This document summarizes a research paper on developing a fast and scalable semi-supervised method for video action recognition using conditional random fields. The proposed method, called semi-supervised virtual evidence boosting (sVEB), simultaneously performs feature selection and semi-supervised training of CRFs using both labeled and unlabeled data. sVEB reduces the amount of labeling required during training while maintaining high accuracy, making it suitable for real-world applications. Experimental results on synthetic and activity recognition tasks demonstrate that sVEB outperforms other training techniques in terms of accuracy while being more computationally efficient.