1,001 research outputs found
Compatibility properties of synchronously and asynchronously communicating components
We study interacting components and their compatibility with respect to synchronous and asynchronous composition. The behavior of components is formalized by I/O-transition systems. Synchronous composition is based on simultaneous execution of shared output and input actions of two components while asynchronous composition uses unbounded FIFO-buffers for message transfer. In both contexts we study compatibility notions based on the idea that any output issued by one component should be accepted as an input by the other. We distinguish between strong and weak versions of compatibility, the latter allowing the execution of internal actions before a message is accepted. We consider open systems and study conditions under which (strong/weak) synchronous compatibility is sufficient and necessary to get (strong/weak) asynchronous compatibility. We show that these conditions characterize half-duplex systems. Then we focus on the verification of weak asynchronous compatibility for possibly non half-duplex systems and provide a decidable criterion that ensures weak asynchronous compatibility. We investigate conditions under which this criterion is complete, i.e. if it is not satisfied then the asynchronous system is not weakly asynchronously compatible. Finally, we discuss deadlock-freeness and investigate relationships between deadlock-freeness in the synchronous and in the asynchronous case
Interface Theories for (A)synchronously Communicating Modal I/O-Transition Systems
Interface specifications play an important role in component-based software
development. An interface theory is a formal framework supporting composition,
refinement and compatibility of interface specifications. We present different
interface theories which use modal I/O-transition systems as their underlying
domain for interface specifications: synchronous interface theories, which
employ a synchronous communication schema, as well as a novel interface theory
for asynchronous communication where components communicate via FIFO-buffers.Comment: In Proceedings FIT 2010, arXiv:1101.426
Connectors meet Choreographies
We present Cho-Reo-graphies (CR), a new language model that unites two
powerful programming paradigms for concurrent software based on communicating
processes: Choreographic Programming and Exogenous Coordination. In CR,
programmers specify the desired communications among processes using a
choreography, and define how communications should be concretely animated by
connectors given as constraint automata (e.g., synchronous barriers and
asynchronous multi-casts). CR is the first choreography calculus where
different communication semantics (determined by connectors) can be freely
mixed; since connectors are user-defined, CR also supports many communication
semantics that were previously unavailable for choreographies. We develop a
static analysis that guarantees that a choreography in CR and its user-defined
connectors are compatible, define a compiler from choreographies to a process
calculus based on connectors, and prove that compatibility guarantees
deadlock-freedom of the compiled process implementations
Model-Based Adaptation of Software Communicating via FIFO Buffers
Software Adaptation is a non-intrusive solution for composing black-box components or services (peers) whose individual functionality is as required for the new system, but that present interface mismatch, which leads to deadlock or other undesirable behaviour when combined. Adaptation techniques aim at automatically generating new components called adapters. All the interactions among peers pass through the adapter, which acts as an orchestrator and makes the involved peers work correctly together by compensating for mismatch. Most of the existing solutions in this field assume that peers interact synchronously using rendezvous communication. However, many application areas rely on asynchronous communication models where peers interact exchanging messages via buffers. Generating adapters in this context becomes a difficult problem because peers may exhibit cyclic behaviour, and their composition often results in infinite systems. In this paper, we present a method for automatically generating adapters in asynchronous environments where peers interact using FIFO buffers.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Soundness-preserving composition of synchronously and asynchronously interacting workflow net components
In this paper, we propose a compositional approach to construct formal models
of complex distributed systems with several synchronously and asynchronously
interacting components. A system model is obtained from a composition of
individual component models according to requirements on their interaction. We
represent component behavior using workflow nets - a class of Petri nets. We
propose a general approach to model and compose synchronously and
asynchronously interacting workflow nets. Through the use of Petri net
morphisms and their properties, we prove that this composition of workflow nets
preserves component correctness.Comment: Preprint of the paper submitted to "Fundamenta Informaticae
Stability-Based Adaptation of Asynchronously Communicating Software
International audienceSoftware Adaptation aims at composing incompatible black-box components or services (peers) whose individual functionality is as required for the new system. Adaptation techniques aim at automatically generating new components called adapters. An adapter works as an orchestrator and makes the involved peers work correctly together by receiving all messages exchanged in the system and by correcting mis-match between them. A challenging issue in this area is to consider that peers are described with (possibly cyclic) behavioural models and interact asynchronously, that is, exchanging messages via message buffers. The synthesis of adapters in this context is difficult because the composition of peers may result in infinite systems. In this paper, we propose new adaptation techniques, which rely on a property of communicating systems called stability. Stability aims at verifying whether a communicating system exhibits the same observational behaviour from a certain buffer bound on. We also provide adapter generation techniques using process algebra encodings and enumerative analysis techniques
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