Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/3920
2016-05-02T08:47:35ZSpace Weather Prediction System providing forecasts and alerts on solar flares and SEP events
http://hdl.handle.net/2117/86097
Space Weather Prediction System providing forecasts and alerts on solar flares and SEP events
García Rigo, Alberto; Nuñez, Marlon; Qahwaji, Rami; Ashamari, Omar W; Jiggens, Piers; Pérez, Gustau; Hernández Pajares, Manuel; Hilgers, Alain
A web-based prototype system for predicting Solar Flares and Solar Energetic Particle (SEP) events for its use by space launcher operators or any interested user has been implemented. The main goal of this system, called SEPsFLAREs, is to provide warnings/predictions with forecast horizons from 48 hours before to a few hours before to the SEP peak flux, and duration predictions. The module responsible for predicting solar flares, the SF_PMod, is based on the well-known ASAP flare predictor [T. Colak & R. Qahwaji, Automated solar activity prediction: A hybrid computer platform using machine learning and solar imaging for automated prediction of solar flares, Space Weather, 7 (S06001), 2009], which learns rules by using machine learning techniques on SDO/SOHO solar images to automatically detect sunspots, classify them based on the McIntosh classification system, and predict C-, M-, and X-class flares with forecast horizon from 6 h to 48 h. Regarding the performance of the flare predictor, the 24-hour forecast horizon was found to provide the best performance: the Probability of Detection (POD), False Alarm Ratio (FAR) and True Skill Statistics estimations were 63.8%, 99.0% and 0.5 respectively for predicting X-class flares; and 88.7%, 87.0% and 0.59 respectively, for predicting M-class flares. The module responsible for predicting the SEP onset and occurrence, the SEP_OO_PMod, is based on the well-known UMASEP predictor [M. Núñez, Predicting solar energetic proton events (E > 10 MeV), Space Weather, 9 (S07003), 2011], which performs X-ray and proton flux correlations to find the first symptoms of future well- and poorly-connected SEP events. The SEP_OO_PMod also provides a Warning Tool which is able to warn about potential proton enhancements (including SEP events) from flare predictions. Regarding the performance of the SEP_OO_PMod, it was validated taking into account all 129 SEP events from January 1994 to June 2014 and obtained a POD of 86.82%, a FAR of 25.83%, and an Average Warning Time (AWT) of 3.93 h. Regarding the evaluation of the Warning Tool, the best performance, obtained with a set of user-defined parameters, were a POD of 58.3%, FAR of 90.1%, and AWT of 23.1 h. The module responsible for predicting SEP peak and duration, the SEP_FID_PMod, identifies the parent solar flare associated to an observed/predicted SEP, simulates the radial propagation of the predicted shock on a representative IMF structure (i.e. a static Parker Spiral), and predicts the SEP peak and duration. The SEP_FID_PMod, validated taking into account all 129 SEP events from January 1994 to June 2014, obtained a Mean Absolute Error (MAE) of SEP peak time predictions of 11.3 h, a MAE of peak intensity predictions of 0.53 in log10 units of pfu, and a MAE of SEP end time predictions of 28.8 h. The SEPsFLAREs system also acquires data for solar flares nowcasting (including GSFLAD proxy and SISTED detector from MONITOR’s ESA-funded project; [Hernández-Pajares, M., A. García-Rigo, J.M. Juan, J. Sanz, E. Monte and A. Aragón-Ángel (2012), GNSS measurement of EUV photons flux rate during strong and mid solar flares. Space Weather, Volume 10, Issue 12, doi:10.1029/2012SW000826] and [García-Rigo, A. (2012), Contributions to ionospheric determination with Global Positioning System: solar flare detection and prediction of global maps of Total Electron Content, Ph.D. dissertation. Doctoral Program in Aerospace Science & Technology, Technical University of Catalonia, Barcelona, Spain]).
