A Novel Lecture Browsing System Using Ranked Key Phrases and StreamGraphs

  • A growing number of universities offer recordings of lectures, seminars and talks in an online e-learning portal. However, the user is often not interested in the entire recording, but is looking for parts covering a certain topic. Usually, the user has to either watch the whole video or “zap” through the lecture and risk missing important details. We present an integrated web-based platform to help users find relevant sections within recorded lecture videos by providing them with a ranked list of key phrases. For a user-defined subset of these, a StreamGraph visualizes when important key phrases occur and how prominent they are at the given time. To come up with the best key phrase rankings, we evaluate three different key phrase ranking methods using lectures of different topics by comparing automatic with human rankings, and show that human and automatic rankings yield similar scores using Normalized Discounted Cumulative Gain (NDCG).

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Author:Martin Gropp, Elmar Nöth, Korbinian Riedhammer
Parent Title (English):14th International Conference on Text, Speech and Dialogue (TSD), September 2011, Pilsen, Czech Republic.
Document Type:Conference Proceeding
Publication Year:2011
Tag:E-Learning; browsing; key phrases; ranking; visualization
First Page:17
Last Page:24
faculties / departments:Fakultät für Informatik
Dewey Decimal Classification:0 Informatik, Informationswissenschaft, allgemeine Werke / 00 Informatik, Wissen, Systeme / 000 Informatik, Informationswissenschaft, allgemeine Werke