1. CS251 – Software Engineering Lecture 21 Process and Life Cycle

2. حكمة اليوم 1. أفلم يسيروا في الأرض فتكون لهم قلوب يعقلون بها أو آذان يسمعون بها 2.فإنها لا تعمى الأبصار ولكن تعمى القلوب التي في الصدور

3. 1/26/20163 Assessment Midterm exam (5%) Project (15% = 5 + 5 + 5 + 1 + Bonus) Quizzes (10 + 1%) Lab (5 + 1%) A1 (5%)

4. 1/26/20164 Lecture Outline SW Lifecycle SW Process Models

5. 5 Where are we now? Requirement Analysis Design Implement Testing Process Models Software Configuration Management Software Process

6. 6 Where are we now? Requirement Analysis Design Implement Testing Process Models Software Configuration Management Software Process

7. 1/26/20167

8. 1. Software Life Cycle Conception Feasibility Study / Domain Analysis Requirements’ Gathering Overall Design Detailed Design Development (Coding, Programming) Testing (Unit, Integration, Acceptance) Deployment / Training Maintenance and Evolution

9. Process of Building a House Different Process Same life cycle

10. Software Life Cycle Conception Feasibility Study / Domain Analysis Requirements’ Gathering Overall Design Detailed Design Development (Coding, Programming) Testing (Unit, Integration, Acceptance) Deployment / Training Maintenance and Evolution Specification Development Validation Evolution

11. Important Terms Software life-cycle –Phases –Development cycle and evolution cycle Software process –Discipline, activities, roles, and artifacts Iterations –Milestones

12. Software Life Cycle (As in RUP) Conception Feasibility Study / Domain Analysis Requirements’ Gathering Overall Design Detailed Design Development (Coding, Programming) Testing (Unit, Integration, Acceptance) Deployment / Training Maintenance and Evolution Inception Elaboration Construction Transition

13. Phases of the Development Cycle T I M E Transition Construction Elaboration Inception Inception - Define the scope of project Elaboration - Plan project, specify features, baseline system Construction - Build the product Transition - Transition the product into end user community

14. 1/26/201614 Software Process The set of activities and associated results that produce a software product. Four fundamental process activities: –Software Specification –Software Development –Software Validation –Software Evolution Can be organized in different ways, described at varying level of details → different software development process models

15. 2. SE Process A software process model describes the activities performed to produce a software, the order of these activities, the roles responsible of them and the deliverables produced from each activity. The distinction between SDLC and SP is a not clear cut.

16. 1. Waterfall Model Requirements – defines needed information, function, behavior, performance and interfaces. Design – data structures, software architecture, interface representations, algorithmic details. Implementation – source code, database, user documentation, testing.

17. Waterfall Strengths Easy to understand, easy to use Provides structure to inexperienced staff Milestones are well understood Sets requirements stability Good for management control (plan, staff, track) Works well when quality is more important than cost or schedule

18. Waterfall Deficiencies All requirements must be known upfront Deliverables created for each phase are considered frozen – inhibits flexibility Can give a false impression of progress Does not reflect problem-solving nature of software development – iterations of phases Integration is one big bang at the end Little opportunity for customer to preview the system (until it may be too late)

19. When to use the Waterfall Model Requirements are very well known Product definition is stable Technology is understood New version of an existing product Porting an existing product to a new platform.

20. 2. Incremental SDLC Model Construct a partial implementation of a total system Then slowly add increased functionality The incremental model prioritizes requirements of the system and then implements them in groups. Each subsequent release of the system adds function to the previous release, until all designed functionality has been implemented.

21. Incremental Model Strengths Develop high-risk or major functions first Each release delivers an operational product Customer can respond to each build Uses “divide and conquer” breakdown of tasks Lowers initial delivery cost Initial product delivery is faster Customers get important functionality early Risk of changing requirements is reduced

22. 1/26/2016 CPSC-4360-01, CPSC-5360-01, Lecture 222 Incremental Model Each increment is a mini-waterfall.

23. Incremental Model Weaknesses Requires good planning and design Requires early definition of a complete and fully functional system to allow for the definition of increments Well-defined module interfaces are required (some will be developed long before others) Total cost of the complete system is not lower

24. When to use the Incremental Model Risk, funding, schedule, program complexity, or need for early realization of benefits. Most of the requirements are known up-front but are expected to evolve over time A need to get basic functionality to the market early On projects which have lengthy development schedules On a project with new technology

25. 3. Spiral SDLC Model Adds risk analysis, and prototyping to the waterfall model Each cycle involves the same sequence of steps as the waterfall process model

26. Spiral Quadrant Determine objectives, alternatives and constraints Objectives: functionality, performance, hardware/software interface, critical success factors, etc. Alternatives: build, reuse, buy, sub-contract, etc. Constraints: cost, schedule, interface, etc.

