2. In this assignment, you will model the behavior of the control system that lowers and raises the gate where a road crosses a railway. Road Near Far Far Near Train Passed Train Passed There are two sensors, e.g. Sensor One (left) and Sensor Two (right) respectively, telling the gate that a train is passed. This is a classical example of a real-time system, which we will only model very coarsely here, assuming that there is only a single track with only one train at a time and one gate in this assignment. However, a train could go in either direction. There are some specifications of the scenario following. When a sensor detects that a train passes, it will emit the signal "Train Passed" to the gate controller system, in order to make the gate start moving to the opposite direction to the previous one, e.g, from state up to state down We assume that the gate needs between 20 and 30 seconds to be lowered to go from the state up to the state down) or be raised (to go from the state down to the state up) or to come down The gate cannot be moved when the train is passing. Otherwise, it will lead to tragedy Your task is to: model the system by using correct UML notation. point out weaknesses of the system, and describe how the system could be improved to be more safe