------------------------------------------------------------------------ Date: Mon, 8 Mar 2004 17:08:27 -0500 From: "Rebecca S. Guenther" Subject: Some comments on PB Core To: DC-USAGE@JISCMAIL.AC.UK ------------------------------------------------------------------------ Because I participated in the survey about the PBCore metadata dictionary, I was able to get a sense of some of the issues we might be concerned about in a Usage Board review. I have selected some sample elements to illustrate what some of these issues are. This is not comprehensive. The article in the 2003 conference program is reasonably complete, but does not have as much description and does not include examples, as the survey did. I will bring a copy of some sample elements that shows this additional information. Comments about PBCore 1. They use the "dot" syntax. This has implications for the element names that they have chosen. They need to realize that the refinements will stand alone and not be related to the element they refine except in the RDF expression. Our latest ruling on this was to have refinements be able to stand alone. For example: Title.Program should be programTitle. 2. Example: Title.Series. I question whether this is a refinement of title but of Relation. The semantics of title are: Definition: A name given to the resource. Comment: Typically, Title will be a name by which the resource is formally known. In this case, series is at a different level hierarchically; it is really a related title, that is, the series in which the title appears. Thus I would call it Relation isPartOf or a new refinement isPartOfSeries. We discussed this in the context of the DC-Lib AP and decided to use isPartOf. 3. Type.Form This is described as the manner in which the content of a resource is structured for presentation, viewed or heard by a user. It has a controlled list. It also says it has an implied hierarchy when using Type, Type.Form and Type.Genre. Examples are documentary and tutorial. This distinction is difficult to make and I can't really tell here which is which. I'm also not sure how this so-called hierarchy can be conveyed. 4. Description.ProgramRelatedText. It is described as the actual text or link to text. I imagine this violates the 1:1 principle, since it is really another representation of the program in textual form. 5. Relation.Type This implies that there is an attribute type with a list of values. Those values are what are the refinements themselves (e.g. hasFormat, isFormatOf, etc.). Not the way DCMES does things. 6. Relation.Identifier Specifies that this is free text. Examples include a URI but also includes an ISBN or a string specifying a location (e.g. "Room 217: Section C: Shelf 5"). If it's a URI, it should be identified as a URI (refining Relation). If it's free text, I'm not sure it refines the semantics of identifier: "An unambiguous reference to the resource within a given context. " and we don't generally embed one DC element within another. 7. Creator.Role, Contributor.Role, Publisher.Role We all remember the discussions about this one; the particular role is the refinement. 8. Language.Usage Says it identifies the existence and type of other audio and textual representations of the main audio or language presentation mode for a resource or asset. It has a controlled list that includes "DV1", "SAP1", "Open caption", "DVD Subtitle01", etc. I don't think this is at all consistent with the semantics of language: "Definition: A language of the intellectual content of the resource. Comment: Recommended best practice is to use RFC 3066 [RFC3066] which, in conjunction with ISO639 [ISO639]), defines two- and three-letter primary language tags with optional subtags. Examples include "en" or "eng" for English, "akk" for Akkadian", and "en-GB" for English used in the United Kingdom." This brings up: 1. What does it mean to register an application profile? 2. How much detail needs to go into the review of an AP? Every element? 3. What do we need to say about syntax (i.e., they're using the dot syntax here, appropriate only in HTML)? 4. What if an AP requires some sort of hierarchy in metadata elements?