Eitan Wagner


2024

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Zero-shot Trajectory Mapping in Holocaust Testimonies
Eitan Wagner | Renana Keydar | Omri Abend
Proceedings of the First Workshop on Holocaust Testimonies as Language Resources (HTRes) @ LREC-COLING 2024

This work presents the task of Zero-shot Trajectory Mapping, which focuses on the spatial dimension of narratives. The task consists of two parts: (1) creating a “map” with all the locations mentioned in a set of texts, and (2) extracting a trajectory from a single testimony and positioning it within the map. Following recent advances in context length capabilities of large language models, we propose a pipeline for this task in a completely unsupervised manner, without the requirement of any type of labels. We demonstrate the pipeline on a set of ≈ 75 testimonies and present the resulting map and samples of the trajectory. We conclude that current long-range models succeed in generating meaningful maps and trajectories. Other than the visualization and indexing, we propose future directions for adaptation of the task as a step for dividing testimony sets into clusters and for alignment between parallel parts of different testimonies.

2023

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Event-Location Tracking in Narratives: A Case Study on Holocaust Testimonies
Eitan Wagner | Renana Keydar | Omri Abend
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing

This work focuses on the spatial dimension of narrative understanding and presents the task of event-location tracking in narrative texts. The task intends to extract the sequence of locations where the narrative is set through its progression. We present several architectures for the task that seeks to model the global structure of the sequence, with varying levels of context awareness. We compare these methods to several baselines, including the use of strong methods applied over narrow contexts. We also develop methods for the generation of location embeddings and show that learning to predict a sequence of continuous embeddings, rather than a string of locations, is advantageous in terms of performance. We focus on the test case of Holocaust survivor testimonies. We argue for the moral and historical importance of studying this dataset in computational means and that it provides a unique case of a large set of narratives with a relatively restricted set of location trajectories. Our results show that models that are aware of the larger context of the narrative can generate more accurate location chains. We further corroborate the effectiveness of our methods by showing similar trends from experiments on an additional domain.

2022

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Topical Segmentation of Spoken Narratives: A Test Case on Holocaust Survivor Testimonies
Eitan Wagner | Renana Keydar | Amit Pinchevski | Omri Abend
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing

The task of topical segmentation is well studied, but previous work has mostly addressed it in the context of structured, well-defined segments, such as segmentation into paragraphs, chapters, or segmenting text that originated from multiple sources. We tackle the task of segmenting running (spoken) narratives, which poses hitherto unaddressed challenges. As a test case, we address Holocaust survivor testimonies, given in English. Other than the importance of studying these testimonies for Holocaust research, we argue that they provide an interesting test case for topical segmentation, due to their unstructured surface level, relative abundance (tens of thousands of such testimonies were collected), and the relatively confined domain that they cover. We hypothesize that boundary points between segments correspond to low mutual information between the sentences proceeding and following the boundary. Based on this hypothesis, we explore a range of algorithmic approaches to the task, building on previous work on segmentation that uses generative Bayesian modeling and state-of-the-art neural machinery. Compared to manually annotated references, we find that the developed approaches show considerable improvements over previous work.