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Chapter 4

Chapter 4. Beginning the Analysis: Investigating System Requirements. Review. What is a logical view vs. a physical view of an IS? What is and when do we use prototyping?. Objectives. Describe the activities of the systems analysis life cycle

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Chapter 4

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  1. Chapter 4 Beginning the Analysis: Investigating System Requirements

  2. Review • What is a logical view vs. a physical view of an IS? • What is and when do we use prototyping?

  3. Objectives • Describe the activities of the systems analysis life cycle • Describe the difference between functional and technical system requirements • Identify and understand the different types of users who will be involved in investigating system requirements • Describe the kind of information that is required to develop system requirements

  4. Objectives • Determine system requirements through review of documentation, interviews, observation, prototypes, questionnaires, vendor research, and joint application design sessions • Explain the contribution of business process reengineering to the definition of requirements • Discuss the need for validation of system requirements to ensure accuracy and completeness and the use of a structured walkthrough

  5. Analysis Phase in More DetailFigure 4-1

  6. Functional and Nonfunctional Requirements • System requirements – all capabilities and constraints • 1) Functional requirements • Activities the system must perform • Based on procedures and business functions • Documented in analysis models

  7. Functional and Nonfunctional Requirements con’t • Technical requirements • Describes operating environment or performance objectives • Documented in narrative descriptions of technical requirements • Performance requirements • Workload, throughput, output, response etc. • Usability • User interface, help, documentation, etc. • Reliability • Availability, accuracy, no-bugs • Security • Access to system functions

  8. Class Exercise • Nipissing has new grade reporting system. What are some of the functional and nonfunctional requirements of the new system. • Show datatel!

  9. Stakeholders • Users • User roles • Horizontal - information flow across departments • Vertical - information needs of clerical staff, middle management, and senior executives • Business/End users • Information users • Management users • Executive users • External users • Client stakeholders • Technical stakeholders Who are the stakeholders for the Nipissing grade reporting system?

  10. Techniques for Information Gathering • Objective of analysis phase is to understand business functions and develop requirements • Original approach involved modeling of existing system (bottom up) • E.g., Data/process class matrix • Current approach involves identifying logical requirements for new system (top down)

  11. Information Gathering and Model Building

  12. Themes for Information-Gathering Questions Help the user move beyond current system to determine what the new system should do! Users involved with the Datatel system are professors, registrar office, students. How do each respond to the questions?

  13. Fact Finding Methods • Review existing reports, forms, and procedure descriptions • Conduct interviews and discussion with users • Observe and document business processes • Build prototypes • Distribute and collect questionnaires • Conduct JAD sessions • Research vendor solutions

  14. Activity Diagram SymbolsFigure 4-11

  15. Simple Activity DiagramFigure 4-12

  16. Activity Diagram with Concurrent Paths

  17. Joint Application Development (JAD) Sessions • Used to expedite the investigation of systems requirements • Seeks to compress fact-finding, modeling, policy formation, and verification activities into a shorter time frame • Critical factor is to have all important stakeholders present • JAD Participants • JAD session leader • Users • Technical staff • Project team members

  18. Research Vendor Solutions • Many problems have been solved by other companies • Positive contributions of vendor solutions • Provide new ideas • May be state of the art • Cheaper and less risky • Danger • May purchase solution without understanding problem fully • Techniques in Vendor Research • Demo or trial system • References of existing clients • On-site visits • Printout of screens and reports

  19. Business Process Reengineering • Questions basic assumptions • Provides radical improvements • IT often used as integral part of BPR • System development project may include components of BPR

  20. Validating 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

  21. Business Process Reengineering • Questions basic assumptions for doing business and seeks to find a better way • Uses IT as an enabler • Systems analyst may discover opportunities for business process improvement

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