computer software engineer

Exercise A 1. The following statement describes a simple elevator/lift system: The elevator is moving between floors or is stationary at a floor. If the elevator is stationary then the brakes are applied. The brakes are not applied therefore the elevator is moving between floors i. Represent the above statement using state descriptions and the logically precise terms AND, OR, IMPLIES and NOT. Define propositions and logically portray the statement in Propositional Calculus Test the validity of the argument by constructing a truth table. 2. The lift/elevator system is composed of the usual arrangement of a lift cab moving in a lift shaft with entrances/exits to the lift cab at each floor level of the building. The lift controller interacts with other components in the following ways: Storing and responding to floor requests from users in the lift or at the lift doors on a particular floor. Controlling the speed of the lift engines to move the lift cabs up and down the lift shafts. Sounding alarm alerts to indicate trapped passengers or overloads. Processing load sensor data to ensure the load capacity of the lift cab is not exceeded 
beyond the safety limit. Processing information from position sensors to ascertain the current position of the lift, 
in the lift shaft, and its speed. Displaying current status information, of the lift, to passengers both within the lift cab 
and at each floor level adjacent to the lift. Controlling the door opening apparatus for allowing entrance and exit to the lift cab at 
appropriate times. 
Analyse some risks associated with the described system and model the operation of the elevator using propositions and predicates, indicating where your identified risks are addressed in the specification.