Wind turbine condition monitoring strategy through multiway PCA and multivariate inference

This article states a condition monitoring strategy for wind turbines using a statistical data-driven modeling approach by means of supervisory control and data acquisition (SCADA) data. Initially, a baseline data-based model is obtained from the healthy wind turbine by means of multiway principal component analysis (MPCA). Then, when the wind turbine is monitorized, new data is acquired and projected into the baseline MPCA model space. The acquired SCADA data are treated as a random process given the random nature of the turbulent wind. The objective is to decide if the multivariate distribution that is obtained from the wind turbine to be analyzed (healthy or not) is related to the baseline one. To achieve this goal, a test for the equality of population means is performed. Finally, the results of the test can determine that the hypothesis is rejected (and the wind turbine is faulty) or that there is no evidence to suggest that the two means are different, so the wind turbine can be considered as healthy. The methodology is evaluated on a wind turbine fault detection benchmark that uses a 5 MW high-fidelity wind turbine model and a set of eight realistic fault scenarios. It is noteworthy that the results, for the presented methodology, show that for a wide range of significance, a in [1%, 13%], the percentage of correct decisions is kept at 100%; thus it is a promising tool for real-time wind turbine condition monitoring.Peer ReviewedPostprint (published version

Beilinson-Flach elements, Stark units and p-adic iterated integrals

We study weight one specializations of the Euler system of Beilinson–Flach elements introduced by Kings, Loeffler and Zerbes, with a view towards a conjecture of Darmon, Lauder and Rotger relating logarithms of units in suitable number fields to special values of the Hida–Rankin p-adic L-function. We show that the latter conjecture follows from expected properties of Beilinson–Flach elements and prove the analogue of the main theorem of Castella and Hsieh about generalized Kato classes.Peer ReviewedPostprint (author's final draft

Open problems in a recent algebraic method in phylogenetics

2014/201

Birch and Swinertonn-Dyer conjecture

Esta tesis tiene diversos objetivos: el primero de ellos es introducir temas básicos de teoría de números, empezando por la teoría algebraica (cuerpos de clases, teorema de Dirichlet...) y continuando por una exposición introductoria de curvas elípticas hasta llegar a probar Mordell-Weil (introduciendo para ello nociones básicas de geometría algebraica y cohomología). Se introducen también las series L, enfatizando su importancia, y se da realiza una presentación de las formas modulares: se expone la teoría analítica clásica, los operadores de Hecke, teoría de formas nuevas y viejas, autoformas... y luego se explica la relación que existe con las curvas elípticas, a través de resultados como los de Eichler y Shimura o más recientemente los de Wiles y otros. Finalmente, se llega a la conjetura de BSD, de la cual se enuncian (y a veces se dan ideas de la prueba) los resultados más importantes, tanto los clásicos de Coates-Wiles y Gross-Zagier como otros mucho más recientes de Darmon y Rotger

Stark's points and units

El objetivo de este trabajo es el estudio de un análogo de la conjetura elíptica de Stark para unidades en cuerpos de números. Para ello, utilizamos el sistema de Euler de elementos de Beilinson-Flach y la posibilidad de interpolar p-ádicamente sus imágenes a través de reguladores étale. Los resultados de Kings, Loeffler y Zerbes nos permiten relacionar las clases de cohomología así construidas con ciertos valores de una función L p-ádica de Hida-Rankin de tres variables, donde también tenemos el concepto de variación p-ádica. Del mismo modo que el sistema de Euler de los ciclos diagonales permite estudiar la conjetura elíptica de Stark, el de Beilinson-Flach nos permitirá ofrecer evidencia teórica a la conjetura de Stark para unidades que formulan Darmon, Lauder y Rotger, que quedaría probada si fuésemos capaces de establecer ciertas relaciones conjeturales que involucran también a periodos p-ádicos. En este trabajo, además, hay una parte en la que se recuerdan ciertos resultados teóricos que ofrecen soporte a los que nosotros derivamos, centrándonos en el estudio de funciones L p-ádicas, formas modulares p-ádicas y sobreconvergentes y familias de Hida

Populism by the people: An analysis of online comments in Portugal and Spain

There exists a gap in research on populism which tends to focus on politicians rather than on the people. This research addresses that by assessing the prevalence of populism and analyses citizens’ populist discourse in online comments in Portugal and Spain. The methodological approach is based on quantitative content analysis and co-occurrence textual analysis. The main findings point to a similar salience of anti-elitism in both countries, despite the differ- ent levels of electoral success of populist parties. These findings suggest that more attention should be paid to the views of citizens in populism research.Fundação para a Ciência e Tecnologiainfo:eu-repo/semantics/publishedVersio

Trends in condition monitoring of pitch bearings

The value of wind power generation for energy sustainability in the future is undeniable. Since operation and maintenance activities take a sizeable portion of the cost associated with offshore wind turbines operation, strategies are needed to decrease this cost. One strategy, condition monitoring (CM) of wind turbines, allows the extension of useful life for several parts, which has generated great interest in the industry. One critical part are the pitch bearings, by virtue of the time and logistics involved in their maintenance tasks. As the complex working conditions of pitch bearings entail the need for diverse and innovative monitoring techniques, the classical bearing analysis techniques are notsuitable. This paper provides a literature review of several condition monitoring techniques, organized as follows: first, arranged according to the nature of the signal such as vibration, acoustic emission and others; second, arranged by relevant authors in compliance with signal nature. While little research has been found, an outline is significant for further contributions to the literature.Postprint (published version

