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320 Semantic as an Interoperability Enabler in Internet of Things
exploit them useless, and some other services will be discovered,
activating applications already existing or downloading new ones.
Middleware should be designed properly to face this possibility and not
leaving the user with only a fixed set of applications available in just a
few places. Obviously, service discovery will become a major point in these
architectures.
Under these circumstances, middleware architectures with functionalities
beyond what is common have to be developed. Fortunately, semantics can be
used to upgrade the capabilities of middleware and match the requirements
that are expected from an Internet of Things deployment. In terms of information
technology, semantics can be defined as the capability of enhancing
data management and how data must be processed by means of information
inferring mechanisms from input data. By using semantic middleware architectures,
tasks as service discovery or device interoperability can be performed
in an easier and more efficient way, for semantics will offer tools able to cope
with the issues of the Internet of Things. To begin with, ontologies will be
provided. Although it is a term that is used in several fields, we will define
ontology as a group of terms that are typical of an area of knowledge, along
with the semantic relationships among these terms. Ontologies can be used to
solve the problem of scalability, as explained in Figure 9.2: if a new device
Fig. 9.2 Ontology usage example.