See also: IRC log
<andypowe11> sorry... i dropped out - not sure why - am back now
<TomB> Scribe: Mark van Assem
<TomB> Scribenick: markva
Antoine: welcome joint meeting DC
architecture group and W3C LLD
... issues with DCAM and APs built on them, explore options,
consequences for future activities
<TomB> can you all hear Antoine well?
<mini> yes, very well
<andypowe11> yes - sound is good
<petej> Yes, fine
markva is scribe
<scribe> Scribe: markva
Antoine: TomB presents his
work
... 2nd presentation Michael Panzer et al
... after coffee break exploration of reqs of APs in context of
subject authority data
... then informal discussion
TomB: with pete johnston, walk
through history of DCAM
... early 2000s: two mindsets: RDF and record format
mindset
... interoperability among DC implementations problematic
... but RDF hard sell: researchy; perceived as flavor of
XML
<mini> antoine, I can hear Tom but not very clearly
<antoine> is it better?
TomB: role of DCAM: bridge
between mindsets; tree struct vs. graphs
... DCAM future: descriptive patterns reflecting existing
metadata practice
... notion of bounded records
... notion of constraints
... (shows diagram summarizing DCAM)
<andypowe11> andypowe11
<mini> @antoine slightly better, but you were clearer earlier :-)
TomB: DCAM can be expressed in
diff syntaxes; RDF/XML, HTML
... common interface for operating across syntaxes
... allows diff applications to communicate
... DCAM family: DCAM, DSP, syntaxes (DC-XML, HTML, DC-Text,
...), user guidance (Singapore Framework, Guidelines ...)
... Description Set Profile Constraint Language: layer on top
of DCAM
... example: book, creator. Template for instances of
Book
... Statement template: slots: property, literal value,
language, Syntax Encoding Scheme
... Statement template for creator, only use slot value
string
... "cookie cutter" for creating descriptions; Book's title is
a literal, creator with dcterms:creator
... wiki syntax for combining template representation and html
presentation of template
... XML syntax for DSPs
... motivation: configure metadata editor; use template to
generate form for entering metadata
... validating metadata
... create OWL expression of constraints
... (diagram of Singapore Framework)
<petej> Yes, fine
TomB: interoperability levels:
informal; semantic; Description set syntactic interop;
Description Set Profile interop
... ~ shared Natural languge, shared formal model, shared
records, shared constraints
... future scenarios: (1) carry on as before (2) DCAM 2 spec,
better aligned with RDF (3) deprecate, continue with RDF (4)
nothing
... (1) interest? editors? review?
(2a) simplified and better aligned with RDF; structural constraints of APs
scribe: impact of DCAM 2 on DCAM
family?
... (2b) goal: clarification; transitional, to be deprecated in
favor of RDF
... (3) negative impact? existing specs status? change in
message? basis for APs gone?
... (4) does DCMI stand behind it or not? reputation?
credibility?
... DCAM abstract syntax vs. RDF
... Descritption (sets) ~ named graphs?
... VES ~ SKOS concept schemes?
... use of rdf:value continues or something else such as
skos:prefLabel?
... Issue: APs
... syntax pattern checks; checking patterns in the graph? Use
OWL with closed world assumption?
... split in Singapore Framework
... constraints in underlying vocabulary or patterns on the
data?
<edsu> what the room looks like (if you are interested) http://www.flickr.com/photos/inkdroid/5105654040/
<mini> @edsu hey, thanks, I was just wondering
<andypowe11> @edsu thanks
Jon Phipps: continue developing DCAM only realistic option
scribe: RDF no notion of record,
DCAM provides that
... enormous value outside RDF world
TomB: remote participants
comments?
... additions to presentation?
<andypowe11> nothing from me at this stage
<andypowe11> i'm lost - is the floor open for discussing the options?
Akira Mijasawa: DCAM DCAM2 differences?
<antoine> @andy : yes
TomB: DCAM2 mostly RDF except
where RDF does not have constructs
... get rid of DC terminology that is mapped to RDF
<andypowe11> ok, i'd like to speak at some point
andypowe11: options 2b, 3 and 4:
all work to RDF, which is where we want to get to
... which of these is better to get to that end game, wrt time
available
... 4 seems not ideal, but less effort
... lean to 3; 2b has political value by taking along
community; but 3 better given time
<edsu> loud and clear :-)
Stu Weibel: frustrated; no productive outcomes all these years
scribe: adopt Web as the
model
... nobody understands DCAM
... W3C published architecture document after actual
implementation
... revive effort: develop reference software; easily drop in
data, generate linked data
andypowe11: support Stu
... DC efforts was trying to say Web is model; got confused
TomB: gap: how to express constraints? Or not necessary?
