Semantic Annotation for Process Models: - Department of Computer ...

2.4. SEMANTIC INTEROPERABILITY 23
3. Structural conflicts. Such structural conflicts are different from structural heterogeneity.
Even if two modelers use the same data model, they can choose
different constructs to represent common real-world objects. For instance, in
object-oriented models when a modeler describes a component of an object type
O, he has the modeling choices between creating a new object type or adding an
attribute to O.
2.4.2 Semantic annotation
The goal of empowering computer systems with semantic interoperability rests on the
desirability of computer systems being able to find information and to use it for purposes
that the original creator of the information did not anticipate. This goal of flexible
information reuse requires some degree of understanding of the information, which
in turn requires that the information be encoded in some standard fashion that is
interpreted identically by all systems using that information. As a shared model of
what the information represent, ontologies are usually used to achieve the level of
understanding. Semantic annotation is an approach to link ontologies to the original
information sources.
Annotation is the extra information associated with a particular point in a document
or other piece of information. For semantic annotation, the extra information is
meaning definitions of the concepts used in a document. The meaning definitions are
in most cases represented in ontologies. Annotation can be in the form of comments,
or in the form of metadata. Metadata is data about data and it is used to facilitate the
understanding, use and management of data. Machine-manipulable annotations are
often organized as metadata, which is also the format of semantic annotations. There
are a number of alternative approaches regarding the organization, structuring, and
preservation of annotations. For instance, all the markup languages (HTML, SGML,
XML, etc.) can be considered schemas for embedded or in-line annotation. On the
contrary, open hypermedia systems use stand-off annotation models where annotations
are kept detached, i.e. non-embedded in the content. Both annotation approaches can
be document-level (annotating the document as a whole) or character-level (referring
just a specific part of the text) [81] (see Figure 2.4). Embedded annotation seems
easier to maintain. However, non-embedded annotations allow dynamic, user-specific
semantic annotations because they can change corresponding to the interest of the user
or the context of usage. The embedded annotations might also have negative impact
on the volume of the content and complicate the maintenance [70].
Figure 2.4: Embedded annotation and stand-off annotation [81]