Balancing User Interaction and Control in Bayesian Network Structure Learning

Abstract. In this paper we present a study based on an evolutionary framework to explore what would be a reasonable compromise between interaction and automated optimisation in finding possible solutions for a complex problem, namely the learning of Bayesian network structures, an NP-hard problem where user knowledge can be crucial to distinguish among solutions of equal fitness but very different physical meaning. Even though several classes of complex problems can be effectively tack-led with Evolutionary Computation, most possess qualities that are dif-ficult to directly encode in the fitness function or in the individual’s genotype description. Expert knowledge can sometimes be used to inte-grate the missing information, but new challenges arise when searching for the best way to access it: full human interaction can lead to the well-known problem of user-fatigue, while a completely automated evo-lutionary process can miss important contributions by the expert. For our study, we developed a GUI-based prototype application that lets an expert user guide the evolution of a network by alternating between fully-interactive and completely automatic steps. Preliminary user tests were able to show that despite still requiring some improvements with regards to its efficiency, the proposed approach indeed achieves its goal of delivering satisfying results for an expert user