Realistic Cloth Animation

In this paper we present a model for the realistic simulation of the mechanical behavior of cloth based on the Finite Elements Method. The use of this method in a material with the elastic properties of cloth has some problems of convergence to which we propose a solution in this work

A Stable Hybrid Potential–SPH Technique to Enforce the Fluid Incompressibility

The SPH method has extensively used in fluid flow simulation. Through SPH the fluid is modelled by a particles system whose mutual interaction is weighed by a function, named kernel function, whose limits define the neighbouring of each particle. In spite of the high capabilities of SPH for simulate complex environments, it shows shortcomings specially if the fluid is subject to high changes in the pressure, the velocity and the density as occur in phenomena such as shock–tube, blast–wave or in the boundary and discontinuities where the number of neighbour particles is relatively low. In this case, the pressure gradient is inaccurate. As consequence, the simulation is instable with an erratic behaviour of particles. To avoid this problem, we propose a hybrid technique. This one consists in formulating the pressure gradient from a potential defined on each particles pair. Thus, the pressure gradient is immune to the low number of neighbour particles. Also, our proposal allows enforcing the fluid incompressibility. To show the improvements obtained we will carry out a set of simulationMinisterio de Economía y Competitividad TIN2016-76953-C3-2-

Diseño del Modelo Navegacional para Sistemas de Tratamiento de Bibliotecas Digitales

Los sistemas de tratamiento de bibliotecas digitales nacen como sistemas complejos en los que se mezclan importantes requisitos de almacenamiento de información, debido a los múltiples medios que se usan en ellos, con grandes necesidades funcionales. Pero además en el entorno de las bibliotecas digitales se añaden unas necesidades, que son propias de las aplicaciones multimedia y páginas web, como son el uso de los enlaces y el ofrecer una atractiva interfaz de usuario. Estas nuevas necesidades se hacen patentes principalmente en la fase de diseño de la aplicación, puesto que es en ella donde se le añadirán a la aplicación. En este trabajo, se propone cómo se puede incorporar el diseño de los aspectos de navegación a una aplicación

Aplicación Integrada de la Biblioteca Digital del Patrimonio Histórico Andaluz

En este trabajo se describen las necesidades del Instituto Andaluz de Patrimonio Histórico para desarrollar el Sistema de Información Integrado de Patrimonio Histórico Andaluz. El objetivo es crear un sistema de acceso y gestión uniforme a la información dispersa en diversas bases de datos que han sido creadas por grupos de trabajo independientes. Para ello, se propone un modelo de arquitectura, basado en XML, que permite el acceso uniforme a bases de datos heterogéneas y distribuidas

Requisitos de almacenamiento de información e identificación de actores para una biblioteca digital de bienes muebles

Desarrollar una biblioteca digital no es una tarea sencilla. En ella intervienen técnicos y expertos que deben tener una fluida comunicación que permita que el sistema resultante se adecue a las necesidades del usuario. Este trabajo presenta las necesidades de almacenamiento que requiere una biblioteca digital para la gestión del patrimonio mueble andaluz, así como la identificación de los actores que van a interactuar con el sistema. Al final del trabajo se presenta una aproximación metodológica para el desarrollo de sistemas para el tratamiento de bibliotecas digitales que se está elaborando en el contexto del proyecto de investigación MADEIRA(Metodologías y Arquitecturas para la Difusión Electrónica de Información por la Red )Ministerio de Ciencia y Tecnología Madeira TIC2000-1673-C06-0

