Back-Propagation of Constraints from Consumer to Producer

In the context of distributed fusion systems, the communication between intelligent instruments, i.e. intelligent sensors and actuators, is the most important issue to deal with. The producer-consumer pattern is commonly used to facilitate the design of such systems. Then constraints based methods are commonly used to plan the data flow between instruments. The time consumption and the complexity of calculations associated to such methods avoid the possibility to react to the constraints changes. We propose to extend the producer-consumer approach to allow the consumer to define the constraints and to propagate these constraints to the producer that must adapts itself. This approach is a way to maintain the existing data flow structure and then avoid launching time-consuming calculus. The paper illustrates this proposal with the propagation of constraints on the refresh rate and on the confidence interval of data. A prototype is presented to illustrate and validate the approach on the OSGi platform.