Requirements Engineering

1. Requirements Engineering University of Palestine Faculty of Engineering and Urban planning Software Engineering department Mohammad Amin KuhailM.Sc. (York, UK) Nonfunctional Requirements

2. NFR Definition IEEE “non functional requirement – in software system engineering, a software requirement that describes not what the software will do, but how the software will do it, for example, software performance requirements, software external interface requirements, design constraints, and software quality attributes. Nonfunctional requirements are difficult to test; therefore, they are usually evaluated subjectively.”

3. NFR Definition Definition 􀁺 Non-functional requirements define the overall qualities or attributes of the resulting system. 􀁺 Non-functional requirements place restrictions on the product being developed, the development process, and specify external constraints that the product must meet.

4. NFR Definition Observation “non functional requirement – generally informally stated, often contradictory, difficult to enforce during development and evaluate for the customer prior to delivery”

5. NFR What are they? What are they? • -ilities: understandability, usability, modifiability, inter-operability, • reliability, portability, maintainability, scalability, (re-)configurability, • customizability, adaptability, variability, volatility, traceability, … • -ities: security, simplicity, clarity, ubiquity, integrity, modularity, • nomadicity, … • -ness: user-friendliness, robustness, timeliness, responsiveness, • correctness, completeness, conciseness, cohesiveness, … • …and many other things: performance, efficiency, • accuracy, precision, cost, development time, low coupling, …

6. NFR Classification NFR Classifications

7. NFR Classification NFR Classifications

8. NFR Classification NFR Classifications

9. NFR Classification NFR Classifications

10. NFR Classification NFR Classifications

11. FR Vs NFR NFR Vs. Functional Requirements

12. NFR Descriptions and ways to measure NFR Vs. Functional Requirements

13. NFR Descriptions and ways to measure NFR Vs. Functional Requirements

14. NFR Descriptions and ways to measure NFR Vs. Functional Requirements

15. NFR Descriptions and ways to measure Example

16. NFR Descriptions and ways to measure NFR Vs. Functional Requirements

17. NFR Descriptions and ways to measure

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21. NFR Descriptions and ways to measure

22. NFR Descriptions and ways to measure

23. NFR Descriptions and ways to measure

24. NFR Descriptions and ways to measure NFR Vs. Functional Requirements

25. NFR Descriptions and ways to measure NFR Vs. Functional Requirements

26. NFR Descriptions and ways to measure NFR Vs. Functional Requirements

27. NFR Descriptions and ways to measure NFR Vs. Functional Requirements

28. NFR Descriptions and ways to measure

29. NFR properties NFR Vs. Functional Requirements

30. NFR properties NFR Vs. Functional Requirements

31. NFR Derivation

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34. NFR Derivation

35. NFR Vs. Functional Requirements

36. NFR Derivation

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45. NFR Modeling

46. NFR Modeling