27. Spiral Quadrant Evaluate alternatives, identify and resolve risks Study alternatives relative to objectives and constraints Identify risks (lack of experience, new technology, tight schedules, poor process, etc. Resolve risks (evaluate if money could be lost by continuing system development

28. Spiral Quadrant Develop next-level product Typical activites: –Create a design –Review design –Develop code –Inspect code –Test product

29. Spiral Quadrant Plan next phase Typical activities –Develop project plan –Develop configuration management plan –Develop a test plan –Develop an installation plan

30. Spiral Model Strengths Provides early indication of insurmountable risks, without much cost Users see the system early because of rapid prototyping tools Critical high-risk functions are developed first The design does not have to be perfect Users can be closely tied to all lifecycle steps Early and frequent feedback from users Cumulative costs assessed frequently

31. Spiral Model Weaknesses Time spent for evaluating risks too large for small or low- risk projects Time spent planning, resetting objectives, doing risk analysis and prototyping may be excessive The model is complex Risk assessment expertise is required Spiral may continue indefinitely Developers must be reassigned during non-development phase activities May be hard to define objective, verifiable milestones that indicate readiness to proceed through the next iteration

32. When to use Spiral Model When creation of a prototype is appropriate When costs and risk evaluation is important For medium to high-risk projects Long-term project commitment unwise because of potential changes to economic priorities Users are unsure of their needs Requirements are complex New product line Significant changes are expected (research and exploration)

33. 4. Agile SDLC’s Speed up or bypass one or more life cycle phases Usually less formal and reduced scope Reduce documentation Embed quality activities in the development process Used for time-critical applications

34. Some Agile Methods Adaptive Software Development (ASD) Feature Driven Development (FDD) Crystal Clear Dynamic Software Development Method (DSDM) Rapid Application Development (RAD) Scrum Extreme Programming (XP)

36. Example SPs –Rational Unified Process –Scrum (Will be covered by Amr Samir) –Remember, a SW Development Process defines: activities (or Tasks), their order, roles and deliverables (or Work Products or artifacts).

37. 1. Rational Unified Process (RUP) RUP is an iterative software development process framework by the Rational Software Corporation, a division of IBM. It is not a single concrete prescriptive process, but rather an adaptable process framework, intended to be tailored. Organizations and software project teams will select the elements of the process that are appropriate for their needs.

38. UPEDU Is a version of RUP Project Management Environment Business Modeling Implementation Test Analysis & Design Phases Process Workflows Supporting Workflows Deployment Config & Change Mgmt Requirements ElaborationTransitionInceptionConstruction UPEDU http://www.upedu.org/

39. Weight of Disciplines in Iteration Varies Project Management Implementation Test Analysis & Design Life Cycle Phases Engineering Workflows Supporting Workflows Configuration & Change Mgmt Requirements ElaborationTransitionInceptionConstruction ITERATION A ITERATION E

40. Artifacts Evolve in the Develop. Cycle Management artifacts Requirements artifacts Design artifacts Implementation artifacts M R D I : : : : Inception RDIM Construction RDIM Transition RDIM Elaboration RDIM An iteration is a distinct sequence of activities with an established plan and evaluation criteria resulting in an modified artifacts

41. UPEDU Roles Analyst Designer Implementer Integrator Tester Change Control Manager Configuration Manager Project Manager Reviewer Any other Stakeholder

42. UPEDU Implementation Discipline: Activities

43. UPEDU Implementation Discipline: Artifacts

44. UPEDU Implementation Discipline: Activities

45. 2. Scrum Watch Amr Samir’s video under Acadox (11 min.) Very important and very nice explanation of Scrum. Will com in exam

47. Reviewing Course Objectives 1 Teaching students the disciplined approach to engineering software systems. Educating the students about the cost of software failures and the importance of software engineering. Training the students on applying engineering practices in software development. Introducing learners to the Software Engineering Body of Knowledge. 47

48. Course Objectives 2 Training them on the basics of software requirements engineering, modeling, and design, construction and configuration and process management. Training the students on system modeling using UML. Training students on teamwork. 48

49. Course Objectives 3 Coders - Can pretty much figure out it. It'll work, but it won't be pretty. Hackers - usually low level folks, skillful, with detailed understanding of some area deeply, often scarily deeply. Programmer - Write code and understand algorithms. Often work alone and well. Software Engineer - Are the best generalists, can use lots of different systems and languages and get them to talk to each other. Are true and broad professionals, work with people, and communicate well. 49

50. How to Study Lectures (slides and videos and code) Readings Quizzes + Lecture Practice Labs + Sections Previous exams and questions 50