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Value-Based Software Quality Achievement Process Modeling. LiGuo Huang [email protected] Computer Science Department Andrew & Erna Viterbi School of Engineering University of Southern California February 16, 2006. Outline. Value-Based Software Quality Achievement (VBSQA) Process

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Value-Based Software Quality Achievement Process Modeling

LiGuo Huang

[email protected]

Computer Science Department

Andrew & Erna Viterbi School of Engineering

University of Southern California

February 16, 2006


  • Value-Based Software Quality Achievement (VBSQA) Process
  • Experience of Applying VBSQA Process
  • VBSQA-OPN Model
  • VBSQA Process Generator
  • Conclusions and Future Work


real world software quality achievement
Real-World Software Quality Achievement
  • Heterogeneous group of stakeholders with different (sometimes even conflicting) quality perspectives
  • Developing a process for software quality achievement needs to address the following problems
    • Quality (Q-) attributes are not neatly orthogonal or independent
    • Same stakeholder’s strengths of dependencies on Q-attributes even vary in project development life cycle
    • A flexible process is expected in real-world application


research question


combinations of

quality (Q-)





Monitor and Control

Research Question

Value Propositions

Value-Based Metrics


Value-Based Models


characteristics of vbsqa process
Characteristics of VBSQA Process
  • Identify value conflicts on Q-attributes through risk analysis, architecture/technology evaluation and milestone reviews
  • Resolve conflicts by performing tradeoff analyses
  • A great deal of concurrency and backtracking
  • Achieve stakeholder WinWin-balanced software quality requirements


application of vbsqa process
Application of VBSQA Process
  • USC/NASA Inspector SCRover project
  • Real-world Enterprise Resource Planning (ERP) software development in China (DIMS upgrade project in Neusoft)
    • A variety of stakeholders with different value propositions
    • Product lines are maintained as a basis for future upgrades
    • Three process patterns: deadline-driven, product-driven, market-trend driven
    • Different software quality assessment criteria and different software development activities are adopted in different process patterns.


experience of applying vbsqa process
Experience of Applying VBSQA Process
  • Two week tutorials on VBSQA Process and WinWin Spiral Model
    • Developed a process instance composed of 22 ERP software development activities
      • 6 misplaced activities due to misinterpretation
      • 4 missing activities
  • Feedback from project managers of ERP solution providers
    • Shorten the new process learning curve
    • Maintain the flexibility of the process
    • Identify the flaws in a process instance
    • Tradeoffs among conflicting software Q-attributes
    • Determine stakeholders’ perspectives and interaction points


model vbsqa process using object petri nets opn
Model VBSQA Process Using Object Petri Nets (OPN)
  • Inherit the merits of Petri Nets (PN)
    • Formal semantics despite the graphical nature
    • State-based instead of event-based
    • Abundance of analysis techniques
    • Model concurrent process activities
  • Support separation of concerns among various stakeholders’ perspectives
    • Object-oriented approach
    • Model VBSQA Process Framework as the System Net (SN)
    • Model each stakeholder’s process instance in a separate Object Net (ON)
      • Process activities in ONs are inherited from process steps/milestones in SN
    • Interaction/negotiation among stakeholders and the SN/ON synchronization can be defined later


formal definitions of vbsqa opn
Formal Definitions of VBSQA-OPN
  • An OPN is a 3-tuple
    • System Net: is a Petri Net with its tokens referring to Object Nets
    • Object Nets: (n>1)
    • SN and ONs synchronize via “channels” ρ
    • System Net: , VBSQA Process Framework or its tailoring
    • Object Nets: (n>1) represents a set of process instances of stakeholders,
    • Synchronization relation between SN and ONs:
    • , a mapping between VBSQA process framework steps/milestones and ERP software development activities.
    • Guard functions: activation condition(s) of transitions
    • Constraint 1: Inheritance of chronological order
    • Constraint 2: Critical Path Dependency


vbsqa process checker identifying the flaws in a vbsqa process instance
VBSQA Process Checker– Identifying the Flaws in a VBSQA Process Instance
  • Maintain the flexibility of the process
    • Allow project managers to inherit a NULL activity from each step in the SN (VBSQA process framework)
      • Introduce the flaws of missing activities to violate critical path activity dependencies
  • VBSQA Process Checker
    • Formal properties defined in the VBSQA-OPN System Net (SN) and implemented in the VBSQA Process Checker
  • Examples of the activity dependency constraints in the SN
    • SCS define acceptable & desired values for Q-attributes must be completed before Risk analysis & architecture/technology evaluation
    • Risk analysis & architecture/technology evaluation must be completed before System top-level design
    • System top-level design must be completed before LCO Review


modeling costs and benefits
Modeling Costs and Benefits
  • Costs
    • Mutual learning: 24 hrs (3 days)
    • Developing plan: 2 hrs (DIMS upgrade project)
    • V&V of plan: 4 hrs (DIMS upgrade project)
    • Improving plan: 3 hrs (DIMS upgrade project)
  • Benefits
    • Time, effort saved: total 66 hrs in DIMS upgrade project
      • Mutual learning: 56 hrs (= 80 hrs - 24 hrs)
      • Developing plan: 6 hrs (= 8 hrs - 2 hrs)
      • V&V of plan: 4 hrs (= 8 hrs - 4 hrs)
    • User satisfaction:
      • More confident in generated project plans
      • Simulation results are very helpful in optimizing project plans
      • Easy to learn


conclusions and lessons learned
Conclusions and Lessons Learned
  • Value-Based Software Quality Achievement (VBSQA) process
    • helps in achieving stakeholder WinWin-balanced project quality outcomes
  • VBSQA-OPN model: synchronized and stabilized the activities, value propositions, and commitments of multiple success-critical stakeholders.
  • Process visualization and simulation tools significantly increased management visibility and controllability
  • OPN provides a feasible solution to the value-based process modeling
  • Future work: more simulations on VBSQA Process Generator


Backup Slides


vbsqa process creator map erp software development activities into vbsqa process framework
VBSQA Process Creator– Map ERP Software Development Activities into VBSQA Process Framework
  • Objectives:
  • To shorten the VBSQA process learning curve
  • To reduce the flaws such as the misplacement of ERP development activities due to the misinterpretation of the process steps when creating a process instance
  • To adapt to the changes in ERP software development activities and/or workflows


vbsqa process simulator
VBSQA Process Simulator
  • ROI of Synchronous Stakeholder Interaction Activities
    • ROI = (Value – Cost)/Cost
    • Value:
  • V: the total value of the project;
  • Eij (0-1): the effectiveness of a specific process activity on mitigating
  • the risk of Q- attribute i if it is performed in phase j;
  • Ri (0-1): the risk of Q-attribute i to the total value of the project.
    • Cost = Activity Cost + Rework Cost
  • Various combinations of synchronous stakeholder interaction activities and developer internal activities