In: Advances in Computers, Vol. 45, Academic Press., pages 1-50. 1996.
Abstract: Information systems design has traditionally dealt with both data modeling and process modeling. Regarding process modeling, most design techniques based on structured design or object oriented design specify possible data flows and interactions among components, but are not very precise in specifying system control flow. On the other hand, the introduction of computer networks has enabled technologies like workflow automation and EDI to coordinate collaborative work in and across organizations, allowing process re-ingineering to shorted process times by introducing parallelism. The introduction of these technologies requires a precise specification of control for a parallel process. Moreover, process' specifiers are not necessarily computer scientists, nor are they willing or able to learn complex languages.
Several languages have been developed to specify control in workflow systems. Most languages specify control using diagrams similar both to traditional single-threaded control flow diagrams and CPM charts. These languages can represent both choice and parallelism. But this combination of language constructs, required for modeling processes, can introduce control anomalies, like useless work or even worse, deadlock. This paper is a first treatment of multi-threaded control flow in information processes. It presents common language constructs and some extensions, semantics, analysis methods, and a theory of threads of control which is used to analyze process models and to define the semantics for some of the language extensions. The formalization is given using Petri nets.
Keywords: workflow, control flow, behavior anomalies, control threads.