Introduction - Enabling Semantic Web Services: The Web Service Modeling Ontology - page 3

topic, [the Semantic Web] will make all the data in the world look like one
huge database” [12].
However, making the data on the Web machine-readable is still only half
of the story of revealing the full potential of the Web. Within conventional
databases, for example, machine-readable annotations usually adhere to com-
pletely different schemes and structures which remains the biggest obstacle
to automation of data integration tasks. The Semantic Web faces the same
problem.
Ontologies, which formally define the structure and meaning of machine-
readable metadata while simultaneously providing common, consensual meta-
data vocabularies to be used on the Semantic Web, will close this gap. To this
end, the W3C has developed metadata standards such as the Resource De-
scription Framework (RDF) and the Web Ontology Language (OWL). These
languages not only allow us to annotate the data on the Web in a machine-
understandable way but also enable additional inferences and allow for the
integration of this data via automated reasoning over its ontological struc-
ture.
Hovever, we are not at the end of the road, but it is only here where this
topic hooks in: the original idea of the Internet was about sharing not only
static data but also dynamic resources and services such as using procedures
and whole applications on remote machines. This idea is also starting to reveal
its full potential on the current Web. Humans interact with programs that
interact via Web interfaces in order to purchase topics, to book flights, to
check their current stock quotes, etc. in a much more dynamic fashion than
only sharing and requesting static data. Moreover, besides these business-
to-customer (B2C) services exposed as Web interfaces on the current Web,
there is an even stronger need for easy-to-use, easy-to-integrate services on
the business-to-business (B2B) level. In order to achieve full automation of
these services we must go beyond the universal database that the current
Semantic Web proposes. What we require is more like what could be called a
“service-oriented Semantic Web”.
The emerging Web service technologies are the first step in the direction
of such service-oriented architectures (SOAs). A unified protocol (SOAP), a
common interface description language (WSDL), the de facto standard of a
service registry (UDDI), and consistent use of a common XML-based syntax
provide the basic building blocks for such an infrastructure. Unfortunately,
even with such technologies, the integration of services still depends largely
on human experts. Web services as such are limited, in so far as they operate
on a merely syntactic level.
The proposed solution towards full automation of service usage, namely
facilitating the seamless integration of services that are published and acces-
sible on the Web, is called Semantic Web services [90]. Semantic Web services
are simply a semantic annotation of the functionalities and interfaces of Web
services. In the very same way that ontologies and metadata languages will
facilitate the integration of static data on the Web, the annotation of services