A family of Lyapunov-based control schemes for maximum power point tracking in buck converters

summary:This paper presents a novel family of Lyapunov-based controllers for the maximum power point tracking problem in the buck converter case. The solar power generation system here considered is composed by a stand-alone photovoltaic panel connected to a DC/DC buck converter. Lyapunov function candidates depending on the output are considered to develop conditions which, in some cases, can be expressed as linear matrix inequalities; these conditions guarantee that the output goes asymptotically to zero, thus implying that the MPPT is achieved. Simulation and real-time results are presented, which validate the effectiveness of the proposals

Polyp Localization and Segmentation in Colonoscopy Images by Means of a Model of Appearance for Polyps

Advisor/s: F. Javier Sánchez, Fernando Vilariño. Date and location of PhD thesis defense: 17 December 2012, Autonomous University of Barcelona.Colorectal cancer is the fourth most common cause of cancer death worldwide and its survival rate depends on the stage in which it is detected on hence the necessity for an early colon screening. There are several screening techniques but colonoscopy is still nowadays the gold standard, although it has some drawbacks such as the miss rate. Our contribution, in the field of intelligent systems for colonoscopy, aims at providing a polyp localization and a polyp segmentation system based on a model of appearance for polyps. To develop both methods we define a model of appearance for polyps, which describes a polyp as enclosed by intensity valleys. The novelty of our contribution resides on the fact that we include in our model aspects of the image formation and we also consider the presence of other elements from the endoluminal scene such as specular highlights and blood vessels, which have an impact on the performance of our methods. In order to develop our polyp localization method we accumulate valley information in order to generate energy maps, which are also used to guide the polyp segmentation. Our methods achieve promising results in polyp localization and segmentation. As we want to explore the usability of our methods we present a comparative analysis between physicians fixations obtained via an eye tracking device and our polyp localization method. The results show that our method is indistinguishable to novice physicians although it is far from expert physicians

Effects of globalization in small and medium enterprises (smes)

Las pequeñas y medianas empresas representan uno de los sectores económicos que captan el gran interés por los países del mundo, todos los proyectos, los organismos internacionales y regionales, y los investigadores en función de la evolución y los cambios de la economía mundial, debido al papel central en la producción, el empleo y la generación de ingresos, la innovación y el progreso tecnológico, así como su desempeño en la consecución de los objetivos económicos y sociales para todas las naciones. Pero hay que señalar que la situación actual del desarrollo económico en los países en desarrollo, tasas de empeoramiento y bajo crecimiento, son factores de los cuales se aprovechan los países desarrollados para alcanzar un alto nivel de desarrollo económico a través de las políticas de expansión empresarial. Ahora bien, las tendencias del nivel económico moderno nos llevaron a arrojar luz sobre las pequeñas y medianas empresas en los países en desarrollo, con todos los obstáculos que enfrenta este tipo de instituciones, con énfasis en el rol que en últimas juegan las organizaciones no gubernamentales en la financiación de la actividad económica. Desde esta perspectiva, se nota que la globalización va más allá del suelo territorial y administrativo de los países o las naciones, va más allá del estado físico o fronteras de la nación; “la palabra globalización vienen a la mente cada vez que hablamos de desarrollo masivo de las comunicaciones y la información, el espacio de internet y la tecnología” (La Desaparición de la Soberanía, la Publicación y Distribución, Amman 1994 p. 38).Small and medium enterprises represent one of the economic sectors that capture the great interest in the world, all projects, international and regional organizations, and researchers in light of developments and changes in the global economy due to its central role in production, employment and income generation, innovation and technological progress and its role in achieving economic and social goals for all nations. But it should be noted that the current situation of economic development in developing countries, worsening rates and low growth are the factors which developed countries are harnessed to achieve a high level of economic development through business expansion policies. However, the level of modern economic trends led us to shed light on small and medium enterprises in developing countries, with all the obstacles facing such institutions, with emphasis on the role that ultimately played by non-governmental organizations in the financing of economic activity. From this perspective, we note that globalization goes beyond the territorial and administrative floor of the countries or nations, it goes beyond the physical borders of the state or nation; "The word globalization come to mind whenever we talk of massive development of communication and information, the Internet space and technology" (La Desaparición de la Soberanía, la Publicación y Distribución, Amman 1994 p. 38)

Product placement: a theoretical-practical review of its capabilities and limitations

El product placement (la técnica publicitaria consistente en emplazar marcas dentro de películas, teleseries y otros medios) ha crecido enormemente en las últimas décadas y cuenta con unas expectativas de crecimiento muy halagüeñas para el futuro. Este artículo revisa el modelo de persuasión narrativa, que es un marco conceptual muy adecuado para entender por qué el cine y la televisión son capaces de modificar las creencias, intenciones y conductas del público y, más en particular, por qué el product placement es capaz de hacer que el público recuerde las marcas emplazadas, cambie de actitud hacia ellas e incluso acabe consumiéndolas. Este artículo también revisa cómo las productoras de cine/televisión, las agencias de publicidad/medios y los anunciantes se organizan en la práctica para gestionar que las marcas sean emplazadas en películas y teleseries. Además se analizan las ventajas, inconvenientes, oportunidades y amenazas que el product placement tiene en la actualidad, especialmente cuando se compara con la publicidad convencional. Una evaluación global de toda esta información permite concluir que el product placement es una técnica con mejores expectativas que la publicidad convencional para aquellas empresas que no disponen de los recursos de las grandes multinacionales pero que sí aspiran a penetrar efectivamente en los mercados internacionales

