Definitions

Hi team,

One of the problems with this are is that terms like schema and ontology are
used in multiple, conflicting ways. John and myself would look to propose
some specific terms in order to distinguish between these conflicting
definitions, but I'd be interested in comments on these definitions from the
team:

Instance data: Instance data is metadata that is specific to resources.

Schemas: Schemas are generic descriptions of collections of metadata. This
report proposes that it is possible to distinguish between four different
types of schemas: conceptual, ontological and constraint schemas and
controlled vocabularies. In the Semantic Web specific schema information,
possibly composed of all four types of schema, is identified using a
namespace. 

Conceptual schemas:  A conceptual schema defines a set of classes and
properties that can be used to describe a particular domain.

Ontological schemas: Ontological schemas describe relationships between
classes and properties, both within a namespace and between multiple
namespaces. 

Constraint schemas: A constraint schema describes constraints that are
applied to classes and properties. The main use of constraint schemas is to
validate metadata associated with a particular schema.

Controlled vocabularies: A controlled vocabulary defines a set of terms that
may be used as property values. The controlled vocabulary may optionally
define relations between the terms such as synonyms. 

Namespace: A namespace is grouping of related information that uses a common
name. A namespace may provide no information at all, but ideally it will
provide a conceptual schema, optionally supported by an ontological schema,
a constraint schema and optionally one or more controlled vocabularies. 

Application profile: An application profile is a conceptual schema derived
from subsets of several other conceptual schemas and associated with a
particular application. 

thanks in advance,

Dr Mark H. Butler
Research Scientist                HP Labs Bristol
mark-h_butler@hp.com
Internet: http://www-uk.hpl.hp.com/people/marbut/

Received on Thursday, 28 August 2003 06:45:48 UTC