  We consider the parameter synthesis problem of parametric timed automata
(PTAs). The problem is, given a PTA and a property, to compute the set of
valuations of the parameters under which the resulting timed automaton
satisfies the property. Such a set of parameter valuations is called a feasible
region for the PTA and the property. The problem is known undecidable in
general. This paper, however, presents our study on some decidable sub-classes
of PTAs and proposes efficient parameter synthesis algorithms for them.
