π€ AI Summary
This work addresses the challenge in iterative interaction design where the benefits of prototype refinement are often difficult to balance against diverse and asymmetric fabrication costs, thereby limiting effective exploration of the design space. We propose the first approach that explicitly incorporates designersβ estimated prototype costs into a Bayesian optimization framework by lightly modifying the acquisition function to enable cost-aware sampling. Our method achieves comparable utility at approximately 70% of the cost or, under strict budget constraints, delivers up to three times the performance of baseline methods. A user study with twelve participants further confirms its significant advantages in real-world design tasks, enhancing both the practicality and efficiency of Bayesian optimization for human-computer interaction prototyping.
π Abstract
Deciding which idea is worth prototyping is a central concern in iterative design. A prototype should be produced when the expected improvement is high and the cost is low. However, this is hard to decide, because costs can vary drastically: a simple parameter tweak may take seconds, while fabricating hardware consumes material and energy. Such asymmetries, can discourage a designer from exploring the design space. In this paper, we present an extension of cost-aware Bayesian optimization to account for diverse prototyping costs. The method builds on the power of Bayesian optimization and requires only a minimal modification to the acquisition function. The key idea is to use designer-estimated costs to guide sampling toward more cost-effective prototypes. In technical evaluations, the method achieved comparable utility to a cost-agnostic baseline while requiring only ${\approx}70\%$ of the cost; under strict budgets, it outperformed the baseline threefold. A within-subjects study with 12 participants in a realistic joystick design task demonstrated similar benefits. These results show that accounting for prototyping costs can make Bayesian optimization more compatible with real-world design projects.