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Modeling Compositional Regression With Uncorrelated and Correlated Errors: A Bayesian Approach

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Journal of Data Science 2018年第2期16卷 221-249页

作者： Taciana K. O. Shimizu Francisco Louzada Adriano K. Suzuki Ricardo S. Ehlers Inter Program of Graduate Statistics Federal University of São Carlos and University of São Paulo Avenida Trabalhador São-carlense 400 São Carlos São Paulo Brazil Department of Applied Mathematics & Statistics Sciences Institute of Mathematics and Computers ICMC University of São Paulo Avenida Trabalhador São-carlense 400 São Carlos São Paulo Brazil

Compositional data consist of known compositions vectors whose components are positive and defined in the interval (0,1) representing proportions or fractions of a ＂whole＂. The sum of these components must be equal to one. Compositional data is present in different knowledge areas, as in geology, economy, medicine among many others. In this paper, we propose a new statistical tool for volleyball data, i.e., we introduce a Bayesian anal-ysis for compositional regression applying additive log-ratio (ALR) trans- formation and assuming uncorrelated and correlated errors. The Bayesian inference procedure based on Markov Chain Monte Carlo Methods (MCMC). The methodology is applied on an artificial and a real data set of volleyball.

关键词： Compositional data additive log-ratio transformation inference Bayesian correlated errors MCMC

Parallel block-preconditioned monolithic solvers for fluid-structure-interaction problems

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arXiv 2018年

作者： Jodlbauer, D. Langer, U. Wick, T. Doctoral Program on Computational Mathematics Johannes Kepler University Altenbergerstr. 69 LinzA-4040 Austria Johann Radon Institute for Computational and Applied Mathematics Austrian Academy of Sciences Altenbergerstr. 69 LinzA-4040 Austria Institut für Angewandte Mathematik Leibniz Universität Hannover Welfengarten 1 Hannover30167 Germany

In this work, we consider the solution of fluid-structure interaction problems using a monolithic approach for the coupling between fluid and solid subproblems. The coupling of both equations is realized by means of the arbitrary Lagrangian-Eulerian framework and a nonlinear harmonic mesh motion model. Monolithic approaches require the solution of large, ill-conditioned linear systems of algebraic equations at every Newton step. Direct solvers tend to use too much memory even for a relatively small number of degrees of freedom, and, in addition, exhibit superlinear grow in arithmetic complexity. Thus, iterative solvers are the only viable option. To ensure convergence of iterative methods within a reasonable amount of iterations, good and, at the same time, cheap preconditioners have to be developed. We study physics-based block preconditioners, which are derived from the block LDU-factorization of the FSI Jacobian, and their performance on distributed memory parallel computers in terms of two- and three-dimensional test cases permitting large deformations.65N30, 65M60, 49M15, 35Q74 Copyright © 2018, The Authors. All rights reserved.

关键词： Iterative methods

DtN-based mixed-dimensional coupling in aerospace structures 57

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DtN-based mixed-dimensional coupling in aerospace structures

57th Israel Annual Conference on Aerospace Sciences, IACAS 2017

作者： Ofir, Yoav Rabinovich, Daniel Givoli, Dan Technion - Israel Institute of Technology Interdepartmental Program of Applied Mathematics Haifa3200003 Israel Technion - Israel Institute of Technology Department of Aerospace Engineering Haifa3200003 Israel

A new computational approach for the mixed-dimensional modeling of time-harmonic waves in elastic aerospace structures is proposed. A two-dimensional (2D) structure is considered, which includes a part that is assumed to behave in a one-dimensional (1D) way. The 2D and 1D structural regions are discretized by using 2D and 1D Finite Element (FE) formulations. The hybrid model, if designed properly, is much more efficient than the standard 2D model taken for the entire problem. One important issue related to such hybrid 2D-1D models is the way the 2D-1D coupling is done, and the coupling error generated. Here, three closely-related coupling methods are considered - the DtN method, the CML method and an Iterative DtN technique. They are all based on the Dirichlet-to-Neumann (DtN) map associated with the 1D problem, on the interface. Direct application of these three methods results in low accuracy, as a recent study shows. Therefore, these methods are used here in conjunction with a Boundary Stress Recovery (BSR) technique, originally proposed by Hughes, which provides the same order of accuracy for the stress as for the primary variable. The performance of the three methods is demonstrated and they are compared via numerical examples. Conclusions are drawn on their relative merit.

