Applying blackboard techniques to real-time signal processing and multimedia network management

Two recent ORA projects have benefited from the AI principles captured in a blackboard design. DANA, a multimedia network monitoring system, has profited by using knowledge sources to implement a policy of guaranteed update consistency. Project X, a real-time passive radar system, has used knowledge source independence and the flexibility of opportunistic control to support easy experimentation with new system designs. Along with the benefits, we learned several lessons about the difficulties and pitfalls of blackboard systems. First, opportunistic control is hard to implement, maintain, and sell to managers. Second, knowledge sources are never as neat as they first appear. Finally, it is important to treat blackboards as a programming philosophy and not an architectural mandate