1. FP6-511513 OntoGrid: Paving the way for Knowledgeable Grid Services and Systems www.ontogrid.net Sheffield, 21st February 2006 Semantic-OGSA A Reference Architecture for the Semantic Grid Oscar Corcho The University of Manchester

2. 2S-OGSA Content  What is the Grid and the Semantic Grid?  S-OGSA  Authorisation scenario  General architecture  Collaboration diagrams  Use of S-OGSA OntoGrid-specific infrastructure  VO ontology and reasoning service  Ontology service: WS-DAIOnt-RDF(S)  Metadata service: Atlas  Project details: URLs, CVS, etc.

3. 3S-OGSA The Grid Grid computing has emerged as an important new field, distinguished from conventional distributed computing by its focus on large-scale resource sharing, innovative applications...we [define] the "Grid problem”…as flexible, secure, coordinated resource sharing among dynamic collections of individuals, institutions, and resources - what we refer to as virtual organizations Middleware for establishing, managing and evolving multi-organisational federations. On-demand distributed computing The Anatomy of the Grid: Enabling Scalable Virtual Organizations Foster, Kesselman and Tuecke

4. 4S-OGSA Grid Computing trajectory CPU scavenging CPU intensive workload Grid as a utility, data Grids, robust infrastructure Intra-company, intra community e.g. Life Science Grid Sharing standard scientific process and data, sharing of common infrastructure Between trusted partners Sharing of apps and know-how With controlled set of unknown clients Virtual organisations with dynamic access to unlimited resources For all time cost The Semantic Grid: Myth Busting and Bridge Building Carole Goble. Keynote speech. ECAI04.

5. 5S-OGSA Computationally intensive File access/transfer Bag of various heterogeneous protocols & toolkits Monolithic design Recognised internet, ignored Web Academic teams Generation Game Increased functionality, standardization Time Custom solutions Open Grid Services Architecture Web services Globus Toolkit Condor, Unicore Defacto standards GridFTP, GSI X.509, LDAP, FTP, … App-specific Services Data and knowledge intensive Open services-based architecture Builds on Web services GGF + OASIS + W3C Multiple implementations Global Grid Forum Industry participation (adapted from Ian Foster GGF7 Plenary)

6. 6S-OGSA Open Grid Service Architecture  Categories of Services  Infrastructure  Data  Resource Management  Execution Management  Security  Self Management  Information  Cross cutting  Interoperable  VO level  Optimized  Reliable  Certain QoS Guarantee  Scalable  Available  Extensible  XML based vocabularies & XSD based typing dominate

7. 7S-OGSA Grid Services  References  “The Physiology of the Grid: An Open Grid Service Architecture for Distributed Systems Integration”  “The Anatomy of the Grid: Enabling Scalable Virtual Organizations”  Grid Service definition  A Web service that provides a set of well-defined interfaces and that follows specific conventions. Interfaces: discovery, dynamic service creation, lifetime management, notification, and manageability Conventions: naming and upgradeability.

8. 8S-OGSA From OGSI to WSRF  OGSI (Open Grid Service Interface) fomalised these concepts...  Grid service instances identified by Grid service handlers (GSH) A permanent network pointer to a Grid service instance.  Grid service references (GSR) used to contact Grid service instances  OGSI provides mechanisms for mapping a GSH to a GSR.  However, OGSI did not succeed  Too much stuff in one specification.  Does not work well with existing Web service and XML tooling.  Too object oriented.  Since January 2004, WS-RF (Web Service Resource Framework)  It is simply a re-factoring of OGSI. Inheritance is not used. WS-Resources instead of Grid service instances.

