Goal of design Create a system that fulfills some need while efficiently utilizing resources

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Capturing Unarticulated Value: System Properties and Multi-Attribute Tradespace Exploration Presented By Adam Ross, ESD PhD Candidate MIT/MITRE Workshop March

1 Capturing Unarticulated Value: System Properties and Multi-Attribute Tradespace Exploration Presented By Adam Ross, ESD PhD Candidate MIT/MITRE Workshop March 4, 2005 Committee: Daniel Hastings (Chair), Deborah Nightingale, Olivier de Weck, Thomas Allen 2005 Massachusetts Institute of Technology Adam Ross/

2 Goal of design Create a system that fulfills some need while efficiently utilizing resources Question How can a system designer cope with poorly defined needs? 2005 Massachusetts Institute of Technology Adam Ross/

3 Dual-SM Aero/Astro, TPP 2003 MATE-CON Overview Architecture Exploration Design Evaluation System Design(s) MATE-CON is Need Identification Architecture Evaluation Design Exploration Level 0 Level 1 Level 2 A Decision Maker preference-directed tradespace exploration process Robust to changes and concepts A formalized framework A flexible philosophy Utility Firm Designer External Stakeholders Policy, etc. Organizational Goals designs Contracts Requirements value A Policy, etc. Customer Operational Strategy uses User Decision Makers B D C Identify Need Define Mission Define Scope Identify all relevant decision makers Identify Constraints Propose Attribute Definitions (USER) Nail down attribute definitions (USER) Propose Attribute Definitions (CUSTOMER Nail down attribute definitions (CUSTOME Propose Attribute Definitions (FIRM) Nail down attribute definitions (FIRM) Concept generation Utility interview (USER) Utility verification and validation (USER) Utility interview (CUSTOMER) Utility verification and validation (CUSTOM Utility interview (FIRM) Utility verification and validation (FIRM) Propose Design Variables Nail down Design Variables Map Design variable to attributes Decompose code (develop software archit Organization formation (software teams) Identify I/O for entire simulation Write Model translation from DV to Att Integrate model Enumerate tradespace Navigate enumerated tradespace (intellige Run simulation (calculate attributes) Run Utility function Verify Output Analyze output Perform sensitivity analysis (constants/con Perform sensitivity analysis (utility function Refine tradespace Rerun simulation/utility function Analyze output Locate frontier Select reduced solution set Show to DM(s) Define stakeholder tradeoff function Select design(s) for concurrent design Set selected design as baseline for CE Develop higher fidelity CE models Perform concurrent design trades Converge on final design(s) Show to DM(s) Select final design(s) Formal Framework Lifecycle Cost ($M) Tradespace Solution Spaces 2005 Massachusetts Institute of Technology Adam Ross/ E

4 Capturing System Properties: Tradespace ilities Q: What if Decision Maker(s) cannot/do not articulate everything that will result in VALUE? Pareto surface P1 Flexibility 0.66 P2 Agility 0.54 P3 Robustness 0.88 P4 P5 P6 P7 P8 P9 P10 P11 P12 Failsafe Adaptability Scalability Modularity Safety Durability Sustainability Quality Reliability Do these ilities apply to entire tradespace, or to each solution? 1 value? C D Design E P13 Reparability P14 Maintainability 0.11 B Utility 0.99 A: Attempt to assess system properties From Ross, TBD A 2005 Massachusetts Institute of Technology Adam Ross/ Lifecycle Cost ($M)

5 Articulated versus Unarticulated Value Articulated Value Traditional requirements Objectives, attributes Desirements Must haves Unarticulated Value Fuzzy desires, objectives Emergent applications Good to haves System properties??? A A A flexible system is is a good thing, but what is is it it and how much? 2005 Massachusetts Institute of Technology Adam Ross/

6 System Context: Value Lenses Static View Constraints Dynamic View Structural Metrics Operational Metrics Delay Decisional Inputs System Outputs Experienced Value Value System Boundary 2005 Massachusetts Institute of Technology Adam Ross/

7 Tradespace Exploration: Avoiding Point Designs Differing types of trades Utility(t) 1. Local point solution trades 2. Frontier subset solutions 3. Frontier solution set 4. Full tradespace exploration 4b. Tradespace ilities (NEW) Cost(t) Design i = {X 1, X 2, X 3,,X j } Tradespace exploration enables big picture understanding 2005 Massachusetts Institute of Technology Adam Ross/

8 Flexibility Over Time: SBR Technology and Programmatic Flexibility Over Time for Space-Based Radar Transitionability relates to distance between architectures Transition costs vary widely based on transition path Pareto Front may not provide best answers Optimality not defined when fitness function changes over time Number of Transition Possibilities: 2002 to 2005 (decreasing altitude e) Utility Cost of flexibility? Life cycle Cost ($B) From Shah, Massachusetts Institute of Technology Adam Ross/ Additional tech transitions possible based on investment SBR

9 Example Tradespace Change: Pareto Set Shift What happens when preferences change? Multiattribute Utility (using MIST2 data) Multiattribute Utility (using HAND2 data) year life cycle cost ($b) year life cycle cost ($b) From Spaulding, 2003 Dynamic tradespaces may reveal dynamic properties From Spaulding, Massachusetts Institute of Technology Adam Ross/

10 Research Design: Experiments Computer experiments Isolate ilities Utilize past data (X-TOS, B-TOS, SpaceTug) Experiment set #1: Dynamic context Question: How is a tradespace affected when articulated value changes? Two classes of value changes: Single DM changing over time Addition of new/different DM Post-process X-TOS dataset Vary input preferences, collect statistics on output tradespace, including Pareto Set 0.8 Original 0.8 Revised Optimized solutions may may be be poor poor choices under under changing value value Massachusetts Institute of Technology Adam Ross/

11 Research Questions New research questions: 1. What are the relationships between flexibility, adaptability, robustness, and scalability for space systems and how do they relate to unarticulated value? 2. How can these ilities be quantified and/or used as decision metrics when exploring tradespaces during Conceptual Design? Questions guide exploratory research design Inheritance, Theory, Experiments, Case studies 2005 Massachusetts Institute of Technology Adam Ross/

12 Expected Findings Contributions of research Concrete quantification of flexibility, robustness, adaptability, and scalability in a value-centric tradespace framework Insight into how unarticulated value may be assessed Useful and expanded process/framework for Conceptual Design trade studies Suggestions for future work 2005 Massachusetts Institute of Technology Adam Ross/

13 Questions? 2005 Massachusetts Institute of Technology Adam Ross/

SEAri Short Course Series

SEAri Short Course Series Course: Lecture: Author: PI.27s Value-driven Tradespace Exploration for System Design Lecture 1: Why Use Tradespace Exploration? Adam Ross and Donna Rhodes Lecture Number: SC-2010-PI27s-1-1