20,872 research outputs found
Ten virtues of structured graphs
This paper extends the invited talk by the first author about the virtues
of structured graphs. The motivation behind the talk and this paper relies on our
experience on the development of ADR, a formal approach for the design of styleconformant,
reconfigurable software systems. ADR is based on hierarchical graphs
with interfaces and it has been conceived in the attempt of reconciling software architectures
and process calculi by means of graphical methods. We have tried to
write an ADR agnostic paper where we raise some drawbacks of flat, unstructured
graphs for the design and analysis of software systems and we argue that hierarchical,
structured graphs can alleviate such drawbacks
Constraint Design Rewriting
We propose an algebraic approach to the design and transformation of constraint networks, inspired by Architectural Design Rewriting. The approach can be understood as (i) an extension of ADR with constraints, and (ii) an application of ADR to the design of reconfigurable constraint networks. The main idea is to consider classes of constraint networks as algebras whose operators are used to denote constraint networks with terms. Constraint network transformations such as constraint propagations are specified with rewrite rules exploiting the network’s structure provided by terms
Exploiting Hierarchy in the Abstraction-Based Verification of Statecharts Using SMT Solvers
Statecharts are frequently used as a modeling formalism in the design of
state-based systems. Formal verification techniques are also often applied to
prove certain properties about the behavior of the system. One of the most
efficient techniques for formal verification is Counterexample-Guided
Abstraction Refinement (CEGAR), which reduces the complexity of systems by
automatically building and refining abstractions. In our paper we present a
novel adaptation of the CEGAR approach to hierarchical statechart models. First
we introduce an encoding of the statechart to logical formulas that preserves
information about the state hierarchy. Based on this encoding we propose
abstraction and refinement techniques that utilize the hierarchical structure
of statecharts and also handle variables in the model. The encoding allows us
to use SMT solvers for the systematic exploration and verification of the
abstract model, including also bounded model checking. We demonstrate the
applicability and efficiency of our abstraction techniques with measurements on
an industry-motivated example.Comment: In Proceedings FESCA 2017, arXiv:1703.0659
Supremica – An integrated environment for verification, synthesis and simulation of discrete event systems
An integrated environment, Supremica, for verification, synthesis and simulation of discrete event systems is presented. The basic model in Supremica is finite automata where the transitions have an associated event together with a guard condition and an action function that updates automata variables. Supremica uses two main approaches to handle large state-spaces. The first approach exploits modularity in order to divide the original problem into many smaller problems that together solve the original problem. The second approach uses an efficient data structure, a binary decision diagram, to symbolically represent the reachable states. Models in Supremica may be simulated in the environment. It is also possible to generate code that implements the behavior of the model using both the IEC 61131 and the IEC 61499 standard
Modelling and analyzing adaptive self-assembling strategies with Maude
Building adaptive systems with predictable emergent behavior is a challenging task and it is becoming a critical need. The research community has accepted the challenge by introducing approaches of various nature: from software architectures, to programming paradigms, to analysis techniques. We recently proposed a conceptual framework for adaptation centered around the role of control data. In this paper we show that it can be naturally realized in a reflective logical language like Maude by using the Reflective Russian Dolls model. Moreover, we exploit this model to specify, validate and analyse a prominent example of adaptive system: robot swarms equipped with self-assembly strategies. The analysis exploits the statistical model checker PVeStA
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