9. 9S-OGSA Web Service WS-Resource Counter Client createResource Counter Resourc e counterID=1 Counter Resource counterID=2 add WS-Addressing EPR add Destroy

10. 10S-OGSA Open Grid Service Architecture  Categories of Services  Infrastructure  Data  Resource Management  Execution Management  Security  Self Management  Information  What can semantics provide?  Flexible and extensible schemas, Data fusion support (e.g. Provided by RDF)  Resistance to frequent syntactic changes  Formalization & Reasoning support  Eliminate chronic dependence on human- intervention  Cross cutting  Interoperable  VO level  Optimized  Reliable  Certain QoS Guarantee  Scalable  Available  Extensible  XML based vocabularies & XSD based typing dominate

11. 11S-OGSA The Semantic Grid is an extension of the current Grid in which information and services are given well-defined and explicitly represented meaning, better enabling computers and people to work in cooperation Research Agenda for the Semantic Grid: a Future e-Science Infrastructure D. De Roure, N.R. Jennings, N. Shadbolt The Semantic Grid Scale of data and computation Scale of Interoperability Semantic Web Classical Web Semantic Grid Classical Grid

12. 12S-OGSA Service Oriented Knowledge Utilities  Converged vision of Next Generation Grids and Service Oriented Knowledge Utilities  Service Oriented –services may be instantiated and assembled dynamically  Knowledge –knowledge-assisted to facilitate automation, and processing and delivering knowledge  Utility –directly and immediately useable service with established functionality, performance and dependability Ecosystem of Dependable, Knowledge-aware, Societal, Autonomic, Stateful services Next Generation Grids Expert Group Report 3 (NGG3). January 2006 D. De Roure (ed)

13. 13S-OGSA Content  What is the Grid and the Semantic Grid?  S-OGSA  Authorisation scenario  General architecture  Collaboration diagrams  Use of S-OGSA OntoGrid-specific infrastructure  VO ontology and reasoning service  Ontology service: WS-DAIOnt-RDF(S)  Metadata service: Atlas  Project details: URLs, CVS, etc.

14. 14S-OGSA Desiderata – a thing of elegance and beauty Architecture as lightweight as possible: minimise the impact Extensible and customisable as opposed to complete and generic architecture Everything is OGSA compliant Mixed ecosystem of Grid and Semantic Grid services Straightforward migration path Any resource can have multiple descriptions and any description can be in different formalisms Conceptual: reference architecture that can be applied to any grounding (GT4, etc.)

15. 15S-OGSA  Semantic-OGSA (S-OGSA) is...  Our proposed Semantic Grid reference architecture  A low-impact extension of OGSA Mixed ecosystem of Grid and Semantic Grid services  Services ignorant of semantics  Services aware of semantics but unable to process them  Services aware of semantics and able to process (part of) them Everything is OGSA compliant  Defined by Information model Capabilites Mechanisms Model Capabilities Mechanisms provide/ consume expose use

16. 16S-OGSA S-OGSA Model and Capabilities

17. 17S-OGSA METADATA as Semantic Annotations

18. 18S-OGSA Optimization Execution Management Resource management Data Security Information Management Infrastructure Services Application 1Application N OGSA Semantic-OGSA Semantic Services From OGSA to the S-OGSA

19. 19S-OGSA Optimization Execution Management Resource management Data Security Information Management Infrastructure Services Application 1Application N OGSA Semantic-OGSA Semantic Services From OGSA to the S-OGSA Ontology Reasoning Knowledge Metadata Annotation Semantic binding Semantic Provisioning Services

20. 20S-OGSA S-OGSA Mechanisms: S-StatefulServices Lifetime Notification State/properties metadata... WSRF defined operations getProperties queryProperties Service Resource Client 3 1 2 Semantic Binding Ids Retrieval Request Semantic Binding Ids Metadata Retrieval/Query Request 4 Query/Retrieval Result 5 Obtain schema for Semantic Bindings Metadata Service Metadata Service Ontology Service Ontology Service Metadata can be distributed (and may be inconsistent)

21. 21S-OGSA OntoKit: Refactored and additional components Coordination and negotiation Intelligent Debugging Coordination and negotiation Intelligent Debugging Semantically Aware

22. 22S-OGSA Content  What is the Grid and the Semantic Grid?  S-OGSA  Authorisation scenario  General architecture  Collaboration diagrams  Use of S-OGSA OntoGrid-specific infrastructure  VO ontology and reasoning service  Ontology service: WS-DAIOnt-RDF(S)  Metadata service: Atlas  Project details: URLs, CVS, etc.

