Package moa.classifiers.oneclass

Class HSTreeNode

java.lang.Object

moa.classifiers.oneclass.HSTreeNode

All Implemented Interfaces:

java.io.Serializable

public class HSTreeNode
extends java.lang.Object
implements java.io.Serializable

A node in an HSTree. Based on the work S. C. Tan, K. M. Ting, and T. F. Liu, “Fast anomaly detection for streaming data,” in IJCAI Proceedings-International Joint Conference on Artificial Intelligence, 2011, vol. 22, no. 1, pp. 1511–1516. Made use of by HSTrees.java.

Author:

Richard Hugh Moulton

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
HSTreeNode(double[] min, double[] max, int k, int maxDepth)	Constructor for an HSTreeNode.

Method Summary

Modifier and Type	Method	Description
protected void	printNode()	Prints this node to string and, if it is an internal node, prints its children nodes as well.
double	score(Instance inst, int sizeLimit)	If this node is a leaf node or it has a mass profile of less than sizeLimit, this returns the anomaly score for the argument instance.
void	updateMass(Instance inst, boolean referenceWindow)	Update the mass profile of this node.
void	updateModel()	Update the node's model by setting the latest window's mass profile as the reference window's mass profile, resetting the latest window's mass profile to zero and updating any subordinates nodes' models.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HSTreeNode

public HSTreeNode(double[] min,
                  double[] max,
                  int k,
                  int maxDepth)

Constructor for an HSTreeNode.

Parameters:

min - the minimum values of the attributes for this node's workspace

max - the maximum values of the attributes for this node's workspace

k - the depth of this node in the HSTree

maxDepth - the maximum depth of this HSTree

Method Detail

updateMass

public void updateMass(Instance inst,
                       boolean referenceWindow)

Update the mass profile of this node.

Parameters:

inst - the instance being passed through the HSTree.

referenceWindow - if the HSTree is in the initial reference window: true, else: false

updateModel

public void updateModel()

Update the node's model by setting the latest window's mass profile as the reference window's mass profile, resetting the latest window's mass profile to zero and updating any subordinates nodes' models.

score

public double score(Instance inst,
                    int sizeLimit)

If this node is a leaf node or it has a mass profile of less than sizeLimit, this returns the anomaly score for the argument instance. Otherwise this node determines which of its subordinate nodes the argument instance belongs to and asks it provide the anomaly score.

Parameters:

inst - the instance being passed through the tree

sizeLimit - the minimum mass profile for a node to calculate the argument instance's anomaly score

Returns:

the argument instance's anomaly score (r * 2^depth)

printNode

protected void printNode()

Prints this node to string and, if it is an internal node, prints its children nodes as well. Useful for debugging the entire tree structure.