Design and Evaluation of Adverb Palette: A GUI for Selecting Tradeoffs in Multi-objective Optimization Problems

An important part of expressing human intent is identifying acceptable tradeoffs among competing performance objectives. We present and evaluate a set of graphical user interfaces (GUIs), that are designed to allow a human to express intent by expressing desirable tradeoffs. The GUIs require an algorithm that identifies the set of Pareto optimal solutions to the multi-objective decision problem, which means that all the solutions are equally good in the sense that there are no other solutions better for every objective. Given the Pareto set, the GUIs provide different ways for a human to express intent by exploring tradeoffs between objectives; once a tradeoff is selected, the solution is chosen. The GUI designs are applied to interactive human-robot path-selection for a robot in an urban environment, but they can be applied to other tradeoff problems. A user study evaluates GUI designs by requiring users to select a tradeoff that satisfies a specified mission intent. Results of the user study suggest that GUIs designed to support an artist's palette-metaphor can be used to express intent without incurring unacceptable levels of human workload.