Metadata as Semantic Palimpsests: The Case of PHAIDRA@unipd

This paper illustrates the experience of the Library System of the University of Padova in reviewing the data model of Phaidra (Permanent Hosting, Archiving and Indexing of Digital Resources and Assets), the digital repository for the long-term management and preservation of digital objects in place since 2010, whose system was created and developed by the University of Vienna. In order to provide better informational representation and visualisation of data, both in terms of metadata quality and display, this re-examination consisted in a critical analysis of the foundational metadata profile of Phaidra, its mapping and conversion into the Dublin Core metadata schema (Dublin Core Metadata Element Set 1.1) and, at prototype level, into the Metadata Object Description Schema (MODS). This paper discusses the evidence of the identified solutions being guided by two core principles: on the one hand, the distinctive valorisation of the dual analogue-digital nature of the Phaidra cultural heritage object, on the other, the metadata reuse in the visual function for the graphic updating of the new web interface, which is being done in order to encourage the discovery, even serendipitously, of its content by the digital researcher. Finally, the presentation considers the development activities being carried out by the Phaidra working groups of the Universities of Padova and Vienna, focused on the semantic evolution of the concept of metadata to open data, by presenting here an unpublished example of the Simple Knowledge Organization System (SKOS) prototype and last, but not least, suggesting the definition of a new Phaidra data model.


PHAIDRA@unipd, Discrete features
data heterogeneity in terms of kind of data content as well as of data provenance coming from departments and research centres, archives and museums as well as from libraries' digisaon projects data aggregaon by acng as an a racon for other cultural heritage instuons of the region, PHAIDRA@unipd has a funcon of instuonal data aggregator, that is an organisaon that collects and aggregates, creates and administers metadata from mulple content providers, serving as data service through its Portal and Web-API, as well as data provider by exposing data through the OAI-PMH Protocol

PHAIDRA@unipd, The data model and the reasons for a revision urge
The expansion of this aggregave and meta-aggregave funcon of heterogeneous metadata from similarly heterogeneous origins has raised the urgent need for a crical analysis of the foundaonal data model of Phaidra, both from the point of view of its mapping and conversion into the Dublin Core metadata scheme (Dublin Core Metadata Element Set 1.1) aimed at its publicaon in the OAI-PMH Phaidra data provider, as well as the visualisaon and presentaon of data in the Phaidra web interface

PHAIDRA@unipd, The data model and the reasons for a revision urge
The crucial issue was how to model, expose, and visualise data heterogeneity without losing the intrinsic richness of data sources making heterogeneity interoperable preserving and exploing metadata quality and display Universität Wien metadata, abridged to UWmetadata, is the the foundaonal data model of Phaidra It informs the design of Phaidra metadata, both in terms of representaon of the values as well as the descripon of the contents It is an example of applicaon pro1le being the result of the expansion of the IEEE Learning Object Metadata (LOM) standard (IEEE 1484(IEEE .12.1 -2002 and the combinaon of elements of diGerent metadata namespaces LOM schema is a data model used to describe learning objects or digital resources for educaonal purposes such as learning supports Aimed to establish an inter-schema correspondence of elements, the syntax and semancs of the two schemas involved, adopng a relave translaon mode, namely trying to map each source element into at least one of the target elements, in order to avoid as much as possible any loss of informaon recorded in the source schema Es.: Title → many-to-one: Title → many-to-one: PHAIDRA@unipd, UWmetadata2Dublin Core: crosswalk acvies <ns1:general> <ns1:title language="en">Title</ns1:title> <ns2:subtitle language="en">Subtitle</ns2:subtitle> <ns2:alt_title language="fre">Alternative title </ns2:alt_title> </ns1:general> <dc:title xml:lang="en">ns1:title. ns2:subtitle</dc:title> Alternative title <dcterms:alternative>ns2:alt_title</dcterms:alternative> <mods:titleInfo type="alternative" displayLabel=""> <mods:title>ns2:alt_title</mods:title> </mods:titleInfo> <ns1:general> <ns1:title language="it">La fauna liasica di Vedana (Belluno)</ns1:title> <ns2:subtitle language="it">Pt. 1, Brachiopidi</ns2:subtitle> </ns1:general> <dc:title xml:lang="ita">La fauna liasica di Vedana (Belluno). Pt. 1, Brachiopidi</dc:title> The authorial enty → Person, Instuon has been de1ned from the point of view of the intellectual level of contribuon in the creaon of Phaidra CHO → Creator, Contributor, and role → Phaidra Roles Vocabulary, as well as from that of the mode and form of data value recorded in the source elements In the context of PHAIDRA_DC pro1le, the elements Creator, Contributor de1ne enes who are responsible for making or for making contribuons to the resource, both born-digital and digised By the updated version 1.1 2018, the UWmetadata actor elements embedded also speci1c subelements to host the internaonal standards codes for author iden1caon such as from ORCID, VIAF, ISNI, LCNAF… etc. If the condions 1-4 are not met, then they take the values of the sub-elements Date of Contribute in Provenience, which can represent an uncertain or inferred date of the resource, according to the following modes and forms: 5a) <ns10: date_from> and <ns10: date_to> in <ns10:provenience>, where the two dates are equivalent if precise dates are being a ributed (eg .: 1950) 5b) <ns10: date_from> and <ns10: date_to> in <ns10:provenience>, where the two dates diGer if it intends to assign a set interval of dates (eg .: 1950-1960) 5c) <ns10: date_from> in <ns10:provenience> if an open date interval (eg .: 1950-) are being a ributed.
If the condions set out in paragraphs 1-5 are not met, the element <dc:date> is omi ed The inter-schema translaon of temporal elements is a luminous example of the a empt to represent the heterochronies -this kind of "heterotopias of inde1nitely accumulang me" echoing the words of Michel Foucault referring to museums and libraries, which, in a certain sense, can also be informed by Phaidra cultural heritage objects It has helped to strengthen the methodological aStude for a correct reading of the data, or of reading of the data as "semanc palimpsests" given the stra1ed and permanent coexistence of heterogeneous data models, and their evoluonary and generave funcon in terms of schema, structure, pro1le, model, in aggregate form and as corpora of data, stressing the knowledge that each mapping acvity is an inter-data conceptual negoaon which implies, more than anything else, a mutual understanding and compromise Both the working groups of Phaidra are currently involved in outlining a new foundational data model represented in RDF triples.
By the potential use of an arbitrary number of external vocabularies and ontologies, along with the possibility of RDF graphs to be extended with new nodes and new relationship types effortlessly, this new semanticsembedding model would be much more flexible, extendable to every future needs as well as highly interoperable.
In these terms, the forthcoming achievement of such a framework might thus exactly represent the most effective means to disclose the associative potential of metadata that was quoted at the opening slide of the second part of this presentation.

Future data visions
Thank you!