Re: Facet algebra

[!long text with examples, please skip if not interested in citation/filing
order
of facets in knowledge organization classifications]

Yannis,
I think this is a great work you've done.
I have had looks at the articles and I have the feeling that this
may be the answer but I need to spend more time on this to bridge
the gap between different perspectives in viewing facetted vocabulary.

When XFML was first published I found it too thin to support binding
of facetted vocabulary in a way that it is used for knowledge organization
(KO).
Now when I have my vocabulary in  a proper database I would like to
be able to do export in a more transportable format such as XFML
without loosing too much data. I will have look at XFML+

KO classifications I work on is based on the principles of facetted
(analytico synthetic
classification).
Vocabulary organized in facets contains subfacets and hierarchically
structured concepts
There are also facets that can be combined without limitations and facets
that have limited
area of application. Also the compound concepts themselves can be
synthesised using
relationship indicators (related to, influenced by, expanded with etc.) All
together there
are three levels of synthesis or compounds building.

The main goal of every knowledge classification is to be able to
display/present knowledge
from general to specific. Traditionally this is achieved through both the
definition of facets
and the rules these have to be combined and presented/filed.

Here is very simple example.

Literature is organized into main facet according to the language literature
is written in.
So I have  English, French, German literature (you can also call it the
facet of language
in the literature)
In the literature I also have three other facets that are applicable ONLY in
the field of
literature

facet of theory [criticism, stillistics, philological studies]
facet of time/period (old, middle, modern)
facet of genre (poetry, drama, fiction, esseys,correspondence etc.)

1) first level of synthesis (1st rule of combination)
Any concept in literure can be built using above mentioned facets
[English][Old][Poetry]
The order of these facets is usually defined by rule of combination that
will help achieving
general->specific presentation by the virtue of horizontally citing first
what is the most specific
to the subject, and last: what is the least specific to the subject.
So you cite first subject itself [English literature] then time facet [Old]
as it determines
the subject closer than the facet of form [genre]
Thus when filing these combinations you will have
[English][Old][Poetry]
[English][Old][Drama]
[English][Old][Fiction]
[English][Middle][Poetry]
[English][Middle][Drama]
[English][Middle][Fiction]
[English][Modern][Poetry]
and NOT
[English][Poetry][Old]
[English][Poetry][Middle]
[English][Poetry][Modern]
[English][Drama][Modern]etc.
Presentation of some disciplines and fields is not very much disturbed by
order of facets.
This is the case here. As it is well obvious, one may want to have different
order for different purpose
of gathering - but this  makes 'managing' of rules of combination even more
important
(for more intellectually demanding example see the following
http://www.ucl.ac.uk/fatks/religion.htm)

2nd level of synthesis

Every modren KO classification keeps generally applicable vocabularies such
as place, time, persons, languages
in a separate facets. For instance concept such as 'children' can be used
accross the knowledge structure
(Literature for children, games for children, children cloths, child
abuse).These facets have now limitation
of use and synthesis (almost), they can be combined among themselves and
with any subject concept.

These are for instance generally applicable facets

Facet of Persons (over 200 concepts) (e.g. see outline structure at
http://www.ucl.ac.uk/fatks/o_person.htm)
Facet of Place (over 700)
Facet of Time (over 700 concepts)
Facet of Form( over 400)
Facet of Language (over 1000)

(NB these facets have subfacets and hierarchically organized concepts as you
can see if you follow link
above)

When you have a subject which you want to specify further it works like
this:

			[persons]     [time]           [place]       [form]	[language]
English literature[for children][in 19th century][in Australia][study]  [in
French language]
Employment		[children]    [20th century]   [USA]	   [report] [in English
language]
----------->>>>>>----------decreasing
specificity---------------------------------->>>>

The way you order/cite these facets horizonatally is in decreasing
specificity/concretness
Explanation: while 'persons' very much define the subject as well as time,
the 'form' and the 'language' in which
the document is written, cited last, are the least relevant for the subject
itself.

