Jan Pfister


2023

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Pointer Networks: A Unified Approach to Extracting German Opinions
Julia Wunderle | Jan Pfister | Andreas Hotho
Proceedings of the 19th Conference on Natural Language Processing (KONVENS 2023)

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Jack-Ryder at SemEval-2023 Task 5: Zero-Shot Clickbait Spoiling by Rephrasing Titles as Questions
Dirk Wangsadirdja | Jan Pfister | Konstantin Kobs | Andreas Hotho
Proceedings of the 17th International Workshop on Semantic Evaluation (SemEval-2023)

In this paper, we describe our approach to the clickbait spoiling task of SemEval 2023.The core idea behind our system is to leverage pre-trained models capable of Question Answering (QA) to extract the spoiler from article texts based on the clickbait title without any task-specific training. Since oftentimes, these titles are not phrased as questions, we automatically rephrase the clickbait titles as questions in order to better suit the pretraining task of the QA-capable models. Also, to fit as much relevant context into the model’s limited input size as possible, we propose to reorder the sentences by their relevance using a semantic similarity model. Finally, we evaluate QA as well as text generation models (via prompting) to extract the spoiler from the text. Based on the validation data, our final model selects each of these components depending on the spoiler type and achieves satisfactory zero-shot results. The ideas described in this paper can easily be applied in fine-tuning settings.

2022

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SenPoi at SemEval-2022 Task 10: Point me to your Opinion, SenPoi
Jan Pfister | Sebastian Wankerl | Andreas Hotho
Proceedings of the 16th International Workshop on Semantic Evaluation (SemEval-2022)

Structured Sentiment Analysis is the task of extracting sentiment tuples in a graph structure commonly from review texts. We adapt the Aspect-Based Sentiment Analysis pointer network BARTABSA to model this tuple extraction as a sequence prediction task and extend their output grammar to account for the increased complexity of Structured Sentiment Analysis. To predict structured sentiment tuples in languages other than English we swap BART for a multilingual mT5 and introduce a novel Output Length Regularization to mitigate overfitting to common target sequence lengths, thereby improving the performance of the model by up to 70%. We evaluate our approach on seven datasets in five languages including a zero shot crosslingual setting.