340 likes | 521 Views
USC CSSE Workshop Overview: Top 3 Software-Intensive Systems Risk Items. Barry Boehm, USC-CSSE February 14, 2007 http://csse.usc.edu/BoehmsTop10/ boehm@usc.edu. Outline: Top-3 SIS Risks Workshop. Working group guidelines Risk survey results and survey update(?) The top three risks
E N D
USC CSSE Workshop Overview:Top 3 Software-Intensive Systems Risk Items Barry Boehm, USC-CSSE February 14, 2007 http://csse.usc.edu/BoehmsTop10/boehm@usc.edu
Outline: Top-3 SIS Risks Workshop • Working group guidelines • Risk survey results and survey update(?) • The top three risks • Architecture complexity; system quality tradeoffs • Requirements volatility; rapid change • Acquisition and contracting process mismatches • Architecture complexity and system quality tradeoffs • Architecture complexity phenomenology • Nature of system quality • Quality tradeoff perspectives
Working Group Guidelines • Product: briefing, preferably with notes • Topics should include: • Most critical success factors in each area • Current best practices for addressing them • Areas for further research • Rated 0-10 on value and difficulty of research
Research Topics: Agile Methods • Relationship between plan driven and agility • For individuals • For organizations • Differences between agile and plan driven outcomes • Effect of Gurus • Mismatches between development approach and acquisition practices • How do you measure quality in an agile environment? • Data collection; agile experience base • Team of teams • Agile Development and Evolutionary Prototyping • Shared Code and/or module ownership • Architecture: when, how much, how to express • Lack of user consensus • Dynamic Homegrounds
SIS Risk Survey 2006: Statistics • Number of Surveys: 25 • Average Experience: ~28 years (6 years – 51 years) • Area Distribution: • Software: 20 • Systems: 17 • Hardware: 0 • Business Domain Distribution: • Aerospace: 18 • Software Infrastructure: 5 • Business: 4 • Telecom: 3 • Others: Secure Apps (1); Safety Critical Apps (1); C4ISR (1)
Risk Survey 2006: Nominees • Acquisition and contracting process mismatches • Architecture complexity; quality tradeoffs • Budget and schedule constraints • COTS and other independently evolving systems • Customer-developer-user team cohesion • Migration complexity • Personnel shortfalls • Process maturity • Requirements mismatch • Requirements volatility; rapid change • Technology maturity • User interface mismatch
Survey 2007: Early Statistics • Number or Surveys: 41 • Average Experience: ~27 years (6 years – 51 years) • Area Distribution: • Software: 33 • Systems: 34 • Hardware: 0 • Business Domain Distribution: • Aerospace: 32 • Software Infrastructure: 7 • Business: 6 • Telecom: 5 • Others: Secure Apps (1); Safety Critical Apps (1); C4ISR (1); Network and Protocols (1); Defense (1); Program and Risk Management (1)
Outline: Top-3 SIS Risks Workshop • Working group guidelines • Risk survey results and survey update(?) • The top three risks • Architecture complexity; system quality tradeoffs • Requirements volatility; rapid change • Acquisition and contracting process mismatches • Architecture complexity and system quality tradeoffs • Architecture complexity phenomenology • Nature of system quality • Quality tradeoff perspectives
Platform N • • • Platform 1 Infra C4ISR Breadth DOTMLPF 1.0 2.0 3.0 4.0 5.0 … Length 2008 2010 2012 2014 2016 Command and Control Situation Assessment Info Fusion Sensor Data Management Sensor Data Integration Sensors Sensor Components : Depth Requirements Volatility: Ripple Effects of Changes- Breadth, Depth, and Length Legend: DOTMLPF Doctrine, Organization, Training, Materiel, Leadership, Personnel, Facilities C4ISR Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance
Average Change Processing Time: 2 Systems of Systems • Average workdays to process changes
Acquisition/Contracting Mismatches: Fitness Landscapes • Role of Fitness Landscapes in Complex Adaptive Systems (CAS) • S. Kauffman, At Home in the Universe, Oxford University Press, 1995 • CSoS Acquisition Challenges • B. Boehm, “Some Future Trends and Implications for Systems and Software Engineering Processes”, Systems Engineering 9(1), 2006, pp. 1-19. • A Candidate Three-Agent Acquisition Fitness Landscape • D. Reifer and B. Boehm, “Providing Incentives for Spiral Development: An Award Fee Plan”, Defense Acquisition Review 13(1), 2006, pp. 63-79.
