1,658 research outputs found
Querying Large Physics Data Sets Over an Information Grid
Optimising use of the Web (WWW) for LHC data analysis is a complex problem
and illustrates the challenges arising from the integration of and computation
across massive amounts of information distributed worldwide. Finding the right
piece of information can, at times, be extremely time-consuming, if not
impossible. So-called Grids have been proposed to facilitate LHC computing and
many groups have embarked on studies of data replication, data migration and
networking philosophies. Other aspects such as the role of 'middleware' for
Grids are emerging as requiring research. This paper positions the need for
appropriate middleware that enables users to resolve physics queries across
massive data sets. It identifies the role of meta-data for query resolution and
the importance of Information Grids for high-energy physics analysis rather
than just Computational or Data Grids. This paper identifies software that is
being implemented at CERN to enable the querying of very large collaborating
HEP data-sets, initially being employed for the construction of CMS detectors.Comment: 4 pages, 3 figure
Cosmological Simulations on a Grid of Computers
The work presented in this paper aims at restricting the input parameter
values of the semi-analytical model used in GALICS and MOMAF, so as to derive
which parameters influence the most the results, e.g., star formation, feedback
and halo recycling efficiencies, etc. Our approach is to proceed empirically:
we run lots of simulations and derive the correct ranges of values. The
computation time needed is so large, that we need to run on a grid of
computers. Hence, we model GALICS and MOMAF execution time and output files
size, and run the simulation using a grid middleware: DIET. All the complexity
of accessing resources, scheduling simulations and managing data is harnessed
by DIET and hidden behind a web portal accessible to the users.Comment: Accepted and Published in AIP Conference Proceedings 1241, 2010,
pages 816-82
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Leveraging legacy codes to distributed problem solving environments: A web service approach
This paper describes techniques used to leverage high performance legacy codes as CORBA components to a distributed problem solving environment. It first briefly introduces the software architecture adopted by the environment. Then it presents a CORBA oriented wrapper generator (COWG) which can be used to automatically wrap high performance legacy codes as CORBA components. Two legacy codes have been wrapped with COWG. One is an MPI-based molecular dynamic simulation (MDS) code, the other is a finite element based computational fluid dynamics (CFD) code for simulating incompressible Navier-Stokes flows. Performance comparisons between runs of the MDS CORBA component and the original MDS legacy code on a cluster of workstations and on a parallel computer are also presented. Wrapped as CORBA components, these legacy codes can be reused in a distributed computing environment. The first case shows that high performance can be maintained with the wrapped MDS component. The second case shows that a Web user can submit a task to the wrapped CFD component through a Web page without knowing the exact implementation of the component. In this way, a userâs desktop computing environment can be extended to a high performance computing environment using a cluster of workstations or a parallel computer
An Error Handling Framework for the ORBWork Workflow Enactment Service of METEOR
Workflow Management Systems (WFMSs) can be used to re-engineer, streamline, automate, and track organizational processes involving humans and automated information systems. However, the state-of-the-art in workflow technology suffers from a number of limitations that prevent it from being widely used in large-scale mission critical applications. Error handling is one such issue. What makes the task of error handling challenging is the need to deal with errors that appear in various components of a complex distributed application execution environment, including various WFMS components, workflow application tasks of different types, and the heterogeneous computing infrastructure.
