Georgi Grazhdanski


2023

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FMI-SU at SemEval-2023 Task 7: Two-level Entailment Classification of Clinical Trials Enhanced by Contextual Data Augmentation
Sylvia Vassileva | Georgi Grazhdanski | Svetla Boytcheva | Ivan Koychev
Proceedings of the 17th International Workshop on Semantic Evaluation (SemEval-2023)

The paper presents an approach for solving SemEval 2023 Task 7 - identifying the inference relation in a clinical trials dataset. The system has two levels for retrieving relevant clinical trial evidence for a statement and then classifying the inference relation based on the relevant sentences. In the first level, the system classifies the evidence-statement pairs as relevant or not using a BERT-based classifier and contextual data augmentation (subtask 2). Using the relevant parts of the clinical trial from the first level, the system uses an additional BERT-based classifier to determine whether the relation is entailment or contradiction (subtask 1). In both levels, the contextual data augmentation is showing a significant improvement in the F1 score on the test set of 3.7% for subtask 2 and 7.6% for subtask 1, achieving final F1 scores of 82.7% for subtask 2 and 64.4% for subtask 1.