In pursuit of interoperability: Can we standardize mapping types?

1
In pursuit of interoperabilityCan we
standardize mapping types?

• Stella G Dextre Clarke
• Project Leader, ISO NP 25964

2
Overview

• Compare mapping types used in some well-known
  projects MACS CrissCross RENARDUS KoMoHe
• and in Doerrs well-cited paper on Semantic
  problems of thesaurus mapping
• And in 3 standards BS 8723-4, SKOS and the
  forthcoming ISO 25964-2
• Ask how feasible it is to achieve standardization

3
MACS Project

• Context enabling multilingual access to
  collections indexed with different vocabularies
• Vocabularies are all subject heading schemes
• All mappings are considered equivalence
• Equivalence can be simple or compound
• Two types of compound equivalence
• Heading A Heading B OR Heading C
• Heading A Heading B AND Heading C

4
CrissCross Project

• Context improving access to vocabularies and
  heterogeneously indexed collections (in one
  natural language)
• One-way mappings
• From a subject headings scheme to a
  classification scheme
• Many mappings from one keyword
• Degrees of determinacy rather than distinct
  mapping types D1, D2, D3, D4

5
RENARDUS Project

• Context search/browse across gateways using
  different classification schemes
• One-way mappings, from DDC to local schemes
• Five mapping types
• fully equivalent
• broader or narrower equivalent
• major or minor overlap

6
GESIS/KoMoHe

• Context distributed search across systems using
  25 different vocabularies (thesauri and
  classification schemes)
• (Separate) mappings in both directions
• Three basic mapping types
• Equivalence
• Hierarchical
• Associative
• Also there is an explicit null relationship
• Any mapping can be one-to-one or one-to-many
• Every mapping can have a relevance rating of
  high, medium or low.

7
Doerrs findings(see http//journals.tdl.org/jodi
/article/view/31/32)

• Context query transformation is assumed to be
  the main application of mappings
• All the vocabularies discussed are thesauri,
  applied to documents and/or museum collections
• Basic types of mapping are
• exact equivalence
• inexact equivalence
• broader equivalence
• narrower equivalence
• Exact, broader and narrower equivalence can be
  simple or compound
• Compound equivalence means a Boolean expression
  of target terms using AND, OR or NOT (but in
  practice no examples are given using NOT).

8
BS 8723-4

• Provides for mapping search terms or index terms
• Emphasis on thesauri, although other vocabulary
  types are taken into account
• Basic mapping types
• equivalence hierarchical, associative
• Hierarchical subdivides into broader/narrower
• Equivalence subdivides into simple/compound
• Degrees of equivalence (such as exact, inexact,
  partial) are discussed but not formalised as
  distinct types other than those described above.

9
SKOS (Simple Knowledge Organization System) data
model

• Context is sharing/linking KOSs via the Web
• SKOS development began with thesauri, but has
  extended to classification schemes, subject
  heading schemes, etc.
• Basic mapping properties (skosmappingRelation)
  
• skoscloseMatch (symmetric)
• skosexactMatch (symmetric, transitive)
• skosrelatedMatch (symmetric)
• skosbroadMatch (inverse of narrowmatch)
• skosnarrowMatch (inverse of
  broadmatch)
• No provision for compound mappings

10
ISO 25964-2 (still in draft)

• A revision of ISO 2788 and ISO 5964 as well as BS
  8723
• Provides for mapping search terms or index terms
• Emphasis on thesauri, although other vocabulary
  types are taken into account
• Basic mapping types
• Equivalence
• Hierarchical
• Associative
• Inexact can apply to any mapping, but most
  commonly to equivalence

11
ISO 25964-2 (still in draft)

• A revision of ISO 2788 and ISO 5964 as well as BS
  8723
• Provides for mapping search terms or index terms
• Emphasis on thesauri, although other vocabulary
  types are taken into account
• Basic mapping types
• Equivalence Laptop computers EQ Notebook
  computers
• Hierarchical Roads NM Streets Streets BM
  Roads
• Associative Journals RM Magazines
• Inexact can apply to any mapping, but most
  commonly to equivalence
• Horticulture EQ Gardening

