Acronyms are the short forms of phrases that facilitate conveying lengthy sentences in documents and serve as one of the mainstays of writing. Due to their importance, identifying acronyms and corresponding phrases (i.e., acronym identification (AI)) and finding the correct meaning of each acronym (i.e., acronym disambiguation (AD)) are crucial for text understanding. Despite the recent progress on this task, there are some limitations in the existing datasets which hinder further improvement. More specifically, limited size of manually annotated AI datasets or noises in the automatically created acronym identification datasets obstruct designing advanced highperforming acronym identification models. Moreover, the existing datasets are mostly limited to the medical domain and ignore other domains. In order to address these two limitations, we first create a manually annotated large AI dataset for scientific domain. This dataset contains 17,506 sentences which is substantially larger than previous scientific AI datasets. Next, we prepare an AD dataset for scientific domain with 62,441 samples which is significantly larger than previous scientific AD dataset. Our experiments show that the existing state-of-the-art models fall far behind human-level performance on both datasets proposed by this work. In addition, we propose a new deep learning model which utilizes the syntactical structure of the sentence to expand an ambiguous acronym in a sentence. The proposed model outperforms the state-of-the-art models on the new AD dataset, providing a strong baseline for future research on this dataset 1 .
IntroductionAcronyms are shortened forms of a longer phrase. As a running example, in the sentence "The main key performance indicator, herein referred to as KPI, is the E2E throughput" there are two acronyms KPI and E2E. Also, the acronym KPI refers to the phrase key performance indicator (a.k.a. the long form of the acronym KPI). In written language, acronyms are prevalent in technical documents that helps to avoid the repetition of long and cumbersome terms, thus saving text space. For instance, about 15% of PubMed queries include abbreviations, and about 14.8% of all tokens in a clinical note dataset are abbreviations (Islamaj Dogan et al., 2009;Xu et al., 2007;Jin et al., 2019).Considering the widespread use of acronyms in texts, a text processing application, such as question answering or document retrieval, should be able to correctly process the acronyms in the text and find their meanings. To this end, two sub-tasks should be solved: Acronym Identification (AI): to find the acronyms and the phrases that have been abbreviated by the acronyms in the document. In the running example, the acronyms KPI and E2E and the phrase key performance indicator should be extracted. Acronym Disambiguation (AD): to find the right meaning for a given acronym in text. In the running example, the systems should be able to find the right meanings of the two acronyms KPI and E2E. Note that while the meaning of KPI is found in the senten...