Decision Based Design Some Questions David Kazmer University of Massachusetts Amherst

State of Engineering Design Rational design practice is rare –Modeling & analysis capabilities are poor Gross assumptions made –Knowledge of constraints and preferences is typically absent Resulting designs –Designs are far from optimal –Incremental design changes fix known problems –True optimal not known or achieved

Three Questions As Framework 1.Should all design activities, including those that might be intuitive, e.g., brainstorming for the generation of design alternatives, be constructed under a decision theory framework? 2.Is Multiattribute Utility Analysis a useful method in Engineering Design? What is your approach to engineering decision making that involves multiple attributes and multiple decision makers? 3.What are the top research issues for developing DBD approaches to design?

Should all design activities be … under a decision theory framework? No, such a framework can be inappropriate Technical feasibility vs. economic feasibility –Framework acceptance Investment required Designer engagement and control –Availability of information Models, constraints, preferences, expertise Total return on investment

Designers unwilling to accept decision support/automation Designer Engagement and Control LowHigh Low High Investment Required QFD DBD Optimization Designers prefer to be engaged –Everyone suffers from not invented here –Accountability issues Investment –Education –Time –Software

Information Requirements Methodology selection not trivial –Complexity of problem & availability of design options –Knowledge of different methodologies –Potential investment & profits difficult to analyze Current state of information Cost of information Improved performance Benefit of performance –All with uncertainty QFD Net Utility “Optimal” Quality of Information DBD No Method

Should all design activities be … under a decision theory framework? Information Available LowHigh LowQFD High Invest in Model? DBD Assume Result? Decision Impact Interpretation of “should” –Yes, decisions should be rational –No, ends do not always justify rational means

Multiattribute utility analysis useful in engineering design? Consider standard operating procedure: –Deterministic models, objectives, constraints –Use of safety factors & optimization –Little rationality or optimality Yes, MAU useful in reasoning about design –What is functionally important? –How to trade-off attributes? Concept through detailed design stages

Top research issues for developing DBD approaches to design? Research –Design representation –Preference modeling –Handling of uncertainty Development –Systems implementation –Simplification & accessibility of approaches 8 hour seminar with worksheets