representing the structural elements of a freely faceted

Representing the structural elements

of a freely faceted classification

Claudio Gnoli (U Pavia)

Tom Pullman (U Cambridge)

Philippe Cousson (L Guérin, Poitiers)

Gabriele Merli (U Pavia)

Rick Szostak (U Alberta)

(ILC Project)

UDC Seminar 2011, The Hague

UDC Seminar 2009

Web-publish or perish !...

[Brickley, Soergel,

Dunshire, Binding, Isaac…]

…but in which format?

UNIMARC ? facets absent [Slavic & Cordeiro 2004; 2005]

SKOS ?

facets “postponed” [Miles 2008]

OWL 2 ? [Zeng et al. 2010]

Facet analysis

“the basis of all methods of IR”

[CRG 1955; Broughton 2006]

Available flavours:

common auxiliaries [DDC, classic UDC]

classic faceted classification [BC2, UDC revisions]

freely faceted classification [CRG, ILC project]

Freely faceted classification

Interdisciplinarity

laws : vessels : oceans : whales : conservation

laws ON conservation

conservation OF whales

whales IN oceans

vessels IN oceans

…

CRG-NATO draft scheme [1960s] V

ILC draft scheme [2004-2011-]

Development continues, but

a stable published edition is needed

for the sake of interoperability

Freely faceted classification

ILC 1

Published on the Web, 2011-07-15

www.iskoi.org/ilc/1/ilc.php

7052 classes,

browsable,

searchable

ILC developing version

www.iskoi.org/ilc/ilc.php

Yellow background

Also

browsable,

searchable

ILC database

Classification

Notational plane

Verbal plane

Idea plane

[Ranganathan]

knowledge representation

Freely faceted classification

Notational elements

Arrays, Chains, Deictics, Facets, Foci, Place of definition of foci, Examples of combinations, Subclasses of a faceted class, Groupings, Related classes

Verbal elements

Main caption, Synonyms, Descriptions, Included terms, Related terms, Notes

Arrays

Sensu Ranganathan Emptying digit z where >25 sister classes

Chains

m organisms

mq animals

mqv chordates

mqvt mammals

mqvtn whales

mqvtni dolphins

mqvtnis Stenella

Field for broader class in DBs for interoperability

Deictics

Ranganathan’s “favoured host class”

Extended in ILC

Facets etc.

Facet Place of definition of foci Caption Synonyms Description

Example of combination

nye estuaries

m8 [ny] organisms, adapted to habitat

m8e organisms, adapted to estuaries

Extra-defined focus (“parallel division” of a facet)

Subclass of a faceted class

The Genesis problem [Broughton 2010]

js6 landforms, modelled by agent

js6i landforms, modelled by wind

js6i:l loess

Relevant for common vs. civil law [Pullman p.c.]

Related classes

In ILC, only dependence relationships are recorded:

xxol alpinism « jsm mountains

Included terms

Related terms

In ILC, disciplines:

Dynamic Web interface

expander link to details depth selector

link to broader class

Representation in SKOS

mqvtn whales, cetaceans, cetacea

V ilc:mqvtn rdf:type skos:Concept;

skos:notation

"mqvtn"^^ilc:ILCNotation;

skos:broader ilc:mqvt;

skos:prefLabel "whales"@en;

skos:altLabel "cetaceans"@en;

skos:altLabel "cetacea"@en.

How to represent facets?

mqvtn2 [jU] whales, in area

V ilc:mqvtn2 rdf:type skos:Concept;

skos:notation "mqvtn2"^^ilc:ILCNotation;

skos:prefLabel "in"@en;

skos:altLabel "area"@en;

skos:broader ilc:mqvtn;

skos:broader ilc:2;

skos:related ilc:jU.

How to represent facets?

mqvtn2 [jU] whales, in area

skos:broader ilc:mqvtn;

skos:broader ilc:2;

Facets are “narrower terms” of both their basic class (mqvtn whales) and their fundamental category (2 in place)

Polyhierarchical model

mqvt 2

“mammals” “in place”

mqvtn2

“whales, in area ”

How to represent facets?

mqvtn2 [jU] whales, in area

skos:related ilc:jU

Facets can be described as “related terms” of their place of definition (jU regions)

but this is not an effective instruction. Some extension of skos:related seems to be needed

Clearly, these are but raw approximations

Alternative:

skos:collection

but conceived for node labels in thesauri,

not linkable to general categories

How to represent facets?

Facet combinations

Not to be all enumerated in SKOS

Possibly a converter ILC > SKOS (and back?) on demand

Other verbal terms

description + its synonyms ~ skos:note

+ related discipline

included terms ~ skos:example

scope etc. notes ~ skos:definition

Conclusions

Some elements of freely faceted cl’s are shared with other KOS types while others are peculiar

Some of the latter (facet categories, place of definition…) are hard to be represented carefully in existing markup languages

Conclusions

FFCs are complex, rich systems requiring special treatment

More representation work is needed, possibly involving SKOS extensions or other markup languages

thanks

www.iskoi.org/ilc