Realtime System Control by means of Path Expressions

This paper treats a high-level, algebraic programming method for the on-line control of actions in a realtime, parallel processing environment. The method is based on interaction of path expressions. On the basis of a set of path expressions evocation of actions can be controlled in realtime in a fully automated way. It is shown how intelligent system behaviour can be obtained by a combination of rules given as path expressions. Each of these rules specifies some partial behaviour to which the system must comply. The control system operates as a rule-based action planning system that works on-line in an asynchronous environment. 11. PATH EXPRESSION CONSTRUCTS The basic path expressions constructs that we will consider are: sequential composition (using the sequence operator ’;’) parallel composition (using the parallel operator ’&) altemative composition (using the choice operator ’,’). Extended path expression constructs are the combinatory composition or intersection (using the operator ’*’) and repetitive forms of compositions as shown in table 1.