Distance Education Systems

1
Distance Education Systems

• Agenda

2
Distance Education Systems

• Asynchronous Communication
• Delayed ________ between teacher and student.
• Synchronous Communication
• Real-time ________ between teacher and student

3
Asynchronous Technologies ____________ ______"

• Print-based
• Audio-based
• radio
• audiotape
• Video-based
• broadcast television
• videotape

4
Print-based Correspondence

• Normally, learning materials (textbook, study
  guide) are delivered by _____.
• Original form of distance education -- dates
  from mid-_____s.

5

• Advantages
• Learner-paced
• Can be used anywhere
• ___ _____
• Disadvantages
• Limited __________
• Motion cannot be shown
• Tarnished _________

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 ______________________
  ____________.
• Advantages similar to print-based.with visual
  and/or audio component
• Disadvantage limited interactivity

9
Interactive Telecommunications

• Audioconferencing
• ________
• _________ (ITFS)
• Compressed ____
• Fiber-optics

10
Audioconferencing

• Teacher and students linked by telephone --a
  __________ ____."
• Advantages relatively inexpensive, flexible
• Disadvantage lacks visual component

11
Satellite-based Distance Education

• _______" transmits signal to satellite in
  geosynchronous orbit. T_________ amplifies
  signal, transmits it back to earth. Signal is
  received by _______" (satellite dishes)

12
Satellite
13

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

14
Microwave-based (ITFS) Distance Education

• Essentially, low powered ___
• Special frequencies/channels
• Point-to-point or _________
• Line-of-sight, 25-30 miles max.
• Usually one-way video, two-way audio

15
Advantages

• ____ ______ video
• Control over who receives signal
• Excellent audio and video quality
• No ___________ required

Jones. et al., 1992
16
Microwave
17
Disadvantages

• Transmissions affected by _______
• _________ only
• Limited number of __________ available

Jones. et al., 1992
18
Compressed Video-based Distance Education

• _____ _____ signal digitized, then
• Processed to reduce unnecessary information
  transmitted
• _______ telephone lines connect sites
• Not full-motion--fewer than ___ images per second

19

• Advantages
• Easy to install and use
• Can be c_______ than fiber or microwave
• Disadvantages
• Motion can be _____
• Video quality can be poor
• Can't transmit ___-_____ video

Jones. et al., 1992
20
Compressed Video
21
Fiber Optics-based Distance Education

• Used for telephone and cable TV main t____ lines
• Only recently used for education
• Cable uses optically pure _____
• Transmits _____ energy

22
Fiber Optics
23

• Advantages
• Full-______ _____
• High quality
• Unaffected by _______
• Disadvantages
• ____ start-up costs
• Slow, expensive repairs
• _____-__-____ costs

Jones. et al., 1992