What are some potential pitfalls of ontology-based querying?
Expanding user searches to subparts is sometimes problematic if the ontology was not designed with a specific use case (such as searching for medical articles) in mind. For instance, in FMA, anatomical part hierarchies are modeled from the level of an organ down to the cellular level. It is not very useful if the user searches for lung and finds articles about the cell. Of course, lungs are composed of cells, but so are all other organs. To solve this problem, we return queries ranked by the length of the chain of reasoning it took to derive that a part (such as a cell) is a subpart of the queried part (such as a lung). As the semantic distance grows between concepts in an ontology, the likelihood that they are relevant decreases. We use this to rank our returned results. We also group results by matching search terms, so users can easily discard results that they deem irrelevant.
