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DigiCULT
of the elements and data types in the schema has
the prefix xs, which identifies them as belonging to
the vocabulary of the XML Schema language rather
than the vocabulary of our (fictitious) organisation
M-i.org.
(2b) Indicates that the elements defined by this
schema come from our http://www.m-i.org/images
namespace.
(2c) Is our default namespace.
(2d) Demands that any elements used by an XML
document which were declared in this schema must
be namespace qualified.
(3/16) The parent element for the data typing of the
image descriptions we provide at http://www.m-
i.org/images. It is (4) defined as a xs:complexType
,
i.e. it contains child elements (6-12), which are
(5/13) surrounded by an xs:sequence element that
defines an ordered sequence of these elements.
(6-12) The child elements, which in our example
are simple types because they do not contain other
elements.They define various elements of our XML
documents, e.g. "image", to be of the data type
xs:string.
(14) Furthermore, the Schema determines that for
the element xs:element name="image" there is a
required attribute "image_id" of the data
type="xs:string" (for example, image5kb78d38i).
Major Benefits of XML
In the context of the Semantic Web, XML provides
an interoperable syntactical foundation upon which
solutions to the issues of representing relationships
and meaning can be built.We also want to highlight
the many benefits of XML that are adding to its
rapid uptake in the first place, and might in the
longer term be supportive in realising the Semantic
Web vision on a broader scale.
XML is one of the most important standards
developments in recent years. It is an international,
universal, non-system and non-application specific
data exchange standard. XML is international,
because it employs Unicode.This means that there
is no restriction to the western alphabet, but Arabic,
Chinese, Greek, Hebrew,Thai, etc. can be easily
integrated.
XML is non-system specific, because it is an open
standard set by the World Wide Web Consortium
(W3C). As such, there is no owner of XML. All the
major software suppliers support it; it can be used on
any computing platform: from Windows and MacOS
to Linux.This makes it easier for organisations to
change systems or combine different systems.
XML is also non-application specific, i.e. it can be
used in various applications such as data exchange,
data harvesting,Web site management, etc. XML is
gaining ever-wider acceptance in many application
domains including, in particular, the cultural heritage
community.
Bear in mind also, that the major collection
management software producers have implemented
support for XML in their systems, enabling, for
example, the integration of data from different
collections and their combination over the Web.
XML allows for multi-channel publishing, i.e.
with XML it is easy to produce different products or
services from digital cultural heritage assets. Once the
data are structured in XML, they can be displayed
across a variety of media using an associated style
sheet that contains the display information.
Finally, XML can be used to create new languages.
For example, the Wireless Markup Language (WML),
which is used to markup Internet applications for
handheld devices, is written in XML.
Ontological concepts
The goal of the FMS project is to make metadata
of the museums' textiles collections semantically
interoperable on the Web. In order to achieve such
interoperability, an ontology is being designed that
describes the common (lower-level) ontological
concepts in this domain of knowledge.
4
Ontology
In the Semantic Web architecture, the semantic
relationships are not embedded but explicitly
represented by an ontology or, rather, an interrelated
set of ontologies. In fact, the wide array of informat-
ion residing on the Web and the perceived need to
make it more machine-processable have acted as a
strong impetus for the development of ontology
languages.
Yet, what is an ontology? An abstract definition
of an ontology is that it describes a formal, shared
conceptualisation of a particular domain of interest,
for example cultural heritage objects held in art
museums. In particular, an ontology allows for
constraining, expressing and analysing the intended
meaning of the shared vocabulary of concepts and
relations in a domain of knowledge.
5
If these concepts and relations are formalised to a
high degree, the domain has at hand a major building
block for developing semantically aware information
systems.With Semantic Web technologies, the
domain ontology can be made available on the
network, cross-referenced with upper-level and
4
The available documents (in
English) on the FMS initiative
state that their ontology is being
created using RDF Schema
(RDFS).To develop a fully
fledged ontology, advanced
languages such as DAML+OIL
or Web Ontology Language
(OWL) would be required.
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For more elaborate and formal
descriptions, see Tom Gruber:
What is an Ontology? (1995),
http://www-ksl.stanford.edu/
kst/what-is-an-ontology.html;
Nicola Guarino: Ontology-
Driven Conceptual Modelling,
part 1-3 (2002),
http://ontology.ip.rm.cnr.it/
Tutorials/