HiLLS

HiLLS stands for High Level Language for System Specification, a graphical formalism that allows to describe the structure and behaviour of a system.
It is defined with the following elements M = < X, Y, Λ, Φ, Σ, Δ > where

The parameters actually define the context in which the system evolves, they are the information associated to the system and its environment. A phase is a set of states , grouped together according to a given subjective criterion. If we represent the system as an automaton, they are the nodes. In that case, Δ is the set of the edges of the automaton, they are called transitions.

Three phases and their associated transitions

Fig.1 - A simple example with 3 phases and 3 transitions.

A phase φ ∈ Φ can be written as φ = < invariant, activity, duration > where invariant characterizes what defines the phase, the state variables on the semantic domain (e.g. temperature, pressure, ...), activity is the result of a computation associated to the current phase, duration refers to the sojourn time of the phase that belongs to [0, +∞]. Any phase can be

Three phases

Fig.2 - The three differend kinds of phases: normal, passive and transient

A transition δ ∈ Δ is defined between two phases. Any transition can be

Three transitions Three transitions Three transitions

Fig.3 - The three differend kinds of transitions: internal, external and confluent