Jinwook Choi


Feature Difference Makes Sense: A medical image captioning model exploiting feature difference and tag information
Hyeryun Park | Kyungmo Kim | Jooyoung Yoon | Seongkeun Park | Jinwook Choi
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics: Student Research Workshop

Medical image captioning can reduce the workload of physicians and save time and expense by automatically generating reports. However, current datasets are small and limited, creating additional challenges for researchers. In this study, we propose a feature difference and tag information combined long short-term memory (LSTM) model for chest x-ray report generation. A feature vector extracted from the image conveys visual information, but its ability to describe the image is limited. Other image captioning studies exhibited improved performance by exploiting feature differences, so the proposed model also utilizes them. First, we propose a difference and tag (DiTag) model containing the difference between the patient and normal images. Then, we propose a multi-difference and tag (mDiTag) model that also contains information about low-level differences, such as contrast, texture, and localized area. Evaluation of the proposed models demonstrates that the mDiTag model provides more information to generate captions and outperforms all other models.


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Connecting Distant Entities with Induction through Conditional Random Fields for Named Entity Recognition: Precursor-Induced CRF
Wangjin Lee | Jinwook Choi
Proceedings of the Seventh Named Entities Workshop

This paper presents a method of designing specific high-order dependency factor on the linear chain conditional random fields (CRFs) for named entity recognition (NER). Named entities tend to be separated from each other by multiple outside tokens in a text, and thus the first-order CRF, as well as the second-order CRF, may innately lose transition information between distant named entities. The proposed design uses outside label in NER as a transmission medium of precedent entity information on the CRF. Then, empirical results apparently demonstrate that it is possible to exploit long-distance label dependency in the original first-order linear chain CRF structure upon NER while reducing computational loss rather than in the second-order CRF.


Extracting Distinctive Features of Swine (H1N1) Flu through Data Mining Clinical Documents
Heekyong Park | Jinwook Choi
Proceedings of the 2010 Workshop on Biomedical Natural Language Processing