Module 3: Requirements Engineering (Part 2)

In module 3 part1, we already talk more theory about requirements engineering. So, in this part we will focus more about the guidelines of creating requirements analysis model. We have been explained about use case diagram, activity diagram, state diagram, and sequence diagram in previous class. But, what we need to know in details is how to implement use case diagram if any situation is given. 

Basically, requirements or analysis model is a graphical representations of business processes, the problems to be solved, and the new proposed product (software).

There are a  lot of principles in requirements modelling. The principles are:

• Principle1: the information domain of a problem mustbe represented and understood.
• Princple2: The functions must be defined.
• Principle3: The behavior of the software must be represented.
• Principle4: The models that describe information, function and behavior must be partitioned in manner.
• Principle5: The analysis task should move from essential information toward implementation detail. 

Rules of thumb.

A rule of thumb is a principle with applications that is not intended to be strictlyor reliable for every situations. it is an easily appliedprocedure for approximately calculating or recalling some value or for making some determination. 

In this chapter also, Pn. Badariah already talk about two main levels in analysis modelling. Both levels are:

• Context Modelling : Context modelling is a divide and conqure method based on separations into sub         data by context, so that each sub data can be approximated with a simple mode.Technical modelling:
• Technical Modelling.

Technical Modelling.

2 approaches for this modelling.

1. Structured analysis
2. Object oriented analysis.(OO Analysis) 

We as student needs to understand OO analysis. OO modelling has 3 elements which is:

• Scenario-based
• Class-based
• Behavioral

We need to know the basic of this 3 elements. But need to focus more in Scenario-based Modelling (Use Case diagram).

Use-case diagram.

Use case diagram is similar to a top level data flow diagram that depicts observable, user-initiated functionality  in terms of interactions between the system and its environment.

There are two elements in use case diagram which is actor and use case. The relationship of use cases are uses and extends. We already discussed in details about how to generate use case diagram in the class. Figure below is an example for complete use-case diagram.

Example for Use-Case Diagram with the explanations. :)

So, you need to study more about  how to make use case diagram. Practice more to understand the concept of Use-case diagram. Practice makes perfect. InsyaAllah. :D

Posted by: Aema Ismail ( SW 095790 )