@Article{RS93a, author = { Ronald L. Rivest and Robert E. Schapire }, title = { Inference of Finite Automata Using Homing Sequences }, journal = { Information and Computation }, publisher = { Academic Press }, issn = { 0890-5401 }, OPTyear = { 1993 }, OPTmonth = { April }, date = { 1993-04 }, volume = { 103 }, number = { 2 }, pages = { 299--347 }, doi = { 10.1006/inco.1993.1021 }, url = { http://www.sciencedirect.com/science/article/pii/S0890540183710217 }, abstract = { We present new algorithms for inferring an unknown finite-state automaton from its input/output behavior, even in the absence of a means of resetting the machine to a start state. A key technique used is inference of a homing sequence for the unknown automaton. Our inference procedures experiment with the unknown machine, and from time to time require a teacher to supply counterexamples to incorrect conjectures about the structure of the unknown automaton. In this setting, we describe a learning algorithm that, with probability $1 - \delta$, outputs a correct description of the unknown machine in time polynomial in the automaton's size, the length of the longest counterexample, and $\log(1/\delta)$. We present an analogous algorithm that makes use of a diversity-based representation of the finite-state system. Our algorithms are the first which are provably effective for these problems, in the absence of a ``reset.'' We also present probabilistic algorithms for permutation automata which do not require a teacher to supply counterexamples. For inferring a permutation automaton of diversity $D$, we improve the best previous time bound by roughly a factor of $D^3/\log D$. }, }