Ontology Driven Access to Museum Information

Oreste Signore
W3C Office in Italy at C.N.R.
Area della Ricerca di Pisa San Cataldo - Via G. Moruzzi, 1 - 56124 Pisa
<oreste@w3.org>

CIDOC 2005
Annual Conference
of the International Committee for Documentation
of the International Council of Museums ICOM-CIDOC
May 24 – 27, 2005
Zagreb, Croatia

Slides URI: http://www.w3c.it/talks/2005/cidoc2005/

Paper URI: http://www.w3c.it/papers/cidoc2005.pdf

Acknowledgements

• Giovanni Tumarello (discussion and RDF examples)

Talk layout

• Accessing information on the Web
• Semantics of links and documents
• Role of ontologies
• A possible approach
• Conclusion

Searching vs. Linking

Back to the "roots" of the web

• association is the most important thing
• (semantically rich) links are the real added value
• in the original proposal links had semantics!

The typical search scenario

• search the web
• browse results
• from one ot them, follow links
• perhaps, return to the list of results and resume the browse and link process ...
• ... or issue a new query

Effective search is important ...
... but reducing complexity in query formulation and supporting user's interests is more important

Information Integration

Via a common schema

• in principle the simplest way
• different schemas, different cultural traditions
• failure!

At metadata level

• a typical example: Dublin Core
• the number of metadata vocabularies will continue to grow (M. Doerr)
• doubtful metadata vocabularies can exploit the full richness of possible associations

Talk layout

• Accessing information on the Web
• Semantics of links and documents
• Role of ontologies
• A possible approach
• Conclusion

The basic association model

Reading a document (a web resource) our attention is captured by some words (anchors) leading our mind to a concept space.

Modelling the association process

• anchor leads to a concept
• concept is related to other concepts
• a new concept is related to other resources

Two levels

• data space supports links in their extension
• ontological level supports links in their intension

Implementing intensional links

• identify semantic items
• assign a semantic item to a semantic category (person, location, time, taxonomy, ...)
• support the appropriate interaction metaphor

Other issues

Document semantics

• document structure has a semantics
• semantic (weighted) annotation of document elements and links

Link semantics

• explicit links can be enriched by semantic information (role, meaning of link, ...)
• intensional links can be simulated linking to the appropriate concept in the ontology

User model

• modelled according to the semantic categories
• weighted

Talk layout

• Accessing information on the Web
• Semantics of links and documents
• Role of ontologies
• A possible approach
• Conclusion

Information integration

A base for understanding

Core metadata

• intended for integration
• created, edited, viewed by humans
• human factors play a primary role

Core ontology

• underlying formal model for tools that integrate source data and perform a variety of extended functions
• higher levels of complexity are tolerable
• completeness and logical correctness are the driving forces
• base for deriving knowledge

CIDOC-CRM is a formal ontology which can be used to perform reasoning.

Talk layout

• Accessing information on the Web
• Semantics of links and documents
• Role of ontologies
• A possible approach
• Conclusion

A sample

Epitaphios GE34604

Formal description using CIDOC-CRM

Epitaphios GE34604 (Entity Iconographic Object)
		is identified by
			TA 959a (entity Object Identifier)
			GE 34604 (entity Object Identifier)
		preferred identifier is
			GE 34604 (entity Object Identifier)
	has type
		ecclesiastical embroidery
		liturgical cloth
	current owner
		Museum Benaki (Legal Body)
	has type
		private museum
	has contact points
		<Ifigenia Dionissiadu> ifi@benaki.gr (entity Contact Point)
		Koumbari Street 1, Athens (entity Address)
...

(1998 Martin Doerr and Ifigenia Dionissiadou)

RDF+OWL are fit for the job!

<?xml version="1.0" encoding="ISO-8859-7"?>
<rdf:RDF xml:lang="en" 
   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" 
   xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" 
   xmlns:crm="cd://#" xml:base="//">
	<crm:E84.Information_Carrier rdf:about="Epitaphios GE34604">
		<crm:P2F.has_type>
			<crm:E55.Type rdf:about="ecclesiastical embroidery">
			</crm:E55.Type>
		</crm:P2F.has_type>
		<crm:P2F.has_type>
			<crm:E55.Type rdf:about="liturgical cloth">
			</crm:E55.Type>
		</crm:P2F.has_type>
		<crm:P52F.has_current_owner>
			<crm:E40.Legal_Body rdf:about="Museum Benaki">
			</crm:E40.Legal_Body>
		</crm:P52F.has_current_owner>
		<crm:P55F.has_current_location>
			<crm:E53.Place rdf:about="drawer 8 / case 27 / room 6 / floor sub 1 / new wing">
				<crm:P2F.has_type>
					<crm:E55.Type rdf:about="drawer">
					</crm:E55.Type>
... 

• just a serialization format for metadata: ensures interoperability across SW tools
• OWL meets and exceeds current CRM needs: a number of reasoners available

As a collection of triples

Still in machine domain! Albeit simpler to read, such visualization is still not friendly to humans
(rdf:#type is a shorthand for: http://www.w3.org/1999/02/22-rdf-syntax-ns#type)

A graph visualization

The process

Semantic annotation of documents

• using CIDOC-CRM as a reference ontology
• annotation can reside anywhere
• intelligent agents can use the annotation

User mental model

• preferred interaction metaphors
• stating classess and properties of the ontology the user is interested in (weighted)

Architecture

• browser enriched by reasoner and finder
• reasoner compares userModel and currentResource
• reasoner looks at a trusted ontology and trusted data
• finder searches appropriately the Web

Examples of user interaction

Suppose you are located on a resource ...

Temporal browsing

• events in a neighbour of time of creation
• objects created in the same period

Spatial browsing (from place of production)

• objects created in the same place or nearby
• painting depicting the same place

Spatio-temporal browsing

• artists alive or active in a time interval around time of creation and in the area

Iconographical

• related subject

... and more ...

• the limit is your fantasy (or your needs)

Talk layout

• Accessing information on the Web
• Semantics of links and documents
• Role of ontologies
• A possible approach
• Conclusion

Where's the difference?

Distributed

• many similar stand-alone applications exist
• merging different repositories
• W3C Semantic Web provides basic tools and common ground

Traditional metadata

• emphasis on indexing and searching
• human interface to find the concept
• searching for documents, not following associations

What do we need?

• semantic annotation (who?, how?)
• intelligent agents
• trusted sources
• trust metrics
• visualization and UI techniques

Just visionary?

You may say I'm a dreamer, but I'm not the only one ... (J. Lennon, Imagine, 1972)

Some promising W3C Semantic Web initiatives

• SparQL: RDF query language which standardise syntax and semantics of querying across distributed semantic repositories
• RDF Remote access protocol
• Semantic Web Best Practices and deployment WG: provides "hands on" support for real world use cases

Why not participate in W3C?

Don't ask what the Web can do for you, but what you can do for the Web

Conclusion

• Cultural heritage is rich in associations
• Semantic Web is a true universal information space, where information is machine processable
• Typical search scenario is: find a resource, then follow the links
• Core ontology is a base for understanding and can be used for reasoning
• W3C Semantic Web technologies can support:
  • semantic distributed annotation
  • reasoning
  • technical and semantic interoperability
• Using CIDOC-CRM means gain from years of effort by scholars
• We can work it out

Thanks for your attention

?

If it isn't on the web it doesn't exist ...

... you will find on the W3C Office in Italy (http://www.w3c.it/) web site
the slides (http://www.w3c.it/talks/2005/cidoc2005/)