Rubén Jesús García Hernandez

• PhD
• Researcher at Leibniz Supercomputing Centre

Virtual Reality (VR) can be found in many fields including art history, education, research, and industry 4.0. Next to lightweight Head-Mounted Displays there are also VR installations, such as immersive 3D screens, large-scale displays, and CAVE systems, that are used in research, scientific visualization, and also the automotive industry. These s...

Traditional usage models of Supercomputing centres have been extended by High-Throughput Computing (HTC), High-Performance Data Analytics (HPDA) and Cloud Computing. The complexity of current compute platforms calls for solutions to simplify usage and conveniently orchestrate computing tasks. These enable also non-expert users to efficiently execut...

The LEXIS Weather and Climate Large-scale Pilot will deliver a system for prediction of water-food-energy nexus phenomena and their associated socio-economic impacts. The system will be based on multiple model layers chained together, namely global weather and climate models, high-resolution regional weather models, domain-specific application mode...

We describe a suite of open source virtual reality programs which can be used to visualize the results of chemical simulations of various types (including access to NOMAD, the largest database of materials science compounds). The programs target virtual reality environments at different price points (M€ CAVE-like11CAVETM is a trademark of the Unive...

We present a multi-platform tool that allows us to explore materials in Virtual Reality (VR) which has been developed within the Novel Materials Discovery (NOMAD) Laboratory, a European Centre of Excellence [NOMAD]. The so far implemented functionality covers (Fig. 1) crystal structures, Fermi surfaces, molecular-dynamics trajectories, and electron...

We describe a free-software virtual reality system which provides material scientists with a tool to more easily study simulations of chemical systems at the atomic and molecular levels, and which is compatible with the NOMAD infrastructure (an international, open repository which is developing advanced analysis techniques and contains millions of...

This paper describes how tablets can be used to increase the interaction possibilities of virtual reality applications running on CAVE-like 1 environments. A use case is presented using the genome comparison software 3DScover. The tablet interface has been introduced in a user-centric development environment. Multiple user studies have guided the e...

This paper describes how tablets can be used to increase the interaction possibilities of virtual reality applications running on CAVE-like1 environments. A use case is presented using the genome comparison software 3DScover. The tablet interface has been introduced in a user-centric development environment. Multiple user studies have guided the ev...

Legends of Girona is a serious game which can be used to teach local history to students in the province of Girona in Spain. The game is a graphic adventure taking place in both present-day and medieval Girona. We describe in this paper the design of the game, including aspects related to artificial intelligence, advanced computer graphics, exergam...

This paper presents an analysis of the overestimation bias in common used filtering kernels in the context of photon mapping density estimation. We use the joint distribution of order statistics to calculate the expected value of the estimators of irradiance, and show that the estimator provided by the cone filter is not consistent unless the slope...

This paper describes a serious game intended to teach singing to children. The system shows the students a virtual world they can explore, and the evolution of the world is based on their performance. Automatic content generation tecniques are used to present the player with different exercises, and their singing is evaluated using state of the art...

Regular health monitoring of bridges is a vital process to prevent serious structural damage. Marker-based systems, which follow the trajectory of objects by placing a well-characterized pattern on their surface and identify them on photos or videos taken of these objects, have proven to be a cheap and flexible alternative for such tasks. In this w...

Maintaining and restoring health is a basic aspect of well being. On the other hand, serious games is an emerging technology growing in importance for specialized training, taking advantage of 3D games and game engines in order to improve the realistic experience of users. Thus, according to the advancement of technology and the desire to achieve g...

This paper describes different interactive, non photorealistic techniques which can be easily applied to video games. Based on a study of art and games, an emphasis is put on considering NPR tools as basic elements to provide different styles and moods, to convey different emotional and experiential representations of a game. We restrict ourselves...

In this paper we propose to create virtual glades of flowers using kinect gestures. The user gestures are read and reinterpreted by the kinect interface. Once the gesture is made, and a correspondence to the parameter space of the flower model is done, it is transmitted to a web server which contains a 3Gmap L-system application. 3Gmap L-systems (a...

