estimating parameter bias uncertainty

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  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    Estim

    atingParameterBia

    sUncertainty

    HowardCastrup,

    Ph.D.

    President,IntegratedSciencesGroup

    MeasurementS

    cienceConferenc

    e

    TrackE,

    Sessio

    n6

    UncertaintyTec

    hniquesandMeth

    ods

    March3,

    2006

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    EstimatingP

    aramete

    rBias

    Unc

    ertainty

    Ke

    yConcepts

    Ty

    peAEstim

    ation

    Ty

    peBEstim

    ation

    Ty

    peBDegre

    esofFree

    dom

    Ty

    peAEstim

    ation

    Ba

    yesianEstimation

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    Estim

    atingParameterBiasUncertainty

    Key

    Concepts

    Measuremen

    tsareAcc

    ompanied

    by

    Measuremen

    tError

    Th

    eFundam

    entalMea

    surement

    Model

    Th

    eMeasurementErro

    r

    meas

    true

    meas

    x

    x

    =

    +

    meas

    bias

    random

    operator

    =

    +

    +

    +

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    Estim

    atingParameterBiasUncertainty

    Typ

    eAEstimation

    Ex

    ample:

    UncertaintyDuetoRandomError:

    Where

    2

    1

    1

    (

    )

    n

    ran

    dom

    i

    i

    u

    x

    x

    =

    =

    sampledv

    alue

    samplemean

    samplesize

    1

    ix

    ith

    x n

    n

    = = = =

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    KeyC

    oncepts

    Typ

    eAEstimation(cont.)

    Co

    nfidenceL

    imitsLforaConfide

    nce

    Le

    velof1

    t/2,

    =t-statisticforasig

    nificancele

    vel

    of

    /2andde

    greesoffreedom

    /2,

    random

    L

    t

    u

    =

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    KeyC

    oncepts

    Typ

    eBEstimation

    Es

    timationPr

    ocedure

    Co

    ntainment

    Limitsand

    Probability

    Un

    certaintyD

    efinition

    BiasDistribut

    ions

    SeeEstimatingandCombiningUncertaintiesand

    AC

    omprehensiveCo

    mparisonofUnce

    rtaintyAnalysisT

    oolsat

    www.i

    sgm

    ax.c

    om/articles_

    papers.h

    tm

    .

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    Type

    BEstimation

    Estimation

    Procedu

    re

    Reversethe

    TypeAEstimation

    Procedure

    EstimateorDevelopCon

    tainmentLim

    its

    ParameterToleranceLimits

    Other

    EstimateaC

    ontainmentProbability

    PercentIn-tolerance

    Confidence

    Level

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    Type

    BEstimation

    Con

    tainmentLimitsand

    Probability

    C

    ontainment

    Limits

    0

    L1

    L2

    f()

    Containm

    ent

    Probabilityp

    TheParameterBiasD

    istribution

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    Type

    BEstimation

    Unc

    ertaintyD

    efinition

    Th

    estandard

    uncertaintyinparameter

    bia

    sisthesta

    ndarddeviationofthe

    bias

    dis

    tribution.

    Ap

    plytheapp

    ropriatedistribution.

    Es

    timatefr

    omL1,L2andp.

    2

    var()

    ()

    f

    d

    =

    var()

    u

    = =

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    Type

    BEstimation

    Bias

    Distributions

    Normal

    Log

    normal

    Uniform(Rectang

    ular)

    Triangular

    Tra

    pezoidal

    Quadratic

    Cosine

    Utility

    U-S

    haped

    SeeDistribu

    tionsforUncertai

    ntyAnalysisat

    www.i

    sgm

    ax.c

    om/articles_papers.h

    tm.

