its general form, the model includes both interior and boundary semipermeability terms. Detailed study is given on the hemivariational inequality in the case of isotropic and homogeneous semipermeable media. Solution existence and uniqueness of the problem are explored. Convergence of the Galerkin method is shown under the basic solution regularity available from the existence result. An optimal order error estimate is derived for the linear finite element solution under suitable solution regularity assumptions. The results can be readily extended to the study of more general hemivariational inequalities for non-isotropic and heterogeneous semipermeable media with interior semipermeability and/or boundary semiperrneability. Numerical examples are presented to show the performance of the finite element approximations;in particular, the theoretically predicted optimal first order convergence in H' norm of the linear element solutions is clearly observed.

关键词： Hemivariational inequality Interior semipermeability Boundary semipermeability Finite element method Error estimate

IN VITRO POPULATION GROWTH OF HUMAN GLIOBLASTOMAS: REAL PATIENTS AND CURVE FITTING

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Hematology, Transfusion and Cell Therapy 2025年 47卷 103807-103807页

作者： Diego Samuel Rodrigues Letícia Fernanda Alves João Frederico da Costa Azevedo Meyer Moníze Valéria Ramos da Silva Natália Barreto Catarina Raposo Faculdade de Tecnologia Universidade Estadual de Campinas (UNICAMP) Limeira SP Brazil PhD Program in Applied Mathematics Universidade Estadual de Campinas (UNICAMP) Campinas SP Brazil Instituto de Matemática Estatística e Computação Científica Universidade Estadual de Campinas (UNICAMP) Campinas SP Brazil Faculdade de Ciências Farmacêuticas Universidade Estadual de Campinas (UNICAMP) Campinas SP Brazil

Introduction/Justification For more than a century, a variety of ordinary differential equation growth models have been used to describe and predict the proliferation of human malignancies. Indeed, in the field of mathematical oncology, the growth of cell populations over time is typically represented by sigmoidal functions, such as logistic or Gompertz curves and their generalizations. These models are particularly focused on understanding and predicting the proliferation of cancer cells, including those from human glioblastomas, which can be very aggressive brain tumors with a survival rate of less than two years. Objectives This research examines in vitro cell cultures of five lines of human glioblastoma using curve fitting and numerical parameter estimation of real datasets to separately describe the growth profile of all these cell populations lineages over time. Materials and Methods Cell culture experiments were performed in the Advanced Therapeutics Laboratory at FCF-UNICAMP. These included a well-established human glioblastoma cell line (NG97) and four other glioblastoma cell lines derived from clinical patients designated N07, C03, L09 and J01. Twelve repeated time series of experiments were collected for each cell line. Cell counting was performed daily on days 1 to 6. The drda R package was used for curve fitting of the measured data aiming to determine the intrinsic growth rate and other parameters for each of the five cell lines. The 5-parameter generalized logistic curve was used, and all the resulting models were analyzed under statistical criteria such as the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC). Results Curve fitting analysis revealed significant diversity in the population growth of different cell lines. The drda R package proved to be highly effective in capturing these different behaviors and the unique sigmoidal shapes associated with them. Notably, the population growth of NG97 cells showed the least

关键词： Generalized Logistic Function Glioblastomas Mathematical Oncology

Hyper-molecules: On the representation and recovery of dynamical structures, with application to flexible macro-molecular structures in cryo-EM

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arXiv 2019年

作者： Lederman, Roy R. Andén, Joakim Singer, Amit Department of Statistics and Data Science Yale University New HavenCT United States Center for Computational Mathematics Flatiron Institute New YorkNY United States Department of Mathematics and Program in Applied and Computational Mathematics Princeton University PrincetonNJ United States

Cryo-electron microscopy (cryo-EM), the subject of the 2017 Nobel Prize in Chemistry, is a technology for determining the 3-D structure of macromolecules from many noisy 2-D projections of instances of these macromolecules, whose orientations and positions are unknown. The molecular structures are not rigid objects, but flexible objects involved in dynamical processes. The different conformations are exhibited by different instances of the macromolecule observed in a cryo-EM experiment, each of which is recorded as a particle image. The range of conformations and the conformation of each particle are not known a priori;one of the great promises of cryo-EM is to map this conformation space. Remarkable progress has been made in determining rigid structures from homogeneous samples of molecules in spite of the unknown orientation of each particle image and significant progress has been made in recovering a few distinct states from mixtures of rather distinct conformations, but more complex heterogeneous samples remain a major challenge. We introduce the "hyper-molecule" framework for modeling structures across different states of heterogeneous molecules, including continuums of states. The key idea behind this framework is representing heterogeneous macromolecules as high-dimensional objects, with the additional dimensions representing the conformation space. This idea is then refined to model properties such as localized heterogeneity. In addition, we introduce an algorithmic framework for recovering such maps of heterogeneous objects from experimental data using a Bayesian formulation of the problem and Markov chain Monte Carlo (MCMC) algorithms to address the computational challenges in recovering these high dimensional hyper-molecules. We demonstrate these ideas in a prototype applied to synthetic data. Copyright © 2019, The Authors. All rights reserved.

