Partitioning and Matching Tuning of Large Biomedical Ontologies Amir Laadhar1 , Faiza Ghozzi2 , Ryutaro Ichise3 , Imen Megdiche1 , Franck Ravat1 , and Olivier Teste1 1 Toulouse University, IRIT (CNRS/UMR 5505), Toulouse, France {firstname.lastname}@irit.fr 2 University of Sfax, MIRACL, Sfax, Tunisia faiza.ghozzi@isims.usf.tn 3 National Institute of Informatics, Tokyo, Japan ichise@nii.ac.jp 1 Introduction Large biomedical ontologies such as SNOMED CT, NCI, and FMA are exten- sively employed in the biomedical domain. These complex ontologies are based on diverse modelling views and vocabularies. We define an approach that breaks up a large ontology alignment problem into a set of smaller matching tasks. We coupled this approach with an automated tuning process, which generates the adequate thresholds of the available similarity measure for any biomedical matching task. Experiments demonstrate that the coupling between ontology partitioning and threshold tuning outperforms the existing approaches. 2 Partitioning and Matching Tuning of Biomedical Ontologies 2.1 Architecture overview In figure 1, we depict the different stages for ontologies partitioning and threshold tuning. These stages are detailed in the following sections. Fig. 1. Architecture Overview 2.2 Ontologies Partitioning We employ the hierarchical agglomerative clustering technique to divide an on- tology into a set of partitions. This method is based on the equation 1 to compute the structural similarity between the entities of the input ontologies. This equa- tion is inspired by Wu and Palmer [4] similarity measure. The partitioning of every ontology results in a dendrogram. We cut each dendrogram automatically in order to result in a set of partitions. We examine the output of all the possible cuts until finding the first cut which do not result in any isolated partitions. Iso- lated partitions are partitions containing only one entity. We identify the similar partition-pairs through the set of exact matchings between the input ontologies. Dist(ri , lca) × 2 StrcSim(ei,m , ei,n ) = (1) Dist(ei,m , lca) + Dist(ei,n , lca) + Dist(ri , lca) × 2 2 Laadhar et al. 2.3 Threshold tuning The available external knowledge sources represent mediator biomedical ontolo- gies between the two input ontologies. We cross-search the input ontologies and the mediating ontology in order to find synthetic reference alignments. We com- pute the similarity score Sim between all the annotations of thegenerated align- ments. These similarity scores are represented by: simScore = sim1 ,... ,simn . The threshold Th value is deducted fromPsimsimScore using the Equation 2: n sim1 simi Th = (2) 3 Experiments |simScore| In Table 1, we compare our proposed partitioning approach to the currently available partitioning strategies using two OAEI 2017 biomedical data sets: the Anatomy task and the LargeBio small segments tasks. Table 1. Anatomy track partitioning results Precision F-Measure Recall Number of partitions Proposed approach 0.945 0.883 0.829 57/57 SeeCOnt [3] 0.951 0.863 0.789 ND Falcon [2] 0.964 0.730 0.591 139/119 Alsayed et al. [1] 0.975 0.753 0.613 84/80 We employed UBERON as an external biomedical knowledge for deriving synthetic reference alignments. We use ISUB similarity measure to compute the similarity scores between the derived mappings. In Table 2, we illustrate the accuracy of the partitioning approach with the deduced thresholds. Table 2. Accuracy and derived thresholds for Anatomy and LargeBio tracks Precision F-Measure Recall Derived Threshold Anatomy 0.945 0.883 0.829 0.91 FMA-NCI 0.957 0.870 0.789 0.69 FMA-SNOMED 0.860 0.674 0.554 0.75 SNOMED-NCI 0.911 0.697 0.564 0.85 4 Conclusion and Future Work As future work, we intend to automate all the matching tuning process while focusing on different type of heterogeneity applied over the partitions-pairs. References 1. Algergawy, Alsayed, Sabine Massmann, and Erhard Rahm. ”A clustering-based ap- proach for large-scale ontology matching.” East European Conference on Advances in Databases and Information Systems. Springer, Berlin, Heidelberg, (2011). 2. Hu, Wei, Yuzhong Qu, and Gong Cheng. ”Matching large ontologies: A divide-and- conquer approach.” Data Knowledge Engineering 67.1, (2008). 3. Algergawy, Alsayed, Samira Babalou, Mohammad J. Kargar, and S. Hashem Davarpanah. ”Seecont: A new seeding-based clustering approach for ontology match- ing.” In East European Conference on Advances in Databases and Information Sys- tems, Springer (2015). 4. Wu, Zhibiao, and Martha Palmer. ”Verbs semantics and lexical selection.” In Pro- ceedings of the 32nd annual meeting on Association for Computational Linguistics, (1994).