Construction of polynomial spline spaces over quadtree and octree T-meshes for its application in isogeometric analysis

[EN]We present a new strategy for construction spline spaces over hierarchical T-meshes with quad- and octree subdivision scheme.MINECO y FEDER; CONACYT-SENER Project, Fondo Sectorial, contract: 16372

Analysis of several objective functions for optimization of hexahedral meshes

Ministerio de Educación, Cultura y Deporte MINECO; FEDE

Strategies for optimization of hexahedral meshes and their comparative study

In this work, we study several strategies based on different objective functions for optimization of hexahedral meshes. We consider two approaches to construct objective functions. The first one is based on the decomposition of a hexahedron into tetrahedra. The second one is derived from the Jacobian matrix of the trilinear mapping between the reference and physical hexahedral element. A detailed description of all proposed strategies is given in the present work. Some computational experiments have been developed to test and compare the untangling capabilities of the considered objective functions. In the experiments, a sample of highly distorted hexahedral elements is optimized with the proposed objective functions, and the rate of success of each function is obtained. The results of these experiments are presented and analyzed.Secretaría de Estado de Universidades e Investigación del Ministerio de Economía y Competitividad del Gobierno de España; Programa de FPU del Ministerio de Educación, Cultura y Deporte; Programa de FPI propio de la ULPGC; Fondos FEDE

Spline parameterization method for 2D and 3D geometries based on T-mesh optimization

[EN]We present a method to obtain high quality spline parameterization of 2D and 3D geometries for their use in isogeometric analysis. As input data, the proposed method demands a boundary representation of the domain, and it constructs automatically a spline transformation between the physical and parametric domains. Parameterization of the interior of the object is obtained by deforming isomorphically an adapted parametric T-mesh onto the physical domain by applying a T-mesh untangling and smoothing procedure, which is the key of the method. Mesh optimization is based on the mean ratio shape quality measure. The spline representation of the geometry is calculated by imposing interpolation conditions using the data provided by one-to-one correspondence between the meshes of the parametric and physical domains. We give a detailed description of the proposed technique and show some examples. Also, we present some examples of the application of isogeometric analysis in geometries parameterized with our method.Secretaría de Estado de Universidades e Investigación del Ministerio de Economía y Competitividad del Gobierno de España y fondos FEDER; Programa de FPU 12/00202 del Ministerio de Educación, Cultura y Deporte; Programa de FPI propio de la Universidad de Las Palmas de Gran Canari

Wind field simulation with isogeometric analysis

[EN]For wind field simulation with isogeometric analysis, firstly it is necessary to generate a spline parameterization of the computational domain, which is an air layer above the terrain surface. This parameterization is created with the meccano method from a digital terrain model. The main steps of the meccano method for tetrahedral mesh generation were introduced in [1, 2]. Based on the volume parameterization obtained by the method, we can generate a mapping from the parametric T-mesh to the physical space [3, 4]. Then, this volumetric parameterization is used to generate a cubic spline representation of the physical domain for the application of isogeometric analysis. We consider a mass-consistent model [5] to compute the wind field simulation in the three-dimensional domain from wind measurements or a wind forecasted by a meteorological model (for example, WRF or HARMONIE). From these data, an interpolated wind field is constructed. The mass-consistent model obtains a new wind field approaching the interpolated one, but verifying the continuity equation (mass conservation) for constant density and the impermeabilitycondition on the terrain. This adjusting problem is solved by introducing a Lagrange multiplier, that is the solution of a Poisson problem. The resulting field is obtained from the interpolated one and the gradient of the Lagrange multiplier. It is well known that if we use classical Lagrange finite elements, the gradient of the numerical solution is discontinuous over the element boundary. The advantage of using isogeometric analysis with cubic polynomial basis functions [6, 7] is that we obtain a C2 continuity for the Lagrange multiplier in the whole domain. In consequence, the resulting wind field is better approximated. Applications of the proposed technique are presented.Ministerio de Economía y Competitividad del Gobierno de España; Fondos FEDER; CONACYT-SENE

Natural language processing for web browsing analytics: Challenges, lessons learned, and opportunities

In an Internet arena where the search engines and other digital marketing firms’ revenues peak, other actors still have open opportunities to monetize their users’ data. After the convenient anonymization, aggregation, and agreement, the set of websites users visit may result in exploitable data for ISPs. Uses cover from assessing the scope of advertising campaigns to reinforcing user fidelity among other marketing approaches, as well as security issues. However, sniffers based on HTTP, DNS, TLS or flow features do not suffice for this task. Modern websites are designed for preloading and prefetching some contents in addition to embedding banners, social networks’ links, images, and scripts from other websites. This self-triggered traffic makes it confusing to assess which websites users visited on purpose. Moreover, DNS caches prevent some queries of actively visited websites to be even sent. On this limited input, we propose to handle such domains as words and the sequences of domains as documents. This way, it is possible to identify the visited websites by translating this problem to a text classification context and applying the most promising techniques of the natural language processing and neural networks fields. After applying different representation methods such as TF–IDF, Word2vec, Doc2vec, and custom neural networks in diverse scenarios and with several datasets, we can state websites visited on purpose with accuracy figures over 90%, with peaks close to 100%, being processes that are fully automated and free of any human parametrizationThis research has been partially funded by the Spanish State Research Agency under the project AgileMon (AEI PID2019-104451RBC21) and by the Spanish Ministry of Science, Innovation and Universities under the program for the training of university lecturers (Grant number: FPU19/05678

