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Search Publications by: Andrew L Rukhin (Fed)

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Displaying 26 - 50 of 93

Estimating Common Parameters in Heterogeneous Random Effects Models

April 13, 2011
Author(s)
Andrew L. Rukhin
A question of fundamental importance for meta-analysis of heterogeneous data studies is how to form a best consensus estimator of common parameters, and what uncertainty to attach to the estimate. This issue is addressed for a class of unbalanced linear

Limit of detection determination for censored samples.

January 11, 2011
Author(s)
Andrew L. Rukhin, Daniel V. Samarov
The problem of setting the limit of detection is considered for censored samples and heterogeneous errors. After formal definitions of the critical level and of the method detection limit, we introduce simplified maximum likelihood-type estimators. The

Reducing Data Nonconformity in Linear Models

January 3, 2011
Author(s)
Andrew L. Rukhin
Stein phenomenon Summary Several procedures designed to reduce nonconformity in interlaboratory studies by shrinking data toward a consensus matrix weighted mean are suggested. Some of them are shown to have a smaller quadratic risk than the vector sample

Laplace Random Effects Models for Interlaboratory Studies

November 25, 2010
Author(s)
Andrew L. Rukhin, Antonio M. Possolo
A model is introduced for measurements obtained in collaborative interlaboratory studies, comprising measurement errors and random laboratory effects that have Laplace distributions, possibly with heterogeneous, laboratory-specific variances. Estimators

A Statistical Test Suite for Random and Pseudorandom Number Generators for Cryptographic Applications

September 16, 2010
Author(s)
Lawrence E. Bassham, Andrew L. Rukhin, Juan Soto, James R. Nechvatal, Miles E. Smid, Stefan D. Leigh, M Levenson, M Vangel, Nathanael A. Heckert, D L. Banks
This paper discusses some aspects of selecting and testing random and pseudorandom number generators. The outputs of such generators may be used in many cryptographic applications, such as the generation of key material. Generators suitable for use in

Confidence Regions for Parameters of Linear Models

April 1, 2010
Author(s)
Andrew L. Rukhin
A method is suggested for constructing a conservative confidence region for the parameters of a general linear model. In meta-analytical applications, when the results of independent but heterogeneous studies are to be combined, this region can be employed

Conservative Confidence Ellipsoids for Linear Model Parameters

December 1, 2009
Author(s)
Andrew L. Rukhin
This paper studies properties of conservative confidence ellipsoids for parameters of a general linear model. These regions are obtained on the basis of a linear estimator when only a vague knowledge of (heterogeneous) error variances is available. The

A Statistic That Identifies Errant Standard Preparation and Instrument Non-linearity Demonstrated With Mercury Standards Prepared by Blending NIST Fossil Fuel CRMs of Similar Matrices

November 16, 2009
Author(s)
Bruce S. MacDonald, John L. Molloy, Stefan D. Leigh, William R. Kelly, Andrew L. Rukhin
Interval-repeatability (Ir) is a statistic that users of certified reference materials (CRMs) may employ as a quality control check to identify incorrectly prepared working standards or nonlinear instrument response over a targeted concentration interval

Weighted Means Statistics in Interlaboratory Studies

May 6, 2009
Author(s)
Andrew L. Rukhin
The usefulness of weighted means statistics as a consensus mean estimator in collaborative studies is discussed. A random effects model designed to combine information from several sourcesis employed to justify their appeal to metrologists. Some methods of

Identities for Negative Moments of Quadratic Forms in Normal Variables

April 15, 2009
Author(s)
Andrew L. Rukhin
Two formulae for the central inverse moments of a Quadratic form in normal variables and of the ratio forms are established. They relate the quadratic form determined by a positive definite matrix to that defined by the inverse matrix.

Report on Acceleration Comparison SIM.AUV.V-K1 - Draft B

March 20, 2009
Author(s)
David J. Evans, Adriana Hornikova, Stefan D. Leigh, Andrew L. Rukhin, William E. Strawderman
The first regional key comparison in vibration conducted under the auspices of the Inter-American System of Metrology (SIM) was begun in 1996. The comparison was registered with the International Bureau of Weights and Measures (BIPM) through the