In this paper, we focus on a novel knowledge reuse scenario where the knowledge in the source schema needs to be translated to a semantically heterogeneous target schema. We refer to this task as "knowledge translation" (KT). Unlike data translation and transfer learning, KT does not require any data from the source or target schema. We adopt a probabilistic approach to KT by representing the knowledge in the source schema, the mapping between the source and target schemas, and the resulting knowledge in the target schema all as probability distributions, specially using Markov random fields and Markov logic networks. Given the source knowledge and mappings, we use standard learning and inference algorithms for probabilistic graphical models to find an explicit probability distribution in the target schema that minimizes the Kullback-Leibler divergence from the implicit distribution. This gives us a compact probabilistic model that represents knowledge from the source schema as well as possible, respecting the uncertainty in both the source knowledge and the mapping. In experiments on both propositional and relational domains, we find that the knowledge obtained by KT is comparable to other approaches that require data, demonstrating that knowledge can be reused without data.
Deductive knowledge translation @cite_7 essentially tries to solve the same problem, but it only considers deterministic knowledge and mappings. Our KT work can handle knowledge and mappings with uncertainty, which is more general than the deterministic scenario deductive knowledge translation @cite_7 can handle.
@cite_7
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Considering data size and privacy concerns in a distributed setting, it is neither desirable nor feasible to translate data from one resource to another in data mining. Rather, it makes more sense to first mine knowledge from one data resource and then translate the discovered knowledge (models) to another for knowledge reuse. Although there have been successful research efforts in knowledge transfer, the knowledge translation problem in the semantically heterogenous scenario has not been addressed adequately. In this paper, we first propose to use Semantic Web ontologies to represent rule-based knowledge to make the knowledge computer "translatable". Instead of an inductive learning approach, we treat knowledge translation as a deductive inference. We elaborate a translation method with both the forward and backward chaining to address the asymmetry of translation. We show the effectiveness of our knowledge translation method in decision tree rules and association rules mined from sports and gene data respectively. In a more general context, this work illustrates the promise of a novel research which leverages ontologies and Semantic Web techniques to extend the knowledge transfer in data mining to the semantically heterogeneous scenario.