Using the requirements gathering techniques of document review, observation, brainstorming, sampling and research to capture the requirements of a typical elevator control system. Use natural language and the UML (see the notes/textbook chapter for section on Use Case Diagrams and Sequence Diagrams) to represent the situation where people on different floors push the "Up" button at the same time. Use a drawing tool like Microsoft Word Shapes, or http://draw.io (Links to an external site.) to diagram your solution. Be sure to explain your answer.
1b. Complete the same but with the situation where a person pushes the button "UP" but the elevator is stuck or not working.