The Problem of Identifying the Terrorists Bad Guys Quickly

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The Problem of Identifying the Terrorists (Bad
Guys) Quickly

• by
• Dr. Peter Chen
• Cyber Security Group
• Computer Science Dept
• LSU
• Baton Rouge, LA 70803

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Outline

• What is the Profiling Problem?
• Why is it so difficult?
• What are we doing about it?

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What is the Profiling Problem?
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In any population,
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there are bound to be bad guys
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there are bound to be bad guys
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Lets meet some of them
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A bad guy
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Another bad guy
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Several bad guys
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Looking more closely at each bad guy
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Bad guy 1

• black hair
• beard/moustache

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Bad guy 2

• well dressed
• beard/moustache

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Bad guy 3

• black hair
• beard/moustache

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Bad guy 4

• black hair
• highly strung
• skinny

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Attributes of bad guys

• black hair
• beard/moustache
• well dressed
• skinny

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black hair
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beard/moustache
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well-dressed
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highly strung
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skinny
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Using the fewest attributes to catch all the bad
guys

• black hair
• beard/moustache

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Unfortunately, in our population
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there are also good guys
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Looking more closely at each good guy
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Good guy 1

• beard/moustache

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Good guy 2

• beard/moustache
• well-dressed

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Good guy 3

• well-dressed

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Using the fewest attributes to catch all the bad
guys

• black hair
• beard/moustache

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also catches some good guys (casualties)

• black hair
• beard/moustache

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also catches some good guys (casualties)

• black hair
• beard/moustache

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Goal Find the smallest number of attributes
that will catch all the bad guys, but at the
same time Include as few casualties (good
guys) as possible.
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Some good guys are more important than others
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Some bad guys are more important (to capture)
than others
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Goal (more ambitious) Find the smallest number
of attributes that will catch as many, and
preferably the more important bad guys, but at
the same time Include as few, and preferably
the less important good guys, as possible.
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Why is the Profiling Problem so difficult?
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Why cant we just try all possible combinations
of attributes, and then pick the one that does
best?
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For, after all, computers are fast, arent they?
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This problem is complex

• Computers are fast, but not for certain problems,
  the complexity of the problems will make the
  computation time grow exponentially. The
  Profiling (Bad Guy Risk Assessment) is such a
  problem

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• Unfortunately, the Profiling Problem is one such
  problemAdding one more bad guy, or one more
  attribute may make the problem take twice as long
  to solve.
• Also, adding one more attribute value (for
  example, adding a new value on possible hair
  color will increase significantly the computation
  time.

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No use coming up with the best solution many
days/weeks/months after we are all dead and gone.
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OK. How about a quick method to find a solution
that close to the best?
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We have developed algorithms to solve this
problem that do not take so long, yet produce
very good results.
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Summary

• In the Profiling Problem, we want to catch as
  many bad guys, especially the real bad ones, and
  do so by disturbing as few good ones, especially
  the important ones.
• The Profiling Problem takes too long to solve if
  we want perfect solutions. No one knows if we can
  get perfect solutions fast.
• We have develop a quick algorithm to find the
  solutions in a reasonably short time.

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The End