Use of Software Tools for Real-time Monitoring of Learning Processes: Application to Compilers subject

[EN] The effective implementation of the Higher European Education Area has meant a change regarding the focus of the learning process, being now the student at its very center. This shift of focus requires a strong involvement and fluent communication between teachers and students to succeed. Considering the difficulties associated to motivate students to take a more active role in the learning process, we explore how the use of a software tool can help both actors to improve the learning experience. We present a tool that can help students to obtain instantaneous feedback with respect to their progress in the subject as well as providing teachers with useful information about the evolution of knowledge acquisition with respect to each of the subject areas. We compare the performance achieved by students in two academic years: results show an improvement in overall performance which, after observing graphs provided by our tool, can be associated to an increase in students interest in the subject.This work has been supported by two teaching innovation projects awarded by Oficina de Qualitat Docent de la Universitat Autònoma de Barcelona (“Empleo de herramientas informáticas para monitorizar el proceso de aprendizaje en la asignatura Compiladors “ and “Análisis en tiempo real de resultados de aprendizaje obtenidos mediante herramientas de autoevaluación: Aplicación en la asignatura Compiladors”.http://ocs.editorial.upv.es/index.php/HEAD/HEAD18Sánchez, FJ.; Bernal, J. (2018). Use of Software Tools for Real-time Monitoring of Learning Processes: Application to Compilers subject. Editorial Universitat Politècnica de València. 1359-1366. https://doi.org/10.4995/HEAD18.2018.8205OCS1359136

Analysis and preconditioning of a probabilistic domain decomposition algorithm for elliptic boundary value problems

PDDSparse is a new hybrid parallelisation scheme for solving large-scale elliptic boundary value problems on supercomputers, which can be described as a Feynman-Kac formula for domain decomposition. At its core lies a stochastic linear, sparse system for the solutions on the interfaces, whose entries are generated via Monte Carlo simulations. Assuming small statistical errors, we show that the random system matrix ${\tilde G}(\omega)$ is near a nonsingular M-matrix $G$, i.e. ${\tilde G}(\omega)+E=G$ where $||E||/||G||$ is small. Using nonstandard arguments, we bound $||G^{-1}||$ and the condition number of $G$, showing that both of them grow moderately with the degrees of freedom of the discretisation. Moreover, the truncated Neumann series of $G^{-1}$ -- which is straightforward to calculate -- is the basis for an excellent preconditioner for ${\tilde G}(\omega)$. These findings are supported by numerical evidence

Spectral kissing and its dynamical consequences in the squeeze-driven Kerr oscillator

Transmon qubits are the predominant element in circuit-based quantum information processing, such as existing quantum computers, due to their controllability and ease of engineering implementation. But more than qubits, transmons are multilevel nonlinear oscillators that can be used to investigate fundamental physics questions. Here, they are explored as simulators of excited state quantum phase transitions (ESQPTs), which are generalizations of quantum phase transitions to excited states. We show that the spectral kissing (coalescence of pairs of energy levels) experimentally observed in the effective Hamiltonian of a driven SNAIL-transmon is an ESQPT precursor. We explore the dynamical consequences of the ESQPT, which include the exponential growth of out-of-time-ordered correlators, followed by periodic revivals, and the slow evolution of the survival probability due to localization. These signatures of ESQPT are within reach for current superconducting circuits platforms and are of interest to experiments with cold atoms and ion traps.NSF CCI grant (Award Number 2124511)NSF grant No. DMR-1936006I+D+i project PID2019-104002GB-C21 (MCIN/AEI/10.13039/501100-011033)The Consejería de Conocimiento, Investigación y Universidad, Junta de AndalucíaEuropean Regional Development Fund (ERDF), ref. UHU-1262561The CEAFMC and Universidad de Huelva High Performance Computer (HPC@UHU)The Campus Universitario el Carmen and funded by FEDER/MINECO project UNHU-15CE-2848The MPS Simons Foundation Award ID: 67858

Gamificación y valores: una propuesta transversal motivadora en Educación Física.

Tras observar la popularidad de los valores y su aparición, generalmente conflictiva, en diferentes medios de comunicación, pasando por un recorrido legislativo, donde se establece el desarrollo de valores personales y sociales como piedra angular del equilibrio en una sociedad desarrollada, surgen una serie de incógnitas relacionadas con los resultados obtenidos en materia de valores, del alumnado, siendo la medición de estos una asignatura pendiente. Existe un gran recorrido en la investigación y propuestas metodológicas en el trabajo de actitudes y valores en las aulas, no obstante, el principal reto sigue siendo que el alumnado sea capaz de interiorizar los valores, de hacerlos suyos, y no solo aprender su significado. Desde una experiencia en docencia universitaria con el alumnado del Grado de Ciencias de la Actividad Física y del Deporte de segundo curso, se encuentran carencias en esta materia en la mayoría de los alumnos/as que plasman estas herramientas y actitudes solo por una «meritocracia relativa» o esperando algo a cambio. En consecuencia, se plantea unas herramientas de trabajo para educación física escolar, lúdica, a través de una metodología gamificada y cercana a la realidad del alumnado, que hace de estos contenidos una experiencia vital.post-print242 K