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, 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

Nested Classes

Modifier and Type	Class and Description
static class	FeatureBagging.Parameterizer Parameterization class.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	breadth Cumulative sum or breadth first combinations.
private int	k The parameters k for LOF.
private static Logging	LOG The logger for this class.
protected int	num Number of instances to use.
private RandomFactory	rnd Random number generator for subspace choice.

Constructor Summary

Constructors

Constructor and Description
FeatureBagging(int k, int num, boolean breadth, RandomFactory rnd) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
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, Random rand) Choose a random subspace.
OutlierResult	run(Database database, 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

LOG

private static final Logging LOG

The logger for this class.

num

protected int num

Number of instances to use.

breadth

protected boolean breadth

Cumulative sum or breadth first combinations.

rnd

private RandomFactory rnd

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,
              RandomFactory rnd)

Constructor.

Parameters:

k - k Parameter for LOF

num - Number of subspaces to use

breadth - Flag for breadth-first merging

rnd - Random generator

Method Detail

run

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

Run the algorithm on a data set.

Parameters:

database - Database context

relation - Relation to use

Returns:

Outlier detection result

randomSubspace

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

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