Generalizing over Long Tail Concepts for Medical Term Normalization

Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing, pages 900 - 913 December 7-11, 2022 ©2022 Association for Computational Linguistics Cross-document Event Coreference Search: Task, Dataset and Modeling Alon Eirew1,2 Avi Caciularu1 Ido Dagan1 1Bar Ilan University, Ramat-Gan, Israel alon.eirew@intel.com2Intel Labs, Israel avi.c33@gmail.com dagan@cs.biu.ac.il Abstract The task of Cross-document Coreference Reso- lution has been traditionally formulated as re- quiring to identify all coreference links across a given set of documents. We propose an appeal- ing, and often more applicable, complementary set up for the task – Cross-document Corefer- ence Search, focusing in this paper on event coreference. Concretely, given a mention in context of an event of interest, considered as a query, the task is to find all coreferring men- tions for the query event in a large document collection. To support research on this task, we create a corresponding dataset, which is derived from Wikipedia while leveraging annotations in the available Wikipedia Event Coreference dataset (WEC-Eng). Observing that the coref- erence search setup is largely analogous to the setting of Open Domain Question Answering, we adapt the prominent Deep Passage Retrieval (DPR) model to our setting, as an appealing baseline. Finally, we present a novel model that integrates a powerful coreference scoring scheme into the DPR architecture, yielding im- proved performance. 1 Introduction Cross-Document Event Coreference (CDEC) res- olution is the task of identifying clusters of text mentions, across multiple texts, that refer to the same event. For example, consider the following two underlined event mentions from the WEC-Eng CDEC dataset (Eirew et al., 2021): 1. ...On 14 April 2010, an earthquake struck the prefecture, registering a magnitude of 6.9 (USGS, EMSC) or 7.1 (Xinhua). It originated in the Yushu Tibetan Autonomous Prefecture... 2. ...a school mostly for Tibetan orphans in Chindu County, Qinghai, after the 2010 Yushu earthquake destroyed the old school... Both event mentions refer to the same earth- quake, as can be determined by the shared event Figure 1: Example of Coreference Search. Provided with a query passage containing a mention of interest, a coreference search system retrieves from a large corpus the best candidate passages containing mentions core- ferring with the query. arguments (2010, Yushu, Tibetan). In event coref- erence resolution, the goal is to cluster event men- tions that refer to the same event, whether within a single document or across a document collection. Currently, with the growing number of doc- uments describing real-world events and event- oriented information, the need for efficient meth- ods for accessing such information is apparent. Successful and efficient identification, clustering, and access to event-related information, may be beneficial for a broad range of applications at the multi-text level, that need to match and inte- grate information across documents, such as multi- document summarization (Falke et al., 2017; Liao et al., 2018), multi-hop question answering (Dhin- gra et al., 2018; Wang et al., 2019) and Knowledge Base Population (KBP) (Lin et al., 2020). Currently, the CDEC task, as formed in corre- sponding datasets, is intended …

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