CUET-NLP_Team_SS306 at AraGenEval Shared Task: A Transformer-based Framework for Detecting AI-Generated Arabic Text
Paper · 2025 · Sowrav Nath, Shadman Saleh, Kawsar Ahmed et al.
Summary
The paper addresses Task 3 of the AraGenEval 2025 shared task (ARATECT): deciding whether an Arabic text was written by a person or produced by an LLM such as GPT-4, Mistral or LLaMA. The CUET team fine-tunes several pretrained encoders: AraBERT, RoBERTa, Ara-RoBERTa, mBERT and MARBERT. Before training, the text is cleaned by stripping diacritics, unifying letter variants, and removing repeated characters and stray punctuation. Many documents are longer than the 512-token limit, so each one is cut into overlapping windows. Every window is classified on its own, and the window confidences are averaged per document to give the final label. On the official test set, AraBERT with this windowing reached F1 0.67 (up from 0.62), and the team placed 12th. On a held-out split of the training data the gains were larger. A breakdown by text length shows windowing helps most on long inputs, and Arabic-pretrained models behave more steadily than multilingual mBERT. The work is useful as a simple, reproducible baseline for machine-text detection in a morphologically rich, less-resourced language.
Key points
- The ARATECT data has 4,798 balanced training samples (2,399 human, 2,399 machine) and 500 unlabeled test samples. Human texts come from Arabic news sites and verified literary sources.
- Each text is split into chunks of 400 tokens with an overlap of 50 (max length 512), and document labels come from the mean chunk confidence. Training used batch 16, 5 epochs, learning rate 2e-5 and weight decay 0.001.
- On the official test set, AraBERT rose from 0.62 to 0.67 F1 and RoBERTa from 0.58 to 0.61.
- AraBERT's precision stayed near 0.5 while recall hit 0.97, so the model strongly leans toward the "machine" label.
- On the custom split, AraBERT went from 0.79 to 0.87 and MARBERT from 0.80 to 0.87. mBERT fell from 0.81 to 0.60, with the drop concentrated on short texts (−0.58). Ara-RoBERTa gained +0.66 on long texts.
- The chunked AraBERT got 431 of 500 texts right, but 69 human texts were still labeled as machine-generated.
Interesting ideas
- I1. Splitting a long input into overlapping windows, scoring each separately, and pooling the scores lets a fixed-context encoder use the whole document instead of only its opening.
- I2. Reporting scores separately for short, medium and long inputs exposed effects that the overall F1 hid, such as large gains concentrated on long texts.
- I3. The same trick helped some models and badly hurt another (mBERT on short texts), so each tweak needs a per-component ablation rather than a blanket adoption.
- I4. A detector with recall near 1 but precision near 0.5 is mostly defaulting to one class, which the confusion matrix makes visible.
- I5. Normalizing orthographic variants (diacritics, letter forms, repeated characters) before modeling reduces sparsity from surface noise.
For Mova
How these ideas could serve Mova, our small open language model — its files, stages and tests:
- I1 (tree): gparse could process over-long sentences or multi-sentence spans in overlapping windows and reconcile predictions for tokens in the overlap zone, avoiding silent truncation.
- I2 (learn): parser LAS and QA accuracy should be bucketed by sentence or story length so regressions on long inputs are not masked by easy short ones.
- I3 (learn): each new repair rule or training change should be ablated per parser and per witness before it is admitted into the silver-data pipeline.
- I4 (answer): readers' outputs on school tests could be checked for skew toward a default answer (e.g., always "yes" or the first option) using per-class confusion counts.
- I5 (tokens): crate en could normalize Unicode quotes, dashes, ligatures and elongated spellings ("sooo") into a canonical form, keeping the original for explainability.
Institutions
Fields, topics and concepts
📚 Shelves 4The field of science this work belongs to (OpenAlex fields).Computer Science · 18,614 worksArtificial Intelligence · 17,965 worksArts and Humanities · 17,450 worksLanguage and Linguistics · 17,296 works
🧭 Topics 1Research subjects and languages the work is about.Semitic languages · 3,066 works
Cite
Cite as Sowrav Nath, Shadman Saleh, Kawsar Ahmed and Mohammed Moshiul Hoque. 2025. CUET-NLP_Team_SS306 at AraGenEval Shared Task: A Transformer-based Framework for Detecting AI-Generated Arabic Text. Proceedings of The Third Arabic Natural Language Processing Conference: Shared Tasks.
@inproceedings{nath2025cuet,
title = {{CUET-NLP\_Team\_SS306 at AraGenEval Shared Task: A Transformer-based Framework for Detecting AI-Generated Arabic Text}},
author = {Sowrav Nath, Shadman Saleh, Kawsar Ahmed and Mohammed Moshiul Hoque},
booktitle = {Proceedings of The Third Arabic Natural Language Processing Conference: Shared Tasks},
year = {2025},
doi = {10.18653/v1/2025.arabicnlp-sharedtasks.11},
url = {https://doi.org/10.18653/v1/2025.arabicnlp-sharedtasks.11}
}References
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