In this paper, we discuss a top-down approach towards dealing with errors in the context of ORBWork, a CORBA-based fully distributed workflow enactment service for the METEOR2 WFMS. The paper discusses the types of errors that might occur including those involving the infrastructure of the enactment environment, system architecture of the workflow enactment service. In the context of the underlying workflow model for METEOR, we then present a three-level error model to provide a unified approach to specification, detection, and runtime recovery of errors in ORBWork. Implementation issues are also discussed. We expect the model and many of the techniques to be relevant and adaptable to other WFMS implementations
DIET : new developments and recent results
Among existing grid middleware approaches, one simple, powerful, and flexibleapproach consists of using servers available in different administrative domainsthrough the classic client-server or Remote Procedure Call (RPC) paradigm.Network Enabled Servers (NES) implement this model also called GridRPC.Clients submit computation requests to a scheduler whose goal is to find aserver available on the grid. The aim of this paper is to give an overview of anNES middleware developed in the GRAAL team called DIET and to describerecent developments. DIET (Distributed Interactive Engineering Toolbox) is ahierarchical set of components used for the development of applications basedon computational servers on the grid.Parmi les intergiciels de grilles existants, une approche simple, flexible et performante consiste a utiliser des serveurs disponibles dans des domaines administratifs diffĂ©rents Ă travers le paradigme classique de lâappel de procĂ©dure Ă distance (RPC). Les environnements de ce type, connus sous le terme de Network Enabled Servers, implĂ©mentent ce modĂšle appelĂ© GridRPC. Des clientssoumettent des requĂȘtes de calcul Ă un ordonnanceur dont le but consiste Ă trouver un serveur disponible sur la grille.Le but de cet article est de donner un tour dâhorizon dâun intergiciel dĂ©veloppĂ©dans le projet GRAAL appelĂ© DIET 1. DIET (Distributed Interactive Engineering Toolbox) est un ensemble hiĂ©rarchique de composants utilisĂ©s pour ledĂ©veloppement dâapplications basĂ©es sur des serveurs de calcul sur la grille
Forum Session at the First International Conference on Service Oriented Computing (ICSOC03)
The First International Conference on Service Oriented Computing (ICSOC) was held in Trento, December 15-18, 2003. The focus of the conference ---Service Oriented Computing (SOC)--- is the new emerging paradigm for distributed computing and e-business processing that has evolved from object-oriented and component computing to enable building agile networks of collaborating business applications distributed within and across organizational boundaries. Of the 181 papers submitted to the ICSOC conference, 10 were selected for the forum session which took place on December the 16th, 2003. The papers were chosen based on their technical quality, originality, relevance to SOC and for their nature of being best suited for a poster presentation or a demonstration. This technical report contains the 10 papers presented during the forum session at the ICSOC conference. In particular, the last two papers in the report ere submitted as industrial papers
CORBA-basierte Workflow-Architekturen : Die objektorientierte Kernanwendung der Bausparkasse Mainz AG
Bei der Initialisierung von Workflow-Projekten zur UnterstĂŒtzung von GeschĂ€ftsprozessen stellt sich die Frage, ob und warum ein Unternehmen angesichts der zahlreichen, auf dem Markt erhĂ€ltlichen Standardsysteme ein individuelles Workflow-System entwickeln sollte. Eine Reihe von Argumenten deutet darauf hin, daĂ individuelle Eigenentwicklungen durchaus eine erwĂ€genswerte Alternative zu den existierenden Standardsystemen darstellen. Aus der Diskussion dieses Aspektes ergibt sich u. a. die Frage, ob sich die Eigenentwicklung eines CORBA-konformen Workflow-Systems lohnt. Vielversprechende, bereits realisierte Systeme setzen auf die standardisierte, durchgĂ€ngig objektorientierte Architektur der Object Management Group (OMG). Deren Standard \u27CORBA\u27 (Common Object Request Broker) bietet zukunftsweisende technologische Vorteile (z. B. Verteiltheit, PlattformunabhĂ€ngigkeit, InteroperabilitĂ€t, ModularitĂ€t) und weist Synergieeffekte zum Workflow-Konzept auf. Die Bausparkasse Mainz AG (BKM) hat sich bereits 1996 fĂŒr die Eigenentwicklung eines CORBA-konformen Workflow-Systems entschieden; die neue Kernanwendung \u27BKM-Joker\u27 der BKM wird als AbschluĂ des vorliegenden Beitrages skizziert
Design Patterns for Description-Driven Systems
In data modelling, product information has most often been handled separately
from process information. The integration of product and process models in a
unified data model could provide the means by which information could be shared
across an enterprise throughout the system lifecycle from design through to
production. Recently attempts have been made to integrate these two separate
views of systems through identifying common data models. This paper relates
description-driven systems to multi-layer architectures and reveals where
existing design patterns facilitate the integration of product and process
models and where patterns are missing or where existing patterns require
enrichment for this integration. It reports on the construction of a so-called
description-driven system which integrates Product Data Management (PDM) and
Workflow Management (WfM) data models through a common meta-model.Comment: 14 pages, 13 figures. Presented at the 3rd Enterprise Distributed
Object Computing EDOC'99 conference. Mannheim, Germany. September 199
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