de.lmu.ifi.dbs.elki.utilities.scaling.outlier

Class SqrtStandardDeviationScaling

java.lang.Object

de.lmu.ifi.dbs.elki.utilities.scaling.outlier.SqrtStandardDeviationScaling

All Implemented Interfaces:

Parameterizable, OutlierScalingFunction, ScalingFunction

@Reference(authors="H.-P. Kriegel, P. Kr\u00f6ger, E. Schubert, A. Zimek",
           title="Interpreting and Unifying Outlier Scores",
           booktitle="Proc. 11th SIAM International Conference on Data Mining (SDM), Mesa, AZ, 2011",
           url="http://siam.omnibooksonline.com/2011datamining/data/papers/018.pdf")
public class SqrtStandardDeviationScaling
extends Object
implements OutlierScalingFunction

Scaling that can map arbitrary values to a probability in the range of [0:1]. Transformation is done using the formulas y = sqrt(x - min) newscore = max(0, erf(lambda * (y - mean) / (stddev * sqrt(2)))) Where min and mean can be fixed to a given value, and stddev is then computed against this mean.

Nested Class Summary

Nested Classes

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

Field Summary

Fields

Modifier and Type	Field and Description
(package private) double	factor Scaling factor to use (usually: Lambda * Stddev * Sqrt(2))
protected Double	lambda Field storing the lambda value
static OptionID	LAMBDA_ID Parameter to specify the lambda value Key: -sqrtstddevscale.lambda
(package private) Double	mean Mean to use
static OptionID	MEAN_ID Parameter to specify a fixed mean to use.
(package private) Double	min Min to use
static OptionID	MIN_ID Parameter to specify the fixed minimum to use.

Constructor Summary

Constructors

Constructor and Description
SqrtStandardDeviationScaling(Double min, Double mean, Double lambda) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
double	getMax() Get maximum resulting value.
double	getMin() Get minimum resulting value.
double	getScaled(double value) Transform a given value using the scaling function.
void	prepare(OutlierResult or) Prepare is called once for each data set, before getScaled() will be called.

Methods inherited from class java.lang.Object

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

Field Detail

MIN_ID

public static final OptionID MIN_ID

Parameter to specify the fixed minimum to use.

Key: -sqrtstddevscale.min

MEAN_ID

public static final OptionID MEAN_ID

Parameter to specify a fixed mean to use.

Key: -sqrtstddevscale.mean

LAMBDA_ID

public static final OptionID LAMBDA_ID

Parameter to specify the lambda value

Key: -sqrtstddevscale.lambda

lambda

protected Double lambda

Field storing the lambda value

min

Double min

Min to use

mean

Double mean

Mean to use

factor

double factor

Scaling factor to use (usually: Lambda * Stddev * Sqrt(2))

Constructor Detail

SqrtStandardDeviationScaling

public SqrtStandardDeviationScaling(Double min,
                            Double mean,
                            Double lambda)

Constructor.

Parameters:

min -

mean -

lambda -

Method Detail

getScaled

public double getScaled(double value)

Description copied from interface: ScalingFunction

Transform a given value using the scaling function.

Specified by:

getScaled in interface ScalingFunction

Parameters:

value - Original value

Returns:

Scaled value

prepare

public void prepare(OutlierResult or)

Description copied from interface: OutlierScalingFunction

Prepare is called once for each data set, before getScaled() will be called. This function can be used to extract global parameters such as means, minimums or maximums from the Database, Result or Annotation.

Specified by:

prepare in interface OutlierScalingFunction

Parameters:

or - Outlier result to use

getMin

public double getMin()

Description copied from interface: ScalingFunction

Get minimum resulting value. May be Double.NaN or Double.NEGATIVE_INFINITY.

Specified by:

getMin in interface ScalingFunction

Returns:

Minimum resulting value.

getMax

public double getMax()

Description copied from interface: ScalingFunction

Get maximum resulting value. May be Double.NaN or Double.POSITIVE_INFINITY.

Specified by:

getMax in interface ScalingFunction

Returns:

Maximum resulting value.