A semantically-enhanced grid registry: Work in progress Sylvia - - PowerPoint PPT Presentation
A semantically-enhanced grid registry: Work in progress Sylvia Wong, Victor Tan, Weijian Fang, Simon Miles, Luc Moreau School Electronics and Computer Science University of Southampton, UK 1 www.grimoires.org Grimoires Grid Registry Project
School Electronics and Computer Science University of Southampton, UK
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⋄ Grid RegIstry with Metadata Oriented Interface: Robust-
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⋄ Large number of services advertised
⋄ Filter out most suitable services ⋄ Augment
⋄ Service providers ⊲ Access polices, contract negotiation details ⋄ Users ⊲ Quality of service, reputation metrics
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⋄ Services ⋄ Operations supported by services ⋄ Input and output types of operations
⋄ Users to enrich descriptions not foreseen by providers
⋄ Some metadata can change frequently, eg user ratings ⋄ Can be updated without republishing the entity or other
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⋄ Subject: entity to be annotated ⋄ Predicate: type of annotation ⋄ Object: value of annotation ⊲ string, URI or RDF graph ⋄ Examples ⊲ (service, mygrid:NumericRating, 8.5) ⊲ (input, mygrid:SemanticType, mygrid:Nucleotide Sequence)
⋄ date, author
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⋄ List of all metadata attached to a service ⋄ List of all entities with metadata that match a list ⋄ RDQL (RDF query language) ⊲ For query patterns not exposed in inquiry interface ⊲ Example: Metadata data values are exact matches currently, use
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⋄ Tomcat, Apache Axis, Globus Toolkit 4, OMII
⋄ In-memory: Faster, enough for 1 million services ⋄ PostgreSQL, MySQL, Berkeley DB
interface UDDIv2 metadata interface sation module authori− triple Jena store UDDI compliant client Grimoires client uddi4j, etc Registry
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⋄ Username/password credential scheme ⋄ Authentication tokens
⋄ Eg, Globus, OMII
⋄ WS-Security standards compliant SOAP message signing
⋄ Authentication using Distinguished Name (DN) extracted
⋄ Benefits ⊲ Easy integration into existing Grid security infrastructure ⊲ First step to single sign-on
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⋄ Identify problem areas in efficiency and scalability ⋄ Service publication and inquiry ⋄ Metadata inquiry
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0.1 1 10 100 1000 5000 10000 15000 20000 25000 Time (second) Number of services Publishing 100 Services against Registry Data Size GRIMOIRES, WS GRIMOIRES, BL jUDDI 0.9rc4
⋄ Average publication time: 30ms per service
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0.1 1 10 100 5000 10000 15000 20000 25000 Time (second) Number of services Inquiring 100 Services against Registry Data Size GRIMOIRES, WS GRIMOIRES, BL jUDDI 0.9rc4 Inquiry-By-Metadata
⋄ Average inquiry time: 100ms per service
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⋄ Ontology aware service discovery
⋄ Third-party publication leads to more complicated access
⊲ Who can annotate a service? ⊲ Who can update a piece of metadata? ⊲ Querying only a subset of metadata?
⋄ Different triple store implementations ⋄ Distributed registry
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⋄ Metadata interface ⋄ Signature based authentication ⋄ Preliminary performance tests ⋄ Future work
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