Example: Writing a research paper.
Draw Context Diagram
External Entities: Professor, Library
Context diagram establishes the boundary
between the system and the external environment, i.e., shows scope
Level 0 begins system description.
Step 2: decompose process - list activities involved, and then group those activities into three to ten major processes.
Use major processes and external entities and data flows from
context diagram to develop Level 0 DFD.
Level 0 DFD: Write Research Paper
Analyze each process in Level 0 to derive Level 1 diagrams.
(In this example, the Level 1 diagram
will consist of four diagrams: Level 1 Diagram 1, Level 1 Diagram
2, Level 1 Diagram 3, and Level 1 Diagram 4.)
Technique: Identify functions and what
is needed to conduct functions.
example: What happens in Determine Paper Topic?
Remember that every flow in or out of
Determine Paper Topic process on Level 0 must be shown in Level
1 Diagram 1: Determine Paper Topic.
Show boundary with dotted line.
Level 1 Diagram 1: Determine Paper Topic
example: What happens in Perform Research?
example: What happens in Prepare Draft?
example: What happens in Finalize Paper?