What is NOT included among the Elements of Usage?

The Elements of Usage in the context of modeling typically refer to various components that describe how a model interacts with its environment or other models. Flow Ports, Call Behavior actions, and Object Nodes are all integral parts of this framework as they define how information moves through systems, how behaviors can be invoked, and how instances of objects are managed in the execution of a model.

Flow Ports serve as points of connection in models that facilitate data flow between components. Call Behavior actions are essential for invoking specific behaviors in the model's processes, allowing for dynamic interaction. Object Nodes represent instances of objects within activities, enabling the manipulation and processing of data and behaviors within the context of those activities.

Reference Properties, on the other hand, do not fit into the category of Elements of Usage as they are typically associated with defining relationships or attributes within the model rather than illustrating usage patterns or interaction flows. Thus, while important in a model, Reference Properties do not belong among the standard Elements of Usage typically referenced in modeling contexts.