Using Pareto Trace to determine system passive value robustness

An important role of system designers is to effectively explore the tradespace of alternatives when making design decisions during concept phase. As systems become more complex, formal methods to enable good design decisions are essential; this can be empowered through a tradespace exploration paradigm. This paper demonstrates the use of the Pareto Trace and associated metrics to identify system alternatives across tradespaces with high degrees of passive value robustness—alternatives that continue to deliver value to stakeholders in spite of changes in needs (attributes) or context. A value-driven tradespace approach is used to represent the baseline performance versus cost of a large number of system alternatives. The classical notion of Pareto Set is extended to identify alternatives and their characteristics that lead to their inclusion in Pareto Sets across changing contexts. Using a low-earth orbiting satellite case example, five types of context changes are used to demonstrate this method: 1) addition or subtraction of attributes; 2) change in the priorities of attributes; 3) change in single attribute utility function shapes; 4) change in multi-attribute utility aggregation function; and 5) addition of new decision maker. This approach demonstrates the ability for system designers to pose questions about assessment of alternatives during early conceptual design. Suggestions for application of Pareto Trace beyond the case example are discussed and presented, including application of a “fuzziness” factor and statistical measures. In particular, distinctions from traditional sensitivity analysis are made, as well as linkages to dynamic analysis for discovery of generalized value robust alternatives.