SemanTic Interoperability To access Cultural Heritage Frank van Harmelen Henk Matthezing Peter Wittenburg Marjolein van Gendt Antoine Isaac Lourens van der Meij Stefan Schlobach Paul Doorenbosch

SemanTic Interoperability To access Cultural Heritage CH Interoperability Problems Current CH trend: portals that build on heterogeneous collections Different databases/vocabularies/MD schemes

SemanTic Interoperability To access Cultural Heritage

CH Interoperability Problems Current CH trend: portals that build on heterogeneous collections Different databases/vocabularies/MD schemes Syntactic interoperability problem being solved? Access can be granted Semantic interoperability still to be addressed Links with original vocabularies/MD structures are lost

SemanTic Interoperability To access Cultural Heritage

STITCH General Goals Allow heterogeneous CH collections to be accessed In an integrated way Still benefiting from specific collection commitments Keeping original metadata schemes and vocabularies Using Semantic Web means for Representation of different points of view in one system Creation and use of alignment knowledge

SemanTic Interoperability To access Cultural Heritage

STITCH General Goals (2) Research objective: develop theory, methods and tools for allowing metadata interoperability through semantic links between vocabularies Formalization of schemes (and collections) Applying ontology mapping techniques to those schemes Using the results of the mappings in formal reasoning mechanisms (and dedicated interfaces)

SemanTic Interoperability To access Cultural Heritage Applying SW research to concrete objectives Specificity of resources (thesauri, metadata schemes) Formalization in a context of natural semantics What can ontology mapping techniques bring to solve the interoperability problem in CH? Quantitative and qualitative evaluation Integration into realistic scenarios Are these techniques really applicable to the CH case? Uses that have to be further specified What does ‘accessing collections in an integrated way’ mean? Interfaces, services? Anticipating needs that are not yet stabilized

SemanTic Interoperability To access Cultural Heritage Pilot Project Experiment on a reduced scale Choose and formalize 2 collections and their associated subject vocabularies Rijksmuseum ARIA Masterpieces and its “catalogue” KB Illustrated Manuscripts and Iconclass Use existing mapping tools to align vocabularies Adapt/develop a browsing interface providing an integrated access using: Original vocabularies and their structure Alignment information

SemanTic Interoperability To access Cultural Heritage 1 st Collection: KB Illustrated Manuscripts

SemanTic Interoperability To access Cultural Heritage 2 nd Collection: Rijksmuseum ARIA collection

SemanTic Interoperability To access Cultural Heritage PP Modules

SemanTic Interoperability To access Cultural Heritage PP Modules

SemanTic Interoperability To access Cultural Heritage Collection Formalization Goals Analysis of the vocabularies and MD structures Representation using SW languages Testing standard means (SKOS/RDF) Conversion for vocabularies, but also for metadata structures Ontologies providing proper collection-related relations Conversion for interface and reasoning engine (application-specific) but also for formal ontology mapping tools

SemanTic Interoperability To access Cultural Heritage Vocabulary Formalisation: ARIA in SKOS

SemanTic Interoperability To access Cultural Heritage Collection Formalization Problems Interpreting and representing vocabularies using formal standards is hindered by expressivity variation Complex models Fuzzy structures, weakly structured Implies some loss of data during standardisation? Part of the formalization is system-specific Depending on application environment Standard RDFS expressivity and implemented tools Depending on the mapping tools, which might make different hypotheses on the nature of knowledge to align OWL classes vs. nodes in trees Changes the role of the standard representation in the system?

SemanTic Interoperability To access Cultural Heritage PP Modules

SemanTic Interoperability To access Cultural Heritage Automatic Ontology Matching Techniques Generally aiming at recognizing equivalence or subsumption links between ontology elements Lexical Labels of entities, textual definitions Structural Structure of the formal definitions of entities, position in the hierarchy Statistical Objects, instantiation of the concepts Shared background knowledge (“oracles”) Using conceptual references to deduce correspondences Most mapping tools use a mix of such approaches E.g. lexical string matching can ignite a structural alignment process brainLongtumor Long

SemanTic Interoperability To access Cultural Heritage Collection Integration Goals Provide mappers with proper resources Pre-processing done in previous step Use them in the most efficient way Setting taking into account the specificities of CH vocabularies Evaluation/selection of their results Taking into account the use of CH vocabularies in their collection Use their result in the application system Post-processing Do it for vocabularies but also for metadata schemes Not in pilot

SemanTic Interoperability To access Cultural Heritage Mappings

SemanTic Interoperability To access Cultural Heritage Mappings

SemanTic Interoperability To access Cultural Heritage Collection Formalization Problems Input: needs pre-processing, possibly division Output: needs re-interpretation of mapping relations Can confidence measures be used? Alignment process Usually turning to resources that may be absent from thesauri Rich formal/structural information Dually indexed documents Not (properly) using all information found in thesauri E.g. rich lexical information Leading to ‘low-quality’ thesaurus mapping

SemanTic Interoperability To access Cultural Heritage PP Modules

SemanTic Interoperability To access Cultural Heritage User Interface: Access to Collections Adapted faceted browsing paradigm (Flamenco) Search by navigating through several facets STITCH PP facet adaptation: From orthogonal facets (‘material’, ‘location’) to facets describing different conceptual schemes (ARIA, Iconclass) 3 views on integrated collections Single view Combined view Merged view

SemanTic Interoperability To access Cultural Heritage Collections Access: Single View Facets based on 1 point of view and its associated concept scheme(s) Access to objects indexed against concepts from other schemes If mapping between their index and the concepts from single view A single point of view on integrated data set

SemanTic Interoperability To access Cultural Heritage Collections Access: Combined View Search based on 2 (or more) points of view One facet uses 1 vocabulary from 1 point of view Facets attached to the different points of view are presented Simultaneous access to different points of view of the same data

SemanTic Interoperability To access Cultural Heritage Collections Access: Merged View Facets using a merged concept scheme Mapping leads to hierarchical links between schemes Making the links between vocabularies more visible during search A way to ‘enrich’ weakly structured vocabularies

SemanTic Interoperability To access Cultural Heritage Collection Access: Conclusion Prototype is thin layer on top of SW/RDF technology (using Sesame) All data is stored in and retrieved from RDF repositories Easily adaptable for experimentation with different views (without programming) For convincing results you need ‘good quality’ mapping E.g., to assess the value of Merged view Towards application-specific evaluation criteria?