Top Down Topic Hierarchy Constructed by the Hierarchical Predicate-based K-Means clustering Algorithm.

<p>The top down topic hierarchy with three levels has seven topics at the third level. The number assigned to the edges indicates the distribution of predicates to its child node. The sum of the numbers should be one (e.g., 0.17 + 0.83 at the top level). A color is assigned to each domain as follows: DrugBank: Red; HGNC: Pink; MGI: Green; PharmGKB: Cyan; ClinicalTrials: Yellow; OMIM: Sky Blue; SIDER: Gray; KEGG: Orange; CTD: Magenta.