Terminology
From VoCamp Wiki
SPARQL Endpoint
RDF
- RDF stands for resource description framework
- RDF can be written using different serialization formats, e.g. RDF/XML, N3, RDFa
Triple Store
- Triple Store is a data store that stores triples.
- It can be implemented using DBMS or other technologies.
- Example triple stores: Mulgara, Talis, Jena, OpenLink, Virtuoso, AllegroGraph.
Triple
- A triple is a statement made up of subject, predicate and object
- If a node is a class or instance and a relation is a link, then a triple can be thought of as two nodes connected by a link.
- The relation in a triple is directional.
- Example triple: Austin is_a City.
RDF Triples
- RDF triples are triples in RDF format.
- RDF uses URIs to represent concepts (subjects, binary predicates, objects)
- RDF terms are one of these types: Class, Property (a.k.a. predicate), Instances
- geoNames:Austin rdf:Type openCyc:City
- Austin is an instance.
- Type is a Predicate.
- City is a class.
- Each term above refers to a URI.
Namespace
- A namespace is used as a shortcut for the base of a URI where a set of URIs are located.
- geoNames is an example of a namespace.
Vocabulary
- A flat list of terms.
- A vocabulary is comprised of a collection of URIs.
- Some people think of vocabulary as a collection of concepts.
- Some people think of a vocabulary as including facts that connect those concepts in order to at least partially define them.
- A vocabulary is a set of terms.
Taxonomy
- Terms connected in a hierarchy.
- Taxonomies use the relations subType and type.
Ontology
- Ontogies contain taxonomies.
- An ontology is a formalized representation of knowledge.
- An ontology can define and use a very rich set of relations (beyond subType and Type).
- An ontology can let you express facts about terms in the ontology and about the concepts that those terms refer to.
Inference
URI
- Universal Resource Identifier
- A URI defines a concept that should contain data which consitute facts about the concept
- As a convention of the Semantic Web, if you look up a URI, you will get either RDF or an HTML document, depending upon what you've "asked for". You say what you've "asked for" using content negotiation.
- People create URIs in a "place" that they have control over.
Relation
OWL
- OWL is written in RDF
- OWL has a richer semantics than RDF
Class
- A Class is description of things where there could be more than one of them in the world.
- Examples: Building, City, River.
- NOT Examples: Austin, TheEiffelTower, likes.
Property
- A property is the connector that relates the subject to something else.
- Examples: likesAsFriend, loves, containsInstancesOf.
- NOT Examples: Dog, Austin, Person.
- Property and predicate get confused with each other, because "predicate" has so many meanings.
Instance
- An instance is an individual thing.
- If Class is like a set, then an instance in an element in that set.
Linked Data
Linking Open Data
