The coarse-grained approach treats workflow engines as distributed black box systems, where complete sub-workflows are sent to pre-existing enactment engines.

The SHIWA project has developed a workflow embedding and invocation solution that enables users to create P-GRADE native (or parent) workflows that can incorporate non-native (or child) workflows of other workflow systems.
The solution is based on the integration of the P-GRADE portal and workflow system and the GEMLCA application repository and submitter to deploy and invoke different workflow engines. Although the solution is based on the P-GRADE workflow system, GEMLCA can be integrated with other workflow systems. Therefore, it can be considered as a general solution that can be adopted by other workflow systems through integration of the GEMLCA client to them.
This integration will enable other workflow systems to execute non-native workflows if their workflow engines are deployed in a GEMLCA Service. Based on previous work, Kepler, Taverna, and Triana engines were already connected to P-GRADE via GEMLCA.

The CGI approach supports two execution modes. In workflow engine invocation mode the workflow engine is pre-deployed on a dedicated machine. In the workflow engine submission mode workflow engines are submitted to computational resources upon invocation. The SHIWA project will support both modes.

The fine-grained approach addresses language interoperability by defining an intermediate representation to be used for translation of workflows across systems such as ASKALON, Pegasus, P-GRADE, MOTEUR, Triana.