Essential System Analysis and Design Activities for Successful Development

1. IAD 2263: System Analysis and Design Chapter 3: Investigating System Requirements

2. Content • Analysis activities in more detail • System requirements • Models and modeling • Stakeholders – The source of system requirements • Techniques for Information Gathering • Validating the requirement

3. The Analysis Phase in More Detail • Gather information • Define system requirements • Functional and nonfunctional • Prioritize requirements • Prototype for feasibility and discovery • Generate and evaluate alternatives • Review recommendations with management

4. The Activities of the Analysis Phase ‏

5. Activities of the Analysis Phase and Their Key Questions‏

6. System Requirements • System requirements – specifications that define the new system • Functional requirements • Activities system must perform (use cases)‏ • Based on procedures and business functions • Documented in analysis models

7. System Requirements (cont)‏ • Nonfunctional requirements • Technical requirement – hardware and software • Performance requirement – workload measures • Usability requirement – user interface, workflow • Reliability requirement – outages, error detection • Security requirement – access & protection

8. Models and Modeling • Analyst describes information system requirements using a collection of models • Complex systems require more than one type of model • Models represent some aspect of the system being built • Process of creating models helps analyst clarify and refine design • Models assist communication with system users

9. Stakeholders—The Source of System Requirements • People with interest in successful system implementation • Three primary groups of stakeholders • Users (use system)‏ • Clients (pay for and own system)‏ • Technical staff (ensure system operation)‏ • Every type of stakeholder is identified by analyst

10. Stakeholders Interested in New System Development

11. Techniques for Information Gathering • Analysis phase done to understand business functions and develop system requirements • Original structured approach • Create model of existing system • Derive requirements from existing system model • Current approach • Identify logical requirements for new system • Balance the review of current business functions with new system requirements

12. Relationship Between Information Gathering and Model Building‏

13. Validating the Requirements • Make sure gathered information is correct • Structured walkthrough • Effective means of implementing quality control early in project • Verify and validate system requirements • Review of findings from investigation and of models based on findings • Project manager responsible for system quality • Systems analyst, project manager are partners

14. Structured Walkthrough Form

15. Activity Diagrams • Workflow – sequence of steps to process a business transaction • Activity Diagram – workflow diagram to describe sequence of steps • Synchronization bar – symbol to control splitting or merging of a path on an activity diagram • Swimlane – bounded area that contains activities of a single agent

16. Activity Diagram Symbols

17. Activity Diagramthat Models a Workflow

18. Activity Diagram with Concurrent Paths

19. Build Prototypes • Prototype - Preliminary working model of a larger, more complex system component • Discovery, design, evolving prototypes • Prototype should be • Operative • Working model to provide “look and feel” • Focused to accomplish single objective • Quick • Built and modified rapidly with CASE tools

20. Distribute and Collect Questionnaires • Limited and specific information from a large number of stakeholders • Preliminary insight into business • Not well suited for gathering detailed information • Closed-ended questions direct person answering question • Open-ended questions encourage discussion and elaboration

21. Class Activity- Case Study on activity diagram • Develop an activity diagram based on the following narrative. • The purchasing department handles purchase requests from other departments in the company. People in the company who initiate the original purchase request are the "customers" of the purchasing department. A case worker within the purchasing department receives that request and monitors it until it is ordered and received. • Case workers process requests for the purchase of products under $1,500, write a purchase order, and then send it to the approved vendor. Purchase requests over $1,500 must first be sent out for bid from the vendor that supplies the product. When the bids return, the case worker selects one bid. Then, he or she writes a purchase order and sends it to the vendor.

22. Case Study Answer

23. You are never too old to set another goal or to dream a new dream.~C. S. Lewis~ Thanks