Running Scenarios

The syntactically right model accurately defines some system. Moreover, it might not be the system we had in mind. In reality, the system define might be seriously flawed – syntactic correctness does not guarantee correctness of behavior or function. The original goal of analyzing the model is to find out whether it truly describes the system which we want. The analysis should enable us to learn more about the model which has been constructed to examine how a system based on it would behave and to verify which it indeed meets expectations. This needs a modeling language with more than a formal syntax. It needs that the system used to create the model recognizes formal semantics as well.

If the model is based on a formal semantics system engineer can execute the model. The engineer can build and run a scenario which allows him to press buttons and observe behavior of the model previous the system is actually established. example For to exercise a model of an automated teller machine ATM the following steps happen:

(1) a conceptual model is established;

(2) the engineer plays the role of the bank computer  and customer, generating events like as insertion of a bank card buttons being pressed and new balance information arriving;

(3) the reaction of the system to these events is monitored

(4) inconsistencies in behavior are noted ;

(5) the conceptual model is modified to reflect proper behavior

(6) iteration occurs until the system which is desired evolves.

The system engineer runs views and scenarios the system’s response graphically. Active component of the model example for states in which the system is in at the moment and activities which are active are highlighted graphically and the dynamic execution results in an animated representation of the model. Execution of a scenario simulates the system running in real time and keeps the track of time-dependent data. At any point during the execution and the engineer can ask to see the status of any other, no graphical, element such as the value of a variable or a condition.