The Meccano Method for Mesh Generation and Solid Parameterization

[EN]In this conference, we present the main advances in the meccano method, which was introduced by the authors in 2006 for tetrahedral mesh generation

Germinación, fitotoxicidad y efecto nematicida de la vinaza de vino, un subproducto de la industria vinícola

The objective of this study was to determine the effect of wine vinasse (WV), the final byproduct obtained from distillation of the fermentation wine, on plants and nematodes through germination, phytotoxicity and nematode survival tests. Before conducting the bioassays, fertility parameters of two WV samples from different years were analyzed and compared. Six WV solutions were applied to obtain the most effective ones with nematicidal properties without compromising plant growth. For this purpose, two very different plant-parasitic nematodes, Meloidoyne incognita and Xiphinema index, both widespread in vineyards were analyzed. The effects of these WV doses were tested on seed and plant growth in germination and phytotoxicity bioassays. The doses 1, 3 and 5 % were applied to soils naturally infested by root-knot nematodes for biodisinfestation in the laboratory. As a result, the number of Meloidogyne juveniles was significantly reduced, while other non-parasitic nematodes and enchytraeids were less affected. Marmande tomato plants grown in biodisinfested soil showed a reduction in galling index (0 at 3 & 5 % solutions). Our results show that WV contributes to reducing plant-parasitic nematode populations without phytotoxic side effects. The fertilizing effect of WV on Marmande tomato and white mustard plants indicates that it can be introduced into horticultural cropping systems. The valorization of WV as an organic resource for biodisinfestation of agricultural soils may help to solve accumulation problems and contribute to a circular economy by reducing waste. The characterization of both WV and agrarian soil will help to define the suitability of such actions prior to applying this organic amendment.El objetivo de este estudio fue determinar el efecto de la vinaza de vino (VV), el subproducto final obtenido de la destilación del vino de fermentación, sobre plantas y nematodos mediante pruebas de germinación, fitotoxicidad y supervivencia de nematodos. Antes de realizar los bioensayos, se analizaron y compararon los parámetros de fertilidad de dos muestras de VV de diferentes años. Se aplicaron seis soluciones de VV con el fin de obtener las más eficaces con propiedades nematicidas sin comprometer el crecimiento de las plantas. Para ello, se analizaron dos nematodos fitoparásitos muy diferentes, Meloidoyne incognita y Xiphinema index, ambos muy extendidos en los viñedos. Se probaron los efectos de estas dosis de VV sobre el crecimiento de las semillas y las plantas en bioensayos de germinación y fitotoxicidad. Las dosis 1, 3 y 5 % se aplicaron a suelos infestados naturalmente por nematodos formadores de nódulos para su biodesinfestación en laboratorio. El resultado fue que el número de juveniles de Meloidogyne se redujo significativamente, mientras que otros nematodos no parásitos y los enquitréidos se vieron menos afectados. Las plantas de tomate Marmande, cultivadas en suelo biodesinfectado, mostraron una reducción del índice de nodulación (0 en soluciones al 3 y al 5 %). Estos resultados muestran que VV contribuye a reducir las poblaciones de nematodos parásitos de las plantas sin efectos fitotóxicos secundarios. El efecto fertilizante de VV en las plantas de tomate Marmande y mostaza blanca indica que puede ser introducido en los sistemas de cultivos hortícolas. La valorización del VV como recurso orgánico para la biodesinfestación de suelos agrícolas puede ayudar a resolver los problemas de acumulación y contribuir a una economía circular al reducir los residuos. La caracterización de ambos, VV y suelo agrario, ayudará a definir la idoneidad de tales acciones antes de aplicar esta enmienda orgánica

DISEÑO E IMPLEMENTACIÓN DE UN PROTOTIPO PARA EL REGISTRO Y VERIFICACIÓN DE ACTIVOS FIJOS UTILIZANDO PLATAFORMA ANDROID Y TECNOLOGÍA NFC

Este documento plantea una propuesta de prototipo e implementación de una aplicación, construida en plataforma Android utilizando tecnologías NFC. La motivación para la elaboración de la aplicación es la problemática de  la validación y control de flujo de activos fijos, bastante común en la actualidad. Con este desarrollo se busca proporcionar una solución a la tarea del registro y validación de entrada y salida de elementos físicos, que estarán relacionados con información almacenada en una base de datos donde se asociarán con una persona, en un lugar en específico. En el desarrollo de la aplicación se implementó una arquitectura de software basada en cliente-servidor contando con elementos tipo web y móvil, y acoplando diferentes tecnologías que convergen a un único servicio. Como trabajo futuro se destacara la posibilidad de extender la aplicación a cualquier organización que la requiera, también deben explorarse nuevas metodologías de seguridad en general para las etiquetas NFC que permitan  generar una capa de seguridad eficiente y robusta.  Finalmente, se obtiene como resultado una versión funcional del aplicativo probada en la Universidad Distrital Francisco José de Caldas de la ciudad de Bogotá en Colombia para el control de entrada y salida de dispositivos electrónicos, con resultados satisfactorios