Employing disruptions for more efficient functionality decomposition in LOTOS

An improved functionality decomposition transformation for Basic LOTOS specifications is proposed which, given a specification of the required external behaviour (the expected service) of a system and a partitioning of the specified service actions among the system components, derives behaviour of individual system components implementing the service. There may be an arbitrary finite number of system components pairwise communicating by executing common actions and/or by exchanging messages over unbounded reliable first in first out channels. In comparison to previous similar algorithms, the transformation reduces inter component communication by selectively implementing synchronisation message receptions as disruptions of a recipient's inaction. The paper also identifies two flaws in the previous algorithms and provides means for their reparation.