Quality Attribute Workshop

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Quality Attribute Workshop
Presented By Biswajit Jena
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Outline

• Introduction
• Motivation
• QAW Methods
• QAW Benefits
• Conclusion

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Introduction

• A system has 3 requirements
• Functional
• Non-functional
• Constraints
• Quality Attribute
• Any property of the system which has nothing to
  do with functionality.

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Introduction (contd.)
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Importance of Quality Attributes

• Importance of Quality attributes
• They define the system properties.
• System working conditions.
• Driver for Architecture design

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Quality Attribute Workshop

• Quality Attribute Workshop
• It helps the system architects to get maximum
  possible information about the quality.
• It helps in defining the structure of the system.
• The QAW is one way to discover, document, and
  prioritize a systems quality attributes early in
  its life cycle.

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QAW Procedure
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QAW Process
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Trade-off Analysis

• Why cant a system have all the quality?
• For example, if a system has to be both fast and
  secure than there has to be tradeoff between
  these qualities of the system.
• Some quality attributes are competing in nature.
• Things may mean different to different people.
• You apply tactics to achieve the quality goals.
• Say for Security of a system
• Encryption
• Firewall

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Trade-off Analysis (contd.)
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Traditional System Development
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Motivation

• What is motivation of holding QAWs?
• To go beyond functionally correct answers
• A system should meet functional and quality
  requirements.

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Quality Attribute roadmap
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Motivation ( contd.)

• What problems do we face when we dont consider
  quality attributes?
• Performance goals are not met.
• System not available when needed.
• If change made in one part, it affects a large
  portion of the system.

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Motivation (contd.)

• Quality attributes should be made more concrete.
• Modifiability
• Challenges in addressing quality attributes in
  architectural design.
• What is the precise meaning of quality attributes
• How can you discover, characterize and prioritize
  the key quality attributes before the system is
  built?
• How can you engage the stakeholders in taking
  decision?
• How can all the information be used?

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QAW Method

• What is QAW?
• Is a facilitated early invention method used to
  generate, prioritize and refine attribute
  scenarios before software architecture is
  completed.
• QAW is dependent on participations of
  stakeholders.
• Users, Installers, DBMS managers
• Architects, developers
• Security auditors

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QAW Method (contd.)

• Where do qualities attributes come into picture
  in a software system ?
• While designing the architecture of the system.
• Identify Stakeholders
• Architects
• Developers
• Users
• Sponsors

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QAW Method Steps (contd.)

• QAW presentation and Introduction
• Business/Mission Presentation
• Architecture Plan Presentation
• Identification of Architectural Drivers
• Scenario Brain Storming

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QAW Method Steps (contd.)

• Scenario Consolidation
• Scenario Prioritization
• Scenario Refinement

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QAW Benefits

• Results of QAW include
• A list of Architectural Drivers
• The raw scenarios
• The prioritized list of raw scenarios
• The refined scenarios

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QAW Benefits (contd.)

• The information can be used to
• Update the architectural vision.
• Refine System and software requirements.
• Guide the development of prototypes.
• Exercise Simulations.
• Understand and clarify the systems architectural
  drivers.
• Describe the operation of the system.
• Influence the order the architecture is developed.

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Conclusions

• QA requirements must be recognized and considered
  early in the life cycle.
• QAW is a method for eliciting and explicitly
  documenting quality attribute requirements.
• Also provides mechanism for capturing other
  architecturally relevant materials.
• Refined scenarios can be graduated to sequence
  diagrams or collaboration diagrams.

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Questions

• What are quality attributes?
• Why quality attributes are important?
• Where do quality attributes feature in the life
  cycle stage?
• Meeting quality requirements Are they overheads
  or value additions?
• Why cant we have all the good things in a
  software?

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Questions
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References

• http//www.sei.cmu.edu/publications/documents/03.r
  eports/03tr016.html
• https//www.cmpevents.com/SDUM6/a.asp?optionGV3
  id423791