Event Definition:
- An event is something that happens at a specific point in time. It’s like a message or notification from one thing to another.
- Events are quick, occurring instantly in the application’s timescale.
Types of Events:
A. Signal Event:
- What is it? It’s like sending or receiving a message (signal) between objects.
- Example: Think of a “TrainDeparture” signal with details like train, train number, city, and date.

B. Time Event:
- What is it? It happens at a specific time or after a certain time interval.
- Example: “when (date = January 1, 2020)” or “after (30 seconds)”.

C. Change Event:
- What is it? Triggered when a certain condition changes from false to true.
- Example: Events like “when (cabin temperature < heating set point)” or “when (temperature > cooling set point)”.
- Signal: Sending messages between objects.
- Time: Happens at a specific time or after an interval.
- Change: Triggered when a condition changes.
