ISYS111 Lecture Notes - Lecture 19: Global Positioning System, Wireless, Wireless Lan
17 Jun 2018
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• Major legal issues of electronic commerce:
• Fraud:
o Online banks that disappear after taking customers' money
o Stock promoters who falsely spread rumours about stocks to increase
their value
o Auction fraud where either the sellers or the buyers don't get what they
thought they were getting from the other person
o Scams disseminated via e-mail
• Buyer protection and seller protection in electronic commerce:
• Buyer protection:
o Policy that some e-commerce sites have that protect the rights of the
buyer in a particular transaction to protect their interest
• Seller protection:
o Policies protecting the rights of the sellers
Wireless technology:
A. Wireless devices:
o Small enough to carry
o Sufficient computing power
o Communicate wirelessly with the internet and other devices
B. Most common types of wireless devices
o Pagers: one way wireless device
o PDA (personal digital assistant): small, handheld wireless device
o GPS (global positioning system): satellite-based tracking system enabling
users to determine the location of a GPS device or the location of a
specific address
o Smartphones: internet-enabled cell phone that can support mobile
applications (apps)
C. Advantages and disadvantages of wireless media:
Channel
Advantages
Disadvantages
Microwave
High bandwidth
Relatively
inexpensive
Must have unobstructed
line of sight
Susceptible to
environmental interferes
Satellite
High bandwidth
Large coverage area
Expensive
Must have unobstructed
line of sight
Signals experience
propagation delay
Must use encryption for
security
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