Global Model Exchange (GME)

Originally developed as part of the Mobius Project, the GME or Global Model Exchange, provides a distributed service infrastructure for the coordinated management and discovery of data types used on the grid.  In order for services on the Grid to communicate with each other, their data must be described in a format that is understood by all necessary components involved. Thus a data management system for the Grid must provide a method for defining metadata and data via a universal consistent modeling pattern, distinct instances of which we call data models. The "data model" is the specification of the structure, format, syntax, and occurrences of the data instances it represents.

The models must be globally available to every (authorized/authenticated) service to enable the system to work. To get around the problem that data models from different areas and institutions, though they may define a similar entity (a Patient entity, for example), will not necessarily be equivalent, entities within models are assigned to a namespace that effectively makes a Patient entity from one institution distinct from a Patient entity at another one. Another issue is persistence and availability of models. Data and the data models registered with the GME ought to persist and be attainable from any node within the GME.

To these ends, the GME is responsible for storing and linking data models as defined within namespaces in a distributed environment. It enables other services to publish, retrieve, discover, remove, and version metadata definitions (data models). GME services are composed in a DNS-like architecture, in which parent-child namespaces organize the connection of nodes into a hierarchical tree structure.

caBIG has adopted the GME to maintain the structural definitions of the data models which are exchanged on the grid.  Continued enhancements to the GME are being developed as part of the caGrid effort.

Project Researchers

David Ervin
Shannon Hastings, M.S.
Stephen Langella, M.S.
Scott Oster, M.S.

Project Publications