de.lmu.ifi.dbs.elki.algorithm.outlier.distance

Class DBOutlierDetection<O>

java.lang.Object

de.lmu.ifi.dbs.elki.algorithm.AbstractAlgorithm<R>

de.lmu.ifi.dbs.elki.algorithm.AbstractDistanceBasedAlgorithm<O,OutlierResult>

de.lmu.ifi.dbs.elki.algorithm.outlier.distance.AbstractDBOutlier<O>

de.lmu.ifi.dbs.elki.algorithm.outlier.distance.DBOutlierDetection<O>

Type Parameters:

O - the type of DatabaseObjects handled by this Algorithm

All Implemented Interfaces:

Algorithm, DistanceBasedAlgorithm<O>, OutlierAlgorithm

@Title(value="DBOD: Distance Based Outlier Detection")
 @Description(value="If the D-neighborhood of an object contains only very few objects (less than (1-p) percent of the data) this object is flagged as an outlier")
 @Reference(authors="E.M. Knorr, R. T. Ng",
           title="Algorithms for Mining Distance-Based Outliers in Large Datasets",
           booktitle="Procs Int. Conf. on Very Large Databases (VLDB\'98), New York, USA, 1998")
 @Alias(value="de.lmu.ifi.dbs.elki.algorithm.outlier.DBOutlierDetection")
public class DBOutlierDetection<O>
extends AbstractDBOutlier<O>

Simple distanced based outlier detection algorithm. User has to specify two parameters An object is flagged as an outlier if at least a fraction p of all data objects has a distance above d from c Reference:

E.M. Knorr, R. T. Ng:
Algorithms for Mining Distance-Based Outliers in Large Datasets,
In: Procs Int. Conf. on Very Large Databases (VLDB'98), New York, USA, 1998.

This paper presents several Distance Based Outlier Detection algorithms. Implemented here is a simple index based algorithm as presented in section 3.1.

Author:

Lisa Reichert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DBOutlierDetection.Parameterizer<O> Parameterization class.

Field Summary

Fields

Modifier and Type	Field and Description
private static Logging	LOG The logger for this class.
private double	p Density threshold percentage p.

Fields inherited from interface de.lmu.ifi.dbs.elki.algorithm.DistanceBasedAlgorithm

DISTANCE_FUNCTION_ID

Constructor Summary

Constructors

Constructor and Description
DBOutlierDetection(DistanceFunction<O> distanceFunction, double d, double p) Constructor with actual parameters.

Method Summary

Modifier and Type	Method and Description
protected DoubleDataStore	computeOutlierScores(Database database, Relation<O> relation, double neighborhoodSize) computes an outlier score for each object of the database.
protected Logging	getLogger() Get the (STATIC) logger for this class.

Methods inherited from class de.lmu.ifi.dbs.elki.algorithm.outlier.distance.AbstractDBOutlier

getInputTypeRestriction, run

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

getDistanceFunction

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.

p

private double p

Density threshold percentage p.

Constructor Detail

DBOutlierDetection

public DBOutlierDetection(DistanceFunction<O> distanceFunction,
                          double d,
                          double p)

Constructor with actual parameters.

Parameters:

distanceFunction - distance function parameter

d - distance query radius

p - percentage parameter

Method Detail

computeOutlierScores

protected DoubleDataStore computeOutlierScores(Database database,
                                               Relation<O> relation,
                                               double neighborhoodSize)

Description copied from class: AbstractDBOutlier

computes an outlier score for each object of the database.

Specified by:

computeOutlierScores in class AbstractDBOutlier<O>

Parameters:

database - Database

relation - Relation

neighborhoodSize - distance

Returns:

computed scores

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