This paper describes our contribution to SemEval-23 Shared Task 12: ArfiSenti. The task consists of several sentiment classification subtasks for rarely studied African languages to predict positive, negative, or neutral classes of a given Twitter dataset. In our system we utilized three different models; FastText, MultiLang Transformers, and Language-Specific Transformers to find the best working model for the classification challenge. We experimented with mentioned models and mostly reached the best prediction scores using the Language Specific Transformers. Our best-submitted result was ranked 3rd among submissions for the Amharic language, obtaining an F1 score of 0.702 behind the second-ranked system.

This paper describes our contribution to SemEval-2021 Task 5: Toxic Spans Detection. Our approach considers toxic spans detection as a segmentation problem. The system, Waw-unet, consists of a 1-D convolutional neural network adopted from U-Net architecture commonly applied for semantic segmentation. We customize existing architecture by adding a special network block considering for text segmentation, as an essential component of the model. We compared the model with two transformers-based systems RoBERTa and XLM-RoBERTa to see its performance against pre-trained language models. We obtained 0.6251 f1 score with Waw-unet while 0.6390 and 0.6601 with the compared models respectively.