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We propose a new, nonparametric approach to learning and representing transition dynamics in Markov decision processes (MDPs), which can be combined easily with dynamic programming methods for policy optimisation and value estimation. This…

Machine Learning · Computer Science 2012-06-22 Steffen Grunewalder , Guy Lever , Luca Baldassarre , Massi Pontil , Arthur Gretton

Small scale processes are thought to be important for the dynamics of the solar atmosphere. While numerical resolution fundamentally limits their inclusion in MHD simulations, real observations at the same nominal resolution should still…

Solar and Stellar Astrophysics · Physics 2022-06-23 Thore E. Moe , Tiago M. D. Pereira , Mats Carlsson

Magnetic Resonance Elastography (MRE) has become an essential tool in assessing the mechanical properties of soft tissues in-vivo, prompting significant progress in new inversion algorithms. This creates a need for a benchmarking framework…

Numerical Analysis · Mathematics 2026-04-06 Yashasvi Verma , Jakob Schattenfroh , Ingolf Sack , Silvia Budday , Paul Steinmann , Luca Heltai

Stochastic mirror descent (SMD) is a fairly new family of algorithms that has recently found a wide range of applications in optimization, machine learning, and control. It can be considered a generalization of the classical stochastic…

Optimization and Control · Mathematics 2019-04-04 Navid Azizan , Babak Hassibi

The physical interpretation of spectropolarimetric observations of lines of neutral helium, such as those of the 10830 A multiplet, represents an excellent opportunity for investigating the magnetism of plasma structures in the solar…

Astrophysics · Physics 2007-05-23 A. Asensio Ramos , J. Trujillo Bueno

An accurate measurement of magnetic field is very important for understanding the formation and evolution of solar magnetic fields. Currently there are two types of solar magnetic field measurement instruments: the filter-based…

Solar and Stellar Astrophysics · Physics 2023-10-10 Mei Zhang , Haocheng Zhang , Chengqing Jiang

X-ray polarimetry promises to deliver unique information about the geometry of the inner accretion flow of astrophysical black holes and the nature of matter and electromagnetism in and around neutron stars. In this paper, we discuss the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 F. Kislat , B. Clark , M. Beilicke , H. Krawczynski

Sunspots are prominent manifestations of the solar cycle and provide key constraints for understanding its operation. Also, knowing internal structure of sunspots allows us to gain insights on the energy transport in strong magnetic fields…

Solar and Stellar Astrophysics · Physics 2010-03-29 R. Wenzel , S. V. Berdyugina , D. M. Fluri , J. Arnaud , A. Sainz-Dalda

Sea surface temperature (SST) is an essential climate variable that can be measured via ground truth, remote sensing, or hybrid model methodologies. Here, we celebrate SST surveillance progress via the application of a few relevant…

Atmospheric and Oceanic Physics · Physics 2023-06-19 Albert Larson , Ali Shafqat Akanda

The accuracy of Milne-Eddington (ME) inversions, used to retrieve the magnetic field vector, depends upon the signal-to-noise ratio (SNR) of the spectro-polarimetric observations. The SNR in real observations varies from pixel to pixel,…

Solar and Stellar Astrophysics · Physics 2015-05-19 Sanjay Gosain , Sanjiv Kumar Tiwari , P. Venkatakrishnan

In space weather studies and forecasting we employ magnetohydrodynamic (MHD) simulations which can provide rather accurate reconstruction of the solar wind dynamics and its evolution. However, all MHD simulations are restricted by the input…

Solar and Stellar Astrophysics · Physics 2023-06-14 G. M. Shaifullah , J. Magdalenic , C. Tiburzi , I. Jebaraj , E. Samara , P. Zucca

We analyze the spectral properties of driven, supersonic compressible magnetohydrodynamic (MHD) turbulence obtained via high-resolution numerical experiments, for application to understanding the dynamics of giant molecular clouds. Via…

Astrophysics · Physics 2009-11-07 Jason G. Vestuto , Eve C. Ostriker , James M. Stone

In two previous papers (Price & Monaghan 2004a,b) (papers I,II) we have described an algorithm for solving the equations of Magnetohydrodynamics (MHD) using the Smoothed Particle Hydrodynamics (SPH) method. The algorithm uses dissipative…

Astrophysics · Physics 2009-11-13 D. J. Price , J. J. Monaghan

In this paper we discuss recent applications of the Smoothed Particle Hydrodynamics (SPH) method to the simulation of supersonic turbulence in the interstellar medium, as well as giving an update on recent algorithmic developments in…

Instrumentation and Methods for Astrophysics · Physics 2010-02-26 Daniel J. Price , Christoph Federrath

Different methods for simulating the effects of spatial resolution on magnetic field maps are compared, including those commonly used for inter-instrument comparisons. The investigation first uses synthetic data, and the results are…

Solar and Stellar Astrophysics · Physics 2011-06-27 KD Leka , G. Barnes

Spectroscopic and spectropolarimetric observations, which rely on the Doppler effect, only provide access to the line-of-sight component of the solar plasma velocity (vz). However, many dynamic processes in the solar atmosphere involve…

Solar and Stellar Astrophysics · Physics 2026-03-30 H. Vila Crespo , J. M. Borrero , I. Milić , G. Vigeesh , A. Asensio Ramos

The structure of the solar chromosphere is believed to be governed by magnetic fields, even in quiet-Sun regions that have a relatively weak photospheric field. During the past decade inversion methods have emerged as powerful tools for…

Solar and Stellar Astrophysics · Physics 2015-06-05 Jaime de la Cruz Rodríguez , Hector Socas-Navarro , Mats Carlsson , Jorrit Leenaarts

An example of full solution of the inverse scattering problem on the half line is presented. For this purpose, a simple analytically solvable model system (Morse potential) is used, which is expected to be a reasonable approximation to a…

Quantum Physics · Physics 2015-01-20 Matti Selg

longitudinal magnetic field often suffers the saturation effect in strong magnetic field region when the measurement performs in a single-wavelength point and linear calibration is adopted. In this study, we develop a method that can judge…

Solar and Stellar Astrophysics · Physics 2021-05-05 Haiqing Xu , Suo Liu , Jiangtao Su , Yuanyong Deng , Andrei Plotnikov , Xianyong Bai , Jie Chen , Xiao Yang , Jingjing Guo , Xiaofan Wang , Yongliang Song

We applied machine learning to the entire data history of ESO's High Accuracy Radial Velocity Planet Searcher (HARPS) instrument. Our primary goal was to recover the physical properties of the observed objects, with a secondary emphasis on…

Solar and Stellar Astrophysics · Physics 2024-12-13 Vojtěch Cvrček , Martino Romaniello , Radim Šára , Wolfram Freudling , Pascal Ballester
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