Posted on Sep 20, 2002

David
Hannay, professor
of computer science, is to publish a paper, “Interactive Theory,” in
the December issue of Inroads-The SIGCSE
Bulletin, (Vol. 34 No.4) the Computer Science Education journal of the
Association for Computing Machinery. The web-based simulations encompass the
six core abstract models of computation: finite-state, pushdown and Turing
machines as well as regular expressions, context-free grammars, and recursive
functions. All six simulations come packaged with predefined
machines/expressions/grammars/functions. Users can also create
machines/expressions/grammars/functions from scratch. Each of the machine
simulations traces arbitrary input as processed by the machine. The regular
expression simulator tests if an entered list of words are part of the language
of a regular expression, and generates random words represented by an
expression. The context-free grammar simulator also generates words in the
corresponding language. Finally, the evaluation of functions can be traced to a
user-specified depth of recursion. The simulators can be accessed at http://cs.union.edu/~hannayd/csc140/simulators.