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    BiasD

    istributions

    NormalDistribution

    2

    2

    /2

    1

    ()

    2

    u

    f

    eu

    =

    1

    2

    1

    L

    L

    p

    u

    u

    =

    +

    1

    12

    L

    u

    p

    =

    +

    thepdf

    solveforufrom

    ifL1=L2then

    0

    L1

    L2

    f()

    p

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    BiasD

    istributions

    LognormalDistribution

    Us

    efulforParametersw

    ithAsymmetric

    To

    lerances

    2

    2

    1

    (

    )

    exp

    ln

    2

    (

    )

    2

    q

    f

    qm

    q

    =

    q

    f

    ()

    f

    ()

    2

    2

    3

    (

    )

    (

    1)

    u

    qmm

    me

    =

    =

    Solve

    fornumerica

    lly

    L1

    +L2

    p

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    BiasD

    istributions

    Unif

    orm(Rectangular)Distributio

    n

    1

    ,

    ()

    2 0,

    otherwise,

    a

    a

    f

    a

    =

    3a

    u=

    ,

    La

    L

    a

    p=

    Not

    recommendedforestimatingbiasu

    ncertainty

    -L

    L

    p

    f()

    -a

    a

    0

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    BiasD

    istributions

    TriangularDis

    tribution

    2 2

    (

    )/

    ,

    0

    ()

    (

    )/

    ,

    0

    0,

    othe

    rwise.

    a

    a

    a

    f

    a

    a

    a

    +

    =

    6a

    u=

    ,

    1

    1

    L

    a

    La

    p

    =

    Not

    recommendedforestimatingbiasu

    ncertainty

    -L

    L

    p

    f()

    -a

    a

    0

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    BiasD

    istributions

    Trap

    ezoidalD

    istribution

    ,

    (

    )(

    )

    1

    ,

    ()

    ,

    (

    )(

    )

    0.

    o

    therwise

    b

    b

    a

    a

    bba

    a

    a

    f

    a

    bb

    a

    b

    a

    bba

    +

    +

    =

    +

    +

    2

    2

    3

    a

    b

    u

    +

    =

    2

    0

    2

    L

    a

    aL

    a

    b

    p

    ab

    b

    a

    +

    +

    =

    +

    S

    olveforafrom

    Not

    recommendedforestimatingbiasu

    ncertainty

    f()

    -a

    a

    0

    -L

    L

    p-b

    b

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    BiasD

    istributions

    Qua

    draticDis

    tribution

    2

    3

    1

    (

    /

    )

    ()

    ,

    4 0,

    otherwise

    a

    f

    a

    a

    a

    =

    ,5a

    u=

    3

    3

    2

    0,

    /

    1

    x

    xp

    xL

    a

    +

    =

    =

    Solveforafrom

    f()

    -a

    a

    0

    -L

    L

    p

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    BiasD

    istributions

    Cos

    ineDistrib

    ution

    1

    1

    cos

    ()

    ,

    2 0,

    oth

    erwise

    f

    a

    a

    a

    a

    +

    =

    26

    1

    3a

    u

    =

    sin(

    /

    )

    0,

    a

    La

    ap

    L

    L

    a

    +

    =

    Solveforafrom

    a

    -a

    a

    -a

    -L

    L

    p

    0f()

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    BiasD

    istributions

    UtilityDistribu

    tion

    2

    1

    ,

    |

    |

    1

    (|

    |

    )

    ()

    cos

    ,

    |

    |

    2(

    )

    0,

    |

    |

    ,a

    ab

    a

    f

    a

    b

    a

    b

    ba

    b

    +

    =

    +

    (

    )

    3

    3

    2

    2

    2

    1

    2

    3a

    b

    u

    ba

    ab

    +

    =

    +

    1

    (

    )

    sin

    0

    ba

    L

    a

    L

    p

    ab

    ba

    +

    =

    +

    Solveforafrom

    f()

    -a

    a

    -b

    b

    -L

    L

    0

    p

  • 8/8/2019 Estimating Parameter Bias Uncertainty

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    BiasD

    istributions

    U-ShapedDis

    tribution

    2

    2

    1

    ,

    ()

    0,

    otherwise,

    a

    a

    f

    a