Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

PSL: A Semantic Domain for Flow Models



Conrad E. Bock, Michael Gruninger


Flow models underlie popular programming languages and many graphical behavior specification tools. However, their semantics is typically ambiguous, causing miscommunication between modelers and unexpected implementation results. This article introduces a way to disambiguate common flow modeling constructs, by expressing their semantics as constraints on runtime sequences of behavior execution. It also shows that reduced ambiguity enables more powerful modeling abstractions, such as partial behavior specifications. The runtime representation considered in this paper uses the Process Specification Language (PSL), which is defined in first-order logic, making it amenable to automated reasoning. The activity diagrams of the Unified Modeling Language are used for example flow models.
Software and Systems Modeling Journal


activity model, control flow, data flow, flow model, flow semantics, process specification, PSL, UML
Created May 1, 2005, Updated November 10, 2018