Modelling and Simulation of Asynchronous Real-Time Systems using Timed Rebeca

In this paper we propose an extension of the Rebeca language that can be used to model distributed and asynchronous systems with timing constraints. We provide the formal semantics of the language using Structural Operational Semantics, and show its expressiveness by means of examples. We developed a tool for automated translation from timed Rebeca to the Erlang language, which provides a first implementation of timed Rebeca. We can use the tool to set the parameters of timed Rebeca models, which represent the environment and component variables, and use McErlang to run multiple simulations for different settings. Timed Rebeca restricts the modeller to a pure asynchronous actor-based paradigm, where the structure of the model represents the service oriented architecture, while the computational model matches the network infrastructure. Simulation is shown to be an effective analysis support, specially where model checking faces almost immediate state explosion in an asynchronous setting.Comment: In Proceedings FOCLASA 2011, arXiv:1107.584

Partially distributed coordination with Reo and constraint automata

Algorithms and the Foundations of Software technolog

Compositional schedulability analysis of real-time actor-based systems

We present an extension of the actor model with real-time, including deadlines associated with messages, and explicit application-level scheduling policies, e.g.,"earliest deadline first" which can be associated with individual actors. Schedulability analysis in this setting amounts to checking whether, given a scheduling policy for each actor, every task is processed within its designated deadline. To check schedulability, we introduce a compositional automata-theoretic approach, based on maximal use of model checking combined with testing. Behavioral interfaces define what an actor expects from the environment, and the deadlines for messages given these assumptions. We use model checking to verify that actors match their behavioral interfaces. We extend timed automata refinement with the notion of deadlines and use it to define compatibility of actor environments with the behavioral interfaces. Model checking of compatibility is computationally hard, so we propose a special testing process. We show that the analyses are decidable and automate the process using the Uppaal model checke

Effective modeling of software architectural assemblies using Constraint Automata

Alfa is a framework for the construction of software architectures and their elements from architectural primitives. In any system involving events from multiple sources, synchrony and asynchrony between events arise naturally. Support for simultaneous synchrony and asynchrony, and scalability to assemblies of large numbers of architectural primitives are central concerns for effectively modeling software architectural assemblies in Alfa. An increasingly popular formalism for event-based modeling of the behavior of software architectures, labeled transition systems (LTS), was initially chosen to model the behavior of Alfa assemblies. However, this creates an impedance mismatch with the architect’s mental model and lacks sufficient scalability. We therefore propose a formal approach to effectively model software architectural assemblies that addresses these limitations, using constraint automata. Constraint automata can be mapped to LTS thus utilizing existing techniques for analysis of behavioral properties. We evaluate the effectiveness of our approach using two application architectures assembled from Alfa’s primitives

Process Algebraic Verification of SystemC Codes

SystemC is an IEEE standard system-level language used in hardware/software co-design and has been widely adopted in the industry. This paper describes a formal approach to verifying SystemC codes by providing a mapping to the process algebra mCRL2. The outstanding advantages of mCRL2 are the support for different data types and a powerful tool-set for model reduction and analysis. A tool is implemented to automatically perform the proposed mapping. This translation enabled us to exploit processalgebraic verification techniques to analyze a number of case-studies, including the formal analysis of a single-cycle and a pipelined MIPS processor specified in SystemC.

Sarir: A Rebeca to mCRL2 Translator

We describe a translation from Rebeca, an actorbased language, to mCRL2, a process algebra enhanced with data types. The main motivation is to exploit the verification tools and theories developed for mCRL2 in Rebeca. The mapping is applied to several case-studies including the tree identify phase of the IEEE 1394 standard. The results of the experiment show that the minimization tools of mCRL2 can be very effective and the outcome of the present translation outperforms that of the translation to the input language of the Spin modelchecker.