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This is an old revision of this page, as edited by Flow~enwiki (talk | contribs) at 21:12, 22 November 2004 (Notes in preparation for the SYDE 372 Final Exam, Winter 2004). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.


Linear Discriminants

What they are: straight line classifiers

Advantages

  • fastest, simplest possible classifier

Disadvantages

  • simplistic, and high probability of error, however, this can be overcome/mitigated by
1) transforming the data by some high-dimensional non-linear functions, 
and  creating the straight line in non-linear space (Support Vector Machines)
OR
2) Combining several discriminants when making a classifier by
   i) voting
   ii) aggregation
   iii) Neural Networks (uses some kind of voting?)


Perceptron algorithm

What it does: finds a linear discriminant between two clusters

Advantages

  • will always find a discriminant, if one exists

Disadvantages

  • discriminant usually not optimum, or close to optimum
  • premature halting of the algorithm gives nonsense
  • may require an arbitrary number of iterations - number of iterations is inversely proportional to distance between clusters


Minimum Square Error (MSE)

What it does: finds a linear discriminant between clusters, by the least squares solution of the distance from (all points in the cluster or only the closest?) to the line

Advantages

  • will always give a 'reasonable' result, even if the clusters are not separable

Disadvantages

Template Title

What it does:

Advantages

Disadvantages


Some examples of mathematical expressions:

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Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "http://localhost:6011/en.wikipedia.org/v1/":): {\displaystyle T_P = \frac{\pi} {\omega_n \sqrt{1-\zeta^2}} }