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Context. Determining stellar characteristics such as the radius, the mass or the age is crucial when studying stellar evolution, exoplanetary systems or characterising stellar populations in the Galaxy. Asteroseismology is the golden path…

太阳与恒星天体物理 · 物理学 2015-01-28 Gaël Buldgen , Daniel Roy Reese , Marc-Antoine Dupret , Réza Samadi

Increasing the light scattering efficiency of nanostructured materials is becoming an active field of research both in fundamental science and commercial applications. In this context, the challenge is to use inexpensive organic materials…

光学 · 物理学 2021-07-05 Johannes S. Haataja , Gianni Jacucci , Lukas Schertel , Silvia Vignolini

The polarization of the Mg II h & k resonance lines is the result of the joint action of scattering processes and the magnetic field induced Hanle, Zeeman, and magneto-optical effects, thus holding significant potential for the diagnostic…

太阳与恒星天体物理 · 物理学 2024-09-10 Hao Li , Tanausú del Pino Alemán , Javier Trujillo Bueno

The method of solar magnetic field calibration for the filter-based magnetograph is normally the linear calibration method under weak-field approximation that cannot generate the strong magnetic field region well due to the magnetic…

太阳与恒星天体物理 · 物理学 2021-02-10 Jingjing Guo , Xianyong Bai , Yuanyong Deng , Hui Liu , Jiaben Lin , Jiangtao Su , Xiao Yang , Kaifan Ji

We study the photometric properties of stars in the data archive of the Sloan Digital Sky Survey (SDSS), the prime aim being to understand the photometric calibration over the entire data set. It is confirmed that the photometric…

太阳与恒星天体物理 · 物理学 2015-05-19 Masataka Fukugita , Naoki Yasuda , Mamoru Doi , James E. Gunn , Donald G. York

Existing diffusion-based methods for inverse problems sample from the posterior using score functions and accept the generated random samples as solutions. In applications that posterior mean is preferred, we have to generate multiple…

机器学习 · 计算机科学 2024-10-10 Zhipeng Xue , Penghao Cai , Xiaojun Yuan , Xiqi Gao

An efficient and accurate image reconstruction algorithm for ultrasound tomography (UST) is described and demonstrated, which can recover accurate sound speed distribution from acoustic time series measurements made in soft tissue. The…

数值分析 · 数学 2021-11-17 Ashkan Javaherian , Ben Cox

Field level statistics, such as the minimum spanning tree (MST), have been shown to be a promising tool for parameter inference in cosmology. However, applications to real galaxy surveys are challenging, due to the presence of small scale…

宇宙学与河外天体物理 · 物理学 2025-05-13 Krishna Naidoo , Ofer Lahav

The formation of sunspots requires the concentration of magnetic flux near the surface. The negative magnetic pressure instability (NEMPI) might be a possible mechanism for accomplishing this, but it has mainly been studied in simple…

太阳与恒星天体物理 · 物理学 2018-01-24 Barbara Perri , Axel Brandenburg

High resolution spectro-polarimetric observations of a sunspot light bridge by Hinode, reveal small-scale inhomogeneities in the magnetic field and velocity. These inhomogeneities arise as a consequence of a weak, secondary lobe in the…

太阳与恒星天体物理 · 物理学 2015-10-28 Rohan E. Louis

This paper investigates the inverse scattering problems using sampling methods with near field measurements. The near field measurements appear in two classical inverse scattering problems: the inverse scattering for obstacles and the…

数值分析 · 数学 2021-07-02 Xiaodong Liu , Shixu Meng , Bo Zhang

Causal inference problems often involve continuous treatments, such as dose, duration, or frequency. However, identifying and estimating standard dose-response estimands requires that everyone has some chance of receiving any level of the…

统计方法学 · 统计学 2026-01-28 Kyle Schindl , Shuying Shen , Edward H. Kennedy

We consider the inverse problem of recovering a potential by measuring the response at a point to a source located at the same point and then varying the point on the surface of a sphere. This is a similar to the inverse back-scattering…

偏微分方程分析 · 数学 2014-03-10 Rakesh , Gunther Uhlmann

Generated images of score-based models can suffer from errors in their spatial means, an effect, referred to as a color shift, which grows for larger images. This paper investigates a previously-introduced approach to mitigate color shifts…

机器学习 · 计算机科学 2023-11-30 Katherine Deck , Tobias Bischoff

Magnetic fields on the surface of the Sun and stars in general imprint or modify the polarization state of the electromagnetic radiation that is leaving from the star. The inference of solar/stellar magnetic fields is performed by…

太阳与恒星天体物理 · 物理学 2016-11-23 Jaime de la Cruz Rodríguez , Michiel van Noort

In this paper, a new inversion model for 2D microwave imaging is introduced by means of a convenient rewriting of the usual Lippmann Schwinger integral scattering equation. Such model is derived by decomposing the Greens function and the…

信号处理 · 电气工程与系统科学 2021-03-01 Martina T. Bevacqua , Tommaso Isernia

Many computational problems involve solving a linear system of equations, although only a subset of the entries of the solution are needed. In inverse problems, where the goal is to estimate unknown parameters from indirect noisy…

数值分析 · 数学 2026-01-13 Daniela Calvetti , Nuutti Hyvönen , Ville Kolehmainen , Erkki Somersalo

Researchers often impute continuous variables under an assumption of normality, yet many incomplete variables are skewed. We find that imputing skewed continuous variables under a normal model can lead to bias; the bias is usually mild for…

统计方法学 · 统计学 2017-07-19 Paul T. von Hippel

We formulate and study a general family of (continuous-time) stochastic dynamics for accelerated first-order minimization of smooth convex functions. Building on an averaging formulation of accelerated mirror descent, we propose a…

最优化与控制 · 数学 2017-07-20 Walid Krichene , Peter L. Bartlett

Obtaining valid treatment effect inference remains a challenging problem when dealing with numerous instruments and non-sparse control variables. In this paper, we propose a novel ridge regularization-based instrumental variables method for…

计量经济学 · 经济学 2025-10-17 Xiduo Chen , Xingdong Feng , Antonio F. Galvao , Yeheng Ge