The model multiplicity problem: Experimenting with real-time specificationmethods

The Object-Process Methodology (OPM) specifies both graphically and textual ly the system's static-structural and behavioral-procedural aspects through a single unifying model. This model singularity is contrasted with the mul timodel approach applied by existing object-oriented system analysis method s. These methods usually employ at least three distinct models for specifyi ng various system aspects-mainly structure, function, and behavior. Object Modeling Technique (OMT), the main ancestor of the Unified Modeling Languag e (UML), extended with Timed Statecharts, represents a family of such multi model object-oriented methods. Two major open questions related to model mu ltiplicity vs. model singularity have been 1) whether or not a single model , rather than a combination of several models, enables the synthesis of a b etter system specification and 2) which of the two alternative approaches y ields a specification that is easier to comprehend. In this study, we addre ss these questions through a double-blind controlled experiment. To obtain conclusive results, real-time systems, which exhibit a more complex dynamic behavior than nonreal-time systems were selected as the focus of the exper iment. We establish empirically that a single model methodology-OPM-is more effective than a multimodel one-OMT-in terms of synthesis. We pinpoint spe cific issues in which significant differences between the two methodologies were found. The specification comprehension results show that there were s ignificant differences between the two methods in specific issues.