关键词： One dimensional

Multigoal-oriented error estimates for non-linear problems

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arXiv 2018年

作者： Endtmayer, B. Langer, U. Wick, T. Doctoral Program on Computational Mathematics Johannes Kepler University Altenbergerstr. 69 LinzA-4040 Austria Johann Radon Institute for Computational and Applied Mathematics Austrian Academy of Sciences Altenbergerstr. 69 LinzA-4040 Austria Institut für Angewandte Mathematik Leibniz Universität Hannover Welfengarten 1 Hannover30167 Germany

In this work, we further develop multigoal-oriented a posteriori error estimation with two objectives in mind. First, we formulate goal-oriented mesh adaptivity for multiple functionals of interest for nonlinear problems in which both the Partial Differential Equation (PDE) and the goal functionals may be nonlinear. Our method is based on a posteriori error estimates in which the adjoint problem is used and a partition-of-unity is employed for the error localization that allows us to formulate the error estimator in the weak form. We provide a careful derivation of the primal and adjoint parts of the error estimator. The second objective is concerned with balancing the nonlinear iteration error with the discretization error yielding adaptive stopping rules for Newton's method. Our techniques are substantiated with several numerical examples including scalar PDEs and PDE systems, geometric singularities, and both nonlinear PDEs and nonlinear goal functionals. In these tests, up to six goal functionals are simultaneously controlled. Copyright © 2018, The Authors. All rights reserved.

关键词： Newton-Raphson method

A Lagrangian Method for Reactive Transport with Solid/Aqueous Chemical Phase Interaction i

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arXiv 2018年

作者： Schmidt, Michael J. Pankavich, Stephen D. Navarre-Sitchler, Alexis Benson, David A. Hydrologic Science and Engineering Program Department of Geology and Geological Engineering Colorado School of Mines GoldenCO80401 United States Department of Applied Mathematics and Statistics Colorado School of Mines GoldenCO80401 United States

A significant drawback of Lagrangian (particle-tracking) reactive transport models has been their inability to properly simulate interactions between solid and liquid chemical phases, such as dissolution and precipitation reactions. This work addresses that problem by implementing a mass-transfer algorithm between mobile and immobile sets of particles that allows aqueous species of reactant that are undergoing transport to interact with stationary solid species. This mass-transfer algorithm is demonstrated to solve the diffusion equation for an arbitrarily small level of diffusion and thus does not introduce any spurious mixing. The algorithm can be combined with random walks to simulate the desired total level of diffusion in a reactive transport system. Copyright © 2018, The Authors. All rights reserved.

关键词： Diffusion

Factor analysis for spectral estimation

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arXiv 2017年

作者： Andén, Joakim Singer, Amit Department of Mathematics Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States

Power spectrum estimation is an important tool in many applications, such as the whitening of noise. The popular multitaper method enjoys significant success, but fails for short signals with few samples. We propose a statistical model where a signal is given by a random linear combination of fixed, yet unknown, stochastic sources. Given multiple such signals, we estimate the subspace spanned by the power spectra of these fixed sources. Projecting individual power spectrum estimates onto this subspace increases estimation accuracy. We provide accuracy guarantees for this method and demonstrate it on simulated and experimental data from cryo-electron microscopy. Copyright © 2017, The Authors. All rights reserved.

关键词： Power spectrum

Monitoring of Uterus Electrical Activities using Electromyography in Stage I Induction Labor

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Journal of Physics: Conference Series 2019年第1期1179卷 012133-012133页

作者： Rhomadona, Shinta Wurdiana Melyana Nurul Widyawati Suryono, S Postgraduate Applied Science Midwifery program Poltekkes Kemenkes Semarang Indonesia Diploma III of Midwifery Stikes William Booth Surabaya Indonesia Lecturer Postgraduate Applied Science Midwifery program Poltekkes Kemenkes Semarang Indonesia Department of Physics Faculty of Science and Mathematics Diponegoro University Semarang Indonesia

