Subject Languages
Category structures
to represent topics
INF 384 C, Spring 2009
Outline
• Why? What are the goals of subject languages?
• What? What do subject languages look like?
• How? On what basis are subject languages
created?
INF 384 C, Spring 2009
Goals of subject languages
Ranganathan: To provide a helpful sequence of
documents, so that:
• Readers discover topics that may be useful.
• Books can display their potential to readers.
Svenonius: To improve collocation in retrieval; to
navigate the bibliographic universe; to represent
knowledge (as opposed to information).
INF 384 C, Spring 2009
Components of subject languages
Subject languages contain concepts represented
as terms.
The concept of “pH of water components of soil,
and the effects of this pH on the soil’s use in
supporting plant life,” may be represented as the
term “soil acidity.”
INF 384 C, Spring 2009
Structure of subject languages
• Alphabetical representation and classified
representation.
• Synthetic structure and enumerative structure.
• Parallel hierarchies and facets.
INF 384 C, Spring 2009
Examples of alphabetic representation
Architecture
Art
Biology
Chemistry
Engineering
Fine arts
Life sciences
INF 384 C, Spring 2009
Architecture
BT Fine arts
NT Landscape
architecture
Biology
BT Life sciences
NT Evolutionary
biology, molecular
biology
Example of classified representation
Arts and sciences
Fine arts
Visual art
Architecture
Landscape
architecture
Music
Sciences
Life sciences
Biology
INF 384 C, Spring 2009
New York Times
information
architecture
Examples of synthetic structure
In Ranganathan’s Colon Classification, subjects are constructed
by arranging concepts from the facets Personality, Matter,
Energy, Space, and Time (PMEST).
In the Dewey Decimal Classification, geographic information is
appended to a class name by means of standard tables. Topical
example from Dewey blog:
368.85400973 Bank deposit insurance—United States
The number is built with 368.854 plus 0 (extra 0 for standard subdivisions as
instructed in the add table under 368.1–368.8 Specific kinds of insurance) plus
T1—09 Geographic treatment plus T2—73 United States.
INF 384 C, Spring 2009
Example of enumerative structure
Warburg Institute classification: Image hierarchy
main classes
Primitive Art, Oriental Art, Classical Archaeology, Classical Topography,
Classical Iconography, Numismatics, Greek Art, Roman Art, History of Art,
Sources of the History of Art, Art Interpretation, Aesthetics, Topography,
Iconography, Survival Of Ancient Art, Early Christian & Byzantine Art,
Illuminated Manuscripts, Italian Art, Spanish Art, French Art, Flemish &
Dutch Art, British Art, German Art, Scandinavian Art, Applied Arts, Art
Collecting, 19th & 20th Century Art
INF 384 C, Spring 2009
Examples of parallel hierarchies
From the Eurovoc thesaurus, used to describe EU government
documents:
04 POLITICS
0406 political framework
0411 political party
0416 electoral procedure and voting
0421 parliament
0426 parliamentary proceedings
0431 politics and public safety
0436 executive power and public
service
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08 INTERNATIONAL RELATIONS
0806 international affairs
0811 cooperation policy
0816 international balance
0821 defence
10 EUROPEAN COMMUNITIES
1006 Community institutions and
European civil service
1011 European Union law
1016 European construction
1021 Community finance
Examples of facets
In the Bliss Bibliographic
Classification (BBC v.2), the
Human Biology and Medicine
field is organized into the
following facets:
• Types of persons
• Parts and systems of the person
• Processes in the person
• Actions on the person
• Agents of actions
INF 384 C, Spring 2009
A document whose subject is
nursing for children with cancer
would be described as:
(Type of person) Paediatrics (Processes) - Pathological Cancer - (Actions on) Nursing
Example from Bliss Classification Association:
http://www.blissclassification.org.uk/bchist.htm
Internal structure of subject
languages
• Hierarchical relationships.
• Equivalence relationships.
• Associative relationships.
INF 384 C, Spring 2009
Scope of hierarchical relationships
Universal hierarchies (mammal -> dog). Always true!
Perspective hierarchies (pet -> dog, or work animal ->
dog, or food -> dog). Only true under a certain point of
view or certain conditions.
Can a subject language ever attain universality?
INF 384 C, Spring 2009
Types of hierarchical relationships
Genus-species
Follow the all-some rule—X is a type of Y if all X’s are Y’s but only some Y’s are
X’s: all dogs are mammals but not all mammals are dogs. All the sibling concepts
should follow the same principle of division and be mutually exclusive, or multiple
principles of division should be elucidated through the structure.
Whole-part
Often treated as associative relationships in subject languages. A few exceptions:
• Systems and organs of the body
• Geographical locations
• Disciplines and subdisciplines
• Hierarchical social structures
Instance
Not types but instances: they involve proper names (Seas: Baltic Sea, Mediterranean
Sea). Not part of your subject language!
INF 384 C, Spring 2009
Examples of genus-species
relationships
Single principle of division
Programming languages
Declarative languages
Functional languages
Imperative languages
Object-oriented languages
Procedural languages
INF 384 C, Spring 2009
Multiple principles of division
People
(by family role)
mothers
fathers
children
(by occupation)
opera singers
information professionals
mushroom hunters
A negative example
Unclear principles of division
Paintings
Portraits
Renaissance paintings
Oil paintings
Cave paintings
Impressionist paintings
Landscapes
Murals
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These concepts do indeed
describe types of paintings, but
they represent multiple
perspectives on painting.
Mixing principles of division
like this makes the structure
difficult to understand and
browse. (If we did need to place
an item in one location, it would
be impossible, as well.)
Examples of subject languages
• Warburg Institute classification.
• Alcohol and Other Drugs thesaurus.
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Defining the scope of subject
languages
What marks the extent of a subject?
Should a classification of “information organization” as
a subject include information retrieval? Should it
include philosophy of language? Should it include
critical theory?
How does one make such decisions?
INF 384 C, Spring 2009
Rationale for including concepts in
subject languages
•
•
•
•
•
Literary warrant.
Use warrant.
Structural warrant.
Cultural warrant.
Others?
INF 384 C, Spring 2009
Example of structural warrant
From the MDA
Railway Object Name
thesaurus
INF 384 C, Spring 2009
<railways by means of propulsion>
<railways by power source>
<stationary traction source>
atmospheric railway
cable haulage railway
counterbalanced railway
water balance railway
rope haulage railway
gravity railway
<traction source moving with train>
animal powered railway
horse railway
locomotive railway
<self-propelled using externally supplied
power>
electric railway
Basic design process for subject
languages
• Define the subject. How? Do research. Define the
context. Think.
• Determine the concepts to include. How? Do
research. Consider the context. Think.
• Structure the concepts with hierarchical and
associative relationships. Add, delete, broaden, or
narrow concepts to balance the structure.
• Arrange the concepts at each hierarchical branch.
INF 384 C, Spring 2009
Your current mission
• Research the subject.
• Determine a purpose and audience for your
classification.
• Use the purpose and audience to define and
scope the subject.
• Collect concepts for potential inclusion.
INF 384 C, Spring 2009