Which of the following is NOT a type of event in state machine modeling?

In state machine modeling, events are crucial as they trigger state transitions. The types of events generally recognized include signal events, call events, and change events. Each type serves a distinct purpose in how systems respond to various conditions.

Signal events are used to denote that a specific signal has been received, often from an external source, indicating that a state transition should occur. Call events occur when a call operation is invoked, allowing a transition based on a function call, typically associated with operations defined in the system. Change events trigger transitions based on changes in conditions or variables, often monitored during system operation.

Alert events, however, do not fit into this typical categorization of state machine events. While alerts might be associated with notifications within a system, they are not a formal type of event recognized in state machine modeling frameworks according to established standards. This distinction is why alert events can be identified as not being a type of event within this specific context.