1. From Objet Model to Dynamic Model: Still being at analysis and design level, when we have a Functional Model and the Object Model, then the next step is to further analyze and design the system iteratively, focusing on: When is an object initiated and when does it die? When do these objects interact with each other? . What messages do they send each other? In what sequence does this communication take place? What happens within an object when it is communicated with by some other object or external trigger