---------------------------------------------------------------------- Date: Tue, 21 Mar 2006 11:04:37 +0000 From: Pete Johnston Subject: Re: Updated Wikipedia article To: DC-USAGE@JISCMAIL.AC.UK Diane I. Hillmann wrote: > Folks: > > I went in and changed the page: http://en.wikipedia.org/wiki/Dublin_Core > using stuff from "Using Dublin Core" primarily. > > You're welcome to see what you think and do some editing yourself, if > you've a mind to do so. I won't take it personally, I promise! I haven't edited the document on Wikipedia (yet), and I don't really want to do so unilaterally, but (and this really applies to other introductory resources like the "Using Dublin Core" document and like the conference tutorials) I think that the role of the DCMI Abstract Model as providing the conceptual framework for DC should be presented more "up front" e.g. there should be a short/simplified summary description of the DCAM in the introductory section, or as a separate section following the intro and before the discussion of Simple DC and Qualified DC. Mentioning the DCAM _only_ as a tool for comparing different syntaxes is only telling half the story (IMHO) - though I think the DCAM doc itself might be slightly more "bullish" in its own intro paragraph! ;-). Now sure, I appreciate that that might look like a case of "historical revisionism" to the casual observer who knows "the 15 elements came first" (or indeed only knows the 15 elements), but I do think we need to shift firmly towards putting the DCAM at the centre of our explanations of "what DC is". (If people want a history of the evolution of DC, and how DCMI got from "the 15 elements" to "the qualifiers" to the grammatical principles to the DCAM, OK, that's fine, but that's a different document.) I recognise this probably goes against the way we've tended to introduce DC, but I'd go as far as saying that it is confusing/unhelpful to start talking about "elements" without first describing the DCAM, at least in some way - maybe not every fine detail, but the fundamental points about making statements that assert relationships between resources and values. Without such "contextual" information, it just begs the question of what an "element" is. It makes a "leap of faith" that readers already share a common understanding of what an element is, but (as we've found out somewhat painfully over the last few years), that is not the case: the term "element" is used to refer to different things in different contexts and readers draw their own (different, incompatible) conclusions ("Ah, they're talking about XML elements", "Ah, so they're referring to things like LOM elements", "Ah, they mean attribute-value pairs" etc etc etc). I think the account of "Simple Dublin Core" also blurs the distinction between the DCMES as a set of terms, each of which may be deployed in many different "DC application profiles" with different constraints on their usage in a description set, and "Simple Dublin Core" as one such DCAP with one particular set of constraints. And in the account of "Qualified DC" I'm not sure the word "value" is being used in the way it is used in the DCAM. I think phrases like "the value may still be useful to a human reader" suggest that the reference is to (what the DCAM calls) "value strings". ---------------------------------------------------------------------- Date: Tue, 21 Mar 2006 11:55:30 -0000 From: Andy Powell Subject: Re: Updated Wikipedia article To: DC-USAGE@JISCMAIL.AC.UK Yes, I agree with this... though it's certainly not easy to come up with the one paragraph summary of what DC is. That's one of our problems! But talking about 'elements', 'simple' and 'qualified' doesn't help much! Here's my stab at a summary... --- cut --- Dublin Core (DC) is a metadata standard for describing a wide range of digital, physical and conceptual resources (i.e. just about anything!). A DC description is made up of a set of statements, each of which comprises a property/value pair. Typically, the described resource is identified using its URI and the value is either identified using its URI or represented using a simple string (the 'value string'). In many cases, multiple descriptions are combined in order to build up richer descriptions ('description sets') about related groups of resources. For example, in describing a digitised painting, it may also be appropriate to describe the original painting from which the digitisation was made and the original artist, thus creating a description set of three related descriptions. Statements may be refined by indicating the language of the value string, any data-type ('syntax encoding scheme') to which the value string conforms or the class ('vocabulary encoding scheme') from which the value is taken. Properties, syntax encoding schemes, vocabulary encoding schemes and concepts in controlled vocabularies are known as 'terms'. All terms in DC metadata are assigned URIs, and schema languages are used to indicate the relationships between them. The features of the DC metadata standard are fully described in the Dublin Core Abstract Model (DCAM). The Dublin Core Metadata Initiative (DCMI), the body that facilitates the community development of the DC metadata standard, provides a core set of about 80 properties, encoding schemes and controlled vocabularies from which descriptions can be constructed, but encourages communities to create additional terms as necessary, within the framework provided by the DCAM. Finally, the DCMI community has defined three encoding syntaxes that can be used to encode DC metadata records for exchange between software systems and services using XHTML, XML and RDF. Historically, DC refered to properties as 'elements' and is perhaps best known for the Dublin Core Metadata Element Set (DCMES) - a set of 15 elements, created originally to support the discovery of resources on the Web. --- cut --- This, rightly(!), relegates DCMES to a footnote and doesn't even mention simple and qualified! :-) On the face of it, it may seem harder to grasp than the traditional 'element', DCMES, 'simple DC', 'qualified DC' approach - but I think that is largely to do with where we come from. Personally, I think it is much clearer - it emphasises what is important and ignores what can safely be forgotten. ---------------------------------------------------------------------- Date: Tue, 21 Mar 2006 12:06:53 -0500 From: "Diane I. Hillmann" Subject: Re: Updated Wikipedia article To: DC-USAGE@JISCMAIL.AC.UK Tom, responding to Pete and Andy: >I agree that the Abstract Model should be at the center of >explanations, and I like most of the text. I also think we >need to revisit the explanation for "simple" versus "qualified" >Dublin Core. I agree that the Abstract Model should be better integrated into the text, and have said more than once that I'd like to find a way to