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OBJECTIVES To quantify semantic inconsistency in UMLS concepts from the perspective of their hierarchical relations and to show through examples how semantically-inconsistent concepts can help reveal erroneous synonymy relations. METHODS Inconsistency is defined in reference to concepts from the UMLS Metathesaurus. Consistency is evaluated by comparing(More)
We study finding similar or diverse solutions of a given computational problem, in answer set programming, and introduce offline methods and online methods to compute them using answer set solvers. We analyze the computational complexity of some problems that are related to finding similar or diverse solutions , and show the applicability and effectiveness(More)
We present new methods to efficiently answer complex queries over biomedical ontologies and databases considering the relevant parts of these knowledge resources, and to generate shortest explanations to justify these answers. Both algorithms rely on the high-level representation and efficient solvers of Answer Set Programming. We apply these algorithms to(More)
  • Research Showcase, Cmu, Heng-Tze Cheng, Ying Zhang, Ole Mengshoel, Dan Siewiorek +97 others
  • 2016
The mission of the research presented in this thesis is to give computers the power to sense and react to human activities. Without the ability to sense the surroundings and understand what humans are doing, computers will not be able to provide active, timely, appropriate, and considerate services to the humans. To accomplish this mission, the work stands(More)
For some problems with many solutions, like planning and phylogeny reconstruction, one way to compute more desirable solutions is to assign weights to solutions, and then pick the ones whose weights are over (resp. below) a threshold. This paper studies computing weighted solutions to such problems in Answer Set Programming. We investigate two sorts of(More)
We introduce a new method to find semantic inconsistencies (i.e., concepts with erroneous synonymity) in the Unified Medical Language System (UMLS). The idea is to identify the inconsistencies by comparing the semantic groups of hierarchically-related concepts using Answer Set Programming. With this method, we identified several inconsistent concepts in(More)
Recent advances in health and life sciences have led to generation of a large amount of data. To facilitate access to its desired parts, such a big mass of data has been represented in structured forms, like biomedical ontologies. On the other hand, representing ontologies in a formal language, constructing them independently from each other and storing(More)
For some computational problems (e.g., product configuration, planning, diagnosis, query answering, phylogeny reconstruction) computing a set of similar/diverse solutions may be desirable for better decision-making. With this motivation, we have studied several decision/optimization versions of this problem in the context of Answer Set Programming (ASP),(More)
For some problems with many solutions, like planning and phylogeny reconstruction, one way to compute more desirable solutions is to assign weights to solutions, and then pick the ones whose weights are over (resp. below) a threshold. This paper studies computing weighted solutions to such problems in Answer Set Programming. We investigate two sorts of(More)