State identification problems for input/output transition systems

Abstract

A well-established theory exists for testing finite-state machines, in particular Moore and Mealy machines. A fundamental class of problems handled by this theory is state identification: we are given a machine with known state space and transition relation but unknown initial state, and we are asked to find experiments which permit to identify the initial or final state of the machine, called distinguishing and homing experiments, respectively. In this paper, we study state identification for input/output transition systems. An input/output transition system is a finite state machine each edge of which is labelled with either an input or an output action. We propose a method to transform such a system into a Mealy machine. By existing methods, we build an input/output experiment which is a solution for the identification problems for the obtained Mealy machine. A solution for the identification problems for the original system is then extracted.