2016-04-22T12:01:23ZGarcía Rigo, AlbertoNuñez, MarlonQahwaji, RamiAshamari, Omar WJiggens, PiersPérez, GustauHernández Pajares, ManuelHilgers, AlainA web-based prototype system for predicting Solar Flares and Solar Energetic Particle (SEP) events for its use by space launcher operators or any interested user has been implemented. The main goal of this system, called SEPsFLAREs, is to provide warnings/predictions with forecast horizons from 48 hours before to a few hours before to the SEP peak flux, and duration predictions. The module responsible for predicting solar flares, the SF_PMod, is based on the well-known ASAP flare predictor [T. Colak & R. Qahwaji, Automated solar activity prediction: A hybrid computer platform using machine learning and solar imaging for automated prediction of solar flares, Space Weather, 7 (S06001), 2009], which learns rules by using machine learning techniques on SDO/SOHO solar images to automatically detect sunspots, classify them based on the McIntosh classification system, and predict C-, M-, and X-class flares with forecast horizon from 6 h to 48 h. Regarding the performance of the flare predictor, the 24-hour forecast horizon was found to provide the best performance: the Probability of Detection (POD), False Alarm Ratio (FAR) and True Skill Statistics estimations were 63.8%, 99.0% and 0.5 respectively for predicting X-class flares; and 88.7%, 87.0% and 0.59 respectively, for predicting M-class flares. The module responsible for predicting the SEP onset and occurrence, the SEP_OO_PMod, is based on the well-known UMASEP predictor [M. Núñez, Predicting solar energetic proton events (E > 10 MeV), Space Weather, 9 (S07003), 2011], which performs X-ray and proton flux correlations to find the first symptoms of future well- and poorly-connected SEP events. The SEP_OO_PMod also provides a Warning Tool which is able to warn about potential proton enhancements (including SEP events) from flare predictions. Regarding the performance of the SEP_OO_PMod, it was validated taking into account all 129 SEP events from January 1994 to June 2014 and obtained a POD of 86.82%, a FAR of 25.83%, and an Average Warning Time (AWT) of 3.93 h. Regarding the evaluation of the Warning Tool, the best performance, obtained with a set of user-defined parameters, were a POD of 58.3%, FAR of 90.1%, and AWT of 23.1 h. The module responsible for predicting SEP peak and duration, the SEP_FID_PMod, identifies the parent solar flare associated to an observed/predicted SEP, simulates the radial propagation of the predicted shock on a representative IMF structure (i.e. a static Parker Spiral), and predicts the SEP peak and duration. The SEP_FID_PMod, validated taking into account all 129 SEP events from January 1994 to June 2014, obtained a Mean Absolute Error (MAE) of SEP peak time predictions of 11.3 h, a MAE of peak intensity predictions of 0.53 in log10 units of pfu, and a MAE of SEP end time predictions of 28.8 h. The SEPsFLAREs system also acquires data for solar flares nowcasting (including GSFLAD proxy and SISTED detector from MONITOR’s ESA-funded project; [Hernández-Pajares, M., A. García-Rigo, J.M. Juan, J. Sanz, E. Monte and A. Aragón-Ángel (2012), GNSS measurement of EUV photons flux rate during strong and mid solar flares. Space Weather, Volume 10, Issue 12, doi:10.1029/2012SW000826] and [García-Rigo, A. (2012), Contributions to ionospheric determination with Global Positioning System: solar flare detection and prediction of global maps of Total Electron Content, Ph.D. dissertation. Doctoral Program in Aerospace Science & Technology, Technical University of Catalonia, Barcelona, Spain]).Sensorless force estimation using a neuro-vision-based approach for robotic-assisted surgery
http://hdl.handle.net/2117/86088
Sensorless force estimation using a neuro-vision-based approach for robotic-assisted surgery
Avilés Rivero, Angélica Ivone; Alsaleh, Samar M.; Sobrevilla Frisón, Pilar; Casals Gelpi, Alicia
This paper addresses the issue of lack of force feedback in robotic-assisted minimally invasive surgeries. Force is an important measure for surgeons in order to prevent intra-operative complications and tissue damage. Thus, an innovative neuro-vision based force estimation approach is proposed. Tissue surface displacement is first measured via minimization of an energy functional. A neuro approach is then used to establish a geometric-visual relation and estimate the applied force. The proposed approach eliminates the need of add-on sensors, carrying out biocompatibility studies and is