As no civil infrastructure can escape aging and deterioration, health monitoring can prevent and report serious structural damage. With the rapid evolution of computer vision algorithms, optical-based systems become an increasingly feasible option for automatic monitoring. This paper proposes a cheap and flexible standalone system based on marker t...

This paper presents an analysis of the irradiance estimator often used in photon mapping algorithms and concludes that the classical approach with a constant kernel overestimates the correct value. We propose a new estimator that solves this problem and provide both theoretical and empirical studies to verify it.

Advanced graphics effects can be difficult to create and implement by nonexperts. We present here multiplatform, multigame engine libraries, designed to simplify the use of efficient state-of-the-art computer graphics algorithms in the fields of geometry and illumination. A summary of our experiences updating and porting the libraries is included,...

In this chapter, we present a state-of-the-art report on serious games dealing with e-health in a broad sense, including medicine, nursing, health care, and physical exercise. The games have been classified according to their main purpose (entertainment, teaching, or health), stages of the disease being treated and the type of users of the system (...

We address the speedup of the nume- rical solution of shallow water systems in 2D do- mains by using modern Graphics Processing Units. We have considered a first order well-balanced finite volume numerical scheme for 2D shallow water sys- tems. The potential data parallelism of this method has been identified and an efficient implementation of this...

Abstract This article presents an optimized ray tracing algorithm which improves standard existing algorithms. In order to do this, this algorithm processes simultaneously a large set of rays and carries out a single traversal of the spatial indexing of the scene with all rays, which allows us to efficiently make use of hardware SIMD functionality...

This paper introduces a new BRDF sampling method with reduced variance, which is based on a hierarchical adaptive PDF. This PDF also is based on rejection sampling with a bounded average number of trials, even in regions where the BRDF exhibits high variations. Our algorithm works in an appropiate way with both physical, analytical and measured ref...

Tesis Univ. Granada. Departamento de Lenguajes y Sistemas Informáticos. Leída el 23 de julio de 2009

Este artículo presenta un método de estimación de densidades basado en rayos que ha sido implementado com- pletamente en la GPU. La estimación de densidades basada en rayos reduce el sesgo de los enfoques clásicos basados en fotones aunque tiene un costo computacional más alto. Proponemos algoritmos y estructuras de datos para la implementación en...

This paper introduces a new BRDF sampling method with reduced variance, which is based on a hierarchical adaptive parameterless PDF. This PDF is based also on rejection sampling with a bounded average number of trials, even in regions where the BRDF does exhibit high variations. Our algorithm works in an appropiate way with both physical and analyt...

Global illumination solutions provide a very accurate representation of illumination. However, they are usually costly to calculate. In the common case of quasi-static scenario, in which most of the scene is static and only a few objects move, most of the illumination can be reused from previous frames, yielding increased performance. This article...

Resumen Este artículo compara empírica y teóricamente varias optimizaciones de estimación de densidades en el plano tangente, que es una técnica para ilumi-nación global. Esta técnica se basa en Photon Maps y da más exactitud si las superficies no son local-mente suaves o continuas. La primera de las op-timizaciones crea un conjunto de rayos candid...

Density estimation on the tangent plane (DETP) is a density estimation technique for global illumination. This technique is based on Photon Maps and provides increased accuracy when the surfaces are not locally smooth or continuous. However, the performance of the technique is limited by the large number of ray-disc intersections needed. Some optim...

This paper describes an approach to obtain interactive recalculation of global illumination for scenes with small moving objects (with respect to the complete geometry), on a standard PC, using density estimation techniques

We present a spatial representation based on a hierarchical structure using the well-known technique of octree as spatial indexing. There are very useful spatial representations for scenes whose objects can be distributed in clusters. Our proposed spatial representation is quite interesting for scenes that satisfy the previous objects distribution....

Java performance has been increasing steadily for the past few years, and can now compete with that of C and Fortran. This paper describes the porting of Ludwig, which is a versatile code for the simulation of Lattice-Boltzmann models in 3D on cubic lattices, to Java in order to increase its portability. The performance difference between the origi...