Automata, Computability and Complexity: Theory & Applications

Simulators and Graphical Interfaces for Finite State Machines
There exist many tools for working with FSMs. I’ve listed some of the ones I like best.

Finite State Transducers

Transition-Network Tools for Software Engineering

Markov Models

Hidden Markov Models (HMMs)

Büchi Automata and Other Automata on Infinite Strings