Ontologies and Logic Graphs
What is an ontology?
An ontology is simply a structured way to represent information about a domain by defining its concepts, relations, rules and constraints. It enables machines and people alike to understand and interpret information in a streamlined manner.
In other words, an ontology is a formal and explicit manner of representing information in a shared specification of a domain. Hence, this makes an ontology a shared knowledge base.
In an ontology, you can represents relationships and concepts within a domain. Take for example a work environment where a person works for an employer.
What you see here is known as a triple, as to where there is a subject, predicate (to state if the preposition is true or false) and an object (entity that is being referred to in order to create the relationship).
Upper Ontologies and Domain Ontologies
An upper ontology is basically a domain of shared information that covers vast and broad concepts whereas a domain ontology is more specific to a certain domain. Furthermore, upper ontologies are limited to high level concepts whereas domain ontologies are built on specializing and extending upper ontologies
An upper ontology is simply a higher level domain that covers a broad array of concepts whereas a simple domain ontology is more specific to a domain, hence enhancing a upper domain ontologies concepts range.
Take for example a car and an person as an subject and object in an RDF triple. Here a car has a person to drive it, this is an instance on an upper ontology where the concepts for the person entity are relatively broad. The concept can further be enhanced through the use of domain ontologies.
To conclude, an domain ontology enhances and upper level ontology by adding new concepts to enhance a currently existing concept.
What is a taxonomy?
A taxonomy is basically a hierarchical classification system that organizes concepts or entities into groups and/or sup categories, similar to a tree structure
In other words, a taxonomy simply represents a hierarchy of information to represent an ontology. This is where the concept of upper ontologies and domain ontologies comes into consideration.