Keywords
workflow, semantics, type system, owl, adapter, shim
Start Date
1-7-2010 12:00 AM
Abstract
Scientific workflows describe steps for orchestrating the execution of a networkof computational operators toward some goal, such as data transformation for analysis orvisualization. Typically, these operators consume and emit transformed data, or cause someeffect. In most scientific workflow systems, the operators are typed to enable compatibilitychecks for their composition that make up a workflow. However, type checking performedby most such systems today is still largely confined to syntactic checking with limited, ifany, semantic type checking support. In this paper, we present a type system incorporatingthe W3C OWL ontology language to aid in representing the semantics of data andworkflow operators. We show how this type system supports the detection of typeincompatibility errors in workflow compositions, and how it facilitates a (semi-)automatictype correction procedure using type transformations. We have incorporated our solutioninto Kepler, enabling users to statically test the type-consistency of workflows typed usingour type language, and demonstrate that inconsistent bindings between expressively typedoperators can be automatically corrected via a procedure that seeks to composeadapter/shim functions, such as unit transformations, time series interpolations, or someother arbitrarily complex data transformations.
Semantic validation and correction of scientific workflows
Scientific workflows describe steps for orchestrating the execution of a networkof computational operators toward some goal, such as data transformation for analysis orvisualization. Typically, these operators consume and emit transformed data, or cause someeffect. In most scientific workflow systems, the operators are typed to enable compatibilitychecks for their composition that make up a workflow. However, type checking performedby most such systems today is still largely confined to syntactic checking with limited, ifany, semantic type checking support. In this paper, we present a type system incorporatingthe W3C OWL ontology language to aid in representing the semantics of data andworkflow operators. We show how this type system supports the detection of typeincompatibility errors in workflow compositions, and how it facilitates a (semi-)automatictype correction procedure using type transformations. We have incorporated our solutioninto Kepler, enabling users to statically test the type-consistency of workflows typed usingour type language, and demonstrate that inconsistent bindings between expressively typedoperators can be automatically corrected via a procedure that seeks to composeadapter/shim functions, such as unit transformations, time series interpolations, or someother arbitrarily complex data transformations.