integrate the AM better into "Using Dublin Core," but could use some help with that. Because I used text from "Using Dublin Core" as the basis for what I added to the article, it suffers from some of the same problems. >Two issues however: > >1) To start with statements, property-value pairs, and URIs is > to jump in at the deep end. The notion of "core metadata > properties" has been and should continue to be a key part > of the message. Introducing "the Dublin Core" up-front also > helps explain the funny name. > Yes, in my experience, the DCAM certainly is the deep end for most people. I think it makes more sense to use Wikipedia to provide a "soft" approach, dealing first with things people might have already heard about DC, and making that clearer before getting into deeper water. > > The Dublin Core Metadata Initiative (DCMI), the body that facilitates > > the community development of the DC metadata standard, provides a core > > set of about 80 properties, > > I suspect that the notion of "core metadata properties" really > is easier for most people to grasp than the notion of an > abstract model. I would not want DCMI to lose that focus -- > 80 properties is no longer really a "core". Agreed. Despite our mere 10 years of "legacy," we are seen by many in an increasingly complex world as more approachable and understandable--metadata for the masses, perhaps. We can't afford to lose that advantage. >2) "DC" and "DCMI" > > > The features of the DC metadata standard are fully described > > in the Dublin Core Abstract Model (DCAM). Usage aside, I think the sentence above denies the fact that the explanation provided in the DCAM, while certainly full, is fairly technical from the point of view of the metadata novice. > This is not quite how I understand our current use of > "DC" and "DCMI". To take two important examples, we > currently have the "DCMI Abstract Model" and we talk > about "Dublin Core Application Profiles" (but not "DC > Application Profiles" or "DCMI Application Profiles"). > In a reasonably consistent way, we currently: > > -- use "Dublin Core" instead of "DC". The exception is when > we use the names of Jiscmail lists as handles for working > groups (e.g., "DC-Architecture"). In DCMI publications, > we have I think avoided using the free-standing acronym > "DC" to mean just "Dublin Core" for quite a long time. > If we were to revive it, would we do so with the intent > to refer to "the Dublin Core" (DC-15) or to designate > the abstract model? > > -- use "DCMI" for things that are managed or maintained by > DCMI as an organization -- e.g., "DCMI Usage Board". > The DCMI Abstract Model is a model put forward and > maintained by DCMI for metadata that uses DCMI terms, > (whereas a Dublin Core Application Profile is in most > cases not put forward or maintained by DCMI). I *think* I followed most of this pattern, but may have blundered a bit ... ;-) ---------------------------------------------------------------------- Date: Wed, 22 Mar 2006 07:52:51 +0000 From: Pete Johnston Cc: DC-USAGE@jiscmail.ac.uk Subject: Re: Updated Wikipedia article Quoting Thomas Baker : > Two issues however: > > 1) To start with statements, property-value pairs, and URIs is > to jump in at the deep end. The notion of "core metadata > properties" has been and should continue to be a key part > of the message. Introducing "the Dublin Core" up-front also > helps explain the funny name. > > > The Dublin Core Metadata Initiative (DCMI), the body that facilitates > > the community development of the DC metadata standard, provides a core > > set of about 80 properties, > > I suspect that the notion of "core metadata properties" really > is easier for most people to grasp than the notion of an > abstract model. I would not want DCMI to lose that focus -- > 80 properties is no longer really a "core". Unless we explain what we mean by "property", and show how properties are used in DC metadata (to construct simple statements that assert relationships between resources), then we are left with the same problem with the word "property" that we have now with the word "element". Agreed, "property" maybe comes with slightly less "baggage" than "element", but I've had experience of people picking up on my tendency to use "property" rather than "element" and altering their usage accordingly. But unless I explain why I'm saying property - what a property is - then they think I'm using it simply as a synonym, and they start using "property" for all the contexts in which they were using "element", including ways which are inconsistent with the DCAM. And - perhaps even worse - they start to apply the term "property" to things defined in other meta-models - where those thinga are not properties at all, and the "native" (to that meta-model) term "element" is indeed the most appropriate term. Whatever we call the fifteen things, we have to explain what they are and how they are used. ---------------------------------------------------------------------- Date: Wed, 22 Mar 2006 13:34:49 -0000 From: Andy Powell Subject: Re: Updated Wikipedia article To: DC-USAGE@JISCMAIL.AC.UK > I suspect that the notion of "core metadata properties" really > is easier for most people to grasp than the notion of an > abstract model. I would not want DCMI to lose that focus -- > 80 properties is no longer really a "core". OK, could drop the specific ('80') and leave the general ('core set of ...')? But main problem is with emphasis and order. It's difficult to say what DCMI provides (essentially 'a core set of terms that can be used to create descriptions of resources') without describing the nature of what those terms are and how they fit together. Perhaps in my suggested text, The Dublin Core Metadata Initiative (DCMI), the body that facilitates the community development of the DC metadata standard, provides a core set of about 80 properties, encoding schemes and controlled vocabularies from which descriptions can be constructed, but encourages communities to create additional terms as necessary, within the framework provided by the DCAM. needs to be moved up front and changed to The Dublin Core Metadata Initiative (DCMI), the body that facilitates the community development of the Dublin Core metadata standard, provides a flexible and extensible metadata framework and a core set of terms from which descriptions can be constructed, but encourages communities to create additional terms as necessary to meet their own descriptive requirements. Then go on to describe the framework (the DCAM) in more detail... Does that help? > 2) "DC" and "DCMI" > > > The features of the DC metadata standard are fully described > > in the Dublin Core Abstract Model (DCAM). > > This is not quite how I understand our current use of > "DC" and "DCMI". Sorry. I was writing in a hurry so I didn't follow corporate guidelines! :-)