applicable to tissues of any shape. Moreover, we provided an improvement from 15.14% to 56.16% over other approaches which demonstrate the potential of our proposal
2016-04-22T07:55:43ZAvilés Rivero, Angélica IvoneAlsaleh, Samar M.Sobrevilla Frisón, PilarCasals Gelpi, AliciaThis paper addresses the issue of lack of force feedback in robotic-assisted minimally invasive surgeries. Force is an important measure for surgeons in order to prevent intra-operative complications and tissue damage. Thus, an innovative neuro-vision based force estimation approach is proposed. Tissue surface displacement is first measured via minimization of an energy functional. A neuro approach is then used to establish a geometric-visual relation and estimate the applied force. The proposed approach eliminates the need of add-on sensors, carrying out biocompatibility studies and is
applicable to tissues of any shape. Moreover, we provided an improvement from 15.14% to 56.16% over other approaches which demonstrate the potential of our proposalCounting configuration–free sets in groups
http://hdl.handle.net/2117/86058
Counting configuration–free sets in groups
Rué Perna, Juan José; Serra Albó, Oriol; Vena Cros, Lluís
We present a unified framework to asymptotically count the number of sets, with a given cardinality, free of certain configurations. This is done by combining the hypergraph containers methodology joint with arithmetic removal lemmas. Several applications involving linear configurations are described, as well as some applications in the random sparse setting.
2016-04-21T11:49:48ZRué Perna, Juan JoséSerra Albó, OriolVena Cros, LluísWe present a unified framework to asymptotically count the number of sets, with a given cardinality, free of certain configurations. This is done by combining the hypergraph containers methodology joint with arithmetic removal lemmas. Several applications involving linear configurations are described, as well as some applications in the random sparse setting.Lissajous curves: an experiment in creative coding
http://hdl.handle.net/2117/85586
Lissajous curves: an experiment in creative coding
Barrière Figueroa, Eulalia
Do you want to become a creative coder for a day? When artists use a computer to make art, they often experience the need of improving their mathematical skills. On the other hand, students with technical skills are less comfortable with aesthetic issues and creative work. In this workshop we use Processing to build two animations that involve: (1) the use of trigonometry and polar coordinates in parametric curves, and (2) the (soft) implementation of Hooke’s law. Our goal is to show that creative coding is a rewarding way of learning mathematics, with a creative approach.
2016-04-13T09:45:14ZBarrière Figueroa, EulaliaDo you want to become a creative coder for a day? When artists use a computer to make art, they often experience the need of improving their mathematical skills. On the other hand, students with technical skills are less comfortable with aesthetic issues and creative work. In this workshop we use Processing to build two animations that involve: (1) the use of trigonometry and polar coordinates in parametric curves, and (2) the (soft) implementation of Hooke’s law. Our goal is to show that creative coding is a rewarding way of learning mathematics, with a creative approach.Proyecto, desarrollo y valoración en la UPC de un caso de feedforwarding en campus virtual
http://hdl.handle.net/2117/85557
Proyecto, desarrollo y valoración en la UPC de un caso de feedforwarding en campus virtual
Fabregat Fillet, Jaume; Pelayo Melero, Ignacio Manuel; Valero Baya, Jordi; Ornat Longarón, Cèsar; Achaerandio Puente, María Isabel; Pineda Soler, Eloi; Buenestado Caballero, Pablo
Docentes de UPC, UB, UAB, UIB, UOC y URV investigamos sobre una evaluación formativa "feedforwarding", que realimente de inmediato, que no se limite al "correcto-incorrecto", que guíe más que resuelva, que sea suficientemente individualizada, que motive reflexión - acción y que genere un trabajo sostenible para alumnos y profesores.
La aplicación en la UPC ha recaído sobre "Matemáticas" del primer cuatrimestre en la Escuela Superior de Agricultura de Barcelona. Se ha diseñado una experiencia transferible a más asignaturas, que usa apoyos de NTIC y que permite analizar eventuales logros resultantes de su despliegue. Para fomentar el aprendizaje se han administrado cuestionarios sobre la disciplina, con y sin realimentación. Los estudiantes han considerado primero un cuestionario con realimentación reiterada hasta que responden bien todas las preguntas y, posteriormente, han afrontado un cuestionario similar sin realimentación.
