An Interface Theory for Input/Output Automata

Building on the theory of interface automata by de Alfaro and Henzinger we design an interface language for Lynch's Input/Output Automata, a popular formalism used in the development of distributed asynchronous systems, not addressed by previous interface research. We introduce an explicit separation of assumptions from guarantees not yet seen in other behavioral interface theories. Moreover we derive the composition operator systematically and formally, guaranteeing that the resulting compositions are always the weakest in the sense of assumptions, and the strongest in the sense of guarantees. We also present a method for solving systems of relativized behavioral inequalities as used in our setup and draw a formal correspondence between our work and interface automata. Proofs are provided in an appendix

Color-blind specifications for transformations of reactive synchronous programs

Abstract. Execution environments are used as specifications for specialization of input-output programs in the derivation of product lines. These environments, formalized as color-blind I/O-alternating transition systems, are tolerant to mutations in a given program’s outputs. Execution environments enable new compiler optimizations, vastly exceeding usual reductions. We propose a notion of context-dependent refinement for I/O-alternating transition systems, which supports composition and hierarchical reuse. The framework is demonstrated by discussing adaptations to realistic design languages and by presenting an example of a product line.