Interoperability:

1. Interoperability: Where the irresistible force of flexibility meets the immovable object of standardization. DRH Conference 2003 Chris Turner Leaders Project UCL SLAIS LEADERS: Linking EAD to Electronically Retrievable Sources

2. Conflicting needs • Flexibility in encoding • Wide range of source materials • Existing practices • Standardisation • Reusability • Support • Sustainability LEADERS: Linking EAD to Electronically Retrievable Sources

3. Interoperability ‘to be interoperable, one should actively be engaged in the ongoing process of ensuring that the systems, procedures and culture of an organisation are managed in such a way as to maximise opportunities for exchange and re-use of information, whether internally or externally’ Miller, Paul. ‘Interoperability. What is it and Why should I want it?’, Aridane, Issue 24 (21 June 2000) http://www.ariadne.ac.uk/issue24/interoperability/intro.html LEADERS: Linking EAD to Electronically Retrievable Sources

4. 6 Aspects of Interoperability • Technical • Semantic • Political/Human • Inter-community • Legal • Informational LEADERS: Linking EAD to Electronically Retrievable Sources

5. Technical Interoperability • the ‘plumbing’, or what goes on out of sight to make documents accessible. • http • tcp/ip • etc LEADERS: Linking EAD to Electronically Retrievable Sources

6. Semantic Interoperability • Works on different levels and enables us to understand and transform documents • Syntactic level • XML rules for well-formedness provide a standardized structure for files • Semantic level • Common convention for naming parts of a document – DTD/Schema • Structural level • Determines how parts of a file relate to each other – the content models described by a DTD/Schema • Content level • What does the document actually say. E.g. Index terms for searching, and lists of descriptors LEADERS: Linking EAD to Electronically Retrievable Sources

7. Interoperability of TEI and EAD documents • they can be moved between computers and accessed between computers • being XML they have a recognized syntactic structure • they use common tag libraries, and thus have consistency of naming. • the content models of the DTDs offer commonly defined structures • the DTDs offer some pre-defined attribute values. LEADERS: Linking EAD to Electronically Retrievable Sources

8. Flexibility of TEI/EAD • A goal of EAD is to make archival resources from many institutions accessible to users. To achieve this goal, EAD must accommodate a wide range of internationally divergent descriptive practices (EAD Working Group, 2002). • It is important to remember...[that] many -- perhaps most -- serious TEI applications have found it necessary to build their own customization of the full scheme in some way (Burnard, 2000). LEADERS: Linking EAD to Electronically Retrievable Sources

9. Consequence No two documents created in EAD or TEI need have the same structural or content markup. • Limits possibilities for data exchange and re-usability • Makes consistent search and retrieval and presentation of results difficult LEADERS: Linking EAD to Electronically Retrievable Sources

10. Solution approach • Determined by project aims • ‘Document-centric’ – focus is on retrieval and presentation of TEI encoded transcripts and images • EAD used for metadata to facilitate search and retrieval • EAC used for contextual information • Reusability of files • Hospitality to existing files? LEADERS: Linking EAD to Electronically Retrievable Sources

11. Contextual presentation LEADERS: Linking EAD to Electronically Retrievable Sources

12. Metadata in EAD file item description in Leaders-EAD to harvest index terms and description from EAD documents resulting index document LEADERS: Linking EAD to Electronically Retrievable Sources

13. Controlled terms for searching LEADERS: Linking EAD to Electronically Retrievable Sources

14. TEI - descriptive markup • Pizza Chef approach helpful • Wide range of formats of archival documents • Descriptive/procedural distinction • But just one DTD. • Modify stylesheets LEADERS: Linking EAD to Electronically Retrievable Sources

15. Examples Example EAC document Example TEI document Application example LEADERS: Linking EAD to Electronically Retrievable Sources

16. TEI DTD modification TEI for Archives DTD Abbreviations entity file LEADERS: Linking EAD to Electronically Retrievable Sources

17. Re-use through Web Services • Standardisation of encoding makes possible standardised application functions. • Application functions described by WSDL (Web Services Description Language) file • Means application developers can incorporate LEADERS functions into their own applications. LEADERS: Linking EAD to Electronically Retrievable Sources

18. Conclusions • Trade-offs • EAD: stricter control vs loss of hospitality to legacy data and variation in existing practices. • TEI: a single DTD but hospitality to a potentially wide range of source materials vs less reusability of stylesheets. • Paradox • More standardisation of encoding vs more flexibility in terms of interoperability. LEADERS: Linking EAD to Electronically Retrievable Sources