Home » Projects » AI-Trader » Conceptual Graphs
With the emergence of high level services as found
in the World Wide Web the need for an appropriate typing mechanism
becomes evident. An application user (i.e. not a programmer)
must deal with service types to lookup matching service providers. So
far there exist only simple keyword based traders which allow only for
a limited expressiveness of service types. We have chosen to develop a
type specification based on conceptual graphs which are
particularly useful to support the cognitive domain of the users.
Conceptual graphs have been developed to model the
semantics of natural language. Service descriptions based on
conceptual graphs are therefore intuitive in the sense that there is a
close relationship to the way human beings represent and organize
their knowledge. From an abstract point of view a conceptual graph is
a finite, connected, directed, bipartite graph. The nodes of the graph
are either concept or relation nodes. Due to the
bipartite nature of the graphs, two concept nodes may only be
connected via a relation node.
A concept node represents either a concrete or an
abstract object in the world of discourse. As for the context of
service types a concept may be a concrete object such as
including specific instances (e.g.
Ingres, etc), as well as an abstract
object such as
PROGRAMMING-LANGUAGE with no physical representation.
Whereas concepts model objects of our perception, a relation node
expresses a specific relationship between concept nodes.
The following conceptual graph describes a
vacation (concept nodes are surrounded by square brackets and
relations by round brackets, respectively). The informal semantic of
the concept is: A vacation in a city. During the vacation are
cultural activities as concert and sightseeing offered. The duration
of the vacation is 7 days.
Figure: Conceptual Graph describing the concept vacation
Within the AI-Trader Project we have developed a
trader capable of processing service descriptions based on conceptual
graphs. The implementation
(including the complete sources) are freely available. A Java-ased
frontend makes editing of conceptual graphs easy (the screenshot above
came from this frontend). Some publications describe the philosophy
behind the AI-Trader.