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LLR measures the distance between observatories on Earth and retro-reflectors on Moon since 1969. In this paper, we estimate the Earth Rotation Parameters (ERP; terrestrial pole offsets, $x_p$ and $y_p$, and Earth rotation phase,…

Geophysics · Physics 2022-12-20 Vishwa Vijay Singh , Liliane Biskupek , Jürgen Müller , Mingyue Zhang

We describe a data reduction pipeline for VLBI astrometric observations of pulsars, implemented using the ParselTongue AIPS interface. The pipeline performs calibration (including ionosphere modeling), phase referencing with proper…

Astrophysics · Physics 2008-12-18 A. T. Deller , S. J. Tingay , W. Brisken

Rapid progress in machine learning and deep learning has enabled a wide range of applications in the electricity load forecasting of power systems, for instance, univariate and multivariate short-term load forecasting. Though the strong…

Machine Learning · Computer Science 2024-02-20 Yuqi Jiang , Yan Li , Yize Chen

Short Term Load forecasting in this paper uses input data dependent on parameters such as load for current hour and previous two hours, temperature for current hour and previous two hours, wind for current hour and previous two hours, cloud…

Neural and Evolutionary Computing · Computer Science 2009-12-08 Mrs. J. P. Rothe , Dr. A. K. Wadhwani , Dr. Mrs. S. Wadhwani

A recent study investigated the propagation of error in a Velocimetry-based Pressure (V-Pressure) field reconstruction problem by directly analyzing the properties of the pressure Poisson equation (Pan et al., 2016). In the present work, we…

Fluid Dynamics · Physics 2021-03-11 Matthew Faiella , Corwin G. J. Macmillan , Jared P. Whitehead , Zhao Pan

Global Positioning System (GPS) satellites broadcast at frequencies of 1,575.42 MHz (L1) and of 1,227.60 MHz (L2). The dispersive property of the ionosphere can be used to combine independent measurements at the two frequencies to estimate…

Astrophysics · Physics 2007-05-23 E. Ros , J. M. Marcaide , J. C. Guirado , E. Sardon , I. I. Shapiro

Pulsar's position, proper motion and parallax are important parameters in timing equations. It is a really challenging work to fit astrometric parameters accurately through pulsar timing, especially for pulsars that show irregular timing…

High Energy Astrophysical Phenomena · Physics 2020-07-08 Jie Liu , Zhen Yan , Zhi-Qiang Shen , Zhi-Peng Huang , Ru-Shuang Zhao , Ya-Jun Wu , Jian-Ping Yuan , Xin-Ji Wu

Very long baseline interferometry (VLBI) provides the highest-resolution images in astronomy. The sharpest resolution is nominally achieved at the highest frequencies, but as the observing frequency increases so too does the atmospheric…

A relativistic delay model for space very long baseline interferometry (hereafter SVLBI) observation of sources at infinite distance is derived. In SVLBI, where one station is on a spacecraft, the orbiting station's maximum speed in an…

Instrumentation and Methods for Astrophysics · Physics 2014-06-19 Shi-Long Liao , Zheng-Hong Tang , Zhao-Xiang Qi

Time series forecasting remains a central challenge problem in almost all scientific disciplines. We introduce a novel load forecasting method in which observed dynamics are modeled as a forced linear system using Dynamic Mode Decomposition…

Physics and Society · Physics 2021-07-13 Daniel Dylewsky , David Barajas-Solano , Tong Ma , Alexandre M. Tartakovsky , J. Nathan Kutz

We discuss the technique of Wide-field imaging as it applies to Very Long Baseline Interferometry (VLBI). In the past VLBI data sets were usually averaged so severely that the field-of-view was typically restricted to regions extending a…

Astrophysics · Physics 2009-10-31 M. A. Garrett , R. W. Porcas , A. Pedlar , T. W. B. Muxlow , S. T. Garrington

Accurate measurement of pulsar distances via astrometry using very long baseline interferometry enables the improvement of Galactic electron density distribution models, improving distance estimates for the vast majority of pulsars for…

Solar and Stellar Astrophysics · Physics 2011-02-11 A. T. Deller , S. J. Tingay , M. Bailes , J. E. Reynolds

Computation of gas dispersal in urban places or hilly grounds requires a large amount of computer time when addressed with conventional multidimensional models. Those are usually based on two-phase flow or Navier-Stokes equations. Different…

Analysis of PDEs · Mathematics 2021-01-13 Alexandre Chiapolino , Sébastien Courtiaud , Emmanuel Lapebie , Richard Saurel

The modern Very Long Baseline Interferometry (VLBI) relativistic delay model, as documented in the IERS Conventions refers to the time epoch when the signal passes one of two stations of an interferometer baseline (selected arbitrarily from…

Instrumentation and Methods for Astrophysics · Physics 2021-01-22 Oleg Titov , Alexei Melnikov , Yulia Lopez

We propose an alternative method to detect the secular aberration drift induced by the solar system acceleration due to the attraction to the Galaxy centre. This method is free of the individual radio source proper motion caused by…

Astrophysics of Galaxies · Physics 2018-03-14 O. Titov , H. Krásná

Mid-term electricity load forecasting (LF) plays a critical role in power system planning and operation. To address the issue of error accumulation and transfer during the operation of existing LF models, a novel model called error…

Machine Learning · Computer Science 2023-06-21 Liping Zhang , Di Wu , Xin Luo

When comparing modern fundamental reference frames in the radio (International Celestial Reference Frame) and optical (Gaia), a couple of bright radio reference sources appear to have very large radio-optical offsets, from tens up to…

Astrophysics of Galaxies · Physics 2025-01-14 S. Frey , O. Titov , A. Melnikov , S. Lambert

Astrometric positions of radio-emitting active galactic nuclei (AGNs) can be determined with sub-milliarcsec accuracy using very long baseline interferometry (VLBI). The usually small apparent proper motion of distant extragalactic targets…

In this document we layout a new method to achieve "bona fide" high precision Very-Long-Baseline-Interferometry (VLBI) astrometric measurements of frequency-dependent positions of celestial sources (even) in the high (mm-wavelength)…

Instrumentation and Methods for Astrophysics · Physics 2009-10-08 Richard Dodson , Maria J. Rioja

Stratospheric aerosols play an important role in the earth system and can affect the climate on timescales of months to years. However, estimating the characteristics of partially observed aerosol injections, such as those from volcanic…

Machine Learning · Computer Science 2024-09-12 J. Hart , I. Manickam , M. Gulian , L. Swiler , D. Bull , T. Ehrmann , H. Brown , B. Wagman , J. Watkins