This chapter presents the methodological and technical approach, as well as evaluation results, for two semantic matchmakers, COV4SWS.KOM and LOG4SWS.KOM. Both matchmakers operate on WSDL-based service description with SAWSDL annotations. COV4SWS.KOM applies similarity measures from the field of semantic relatedness, namely the metrics by Lin and Resnik. It automatically adapts to varying expressiveness of a service description on different abstraction levels through the utilization of an Ordinary Least Squares (OLS) estimator. LOG4SWS.KOM employs traditional subsumption reasoning, but maps the resulting discrete Degrees of Match (DoMs) to numerical equivalents to allow for the integration with additional similarity measures. As proof of concept, a path length-based measure is applied. The DoM mapping process may either be conducted manually or using an OLS estimator. Both matchmakers participated in the Semantic Service Selection (S3) Contest in 2010, providing very competitive evaluation results across all regarded performance metrics.
