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Re: questions about notations / sizes / coordination

From: Alistair Miles <a.j.miles@rl.ac.uk>
Date: Wed, 19 Jul 2006 15:19:33 +0100
Message-ID: <44BE3F75.7030605@rl.ac.uk>
To: Jakob Voss <jakob.voss@gbv.de>
CC: public-esw-thes@w3.org

Hi Jakob,

Somebody is awake and we are definitely interested :)

Regarding notations, I have suggested a "skos:notation" property, 
whose range would be typed literals [1]. I suggest typed (rather than 
just plain) literals because the datatype then defines the context in 
which the notation is uniquely identifying, i.e. you wouldn't get 
notation collisions. We ought to have an item on the SKOS proposals 
and issues page for notations - I'll do that asap.

Regarding the "size of a collection", you could first use the rule 
[(?x skos:subject ?y) (?y skos:broader ?z) -> (?x skos:subject ?z)] to 
construct a new graph, and then evaluate the following SPARQL query 
against the new graph:

SELECT ?x ?y WHERE { ?x skos:subject ?y }

For each distinct binding of ?y (i.e. for each concept), the number of 
result bindings in which that value occurs will give you the "size of 
the collection" for that concept.

Regarding the issue of "combinations" of concepts, there is an issue 
raised specifically for this problem [4]. I have written some rough 
notes at [2] and [3], that's as far as I've got :) There are some 
subtle issues involving when the order of coordination/combination 
is/is not significant, and how coordination/combination interacts with 
subject indexing. But supporting coordination/combination is 
definitely in scope for SKOS as far as I'm concerned.

Cheers,

Al.

[1] http://lists.w3.org/Archives/Public/public-esw-thes/2006Feb/0035
[2] http://isegserv.itd.rl.ac.uk/public/skos/press/dc2006/thesaurus.html
[3] 
http://isegserv.itd.rl.ac.uk/public/skos/press/dc2006/coordination.html
[4] http://www.w3.org/2004/02/skos/core/proposals#coordination-8