<jphipps> Just because the DCAM is poorly expressed and poorly understood, doesn't obliterate its value as a model
<jphipps> The world is NOT rdf-centric and is not likely to be
Michael Panzer: was puzzled by description sets; but it does make ontological commitment clear
scribe: bundles of assertions
have to make sense; requires way to communicate this
... RDF struggles with same issues
... DCMI should get involved with RDF development
<jphipps> It's clear to me that even (maybe especially) the creators of the DCAM don't understand its value
mikael nilsson: DC close to data and data production
scribe: lots of RDF data being
produced
... different position now: syntax not problem anymore
... RDF encounters problems that DC has too
<petej> I agree w Andy that the RDF model is where we want to get to, and 3 seems to me the best option, tho I'm willing to be persuaded there is a value in 2b
scribe: look at problems, solve
collaboratively
... DCAM starting replicating stuff in RDF; RDF has broader
base
... DC produces vocabulary that's used in RDF; produces set of
terms not linked to RDF in natural language
presentation by Jeff Young
<kai> Scribe: kai
<andypowe11> i'm going to drop out at this point - can't see presentation or hear very well - sorry
Jeff Young: Introduction to next presentation: Application Profiles in OWL
<antoine> Scribenick: kai
<edsu> andypowe11: thanks for voicing your opinion so clearly
Jeff Young: Want to make sure that I am not that familiar with DCAM and that I come from the Semantic Web world.
<andypowe11> bye all - enjoy rest of the conf :-)
scribe: shows picture of FRBR as
a DCAP domain model
... from SWAP
... simple translation to OWL, classes, properties, ...
... domain and range restrictions are used in OWL
<antoine> jeff going through items at http://www.w3.org/2005/Incubator/lld/wiki/SwapInUmlOwlXsd
scribe: I want to name the things, so I introduced UnnamedAbstraction...
<LarsG> UnnamedAbstraction is a name for the union of Work, Manifestation and Item
<mini> yep
scribe: comparison to UML
diagram
... cardinalities in OWL does not prevent anyone from ignoring
them
<mini> thx...
<JennRiley> TomB: unclear to me if there's widespread support for keeping the dev't of some kind of constraint language. (I think we need this but didn't have a chance to get up to say so.) So I think we should verify the degree of support for that. And if there is support, discuss whether to do it within DCMI or use resources to push this in core RDF
Jeff Young: Example from Toms Presentation with DCAM usage
<mini> I would like to see this done with RDF community on board, in any case.
<petej> TomB: I'm still here but can't hear very clearly
<mini> Even the Topic Maps standard has a CL
scribe: DCMI Type Text is a Class but you can not be sure in the XML representation
<mini> -- http://www.isotopicmaps.org/tmcl/tmcl.html
scribe: in RDF, a subject should
be a concept
... everything else about the concept should be get by
dereferencing
... I cashed it here to let it look more like a record. You
want the additional data here. You want to cache.
TomB: DCAM is historical and DC-RDF is also available.
Jeff Young: This is an example how I progressed.
<TomB> Jeff is showing the first page of XML output extracted by the wiki tool from SWAP
scribe: Now I try to convert that
into OWL
... Types are already there, so let's look at the title
<TomB> Jeff tripped up on fact that the first property cited in SWAP is dc:type (and he thinks in terms of rdf:type).
<TomB> Michael Panzer is coming to the microphone, setting up.
Switch to Michael Panzer
<TomB> JennRiley - let's come back to this during the discussion in the second half
Michael Panzer: Main difference between using OWL for DSP vs. DSP constraint language:
scribe: DSP CL example...
... Title has mincardinality of 1
... title has to be there
... a title with two types would not be valid
... with two types you could infer that both have to be the
same
<TomB> Pellet - an inference language for OWL 2. Has a dialect that treats OWL as a constraint language.
scribe: test with pellet shows
constraint violation
... with removed type it is valid
<TomB> Mikael: Nice because you add the constraints to the class.
scribe: People should remind that OWL approaches constraints in a different way
Maja Zümer: Explains that Work, Expression, ... are no subclasses, so there was a reason to model it that way
Akira Mijasawa: How can we incorporate management properties of the record? Who made it, ... provenance information, management properties
<TomB> Akira: Description set constraints in OWL - how can we incorporate [metametadata]?
Jeff: Named Graphs would be a possible solution, probably not the best, but possible. We can attach properties to graphs
<TomB> Jeff: Create new entity, "record", attach property to that. Not clear how much overlap how much DCAP and how much OWL can express. Not clear to me.
