OWL-S: As a Semantic Mark-up Language for Grid Services By Narendranadh.J

Topics ObjectiveIntroduction Current Scenario MotivationSemantics OWL-S Relevance to Grid Services Previous Work Why GWSDL2OWL-S How To Migrate From GWSDL2OWL-S Solution Space/Implementation What needs to be done/Challenges Conclusions Future Work

Objective To propose a suitable semantic description language for grid services

Introduction What is a Grid Service: Any Physical or logical resource Any Physical or logical resource e.g.: A collection of computers or A Complex Software Program e.g.: A collection of computers or A Complex Software Program What is a Semantic Description Language: Represents resources in terms of their “meaning” rather than “syntax”. Represents resources in terms of their “meaning” rather than “syntax”. e.g.: A UNIX machine is either Solaris, LINUX etc. e.g.: A UNIX machine is either Solaris, LINUX etc.

Current Scenario Grid Services are Represented Syntactically.[ OGSI Spec.] Uses GWSDL – Extension of WSDL Uses GWSDL – Extension of WSDL The Extensions are for: The Extensions are for: State Fullness [ Service Data] State Fullness [ Service Data] Service Description Service Description Life Cycle Management Life Cycle Management

Motivation According to OGSI: The service description is meant to capture both interface syntax, as well as (in a very rudimentary, non-normative fashion) semantics. The service description is meant to capture both interface syntax, as well as (in a very rudimentary, non-normative fashion) semantics. Concise semantics can be associated with each of these names in specification documents—and perhaps in the future through Semantic Web or other more formal descriptions. Concise semantics can be associated with each of these names in specification documents—and perhaps in the future through Semantic Web or other more formal descriptions.

Motivation (cont’d) Semantic Grid Visions for an e-science environment Visions for an e-science environment Demands: Demands: Dynamic Info. Dynamic Info. QoS of Grid services QoS of Grid services Versioning and Dynamic Policy Changes Versioning and Dynamic Policy Changes Multi Party Negotiation Multi Party Negotiation Interoperability Interoperability Also, Demands a More Expressive Language for Grid Service Publishing, Discovery and Composition.

Semantics OWL-S: Ontology Web Language for Web Services Claims: Claims: 1) Automatic Web Service Discovery 1) Automatic Web Service Discovery 2) Automatic Web Service Invocation 2) Automatic Web Service Invocation 3) Automatic Web Service Composition and Interaction 3) Automatic Web Service Composition and Interaction 4) Automatic Web Service Execution Monitoring [ Currently not Supported] 4) Automatic Web Service Execution Monitoring [ Currently not Supported]

Semantics [ cont’d] OWL-S uses OWL classes to represent resources, properties and the relationships between different classes OWL reasoners infer semantics from these properties and relationships OWL-S include: Service Profile: service desc. for humans Service Profile: service desc. for humans Service Model: IOPEs Service Model: IOPEs Service Grounding: Concrete Specification Service Grounding: Concrete Specification

OWL-S Relevance to Grid Services Service Profiles Can be Used in Dual Ways: Representing Service Capabilities Representing Service Capabilities Representing Service Needs Representing Service Needs Service Model Allows: Resource Analysis, Service Composition, Coordination and Execution Monitoring Resource Analysis, Service Composition, Coordination and Execution Monitoring

Previous Work G-QoSM: Grid Service Discovery Using QoS Properties, Rashid etal Ontology-based Resource Matching in the Grid – The Grid meets the Semantic Web Hongsuda Tangmunarunkit etal A Grid Service Discovery Matchmaker based on Ontology Description, Simone A. Ludwig etc. Autonomic Service Adaptation in ICENI using Ontological Annotation, Jeffrey Hau etal.

Why GWSDL2OWL-S GWSDL is Based on WSDL, Which is Syntactic Representation of Web Services Will Revolutionize Grid Resource Utilization by Introducing Semantics in GWSDL Extensions Like: Service Data, Service Description, Life Cycle Management, Fault Management and Change Management Service Data, Service Description, Life Cycle Management, Fault Management and Change Management

How to Migrate from GWSDL2OWL-S Both Use Abstract Types and Concrete Types GWSDL Abstract Types Concrete Types OWL-S Abstract Types Concrete Types GWSDL2OWL-S

Cont’d GWSDL Uses Semantically Poor WSDL XSD Types to Represent Abstract Types and Has a Good Grounding Specification OWL-S Uses Semantically Rich OWL-S Classes and Is Not Yet Well Defined In Service Grounding So, The Reference Architecture Will Include OWL Abstract Types and WSDL/GWSDL Concrete Types

Solution Space/Implementation Globus Resource Management Architecture [ Using OWL-S ] Application LSF GRAM Condor GRAM NQE GRAM Co-allocator Brokers Info. Service OWL-S Queries & Info Ground OWL-S WSDL/GWSDL

Challenges Defining Name Spaces for GWSDL to OWL-S OWL-S Editor for Grid Consumers Tool for Automatic Transformation From GWSDL2OWL-S

Conclusions Semantic Grid Requires An Expressive Language For Grid Services and OWL-S Suitably Fits Into The Requirement But, To Be Effective OWL-S Must Be Supported By Domain Ontology

Future Work Defining Example Grid Service Using OWL-S and GWSDL Developing GWSDL2OWL-S Tool Kit