Q-Automata: Modelling the Resource Usage of Concurrent Components 1

Q–automata are introduced to model quality aspects of component-based software. We propose Q-algebras as a general framework that allows us to combine and choose between quality values. Such values are added to the transitions of automata, which represent components or channels. These automata can be composed by a product construction yielding a more complex Q-automaton labelled with the combined costs of its components. Thus we establish compositionality of quality of service based on an algebra of quality attributes associated with processes represented by automata.