Adaptation of Evolving
Requirements : A Managed
approach for Non-functional
requirements
Tanya Kudchadker
Nivedita Angadi
Guides:
Dr. A. Serebrenik (TU/e)
Martijn Klabbers, ir(LaQuSo)
Requirements Management - Steps
• Requirement Elicitation
• Requirement Analysis
• Requirement Specification
• Requirement Validation
Introduction
/ SET Seminar
Evolution
Current
Approach
NFR
12/02/2009 PAGE 2
Research
Goal
Current
Work
Further
Tasks
Summary
References
Requirements Evolution
• Royce 1970, “Waterfall model”.
− What is requirements
evolution?
In which stage does
requirements evolution
begin?
Introduction
/ SET Seminar
Evolution
Current
Approach
12/02/2009 PAGE 3
NFR
Research
Goal
Current
Work
Further
Tasks
Summary
References
Requirements Evolution Cycle
Introduction
/ SET Seminar
Evolution
Current
Approach
12/02/2009 PAGE 4
NFR
Research
Goal
Current
Work
Further
Tasks
Summary
References
Driving factors for Requirements Evolution
• Users need change
• Changes in the environment
• Adoption of new technologies
• Co-operative computing
Introduction
/ SET Seminar
Evolution
Current
Approach
12/02/2009 PAGE 5
NFR
Research
Goal
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Work
Further
Tasks
Summary
References
Is the requirement acceptable?
/ SET Seminar
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Change Management
• Process to implement changes in the system.
• Changes need to be formally introduced and
approved.
• Request For Change(RFC) form
Introduction
/ SET Seminar
Evolution
Current Approach
12/02/2009 PAGE 7
NFR
Research
Goal
Current
Work
Further
Tasks
Summary
References
Change management
/ SET Seminar
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Non functional requirements
• Why are non-functional requirements(NFR)
important?
• NFRs are often neglected or forgotten.
• Ineffectively dealing with NFRs can lead to a series
of failures in software development.
Introduction
/ SET Seminar
Evolution
Current
Approach
NFR
12/02/2009 PAGE 9
Research
Goal
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Work
Further
Tasks
Summary
References
The need of the hour
• A methodical process to assess the consequences
of the requirement change.
• Emphasis on Non-functional requirements.
• Practical guidelines to accept or reject the proposed
change.
Introduction
/ SET Seminar
Evolution
Current Approach
NFR
12/02/2009 PAGE 10
Research Goal
Current
Work
Further
Tasks
Summary
References
Types of changes
Introduction
/ SET Seminar
Evolution
Current Approach
NFR
12/02/2009 PAGE 11
Research
Goal
Current Work
Further
Tasks
Summary
References
Process Model
• Sequence of steps for handling new or changing
requirements during life time of a system.
Requirement Change
Identify change
Introduction
/ SET Seminar
Evolution
Current Approach
NFR
12/02/2009 PAGE 12
Research
Goal
Current Work
Further
Tasks
Summary
References
Environment Change
• Identify change in the environment
• Analyze the change for its effects.
Introduction
/ SET Seminar
Evolution
Current Approach
NFR
12/02/2009 PAGE 13
Research
Goal
Current Work
Further
Tasks
Summary
References
Requirement Change
• Identify the possible requirement change to the
existing system.
Introduction
/ SET Seminar
Evolution
Current Approach
NFR
12/02/2009 PAGE 14
Research
Goal
Current Work
Further
Tasks
Summary
References
Impact Analysis
• Impact of requirement changes on
• Non-functional requirements associated with the
proposed change.
• Viewpoints of each stakeholder.
Introduction
/ SET Seminar
Evolution
Current Approach
NFR
12/02/2009 PAGE 15
Research
Goal
Current Work
Further
Tasks
Summary
References
Design Change
• Identify implications to the existing design of the
system.
Introduction
/ SET Seminar
Evolution
Current Approach
NFR
12/02/2009 PAGE 16
Research
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Further
Tasks
Summary
References
Further tasks
• Refinement of the process model.
• Application of the model on a case study and identify
the various non-functional requirements which led to
its failure.
• E.g. London Ambulance Service Computerised Despatch
System(LASCDS)
Introduction
/ SET Seminar
Evolution
Current Approach
NFR
12/02/2009 PAGE 17
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Further Tasks
Summary
References
Summary
• Requirements evolution is a continuous process.
• Various factors drive the initiation of requirements evolution.
• Acceptance of these changes is a critical task.
• Non functional requirements play a big role in system ‘wellbeing’.
• A practical method/guidelines is a necessary for decision over
acceptance of such changes.
Introduction
/ SET Seminar
Evolution
Current Approach
NFR
12/02/2009 PAGE 18
Research
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Work
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Tasks
Summary
References
References
• Nazim H. Madhavji Juan Fernandez-Ramil, and Dewayne Perry:
Software Evolution and Feedback: Theory and Practice. John
Wiley & Sons, 2006.
• Lam, W., Loomes, M.: Requirements Evolution in the Midst of
Environmental Change: A Managed Approach, IEEE Computer
Society, 1998
• Cysneiros L.M., Leite J.C.S.P.: Nonfunctional Requirements:
From Elicitation to Conceptual Models. IEEE Transaction in
Software Engineering, 30(5):328–350, May 2004
Introduction
/ SET Seminar
Evolution
Current
Approach
NFR
12/02/2009 PAGE 19
Research
Goal
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Further
Tasks
Summary
References
Questions?
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