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Biomedical subjects

Meliha Yetisgen-Yildiz

Publications and source records attributed to Meliha Yetisgen-Yildiz.

3 recordsLinked to original sources

Using statistical and knowledge-based approaches for literature-based discovery.

The explosive growth in biomedical literature has made it difficult for researchers to keep up with advancements, even in their own narrow specializations. While researchers formulate new hypotheses to test, it is very important for them to identify connections to their work from other parts of the literature. However, the current volume of information has become a great barrier for this task and new automated tools are needed to help researchers identify new knowledge that bridges gaps across distinct sections of the literature. In this paper, we present a literature-based discovery system called LitLinker that incorporates knowledge-based methodologies with a statistical method to mine the biomedical literature for new, potentially causal connections between biomedical terms. We demonstrate LitLinker's ability to capture novel and interesting connections between diseases and chemicals, drugs, genes, or molecular sequences from the published biomedical literature. We also evaluate LitLinker's performance by using the information retrieval metrics of precision and recall.

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The effect of feature representation on MEDLINE document classification.

This work explores the effect of text representation techniques on the overall performance of medical text classification. To accomplish this goal, we developed a text classification system that supports the very basic word representation (bag-of-words) and the more complex medical phrase representation (bag-of-phrases). We also combined word and phrase representations (hybrid) for further analysis. Our system extracts medical phrases from text by incorporating a medical knowledge base and natural language processing techniques. We conducted experiments to evaluate the effects of different representations by measuring the change in classification performance with MEDLINE documents from the OHSUMED dataset. We measured classification performance with information retrieval metrics; precision (p), recall (r), and F1-score (F1). In our experiments, we achieved better classification performance with the hybrid approach (p=0.87, r=0.46, F1=0.60) compared to the bag-of-words approach (p=0.85, r=0.44, F1=0.58) and the bag-of-phrases approach (p=0.87, r=0.42, F1=0.57).

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A study of biomedical concept identification: MetaMap vs. people.

Although huge amounts of unstructured text are available as a rich source of biomedical knowledge, to process this unstructured knowledge requires tools that identify concepts from free-form text. MetaMap is one tool that system developers in biomedicine have commonly used for such a task, but few have studied how well it accomplishes this task in general. In this paper, we report on a study that compares MetaMap's performance against that of six people. Such studies are challenging because the task is inherently subjective and establishing consensus is difficult. Nonetheless, for those concepts that subjects generally agreed on, MetaMap was able to identify most concepts, if they were represented in the UMLS. However, MetaMap identified many other concepts that peo-ple did not. We also report on our analysis of the types of failures that MetaMap exhibited as well as trends in the way people chose to identify concepts.

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