What is a Model and Modelling ?

In any software life-cycle, the suggested distribution of effort is : 

• Requirements Capture : 15%
• Analysis & Design :   25%
• Implementation : 40%
• Testing : 20%

Analysis - What is to be done ? ( What are the building blocks ? )

Design - How is it to be done ? ( How they should be put together ? )

Modeling

In object oriented approach,  Analysis phase  is accomplished by discovering classes and objects in the problem definition.

Design phase  is realized creating a software architecture , capturing  both the structure & behavior of the system.

Modeling is simplification of reality.

Modeling helps us achieve these aims : 

• Models help us to understand the working of a system before actually building it.
• Models permit us to specify the structure or behavior of a system.
• Models give us a template that guides us in constructing a system.
• Models document the decisions we have made.

Elements of a model

Notation: It is used as iconic language for expressing each model of a system.
                 These should be standardized notations.

Process: The activities leading to the orderly construction of the system models.

Tools:  It is the automated support to assist the process of analysis and design.