1 / 23

Distance Education Systems

Distance Education Systems. Agenda. Distance Education Systems. Asynchronous Communication: Delayed interaction between teacher and student. Synchronous Communication Real-time interaction between teacher and student. Asynchronous Technologies "Correspondence Study". Print-based

patriciag
Download Presentation

Distance Education Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Distance Education Systems Agenda

  2. Distance Education Systems Asynchronous Communication: • Delayed interaction between teacher and student. Synchronous Communication • Real-time interaction between teacher and student

  3. Asynchronous Technologies "Correspondence Study" • Print-based • Audio-based • radio • audiotape • Video-based • broadcast television • videotape

  4. Print-based Correspondence Normally, learning materials (textbook, study guide) are delivered by mail. Original form of distance education -- dates from mid-1800s.

  5. Advantages • Learner-paced • Can be used anywhere • Low cost Disadvantages • Limited interactivity • Motion cannot be shown • Tarnished reputation

  6. I opened a letter and read it. it offered me a six months' correspondence course in finger printing at a special professional discount. I dropped it into the wastebasket..." The Big Sleep. by Raymond Chandler

  7. "Allied Commissioners' Courses; be a detective, send for a one-volume correspondence course. No tests, no instructors, no salesmen will call. Free handcuffs and badge included as a special bonus if you act now." Good Behavior. by Donald Westlake

  8. Audio and Video-based Correspondence Study • Learning materials include textbook and workbook, plus audio-or videotape • Advantages: similar to print-based.with visual and/or audio component • Disadvantage: limited interactivity

  9. Interactive Telecommunications • Audioconferencing • Satellite • Microwave (ITFS) • Compressed video • Fiber-optics

  10. Audioconferencing Teacher and students linked by telephone --a "conference call." • Advantages: relatively inexpensive, flexible • Disadvantage: lacks visual component

  11. Satellite-based Distance Education • "Uplink" transmits signal to satellite in geosynchronous orbit. Transponder amplifies signal, transmits it back to earth. Signal is received by "downlinks" (satellite dishes):

  12. Satellite

  13. Advantages • Huge "footprint" means programming can be delivered virtually anywhere to virtually unlimited number of sites Disadvantages • Very expensive to purchase and operate • Normally, video is only one way and students use telephone to communicate with teacher

  14. Microwave-based (ITES) Distance Education • Essentially, low powered TV • Special frequencies/channels • Point-to-point or multipoint • Line-of-sight, 25-30 miles max. • Usually one-way video, two-way audio

  15. Advantages • Full motion video • Control over who receives signal • Excellent audio and video quality • No right-of-ways required Jones. et al., 1992

  16. Microwave

  17. Disadvantages • Transmissions affected by weather • Line-of-site only • Limited number of frequencies available Jones. et al., 1992

  18. Compressed Video-based Distance Education • Analog video signal digitized, then: • Processed to reduce unnecessary information transmitted • Copper telephone lines connect sites • Not full-motion--fewer than 30 images per second

  19. Advantages • Easy to install and use • Can be cheaper than fiber or microwave Disadvantages: • Motion can be jerky • Video quality can be poor • Can't transmit full-motion video Jones. et al., 1992

  20. Compressed Video

  21. Fiber Optics-based Distance Education • Used for telephone and cable TV main trunk lines • Only recently used for education • Cable uses optically pure glass • Transmits light energy

  22. Fiber Optics

  23. Advantages • Full-motion video • High quality • Unaffected by weather Disadvantages • High start-up costs • Slow, expensive repairs • Right-of-way costs Jones. et al., 1992

More Related