Jeff: Lot of further work to be done, it is not yet clear what OWL can do for us, what DCAM can do...
Coffe Break
<mini> i'll drop out here, thanks for an interesting discussion.
<mini> I'll add a few lines of comments for the discussion later:
<mini> 1. We need very concrete functional requirements, what kinds of constraints do we need? what precisely is "validation"? based on example records and profiles.
<LarsG> Perhaps we should forget about records. We use to think in records because that's what we had, but now we have new possibilities. The metametadata problem is really the same as with provenance, and there's work underway with that, too.
<mini> 2. We can test if OWL with constraint semantics can do it, and if DSPs can.
<mini> 3. The critical question is: based on DCAM, or based on RDF. I certainly prefer the latter, but requires DCMI to adopt RDF.
<mini> I personally see many advantages and potential use cases for an RDF CL that can specify "valid" graphs down to every last triple.
<mini> Now I'm off, good luck!
<petej> I'm leaving too. Thanks for discussions. I think Mikael's closing comments above summarise the key issues/questions very well
Coffe break is over
still scribing
TomB: Repeats minis statements for the audience
Marcia Zeng: Presentation about Application Profiles (based on FRSAD model) for subject domains
scribe: Questions: 1. Why do we
need APs for FRSAD?
... and two more...
... FRSAD conceptual model. Notion of thema: anything that can
be a subject of a work
... different ways to group things
... examples: FRBR, SUMO
... even within one domain it is difficult to map
thesauri.
... In general relationships between themas are
hierarchical
... but there are others, ALA came up with 100s
... different types of KOS have different types to represent
concepts: classifications, theauri, ...
... 2nd question: How formally can the AP be defined?
... communities have different domain models and usage
guidelines
... FRSAD-AP Functional Requirements:
... in general vocabularies, but with specific different
applications
<TomB> FRSAD is a general model. Need more specific models for different types of vocabulary (classification versus thesauri), subject domains (medical vs consumer heatlh)...
scribe: FRSAD-AP domain model: a general model, needs more specific ones for different types of KOS
<TomB> ...what are the characteristics of your subject vocabulary?
KOS = Knowledge Organization System (Thesauri, Classifications, ...)
scribe: Triples have challenges, e.g. how to preserve order
<TomB> ...specify the set of properties in a particular subject domain?
scribe: Nomen specifies
different, general attributes
... Usage Guidlines for FRSAD-AP: Recommendations, e.g. SKOS,
MADS, standards (BS, ISO)
... 3rd question: Difference between APs for subject domains
and descriptive metadata
... serious sameAs issues: Is a concept from one KOS the same
than the concept of another?
@ed: can you continue scribign?
<edsu> yeah
Switch to Gordon Dunsire
Thanks: -)
<edsu> Scribe: Ed Summers
<edsu> ScribeNick: edsu
<TomB> Thank you, Kai!
Gordon Dunsire: Classification/subject schemes
Gordon Dunsire there are things in faceted classification schemes that need application profiles
scribe: semifaceted sub-divisions
also have issues that require AP: DDC, LCSH
... some subdivsions are mandatory in some schemes and optional
in others
... also sequencing is important Law--Sociology,
Sociology--Law
... something that APs need to address particulary for
validation purposes
Gordon Dunsire: FRBRer vs ISBD: OWL vs DCAP
scribe: I'm working with FRBR
conceptual model: nothing mandatory, sequenced or encoded
... monolithic record split into 4 related parts, with some
cardinality constraints
... seems to me the best way to model this is w/ OWL
... e.g Expression is a realization of *exactly* one Work
... not sure how to model that in AP
... contrasted w/ ISBD - which is a data model
... made up 9 separate sections or areas, sequencing is very
important
... there is also 'manditory if applicable" which makes some
things required depending on the resource being described
... seems to me the best way to model that is a DC application
profile
... there are aggregations
... I'm wondering if there need to be 2 separate approaches,
and how others would do it
TomB: any questions?
... I'd like to circle back to the OWL method, I understood
from the discussion before the break that the idea was to model
constraints with OWL, and to validate those constraints with
closed world assumptions
... in pellet the owl is used to generate a sparql query to
validate
... can someone confirm this?
Michael Panzer: pellet is an owl2 reasoner, for doing inferencing ... but there is a project called pellet integrity constraint validator http://clarkparsia.com/pellet/icv/
scribe: it doesn't change
anything in your owl, but it generates sparql queries from the
owl ... the same owl is used for both the inferencing and the
validation
... the integrity constraints wouldn't generate any
inferences
Karen Smith Yoshimura: i'm trying to separate what it is, from what you are doing with it
<JennRiley> edsu: It's Karen Smith-Yoshimura, OCLC Research
scribe: sequencing (how things
are presented) needs to vary on language context, and the
application
... I'm not sure what happens with translations
TomB: i wonder if jon or corey
might have some thoughts
... do RDF and linked data need standard approaches to
"application profiles"?
