distance education systems agenda. distance education systems asynchronous communication: delayed...
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Distance Education Systems
Asynchronous Communication:• Delayed ________ between
teacher and student.
Synchronous Communication• Real-time ________ between
teacher and student
Asynchronous Technologies “____________ ______"
• Print-based• Audio-based
–radio–audiotape
• Video-based–broadcast television –videotape
Print-based Correspondence
Normally, learning materials (textbook, study guide) are delivered by _____.
Original form of distance education -- dates from mid-_____s.
Advantages–Learner-paced–Can be used anywhere–___ _____
Disadvantages–Limited __________–Motion cannot be shown–Tarnished _________
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
"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
Audio and Video-based Correspondence Study
Learning materials include __________________________________.
• Advantages: similar to print-based.with visual and/or audio component
• Disadvantage: limited interactivity
Interactive Telecommunications
• Audioconferencing• ________• _________ (ITFS)• Compressed ____• Fiber-optics
Audioconferencing
Teacher and students linked by telephone --a “__________ ____."
• Advantages: relatively inexpensive, flexible
• Disadvantage: lacks visual component
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)
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
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
Advantages
• ____ ______ video• Control over who receives signal• Excellent audio and video quality• No ___________ required
Jones. et al., 1992
Disadvantages
• Transmissions affected by _______• _________ only• Limited number of __________ available
Jones. et al., 1992
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
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
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