Oleh Melnychuk


2025

Detecting manipulation techniques in online text is vital for combating misinformation, a task complicated by generative AI. This paper compares machine learning approaches for multi-label classification of 10 techniques in Ukrainian Telegram content (UNLP 2025 Shared Task 1). Our evaluation included TF-IDF, fine-tuned XLM-RoBERTa-Large, PEFT-LLM (Gemma, Mistral) and a RAG approach (E5 + Mistral Nemo). The fine-tuned XLM-RoBERTa-Large model, which incorporates weighted loss to address class imbalance, yielded the highest Macro F1 score (0.4346). This result surpassed the performance of TF-IDF (Macro F1 0.32-0.36), the PEFT-LLM (0.28-0.33) and RAG (0.309). Synthetic data slightly helped TF-IDF but reduced transformer model performance. The results demonstrate the strong performance of standard transformers like XLM-R when appropriately configured for this classification task.
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