Stu: do application profiles need to consider RDF/LInked data to be useful?
Antoine: that's a valid question. in rdf there isn't so much guidance on how to reuse vocabularies. i think semweb community could benefit from this
JonPhipps: an application profile at this point is documentation, too many organizations lack the documentation about their data, similar to what mike bergman talked about this morning
TomB: are there only documentation requirements, or do we need to express constraints?
JonPhipps: i'm deeply critical of people who think they have the answers in this space
:-)
TomB: not looking for answers, but suggestions
JonPhipps: if you don't document what your data is, are you really communicating anything? It seems essential for trust.
Gordon Dunsire: i think isbd would be a lot easier to understand as an AP. for communicating what this thing is
emma: i don't feel like i can say what's good for rdf, but the library community needs something that's like AP but for the linked data world
TomB: i'm hearing a requirement
to communicate the purpose and substance of a metadata model to
a community for coherence of data and sharing an approach
... not hearing a clear requirement for standardizing an
approach to modeling constraints for validation. does anyone
want to argue for that?
Gordon Dunsire: look at the FRBR model, if you convert legacy data to that model, having something you can validate aggregations of triples is quite important
JennRiley: i agree, there are two reasons validation is important: it makes tool support easier ; it's also important for public relations, to constrain the world of linked data, and allows you to scope the web of data into manageable chunks (my wording)
TomB: is the Description Set Profile language a good start at that?
JennRiley: i don't have an opinion about whether it needs to be dcmi related
Jeff Young: i think we should come up with some example use cases, it's hard to say -- we are grasping here
TomB: can we identify different scenarios for different types of profiles?
JonPhipps: there is creation
metadata, there is the publishing metadata, and there is the
consumption of the metadata
... there isn't a notion of constraints around publishing /
consuming data for rdf ; those are areas that need to be
covered by an AP
antoine: there is agreement that
some guidance should be provided when using vocabularies, but
does this require a langauge?
... the fact that there was a formal language for the
description set profile wasn't useful to me
JonPhipps: i second that
<emma> Markva asked wether Antoine's comment implied to stop effort on DCAM
TomB: we have the singapore framework, if we ignore the DCAM is the rest valid?
[Singapore Framework diagram on screen]
Diane Hillman: the idea that we will have to explain AP in terms of RDF...i've been through lots of phases of technical wonder. i'm worried that we are getting too far into thinking in one mode, need more general thinking than that
JonPhipps gesturing at large parts of the Singampore Framework diagram and saying it is documentation related
TomB: what about data format?
JonPhipps: that's a specification, perhaps somewhere else like SKOS
(thumbs up from the modelers in the back)
Michael Panzer: the abstract model is a meta model, and in this way in clashes with RDF
scribe: how would you do some of
the things in the DCAM with OWL? are you going to throw out
some requirements?
... we could get involved in rdf next steps. but in the end
dcam and rdf are at odds, and one must win
Stu: Jon's assertion that we have
confused syntax and semantics is a really strong point
... i wonder if someone is willing and able to explain what the
abstract model means. we know how to describe items. i don't
understand the singapore framework. we've got models that we
don't believe. we haven't connected them with what we are
trying to do.
... I'm not saying DCAM or RDF must win. if we were to sit down
and write a document that would not allow us to use models,
triples, domain models ... a plain natural langauge description
of what we are trying to do...i tried to write about it in my
blog and i got feedback that I didn't understand it.
... if you can't describe what the framwork is to practitioners
then we can't move forward
JonPhipps: the value of the upper
two layers is that they allow us to document a domain model, in
a way that is independent of the bottom layer (the
implementation)
... it provides a valuable documentation model, there are bits
that are too technical. it would help to have it rewritten in a
way that's understandable.
markva: could add some documents
that explain it in very clear ways, like what the owl community
has done
... could add some documents that explain how to go from the
conceptual level to the implementation
antoine: keeping the rdf reference you can do without a reference implementation guideline, that might not even express all the requirements
TomB: Michael do you think you can do without this bottom layer of RDF?
Michael Panzer: the question is more where the wind is blowing
scribe: why build it on RDF? do
we do it because it's a good brand, or that it's useful? how
important is that?
... the DC of working with metadata, will enough people find it
useful without anchoring it to the RDF specs?
JonPhipps: perhaps the bottom layer can be informative, and the middle layers would be normative
TomB: adjourned
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