Role of Fitness Landscapes in CAS • Incentive structures for local behavior • Induce global behavior via adaptation to change
Outline: Top-3 SIS Risks Workshop • Working group guidelines • Risk survey results and survey update(?) • The top three risks • Architecture complexity; system quality tradeoffs • Requirements volatility; rapid change • Acquisition and contracting process mismatches • Architecture complexity and system quality tradeoffs • Architecture complexity phenomenology • Nature of system quality • Quality tradeoff perspectives
Percent of Project Schedule Devoted to Initial Architecture and Risk Resolution Added Schedule Devoted to Rework (COCOMO II RESL factor) Total % Added Schedule 10000 KSLOC Sweet Spot 100 KSLOC Sweet Spot Drivers: Rapid Change: leftward High Assurance: rightward 10 KSLOC Larger Systems Need More Architecting: COCOMO II Analysis
TRW Project B 1005 SPR’s 100 90 80 TRW Project A 373 SPR’s 70 % of Cost to Fix SPR’s 60 50 Major Rework Sources: Off-Nominal Architecture-Breakers A - Network Failover B - Extra-Long Messages 40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 100 % of Software Problem Reports (SPR’s) Architecture-Breakers are the Biggest Source of Rework
$100M Arch. A: Custom many cache processors $50M Arch. B: Modified Client-Server Original Spec After Prototyping 5 3 1 2 4 Response Time (sec) Best Architecture is a Discontinuous Function of Quality Level
The Nature of Quality: Participant Survey Which figure best symbolizes quality improvement?
There is No Universal Quality-Value Metric • Different stakeholders rely on different value attributes • Protection: safety, security, privacy • Robustness: reliability, availability, survivability • Quality of Service: performance, accuracy, ease of use • Adaptability: evolvability, interoperability • Affordability: cost, schedule, reusability • Value attributes continue to tier down • Performance: response time, resource consumption (CPU, memory, comm.) • Value attributes are scenario-dependent • 5 seconds normal response time; 2 seconds in crisis • Value attributes often conflict • Most often with performance and affordability
Quality of Service Adaptability Robustness Affordability Protection Attributes Stakeholders Info. Suppliers, Dependents ** * * Info. Brokers ** ** ** ** * Info. Consumers * ** * * Mission Controllers, Administrators ** * ** ** Developers, Acquirers * * ** ** Overview of Stakeholder/Value Dependencies • Strength of direct dependency on value attribute **- Critical ; *-Significant; blank-insignificant or indirect
Implications for Quality Engineering • There is no universal quality metric to optimize • Need to identify system’s success-critical stakeholders • And their quality priorities • Need to balance satisfaction of stakeholder dependencies • Stakeholder win-win negotiation • Quality attribute tradeoff analysis • Need value-of-quality models, methods, and tools
(RELY, MTBF (hours)) • For 100-KSLOC set of features • Can “pick all three” with 77-KSLOC set of features -- Cost/Schedule/RELY: “pick any two” points Tradeoffs Among Cost, Schedule, and Reliability: COCOMO IIWant 10K hour MTBF within $5.5M, 20 months
Agenda : Wednesday, Feb 14 • 8:15 – 10:00 am: Architecture Complexity and Quality Tradeoffs; Elliot Axelband (RAND), Chair • Overview, Issues and Approaches; Barry Boehm (USC) • From Dependable Architectures To Dependable Systems; Nenad Medvidovic (USC) • Architecture Tradeoff Analysis: Towards a Disciplined Approach to Balancing Quality Requirements; Azad Madni (Intelligent Systems Technology) • 10:00 – 10:30 am: Break • 10:30 am – 12:30 pm: Requirements Volatility; George Friedman (USC), Chair • Process Synchronization and Stabilization; Rick Selby, Northrop Grumman • Disciplined Agility; Rich Turner (SSCI) • Using Anchor Point Milestones; Tom Schroeder, BAE Systems • 12:30 – 1:30 pm: Lunch • 1:30 – 3:30 pm Acquisition and Contracting Mismatches; Rick Selby (NGC), Chair • Acquisition Assessment Analyses; Kristen Baldwin (OSD/AT&T/S&SE) • Commercial Acquisition Practices; Stan Rifkin (Master Systems Inc.) • Space Program Acquisition: Systems Engineering & Programmatic Improvements; Marilee Wheaton (Aerospace Corporation) • 3:30 – 4:00 pm: Break • 4:00 – 5:00 pm: General Discussion: Working Group Formation; Barry Boehm, Chair