1,721,107 research outputs found
An Agent-Based Coupling Platform for Complex Automata
Get PDFThe ability to couple distinct computational models of science and engineering systems is still a recurring challenge when developing multiphysics applications.The applied coupling technique is often dictated by various constraints (such as hard- and software requirements for the submodels to be coupled). This may lead to different coupling strategies/implementations in case a submodel has to be replaced in an existing coupled setup.Additional efforts are required when it comes to multiscale coupling. At least one of the submodels has to be modified to provide a matching interface on a specific spatial and temporal scale.In the present paper we describe a generic coupling mechanism/framework to reduce these common problems and to facilitate the development of multiscale simulations consisting of a multitude of submodels.The resulting implementation allows the coupling of legacy as well as dedicated codes with only minor adjustments. As the system is being build upon the JADE library, our platform fully supports computations on distributed heterogeneous hardware.We discuss the platform’s capabilities by demonstrating the coupling of several cellular-automata kernels to model a coupled transport problem
Computational Science – ICCS 2007:7th International Conference, Beijing, China, May 27 - 30, 2007 : proceedings
No full textA Tool for Building Collaborative Applications by Invocation of Grid Operations
No full textThe motivation for this work is the need for providing tools which facilitate building scientific applications that are developed and executed on various Grid systems, implemented with different technologies. As a solution to this problem, we have developed the Grid Operation Invoker (GOI) which offers object-oriented method invocation semantics for interacting with computational services accessible with diverse middleware frameworks. GOI forms the core of the ViroLab virtual laboratory engine and it is used to invoke operations from within experiments described using a scripting notation. In this paper, after outlining the features of GOI, we describe how it is enhanced with a mechanism of so-called local gems which allows adding high-level support for middleware technologies based on the batch job-processing model, e.g. EGEE LCG/gLite. As a result, we demonstrate how a molecular dynamics program called NAMD, deployed on EGEE, was integrated with the ViroLab virtual laboratory
Simulating N-body systems on the grid using dedicated hardware
No full textWe present performance measurements of direct gravitational N-body simulation on the grid, with and without specialized (GRAPE-6) hardware. Our intercontinental virtual organization consists of three sites, one in Tokyo, one in Philadelphia and one in Amsterdam. We run simulations with up to 196608 particles for a variety of topologies. In many cases, high performance simulations over the entire planet are dominated by network bandwidth rather than latency. Using a global grid of GRAPEs our calculation time remains dominated by communication over the entire range of N, which was limited due to the use of three sites. Increasing the number of particles will result in a more efficient execution and for N >= 2 · 10 to the power of 6 we expect the computation time to overtake the communication time. We compare our results with a performance model and find that our results are in accordance with the predicted values
Computational Science – ICCS 2007:7th International Conference, Beijing, China, May 27 - 30, 2007 : proceedings
No full textSecond Workshop on Teaching Computational Science WTCS 2008
No full textThe Second Workshop on Teaching Computational Science, within the International Conference on Computational Science, provides a platform for discussing innovations in teaching computational sciences at all levels and contexts of higher education. This editorial provides an introduction to the work presented during the sessions
Provenance Querying for End-Users: A Drug Resistance Case Study
No full textWe present a provenance model based on ontology representation of execution records of in silico experiments. The ontologies describe the execution of experiments, and the semantics of data and computations used during the execution. This model enables query construction in an end-user oriented manner, i.e. by using terms of the scientific domain familiar to researchers, instead of complex query languages. The presented approach is evaluated on a case study Drug Resistance Application exploited in the ViroLab virtual laboratory. We analyze the query capabilities of the presented provenance model. We also describe the process of ontology-based query construction and evaluation
Simulation of Multiphysics Multiscale Systems: Introduction to the ICCS’2007 Workshop
No full textModeling and simulation of multiphysics multiscale systems poses a grand challenge to computational science. To adequately simulate numerous intertwined processes characterized by different spatial and temporal scales (often spanning many orders of magnitude), sophisticated models and advanced computational techniques are required. The aim of the workshop on Simulation of Multiphysics Multiscale Systems (SMMS) is to facilitate the progress in this multidisciplinary research field. We provide an overview of the recent trends and latest developments, with special emphasis on the research projects selected for presentation at the SMMS’2007 workshop
Integrating and Accessing Medical Data Resources within the ViroLab Virtual Laboratory
No full textThis paper presents the data access solutions which have been developed in the ViroLab Virtual Laboratory infrastructure to enable medical researchers and practitioners to conduct experiments in the area of HIV treatment. Such experiments require access to a number of geographically distributed data sets (residing at various hospitals) with heavy focus on integration and security issues. Scientists conducting virtual experiments need to be able to manipulate such distributed data in a consistent and secure manner. We describe the main components of the Virtual Laboratory framework being devoted to data access and explain how data is processed in the presented environment
- …
