1. Data Flow Diagrams Introduction for organizers

2. The Problem How to model a system before building or changing it

3. Build an Abstraction Molecular Model

4. Life Cycle

5. What Life Cycle? What does it do? –All or Part? Build or Buy? –Early decision for all software systems are whether to build or buy WHO works on it? WHO will run it? HOW Long will it last?

6. The Software Development Cycle 1.Identify problems, opportunities and objectives. 2. Define Information Requirements 3. Analyze Detailed Needs 4. Specify or Design the Recommended System 5. Buy or Develop the Software 6. Install and Test 7. Train 8. Deploy 9. Maintain the system 10. Evaluate and Plan for New Versions Symbol of never-ending life

7. Different Points of View

8. Put the Parts Together Organization’s Requirements Technical Experts User Experts Technology

9. Who Does What? Technical Assistance Provider User Expert Joint Effort

10. Who Does What? 1.Identify problems, opportunities and objectives. 2. Define Information Requirements 3. Analyze Detailed Needs 4. Specify or Design the Recommended System 5. Buy or Develop the Software 6. Install and Test 7. Train 8. Deploy 9. Maintain the system 10. Evaluate and Plan for New Versions Technical Assistance Provider User Expert Joint

11. Data Flow Diagram Parts External Entity Process Data Flow Data Store

12. External Entity The External Entity symbol represents sources of data to the system or destinations of data from the system. Funder Politician Allies General Population Constituency Government Funder Politician Allies General Population Constituency Government

13. Process The Process symbol represents an activity that transforms or manipulates the data (combines, reorders, converts, etc.). Signup Member Plan campaign Communicate message Pay Bills Signup Member Plan campaign Communicate message Pay Bills

14. Data Flow The Data Flow symbol represents movement of data. All Data Flows are defined in a data dictionary

15. Data Store The Data Store symbol represents data that is not moving (delayed data at rest).

16. Procedure 1.Start at the top level with external entities to organization 2.Create a context diagram with system at center and external entities sending and receiving data flows;

17. Context Diagram

18. Carry Entities and Data Flows Forward

19. Level 1 CLO Example

20. Level 1 CLO Example

21. Exercise