Hybrid I/O automata

We propose a new hybrid I/O automaton model that is capable of describing both continuous and discrete behavior. The model, which extends the timed I/O automaton model of Lynch et al and the phase transition system models of Manna et al, allows communication among components using both shared variables and shared actions. The main contributions of this paper are: (1) the definition of hybrid I/O automata and of an implementation relation based on hybrid traces, (2) the definition of a simulation between hybrid I/O automata and a proof that existence of a simulation implies the implementation relation, (3) a definition of composition of hybrid I/O automata and a proof that it respects the implementation relation, and (4) a definition of receptiveness for hybrid I/O automata and a proof that, assuming certain compatibility conditions, receptiveness is preserved by composition

World Automata: a compositional approach to model implicit communication in hierarchical Hybrid Systems

We propose an extension of Hybrid I/O Automata (HIOAs) to model agent systems and their implicit communication through perturbation of the environment, like localization of objects or radio signals diffusion and detection. The new object, called World Automaton (WA), is built in such a way to preserve as much as possible of the compositional properties of HIOAs and its underlying theory. From the formal point of view we enrich classical HIOAs with a set of world variables whose values are functions both of time and space. World variables are treated similarly to local variables of HIOAs, except in parallel composition, where the perturbations produced by world variables are summed. In such way, we obtain a structure able to model both agents and environments, thus inducing a hierarchy in the model and leading to the introduction of a new operator. Indeed this operator, called inplacement, is needed to represent the possibility of an object (WA) of living inside another object/environment (WA)

Modelling Implicit Communication in Multi-Agent Systems with Hybrid Input/Output Automata

We propose an extension of Hybrid I/O Automata (HIOAs) to model agent systems and their implicit communication through perturbation of the environment, like localization of objects or radio signals diffusion and detection. To this end we decided to specialize some variables of the HIOAs whose values are functions both of time and space. We call them world variables. Basically they are treated similarly to the other variables of HIOAs, but they have the function of representing the interaction of each automaton with the surrounding environment, hence they can be output, input or internal variables. Since these special variables have the role of simulating implicit communication, their dynamics are specified both in time and space, because they model the perturbations induced by the agent to the environment, and the perturbations of the environment as perceived by the agent. Parallel composition of world variables is slightly different from parallel composition of the other variables, since their signals are summed. The theory is illustrated through a simple example of agents systems

Discrete Simulation of Behavioural Hybrid Process Calculus

Hybrid systems combine continuous-time and discrete behaviours. Simulation is one of the tools to obtain insight in dynamical systems behaviour. Simulation results provide information on performance of system and are helpful in detecting potential weaknesses and errors. Moreover, the results are handy in choosing adequate control strategies and parameters. In our contribution we report a work in progress, a technique for simulation of Behavioural Hybrid Process Calculus, an extension of process algebra that is suitable for the modelling and analysis of hybrid systems

Formal verification of Chi models using PHAVer

The hybrid Chi (x) language is a formalism for modeling, simulation and verification of hybrid systems. One of the most widely known hybrid system formalisms is that of hybrid automata. The formal translation of x to hybrid automata enables verification of x specifications using existing hybrid automata based veri??cation tools. In this paper, we describe the translation from x to hybrid automata, and the relation between hybrid automata and the linear hybrid I/O automata that are used for the verification tool PHAVer (Polyhedral Hybrid Automaton Verifyer). In the case study, we translate a x specification to a linear hybrid I/O automaton, and use PHAVer to verify properties