ApplicationProfile - Raymond Yee's Wiki

Today I decided that I needed to get a better handle on what an "application profile" actually is. My rough understanding is that specifications like METS and IMS-CP are so broad in structure and intended use that a particular community of practice might want to go for a narrower interpretation of the specification -- kinda like subclassing a object type in object-oriented program. For instance, one might want to create a MetsForBerkeley that is still a METS document.

But I figure that I should try to find more rigorous definitions out there. A good lead, I figured, would be CanCore, which actually has a FAQ on What is an Application Profile. This FAQ points to two other very useful sources:

Metadata Principles and Practicalities by Duval, Hodgins, Sutton, and Weibel
The Z39.50 Information Retrieval Standard by CliffordLynch.

Let me quote from the article by CliffordLynch:

Various groups have been developing Z39.50 profiles. The maintenance agency keeps a list of these, but the process by which they are approved and subsequently maintained remains somewhat unclear. Profiles are basically customizations of the standard to particular communities of implementors with common applications requirements. A profile may include a whole range of agreements: for example, agreements to use or not to use specific optional version 3 features; agreements on particular attribute sets and record syntaxes to be used (including perhaps the definition and registry of new attribute sets and/or record syntaxes to support the community in question); and even agreements on what extended services will be used (including, again, definitions of new extended services that the profileís community may want to use). Often it is doubtful how much meaningful interoperability will be possible between one Z39.50 implementation that is built according to a given profile and another which is not aware of the specific profile. Examples of profile work include GILS, the Government Information Locator System; the Museum Interchange Profile being developed by the Computer Interchange of Museum Information (CIMI) group; the Digital Collections profile under development by the Library of Congress; the (revised) WAIS profile; profiles for applications involving remote sensing and geospatial data, and a cataloging profile under development by the National Library of Australia.

In the MetsSpec context, we have METS Profile Requirements, which is under review as of 2003-08-21.

Other references that look useful: