265 research outputs found
Evolution of small-scale magnetic elements in the vicinity of granular-size swirl convective motions
Advances in solar instrumentation have led to a widespread usage of time
series to study the dynamics of solar features, specially at small spatial
scales and at very fast cadences. Physical processes at such scales are
determinant as building blocks for many others occurring from the lower to the
upper layers of the solar atmosphere and beyond, ultimately for understanding
the bigger picture of solar activity. Ground-based (SST) and space-borne
(Hinode) high-resolution solar data are analyzed in a quiet Sun region
displaying negative polarity small-scale magnetic concentrations and a cluster
of bright points observed in G-band and Ca II H images. The studied region is
characterized by the presence of two small-scale convective vortex-type plasma
motions, one of which appears to be affecting the dynamics of both, magnetic
features and bright points in its vicinity and therefore the main target of our
investigations. We followed the evolution of bright points, intensity
variations at different atmospheric heights and magnetic evolution for a set of
interesting selected regions. A description of the evolution of the
photospheric plasma motions in the region nearby the convective vortex is
shown, as well as some plausible cases for convective collapse detected in
Stokes profiles.Comment: 9 figure
Reconfiguración asimétrica de un manipulador paralelo de 3-gdl
In this paper an asymmetric reconfigurable parallel manipulator is presented. Asymmetric configurations are obtained by modifying the angle between each of the kinematic chains. Thanks to the reconfiguration proposal significant improvement of the manipulator performance can be obtained with respect to a Delta-type parallel robot. The computation of the best condition number is obtained, the results show that by using the redundancy, all the performance indices that depend on the Jacobian matrix can be improved as well.En este trabajo se presenta un manipulador paralelo reconfigurable asimétrico. Al modificar los ángulos de cada una de las cadenas cinemáticas pueden obtenerse configuraciones asimétricas. Gracias a la reconfiguración propuesta pueden generarse mejoras significativas del desempeño del manipulador, con respecto a un robot paralelo tipo Delta. El cálculo del mejor número de condición es obtenido, los resultados muestran que usando la redundancia todos los Ãndices de desempeño que dependen de la matriz Jacobiana pueden ser mejorados también
Spatial distribution and statistical properties of small-scale convective vortex-like motions in a quiet Sun region
High-resolution observations of a quiet Sun internetwork region taken with
the Solar 1-m Swedish Telescope in La Palma are analyzed. We determine the
location of small-scale vortex motions in the solar photospheric region by
computing the horizontal proper motions of small-scale structures on time
series of images. These plasma convectively-driven swirl motions are associated
to: (1) downdrafts (that have been commonly explained as corresponding to sites
where the plasma is cooled down and hence returned to the interior below the
visible photospheric level), and (2) horizontal velocity vectors converging
into a central point. The sink cores are proved to be the final destination of
passive floats tracing plasma flows towards the center of each vortex. We
establish the occurrence of these events to be 1.4 x 10^(-3) and 1.6 x 10^(-3)
vortices Mm^(-2) min^(-1) respectively for two time series analyzed here.Comment: 8 pages, 6 figures. Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
An Open Source Quantitative Evaluation Framework for Automatic Video Summarization Algorithms
The creation, consumption, and manipulation of video play a central role in everyday life as the amount of video data is growing at an exponential rate. Video summarization consists on producing a condensed output from a video that allows humans to rapidly understand and browse the content of the original source. Although there are several evaluation approaches proposed in the literature, multiple challenges make the quantitative evaluation of a summarization a complex process. In this paper we present a completely open video summarization evaluation framework that is compatible with existing datasets and published results. Standard metrics are considered and a new metric that captures unbalanced-class video summarization evaluation is proposed. Two legacy datasets are integrated in a standard format. Finally, new quantitative results based on already published algorithms are presented.Sociedad Argentina de Informática e Investigación Operativ
An Open Source Quantitative Evaluation Framework for Automatic Video Summarization Algorithms
The creation, consumption, and manipulation of video play a central role in everyday life as the amount of video data is growing at an exponential rate. Video summarization consists on producing a condensed output from a video that allows humans to rapidly understand and browse the content of the original source. Although there are several evaluation approaches proposed in the literature, multiple challenges make the quantitative evaluation of a summarization a complex process. In this paper we present a completely open video summarization evaluation framework that is compatible with existing datasets and published results. Standard metrics are considered and a new metric that captures unbalanced-class video summarization evaluation is proposed. Two legacy datasets are integrated in a standard format. Finally, new quantitative results based on already published algorithms are presented.Sociedad Argentina de Informática e Investigación Operativ
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