Hands-free wearable system for helping in assembly tasks in aerospace

Las operaciones de mantenimiento tienen un gran impacto en la seguridad y esperanza de vida de cualquier producto, especialmente en ciertas aplicaciones dentro de la industria aeronáutica que tiene que pasar procedimientos muy rigurosos de seguridad. Los sistemas de ayuda llevables (wearable) pueden ayudar a reducir costes y tiempo de trabajo guiando a los operarios en tareas difíciles. El propósito de este trabajo es presentar un sistema de guiado de manos libre y llevable para soporte y ayuda de operarios en tareas de ensamblaje y verificación dentro del campo de la aeronáutica. El operario es capaz de pedir información al sistema sobre una tarea específica de un modo no invasivo así como pedir asistencia técnica al líder del equipo. El sistema desarrollado ha sido probado en una compañía aeronáutica (Airbus Military) y se ha evaluado su implementación en ciertas tareas de ensamblaje. La conclusión de las pruebas ha sido que el sistema ayuda a los operarios a realizar sus tareas de una manera más rápida, precisa y segura.Maintenance operations have a great impact on the safety and life expectancy of any product. This is especially true for certain applications within the aerospace industry, which must pass rigorous security checking procedures. Wearable helping systems can help to reduce costs and working time by guiding workers in some specifi c and diffi cult tasks. The purpose of this work is developing a handless and wearable guided system that supports and helps workers in assembly and verifi cation tasks within the aeronautic fi eld. The worker is able to request information for the specifi c task in a non invasive way and also ask the Team Leader for real time technical support and assistance. The system developed has been tested in an aeronautic company (Airbus Military) and its implementation in specifi c assembly tasks assessed. It was found that the proposed system can help workers to make their tasks faster, more accurate and more secure

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

A new Potential-based SPH Method

In Computer Graphics the fluid simulation plays a relevant role. Amongst the existing methods, the SPH method is highlighted by its simplicity, versatility and adaptability. Nevertheless, several research show some limitations that affect both the stability and the realism of simulation. These limitations are related with the calculation of the mass density and the pressure gradient, mainly when the number of neighbouring particles is low as boundary and discontinuities. Also, the simulation realism is compromised when the incompressibility constraint is enforced and the fluid heating is not dissipated. To overcome these limitations, we present a new technique to simulate the fluid flow. It involves of a hybrid technique that allow us to calculate a stable pressure gradient and the mass density even when the number of neighbouring particle is low. Also, we directly control the incompressibility and dissipate the fluid heating with accurate. Thus, we obtain stable and realistic fluid simulation, even with higher time steps.Ministerio de Economía y Competitividad TIN2013-46928-C3-3-RMinisterio de Economía y Competitividad TIN2015-71938-RED

An Improved Parallel Technique for Neighbour Search on CUDA

In Computer Graphics is usual the modelling of dynamic systems through particles. The simulation of liquids, cloths, gas, smoke... are highlighted examples of that modelling. In this scope, is particularly relevant the procedure of neighbour particles searching, which represents a bottleneck in terms of computational cost. One of the most used searching techniques is the cell– based spatial division by cubes, where each cell is tagged by a hash value. Thus, all particles located into each cell have the same tag and are the candidate to be neighbours. The most useful feature of this technique is that it can be easily parallelized, what reduces the computational costs. Nevertheless, the parallelizing process has some drawbacks associated with data memory management. Also, during the process of neighbour search, it is necessary to trace into the adjacent cells to find neighbour particles, as a consequence, the computational cost is increased. To solve these shortcomings, we have developed a method that reduces the search space by considering the relative position of each particle in its own cell. This method, parallelized using CUDA, shows improvements in processing time and memory management over other “standard” spatial division techniques. (see http://www.acm.org/about/class/class/2012)Ministerio de Economía y Competitividad TIN2016-76953-C3-2-RMinisterio de Economía y Competitividad TIN2015-71938-RED

More Stable SPH-based Fluid Simulation

The simulation of fluid is a field largely discussed, from the viewpoint of engineering, in the so-called compu tational fluid dynamics (CFD). A problem that occurs repeatedly in the literature of CFD is the stability of the simulation. One of the elements that introduce instability in any CFD model is the temporal integration method. Among the most commonly used CFD techniques, both in the field of engineering and in the computer graphics, is SPH, which is particularly relevant to its computational simplicity. However, this technique adds stability pro blems due to the treatment of viscous and pressure terms arising from the formulation of Navier–Stokes. SPH also introduces greater instability by the need to use interpolation functions appropriate to the phenomena that occur in fluid dynamics. We present solutions to these four problems of inestability mentioned: treatment of the terms of pressure and viscosity that appear in the Navier–Stokes, the formulation of the characteristic interpolation function of SPH and treatment of temporal integrationMinisterio de Educación y Ciencia TIN2007-67843-C06-03Ministerio de Educación y Ciencia TIN2010-20057-C03-0