Labor induction is one of the main contributors of serious complication among mothers and babies. Prolonged artificial uterus muscle contraction may result in uterus hyper stimulation. One method of prevention is using the abdomen palpation technique. However, its practice has so far been less effective, less accurate, time consuming, and somehow subjective, as it requires meticulousness of the examiner. The WHO recommends that laboring mothers using induction technique should continuously be monitored. Therefore, there is a need for a much more accurate measure using a monitoring instrument that is capable of recording contraction. The instrument is electromyography. This research analyzed uterus electrical activities in stage I labor induction. The method used was observing 10 respondents undergoing labor induction for their contraction, every 15 minutes for 10 minutes each using electromyography. Monitoring results were then analyzed for frequency, duration, interval, and action potential, and these were presented as a trend. Results show a trend of frequency, duration, interval, and action potential of uterus contraction in stage I labor, with successful induction showing increasing rhythm, while failed induction indicating constant rhythm. Mean frequency, duration, interval, and action potential is 5.30 time/10 minutes, 55.89 seconds, 4.12 minutes, and 1.64 V respectively. Meanwhile, the 3 mothers with failed induction have mean frequency of 1.64x/10 minute, mean contraction duration of 21.74 seconds, and mean interval of 7.40 minutes, and mean action potential of 1.18 V.

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Physiological response of premature infants due to the administration of pseudostem banana nest innovation to the incubator

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Journal of Physics: Conference Series 2019年第1期1179卷

作者： W Hapsari M N Widyawati S Suryono Diploma III of Midwifery Purwokerto PoltekkesKemenkes Semarang Indonesia Postgraduate Applied Science Midwifery Program PoltekkesKemenkes Semarang Indonesia Department of Physics Faculty of Science and Mathematics Diponegoro University Semarang Indonesia

In this study, innovation of banana pseudostem nest was conducted to assess the physiological response of premature infants due to the provision of pseudostem banana nest innovation in the incubator. This innovation is needed because premature babies need conditions that promote physiological response functions to increase body temperature, gain weight and assess changes in oxygen saturation. Unfortunately, so far there is no temperature stabilizer in the incubator, the incubator is made of electric and heating elements only so that some physical parameters cannot be accommodated with the incubator. Therefore, this paper proposes the innovation of pseudostem banana nest because it has a 400% water absorption level, a higher temperature stabilization on the fibers in commonly used materials. This study measures physiological responses. The research procedure begins with the manufacture of dried banana pseudostem ingredients, making pseudostem banana nest from banana midribs and coated with a cloth shaped like a hand containment. This research uses a quasi-experimental design method with pre-post test control group design. The sampling technique used was nonprobability sampling by consecutive sampling. A sample of 30 preterm infants was divided into 15 control group samples, 15 intervention group samples. Action procedure, the researcher treated the intervention group by placing nest pseudostem banana in the incubator until it surrounded the premature baby for three consecutive days. Measurements were made on parameters of body temperature, weight, oxygen saturation before and after intervention in the control group and intervention group for three consecutive days. The results of this study were obtained significant differences in body temperature, oxygen saturation before and after given nest pseudostem banana with a p-value of 0.001; 0.003. In this study, there were no significant differences in body weight before and after being given nest pseudostem banana with a

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Rational design of stealthy hyperuniform two-phase media with tunable order

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Physical Review E 2018年第2期97卷 023311-023311页

作者： Robert A. DiStasio, Jr. Ge Zhang Frank H. Stillinger Salvatore Torquato Department of Chemistry and Chemical Biology Cornell University Ithaca New York 14853 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Disordered stealthy hyperuniform materials are exotic amorphous states of matter that have attracted recent attention because of their novel structural characteristics (hidden order at large length scales) and physical properties, including desirable photonic and transport properties. It is therefore useful to devise algorithms that enable one to design a wide class of such amorphous configurations at will. In this paper, we present several algorithms enabling the systematic identification and generation of discrete (digitized) stealthy hyperuniform patterns with a tunable degree of order, paving the way towards the rational design of disordered materials endowed with novel thermodynamic and physical properties. To quantify the degree of order or disorder of the stealthy systems, we utilize the discrete version of the τ order metric, which accounts for the underlying spatial correlations that exist across all relevant length scales in a given digitized two-phase (or, equivalently, a two-spin state) system of interest. Our results impinge on a myriad of fields, ranging from physics, materials science and engineering, visual perception, and information theory to modern data science.

关键词： Pattern formation