Information Technology Reference
In-Depth Information
As the last step indicates, the entire process can be executed in an iterative
fashion. Instead of acquiring all potential findings, an initial set can be used
to derive an intermediate potential explanation that can then be used to guide
the next iteration of the process.
Service Discovery
The above is directly relevant because a scalable and workable approach to
service discover should follow the same pattern (see Fig. 9.3).
Fig. 9.3.
The three major processes in service discovery
Users may describe their desires in a very personalized and specific way
that makes immediate mapping to service descriptions very complicated.
Therefore, each attempt at service discovery requires a process where user
expectations are mapped to more generic goal descriptions. Note that this
can be hidden by the fact that a discovery engine allows the user to select
only from predefined goals. However, then it is simply the user who has to
provide this mapping, meaning that the user must translate his/her specific
requirements and expectations into more generic goal descriptions. This step
can be called goal discovery, i.e. the user or the discovery engine has to find
a goal that describes (with varying levels of accuracy) his/her requirements
and desires. In the current literature on service and Web service discovery,
this step is mostly neglected.
An example of such a user's desire (following the example of the VTA
presented in Section 9.1) would be to buy a train ticket from Innsbruck to
Vienna, to travel on December 12th 2004 with a departure time between 15:00
and 17:00. It can be seen that this is a very concrete and detailed desire, al-
though goals are typically intended to be generic and reusable. Therefore, a
mapping from the user's desire to a generic goal becomes necessary. In fact,
Web services are means to find (and buy) services. They are to a large extent
service discovery engines, and a discovery engine should not try to replace or
duplicate this functionality.
2
Web service discovery here is about searching
2
More precisely, Web services are an interface to a software artifact that may help
one to find and buy services (see [111]); however, we neglect this distinction here
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