Panagiotis Kaliosis


2025

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LVLMs are Bad at Overhearing Human Referential Communication
Zhengxiang Wang | Weiling Li | Panagiotis Kaliosis | Owen Rambow | Susan Brennan
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing

During spontaneous conversations, speakers collaborate on novel referring expressions, which they can then re-use in subsequent conversations. Understanding such referring expressions is an important ability for an embodied agent, so that it can carry out tasks in the real world. This requires integrating and understanding language, vision, and conversational interaction. We study the capabilities of seven state-of-the-art Large Vision Language Models (LVLMs) as overhearers to a corpus of spontaneous conversations between pairs of human discourse participants engaged in a collaborative object-matching task. We find that such a task remains challenging for current LVLMs and they all fail to show a consistent performance improvement as they overhear more conversations from the same discourse participants repeating the same task for multiple rounds. We release our corpus and code for reproducibility and to facilitate future research.

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Learning to Align: Addressing Character Frequency Distribution Shifts in Handwritten Text Recognition
Panagiotis Kaliosis | John Pavlopoulos
Findings of the Association for Computational Linguistics: EMNLP 2025

Handwritten text recognition aims to convert visual input into machine-readable text, and it remains challenging due to the evolving and context-dependent nature of handwriting. Character sets change over time, and character frequency distributions shift across historical periods or regions, often causing models trained on broad, heterogeneous corpora to underperform on specific subsets. To tackle this, we propose a novel loss function that incorporates the Wasserstein distance between the character frequency distribution of the predicted text and a target distribution empirically derived from training data. By penalizing divergence from expected distributions, our approach enhances both accuracy and robustness under temporal and contextual intra-dataset shifts. Furthermore, we demonstrate that character distribution alignment can also improve existing models at inference time without requiring retraining by integrating it as a scoring function in a guided decoding scheme. Experimental results across multiple datasets and architectures confirm the effectiveness of our method in boosting generalization and performance. We open source our code at https://github.com/pkaliosis/fada.

2024

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A Data-Driven Guided Decoding Mechanism for Diagnostic Captioning
Panagiotis Kaliosis | John Pavlopoulos | Foivos Charalampakos | Georgios Moschovis | Ion Androutsopoulos
Findings of the Association for Computational Linguistics: ACL 2024