23. 23S-OGSA getInsurancePolicy Driver John Doe Business scenario – supporting the authorization model InterInsurance Portal BestInsurer Portal getInsurancePolicy DENY ACCEPT INDETERMINATE OntoKit Infrastructure for authorisation InterInsurance CarFraudService (PEP) Common objective: improve operations and prevent frauds Partial sharing of customer information (previous insurance details, claims, etc.) Result or Exception Insurance DB federation getInsurancePolicy DENY ACCEPT INDETERMINATE OntoKit Infrastructure for authorisation BestInsurer CarFraudService (PEP) Result or Exception Insurance DB federation … …

24. 24S-OGSA InterInsurance CarFraudService (PEP) getInsurancePolicy Driver John Doe Policy Enforcement Point (according to GT4) InterInsurance Portal BestInsurer Portal getInsurancePolicy DENY ACCEPT INDETERMINATE OntoKit Infrastructure for authorisation InterInsurance CarFraudService (PEP) Partial sharing of customer information (previous insurance details, claims, etc.) Result or Exception Insurance DB federation getInsurancePolicy DENY ACCEPT INDETERMINATE OntoKit Infrastructure for authorisation BestInsurer CarFraudService (PEP) Result or Exception Insurance DB federation … …

25. 25S-OGSA InterInsurance CarFraudService (PEP) getInsurancePolicy Driver John Doe Policy Decision Point (OntoKit infrastructure) InterInsurance Portal BestInsurer Portal getInsurancePolicy DENY ACCEPT INDETERMINATE OntoKit Infrastructure for authorisation Partial sharing of customer information (previous insurance details, claims, etc.) Result or Exception Insurance DB federation getInsurancePolicy DENY ACCEPT INDETERMINATE OntoKit Infrastructure for authorisation BestInsurer CarFraudService (PEP) Result or Exception Insurance DB federation … …

26. 26S-OGSA WS-DAIOnt XACML_AuthZService (PDP) CarFraudService (PEP) XACML AuthZ Request getInsurancePolicy VO Ontology Class Hierarchy -RDFS RD F John Doe has had 2 distinct accidents Role Op Mapping Pellet Reasoner Obtain Semantic Bindings of John Doe Obtain all classes that are subclass of ROLE Classify John Doe wrt VO ont Lookup whether the ROLE that is inferred permits or not XACML AuthZ Response 1 2 3 4 5 6 7 Atlas PIP Proxy PDP Proxy VO Ontology OWL Demonstrator. Collaboration Diagram 8 Result or Exception

27. 27S-OGSA WS-DAIOnt XACML_AuthZService (PDP) CarFraudService (PEP) XACML AuthZ Request getInsurancePolicy VO Ontology Class Hierarchy -RDFS RD F John Doe has had 2 distinct accidents Role Op Mapping Pellet Reasoner Obtain Semantic Bindings of John Doe Obtain all classes that are subclass of ROLE Classify John Doe wrt VO ont Lookup whether the ROLE that is inferred permits or not XACML AuthZ Response 1 2 3 4 5 6 7 Atlas PIP Proxy PDP Proxy VO Ontology OWL Demonstrator. Collaboration Diagram 8 Result or Exception Ignorant of semantics Semantic aware but unable to process semantics Semantic aware and able to process semantics

28. 28S-OGSA WS-DAIOnt XACML_AuthZService (PDP) CarFraudService (PEP) XACML AuthZ Request getInsurancePolicy VO Ontology Class Hierarchy -RDFS RD F John Doe has had 2 distinct accidents Role Op Mapping Pellet Reasoner Obtain Semantic Bindings of John Doe Obtain all classes that are subclass of ROLE Classify John Doe wrt VO ont Lookup whether the ROLE that is inferred permits or not XACML AuthZ Response 1 2 3 4 5 6 7 Atlas PIP Proxy PDP Proxy VO Ontology OWL Demonstrator. Collaboration Diagram 8 Result or Exception /C=GB/O=PERMIS/CN=User0

29. 29S-OGSA WS-DAIOnt XACML_AuthZService (PDP) CarFraudService (PEP) XACML AuthZ Request getInsurancePolicy VO Ontology Class Hierarchy -RDFS RD F John Doe has had 2 distinct accidents Role Op Mapping Pellet Reasoner Obtain Semantic Bindings of John Doe Obtain all classes that are subclass of ROLE Classify John Doe wrt VO ont Lookup whether the ROLE that is inferred permits or not XACML AuthZ Response 1 2 3 4 5 6 7 Atlas PIP Proxy PDP Proxy VO Ontology OWL Demonstrator. Collaboration Diagram 8 Result or Exception