Se ha actuado sobre unos doscientos estudiantes, con cinco cuestionarios dobles generados con WIRIS (correspondientes a los cinco temas de la asignatura), empleando la versión Moodle 2.6.2. Se ha estudiado la contribución al rendimiento académico y la satisfacción de los agentes, constatándose aumento de dedicación a la materia, mejoras (no duraderas) en el aprendizaje y valoración positiva del paso dado.
2016-04-12T11:42:44ZFabregat Fillet, JaumePelayo Melero, Ignacio ManuelValero Baya, JordiOrnat Longarón, CèsarAchaerandio Puente, María IsabelPineda Soler, EloiBuenestado Caballero, PabloDocentes de UPC, UB, UAB, UIB, UOC y URV investigamos sobre una evaluación formativa "feedforwarding", que realimente de inmediato, que no se limite al "correcto-incorrecto", que guíe más que resuelva, que sea suficientemente individualizada, que motive reflexión - acción y que genere un trabajo sostenible para alumnos y profesores.
La aplicación en la UPC ha recaído sobre "Matemáticas" del primer cuatrimestre en la Escuela Superior de Agricultura de Barcelona. Se ha diseñado una experiencia transferible a más asignaturas, que usa apoyos de NTIC y que permite analizar eventuales logros resultantes de su despliegue. Para fomentar el aprendizaje se han administrado cuestionarios sobre la disciplina, con y sin realimentación. Los estudiantes han considerado primero un cuestionario con realimentación reiterada hasta que responden bien todas las preguntas y, posteriormente, han afrontado un cuestionario similar sin realimentación.
Se ha actuado sobre unos doscientos estudiantes, con cinco cuestionarios dobles generados con WIRIS (correspondientes a los cinco temas de la asignatura), empleando la versión Moodle 2.6.2. Se ha estudiado la contribución al rendimiento académico y la satisfacción de los agentes, constatándose aumento de dedicación a la materia, mejoras (no duraderas) en el aprendizaje y valoración positiva del paso dado.Ramsey numbers for empty convex polygons
http://hdl.handle.net/2117/85553
Ramsey numbers for empty convex polygons
Bautista-Santiago, Crevel; Cano, Javier; Fabila-Monroy, Ruy; Hidalgo-Toscano, Carlos; Huemer, Clemens; Leaños, Jesús; Sakai, Toshinori; Urrutia, Jorge
We study a geometric Ramsey type problem where the vertices of the complete graph Kn are placed on a set S of n points in general position in the plane, and edges are drawn as straight-line segments. We define the empty convex polygon Ramsey number REC (k, k) as the smallest number n such that for every set S of n points and for every two-coloring of the edges of Kn drawn on S, at least one color class contains an empty convex k-gon. A polygon is empty if it contains no points from S in its interior. We prove 17 ≤ REC (3, 3) ≤ 463 and 57 ≤ REC (4, 4). Further, there are three-colorings of the edges of Kn (drawn on a set S) without empty monochromatic triangles. A related Ramsey number for islands in point sets is also studied.
2016-04-12T11:19:04ZBautista-Santiago, CrevelCano, JavierFabila-Monroy, RuyHidalgo-Toscano, CarlosHuemer, ClemensLeaños, JesúsSakai, ToshinoriUrrutia, JorgeWe study a geometric Ramsey type problem where the vertices of the complete graph Kn are placed on a set S of n points in general position in the plane, and edges are drawn as straight-line segments. We define the empty convex polygon Ramsey number REC (k, k) as the smallest number n such that for every set S of n points and for every two-coloring of the edges of Kn drawn on S, at least one color class contains an empty convex k-gon. A polygon is empty if it contains no points from S in its interior. We prove 17 ≤ REC (3, 3) ≤ 463 and 57 ≤ REC (4, 4). Further, there are three-colorings of the edges of Kn (drawn on a set S) without empty monochromatic triangles. A related Ramsey number for islands in point sets is also studied.On the disks with diameters the sides of a convex 5-gon
http://hdl.handle.net/2117/85548
On the disks with diameters the sides of a convex 5-gon
Huemer, Clemens; Pérez-Lantero, Pablo
We prove that for any convex pentagon there are two disks, among the five disks having a side of the pentagon as diameter and the midpoint of the side as its center, that do not intersect. This shows that K5 is never the intersection graph of such five disks.
