Modeling Reactive Behavior in ORM Terry A. Halpin and Gerd Wagner   View Paper (PDF)   Return to Industrial Session II Abstract A system may exhibit proactive and reactive behavior. While proactive behavior is based on goal-directed action planning and execution, reactive behavior may be viewed as a set of reaction patterns that determine how the system reacts to events. Modeling reaction patterns is of particular importance for e-business systems, whose behavior is largely determined by their reactions to incoming messages. ©2005 Association for Computing Machinery