A Control Model for Distributed Blackboard Architecture Based on Task Structures

Knowledge Based Real-Time Systems for intelligent patient monitoring must present the following characteristics: (a) reactivity and opportunism compatible with goal directed control, (b) domain independent task structures, (c) heterogeneous problemsolving methods, and (d) temporal reasoning. Conventional architectures present these characteristics in a separated way. To build a system that presents all these features, we propose a new architecture, the fractal blackboard architecture . Our proposal consists of a set of distributed blackboard systems organised in a hierarchical way. Each blackboard system is a specialist in charge of a specific domain task. In its more general form, each specialist consists of a control mechanism, a temporal blackboard, a blackboard interface (which include a temporal consistency maintenance system), a communication module and a set of subspecialists. So, the specialists can be recursively decomposed on other specialists with the same internal structure. We call agents to the terminal elements in this hierarchical structure. This decomposition makes possible to carry out a hierarchical planning of tasks in different abstraction levels. In order to achieve the features mentioned above, we must extend the basic control mechanism of the conventional blackboard architecture. In our model, a control mechanism is based on a library of domain-independent task structures. The knowledge necessary for task planning and reactive behaviour can be found in these task structures.