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3 main measurements of the digital world
- 1) processing power
- 2) Storage (bytes)
- 3) Bandwidth (bits per second)
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Moore's Law
a prediction by Gordon E. Moore that the number of transistors that can be built into a given amount if chip space will double every 2 years.
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Bandwidth
The transmission capacity of a telecommunications pathway, electronic, or optical. Range of frequencies, expressed in Hertz (Hz). The difference between the lowest and highest frequencies carried on the channel. Determines the rate information is transmitted through a circuit. The greater the Bandwidth, the more data that can be carried.
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Voice communication
A narrow band. Do not require large amount of network caacity.
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Data Communications
the exchange of digitized text or document information between 2 machines. Medium to high bandwidth is needed.
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Image communication
requires medium to high bandwidth. The greater the resolution, the greater the bandwidth.
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Video Communication
requires the greatest amount of bandwidth. Need to learn to eliminate the delay.
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SMART Tags
example- RFID
Identifies objects or people at far distances.
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SMART devices
appliances, furniture, clothes, equipment, etc that incorporate technology in order to improve everyday life.
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Smart Office
Roomware that ensures freater efficiency and better working conditions in the workplace.
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Intelligent Agents
Draw its own conclusions and make decisions independently.
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User Agents
Can execute orders, conduct negotiations, and communicate independently with other agents. Acts as a substitute for the agent.
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Cooperative Agents
Perform liaison function, analyzing and interpreting the user's tasks and then deciding which functional agent would be appropriate.
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Functional Agent
Contain specific knowledge required to carry out a particular function.
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Circuit
the physical path that runs between 2 or more points. It ends at a port (oint of electrical interface) which is attached to a computer or switch.
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Channel
The frequency band, time slot, or wavelength allocate to a singer conversation.
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Virtual Circuit
a series of logical connections between sending and receiving data. It is the connection between devices that acts as though it's a direct connection, but it may in fact be composed of a variety of different routes.
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Frequency
The number of oscillations per second of a electro magnetic wave.
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Wavelength
The distance between 2 consecutive maxima or minima of the waveform.
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Amplitude
The measure of the height of the wave.
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Codec
Converts analog signals into digital signals.
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Modem
is used to infuse digital data onto transmission facilities and vice versa.
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Multiplexers
reduce network costs by minimizing the number of communications links needed between 2 points.
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FSS- Fixed Satellite
conventional fixed services. C-Band and Ku-band.
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Broadcast Satellite Services (BSS)
television and direct broadcast. Ku-band @ 18GHz.
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Mobile Satellite Service (MSS)
accomodate mobile users.
Use Ka-band or L-band.
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Satellite Footprint
the area of the earth that the satellite's beam covers.
If satellite information is not in a footprint, it needs to use a relay satellite.
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C-band
uplink around 6GHz
downlink 4GHz
Since it operates in a low frequency, it handles well in weather.
Downside- shared by terrestrial systems.
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Ku-Band
uplink 14GHz
downlink 11GHz.
NO conflict with terrestrial systems. (used on top of news van)
Higher frequency- distorts in weather.
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Ka-band
wide frequency band.
Uplink 30GHz
downlink 20 GHz
Better for tele-medicine, education, surveillance, etc.
Faces issues in weather.
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L-Band
390 MHz to 1,550 MHz
Lower frequency and are more tollerent of bad weather. GPS and PDAs
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3 major orbits-
LEO
MEO
EARTH GEO
GEO- geosynchronous orbit.
MEO- middle earth orbit
LEO- low earth orbit
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Satellite vs. Microwave
Satellite is point to point from above the earth
Microwave is point to point on the earth.
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TCP/ IP
transmission control protocol/internet protocol: a set of protocols (including TCP) developed for the internet in the 1970s to get data from one ...
- a 4 layer network
- 4- Applications (email/peer-to-peer)
- 3- TCP/UDP/SCTP/DCCP (host-to-host transport)
- 2- IP
- 1- Network interface (ethernet)
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Data Communication
the exchange of digital information between computers and other digital devices via telecommunications nodes and wired or wireless links.
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LAN (Local Area Connection)
A system for linking terminals, programs, storage, and graphic devices at multiple work stations over relatively small geographic areas. i.e.- office
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WAN (wide area conneciton)
a group of computer networks connected over long distances, often by telephone or satellite transmission.
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internet
a collection of packet-switching networks interconnected by routers along with protocols that allow them to function logically as a single, large, virtual network.
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Intranet
A network based on TCP/IP protocols. It belongs to an organization and only those members can access it.
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Extranet
A network between partnering organizations.
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