Workflow Composition Tool in short
Workflow Composition Tool (WCT) is a system that provides workflow composition service.
It is able to transform initial requirements regarding a distributed application meant
to be executed in the Grid environment into a structure of workflow. Such a structure
is often transcribed using graph notation and then uploaded to workflow execution engine.
The tool is targeted for Internet-wide computational environment,
especially for processing
of scientific applications (like simulations). It tries to merge achievements from both
computational Grid and Semantic Web fields to provide semantic-based workflow composition
based on functional service matchmaking.
The Workflow Composition Tool is distributed with the K-WfGrid Project license, which is
accessible here.
What it exactly does
The WCT is designed to automatically construct workflows of distributed applications. In order
to understand it easier we provide a set of definitions we will extensively use in this
documentation.
- Workflow is a set of activities or operations interconnected
together in order to achieve some higher level functionality. The actions are
connected with links that usually express a sort of dependency between them -
like a data dependency: one operation needs some data produced by another
operation. The usual purpose of such workflow is particular type of data being
produced as its output or a particular service being rendered.
- Operation is a workflow basic building block. It represents
some part of the active side of the workflow - it depicts an activity done
inside a workflow for some specific reason.
- Dependency is a link between two operations where one of the
operations depends on the previous execution of another. The notion of
inter-operation dependencies is very important in the workflow composition done
by the WCT.
- Abstract workflow is a kind of workflow that described an application logic but
does not provide any concrete information on how to execute the given workflow. Usually a
workflow in that state could be a subject of reuse as the internal logic of an application
changes less frequent then the details of its execution.
The main purpose of the WCT is to take an initial, incomplete workflow description with user
requirements and based on external source of knowledge to compose a full abstract workflow of
a given Grid application. The way the initial workflow should be provided, the look of the
composed workflow and the sources of knowledge accessed are documented in the subsequent sections
of this documentation.
Important Topics
The following list contains all the important topics to learn about WCT's functionality:
- GWorkflowDL - the workflow description language
used (and understood) by WCT
- Domain ontologies - how to apply them to make the
workflow semantically rich
Publications
The most recent publications regarding WCT:
- T. Gubala, D. Harezlak, M. Bubak, M. Malawski: Semantic Composition of Scientific Workflows Based on the Petri Nets Formalism
in 2nd Int. Conf. on e-Science and Grid Computing, Dec. 4-6, 2006, Amsterdam, Netherlands, (C) IEEE Computer Society Press.
- T. Gubala, M. Bubak, M. Malawski: Support for Automatic Workflow Composition in Semantic Grid Environment
in 5th Cracow Grid Workshop (CGW05) -- Workshop Proceedings, ACC Cyfronet AGH, to be published in 2006
- T. Gubala, M. Bubak, M. Malawski, K.Rycerz: Semantic-based Grid Workflow Composition
in 6-th International Conference on Parallel Processing and Applied Mathematics PPAM'2005,
Lecture Notes in Computer Science vol=3911, 2006, Springer-Verlag
