Adding file

Vocabulary-properties-and-ontologies.md

+
+### Introduction
+
+
+There are two related yet distinct issues: controlled vocabularies and ontologies. The vocabularies are a list
+of properties and can easily be accommodated in a single SQL table. Policies need to be developed for create,
+update, and delete of property entries. It might also be sensible to design the properties with multilingual
+labels, that is multiple labels where each label is specific to a specified language. All properties for all
+vocabularies are (probably) equivalent, thus there is only a single extensive list of properties. Each
+property has a unique id, and needs a definition. By and large, the property table is simply a dictionary-like
+entity with labels and definitions.
+
+### Property domain
+
+By design properties have a domain which is made explicit by the definition. The Wikipedia clarifies this
+issue since some terms only result in a disambiguation page. My "automotive" example may not be good, but the
+"belt" example holds up quite well.
+
+
+"Automotive" defined as "related to automobiles" includes "automobile" and therefore has a broad domain. There
+might be no property "automobile". We need a policy for properties, but I'm fairly sure that a property should
+be a broad as possible without being ambiguous, and narrowing is handled by ontology and multiple
+properties. "Seat belts" are "webbing designed to retain an occupant or object in a seat". There is no
+single property "Automotive--Seat belts", but the separate ability to create complex lists and ontological
+entries allows for "Automotive" + "Seat belt", as well as "Roller coaster" + "Seat belt" and "Aircraft" +
+"Seat belt".
+
+The curatorial question: Is a seat belt simply a complex list of "belt" and "seat". I think not. The word
+"belt" is (in English) applied to clothing, machinery belts, and webbing. Arguably, "seat belt" is simply
+Enlish-centric, where the word "belt" has multiple different meanings some of which could just as well be rope
+or chain. Perhaps the guiding curatorial policy is "avoid confusion" while attempting to be broad. Properties
+which might naturally have multiple meanings should be avoided. Thus, we avoid the property "belt", which
+isn't so much broadly inclusive as it is describing mutually exclusive things. The word "automotive" is broad
+and inclusive. Thus properties for "belt (mechanical)", "seat belt", "belt (clothing)" make sense. The
+definitions would be explicit, and adding "(clothing)" merely disambiguates the label.
+
+In Spanish, a "fan belt" is "correa del ventilador", not "cinturon del ventilador". The Spanish word
+"cinturon" is a clothing belt. This difference between languages clarifies what are properties, and what words
+are simply conflations specific to English (or any language). My translations may be a bit clumsy, so I hope
+the conclusion is clear:
+
+```
+cinturon == belt (clothing)
+correa de transmisión == belt (mechanical)
+```
+
+Even Spanish has issues with belt. The word "correa" by itself is "strap". 
+
+
+It is reasonable to have a property "airplane" as well as "aircraft"? Perhaps, and there is some burden on
+archivists to choose "jet (aircraft)" + "seat belt" when speaking of a Boeing 747, and "Aircraft" + "Glider" +
+"Seat belt" when refering to a glider, although I'm not convinced that glider seat belts adds useful facets of
+information. 
+
+The ontology needs to clarify sub-classes where "jet (aircraft)" and "glider" are more specific
+examples of "Aircraft". In fact, using a broad category is superfluous when the narrow property is supplied.
+
+It would be just as useful to search/analaysis to have a separate topical subject "gliders". In fact, from a
+computational point of view, there is probably no difference between complex lists of topical subjects and
+lists of singleton topical subjects. These are equivalent:
+
+```
+subject: Aircraft
+subject: Seat belts
+subject: Gliders (aircraft)
+```
+```
+subject: Aircraft + Seat belts + Gliders (aircraft)
+```
+
+In fact, the first example is more clear and easier to analyze. If this is true, then we could apply a
+universal rule: There are no complex properties, although multiple properties are allowed (and encouraged)
+
+
+Properties are not themselves complex. "Automotive" is broad, and if the added specificity of "parts" is
+desired then a second topic "Parts" (Parts: components of a large entity) needs to be used. Component lists
+are in the domain of ontologies, not properties. There is no single property "Automotive--Parts", or
+"Automotive--Paintings", and this needs to be enforced by database design, user interface and policy.
+
+### Proper entities are not properties. 
+
+
+The ontology linkage handles issues such as "Automobiles" +
+"Detroit". There is no property "Detroit", although there is a CPF entity for "Detroit, MI USA". It is
+possible to conflate CPF entities in the user interface to enable the construction of a topical subject
+"Automobiles" + "Detroit". 
+
+Consider what happens if (and I'm opposed to this) all CPF entities were imported into the property
+table. That would be denormalization and data duplication, and will only end in tears. 
+
+### Ontologies use the properties, but are a separate problem. 
+
+The ontology should have publishers of Automotive + Paintings. Graphic materials ontology should include
+Automotive + Paintings. The underlying properties are the same in both branches of the ontology, but the
+ontological relationship is quite different because one is sub-category of "Publishers" and the other of
+"Objects".
+
+The ontology system deals with sub-classes as the example where "Jet (aircraft)" and "Glider" are more specific
+examples of "Aircraft". 
+
+### Ontology and property interact to create search facets
+
+A search for "Aircraft" should turn up "Glider (aircraft)" even if the record in question lacks "Aircraft" as
+a specific topical subject. In general, a search for a parent property should include all child properties as
+specified by the ontology. Searching for the Spanish term "Ropa" will include "Cinturon" which has the English
+label "Belt (clothing)".