Bayesian networks: a combined tuning heuristic

One of the issues in tuning an output probability of a Bayesian network by changing multiple parameters is the relative amount of the individual parameter changes. In an existing heuristic parameters are tied such that their changes induce locally a maximal change of the tuned probability. This heuristic, however, may reduce the attainable values of the tuned probability considerably. In another existing heuristic parameters are tied such that they simultaneously change in the entire interval <0,1>. The tuning range of this heuristic will in general be larger then the tuning range of the locally optimal heuristic. Disadvantage, however, is that knowledge of the local optimal change is not exploited. In this paper a heuristic is proposed that is locally optimal, yet covers the larger tuning range of the second heuristic. Preliminary experiments show that this heuristic is a promising alternative.