Subject languages part 2:

Structure

Structure of subject languages

• Alphabetical representation and classified representation.

• Synthetic structure and enumerative structure.

• Parallel hierarchies and facets.

Examples of alphabetic representation

ArchitectureArtBiologyChemistryEngineeringFine artsLife sciences

Architecture

BT Fine arts

NT Landscape architecture

Biology

BT Life sciences

NT Evolutionary biology, molecular biology

Example of classified representation

Arts and sciencesFine arts

Visual artArchitectureLandscape architectureMusic

SciencesLife sciences

Biology

New York Times information architecture

Examples of synthetic structureIn 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. An example from the 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.

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

Examples of parallel hierarchies

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

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

From the Eurovoc thesaurus, used to describe EU government documents:

Examples of facetsIn 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

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.

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?

Types of hierarchical relationshipsGenus-speciesFollow 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-partOften 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!

Examples of genus-species relationships

Single principle of division

Programming languages

Declarative languages

Functional languages

Imperative languages

Object-oriented languages

Procedural languages

Multiple principles of divisionPeople

(by family role)mothersfatherschildren

(by occupation)opera singersinformation professionalsmushroom hunters

A negative example

Unclear principles of division

Paintings

Portraits

Renaissance paintings

Oil paintings

Cave paintings

Impressionist paintings

Landscapes

Murals

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.)

A better examplePaintings

paintings by representational focus

PortraitsLandscape

paintings by styleRenaissance

paintingsImpressionist

paintingspaintings by materials used

Oil paintingspaintings by means of support

Cave paintingsMurals

These might be separate facets for a classification of paintings:

Representational focusStyleMaterialsMeans of support

Trees

According to Kwasnik, a tree is a looser form that shows a consistent principle of organization, but does not have the strict rules of inheritance and so forth that hierarchies have. Example:Grandparents

ParentsChildren

Examples of subject languages

• Warburg Institute classification.

• Alcohol and Other Drugs thesaurus.

Assignment components

• Introduction.• Classified representation. • Alphabetical representation. • Reflective essay.

Example: Garden decor

An excerpt of a classified structure for an “expressive gardening” classification that includes “garden decor” as a concept:Principles of garden expression

creativityunity

Means of garden expressionplant selectiongarden designgarden decor

Example: Garden decor

An excerpt of an alphabetical structure for an “expressive gardening” classification that includes “garden decor” as a concept:

garden decorbroader term: means of garden expressiondefinition: non-plant materials that add visual interest and, potentially, functionality(such as a place to sit) to the garden space. Benches, garden sculpture, and windchimes are all elements of garden decor. scope note: Documents that describe elements of garden decor, advise on their purchase, and explain their use should all be indexed with this term. Documents that describe the principles by which decor is selected and placed should be indexed under the principle. Non-plant materials that are used to facilitate plant growth or structure (such as arbors) are considered plant support, not decor.

Non-subject concepts

Don’t include document attributes that aren’t subjects, such as forms or genres (blogs, articles, books, diaries...).

You are creating a representation of a subject that can be used to organize documents; you are not describing the types of documents in which users might be interested.

Include in your classification: terms for concepts that relate to gardening, such as types of plants (grasses, cacti, shrubs).

Do not include in your classification: Document types that list such plants (plant databases, seed catalogs). However, you might use your classification to categorize a cactus database with the Cacti concept...

Sort like with like

Try to place like kinds of things together (processes, products, people), not just things that have some thematic relation. Remember, a hierarchy in its strict form takes one kind of thing and goes from the most general category to the most specific.

this: Animals -> domesticated animals -> animals raised for food -> pigs

this: Agricultural processes -> farming -> factory farming

this: Effects -> effects of farming practices -> effects on animals -> overcrowding

not this: Animals -> pastures, pens, cages -> overcrowding

not this: Animals -> factory farming -> mercury poisoning

Levels of abstractionWrangling your concepts can be difficult when they are at different levels of abstraction. You may need to generate intermediate levels that weren’t explicit in your source documents.

Source concepts: meat eating, e.coli, cholesterol, sustainabilitydisadvantages of meat eating

health risks

health risks associated with meat eating

high cholesterol

health risks associated with industrial meat production

bacterial contamination

e.coli contamination

unsustainable practices

effects of industrial meat production

consumption of resources

pollution

Node labels or subfacet labels

Especially because your classifications are small, many of you may make use of labels that help clarify the principles of division used in your classified structure.

In most cases, you will not use these terms to describe documents, and they are not, strictly speaking, actual concepts in your classification. You don’t need to include them in your alphabetical representation.

Example

Computers<by form factor>

DesktopLaptop

<by operating system>MacOSLinuxWindows

<by operating system> is just a structural label. It’s not a concept you’ll use to categorize documents.

Your continuing mission

• Continue compiling a list of potential concepts for your classification.

• Define an audience and purpose for your classification, and use this, as well as your subject knowledge, to more clearly define the scope of your classification, its boundaries and its central and peripheral areas.