3,956 research outputs found

    Implementación de un algoritmo genético paralelo sobre HW gráfico de última generación

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    Los algoritmos genéticos (AGs) son procedimientos de búsqueda y optimización inspirados por la simplicidad y efectividad del proceso de la evolución natural de las especies. Al igual que ocurre en la naturaleza, basan su éxito en la supervivencia de los individuos más aptos de una población. En este caso, un individuo es una solución potencial del problema, y se implementa como una estructura de datos. Los AGs trabajan sobre poblaciones de soluciones que evolucionan mediante la aplicación de operadores genéticos (selección, cruce y mutación) adecuados al problema específico que intentan resolver. Uno de los rasgos esenciales de los AGs es su paralelismo implícito puesto que, al igual que la evolución natural, trabajan con poblaciones enteras, no con sus individuos integrantes en particular. Los sistemas actuales cuentan con potentes tarjetas gráficas, frecuentemente programables, que permanecen inactivas durante la ejecución de aplicaciones no gráficas. Dichas tarjetas cuentan con un procesador de naturaleza paralela, que las hace especialmente indicadas para la ejecución de AGs. Este trabajo es una propuesta para aprovechar un recurso hardware habitualmente inactivo para implementar, en un sistema monoprocesador, algún tipo de topología de AGs paralelos. Obtenemos así mejoras -tanto en la calidad de las soluciones como en el tiempo de ejecución- con respecto a la ejecución secuencial del AG sobre la CPU. [ABSTRACT] Genetic algorithms (GAs) are optimization techniques which imitate the way that nature selects the best individuals (the best adaptation to the environment) to create descendants which are more highly adapted. The first step is to generate a random initial population, where each individual is represented by a character chain like a chromosome and with the greatest diversity, so that this population has the widest range of characteristics. Each individual represents a solution for the targeted problem. Then, each individual is evaluated using a fitness function, which indicates the quality of each individual. Finally, the best-adapted individuals are selected to generate a new population, whose average will be nearer to the desired solution. This new population is created making use of three operators: selection, crossover and mutation.One of the major aspects of GA is their ability to be parallelised. Indeed, because natural evolution deals with an entire population and not only with particular individuals, it is a remarkably highly parallel process. Nowadays computer systems incorporate powerful graphic cards that are commonly idle during a normal execution process of most of the optimization algorithms. Modern graphic cards use a pipelined streaming architecture to perform a significant part of the rendering process. Two stages in the pipelined process are programmable in current graphics hardware. The vertex engine is used to perform transformations on the vertex attributes (normal, position, color, texture, ...). On the other hand, the fragment engine is used to transform the fragments that form the different polygons. Both engines are extremely parallel, processing several elements in parallel and making extensive use of SIMD units. In this work we have presented a parallel implementation of a GA using a GPU. We have implemented not only three well know benchmarks problems with excellent Speed-up results, but also a novel implementation of an algorithm for solving defectives problems proposed in the literature

    Cataract surgery astigmatism incisional management. Manual relaxing incision versus femtosecond laser-assisted arcuate keratotomy. A systematic review

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    Purpose: This systematic review aims to compare corneal astigmatism correction in cataract surgery through corneal relaxing incision, manually and femtosecond laser assisted. Methods: The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. We used PubMed, Scopus, and Web of Science (WOS) as databases from January 2010 to March 30, 2021. Patients with keratoconus, corneal ectasia, and a previous history of eye surgery were excluded because our aim was to analyze only healthy eyes. Results: A total of 1025 eyes were evaluated from 946 patients (mean age was 68.90 ± 5.12) in manual incision group articles, while 1905 eyes of 1483 patients (mean age was 65.05 ± 4.57) were evaluated in femtosecond laser arcuate keratotomy (FLAK) articles. The mean uncorrected distance visual acuity (UDVA) was 0.19 ± 0.12 and 0.15 ± 0.05 logMAR for manual incision and FLAK articles, respectively (p = 0.39). The mean correction index (CI) was similar in both groups: 0.77 ± 0.18 in manual incision and 0.79 ± 0.17 in femtosecond laser assisted incision (p = 0.70). Refractive stability was found after 3 months and no serious complications were reported during the follow-up in any group. Conclusion: Both techniques are safe and moderately effective in corneal astigmatism correction in cataract surgery. FLAK represents a more precise and predictable approach. However, since visual and refractive outcomes appear to be similar in both cases, the cost-benefit analysis is controversial

    Update of the Urban Heat Island of Madrid and Its Influence on the Building's Energy Simulation

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    Despite great advances on building energy evaluation, available climate data does not include the effects of the Urban Heat Island (UHI). This phenomenon, which increases the temperature in urban areas, is variable in both time and space, and implies an important lack of accuracy when simulating within an urban context. During this research the relevance of the UHI in relation to the dwellings energy performance has been confirmed, as well as the existing barriers to integrate the current UHI representations into the dynamic energy simulation process. Therefore, it is necessary to carry out an update of the existing models, in order to implement it into the energy evaluation process. In this work, as a first stage of the study and based on current techniques of geolocation and the use of Geographic Information Systems (GIS), it is established a methodology to acquire automatically an update of the UHI through isotherm maps. It is aimed to set up the starting point from which the integration of the UHI into the energy simulation process will happen

