OAIS structures metadata around a single entity – the archived content (Content Information). PREMIS structures metadata around four entities (Objects, Agents, Rights, and Events). The PREMIS Object entity roughly corresponds to OAIS’s Content Information, but there are no equivalent OAIS entities for Agents, Rights, or Events. So when we did the mapping we decided to extend the information types defined in OAIS to each of the PREMIS entities. So for example, Reference Information is used to identify Content Information; by extension, Reference Information identifies an Event. Provenance information records various aspects of the Content Information’s history; by extension Provenance information records various aspects of an Event’s history (e.g., when it occurred, what its outcome was, etc.). As you point out, this approach does not strictly adhere to the OAIS definitions, but we thought it worked pretty well.
Alternatively, you could retain the OAIS principle that all metadata is structured around the Object; in this case, you might say, for example, that all Agent-related metadata is part of an Object’s Context Information (if you accept the proposition that Agents are part an archived object’s context). There is some merit in this approach as well.
Anyway, this was the thinking that went into the mapping. However, it is not set in stone, it was just a way to set the PREMIS metadata in an OAIS context. Alternative approaches and mappings are welcome!
Sent: Tuesday, August 22, 2006 11:51 PM
To: [log in to unmask]
Subject: [PIG] OAIS : PREMIS mapping question
I've been looking at the OAIS/PREMIS mapping docs on the swiki and I'm not sure I completely agree with the mapping of the entities other than Object. Perhaps someone else can explain for me...
The easiest way for me to illustrate is with an example. The Excel spreadsheet and diagrams in the PowerPoint presentations show a mapping for the identifier semantic units for the agent, event and rights entities to OAIS Reference Information. However in the OAIS it states that Reference Information pertains to "identifiers for the Content Information."
The identifiers for the entities other than Object are not identifiers for the Content Information, they are identifiers (pertaining to PREMIS entities) to reference and structure the metadata about events, agents and rights in the Context Information and Provenance information (and perhaps Fixity Information depending on the event type).
Do you see my point or am I off on another planet missing the real world?
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