title: Mining Relation Reversals in the Evolution of SNOMED CT Using MapReduce.
abstract: Relation reversals in ontological systems refer to such patterns as a path from concept A to concept B in one version becoming a path with the position of A and B switched in another version. We present a scalable approach, using cloud computing, to systematically extract all hierarchical relation reversals among 8 SNOMED CT versions from 2009 to 2014. Taking advantage of our MapReduce algorithms for computing transitive closure and large-scale set operations, 48 reversals were found through 28 pairwise comparison of the 8 versions in 18 minutes using a 30-node local cloud, to completely cover all possible scenarios. Except for one, all such reversals occurred in three sub-hierarchies: Body Structure, Clinical Finding, and Procedure. Two (2) reversal pairs involved an uncoupling of the pair before the is-a coupling is reversed. Twelve (12) reversal pairs involved paths of length-two, and none (0) involved paths beyond length-two. Such reversals not only represent areas of potential need for additional modeling work, but also are important for identifying and handling cycles for comparative visualization of ontological evolution.
authors: Department of EECS, Case Western Reserve University, Cleveland, OH, USA ; Division of Medical Informatics, Case Western Reserve University, Cleveland, OH, USA.
authors: Shiqiang
authors: S
authors: Tao
authors: Department of EECS, Case Western Reserve University, Cleveland, OH, USA.
authors: Licong
authors: L
authors: Cui
authors: Department of EECS, Case Western Reserve University, Cleveland, OH, USA.
authors: Wei
authors: W
authors: Zhu
authors: Department of EECS, Case Western Reserve University, Cleveland, OH, USA.
authors: Mengmeng
authors: M
authors: Sun
authors: National Library of Medicine, Bethesda, MD 20892, USA.
authors: Olivier
authors: O
authors: Bodenreider
authors: Department of EECS, Case Western Reserve University, Cleveland, OH, USA ; Division of Medical Informatics, Case Western Reserve University, Cleveland, OH, USA.
authors: Guo-Qiang
authors: GQ
authors: Zhang