Wencke Liermann


2024

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More Insightful Feedback for Tutoring: Enhancing Generation Mechanisms and Automatic Evaluation
Wencke Liermann | Jin-Xia Huang | Yohan Lee | Kong Joo Lee
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing

Incorrect student answers can become valuable learning opportunities, provided that the student understands where they went wrong and why. To this end, rather than being given the correct answer, students should receive elaborated feedback on how to correct a mistake on their own. Highlighting the complex demands that the generation of such feedback places on a model’s input utilization abilities, we propose two extensions to the training pipeline. Firstly, we employ a KL regularization term between a standard and enriched input format to achieve more targeted input representations. Secondly, we add a preference optimization step to encourage student answer-adaptive feedback generation. The effectiveness of those extensions is underlined by a significant increase in model performance of 3.3 METEOR points. We go beyond traditional surface form-based metrics to assess two important dimensions of feedback quality, i.e., faithfulness and informativeness. Hereby, we are the first to propose an automatic metric measuring the degree to which feedback divulges the correct answer, that we call Informativeness Index I2. We verify in how far each metric captures feedback quality.

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Improving Backchannel Prediction Leveraging Sequential and Attentive Context Awareness
Yo-Han Park | Wencke Liermann | Yong-Seok Choi | Kong Joo Lee
Findings of the Association for Computational Linguistics: EACL 2024

Backchannels, which refer to short and often affirmative or empathetic responses from a listener during a conversation, play a crucial role in effective communication. In this paper, we introduce CABP(Context-Aware Backchannel Prediction), a sequential and attentive context approach aimed at enhancing backchannel prediction performance. Additionally, CABP leverages the pretrained wav2vec model for encoding audio signal. Experimental results show that CABP performs better than context-free models, with performance improvements of 1.3% and 1.8% in Korean and English datasets, respectively. Furthermore, when utilizing the pretrained wav2vec model, CABP consistently demonstrates the best performance, achieving performance improvements of 4.4% and 3.1% in Korean and English datasets.

2023

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Dialogue Act-Aided Backchannel Prediction Using Multi-Task Learning
Wencke Liermann | Yo-Han Park | Yong-Seok Choi | Kong Lee
Findings of the Association for Computational Linguistics: EMNLP 2023

Produced in the form of small injections such as “Yeah!” or “Uh-Huh” by listeners in a conversation, supportive verbal feedback (i.e., backchanneling) is essential for natural dialogue. Highlighting its tight relation to speaker intent and utterance type, we propose a multi-task learning approach that learns textual representations for the task of backchannel prediction in tandem with dialogue act classification. We demonstrate the effectiveness of our approach by improving the prediction of specific backchannels like “Yeah” or “Really?” by up to 2.0% in F1. Additionally, whereas previous models relied on well-established methods to extract audio features, we further pre-train the audio encoder in a self-supervised fashion using voice activity projection. This leads to additional gains of 1.4% in weighted F1.

2022

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The slurk Interaction Server Framework: Better Data for Better Dialog Models
Jana Götze | Maike Paetzel-Prüsmann | Wencke Liermann | Tim Diekmann | David Schlangen
Proceedings of the Thirteenth Language Resources and Evaluation Conference

This paper presents the slurk software, a lightweight interaction server for setting up dialog data collections and running experiments. slurk enables a multitude of settings including text-based, speech and video interaction between two or more humans or humans and bots, and a multimodal display area for presenting shared or private interactive context. The software is implemented in Python with an HTML and JavaScript frontend that can easily be adapted to individual needs. It also provides a setup for pairing participants on common crowdworking platforms such as Amazon Mechanical Turk and some example bot scripts for common interaction scenarios.