    Validation of H-P2PSIP, a scalable solution for interoperability among different overlay networks

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    This paper reports the results of experiments from an implementation of H-P2PSIP, a hierarchical overlay architecture based on the ongoing work in the IETF P2PSIP Working Group. This architecture allows the exchange of information among different independent overlay networks through the use of a two-layer architecture based on super-peers and hierarchical identifiers. The validation of this proposal is based on a Linux based real implementation where we have used four different scenarios with 1,000 peers in order to perform different experiments. We have obtained results for different parameters such as routing performance (number of hops), delay, routing state (number of overlay routing entries) and bandwidth consumption.This research was supported in part by the European Commission Seventh Framework Programme under grant agreement n 25774 (TREND Network of Excellence), Comunidad de Madrid grant S-2009/TIC-1468 (MEDIANET project) and Spanish MICINN grant TEC2011-29688-C02-02 (eeCONTENT project).Publicad

    Planificación de MIPYME Soluciones Integrales Tecnológicas “SOINTEC”, en la Ciudad de Managua en el periodo de 02 de Septiembre del 2015 al 03 de Febrero del 2016

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    El presente trabajo de seminario se aplica todas las acciones necesarias para la puesta en marcha de una microempresa Soluciones integrales Tecnológicas, se utilizó la investigación descriptiva transversal y analítica, apoyándose en fuentes primarias y secundarias como literatura de proyectos, encuestas y entrevistas para el desarrollo de ciertos objetivos específicos. Adicionalmente, se utilizaron herramientas de administración de proyectos tales como: MS-Project, WBS chart pro, plantillas para la elaboración de los diferentes planes de gestión, Microsoft Excel, Microsoft Word, y la utilización del PMBOK que permitió contar con una guía clara de cómo administrar un proyecto. El presente plan de proyecto cuenta con un total de 12 entregables, se espera sean completadas en un lapso aproximado de 209 días. El equipo del proyecto está conformado por un director de proyecto, 3 ingenieros de sistemas y un estudiante de derecho. El trabajo se desarrolla aplicando las buenas prácticas de la Gerencia de Proyectos, sugeridas en el PMBOK, definiendo el alcance y la estructura detallada del trabajo (EDT); la estimación de los costos y el presupuesto financiero; la identificación, análisis y planificación de respuesta a los riesgos; la planificación y gestión de los interesados y la planificación de la calidad seguidamente de las conclusione

    Influence of Mindfulness on Levels of Impulsiveness, Moods and Pre-Competition Anxiety in Athletes of Different Sports

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    Training in emotional regulation skills is one of the most important resources for the adaptation of athletes to contexts of sports pressure, especially during competitions. This study explored the effects of a mindfulness programme (Flow Meditation) on levels of impulsivity, mood and pre-competition anxiety-state in a sample of athletes (N = 41, 22.83 ± 5.62 years). Participants were randomly assigned to an intervention group (N = 21; 14 males and 7 females) which received the intervention over 10 weeks (a weekly session) and a control group (wait-list; N = 20; 13 males and 7 females). The variables under study were assessed through different questionnaires at pre- and post-test (T1–T2) in both groups. The mindfulness intervention was effective in reducing impulsivity (cognitive (t = −4.48, p ≤ 0.001, Cohen’s d = 1.40), both motor (t = −4.03, p ≤ 0.001, Cohen’s d = 1.20) and unplanned (t = −5.32, p ≤ 0.001, Cohen’s d = 1.66)), mood (tension (t = −4.40, p ≤ 0.001, Cohen’s d = 1.37), depression (t = −4.56, p ≤ 0.001, Cohen’s d = 1.42), anger (t = −7.80, p ≤ 0.001, Cohen’s d = 2.47), somatic anxiety (t = −5.28, p ≤ 0.001, Cohen’s d = 1.65), and cognitive anxiety (t = −6.62, p ≤ 0.001, Cohen’s d = 2.07) in the intervention group compared to the control group and with large to very large effect sizes. Mindfulness is a factor that enhances athletes’ ability to cope with high sport pressure and the healthy management of competition (e.g., fear of failure), or with their daily life

    Ratón de campo – Apodemus sylvaticus (Linnaeus, 1758)

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    Mamíferos - Orden Rodentia - Familia Muridae en la Enciclopedia Virtual de Vertebrados Españoles, http://www.vertebradosibericos.org/.A comprehensive review of the natural history of the Wood Mouse Apodemus sylvaticus in Spain.Peer reviewe

    Topillo campesino – Microtus arvalis (Pallas, 1779)

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    Mamíferos - Orden Rodentia - Familia Arvicolidae en la Enciclopedia Virtual de Vertebrados Españoles, http://www.vertebradosibericos.org/.A comprehensive review of the natural history of the Common Vole Microtus arvalis in Spain.Peer reviewe

