Systems Engineering Experience with UML on a Complex System

Presented at CSER 2005

Laurence Doyle and Michael Pennotti

Abstract: Experience using UML for systems engineering on a complex system is described.  The system was an experimental situation awareness system for small military units such as a hostage rescue mission. This experience provides insight into the use of process- oriented and object-oriented models. Real projects that experiment with methodology are an important source of information that cannot be duplicated on a contrived problem. 

Most of the functional requirements in this system involved software but there was also unique hardware. Use case specifications were derived directly from a very high level specification from the customer without any intervening artifact. Subsystem interaction diagrams were developed from the use case specifications. The use of UML as a systems design tool had the advantage that it greatly facilitated the transition into software development. 

While this approach was largely successful, there were some cases when the object-oriented model did not fit the problem. In addition to their role in task automation, models provide a mental representation that helps us solve engineering problems. Object- oriented and process oriented models provide two different representations. Because this project attempted to apply an object-oriented model so broadly, it was a de facto experiment in the use of such models. An examination of the cases where a process-oriented model fit better than object-oriented model provides insight into the differences between these two views.  The experience on this project supports the idea that  each view is a better cognitive fit to a different set of problems.

A link to the PDF paper:SE UML