ANALYSIS AND DESIGN - I

 

Objectives

• To explore function-oriented design by developing a data flow diagram for the defined problem
   

Description

The design of a system is essentially a blueprint or a plan for a solution for the system. The design process for software systems often has two levels. At the first level the focus is on deciding which modules are needed for the system, the specifications of these modules, and how the modules should be interconnected. This is what may be called the module design or the high-level design. In the second level, the internal design of the modules, or how the specifications of the module can be satisfied, is decided. This design level is often called detailed design or logic design. Detailed design essentially expands the system design to contain a more detailed description of the processing logic and data structures so that the design is sufficiently complete for coding.

Many design techniques have been proposed over the years to provide some discipline in handling the complexity of designing large systems. In this exercise, you will be introduced to function-oriented system design. The methodology employs the structure chart notation for creating the design.

Tools

StarUML: StarUML is an open source project to develop fast, flexible, extensible, featureful, and freely-available UML/MDA platform running on Win32 platform. The goal is a compelling replacement of commercial UML tools such as RationalRose.

Procedure

Structure charts: The structure chart of a program is a graphic representation of its structure. In a structure chart a module is represented by a box with the module name written in the box. An arrow from module A to module B represents that module A invokes module B. B is called the subordinate of A, and A is called the superordinate of B.

Structured Design Methodology:

• Identify the Most Abstract Input and Output Data Elements

• Do First-Level Factoring

• Factor the Input, Output, and Transform Branches

• Draw the DFD

Problem

Identify the modules of your system and give a graphical representation of its structure with the help of a structure chart. Also draw a DFD focusing on input, output data elements and transform branches.

 

Deliverables

• Structure chart

• Data Flow Diagram

References

• Pankaj Jalote: A Concise Introduction to Software Engineering , Springer, 2008, pg. 131-140

• Roger S. Pressman: Software Engineering A Practitioner's Approach, 7th Edition, McGraw Hill, 2010, pg. 226-231