6. The method of claim 1 , further comprising inducing labels for the two or more topic-specific portions based on the extracted key phrases present in the two or more topic segments.
7. The method of claim 6 , wherein the inducing further includes: receiving the topic segment borders, the extracted key phrases, and the assigned weights of each of the generated topic segments; based on topic window borders, segmenting the lecture video transcript into multiple sub-documents; reconstructing a refined vector representation for each of the multiple sub-documents; updating the assigned weights based on term frequency-inverse document frequency (TF-IDF) in each of the multiple sub-documents; selecting a candidate label based on the updated assigned weights for each of the multiple sub-documents; determining whether each of the candidate labels is one of the extracted key phrases; in response to the candidate label being one of the extracted key phrases, selecting the candidate label as a label for the sub-document; and in response to the candidate label not being one of the extracted key phrases, identifying the sub-document as off-topic.