    Propuestas de normas para la creación de una figura de inspección para la aplicación de medidas de igualdad en una empresa

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    La Ley Orgánica 3 /2007 para la igualdad efectiva entre hombres y mujeres, hace referencia a una Ley formalmente real, pero inexistente en la práctica. A través de esta iniciativa se propone la creación de una Ley Ordenadora de la Inspección de Igualdad en las empresas creando para ello la figura de un inspector de igualdad, como un servicio público destinado a garantizar el cumplimiento de la igualdad en el ámbito laboral. A esta novedosa figura le corresponderá ejercer la vigilancia del cumplimiento de las normas en materia de igualdad y exigir las responsabilidades pertinentes, así como el asesoramiento y, en su caso, arbitraje, mediación y conciliación en dichas materias, que ha de efectuar de conformidad con los principios del Estado social y democrático de Derecho que consagra la Constitución Española. El único fin perseguido a través de esta propuesta es alcanzar el verdadero objeto de la mencionada Ley, esto es, hacer efectivo el derecho de igualdad de trato y de oportunidades entre mujeres y hombres

    La recepción de Miguel Hernández en la música flamenca: estudio de literatura comparada

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    Este trabajo de investigación nace del interés en estudiar el acoplamiento de la poesía de Miguel Hernández (1910-1942) con la música flamenca, y por este motivo, hemos recopilado toda aquella discografía cuyas letras están tomadas del corpus poético de este escritor, cuya elección se debe a varias razones, entre las cuales destacan la sencillez y profundidad de sus poemas, el carácter reivindicativo de sus letras y el homenajearlo por la admiración que le profeso. En consecuencia, esta tesis alejada de una vertiente purista literaria, pretende ser un enlace de unión entre la música flamenca y la literatura, realizando en este trabajo un paralelismo comparativo entre las letras flamencas, procedentes de la poesía popular, y la lírica de Miguel Hernández. Junto a este análisis comparativo, estudio como el cantaor siente la necesidad de transformar la poesía hernandiana y convertirla en una auténtica letra flamenca, en ese proceso de variación que sufre el cante. Debemos considerar que unas mismas letrillas flamencas pueden ser interpretadas de manera diferente por el mismo intérprete según la capacidad memorística, el contexto social y cultural, el escenario donde se encuentre... y aunque en este estudio me he centrado principalmente en la grabación sonora y no en el cante en vivo, por lo que el registro de audio es inamovible a tales elementos de variabilidad, es interesante suponer que antes de llegar al producto final ha tenido que pasar por una serie de modificaciones. Los principales mecanismos empleados por los cantaores en esta transformación de la poesía hernandiana a unas auténticas letrillas para el cante son la adición de versos y estrofas del propio Hernández e incluso de otros autores, la supresión de versos, palabras e incluso estrofas y, por último, la repetición. En definitiva, junto a este profundo análisis comparativo de la poética hernandiana con las letrillas del cante flamenco y el estudio del acoplamiento de una lírica culta a unos moldes preestablecidos por el cante, esta tesis podría ser modelo para estudios posteriores de otros poetas cultos que serían reflejados a través de artículos o monográficos, de los mismos. Por tanto, todo este amplio trabajo de investigación podría ser retomado por otros estudiosos de la materia, dejando abierta una amplia línea de investigación.This research arises from the interest of studying the coupling of the poetry of Miguel Hernandez (1910-1942) with flamenco music, and for this reason, we have compiled all discography with lyrics that are taken from the poetic corpus of this writer, whose election is due to several reasons, among which we can highlight the simplicity and depth of his poems, the vindictive nature of his lyrics and the aim to honor him with admiration that I profess to him. Consequently, this thesis is far from a literary purist side, and aims to be a binding link between the flamenco music and literature, making during this work a comparative parallel between the Flamenco letters, from folk poetry, and the poetry of Miguel Hernández. Along with this comparative analysis, I study as the singer feelings that need to transform the poetry from Miguel Hernández, and make it real flamenco lyrics, in the process of change experienced by the singing. We must consider that the same flamenco lyrics can be interpreted differently by the same artist depending of his memory capacity, the social and cultural context, the scenario where he is ... and although in this study I focused mainly in the sound recording and not in the live singing, so audio recording is an immovable element against such variability, it is interesting to assume that before arriving the final product, it has been passing through a number of changes. The main mechanisms used by singers in this transformation of the genuine poetry of Miguel Hernández to a song, is the addition of verses of Hernández and even others, the elimination of lines, words and even verses and finally, the use of the repetition. In short, with this deep comparative analysis of Miguel Hernández poetic with lyrics of flamenco singing and the study of the coupling of a cultured lyrical singing preset molds, this thesis could be a model for future studies of other cult poets that would be reflected by articles or monographics of theirselves. Therefore, all this extensive research work could be taken up by other scholars in the field, and therefore leaving a wide range of research open for the future
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