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Model-Based Workflows. Leonardo Salayandía University of Texas at El Paso. Overview. Context Cyberinfrastructure for scientific domains SOAs, service composition, and workflows A Domain-Specific Modeling approach The model: Workflow Driven Ontologies (WDOs)
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Model-Based Workflows Leonardo Salayandía University of Texas at El Paso DSM Workshop, October 22 OOPSLA 2006
Overview • Context • Cyberinfrastructure for scientific domains • SOAs, service composition, and workflows • A Domain-Specific Modeling approach • The model: Workflow Driven Ontologies (WDOs) • The DSL: Model-Based Workflows (MBWs) • Status DSM Workshop, October 22 OOPSLA 2006
Context • Cyberinfrastructure for the Geosciences (GEON) • Nation-wide NSF-funded project http://www.geongrid.org • Scientist collaborators • Creating ontologies to describe scientific domains • IT collaborators • Creating distributed resources across geosciences domains in the form of services (SOA) • Creating workflows to compose services into scientific applications • The DSM challenge • Bridging the gap between ontologies and workflow creation DSM Workshop, October 22 OOPSLA 2006
Ontologies • Scientists create the Domain Specific Model • OWL – Ontology Web Language (W3C) • Workflow Driven Ontologies (WDOs) • Define a context for scientists to create ontologies that are amenable to workflow generation • WDO creation software • Brainstorming phase to define information and method concepts • Relationship elicitation phase to define input/output relationships between information and methods concepts DSM Workshop, October 22 OOPSLA 2006
Workflows • IT professionals and scientists create workflows from services • Workflow languages not targeted for scientists • OWL-S (Semantic Web), MoML (Ptolemy II, Kepler) • Kepler Scientific Workflow Management System • Graphical abstraction of workflow language (MoML) • Closer to being used by scientists, but not there yet DSM Workshop, October 22 OOPSLA 2006
OWL-S example DSM Workshop, October 22 OOPSLA 2006
Kepler Workflow example DSM Workshop, October 22 OOPSLA 2006
Model Based Workflows • Contains terms defined by the scientist (not computer science terms) • Data types defined based on the scientist’s terms • Abstract level of specification • Not an executable DSL • Scientist can be sloppy about workflow specification, ex. partial orders • Scientists can understand the workflows, validate, and give feedback to the Workflow Driven Ontology DSM Workshop, October 22 OOPSLA 2006
Model Based Workflows • Simple constructs for workflow specification • Sequence • Partial Order with sets • Ex. Method 1 Method3 → Output Method 2 • MBW metamodel as an OWL ontology • MBW generator software • Extract MBW specifications automatically from domain knowledge represented in a WDO DSM Workshop, October 22 OOPSLA 2006
Current Status • Developing and using WDO-Assistant prototype tool to create WDOs • Collaborating with scientists to evaluate the tool • Geophysics • Seismology • Environmental Sciences (Biology) • Volcanology • Developing MBW-Generator software to extract MBW specs from WDOs • XML output • Creating a graphical representation for it • Considering producing MoML and using Kepler’s graphical representation • Need to refine the workflow into an executable specification DSM Workshop, October 22 OOPSLA 2006