关键词： Medical imaging

The role of information systems towards the success of the family planning program: a literature review

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Journal of Physics: Conference Series 2020年第1期1524卷

作者： K Yusika M N Widyawati S Suryono Master of Applied Science in Midwifery Poltekkes Kemenkes Semarang Indonesia Postgraduate Applied Science Midwifery Program Poltekkes Kemenkes Semarang Indonesia Department of Physics Faculty of Science and Mathematics Universitas Diponegoro Semarang Indonesia

Family planning is an arrangement aimed at forming a prosperous family by limiting the number of births by using contraception. Birth control can reduce unwanted pregnancies, high-risk pregnancies, and prevent maternal death. One of the information systems that has been used in the health world is the immunization day reminder and management of hospital activities. The reminder system is effective as a reminder of the immunization schedule. This wireless technology helps health workers quickly and practically in health services. The use of information systems in family planning programs can support the success of family planning, one of which is to reduce the number of family planning failures and the proper use of family planning. This study uses the PRISMA protocol guidelines. The referenced journals come from various sources that have good publishing credibility and can be accounted for. This study discusses how information systems play a role in the success of family planning programs. The method used in this article is a systematic literature review. This study discusses a number of journals by examining in detail in preliminary studies, research objects, performance indicators, variables and methods applied So as to briefly learn the benefits of information systems as a tool for the success of family planning in midwifery services.

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Parameters Estimation Of Rayleigh Distribution In Survival Analysis On Type Ii Censored Data Using The Bayesian Method

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Journal of Physics: Conference Series 2020年第1期1503卷

作者： Erma Elviana Joko Purwadi Mathematics Study Program Faculty of Applied Science and Technology Ahmad Dahlan University Yogyakarta

This research aims to determine the estimation of Rayleigh's distribution parameters on the data survival analysis of type II of tuberculosis patients. The method used in this research is the Bayesian method to perform estimate parameters. The process estimation parameter using the Bayesian method requires information from the likelihood function and the prior distribution. The prior distribution used was the prior distribution of Jeffreys. In this study, estimates of Rayleigh's distribution parameters were applied in the survival analysis data of tuberculosis sufferers. And the value of estimated parameters in patients with tuberculosis acquired θ = 0.001097324 and the changes of the survival value decreased near to zero.

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Forcing a (κ)-like principle to hold at a weakly compact cardinal

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arXiv 2019年

作者： Cody, Brent Gitman, Victoria Lambie-Hanson, Chris Virginia Commonwealth University Department of Mathematics and Applied Mathematics 1015 Floyd Avenue RichmondVA23284 United States City University of New York CUNY Graduate Center Mathematics Program 365 Fifth Avenue New YorkNY10016 United States

Hellsten [Hel03a] proved that when κ is Π1 n-indescribable, the n- club subsets of κ provide a filter base for the Π1 n-indescribability ideal, and hence can also be used to give a characterization of Π1 n-indescribable sets which resembles the definition of stationarity: a set S ⊂ k is Π1 n-indescribable if and only if S ∩ C 6= Ø for every n-club C ⊂ ≠. By replacing clubs with n-clubs in the definition of (κ), one obtains a (κ)-like principle n(κ), a version of which was first considered by Brickhill and Welch [BW]. The principle n(κ) is consistent with the Π1 n-indescribability of but inconsistent with the Π1 n+1-indescribability of κ. By generalizing the standard forcing to add a (κ)-sequence, we show that if κ is κ+-weakly compact and GCH holds then there is a cofinality-preserving forcing extension in which κ remains +- weakly compact and 1(κ) holds. If is Π1 2-indescribable and GCH holds then there is a cofinality-preserving forcing extension in which is κ+-weakly compact, 1(κ) holds and every weakly compact subset of κ has a weakly compact proper initial segment. As an application, we prove that, relative to a Π1 2-indescribable cardinal, it is consistent that is κ+-weakly compact, every weakly compact subset of has a weakly compact proper initial segment, and there exist two weakly compact subsets S0 and S1 of such that there is no β MSC Codes 03E55, 03E35 Copyright © 2019, The Authors. All rights reserved.

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