Temporal Evolution

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R. Gafeira - One of the best experts on this subject based on the ideXlab platform.

  • Temporal Evolution of short-lived penumbral microjets
    Astronomy & Astrophysics, 2020
    Co-Authors: A. Siu-tapia, L. R. Bellot Rubio, D. Orozco Suárez, R. Gafeira
    Abstract:

    Context. Penumbral microjets are elongated jet-like brightenings observed in the chromosphere above sunspot penumbrae. They are transient events that last from a few seconds to several minutes and are thought to originate from magnetic reconnection processes. Previous studies have mainly focused on their morphological and spectral characteristics, and more recently on their spectropolarimetric signals during the maximum brightness stage. Studies addressing the Temporal Evolution of PMJs have also been carried out, but they are based on spatial and spectral time variations only. Aims. Here we investigate the Temporal Evolution of the polarization signals produced by short-lived PMJs (lifetimes $

  • Temporal Evolution of short lived penumbral microjets
    arXiv: Solar and Stellar Astrophysics, 2020
    Co-Authors: A Siutapia, L Bellot R Rubio, Orozco D Suarez, R. Gafeira
    Abstract:

    Context. Penumbral microjets are elongated jet-like brightenings observed in the chromosphere above sunspot penumbrae. They are transient events that last from a few seconds to several minutes and are thought to originate from magnetic reconnection processes. Previous studies have mainly focused on their morphological and spectral characteristics, and more recently on their spectropolarimetric signals during the maximum brightness stage. Studies addressing the Temporal Evolution of PMJs have also been carried out, but they are based on spatial and spectral time variations only. Aims. Here we investigate the Temporal Evolution of the polarization signals produced by short-lived PMJs (lifetimes $<$ 2 minutes) to infer how the magnetic field vector evolves in the upper photosphere and mid-chromosphere. Methods. We use fast-cadence spectropolarimetric observations of the Ca II 854.2 nm line taken with the CRisp Imaging Spectropolarimeter at the Swedish 1-m Solar Telescope. The weak-field approximation (WFA) is used to estimate the strength and inclination of the magnetic field vector. Results. The WFA reveals larger magnetic field changes in the upper photosphere than in the chromosphere during the PMJ maximum brightness stage. In the photosphere, the magnetic field inclination and strength undergo a transient increase for most PMJs, but in 25$\%$ of the cases the field strength decreases during the brightening. In the chromosphere, the magnetic field tends to be slightly stronger during the PMJs. Conclusions. The propagation of compressive perturbation fronts followed by a rarefaction phase in the aftershock region may explain the observed behavior of the magnetic field vector. The fact that such behavior varies among the analyzed PMJs could be a consequence of the limited Temporal resolution of the observations and the fast-evolving nature of the PMJs.

A. Siu-tapia - One of the best experts on this subject based on the ideXlab platform.

  • Temporal Evolution of short-lived penumbral microjets
    Astronomy & Astrophysics, 2020
    Co-Authors: A. Siu-tapia, L. R. Bellot Rubio, D. Orozco Suárez, R. Gafeira
    Abstract:

    Context. Penumbral microjets are elongated jet-like brightenings observed in the chromosphere above sunspot penumbrae. They are transient events that last from a few seconds to several minutes and are thought to originate from magnetic reconnection processes. Previous studies have mainly focused on their morphological and spectral characteristics, and more recently on their spectropolarimetric signals during the maximum brightness stage. Studies addressing the Temporal Evolution of PMJs have also been carried out, but they are based on spatial and spectral time variations only. Aims. Here we investigate the Temporal Evolution of the polarization signals produced by short-lived PMJs (lifetimes $

José A. R. Fonollosa - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of HMM Temporal Evolution for automatic speech recognition and verification
    Lecture Notes in Computer Science, 2006
    Co-Authors: Marta Casar, José A. R. Fonollosa
    Abstract:

    This paper proposes a double layer speech recognition and utterance verification system based on the analysis of the Temporal Evolution of HMM's state scores. For the lower layer, it uses standard HMM-based acoustic modeling, followed by a Viterbi grammar-free decoding step which provides us with the state scores of the acoustic models. In the second layer, these state scores are added to the regular set of acoustic parameters, building a new set of expanded HMMs. This new paremeter models the acoustic HMM's Temporal Evolution. Using the expanded set of HMMs for speech recognition a significant improvement in performance is achieved. Next, we will use this new architecture for utterance verification in a second opinion framework. We will consign to the second layer evaluating the reliability of decoding using the acoustic models from the first layer. An outstanding improvement in performance versus a baseline verification system has been achieved with this new approach.

  • TSD - Analysis of HMM Temporal Evolution for automatic speech recognition and verification
    Text Speech and Dialogue, 2006
    Co-Authors: Marta Casar, José A. R. Fonollosa
    Abstract:

    This paper proposes a double layer speech recognition and utterance verification system based on the analysis of the Temporal Evolution of HMM's state scores For the lower layer, it uses standard HMM-based acoustic modeling, followed by a Viterbi grammar-free decoding step which provides us with the state scores of the acoustic models In the second layer, these state scores are added to the regular set of acoustic parameters, building a new set of expanded HMMs This new paremeter models the acoustic HMM's Temporal Evolution Using the expanded set of HMMs for speech recognition a significant improvement in performance is achieved Next, we will use this new architecture for utterance verification in a ”second opinion” framework We will consign to the second layer evaluating the reliability of decoding using the acoustic models from the first layer An outstanding improvement in performance versus a baseline verification system has been achieved with this new approach.

Cuixiu Xiong - One of the best experts on this subject based on the ideXlab platform.

D. Orozco Suárez - One of the best experts on this subject based on the ideXlab platform.

  • Temporal Evolution of short-lived penumbral microjets
    Astronomy & Astrophysics, 2020
    Co-Authors: A. Siu-tapia, L. R. Bellot Rubio, D. Orozco Suárez, R. Gafeira
    Abstract:

    Context. Penumbral microjets are elongated jet-like brightenings observed in the chromosphere above sunspot penumbrae. They are transient events that last from a few seconds to several minutes and are thought to originate from magnetic reconnection processes. Previous studies have mainly focused on their morphological and spectral characteristics, and more recently on their spectropolarimetric signals during the maximum brightness stage. Studies addressing the Temporal Evolution of PMJs have also been carried out, but they are based on spatial and spectral time variations only. Aims. Here we investigate the Temporal Evolution of the polarization signals produced by short-lived PMJs (lifetimes $