Computers in Society

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Computers in Society

• Representation

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Quiz Time

• Since I can't remember to do this at the end of
  class!

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Homework 4

• It's in the wiki.
• You need to do some research and find an
  interesting story about encryption.
• Someone who should have and didn't
• Someone who used poor encryption
• Someone who tangled with the courts over
  encryption
• Government attempts to control encryption
• Someone who cracked an encryption scheme

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Your Writeup

• I need a wiki page (outline of the story,
  references)
• I need a poster (nice graphic design)
• Do a good job of looking for a story!
• Have a wiki page and a pointer to a primary
  reference by Thursday.

5
Teamwork Issues

• Working in groups is IMPORTANT
• Working in groups is HARD
• If you don't put in the effort you should your
  group will talk to me. I'm the next level of
  management I don't want to hear about your
  group if everything is going OK. But if things
  go bad I have the power to fire you (kick you out
  of a group) or punish you (give you a lower grade
  than your group)

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Presentations

• Your oral presentations are REALLY IMPORTANT!
• I want to see
• Good visual aids
• Research beyond the primary article
• Cooperation among group members
• Division of responsibilities
• Interaction with the audience (ask questions,
  take a poll, solicit opinions)

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Information
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Representation

• The fundamental idea in computing is
  representation turning objects into binary
  numbers.
• We can do this with MANY sorts of things
• Numbers
• Sound
• Pictures
• Movies
• CAD drawings

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What's the BIG DEAL?

• By converting into a binary representation, we
  can use the same technology to store and transmit
  ALL kinds of objects.
• If you can copy a file, you can copy a downloaded
  song.
• A network that lets you buy plane tickets also
  lets you swap pirated movies
• The same disk holds ALL information, not just one
  type.

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Representation

• How can we tell exactly what a bunch of 0's and
  1's represent?
• We can't! Every bit of computer information must
  be associated with an interpretation to be
  meaningful.
• The interpretation gives semantics to the 0's and
  1's.

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Specific Representations

• Give some examples of representations we know.

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Interpretations

• What are ways that we provide interpretations for
  digital information?

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Operating on 1's and 0's

• What can we do with uninterpreted information?

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Playing with 0's and 1's

• Storage and retrieval
• Transmission
• Encryption
• Compression