30 June 2005

Components of Ontology: More thoughts on Concepts

The different aspects of concepts (or perhaps, contributing concepts that combine to form higher order concepts) are known as the "properties" of the concepts.

Properties are very important, in that they are the aspect of the concept that allow different concepts to be grouped together. This ability to group together concepts is CRUCIAL for the formulation of rules (which provides for inference, and also the framework for relationships to exist within).

The existence of properties within concepts is also a key feature for the associated concepts, which are entities and relationships. Both of them are comprised of one or more concept, and those concepts have properties that allow them to be grouped together, and hence operated on by rules. Likewise, if our domain allows it (and the battlespace, which I am concerned with does), there can be categorical or "group" entities that are supersets of lower entities. Depending on the domain and it's own rules (and the nature of the relationships between entities and entity-sets) the properties of the entities might be inherited by the entity-sets.

An example seems like it will make this much clearer. For instance, in the battlespace domain, there is the entity of a Tank. This is (of course) an armoured vehicle that moves over land, has some defensive capability, a collection of engineering parameters, some offensive capability, and perhaps the capacity for crew members, supplies, and maybe the ability to tow or carry something. It is a fighting vehicle. In the ontology of the battlespace, it is an entity that falls somewhere under the entity "vehicle". Now there are also the entities within the battlespace of "armoured units", which are comprised of (among other things) "tanks". Some of the capabilities of tanks (derived from the concepts of the "tank") are going to be inherited by the entity "armoured unit". For instance, the maximum range with which an "armoured unit" can engage an enemy is based on the maximum range of the "tanks" that the "armoured unit" is a set of.

Likewise, not only entities but also relationships have concepts. These are a little more abstract than the concepts of entities, but only because we are not accustomed to thinking of them consciously. When we communicate, the rules of our language and semantics are definitely bounded by the concepts that comprise relationships. For an example, let us consider the binary relationship "tank has crew". There are two entities, tank (a subject entity) and crew (an object entity). These each have a number of concepts, some of which should be apparent.

But also consider the relationship "has". In this case, it is being used to define that an entity has as part of itself a number of other entities. To put it simply, think of it in terms of the set-entities that comprise both "tank" and "crew". This then becomes "vehicle has component", for a tank is a vehicle, and crew is a component of a vehicle.

At this point, "has" now has a few interesting concepts. First, it has a time subjectivity concept, by which I mean this - if we say a tank has crew, we mean two things. (1) A tank has the CAPACITY to contain 4 crew members (and needs 4 to function fully). (2) A tank has the POTENTIALITY of carrying 0,1,2,3 or 4 crew members subject to it's current state (is it in storage, is it in the field, has it been damaged, etc etc etc).

Second, the relationship "has" can imply the concept of specificity, semi-specificity (or class specificity), or non-specificity. By this I men that the tank can either (1) have SPECIFIC crew (Carol, Bob, Ted, and Alice), (2) have CLASS-SPECIFIC crew (gunner, loader, driver, commander), or (3) have NON_SPECIFIC crew (4 bodies). These are all concepts of the relationship, which allow it to be redefined, or to have its properties defined.

When looked at that way, the relationship "has" can be divided up into two more specific relationships of "has capacity of" and "has currently". Another aspect of the idea of "fractal ontology", where ideas can be re-represented at higher or lower orders of resolution. It can, of cource, be further divided up based on the specificity property.

Earlier concepts posting



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