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Info and comm : terminology

Info and comm : terminology. tkkwon@snu.ac.kr. Outline. Data vs. Information Data vs. signal Communications Networks Service Protocol Convergence. Data raw facts no context just numbers and text. Information data with context processed data value-added to data summarized

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Info and comm : terminology

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  1. Info and comm: terminology tkkwon@snu.ac.kr

  2. Outline • Data vs. Information • Data vs. signal • Communications • Networks • Service • Protocol • Convergence

  3. Data raw facts no context just numbers and text Information data with context processed data value-added to data summarized organized analyzed Data vs. Information 0

  4. Data vs. Information • Data: 51007 • Information: • 5/10/07 May 10th in 2007. • $51,007 The average starting salary of an accounting major. • 51007 Zip code of Bronson, Iowa.

  5. Data vs. Information Information Data • 6.34 • 6.45 • 6.39 • 6.62 • 6.57 • 6.64 • 6.71 • 6.82 • 7.12 • 7.06

  6. Data  Information  Knowledge Data Summarizing the data Averaging the data Selecting part of the data Graphing the data Adding context Adding value Information

  7. Data  Information  Knowledge Information How is the info tied to outcomes? Are there any patterns in the info? What info is relevant to the problem? How does this info effect the system? What is the best way to use the info? How can we add more value to the info? Knowledge

  8. From now on “Data” and “information” are interchangeable But “data” will be often preferred Let’s focus on “data” vs. “signal”

  9. Analog data vs. digital data • Analog data – data has continuous values, • e.g. sound, image,… • Depending on storage format: LP, VHS magnetic tape • Natural phenomenon • Digital data – data has discrete values • e.g. text, integers,… • Depending on storage/device: DVD, digital camera • Most computing devices

  10. Analog-to-Digital Converter (ADC) • Due to information technologies • VLSI, DSP, digital communications, …

  11. Digital data • Bit • Nibble • Byte (octet) • Any binary stream … Now almost every kind of data is converted to digital….

  12. Image as digital data • an artifact, usually two-dimensional, that has a similar appearance to some subject • a pixel (picture element) is the smallest piece of information in an image • A pixel is one bit long in black and white • A pixel requires much longer bits in color systems • E.g. red, green, and blue

  13. Other digital data • text • Voice? • Audio/sound? • Video? • Binary code

  14. Datavs. signal • Digital data vs. analog data • Digital signal vs. analog signal • Data are symbols like numbers that carry info. while a signal refers to physical representation of data, electrically or electromagnetically

  15. signal • A signal is a time-varying value (electric or electromagnetic representation) or event that conveys information from a transmitter to a receiver

  16. analog signal • Analog signal changes over time and takes an infinite number of values

  17. Digital signal • Digital signal changes over time and takes a limited number of values

  18. Analog signal • A continuous function of time and location • An analog signal can be represented by a sum of periodic signals within a relatively small range • Why?

  19. Signal 101 • function of time and location • parameters of periodic signals: period T, frequency f=1/T, amplitude A, phase shift  • E.g., sinewave is expressed as s(t) = Atsin(2  ftt + t) • Any signal can be represented by a sum of periodic signals : phi [fee]

  20. signal • Different representations of signals • Amplitude over time (time domain) • frequency spectrum (frequency domain) • phase state diagram (amplitude M and phase  in polar coordinates) Q = M sin  A [V] A [V] t[s]  I= M cos   f [Hz]

  21. Analog signal is the winner • Analog signal occupies less frequency spectrum • High frequency component suffers from high attenuation • In data domain, digital is the winner

  22. That’s why there are so many modems • Modem: modulator and demodulator • DSL modem, CATV modem, LTE modem, WiFi modem…

  23. Advantages of Digital (data) Transmission • Digital technology • Low cost LSI/VLSI technology • Data integrity • Longer distances over lower quality lines • Capacity utilization • High bandwidth links economical • High degree of multiplexing easier with digital techniques • Security & Privacy • Encryption

  24. communications • a process of transferring information from one entity to another via a medium/channel • Transmission and reception • Data – signal - data

  25. (computer) networks • a group of interconnected computing devices • Medium • Wire vs. wireless • Scale • BAN, PAN, LAN, MAN, WAN • Relationship • Client-server, peer-to-peer • Topology • Tree, bus, star,… • Network operator * Why switches/routers? * source, sink, origin, destination, sender, transmitter, receiver

  26. protocol • A protocol is a set of rules which is used by computers to communicate with each other across a network • A protocol is a convention or standard that controls or enables the connection and data transfer between computing endpoints

  27. service • the provision of functions within a systems environment • a mechanism to enable access to one or more capabilities, where the access is provided using a prescribed interface and is exercised with constraints and policies as specified by the service description • a network service is an application running at the network application layer and above, that provides functionalities like storage, manipulation, presentation, communication • A service provider is an entity that provides services to other entities. • ISP, NO, CP, …

  28. Players in Mobile Networks • Customer • Mobile network operator (MNO) • Also called wireless internet service provider (ISP) • Mobile virtual network operator (MVNO) • Content provider (CP) • In-house vs. third party • Equipment vendor • Also called Manufacturer • CATV: System operator (SO), network operator (NO), program provider (PP), MSO (multiple SO) • Internet: ISP, NO, MVNO, CP

  29. convergence • Convergence (telecommunications): the combination of multiple services through lines of telecommunication from a single provider • Triple play service • Quadruple play service • Technological convergence: a trend where some technologies having distinct functionalities evolve to technologies that overlap • E. g. Mobile phones are another good example, in that they increasingly incorporate digital cameras, mp3 players, camcorders, voice recorders, and other devices. • More heterogeneous case?

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