206 research outputs found

    Rostros humanos, de frente, en la cerámica ibérica

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    Automated Deployment of a Spark Cluster with Machine Learning Algorithm Integration

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    The vast amount of data stored nowadays has turned big data analytics into a very trendy research field. The Spark distributed computing platform has emerged as a dominant and widely used paradigm for cluster deployment and big data analytics. However, to get started up is still a task that may take much time when manually done, due to the requisites that all nodes must fulfill. This work introduces LadonSpark, an open-source and non-commercial solution to configure and deploy a Spark cluster automatically. It has been specially designed for easy and efficient management of a Spark cluster with a friendly graphical user interface to automate the deployment of a cluster and to start up the distributed file system of Hadoop quickly. Moreover, LadonSpark includes the functionality of integrating any algorithm into the system. That is, the user only needs to provide the executable file and the number of required inputs for proper parametrization. Source codes developed in Scala, R, Python, or Java can be supported on LadonSpark. Besides, clustering, regression, classification, and association rules algorithms are already integrated so that users can test its usability from its initial installation.Ministerio de Ciencia, Innovación y Universidades TIN2017-88209-C2-1-

    A Comparative Study of Fracture Toughness at Cryogenic Temperature of Austenitic Stainless Steel Welds

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    The ITER magnet system is based on the "cable-in-conduit" conductor (CICC) concept, which consists of stainless steel jackets filled with superconducting strands. The jackets provide high strength, limited fatigue crack growth rate and fracture toughness properties to counteract the high stress imposed by, among others, electromagnetic loads at cryogenic temperature. Austenitic nitrogen-strengthened stainless steels have been chosen as base material for the jackets of the central solenoid and the toroidal field system, for which an extensive set of cryogenic mechanical property data are readily available. However, little is published for their welded joints, and their specific performance when considering different combinations of parent and filler metals. Moreover, the impact of post-weld heat treatments that are required for Nb3Sn formation is not extensively treated. Welds are frequently responsible for cracks initiated and propagated by fatigue during service, causing structural failure. It becomes thus essential to select the most suitable combination of parent and filler material and to assess their performance in terms of strength and crack propagation at operation conditions. An extensive test campaign has been conducted at 7 K comparing tungsten inert gas (TIG) welds using two fillers adapted to cryogenic service, EN 1.4453 and JK2LB, applied to two different base metals, AISI 316L and 316LN.The authors would like to express their thanks to Dr. Arman Nyilas (in memorian) for the contributions made in this work

    Non-Invasive Electrophysiological Mapping Entropy Predicts Atrial Fibrillation Ablation Efficacy Better Than Clinical Characteristics

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    [EN] Success rate of atrial fibrillation (AF) ablation remains far from satisfactory. In this study, a 6 months AF freedom predictive model based on Fuzzy Entropy of non-invasive body surface potential maps is compared with clinical predictors. The study included 29 patients referred for pulmonary vein isolated catheter ablation procedure. Non-invasive electrocardiographic mapping with 54 ECG electrodes was recorded for all patients during the ablation procedure. Six months follow up was used to evaluate the efficacy of the ablation procedure. Predictions based on non-invasive electrocardiographic mappings during adenosine infusion (accuracy: 90%, AUC: 0.93) showed a clear improvement over standard-of-care clinical parameter models (accuracy: 62.1%, AUC: 0. 54). Our results indicate that measurements of electrophysiological complexity of AF signals could improve the clinical practice by predicting the efficacy of AF ablation procedures.This work was supported by the Instituto de Salud Carlos III FEDER (DTS16/00160; PI16/01123; PI17/01059; PI17/01106; EIT-Health 19600 AFFINE)De La Nava, AS.; Fabregat, MC.; Rodrigo, M.; Hernández, I.; Liberos, A.; Fernández-Avilés, F.; Guillem Sánchez, MS.... (2019). Non-Invasive Electrophysiological Mapping Entropy Predicts Atrial Fibrillation Ablation Efficacy Better Than Clinical Characteristics. IEEE. 1-4. https://doi.org/10.22489/CinC.2019.299S1

    Sintering by SPS of ultrafine TiCx N1-x powders obtained using mechanically induced self sustaining reaction

