Excerpts from Mikael's "DCAM 2.0" wiki page, January 2009...
This document defines the Dublin Core Abstract Model, which is the
model underlying the Dublin Core syntax specifications and Dublin Core
application profiles. The primary purpose of this document is to
specify the components and constructs used in Dublin Core metadata. It
defines the nature of the components used and describes how those
components are combined to create information structures. It provides
an information model which is independent of any particular encoding
syntax. Such an information model allows us to gain a better
understanding of the kinds of descriptions that we are encoding and
facilitates the development of better mappings and cross-syntax
This document is primarily aimed at the developers of software
applications that support Dublin Core metadata, people involved in
developing new syntax encoding guidelines for Dublin Core metadata and
people developing metadata application profiles based on DCMI
vocabularies or on other compatible vocabularies.
The Dublin Core Abstract Model builds on the structure and semantics of
the RDF conceptual model. It serves as a grounding of historical Dublin
Core grammatical principles in a formal specification.
The DCAM is defined as a set of abstractions on top of the RDF
conceptual model. For use independently of RDF, an abstract syntax is
The fundamental purpose of Dublin Core metadata is to describe things
in the world.
In the language of this document, a resource is anything in the world -
John Lennon, this document, the World Wide Web and the concept of love
are all resources.
Resources may be described by making statements. A statement says
something about a resource. "This document is created by Alistair
Miles", "Alistair Miles lives in the United Kingdom", and "the United
Kingdom is part of the European Union" are all examples of statements
that can be made using the DCMI abstract syntax.
The underlying abstraction of the Dublin Core Abstract Model therefore
builds on the notion of a subject resource and a value resource, and a
property to describe the relationship between the two.
A DCAM Syntax Encoding Scheme is a set of strings and an associated set
of rules that describe a mapping between that set of strings and a set
of resources. The mapping rules may define how the string is structured
(for example DCMI Box) or they may simply enumerate all the strings and
the corresponding resources. A syntax encoding scheme is the same as an
RDF data type.
A DCAM Vocabulary Encoding Scheme is an enumerated set of resources.
A DCAM Non-literal Value Surrogate consists of:
-- An RDF resource V (called the value RDF node)
-- An optional RDF triple
V dcam:memberOf VES
where VES is a URI of a DCAM Vocabulary encoding Scheme
-- Any number of triples of the form
V rdf:value LIT
where LIT is an RDF Literal
If V has a URI, the URI is called the DCAM Value URI.
LIT is called a DCAM Value String.
A DCAM Statement consists of:
-- An RDF triple
R property V
where the subject resource R is an RDF resource, and
-- if V is a non-literal RDF resource, a DCAM Non-literal Value
Surrogate, with V as the value RDF node.
A DCAM Description is a set of DCAM Statements with the same subject resource.
A DCAM Description Set is a set of DCAM Descriptions.
An abstract syntax for the abstract model
The following equivalent abstract syntax without reference to the RDF
model may also be used:
a DCAM Description Set is made up of one or more DCAM Descriptions
a DCAM Description is made up of
zero or one described resource URI and
one or more DCAM Statements
a DCAM Statement is made up of
one property URI and either
an RDF Literal, or
a DCAM Non-Literal Value Surrogate
a DCAM Non-Literal Value Surrogate is made up of
a reference to a separate DCAM description,
zero or one DCAM Value URIs
zero or one vocabulary encoding scheme URIs
zero or more DCAM Value Strings
The mapping to RDF triples is trivial based on the above definitions.
Literals and Non-Literals ...
Tom Baker <[log in to unmask]>