12
ISO 25964-2 mapping types

• Basic mapping types
• Equivalence
• Hierarchical
• Associative
• Inexact can apply to any mapping, but most
  commonly to equivalence

13
ISO 25964-2 mapping types in more detail

• Basic mapping types
• Equivalence
• Simple
• Compound
• Intersecting compound equivalence
• Cumulative compound equivalence
• Hierarchical
• Broader
• Narrower
• Associative
• Inexact can apply to any mapping, but most
  commonly to equivalence, including compound
  equivalence

14
ISO 25964-2 equivalence mappings in more detail

• Simple Laptop computers EQ Notebook computers
• Compound
• Intersecting compound equivalence
• Women executives EQ Women
  Executives
• Cumulative compound equivalence
• Inland waterways EQ rivers canals

15
Intersecting versus cumulative equivalence

• Women executives EQ Women Executives
• Inland waterways EQ rivers canals

16
Some key messages re compound equivalence

• If you use mappings for conversion of index
  terms, you implement intersecting equivalents
  quite differently from cumulative equivalents.
• With simple equivalence (exact or inexact) and
  with hierarchical or associative mappings,
  two-way conversions are usually OK but compound
  equivalence typically works in one direction only.

17
Inexact another complication for equivalence
mappings

• Simple Laptop computers EQ Notebook computers
• Compound
• Intersecting compound equivalence
• Women executives EQ Women
  Executives
• Cumulative compound equivalence
• Inland waterways EQ rivers canals
• Inexact simple equivalence Lawns EQ Turf
• Inexact compound equivalence
• Women executives EQ Females
  Managers

18
Major/minor overlap yet another complication

• Found useful in Renardus project
• Is there a parallel with the KoMoHe relevancy
  rating?
• Earlier versions of SKOS allowed majorMatch and
  minorMatch these were subsequently deprecated
• It would apply to inexact equivalence maybe also
  to hierarchical and associative mappings?
• How would you judge it in cases of compound
  equivalence?
• A recent draft of ISO 25964 admits major/minor as
  an optional attribute of inexact equivalence, in
  the context of a particular application.

19
Now we come to the crunchCan we standardize
these mapping types?

• We can certainly write them in a standards
  document, but can we make them stick? Will real
  users implement them according to the guidance
  rules in the standard?

20
To make a standard stick

• Keep it simple
• Address a real need
• Adopt rules that are already broadly accepted in
  the user community
• Keep it within the implementation range of
  available software
• Make the standard available easily and free or
  at least at a low price
• Commit to lifelong maintenance

21
Want a copy of ISO 25964-2 ?

• A draft is due to appear in January 2011, ISO
  DIS 25964-2, with the hope of attracting
  comments from potential users
• The official way to get it is through your
  national standards body (e.g. DIN)
• Distribution policies vary from one country to
  another last time round we found a way to make
  the draft available online free of charge and
  free of passwords, on the BSI site.
• Send me an email and Ill alert you when the DIS
  is released. stella_at_lukehouse.org

22
References (abbreviated)

• MACS Landry, Patrice. Multilingual subject
  access the linking approach of MACS. Cataloging
  Classification Quarterly. 2004 37(3/4)177-191
  
• CrissCross http//linux2.fbi.fh-koeln.de/crisscro
  ss/swd-ddc-mapping_en.html
• RENARDUS http//www.mpdl.mpg.de/staff/tkoch/publ/
  preifla-final.html
• KoMoHe http//www.gesis.org/en/research/programs-
  and-projects/knowledge-technologies/project-overvi
  ew/komohe/
• Doerr http//journals.tdl.org/jodi/article/view/3
  1/32
• SKOS http//www.w3.org/TR/skos-reference/
• BS 8723-42007 Structured vocabularies for
  information retrieval - Guide - Interoperability
  between vocabularies. British Standards
  Institution
• ISO 25964-2 (still in draft). Thesauri and
  interoperability with other vocabularies Part
  2 Interoperability with other vocabularies