AMHARIC WORD SENSE DISAMBIGUATION USING TRANSFER  LEARNING

NEIMA, MOSSA AHMED

dc.contributor.author	NEIMA, MOSSA AHMED
dc.date.accessioned	2022-12-31T06:44:10Z
dc.date.available	2022-12-31T06:44:10Z
dc.date.issued	2022-08
dc.identifier.uri	http://ir.bdu.edu.et/handle/123456789/14786
dc.description.abstract	Word sense disambiguation (WSD) plays an important role in different NLP applications such as information extraction, information retrieval, machine translation, and lexicography. The manual disambiguation process by humans is tedious, prone to errors, expensive, and time-consuming. Recent research in Amharic WSD used mostly handcrafted rules. Such works do not help to learn different representations of the target word (ambiguous word) from data automatically. Moreover, such a manual disambiguation approach looks at a limited length of surrounding words from the sentence. The main drawback of previous works is that the sense of the word will not be detected from the synset list unless the word is explicitly mentioned. Our study explores and designs the Amharic word sense disambiguation model by employing transformer-based contextual embeddings. More specifically, we have exploited the different operations provided by the transformer models, namely AmRoBERTa. As there is no standard sense-tagged Amharic text dataset for the Amharic WSD task, we first compiled 800 ambiguous words from different sources, including the Amharic dictionary, Amharic textbooks (Grade 7-12), and the Abissinica online dictionary. Furthermore, we collect more than 33k sentences that contain those ambiguous words. The 33k sentences are used to finetune our transformer-based RoBERTa model (AmRoBERTa). We conduct two types of annotation for our WSD experiments. First, using linguistic experts, we annotate 10k sentences for 7 types of word relations (synonymy, hyponymy, hypernymy, meronomy, holonomy, toponymy, and homonymy). For the WSD disambiguation experiment, we first choose 10 target words and annotate a total of 1000 sentences with their correct sense using the WebAnno annotation tool. Each sentence with one target ambiguous word is annotated by two users and one curator vii (adjudicator). As preparing glosses for each sense is time taking, we prepare 100 glosses for the selected 10 targets. We conduct two main experiments, word relationship classification using the CNN, BiLSTM, and BERT models and WDS disambiguation using the AmRoBERTa model with sentence similarity measures. For the classification task, the CNN, Bi-LSTM, and BERTbased classification models achieve an accuracy of 90%, 88%, and 93% respectively. For the WSD task, we have employed the FLAIR document embedding framework to embed the target sentences and glosses separately. We then compute the similarity of the target sentence with the glosses embedding. The gloss with the higher score disambiguates the target sentence. Our model was able to achieve an F1 score of 71%. Due to time constraints and the lack of Amharic WordNet, we could not experiment with a large number of training datasets. In the future, we plan to at least compile glosses for the 1000 sentences annotated using WebAnno and report the performance. Keywords: Word Sense Disambiguation, Transfer Learning, Neural network, pre-trained Language Model, Natural Language Preprocessing, Morphological Analyzer, Amharic WSD.	en_US
dc.language.iso	en_US	en_US
dc.subject	INFORMATION TECHNOLOGY	en_US
dc.title	AMHARIC WORD SENSE DISAMBIGUATION USING TRANSFER LEARNING	en_US
dc.type	Thesis	en_US