In this article we present three similarity measures based on ontologies that are used to allow data mining in case of very sparse data. With the use of semantic knowledge associated to data sources we can aggregate data from similar sources and use that aggregated data to train a machine learning model. This article focuses on the ontology-based similarity measures that are required to compare data sources. We evaluate our similarity measures using a custom ontology created for fashion specific data and show that it is possible to identify similar data sources and gradually assign them similarity values.

If knowledge such as classification rules are extracted from sample data in a distributed way, it may be necessary to combine or fuse these rules. In a conventional approach this would typically be done either by combining the classifiers' outputs (e.g., in form of a classifier ensemble) or by combining the sets of classification rules (e.g., by weighting them individually). In this paper, we introduce a new way of fusing classifiers at the level of parameters of classification rules. This technique is based on the use of probabilistic generative classifiers using multinomial distributions for categorical input dimensions and multivariate normal distributions for the continuous ones. That means, we have distributions such as Dirichlet or normal-Wishart distributions over parameters of the classifier. We refer to these distributions as hyperdistributions or second-order distributions. We show that fusing two (or more) classifiers can be done by multiplying the hyperdistributions of the parameters and derive simple formulas for that task. Properties of this new approach are demonstrated with a few experiments. The main advantage of this fusion approach is that the hyperdistributions are retained throughout the fusion process. Thus, the fused components may, for example, be used in subsequent training steps (online training).

Intelligent agents often have the same or similar tasks and sometimes they cooperate to solve a given problem. These agents typically know how to observe their local environment and how to react on certain observations, for instance, and this knowledge may be represented in form of rules. However, many environments are dynamic in the sense that from time to time novel rules are required or old rules become obsolete. In this article we propose and investigate new techniques for knowledge acquisition by novelty detection and reaction as well as obsoleteness detection and reaction that an agent may use for self-adaptation to new situations. For that purpose we consider classifiers based on probabilistic rules. Premises of new rules are learned autonomously while conclusions are either obtained from human experts or from other agents which have learned appropriate rules in the past. By means of knowledge exchange, agents will efficiently be enabled to cope with situations they were not confronted with before. This kind of collaborative intelligence follows the human archetype: Humans are able to learn from each other by communicating learned rules. We demonstrate some properties of the knowledge acquisition techniques using artificial data as well as data from the field of intrusion detection.