Information Technology Reference
In-Depth Information
transformation and the succeeding one supplements the result of the proceeding one.
Thus, an external plug-in for B
OCHICA
usually consists of (i) conceptual extensions and
(ii) an extension transformation for the required target environment (assuming that the
base transformation already exists). Maintaining the tool chain is one of the main prob-
lems in MDSD. Reusing existing model transformations reduces development costs and
time and increases code quality by using well established design patterns.
4.6
Custom Views and Tools
Views are used in graphical modeling languages to visualize the relations of model
artifacts of a certain sub-aspect of a system. B
OCHICA
provides standard views for
agent types and organizational structures, protocols, goal hierarchies, deployment con-
figurations, etc. 3rd party developers can use the extension interface for customizing
B
OCHICA
to a certain application domain or introduce new ways of viewing exist-
ing aspects. Views can also help to adapt the development environment to certain user
groups. Technically, diagrams and tools can be plugged into the framework by using
the extension point mechanism of the Eclipse OSGi framework and GMF
8
.
5
Evaluation
This section evaluates the B
OCHICA
framework in a complex real world case study.
As of today, intelligent behavior of avatars in virtual worlds is usually simulated by
triggered script sequences which create the illusion of intelligent behavior for the user.
However, the flexibility of those avatars is, due to their static nature, very limited. In the
research project
Intelligent Simulated Realities
(ISReal) our research group developed a
simulation platform based on semantic web technology for bringing intelligent behavior
into virtual worlds [11]. The basic idea of ISReal was to use semantic web technology
to extend purely geometric objects with ontological information (OWL-based; e.g. con-
cept door links two rooms and can be open or closed) and specify their functionality by
semantic service descriptions (OWL-S-based; e.g. open and close door services), called
object services
. Intelligent agents perceive this information, store it in their knowledge
base, and use it for reasoning and planning. An object service is grounded in a service
implementation which invokes according animations or simulation modules. The plat-
form consists of various simulation components which can be distributed in a network.
Before we discuss the B
OCHICA
extensions for developing intelligent ISReal avatars,
we introduce the main components of the ISReal platform.
Global Semantic Environment.
The
Global Semantic Environment
(GSE) maintains
the global ontological facts of the virtual world. It is responsible for (i) executing ob-
ject services (e.g. checking the pre-condition and invoking the service grounding), (ii)
updating facts (e.g. when a door gets closed), and (iii) handling queries (e.g. SPARQL).
Agent Environment.
The ISReal agent environment defines interfaces for connect-
ing 3rd party agent execution platforms to the ISReal platform (we currently use Jack,
