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RE: Comments on DSpace History System: RDF Schema Design

From: Jason Kinner <jason_kinner@dynamicdigitalmedia.com>
Date: Tue, 3 Jun 2003 19:59:20 -0400
To: "'Tansley, Robert'" <robert.tansley@hp.com>, <www-rdf-dspace@w3.org>
Message-ID: <006301c32a2c$29c72330$0400a8c0@STARGATE>

Rob -

We can definitely model approval, review, and editing as actions/events
in Harmony ABC.  I had assumed that these properties are maintained
after the events themselves for audit purposes.  I do not think it is
useful or descriptive to have a "workflowStep" property with literal
values, because we end up with the same issue that we have now with
other non-URI identifiers.  It may be better to have a model of the
workflow such that each step is a resource that could be referenced by
such a property.  The open question is whether these properties are part
of the action that makes the workflow continue or whether these
properties are part of the item moving through the workflow.

According to "DCMI Metadata Terms" [1], "accessioned" and "author" are
not Dublin Core properties.  I have tried to represent these properties
as sub-properties of sensible Dublin Core properties.  Alternatively, if
there are Dublin Core properties that represent the meanings of these
properties, we could represent them as Dublin Core properties (e.g. -
dateAccepted and creator).

Because the DC registry appears to support only the DC namespace, I
would recommend that we do find DC properties that represent these.
Alternatively, History could provide a reverse map from qualified name
to the appropriate namespace.

-Jason

[1] http://dublincore.org/documents/dcmi-terms/


-----Original Message-----
From: www-rdf-dspace-request@w3.org
[mailto:www-rdf-dspace-request@w3.org] On Behalf Of Tansley, Robert
Sent: Tuesday, June 03, 2003 5:51 PM
To: (www-rdf-dspace@w3.org)
Subject: Comments on DSpace History System: RDF Schema Design


Hi,

Here are my initial comments on the RDF schema design doc.  I should be
able to make the call tomorrow a.m. after all.  Sorry if the notes below
are rambly and confusing, but this stuff is so massively complicated
that it might take me a long time to get together a more polished
version of the comments.  Hopefully I can make things clear in the call.


* Has anyone checked whether the standard DSpace DC type registry
includes element/qualifiers that aren't represented in
http://dublincore.org/documents/dcmi-terms/?  Given that the DC type
registry is configurable, can we rely on/require that everything in the
type registry does come from the list at that URL?


* Eperson Groups:  I've thought about the Eperson Group thing.  There
are two approaches to modelling eperson groups:  have an EPersonGroup
class that is related to Eperson objects via a 'hasPart' property.  This
is more consistent with the way the rest of the system is modelled.  The
other way would be to just represent EPersonGroups as rdf:bags (ordering
etc. is not important).  Maybe the first would be better for
consistency.


* Figure 2: DSpace Object Model

Collection class:  approver, reviewer and (missing) editors may or may
not be present.  The range of these are EPersonGroups.  Perhaps more
importantly, the names 'approver', 'reviewer' and 'editor' might not be
ideal.  Internally in the system, each of the three workflow steps are
just called workflow step 1, workflow step 2 etc.  The fact that
workflow step 1 = 'reviewer' is really just a UI thing.  As the workflow
system evolves, the number of steps may increase and the names change.
Maybe it would be better to use 'workflowStep1' as a property name, or
perhaps 'workflowStep' with some literal property indicating the step
number (not sure how you'd do this in RDF?)

On the other hand, as long as the use of approver, reviewer and editor
is well defined, given that the schema will have to be revised to
accommodate future workflow schemes, perhaps schema versioning means
those names will be OK to use.

Item class:  'accessioned' is part of the Dublin Core metadata; is it in
the Item class as an example or because it is somehow different from the
other DC metadata?

Why does the Item class have a property 'reviewer'?  Aren't reviewers
Agents that are associated with the an event, rather than a property of
the Item?  Items in the DSpace database do have 'submitter' properties,
but not 'reviewer'.

I don't think it's really appropriate to have WorkflowItems and
WorkspaceItems with 'isPartof' properties indicating the Collecion.
They have a target collection, but they are not 'in' that collection yet
since they haven't been approved or accessioned.  I don't know if an
existing ABC or DC property would cover this.

Bitstream: missing 'size' and 'user format description' properties (see
DSpace RDBMS schema)


* 3.3.3 History System Elements:

accessioned, author:  These are Dublin Core fields, shouldn't they be in
that namespace?

copyright:  Copyright is a property of Collection, not Item. It's just
some text that's displayed on the Collection home page in the UI.

hasApprover, hasReviewer: as explained above, isn't the participation of
epeople in workflow expressed in the ABC agent/action/event model?  Why
do we need thse properties?

generated/hasGenerator:  Don't understand why this is here?

introduction:  I assume this corresponds to 'introductory_text' from the
DSpace DB schema; why aren't the same names being used?

license:  This is a property of Collection, which is the text of the
license that submitters to a collection must grant in order to complete
the submission process.  Licenses relating to individual items are held
in Bitstreams within those Items.

firstname/lastname are used for epeople names, 'name' is a property of
Community and Collection only.

provenance:  In the case of an Item, provenance is held within the
Dublin Core metadata.  'provenance' is a property with range literal for
Communities and Collections.


* Appendix A: Example

The examples are rather simple, we need some more complex examples, I
think.  e.g. what happens if a Bundle is removed?  I think this will
raise some issues not addressed anywhere in the current document.


 Robert Tansley / Hewlett-Packard Laboratories / (+1) 617 551 7624
Received on Tuesday, 3 June 2003 19:59:31 EDT

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