2016-04-12T10:55:15ZHuemer, ClemensPérez-Lantero, PabloWe prove that for any convex pentagon there are two disks, among the five disks having a side of the pentagon as diameter and the midpoint of the side as its center, that do not intersect. This shows that K5 is never the intersection graph of such five disks.Structural health monitoring by means of strain field pattern recognition on the basis of PCA and automatic clustering techniques based on SOM
http://hdl.handle.net/2117/85487
Structural health monitoring by means of strain field pattern recognition on the basis of PCA and automatic clustering techniques based on SOM
Sierra-Pérez, Julian; Torres-Arredondo, Miguel Ángel; Cabanes, Guénaël; Güemes Gordo, Alfredo; Mujica Delgado, Luis Eduardo
2016-04-11T12:54:26ZSierra-Pérez, JulianTorres-Arredondo, Miguel ÁngelCabanes, GuénaëlGüemes Gordo, AlfredoMujica Delgado, Luis EduardoRevisión de control adaptativo por modelo de referencia con síntesis de controlador mínima y aplicación al control de velocidad de un motor DC
http://hdl.handle.net/2117/85453
Revisión de control adaptativo por modelo de referencia con síntesis de controlador mínima y aplicación al control de velocidad de un motor DC
Larco Barros, Ciro M.; Costa Castelló, Ramon; Olm Miras, Josep Maria
En este artículo se revisan los aspectos basicos del Control Adaptativo por Modelo de Referencia con Síntesis de Controlador Mínima, tanto en su version de tiempo continuo como en la de tiempo discreto. A su vez, se ilustran sus principales características de funcionamiento a partir del control de velocidad de un motor DC con parametros inciertos sometido a perturbaciones periódicas, para el cual se aportan resultados numericos y experimentales
2016-04-11T07:58:09ZLarco Barros, Ciro M.Costa Castelló, RamonOlm Miras, Josep MariaEn este artículo se revisan los aspectos basicos del Control Adaptativo por Modelo de Referencia con Síntesis de Controlador Mínima, tanto en su version de tiempo continuo como en la de tiempo discreto. A su vez, se ilustran sus principales características de funcionamiento a partir del control de velocidad de un motor DC con parametros inciertos sometido a perturbaciones periódicas, para el cual se aportan resultados numericos y experimentalesForce-feedback sensory substitution using supervised recurrent learning for robotic-assisted surgery
http://hdl.handle.net/2117/85399
Force-feedback sensory substitution using supervised recurrent learning for robotic-assisted surgery
Avilés Rivero, Angélica; Alsaleh, Samar M.; Sobrevilla Frisón, Pilar; Casals Gelpi, Alicia
The lack of force feedback is considered one of the major limitations in Robot Assisted Minimally Invasive Surgeries. Since add-on sensors are not a practical solution for clinical environments, in this paper we present a force estimation approach that starts with the reconstruction of a 3D deformation structure of the tissue surface by minimizing an energy functional. A Recurrent Neural Network-Long Short Term Memory (RNN-LSTM) based architecture is then presented
to accurately estimate the applied forces. According to the results, our solution offers long-term stability and shows a significant percentage of accuracy improvement, ranging from about 54% to 78%, over existing approaches.
2016-04-08T09:40:02ZAvilés Rivero, AngélicaAlsaleh, Samar M.Sobrevilla Frisón, PilarCasals Gelpi, AliciaThe lack of force feedback is considered one of the major limitations in Robot Assisted Minimally Invasive Surgeries. Since add-on sensors are not a practical solution for clinical environments, in this paper we present a force estimation approach that starts with the reconstruction of a 3D deformation structure of the tissue surface by minimizing an energy functional. A Recurrent Neural Network-Long Short Term Memory (RNN-LSTM) based architecture is then presented
to accurately estimate the applied forces. According to the results, our solution offers long-term stability and shows a significant percentage of accuracy improvement, ranging from about 54% to 78%, over existing approaches.