Jakob Voss wrote:
> Hi again,
> 
> Since nobody is awake and interested I try to answer the questions
> myself. I wrote:
> 
> 
>> 1. How to encode Notations
> 
> To encode a notation use xml:lang="alt".
> 
> The follwing examples states that there is a DDC number "030" for
> "General encyclopedic works":
> 
> <skos:Concept
> rdf:about="http://www.oclc.org/dewey/versions/ddc22print/#ddc030">
>   <skos:prefLabel xml:lang="art">030</skos:prefLabel>
>   <skos:prefLabel xml:lang="en">General encyclopedic works</skos:prefLabel>
> </skos:Concept>
> 
> Note that every concept can only have one preferred notation.
> 
> 
>> 2. How to get the size of a collection
>>
>> When browsing through a KOS you'd like to get the number of items that
>> are indexed with a concept (or with a concept and its subconcepts!). For
>> example see
>>
>> http://dmoz.org/Arts/Costumes/
>>
>> In this case the number of items in class Arts:Costumes (33) is shown,
>> but there are only 5 items that are directly indexed with Arts:Costumes
>> so you need a way to encode two numbers with a concept - any suggestions
>> who to do it in a consistent way?
> 
> This is a bit tricky because the number of records depends of the
> collection. So you cannot use a simple triple but a new Class is needed.
> I hereby introduce the Class "RecordNumber" for a number of records
> indexed by a Concept.
> 
> The follwing examples states that there are 2 works indexed with DDC
> number "030" in the cataloge of Common Library Service (GBV) and 13
> works indexed with any DDC number 030, and narrower numbers in the
> hierarchy:
> 
> <skos:Concept rdf:about="http://gso.gbv.de/DB=2.1/">
>   <skos:RecordNumber>
>     <skos:recordScheme rdf:resource="http://www.oclc.org/worldcat/"/>
>     <skos:recordNumber>2</skos:recordNumber>
>   </skos:RecordNumber>
>   <skos:RecordNumber>
>     <skos:recordScheme rdf:resource="http://www.oclc.org/worldcat/"/>
>     <skos:recordNumber>13</skos:recordNumber>
>     <skos:expandedRelation
> rdf:resource="http://www.w3.org/2004/02/skos/core#narrower">
>   </skos:RecordNumber>
> </skos:RecordNumber>
> 
> This includes 3 new relations:
> * skos:recordNumber
> * skos:recordScheme
> * expandedRelation
> 
> To only expand a specific distance you can also think of
> * skos:expandedDepth
> 
> Any suggestions?
> 
> 
> By the way to get the records try
> 
> http://gso.gbv.de/DB=2.1/SET=1/TTL=1/CMD?ACT=SRCHA&IKT=1016&SRT=YOP&TRM=ddc+030
> 
> and
> 
> http://gso.gbv.de/DB=2.1/LNG=DU/SRT=YOP/IMPLAND=Y/CMD?ACT=SRCHA&IKT=8562&TRM=030*
> 
> 
>> 3. How to encode concept combinations
>>
>> This is slightly complex but important. Maybe it can easily can be
>> solved with SKOS Mapping which I have not looked at enough. In some
>> thesauri you have non-prefered-terms and relations that point you to use
>> a concept in combination with another concept or vice versa to indicate
>> postcoordination or precoordination in indexing.
> 
> I think that relatedHasPart and relatedPartOf in
> http://www.w3.org/2004/02/skos/extensions is not what I meant.
> 
>> For instance the concept "Spanish town" could be defined as non-prefered
>> and point you to use the two concepts "Spain" and "town"
>> (post-coordination) or if you want to have "Spanish town" as a concept
>> for indexing (pre-coordination) then "Spain" and "town" both have a
>> special kind of associative relationship to "Spanish town".
>>
>> How should I encode this in SKOS?
> 
> Maybe you would answer to use SKOS mapping:
> 
> <skos:Concept>
>   <skos:prefLabel xml:lang="es">ciudad</skos:prefLabel>
>   <map:exactMatch>
>     <map:AND>
>       <map:memberList rdf:parseType="Collection">
>         <skosl:Concept>
>           <skos:prefLabel>Spain</skos:prefLabel>
>         </skos:Concept>
>         <skosl:Concept>
>           <skos:prefLabel>Town</skos:prefLabel>
>         </skos:Concept>
>       </map:memberList>
>     </map:AND>
>   </map:exactMatch>
> </skos:Concept>
> 
> But this is too complex. How about:
> 
> <skos:Concept rdf:about="#ciudad">
>   <skos:prefLabel xml:lang="es">ciudad</skos:prefLabel>
>   <skos:useCombination rdf:resource="#c1"/>
> </skos:Concept>
> 
> <skos:Combination rdf:about="#c1">
>   <skos:combinationMember rdf:resource='#spain'/>
>   <skos:combinationMember rdf:resource='#town'/>
> </skos:Combination>
> 
> <skos:Concept rdf:about="#spain">
>   <skos:prefLabel xml:lang="en">Spain</skos:prefLabel>
>   <skos:useInCombination rdf:resource='#c1'/>
> </skos:Concept>
> 
> <skos:Concept rdf:about="#town">
>   <skos:prefLabel xml:lang="en">Town</skos:prefLabel>
>   <skos:useInCombination rdf:resource='#c1'/>
> </skos:Concept>
> 
> Here I introduced the class Combination and the properties
> useCombination and useInCombination. So you can also add notes and
> documentation two Combinations if its a class.
> 
> Is anyone using SKOS Mapping in real life? It's just a theoretical
> sketch, isn't it? Is it used in any working information retrieval system?
> 
> Oh, I just found this thread about the same issue (but without a
> proposed solution?):
> http://lists.w3.org/Archives/Public/public-esw-thes/2006Jun/0006.html
> How about using the wiki instead so always have the latest version of a
> discussion?
> 
> Greetings,
> Jakob
> 
> P.S: Sorry for my cheeky comments - I just left university with a master
> in computer science and library and information science confronted now
> with the reality of standards and it's usage ;-)
> 
> 

-- 
Alistair Miles
Research Associate
CCLRC - Rutherford Appleton Laboratory
Building R1 Room 1.60
Fermi Avenue
Chilton
Didcot
Oxfordshire OX11 0QX
United Kingdom
Web: http://purl.org/net/aliman
Email: a.j.miles@rl.ac.uk
Tel: +44 (0)1235 445440
Received on Wednesday, 19 July 2006 14:20:04 UTC

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