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8
DigiCULT
Genesis ­
The Creation:
Division of the
Waters Above
and Below the
Firmament
mute. By adding descriptive information to content
and resources, and representing both the descriptive
information and the content in well-defined,
consistent, and structured ways, `mechanised agents'
could be enabled to use web information `intelli-
gently'.Tim Berners-Lee, Jim Hendler and many
other researchers believe that commercial and public
sector institutions are increasingly recognising the
benefits of ensuring that their content is adequately
represented so that it is visible and discoverable
within the context of the Semantic Web.
The Semantic Web will enable the heritage sector
to make its information available in meaningful ways
to researchers, the general public, and even its own
curators.The public will be able to plan visits to
institutions by, for example, dynamically relating
opening times to public transport schedules. Use
information to discover whether or not that Vase in
the attic or basement is really Ming as their grand-
mother claimed by comparing it to the holdings of
heritage institutions across the world. Curators will
benefit from the ability to define an exhibition and
have the entire process from the identification of
the pieces to be shown in the exhibition to the
production of the catalogue and publicity material
automatically handled by their `exhibition agents'.
T
OWARDS AN
I
NTEROPERABLE
S
EMANTIC
W
EB FOR
H
ERITAGE
R
ESOURCES
D
elivering the Semantic Web to the heritage
sector depends upon (a) the syntactical and
semantic mark-up of content, (b) the development
of better knowledge analysis and modelling tools,
(c) widespread adoption of interoperable knowledge
representation languages, and (d) the construction of
suitable ontologies. In most of this the heritage sector
is lagging behind.We have not yet successfully repre-
sented sufficient quantities of our data in ways that
makes it accessible to human web users, let alone in
ways that would make it feasible for `mechanised
agents' to reason about in meaningful ways. `Languages
for representing data and knowledge are an important
aspect of the Semantic Web' (Klein, 2001: 26).The
languages that are currently the focus of the most
substantial discussion, such as the RDF, DAML+OIL,
and OWL
1
do not necessarily provide a suitable
framework for delivering the Semantic Web.This
point has been increasingly argued in the literature
although in practice we still tend to emphasise the
possibilities of representation mechanisms such as
RDF(S) because it provides a flexible and extensible
mechanism to represent metadata. A debate is raging
about which language should be used to represent
semantics on the web. Resource Description Frame-
work (RDF), an XML based mechanism for express-
ing metadata, has been put forward at the basic level,
but there is a growing body of opinion that indicates
it does not have the richness that is necessary to make
a suitable language. One of its shortcomings is that it
cannot support syntax. In response other languages
such as DAML+OIL have been developed. As an
indication of the current levels of flux, in a funda-
mental paper, Patel-Schneider and Siméon from Bell
Labs Research remark that `...there is a semantic
discontinuity at the very bottom of the Semantic Web,
interfering with the stated goal of the Semantic Web:
If Semantic languages do not respect World-Wide Web
data, then how can the Semantic Web be an extension
of the World-Wide Web at all?' (2002a, 147).
The strength of XML is that it does not, itself,
constrain how the data will be interpreted.While
XML does not imply a specific interpretation of the
data, how the material is marked up does constrain
how it can be used. Fallside (2001) has made plain
the weaknesses of using DTDs as a way of specifying
semantic properties in XML (eXtensible Markup
Language). XML Schemas offer a solution to these
weaknesses especially where those weaknesses arise
from representational problems. On the other hand
the hierarchical nature of XML does not fit all
domains, it `does not encode the data's use and
semantics' and DTDs and XML Schemas do not
specify the data's meaning although they do specify
the names of elements and attributes.Will the
Semantic Web produce different levels of sophis-
tication in the representation of data and knowledge
in the web-world? If it does will this create a patchy
representation of web information that will make
the Semantic Web of limited value?
1
See the `Semantic Web
Terms and Reading
List' in this Issue.