Professor Nikos Aletras

About

I am a Professor of Natural Language Processing (NLP), currently leading the NLP Group at the School of Computer Science, University of Sheffield. Previously, I’ve gained industrial experience working as a Scholar and Applied Scientist at Amazon. Prior to Amazon, I was a research associate at UCL, Department of Computer Science, after I completed a PhD in Natural Language Processing at the University of Sheffield, Department of Computer Science.

Selected publications

• Cao M, Tan X, Akhter ME, Valentino M, Liakata M, Wang X & Aletras N (2026) Fundamental Reasoning Paradigms Induce Out-of-Domain Generalization in Language Models.. CoRR, abs/2602.08658.
• Yamaguchi A, Mi M & Aletras N (2026) Enhancing Linguistic Competence of Language Models through Pre-training with Language Learning Tasks.. CoRR, abs/2601.03448.
• Karouzos C, Tan X & Aletras N (2026) An Empirical Study on Preference Tuning Generalization and Diversity Under Domain Shift.. CoRR, abs/2601.05882.
• Yamaguchi A, Morishita T, Villavicencio A & Aletras N (2025) Mitigating Catastrophic Forgetting in Target Language Adaptation of LLMs via Source-Shielded Updates.. CoRR, abs/2512.04844.
• Yamaguchi A, Villavicencio A & Aletras N (2025) How can we effectively expand the vocabulary of LLMs with 0.01GB of target language text?. Computational Linguistics. View this article in WRRO
• Yamaguchi A, Morishita T, Villavicencio A & Aletras N (2025) Adapting chat language models using only target unlabeled language data. Transactions on Machine Learning Research, 2025(09). View this article in WRRO
• Alajrami A, Tan X & Aletras N (2025) Fine-Tuning on Noisy Instructions: Effects on Generalization and Performance.. CoRR, abs/2510.03528.
• Lewis-Lim S, Tan X, Zhao Z & Aletras N (2025) Can Confidence Estimates Decide When Chain-of-Thought Is Necessary for LLMs?. CoRR, abs/2510.21007.
• Cao M, Wang X & Aletras N (2025) Progressive Depth Up-scaling via Optimal Transport.. CoRR, abs/2508.08011.
• Fang J, Peng Y, Zhang X, Wang Y, Yi X, Zhang G, Xu Y, Wu B, Liu S, Li Z , Ren Z et al (2025) A Comprehensive Survey of Self-Evolving AI Agents: A New Paradigm Bridging Foundation Models and Lifelong Agentic Systems.. CoRR, abs/2508.07407.