30. 30S-OGSA WS-DAIOnt XACML_AuthZService (PDP) CarFraudService (PEP) XACML AuthZ Request getInsurancePolicy VO Ontology Class Hierarchy -RDFS RD F John Doe has had 2 distinct accidents Role Op Mapping Pellet Reasoner Obtain Semantic Bindings of John Doe Obtain all classes that are subclass of ROLE Classify John Doe wrt VO ont Lookup whether the ROLE that is inferred permits or not XACML AuthZ Response 1 2 3 4 5 6 7 Atlas PIP Proxy PDP Proxy VO Ontology OWL Demonstrator. Collaboration Diagram 8 Result or Exception...

31. 31S-OGSA WS-DAIOnt XACML_AuthZService (PDP) CarFraudService (PEP) XACML AuthZ Request getInsurancePolicy VO Ontology Class Hierarchy -RDFS RD F John Doe has had 2 distinct accidents Role Op Mapping Pellet Reasoner Obtain Semantic Bindings of John Doe Obtain all classes that are subclass of ROLE Classify John Doe wrt VO ont Lookup whether the ROLE that is inferred permits or not XACML AuthZ Response 1 2 3 4 5 6 7 Atlas PIP Proxy PDP Proxy VO Ontology OWL Demonstrator. Collaboration Diagram 8 Result or Exception

32. 32S-OGSA WS-DAIOnt XACML_AuthZService (PDP) CarFraudService (PEP) XACML AuthZ Request getInsurancePolicy VO Ontology Class Hierarchy -RDFS RD F John Doe has had 2 distinct accidents Role Op Mapping Pellet Reasoner Obtain Semantic Bindings of John Doe Obtain all classes that are subclass of ROLE Classify John Doe wrt VO ont Lookup whether the ROLE that is inferred permits or not XACML AuthZ Response 1 2 3 4 5 6 7 Atlas PIP Proxy PDP Proxy VO Ontology OWL Demonstrator. Collaboration Diagram 8 Result or Exception...

33. 33S-OGSA Content  What is the Grid and the Semantic Grid?  S-OGSA  Authorisation scenario  General architecture  Collaboration diagram  Use of S-OGSA OntoGrid-specific infrastructure  VO ontology and reasoning service  Ontology service: WS-DAIOnt-RDF(S)  Metadata service: Atlas  Project details: URLs, CVS, etc.

34. 34S-OGSA WS-DAIOnt XACML_AuthZService (PDP) CarFraudService (PEP) XACML AuthZ Request getInsurancePolicy VO Ontology Class Hierarchy -RDFS RD F John Doe has had 2 distinct accidents Role Op Mapping Pellet Reasoner Obtain Semantic Bindings of John Doe Obtain all classes that are subclass of ROLE Classify John Doe wrt VO ont Lookup whether the ROLE that is inferred permits or not XACML AuthZ Response 1 2 3 4 5 6 7 Atlas PIP Proxy PDP Proxy VO Ontology OWL The VO ontology and the reasoning service. Configuration Configurable pieces 8 Result or Exception

35. 35S-OGSA The VO ontology and the reasoning service (I)  VO ontology b ased on... KaOS ontologies (Actors, Groups and Actions) UNICORE ontology (Entities, Identities and Roles)  Joint development between NextGrid, UniGrids and OntoGrid  Policy definition  Role-based Actors or groups of actors have a set of roles in the VO Tasks:  Extend ontology with domain-specific classes and properties  Define roles wrt these extensions  E.g., a blacklistedDriver is a driver that has had at least 3 accident claims in the past  E.g., a goodReputationDriver is a driver that has been insured at least by one trusted company and that has had at most 2 accident claims PDP uses a DL classifier to obtain roles of a subject  Mapping roles-operations Available in a lookup table

36. 36S-OGSA The VO ontology and the reasoning service (II)