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    [EN] In this work high purity and nanometer character titanium carbonitride TiCx N1-x powders were obtained by mechanically induced self sustaining reaction (MSR) in a high-energy planetary ball mill, from a mixture of titanium with graphite or carbon nanofiber (CNFs) in a nitrogen atmosphere. A promising method for developing these materials is the coupling of the MSR with SPS sintering technique. The product is sintered at 1400 ºC and 1700 ºC, obtaining a completely dense monolithic ceramic (>99% t.d). In this work, the influence of SPS treatment and carbon precursor on material microstructures was studied and the main mechanical properties of the end material were evaluated[ES] En el presente trabajo se han obtenido carbonitruros de titanio TiCx N1-x de alta pureza y con carácter nanométrico, por molienda reactiva (MSR) de alta energía en un molino planetario, a partir de la mezcla de titanio con grafito o nanofibras de carbono (CNFs) en una atmósfera de nitrógeno. Una metodología prometedora para el desarrollo de estos materiales consiste en el acoplamiento de la técnica MSR con el sinterizado por SPS. El producto obtenido se ha sinterizado a 1400 ºC y 1700 ºC, obteniéndose una cerámica monolítica totalmente densa (>99% d.t). En este trabajo se analizan las distintas microestructuras obtenidas en función del precursor de carbono y el tratamiento de SPS, evaluando las principales propiedades mecánicas de los materiales resultantes.Este trabajo ha sido llevado acabo con financiación procedente de los proyectos del plan nacional MAT2006-01783 y MAT2006-04911.Borrell Tomás, MA.; Fernández, A.; Torrecillas, R.; Córdoba, J.; Avilés, M.; Gotor, F. (2010). Sinterización por SPS de polvos ultrafinos de TiCxN1-x obtenidos mediante reacciones de autopropagación inducidas mecánicamente. Boletín de la Sociedad Española de Cerámica y Vidrio. 49(5):357-360. http://hdl.handle.net/10251/64404S35736049

    Solving Inaccuracies in Anatomical Models for Electrocardiographic Inverse Problem Resolution by Maximizing Reconstruction Quality

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    [EN] Electrocardiographic Imaging has become an increasingly used technique for non-invasive diagnosis of cardiac arrhythmias, although the need for medical imaging technology to determine the anatomy hinders its introduction in the clinical practice. This paper explores the ability of a new metric based on the inverse reconstruction quality for the location and orientation of the atrial surface inside the torso. Body surface electrical signals from 31 realistic mathematical models and four AF patients were used to estimate the optimal position of the atria inside the torso. The curvature of the L-curve from the Tikhonov method, which was found to be related to the inverse reconstruction quality, was measured after application of deviations in atrial position and orientation. Independent deviations in the atrial position were solved by finding the maximal L-curve curvature with an error of 1.7 +/- 2.4 mm in mathematical models and 9.1 +/- 11.5 mm in patients. For the case of independent angular deviations, the error in location by using the L-curve was 5.8 +/- 7.1 degrees in mathematical models and 12.4 degrees +/- 13.2 degrees in patients. The ability of the L-curve curvature was tested also under superimposed uncertainties in the three axis of translation and in the three axis of rotation, and the error in location was of 2.3 +/- 3.2 mm and 6.4 degrees +/- 7.1 degrees in mathematical models, and 7.9 +/- 10.7 mm and 12.1 degrees +/- 15.5 degrees in patients. The curvature of L-curve is a useful marker for the atrial position and would allow emending the inaccuracies in its location.This work was supported in part by Generalitat Valenciana under Grant ACIF/2013/021, in part by the Instituto de Salud Carlos III, Ministry of Economy and Competitiveness, Spain, under Grant PI13-01882, Grant PI13-00903, Grant PI14/00857, Grant TEC2013-46067-R, and Grant DTS16/00160, in part by the Spanish Society of Cardiology (Grant for Clinical Research in Cardiology 2015), and in part by the Spanish Ministry of Science and Innovation (Red RIC) under Grant PLE2009-0152.Rodrigo Bort, M.; Climent, AM.; Liberos Mascarell, A.; Hernández-Romero, I.; Arenal, A.; Bermejo, J.; Fernández-Avilés, F.... (2018). Solving Inaccuracies in Anatomical Models for Electrocardiographic Inverse Problem Resolution by Maximizing Reconstruction Quality. IEEE Transactions on Medical Imaging. 37(3):733-740. https://doi.org/10.1109/TMI.2017.2707413S73374037
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