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Anomaly Detection Module

David Ray edited this page Feb 21, 2015 · 20 revisions

Anomaly Detection / Anomaly Likelihood Functionality Added!

As part of the Network API development effort, it was decided that the production of a Java™ version of the Python NuPIC Network API Demo(s) (PNA) would be one of its downstream validating deliverables. One of the PNA Demo's dependencies was the as of yet uncompleted Anomaly/AnomalyLikelihood computation classes. As such, a giant segue (read sidetrack :-P) was born!

So as a result we now have a major piece of functionality added to the "Algorithms" package which contains the classes organized around CLA Classification.

Usage

There are 3 explicit modes in which anomaly functionality can be used:

  1. Static call to obtain anomaly score.
    Ex.

    int[] currentlyActiveColumns = { 3, 5, 7 };    // Array containing col indexes    
    int[] predictedActiveColumns = { 2, 5, 6 };       
    double score = Anomaly.computeRawAnomalyScore(currentlyActiveColumns, predictedActiveColumns);     
    
  1. Factory instantiation of Anomaly instance.
    Ex.

    Map<String, Object> params = new HashMap<>();    
    params.put(KEY_MODE, Mode.PURE);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// May be Mode.LIKELIHOOD    
    params.put(KEY_USE_MOVING_AVG, true);&nbsp;&nbsp;&nbsp;&nbsp;// Instructs the Anomaly class to compute moving  average    
    params.put(KEY_WINDOW_SIZE, 10);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// #of inputs over which to compute the moving average    
    params.put(KEY_IS_WEIGHTED, true);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// Use a weighted moving average or not     
    
    Anomaly anomalyComputer = Anomaly.create(params);    
    double score = anomalyComputer.compute(currentlyActiveColumns, predictedActiveColumns, 0, 0);     
    
  1. Likelihood Prediction
    Ex.

    Map<String, Object> params = new HashMap<>();    
    params.put(KEY_MODE, Mode.LIKELIHOOD);     
    params.put(KEY_USE_MOVING_AVG, true);    
    params.put(KEY_WINDOW_SIZE, 10);    
    params.put(KEY_IS_WEIGHTED, true);    
    
    Anomaly anomalyComputer = Anomaly.create(params);    
    
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