1. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE1 LiGuo Huang liguohua@usc.edu Computer Science Department Andrew & Erna Viterbi School of Engineering University of Southern California February 16, 2006 Value-Based Software Quality Achievement Process Modeling

2. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE2 Outline Value-Based Software Quality Achievement (VBSQA) Process Experience of Applying VBSQA Process VBSQA-OPN Model VBSQA Process Generator Conclusions and Future Work

3. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE3 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

4. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE4 Research Question Stakeholders Define Negotiate Develop Monitor and Control Mission-specific combinations of quality (Q-) attributes Value-Based Metrics Value-Based Models Process Value Propositions

5. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE5 Value-Based Software Quality Achievement (VBSQA) Process

6. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE6 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

7. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE7 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.

8. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE8 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

9. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE9 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

10. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE10 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 ON s synchronize via “channels” ρ VBSQA-OPN = –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 ON s :, 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

11. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE11 VBSQA Process Generator – Based on VBSQA-OPN Model

12. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE12 VBSQA Process Creator – Creating an ERP VBSQA Process Instance

13. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE13 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

14. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE14 VBSQA Process Simulator – ROI of Synchronous Stakeholder Interaction Activities

15. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE15 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

16. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE16 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

17. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE17 Backup Slides

18. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE18 VBSQA Process Creator – Map ERP Software Development Activities into VBSQA Process Framework VBSQA Process Framework Steps/Milestones (System Net) ERP Software Development Activities (Object Nets) Project cost/benefit analysisEstimate system upgrade cost & develop DMR results chain (Developer) Verify system upgrade cost (System Acquirer) SCS define acceptable & desired values for Q-attributes Requirement elicitation meeting Groupware WinWin negotiation LCA ReviewSelected architecture internal review (Developer) Selected architecture external review CCDInternal core capability demo (Developer) Onsite core capability demo 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

19. University of Southern California Center for Software Engineering C S E USC 02/16/05©USC-CSE19 VBSQA Process Simulator ROI of Synchronous Stakeholder Interaction Activities –ROI = (Value – Cost)/Cost –Value: V: the total value of the project; E ij (0-1): the effectiveness of a specific process activity on mitigating the risk of Q- attribute i if it is performed in phase j; R i (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