When filing compound terms you have the reversed rule (of increasing
specificity):

English literature [in some language]
English literature [in some language][in some country]
English literature [in some country]
English literature [in some country][in some time]
English literature [in some country][in some time][for some kind of persons]
English literature [in some time]
English literature [in some time][in some country]
English literature [in some time][in some country][for some kind of persons]
English literature [for some kind of persons]


But there are situations in knowledge classification where some generally
applicable facet
is not to be used. For instance the part of facet of materials is irrelevant
for chemistry where
'materials' is the actual subject (e.g metals), or some part of facet of
'properties'(properties
of action and movement e.g. velocity, mass) is not relevant for physics.
These things are
usally documented in existing classification as instruction note, or
application which is a simple text.

3) 3rd level of synthesis

Is when you want to relate two or more distant subject facets (compound or
simple)with 'relators'

English literature <RELATION> Religion
English literature [in some country]<COMPARISON> French literature [in some
century]
Religion <INFLUENCE>English literature

Please not that classification uses notation (symbols) instead of the terms
I have used here
- and thus preserve the differnce between concepts and terms.

These bunch of rules makes the use of big knowledge classification harder to
grasp and
they are usually very poorly structured and harder to record, document and
exchange in machine
readable form.
Anyway if you look at the data model for faceted classification I am working
with
you may better understand the complexity of this
http://www.ucl.ac.uk/fatks/datastructure.doc

Do you think this can translate into XFML?

Aida

aida

-----Original Message-----
From: yannis_tzitzikas [mailto:[email protected]]
Sent: 03 September 2003 08:35
To: [email protected]
Subject: [facetedclassification] Re: Facet algebra


Dear Aida,

   My area is Computer Science and thus I am not very familiar with
the terminology used in library and information science. However I
would really like to know how people from your area view the Compound
Terms Composition Algebra.  I think that it would be much better if
you could accompany your question with some short examples (just for
avoiding misunderstandings).

What I can tell you from now is that the algebra indeed allows
expressing restrictions on synthesis. Concerning your question about
data encoding and classification exchange between different
applications, I have just defined XFML+ (an extension of XFML) which
allows representing and exchanging algebraic expressions as well.
Some information can be found in:
http://www.csi.forth.gr/~tzitzik/XFMLplus/

In addition, I would like to inform you that my Web page now contains
2 articles about the Compound Terms Composition Algebra:
(a) the one presented in EJC'2003 which gives all that one might want
for understanding the algebra,  and
(b) the one to be presented in ODBASE'2003 which describes the formal
semantics and explains why we cannot use the standard logic-based
formalisms (like Description Logics) for obtaining what we can  with
the Compound Terms Composition Algebra.

Regards,

Yannis

--- In [email protected], "Aida Slavic"
<aida@a...> wrote:
> Yannis,
>
> I need a bit of help in understanding the scope of 'compound terms
> composition algebra'.
>
> In managing facetted classification schemes there are three kind of
rules
> that needs to be encoded
> properly (apropriate data binding).
>
> -facet citation order rule (the order of facets in compound term to
achieve
> horizontal order with
> decending concretness)
> -filing order rules (the order compounds terms when they are filed
to
> achieve the hierarchy in
> knowledge display: general to specific)
> -restriction on synthesis and rules on combination between facets
> (the areas of application of certain facets)
>
> (NB I am not talking here about encoding semantic relationships
that are
> dealt with on the level of facet
> itself)
>
> While the first two rules are traditionally solved with
appropriate 'facet
> indicators' in classification notation,
> followed by appropriate data coding of this notation, the last one
needs a
> special attention.
> This is something that is usually  'handed over' to the application
or tool
> itself
> (program memory) and I have never seen it coded on the level of
> classification data.
>
> Am I right to think that 'compound terms composition algebra' takes
care
> about all of these rules?
> Does it provide solutions for data encoding as well (e.g. for the
the
> purpose of classification
> exchange and sharing between different applications).
>
>
> Aida
>



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