A weakly-supervised approach for discovering common objects in airport video surveillance footage

Object detection in video is a relevant task in computer vision. Standard and current detectors are typically trained in a strongly supervised way, what requires a huge amount of labelled data. In contrast, in this paper we focus on object discovery in video sequences by using sets of unlabelled data. Thus, we present an approach based on the use of two region proposal algorithms (a pretrained Region Proposal Network and an Optical Flow Proposal) to produce regions of interest that will be grouped using a clustering algorithm. Therefore, our system does not require the collaboration of a human except for assigning human understandable labels to the discovered clusters. We evaluate our approach in a set of videos recorded at the outdoor area of an airport where the aeroplanes park to load passengers and luggage (apron area). Our experimental results suggest that the use of an unsupervised approach is valid for automatic object discovery in video sequences, obtaining a CorLoc of 86.8 and a mAP of 0.374 compared to a CorLoc of 70.4 and mAP of 0.683 achieved by a supervised Faster R-CNN trained and tested on the same dataset.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Estudio comparativo de diferentes técnicas de implantación de stents en bifurcaciones coronarias

ResumenEl objetivo de este trabajo es el análisis comparativo de los cambios hemodinámicos locales producidos en una bifurcación coronaria por el implante de stents mediante 3 técnicas diferentes: stent simple en la arteria principal, stent simple en la arteria principal con orificio de comunicación con la arteria secundaria para el paso de un balón de inflado («kissing») y «culotte». Para ello se ha utilizado la geometría ideal de una bifurcación coronaria a 45 y 90°.En primer lugar se simularon los modelos en régimen estacionario mediante el código comercial ANSYS Fluent, y a continuación se validaron con las medidas experimentales tomadas en el laboratorio mediante velocimetría de imagen de partículas (particle image velocimetry [PIV]). Una vez obtenida una buena concordancia de resultados entre ambos estudios en régimen permanente, se abordó el flujo pulsátil. Los parámetros que se consideraron para comparar las diferentes técnicas en este régimen fueron los esfuerzos cortantes y la caída de presión promediados en el tiempo, así como el índice de esfuerzos cortantes oscilatorios (oscillatory shear index [OSI]). Las conclusiones finales fueron que el stent simple presenta los peores resultados, en términos de caída de presión, y la técnica «kissing», los mejores. Esto sería aplicable a los stents liberadores de fármacos, donde la reestenosis no es tan crucial como el restablecimiento del flujo sanguíneo. En cuanto al criterio basado en el valor menor de los esfuerzos cortantes (<0,4Pa) y un OSI elevado (>0,1), la técnica «culotte» presenta el peor comportamiento. Esto sería aplicable a los stents sin recubrimiento, en que la mejor opción sería el stent simple.AbstractThe objective of this work is to analyze the local hemodynamic changes caused in a coronary bifurcation by three different stenting techniques: simple stenting of the main vessel, simple stenting of the main vessel with kissing balloon in the side branch and culotte. To carry out this study an idealized geometry of a coronary bifurcation is used, and two bifurcation angles, 45° and 90°, are chosen as representative of the wide variety of real configurations. Both numerical simulations and experimental measurements are performed. First, steady simulations are carried out with the commercial code ANSYS Fluent, then, experimental measurements with PIV (Particle Image Velocimetry), obtained in the laboratory, are used to validate the numerical simulations. The steady computational simulations show a good overall agreement with the experimental data. Second, pulsatile flow is considered to take into account the transient effects. The time averaged wall shear stress, oscillatory shear index (OSI) and pressure drop obtained numerically are used to compare the behavior of the stenting techniques. As conclusions obtained, simple stenting technique shows the worst results in terms of pressure drop, and kissing the best ones. This criterion could be applied for DES (Drug Eluting Stents) where the restenosis is not as critical as the reestablishment of the blood flow. But considering the regions of low wall shear stress (<0.4Pa) and elevated OSI (>0.1), the culotte procedure shows the worst performance and the simple stent, the best. This could be applied to BMS (Bare Metal Stents)

Stellar activity in barium stars .1. Analysis of H-lines and K-lines CA-II-lines in 10 barium stars

High dispersion spectra have been obtained in order to study the activity level of ten barium stars by means of the Ca II H and K emission flux, looking for a relation between barium intensity index and activity. Absolute magnitudes obtained from the Wilson-Bappu relationship disagree, in some cases, with the magnitudes computed from parallaxes, but this fact is not due to barium nature. Total emission fluxes, F(H + K) or R_HK index, plotted versus effective temperature show a distribution similar to that of cool giant stars. The asymmetry of K emission line, [F(K_2ν)/F(K_2r)], has been analyzed in relation with effective temperature, in this sense barium stars behave as expected of late-type giants with the only exception of two stars

Exploiting graphic processing units parallelism to improve intelligent data acquisition system performance in JET's correlation reflectometer

The performance of intelligent data acquisition systems relies heavily on their processing capabilities and local bus bandwidth, especially in applications with high sample rates or high number of channels. This is the case of the self adaptive sampling rate data acquisition system installed as a pilot experiment in KG8B correlation reflectometer at JET. The system, which is based on the ITMS platform, continuously adapts the sample rate during the acquisition depending on the signal bandwidth. In order to do so it must transfer acquired data to a memory buffer in the host processor and run heavy computational algorithms for each data block. The processing capabilities of the host CPU and the bandwidth of the PXI bus limit the maximum sample rate that can be achieved, therefore limiting the maximum bandwidth of the phenomena that can be studied. Graphic processing units (GPU) are becoming an alternative for speeding up compute intensive kernels of scientific, imaging and simulation applications. However, integrating this technology into data acquisition systems is not a straight forward step, not to mention exploiting their parallelism efficiently. This paper discusses the use of GPUs with new high speed data bus interfaces to improve the performance of the self adaptive sampling rate data acquisition system installed on JET. Integration issues are discussed and performance evaluations are presente

Photovoltaic solar energy. A pedagogic approach

The present work reports on a simple pedagogic exploration of a photovoltaic solar kit which aims to demonstrate the operation of a mobile orientable photovoltaic solar energy collection system employing a robot built with Lego parts