stem/AI/Classification
andy b24f551589 vault backup: 2023-06-12 19:07:33
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STEM/AI/Classification/Gradient Boosting Machine.md
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STEM/AI/Pattern Matching/Dynamic Time Warping.md
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Supervised vault backup: 2023-06-08 17:52:08 2023-06-08 17:52:09 +01:00
Classification.md vault backup: 2023-06-07 09:02:27 2023-06-07 09:02:27 +01:00
Decision Trees.md vault backup: 2023-06-07 09:02:27 2023-06-07 09:02:27 +01:00
Gradient Boosting Machine.md vault backup: 2023-06-12 19:07:33 2023-06-12 19:07:33 +01:00
Logistic Regression.md vault backup: 2023-06-07 09:02:27 2023-06-07 09:02:27 +01:00
Random Forest.md vault backup: 2023-06-07 09:02:27 2023-06-07 09:02:27 +01:00
README.md vault backup: 2023-06-02 17:17:29 2023-06-02 17:17:29 +01:00

Given an observation, determine one class from a set of classes that best explains the observation

Features are discrete or continuous

  • 2 category classifier
    • Dichotomiser

Argmax

Argument that gives the maximum value from a target function

Gaussian Classifier

Training

  • Each class $i$ has it's own Gaussian N_i=N(m_i,v_i)
\hat i=\text{argmax}_i\left(p(o_t|N_i)\cdot P(N_i)\right)
\hat i=\text{argmax}_i\left(p(o_t|N_i)\right)
  • With equal priors

Discrete Classifier

  • Each class i has it's own histogram H_i
    • Describes the probability of each observation type k
    • P(o_t=k|H_i), based on class-specific type counts
\hat i=\text{argmax}_i\left(P(o_t=k|H_i)\right)
  • Nothing else known about classes
\hat i=\text{argmax}_i\left(P(o_t=k|H_i)\cdot P(H_i)\right)
  • Given class priors P(H_i)
  • Maximum posterior probability
    • Bayes