Automatic verification of timing constraints for safety critical space systems

DASIA 2015, DAta Systems In Aerospace, 19-21 May, 2015, Barcelona, SpainIn this paper is presented an automatic process of verification. We focus in the verification of scheduling analysis parameter. This proposal is part of process based on Model Driven Engineering to automate a Verification and Validation process of the software on board of satellites. This process is implemented in a software control unit of the energy particle detector which is payload of Solar Orbiter mission. From the design model is generated a scheduling analysis model and its verification model. The verification as defined as constraints in way of Finite Timed Automatas. When the system is deployed on target the verification evidence is extracted as instrumented points. The constraints are fed with the evidence, if any of the constraints is not satisfied for the on target evidence the scheduling analysis is not valid.Ministerio de Economía y Competitivida

Determination of Thermophysical Properties of the Protic Ionic Liquid EIM NO₃, Pure and Doped with Lithium Nitrate Salt

[Abstract] In this work, viscosity, density and electrical conductivity of the ionic liquid, Ethylimidazolium Nitrate pure and doped with lithium nitrate salt were determined in order to check the properties’ improvement of the ionic liquid with the salt addition to consider these mixtures as potential electrolytes. Viscosity decreases exponentially as temperature increases, and increases with salt content, as expected. Density values decrease linearly as temperature increases and also increases with salt content. From electrical studies, an increase of conductivity with temperature and a decrease with salt concentration were observed. No significant differences between pure and doped sample were observed on Walden plots.This work was supported by Spanish Ministry of Economy and Competitiveness and FEDER Program through the projects MAT2014-57943-C3-1-P, MAT2014-57943-C3-3-P, MAT2017-89239-C2-1-P, as well as by Xunta de Galicia through GRC ED431C 2020/10 project and the Galician Network of Ionic Liquids (ReGaLIs) ED431D 2017/06. P. Vallet and J. J. Parajó thank funding support of FPI Program from Spanish Ministry of Science, Education and Universities and I2C postdoctoral Program of Xunta de Galicia, respectivelyXunta de Galicia; ED431C 2020/10Xunta de Galicia; ED431D 2017/0

Análisis de las competencias digitales para profesionales del sector turístico. Caso museólogos y guías turísticos.

Las competencias digitales son importantes en la actualidad, por lo tanto, los profesionales que se desempeñan en el ámbito turístico también deben poseer el conocimiento, las habilidades y destrezas sobre el manejo de estas herramientas, para estar a la altura de las exigencias del mercado y así satisfacer las necesidades de los turistas y visitantes. En este contexto surge el siguiente proyecto de investigación enfocado en realizar un estudio acerca de las competencias digitales requeridas por los profesionales que desempeñan como guías turísticos y en museos, en el cantón Manta. En referencia a la metodología, se aplica un cuestionario de encuesta a los guías de los museos y agencias de viajes para evaluar sus competencias actuales. Entre los resultados se concluye que los profesionales turísticos necesitan habilidades en el manejo de software y/o aplicaciones para la creación de tours, diseño de guianza virtual, manejo de herramientas tecnológicas como office y correo electrónico. Asimismo, se solicita de conocimientos en la aplicación de la realidad aumentada y manejo de redes sociales. Al finalizar se elabora un marco de competencias digitales con el objetivo de reducir la brecha entre las competencias del perfil profesional y las del mercado. Se identifican cuatro categorías: Saber (Gestión de la información y habilidades de comunicación). Saber hacer: (Manejo del segundo idioma (inglés), realidad aumentada y BIG data, uso de software/ y o aplicaciones para tours virtuales, entre otras). Ser: (Creatividad, liderazgo y capacidad innovadora). Genéricas y transversales: (Capacidad de análisis y síntesis, toma de decisiones y compromiso ético).Digital skills are important today, therefore, professionals who work in the tourism field must also have the knowledge, skills and abilities to manage these tools, to be up to the demands of the market and thus satisfying the needs of tourists and visitors. In this context, the following research project arises focused on conducting a study about the digital skills required by professionals who work as tour guides and in museums, in the Manta canton. In reference to the methodology, a survey questionnaire is applied to the guides of the museums and travel agencies to evaluate their current skills. Among the results, it is concluded that tourism professionals need skills in the management of software and/or applications for the creation of tours, virtual guide design, management of technological tools such as office and email. Likewise, knowledge is requested in the application of augmented reality and management of social networks. At the end, a framework of digital skills is developed with the aim of reducing the gap between the skills of the professional profile and those of the market. Four categories are identified: Know (Information management and communication skills). Know how to do: (Management of the second language (English), augmented reality and BIG data, use of software / and or applications for virtual tours, among others). Being: (Creativity, leadership and innovative capacity). Generic and transversal: (Capacity for analysis and synthesis, decision making and ethical commitment)