37. 37S-OGSA S-OGSA Model and Capabilities (reminder) Semantic Provisioning Service Knowledge Resource Grid Entity Semantic Binding Grid Service Is-a 0.. m 1.. m Semantic aware Grid Service consumeproduce 0.. m 1.. m uses VOMS SAML DFDL file JSDL file Is-a Knowledge Entity Is-a Ontology Service Is-a Reasoning Service Semantic Binding Provisioning Service Annotation Service Metadata Service Grid Resource IDT Atlas Is-a Knowledge Provisioning Service Is-a Ontology Rule set Knowledge Semantic Grid Grid

38. 38S-OGSA Ontology services  Adapt and extend ontology services to be Grid compliant  Access heterogeneus and distributed ontology sources as a homogeneous logical resources  Provide homogeneous service interfaces  Modular design to ease extensibility WS-DAI Message Patterns Behavioural Properties WS-DAIOntWS-DAIX XML WS-DAIR Relational WS-DAIOnt-RDF RDF Specific WS-DAIOnt-OWL OWL specific WS-RDF JenaSesame

39. 39S-OGSA RDFS model

40. 40S-OGSA Component Description Jena....

41. 41S-OGSA S-OGSA Model and Capabilities (reminder) Semantic Provisioning Service Knowledge Resource Grid Entity Semantic Binding Grid Service Is-a 0.. m 1.. m Semantic aware Grid Service consumeproduce 0.. m 1.. m uses VOMS SAML DFDL file JSDL file Is-a Knowledge Entity Is-a Ontology Service Is-a Reasoning Service Semantic Binding Provisioning Service Annotation Service Metadata Service Grid Resource IDT Atlas Is-a Knowledge Provisioning Service Is-a Ontology Rule set Knowledge Semantic Grid Grid

42. 42S-OGSA Atlas  Atlas is a P2P system for the distributed storage and querying of RDF(S) data using DHTs.  State of implementation  Base technology: Bamboo DHT (http://bamboo-dht.org)  Model: RDF (eventually RDFS as well)  Query and update languages: RQL (subset of data queries) and RUL (not yet implemented)  Functionality: one-time queries (implemented), publish/subscribe (under development).

43. 43S-OGSA Atlas and the Metadata Service ATLAS METADATA SERVICE INTERFACE I want to publish information about a resource I want to discover a resource that meets my needs METADATA SERVICE INTERFACE Web service protocols Web service protocols

44. 44S-OGSA Content  What is the Grid and the Semantic Grid?  S-OGSA  Authorisation scenario  General architecture  Collaboration diagram  Use of S-OGSA OntoGrid-specific infrastructure  VO ontology and reasoning service  Ontology service: WS-DAIOnt-RDF(S)  Metadata service: Atlas  Project details: URLs, CVS, etc.

45. 45S-OGSA Project details  OntoGrid  Publications at http://www.ontogrid.net/ CTWatch Journal of Web Semantics (Special issue on Semantic Grid) GGF16 Semantic Grid Workshop (http://www.semanticgrid.org/)  Source code http://www.ontogrid.net/, Downloads  Not very user-friendly yet Access to CVS  Connection type: pserver  user: ontogrid  password: not needed  Host: rpc262.cs.man.ac.uk  Port: 2401  Repository path: /local/ontogrid/cvsroot  module: prototype

46. 46S-OGSA Acknowledgements  The OntoGrid team at Manchester  Pinar Alper, Ioannis Kotsiopoulos, Paolo Missier, Sean Bechoffer, Carole Goble  The OntoGrid team at other sites  UPM: WS-DAIOnt-RDF(S)  NKUA: Atlas  Others already acknowledged in the slides

47. 47S-OGSA More References  http://www.globus.org/wsrf  Modeling Stateful Resources with Web Services  The WS-Resource Framework  From Open Grid Services Infrastructure to WS-Resource Framework: Refactoring and Extension  WSRF OASIS working group  http://www.oasis- open.org/committees/tc_home.php?wg_abbrev=wsrf  WS-Notification OASIS working group  http://www.oasis- open.org/committees/tc_home.php?wg_abbrev=wsn

48. FP6-511513 OntoGrid: Paving the way for Knowledgeable Grid Services and Systems www.ontogrid.net Sheffield, 21st February 2006 Semantic-OGSA A Reference Architecture for the Semantic Grid Oscar Corcho The University of Manchester