A Subclass of Stream X machines with Underlying Distributed Grammars

The paper further investigates the properties of the stream X machines based on cooperating distributed grammar systems It is addres sed the case of regular components with various derivation modes and with derivation processes expressed by functions It is shown that in this case the translation power decreases but non context free languages still may be obtained from regular languages even for more restrictive mechanisms namely deterministic and output distinguishable devices When the deriva tion process leads to functions an upper limit of the number of derivation steps used by each component may be provided Some necessary conditions for transforming an Xmdg device for or a stream X machine into a cor responding deterministic one are also settled The speci cation of a smart card system illustrates that the concept is of practical interest too