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vanbeek:ejc96 [Wednesday, 19 March 2008 : 15:56:32] (current)
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 +===== A new mechanism for exception handling in concurrent control systems =====
 +//D.A. van Beek and J.E. Rooda//
 +The most difficult aspect of concurrent
 +discrete-event control is the handling of errors. Most present
 +day languages for concurrent control system specification do not
 +provide adequate mechanisms for exception handling, which is a
 +major limitation on their effectiveness. In this paper, a new
 +mechanism for exception handling in concurrently executing
 +discrete-event control processes is treated, which simplifies the
 +complex task of robust control system specification. The
 +mechanism is based on constraint monitors, and can be used in
 +conjunction with known mechanisms for exception handling in
 +sequential programs. Constraints and constraint monitors are new
 +concepts which are essential for dealing with exceptions in
 +control systems. The constraints of a statement are conditions
 +which must be valid throughout the execution of the statement.
 +Constraint monitors are used to specify the constraints of a
 +statement in a structured way, leading to programs in which the
 +code for normal operation is separated from the code for
 +exception handling. During the execution of the statement, the
 +specified constraints are monitored at all encountered
 +interaction points. If a constraint violation is detected, an
 +exception is raised. In this way, the invariants of a process
 +remain valid, finalization obligations of statements are
 +executed, deadlock in the case of exception occurrences is
 +prevented, and exceptions are not raised in processes in which no
 +constraints have been violated. Constraint monitors are explained
 +using a CSP-like language to which exception handling constructs
 +have been added. The constructs have been chosen in such a way,
 +that the resulting syntax and semantics are simple and especially
 +suitable for the specification of robust control systems. The
 +mechanism is finally illustrated by an example of the
 +specification of a control system.
 +//European Journal of Control//, vol. 2,no. 2, 88-100, 1996.
vanbeek/ejc96.txt · Last modified: Wednesday, 19 March 2008 : 15:56:32 (external edit)