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Challenge the future
DelftUniversity ofTechnology
Navigation and searchingin recorded lectures
2Navigation and searching in recorded lectures
Personal details authors
Peter de MoelLecturer Drinking water Engineering /Project manager Pilot Delft
OpenCourseWareDelft University of Technology
(Netherlands)
Erwin de MoelMSc graduate Computer ScienceUniversity of Twente (Netherlands)
Jasper VerberkAssociate professor Drinking Water
EngineeringDelft University of Technology
(Netherlands)
Djoerd HiemstraAssociate professor Database TechnologyUniversity of Twente (Netherlands)
3Navigation and searching in recorded lectures
Expanding the use of recorded lectures
Backgrounds:• TU Delft OpenCourseWare • Recorded lectures at Delft and Twente (identical recording
systems)• Speech recognition for video searching in Twente
MSc project in Computer Science
http://www.citg.tudelft.nl/live/pagina.jsp?id=69192d7e-3eaf-4788-b936-21808aa8de29&lang=en
4Navigation and searching in recorded lectures
Recorded lectures
Course size 1 lecture 30-40 lecturesRecording duration 15 minutes 100-120 minutesVideo resolution 340x240 (iPOD)
1920x1280 (HD)File location Streaming DownloadMovie content All-in-one video
Video + screenshots
Large variation
5Navigation and searching in recorded lectures
Content
• What is in this course ? Lectures / Subject per lecture• What is in this lecture ? Subjects• How do I navigate ? Time slider or Table Of Content• Where starts the subject…..?• Where is something on ……..?
Main questions for students
6Navigation and searching in recorded lectures
Content of a course / lectures
• Overview of lectures• Text / pictures / pictures+text
Table of Content
7Navigation and searching in recorded lectures
Content of a lecture
• Chapters and Paragraphs• Link to start time• Combined in ELS
Table of Content
8Navigation and searching in recorded lectures
Content of a lectureInteractive Table of Content
9Navigation and searching in recorded lectures
Content of a lecture
• Best sources: subtitles and speech recognition (over slides)
Tag clouds
10Navigation and searching in recorded lectures
Content of a lecture
• Improvement by lecturer
Tag clouds
11Navigation and searching in recorded lectures
SubtitelsAnd translated subtitles (online in YouTube)
http://www.youtube.com/watch?v=9na2hHJmmvE
12Navigation and searching in recorded lectures
Subtitels
Mean word correctness 50% (range 25 – 75%)
Creation with speech recognition
13Navigation and searching in recorded lectures
Meta data of lecturesCourse with 28 lectures (45 minutes)
14Navigation and searching in recorded lectures
Collegerama lecture search
• Lecture titles • Slide titles
Table of content
15Navigation and searching in recorded lectures
Collegerama lecture search
• Human made subtitles better than speech recognition• Slide content is not a good source for search engines• Multiple keyword result per slide: much shorter viewing
time
Search engine
16Navigation and searching in recorded lectures
Presentation in ELSTOC – downloads – search engine
Challenge the future
DelftUniversity ofTechnology
http://ocw.tudelft.nlhttp://drinkwater.tudelft.nlcontact: [email protected]
