de.lmu.ifi.dbs.elki.algorithm.outlier.meta
Class FeatureBagging

java.lang.Object
  de.lmu.ifi.dbs.elki.algorithm.AbstractAlgorithm<OutlierResult>
      de.lmu.ifi.dbs.elki.algorithm.outlier.meta.FeatureBagging

All Implemented Interfaces:

Algorithm, OutlierAlgorithm, InspectionUtilFrequentlyScanned, Parameterizable

@Title(value="Feature Bagging for Outlier Detection")
@Reference(title="Feature Bagging for Outlier Detection",
           authors="A. Lazarevic, V. Kumar",
           booktitle="Proc. of the 11th ACM SIGKDD international conference on Knowledge discovery in data mining",
           url="http://dx.doi.org/10.1145/1081870.1081891")
public class FeatureBagging
extends AbstractAlgorithm<OutlierResult>
implements OutlierAlgorithm

A simple ensemble method called "Feature bagging" for outlier detection.

Since the proposed method is only sensible to run on multiple instances of the same algorithm (due to incompatible score ranges), we do not allow using arbitrary algorithms.

Reference:
A. Lazarevic, V. Kumar: Feature Bagging for Outlier Detection
In: Proc. of the 11th ACM SIGKDD international conference on Knowledge discovery in data mining

Nested Class Summary

static class

FeatureBagging.Parameterizer Parameterization class.

Field Summary

protected boolean	breadth Cumulative sum or breadth first combinations
private int	k The parameters k for LOF.
private static Logging	logger The logger for this class.
protected int	num Number of instances to use
private Random	RANDOM Random number generator for subspace choice

Constructor Summary

FeatureBagging(int k, int num, boolean breadth, Long seed)
Constructor.

Method Summary

TypeInformation[]	getInputTypeRestriction() Get the input type restriction used for negotiating the data query.
protected Logging	getLogger() Get the (STATIC) logger for this class.
private BitSet	randomSubspace(int alldim, int mindim, int maxdim) Choose a random subspace
OutlierResult	run(Relation<NumberVector<?,?>> relation) Run the algorithm on a data set.

Methods inherited from class de.lmu.ifi.dbs.elki.algorithm.AbstractAlgorithm

makeParameterDistanceFunction, run

Methods inherited from class java.lang.Object

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

Methods inherited from interface de.lmu.ifi.dbs.elki.algorithm.outlier.OutlierAlgorithm

run

Field Detail

logger

private static final Logging logger

The logger for this class.

num

protected int num

Number of instances to use

breadth

protected boolean breadth

Cumulative sum or breadth first combinations

RANDOM

private Random RANDOM

Random number generator for subspace choice

k

private int k

The parameters k for LOF.

Constructor Detail

FeatureBagging

public FeatureBagging(int k,
                      int num,
                      boolean breadth,
                      Long seed)

Constructor.

Parameters:

k - k Parameter for LOF

num - Number of subspaces to use

breadth - Flag for breadth-first merging

Method Detail

run

public OutlierResult run(Relation<NumberVector<?,?>> relation)

Run the algorithm on a data set.

Parameters:

relation - Relation to use

Returns:

Outlier detection result

randomSubspace

private BitSet randomSubspace(int alldim,
                              int mindim,
                              int maxdim)

Choose a random subspace

Parameters:

alldim - Number of total dimensions

mindim - Minimum number to choose

maxdim - Maximum number to choose

Returns:

Subspace as bits.

getLogger

protected Logging getLogger()

Description copied from class: AbstractAlgorithm

Get the (STATIC) logger for this class.

Specified by:

getLogger in class AbstractAlgorithm<OutlierResult>

Returns:

the static logger

getInputTypeRestriction

public TypeInformation[] getInputTypeRestriction()

Description copied from class: AbstractAlgorithm

Get the input type restriction used for negotiating the data query.

Specified by:

getInputTypeRestriction in interface Algorithm

Specified by:

getInputTypeRestriction in class AbstractAlgorithm<OutlierResult>

Returns:

Type restriction