Databases Reference
In-Depth Information
OntoWiki enables the easy creation of highly structured content by distributed commu-
nities. The following points summarize some limitations and weaknesses of OntoWiki
and thus characterize the application domain:
Environment
:
OntoWiki is a Web application and presumes all collaborators to work
in a Web environment, possibly distributed.
Usage Scenario
:
OntoWiki focuses on knowledge engineering projects where a single,
precise usage scenario is either initially (yet) unknown or not (easily) definable.
Reasoning
:
Application of reasoning services was (initially) not the primary focus.
4.2
Generic and Domain-Specific Views
OntoWiki can be used as a tool for presenting, authoring and managing knowledge
bases adhering to the RDF data model. As such, it provides generic methods and views,
independent of the domain concerned. Two generic views included in OntoWiki are the
resource view and the list view. While the former is generally used for displaying all
known information about a resource, the latter can present a set of resources, typically
instances of a certain concept. That concept must not necessarily be explicitly defined as
rdfs:Class or owl:Class in the knowledge base. Via its faceted browsing, OntoWiki
allows the construction of complex concept definitions, with a pre-defined class as a
starting point by means of property value restrictions. These two views are su
cient for
browsing and editing all information contained in a knowledge base in a generic way.
For domain-specific use cases, OntoWiki provides an easy-to-use extension interface
that enables the integration of custom components. By providing such a custom view, it
is even possible to hide completely the fact that an RDF knowledge base is worked on.
This permits OntoWiki to be used as a data-entry frontend for users with a less profound
knowledge of Semantic Web technologies.
4.3
Workflow
With the use of RDFS [27] and OWL [126] as ontology languages, resource defini-
tion is divisible into di
erent layers: a terminology box for conceptual information
(i. e. classes and properties) and an assertion box for entities using the concepts defined
(i. e. instances). There are characteristics of RDF which, for end users, are not easy to
comprehend (e. g.
classes
can be defined as
instances
of owl:Class). OntoWiki's user
interface, therefore, provides elements for these two layers, simultaneously increasing
usability and improving a user's comprehension for the structure of the data. After start-
ing and logging in into OntoWiki with registered user credentials, it is possible to select
one of the existing ontologies. The user is then presented with general information about
the ontology (i. e. all statements expressed about the knowledge base as a resource) and
a list of defined classes, as part of the conceptual layer.
After starting and logging in into OntoWiki with registered user credentials, it is
possible to select one of the existing knowledge bases. The user is then presented with
general information about the ontology (i. e. all statements expressed about the knowl-
edge base as a resource) and a list of defined classes, as part of the conceptual layer. By
selecting one of these classes, the user obtains a list of the class' instances. OntoWiki
ff
