Fusion Plasma simulation in the Interactive Grid

Within the framework of the int.eu.grid project, IVISDEP, which stands for Interactive Visualizer of an Integrator of Stochastic Differential Equations for Plasmas, has been successfully ported and executed. It is an example of integration of many of the innovative features that this grid infrastructure offers. The application itself simulates and visualizes the evolution of the plasma inside a stellarator fusion device. The followed approach implies the simulation of a great number of trajectories of particles, whose positions are calculated among a large number of nodes in the Grid. The graphical interface allows the user to see and modify the physical and computational parameters of the simulation interactively, making this application a valuable tool for researchers in plasma physics

Graphical Framework for Grid Interactive and Parallel Applications

Considering how complex Grid technology is, it is essential to provide adequate support on users' level in order to simplify interaction and attract users. Intuitive and easy-to-use graphical user interfaces could be critical for the usefulness of the whole infrastructure and may play a significant role within successful stories. We would like to present the int.eu.grid approach to a Migrating Desktop product providing a unified and intuitive graphical work environment that allows users to control sophisticated interactive services, access Grid resources, run sequential and parallel jobs -- using both batch and interactive paradigms. The Migrating Desktop provides a front-end for embedding some of the application mechanisms and interfaces, and it allows the user to have virtual access to Grid resources. Generic API for applications based on the OSGi specification provides mechanisms for the job submission phase, interaction with an application and remote visualization of the results which assemble the powerful platform for the Grid environment

Interactive Techniques in Grid Computing: A Survey

In Grid computing, the dominating paradigm is batch processing. Grid middleware ships with batch-job support only, while lacking support for interactive applications. The reason is that grid middleware was developed for computation-intensive jobs, which may run for a long time before a result becomes available. This leads to a ``post-mortem'' approach of analysing the output, possibly resulting in a waste of computing and research time. Adding the possibility to observe and steer the job during execution enables the researcher to modify job-parameters without restarting the entire job. In this paper, several interactivity support techniques are explored, followed by several examples proving their usefulness

Methods and Distributed Software for Visualization of Cracks Propagating in Discrete Particle Systems

Scientific visualization is becoming increasingly important in analyzing and interpreting numerical and experimental data sets. Parallel computations of discrete particle systems lead to large data sets that can be produced, stored and visualized on distributed IT infrastructures. However, this leads to very complicated environments handling complex simulation and interactive visualization on the remote heterogeneous architectures. In micro-structure of continuum, broken connections between neighbouring particles can form complex cracks of unknown geometrical shape. The complex disjoint surfaces of cracks with holes and unavailability of a suitable scalar field defining the crack surfaces limit the application of the common surface extraction methods. The main visualization task is to extract the surfaces of cracks according to the connectivity of the broken connections and the geometry of the neighbouring particles. The research aims at enhancing the visualization methods of discrete particle systems and increasing speed of distributed visualization software. The dissertation consists of introduction, three main chapters and general conclusions. In the first Chapter, a literature review on visualization software, distributed environments, discrete element simulation of particle systems and crack visualization methods is presented. In the second Chapter, novel visualization methods were proposed for extraction of crack surfaces from monodispersed particle systems modelled by the discrete element method. The cell cut-based method, the Voronoi-based method and cell centre-based method explicitly define geometry of propagating cracks in fractured regions. The proposed visualization methods were implemented in the grid visualization e–service VizLitG and the distributed visualization software VisPartDEM. Partial data set transfer from the grid storage element was developed to reduce the data transfer and visualization time. In the third Chapter, the results of experimental research are presented. The performance of e-service VizLitG was evaluated in a geographically distributed grid. Different types of software were employed for data transfer in order to present the quantitative comparison. The performance of the developed visualization methods was investigated. The quantitative comparison of the execution time of local Voronoi-based method and that of global Voronoi diagrams generated by Voro++ library was presented. The accuracy of the developed methods was evaluated by computing the total depth of cuts made in particles by the extracted crack surfaces. The present research confirmed that the proposed visualization methods and the developed distributed software were capable of visualizing crack propagation modelled by the discrete element method in monodispersed particulate media