Software Process Models-ii

1. Software Process Models-ii Presented By; Mehwish Shafiq

2. Pros and Cons of Prototype • Both customer and developer likes the prototype approach • Requirement gathering is quick and easy • Inherits iteration • No proper analysis phase • Requirement focus is on customer visualization • Developer trade-off requirements for technical limitations in start

3. Our Goal! • Primary Goal: High Quality • High Quality = Project Timeliness (coz its Less Rework)

4. Software Risks • Project Risk: • Threaten project plan, Budget, staffing. • Technical Risks: • Threaten quality, time schedule • Business Risk: • Developing product that no one really wants • Developing a product that no longer fits business strategy • Loosing budget and/or personnel commitment

5. RAD-Iterative Model • Extremely short development cycle using Component base construction. • When requirements are well defined and project scope is constrained.

6. RAD-Phases • Business modeling (What info drivers the business process? What info is generated? Who generates? Where the info go? Who processes it? • Data Modeling Set of data objects to support business • Process Modeling Processing requirements created to add, manage, delete and transform objects • Application Engineering Reuse or create reusable • Testing and turnover Many components already tested. Integration test is critical.

7. Spiral Model • Customer communication: Establish effective communication between customer and developer • Planning: Define resources, timelines and other project information • Risk Analysis: Asses both technical and management risks • Engineering : Build representation of the applications, via prototyping, increments etc • Construction and release: Construct, test , install and provide user support

8. Agile Methodologies • Agile process • Focus on Small and medium sized projects (Small Teams) • Progressing, not spending too much time on design and specification that might be useless • Agility • Adaptable instead of predictable • Light weight methodologies • Minimizing risk by short term focus (1-8 Weeks)

9. Agile Manifesto • Individuals and interaction over processes and tools • Close daily cooperation • Self organizing teams • Trust in motivated individuals • Working software over comprehensive documentation • Working software is the principal measure of progress • Simplicity • Customer collaborations • Customers involved at each and every step • Responding to change over following a plan

10. Agile processes • In this module we will study • eXtreme Programming (XP) • Dynamic Systems Development Methodology (DSDM)

11. XP

12. XP Phases • Exploration Phase: • User stories FR and NFR gathered and prioritized (story cards are developed) • Planning phase: • time required to implement each story card is estimated • Iteration to release phase • Prioritized story cards are implemented. Iteration is 1-4weeks long. Design and coding is done

13. XP-Phases • Productionizing phase • Testing is done here. Story cards are validated. • Maintenance phase • Customer are supported by probably new team. • Improvement suggestions are considered and fulfilled. • Death phase • End of software development

14. XP-Practices • The planning game • Iteration planning: predicting what will be accomplished by the due date • Release planning determining what to do next. • Planning involves breaking up a project into short iterations of 1-3 weeks and undertaking the project one iteration at a time. At the end of iteration, system is presented before customers for feedback. • Small Releases • Release working-s/w after every 2-3 weeks for customer evaluation • This makes software visible and keeps everything open. • Early feedback from customers enables developers to know about the functionality of system

15. XP Practices • Pair Programming • Pair of programmers work together and develop system artifacts. • Pairs are exchanged, everyone knows each part of system. • Pairing provides better code, better acceptance tests, and effective knowledge sharing between developers. • Onsite Customer • In XP customers work with the developers during the course of product development to help understand each others’ problems. • In this way the turnaround time for queries is reduced and also it prevents developers from making incorrect assumptions about requirements.

16. DSDM

17. DSDM Phases • Feasibility study • Conducted to evaluate technical feasibility of project for the use of DSDM. • Result = feasibility report. • Business study • FR and NFR specified & prioritized. • Customer is involved in business study. • Result= Business area definition containing ER Diagrams & use cases. • Functional model iteration • Iterative process • Prototype is developed, contains only FR (multiple iterations). • Analysis model is defined to analyze the prototype. • Prototype review document contains user comments. • List of NFR for this prototype is generated. • Risk analysis document for next prototype is produced.

18. DSDM Phases • Design and Build iteration • Iterative process • Prototype is completed by adding NFR Tested and reviewed by customer. • Implementation • Iterative process • Developed system is transferred into real application field. • Result= user manual & project review document (project’s outcomes).

19. Why Projects Fail? • Unrealistic deadline is established • Changing customer requirements • An honest underestimate of efforts • Predictable and/or unpredictable risks • Technical difficulties • Miscommunication among project staff • Failure in project management

20. Thank You!