1. 1 Reference Linking in Project Euclid …with some thoughts on the preservation of digital collections. A presentation at the Workshop on Linking and searching in distributed digital libraries University of Michigan, Ann Arbor, University Library March 19, 2002 William R. Kehoe wrk1@cornell.edu Digital Library and Information Technologies Cornell University Library

2. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library2  Context – what is Project Euclid?  Requirements – the constraints for the reference linking system  Implementation – some design views  Next Steps – our plans for the future  Preservation – thinking long-term about digital collections Overview

3. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library3 What is Project Euclid?  A partnership of independent publishers of mathematics and statistics journals  Publishers provide born-digital versions of their print journals.  http://projecteuclid.org http://projecteuclid.org

4. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library4 Reference Linking: two viewpoints  The publisher’s point of view Links to multiple resources add value to the electronic version. MR numbers, CrossRef DOIs, web links are included in the reference when we find them  The library’s point of view The appropriate copy problem—does a link lead to a copy for which the library has viewing/distribution rights. Is the copy an authentic representation of the original?  Project Euclid represents publishers

5. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library5 Purpose References in article files are made available as links on HTML abstract pages >

6. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library6 Requirements  Automatic processing  Extensibility to multiple reference styles  Extensibility to multiple input formats  Low-cost maintenance  High accuracy

7. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library7 Implementation Conversion Extraction Parsing Look-up Creating Links Storing > Title Author and affiliation Abstract goes here Body References > Title Author and affiliation Abstract goes here Body References

8. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library8 Conversion The converter is Derek Noonberg’s “pdftotext” utility. http://www.foolabs.com/xpdf/home.html > Title Author and affiliation Abstract goes here Body References Title Author and affiliation Abstract goes here Body References > Title Author and affiliation Abstract goes here Body References Title Author and affiliation Abstract goes here Body References Converter

9. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library9 Conversion/Extraction activity diagram

10. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library10 Extraction A fragment of the perl module that extracts the references from the text version of an article

11. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library11 Object view Reference MRNum Year Title DOI Journal String LinkedString Parsing Method Factory getMRNum() getYear() getDOI() getTitle() getJournal() … more …

12. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library12 Parsing Each element of a Reference is extracted by a subroutine customized for how the element appears in a particular journal style.

13. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library13 Look-up |IEEE Trans. Automat. Control|chang||||1994||||Stability, queue length and delay of deterministic and stochastic queue |SIAM J. Control Optim.|Dupuis||||1989|||| Query Result set  0018-9286|IEEE Trans. Automat. Control|Chang|39|5|913|1994|||95b:90029|Stability, queue length, and delay of deterministic and stochastic queueing networks.  |SIAM J. Control Optim.|Dupuis||||1989||||

14. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library14 Link Creation  [Ar] V. ARNOLD, A-graded algebras and continued fractions, Comm. Pure Appl. Math. 42 (1989), 993­1000.  [Ar] V. ARNOLD, A-graded algebras and continued fractions, Comm. Pure Appl. Math. 42 (1989), 993­1000. MR 90h:32025 An HTML anchor tag is inserted into the reference string and saved to an XML file. The User Interface module later uses the linkedString element when creating an Article Abstract page on the fly. It doesn’t have to know how to create the link.

15. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library15 Storing … more elements … … elements … Stored as an XML file

16. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library16 …an HTML link on the article’s abstract page … Display An element in an xml file provides… … which links to a MathSciNet page

17. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library17 Next Steps  More journals  Adding DOIs to the abstract page  Conversion from LaTeX files  Digitized back issues

18. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library18 Addendum on Digital Preservation  Libraries and others are considering ways to preserve our digital resources for the long term.  One possible solution is the LOCKSS system (Lots of Copies Keep Stuff Safe)LOCKSS  Another solution is to preserve the metadata needed to describe and reconstruct a collection while preserving and providing access to the data files. The Consultative Committee for Space Data Systems has published a Reference Model for an Open Archival Information System (OAIS). Many of the persons working with digital collections in the library and archive world are using this model to plan for long-term preservation.Consultative Committee for Space Data SystemsReference Model for an Open Archival Information System (OAIS)

19. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library19 From the Reference Model for an Open Archival Information System (OAIS)Reference Model for an Open Archival Information System (OAIS) Archival Information Package Preservation Description Information Representation Information * 1 Data Object > Digital Object Content Information Reference Information Provenance Information Fixity Information Context Information Most digital collections contain some form of the objects in blue. OAIS-compliant systems also contain the metadata objects in yellow

20. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library20 OAIS Functional Model From the Reference Model for an Open Archival Information System (OAIS)Reference Model for an Open Archival Information System (OAIS)

21. March 19, 2002William R. Kehoe, Digital Library and Information Technology, Cornell University Library21 For More Information…  Project Euclid—http://projecteuclid.orghttp://projecteuclid.org  MR Batch Lookup—http://www.ams.org/mrlookup- support/technical_help.html#httphttp://www.ams.org/mrlookup- support/technical_help.html#http  Consultative Committee for Space Data Systems— http://www.ccsds.org http://www.ccsds.org  Reference Model for an Open Archival Information System (OAIS)—http://www.ccsds.org/documents/pdf/CCSDS-650.0-R- 2.pdfhttp://www.ccsds.org/documents/pdf/CCSDS-650.0-R- 2.pdf  LOCKSS—http://lockss.stanford.eduhttp://lockss.stanford.edu