LOD in Digital Libraries - Current Issues

Transcription

1 LOD in Digital Libraries - Current Issues Ansgar Scherp a.scherp@zbw.eu FG Datenbanken March 2014 Braunschweig

2 Index Newly Acquired Media Ancient world: Library of Alexandria Today: database-oriented systems Tomorrow: Web Semantic Web in Libraries -2-

3 SWIB = Melting point for librarians that work with LOD Start: 2009 Today: International Meetup - 3 -

4 The Early Years (they were grey) Individually implemented solutions; proofs of concepts First LOD cloud: emerged in May 2007 First Linked Library connection between Library of Congress, US and Swedish National Library Quick adoption of new technology - 4 -

5 Linked (Library) Data: A Success Story - 5 -

6 Current (Technological) Issues * ) 1. Entity resolution 2. Schema matching 3. Distributed data management 4. Automatic indexing 5. Indexing non-textual content 6. Data provenance Out of scope here (but equally important) Quality management (e.g., automated indexing) Legal aspects Job market * ) Disclaimer: No guarantee for completeness - 6 -

7 1. Entity Resolution URI aliases to connect resources Describing the same things in the real world Service for sameas-links:.org Source Persons Organizations DBpedia 364, ,000 Library of Congress Authorities 3,800, ,000 German National Library Authority File 1,797,911 1,262,404 Virtual International Authority File 10 million 3.25 million Resolution of name, co-authors, title, and venue often not sufficient Source: J. Neubert, K. Tochtermann: Linked Library Data: Offering a Backbone for the Semantic Web, CiCIS,

8 Example: DNB GND on Helmut Kohl -

9 VIAF(Virtual International Authority File) Combines multiple name authority files Lower costs and increase utility of library authority files Matching and linking widely-used authority files and making that information available on the Web - 9 -

10 2. Schema Matching When defining one s vocabulary, refer to definition of concepts and properties of existing vocabularies Goal: data becomes self-descriptive Integration of vocabularies is hard Similar to the problem of identity Example: foaf:name vs. vcard:family-name Can be complex, even for very similar vocabularies

11 Example: STW and TheSoz Standard Thesaurus Wirtschaft TheSoz (GESIS) Manually created mappings (mostly 2004/2005) OAEI Library Track for ontology matching (since 2012) Also connected to GND and ACROVOC

12 Example: STW and TheSoz Standard Thesaurus Wirtschaft TheSoz (GESIS) Manually created mappings (mostly 2004/2005) OAEI Library Track for ontology matching (since 2012) Also connected to GND and ACROVOC

13 egov Example: Crimes in US vs. UK Same or different? Same or different?

14 3. Distributed Data Management Sep. 2012

15 VIAF Example Robert Moses (American Robert Moses city planner) Papers Source: Trevor Thornton Linked Data for Librarians Senior Applications Developer, NYPL Labs The New York Public Library mss/ ms/extent 142 linear feet s/creator /arch#heldby mss/2071 Robert VIAF s/subject ms/creator oclc/ Other work by Caro Robert Caro writes The Power Broker about Moses

16 3. Distributed Data Management Federated querying Index structures (what information is where?) SPARQL-based vs. traversal-based querying Ranking of results User s expect same behavior as in web search First hits implicitly more important and relevant DFG project LibRank at ZBW

17 4. Automated Indexing Delivered publications per year (print/online) at DNB Automated classification of PDFs into 100 classes ( Sachgruppen ) in PETRUS project at DNB Source: E. Mödden Zukunftsfähige Inhaltserschließung Strategien und Perspektiven in der Deutschen Nationalbibliothek, GBV,

18 4. Automated Indexing DFG project GERHARD in 90s on automatically indexing scientific Web content (involved ) ~ 1 Mio documents crawled and automatically indexed Classified using the concepts from the Universal Decimal Classification (UDC) Trilingual (German, English, French) Single server machine ~ 750 MB RAM Oracle RDBMS with full text indices ConText (today: Oracle Text)

19 GERHARD

20 Erschließung in Auto-completion suggests terms from PND, STW, Author confirms by selecting terms Keyword is matched with the semantic concept

21 5. Indexing non-textual content Mapping scientific content with social media For example, PDFs + blogs, tweets, research data, Structured scientific content (fulltexts, paragraphs, citations, ) Content analysis Informal + hasty content from social media channels Linking to EEXCESS topics/ objects/ users

22 6. Data Provenance VIAF: inter-organizational and cross-border and thus cross-lingual record linkage How to track metadata (re)use? How to refer to original metadata when library A uses a (part of) record from library B?

23 Europeana Data Model Source: Slide adopted from Kai Eckert Provenance of the meta data Provenance of Mona Lisa

24 DM2E Data Bridge for Legacy Systems

25 Resource Description and Access New cataloging code to replace AACR2 from 1978 Describe content, online But not to confuse with RDF Inspired by Functional Requirements for Bibliographic Records (FRBR) Applicable to any kind of resources ( not only books ) Provides guidelines

26 FRBR in a Nutshell Work is realized through Much more than just a boring bibliographic data record Group 1 Expression is embodied in recursive one many Manifestation is exemplified by Item 26

27 ZBW Services and Data Leibnitz Information Center for Economics (Kiel and Hamburg) 200+ employees, 3 professors (Scherp, Tochtermann, Peters) Annual budget of 20,8 mio open access documents Intelligent use of STW 1 mio Open Access documents 4,9 mio documents Couple of thousand unique visitors per month

28 Got Interested? Contact me: Ansgar Scherp Web:

29 FRBR or What is Beauty? Work Expression Manifestations Items Source: Lynne Chase: Resource Description and Access, Emporia State U., Fall 2009