Perturbation-based QE: An Explainable, Unsupervised Word-level Quality Estimation Method for Blackbox Machine Translation Tu Anh Dinh author Jan Niehues author 2023-09 text Proceedings of Machine Translation Summit XIX, Vol. 1: Research Track Masao Utiyama editor Rui Wang editor Asia-Pacific Association for Machine Translation Macau SAR, China conference publication dinh-niehues-2023-perturbation https://aclanthology.org/2023.mtsummit-research.6/ 2023-09 59 71