The net-centric ISR/ISTAR networks are expected to play a crucial role in the success of critical tasks such as
base perimeter protection, border patrol and so on. To accomplish these tasks in an effective and expedient
manner, it is important that these networks have the embedded capabilities to discover, delegate, and gather
relevant information in a timely and robust manner. In this paper, we present a system architecture and an
implementation that combines a service based reasoning mechanism with a sensor middleware infrastructure so
that tasks can be executed efficiently and effectively. A knowledge base, utilising the Semantic Web technologies,
provides the foundation for reasoning mechanism that assists users to discover, identify and allocate resources
that are made available through the middleware, in order to satisfy the needs of tasks. Once resources are
allocated to any given task, they can be accessed, controlled, shared, and their data feeds consumed through the
Fabric middleware. We use the semantic descriptions from the knowledge base to annotate the resources (types,
capabilities, etc.) in the sensor middleware so that they can be retrieved for reasoning during the discovery and
identification phases. The reasoner is implemented as a HTTP web service, with the following characteristics:
1. Computational intensive operations are off-loaded to dedicated nodes, preserving the resources in the
2. HTTP services are accessible through a standard set of APIs irrespective of the reasoner technology used.
3. Support for seamless integration of different reasoners into the system.