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Pierson, Jean‐Marc; Brunie, Lionel
doi: 10.1002/cpe.1184pmid: N/A
The successful adaptation of information integration techniques to the requirements of data Grids is essential for the proliferation of Grid technology. In addition to the well‐known problems encountered when integrating heterogeneous sources, the dynamic Grid environment introduces new challenges. This paper discusses the problem of data source discovery, i.e. the selection of the most useful data sources for a given information demand out of a possibly very large set of candidates. We introduce the concept of data source utility and emphasize the pivotal role of semantic correspondences or schema matches for utility. Different variants of concrete utility measures used in an advanced Grid data source registry are presented. Copyright © 2007 John Wiley & Sons, Ltd.
Pierson, Jean‐Marc; Brunie, Lionel
doi: 10.1002/cpe.1185pmid: N/A
Network‐enabled server (NES) environments are valuable candidates to provide simple computing Grid access. These environments allow transparent access to a set of computational servers via Remote Procedure Call mechanisms. In this context, a challenge is to increase performances by decreasing data traffic. This paper presents DTM (Data Tree Manager), a data management service for NES environments. Based on the notions of data persistency and data replication, DTM proposes a set of efficient policies which minimize computation times by decreasing data transfers between the clients and the platform. From the end‐user point of view, DTM is accessible through a simple and transparent API. We describe DTM and its implementation in the DIET (Distributed Interactive Engineering Toolbox) platform. We also present a set of experimental results which show the feasibility and the efficiency of our approach. Copyright © 2007 John Wiley & Sons, Ltd.
Pierson, Jean‐Marc; Brunie, Lionel
doi: 10.1002/cpe.1212pmid: N/A
Distributed systems like grids support diverse models of distributed computation and need to operate large data entities in a distributed way. A significant quantity of this data are used only for a limited period of time. Caching is recognized as one of the most effective techniques to manage temporary data and collaborative cache is traditionally proposed to scale cache capabilities in distributed environments. Grid needs to manage dynamically different models of computation with different data access patterns. In this paper, we propose a basic infrastructure for the management of collaborative caches that permits to operate and control dynamically different cache mechanisms and cache schemes in grid. Beside traditional collaborative caching where the cooperation is often limited to data resolution, in our infrastructure the collaborative cache capacities are extended to operate and manage these distributed temporal data. Our proposition is composed of a reference cache model that defines four layers for the management of collaborative cache; an information model that represents the main cache elements and their activity; and a set of operations to request specific tasks to monitor, operate, and coordinate a generic collaborative cache system. Implementation issues of a prototype in Globus Toolkit 4 are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Pierson, Jean‐Marc; Brunie, Lionel
doi: 10.1002/cpe.1192pmid: N/A
The solar‐terrestrial physics distributed database for the ICSU World Data Centers, and the NCEP/NCAR climate re‐analysis data have been integrated into standard Grid environments using the OGSA‐DAI framework. A set of algorithms and software tools for distributed querying and mining environmental archives using the UNIDATA Common Data Model concepts has been developed. In addition, the toolkit enables querying the data using meaningful ‘human linguistic’ terms. Copyright © 2007 John Wiley & Sons, Ltd.
Pierson, Jean‐Marc; Brunie, Lionel
doi: 10.1002/cpe.1165pmid: N/A
In this paper we describe our work on enabling dynamic access control and secure management over federated data resources, such as relational or XML databases exposed to public network infrastructures via OGSA‐DAI middleware. We have proposed some extensions to the OGSA‐DAI architecture and successfully implemented new mechanisms enabling secure communication and distributed data integrity along with fine‐grain authorization and policy enforcement to minimize the complexity of the security right management. As a proof of concept some preliminary results of various performance tests of our solutions are also presented in this paper. We then analyze our achievements and describe future work and research. Copyright © 2007 John Wiley & Sons, Ltd.
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