A Formal Method for Modeling, Verification and Synthesis of Embedded Reactive Systems

Embedded reactive systems are now invisible and everywhere, and are adopted, for instance, to monitor and control critical tasks in cars, airplanes, traffic, and industrial plants. However, the increasing amount of new functionalities being moved to software leads to difficulties in verifying the design correctness. In this context, we propose a novel design method called BARE Model, which is a formal abstraction to design, verify and synthesize software in embedded reactive applications. The method consists in designing the application using an extension of the well-known finite state machine, called X-machine. We thus propose to translate this model to a tabular data structure, which is a kind of state transition table augmented with memory input, memory output, and condition (or guard). This tabular structure may be automatically translated to the input of the NuSMV model checker in order to verify the system’s properties. We also propose a runtime environment to execute the system (expressed as a tabular data structure) in a specific platform. In this way, we can convert the high-level specification into executable code that runs on a target platform. To show the practical usability of our proposed method, we experimented it with the Envirotrack case study. The experiment shows that the proposed method is able to not only model the system, but also to verify safety and liveness properties, and synthesize executable code of real-world applications

Logic-Based Specification Languages for Intelligent Software Agents

The research field of Agent-Oriented Software Engineering (AOSE) aims to find abstractions, languages, methodologies and toolkits for modeling, verifying, validating and prototyping complex applications conceptualized as Multiagent Systems (MASs). A very lively research sub-field studies how formal methods can be used for AOSE. This paper presents a detailed survey of six logic-based executable agent specification languages that have been chosen for their potential to be integrated in our ARPEGGIO project, an open framework for specifying and prototyping a MAS. The six languages are ConGoLog, Agent-0, the IMPACT agent programming language, DyLog, Concurrent METATEM and Ehhf. For each executable language, the logic foundations are described and an example of use is shown. A comparison of the six languages and a survey of similar approaches complete the paper, together with considerations of the advantages of using logic-based languages in MAS modeling and prototyping.Comment: 67 pages, 1 table, 1 figure. Accepted for publication by the Journal "Theory and Practice of Logic Programming", volume 4, Maurice Bruynooghe Editor-in-Chie

Temporal Stream Logic: Synthesis beyond the Bools

Reactive systems that operate in environments with complex data, such as mobile apps or embedded controllers with many sensors, are difficult to synthesize. Synthesis tools usually fail for such systems because the state space resulting from the discretization of the data is too large. We introduce TSL, a new temporal logic that separates control and data. We provide a CEGAR-based synthesis approach for the construction of implementations that are guaranteed to satisfy a TSL specification for all possible instantiations of the data processing functions. TSL provides an attractive trade-off for synthesis. On the one hand, synthesis from TSL, unlike synthesis from standard temporal logics, is undecidable in general. On the other hand, however, synthesis from TSL is scalable, because it is independent of the complexity of the handled data. Among other benchmarks, we have successfully synthesized a music player Android app and a controller for an autonomous vehicle in the Open Race Car Simulator (TORCS.