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Displaying 51 - 75 of 93

Fiducial approach for assessing agreement between two instruments

July 9, 2008
Author(s)
Chih-Ming Wang, Hariharan K. Iyer
This paper presents an approach for making inferences about the intercept and the slope of a linear regression model with both variables subject to measurement errors. The approach is based on the principle of fiducial inference. A procedure is presented

Uncertainty Analysis for Vector Measurands Using Fiducial Inference

January 1, 2006
Author(s)
Chih-Ming Wang, Hariharan K. Iyer
This paper presents a method for constructing uncertainty regions for a vector measurand in the presence of both type-A and type-B errors. The method is based on the principle of fiducial inference and generally requires a Monte Carlo approach for

Uncertainty in Reference Values for the Charpy V-notch Verification Program

May 1, 2005
Author(s)
Jolene D. Splett, Chih-Ming Wang
We present a method for computing the combined standard uncertainty for reference values used in the Charpy machine verification program administered by the National Institute of Standards and Technology. The technique is compliant with the ISO GUM and

Propagation of Uncertainties in Measurements Using Structural Inference

March 21, 2005
Author(s)
Hariharan K. Iyer, Chih-Ming Wang
The ISO Guide to the Expression of Uncertainty in Measurement (GUM) recommends the use of a first-order Taylor series expansion for propagating errors and uncertainties. The GUM also permits the use of other analytical or numerical methods when the

On Higher Order Corrections for Propagating Uncertainties

January 1, 2005
Author(s)
Chih-Ming Wang, Hariharan K. Iyer
The ISO Guide to the Expression of Uncertainty in Measurement (GUM) recommends the use of a first-order Taylor series expansion for propagating errors and uncertainties. The GUM also suggests the use of a second-order Taylor series approximation for

Propagation of uncertainties in measurements using generalized influence

January 1, 2005
Author(s)
Hariharan K. Iyer, Chih-Ming Wang
The ISO Guide to the Expression of Uncertainty in Measurement (GUM) recommends the use of a first- order Taylor series expansion for propagating errors and uncertainties. The GUM also permits the use of "other analytical or numerical methods" when the

Models and Confidence Intervals for True Values in Interlaboratory Trials

December 6, 2004
Author(s)
Hariharan K. Iyer, Chih-Ming Wang, T Mathew
We consider the one-way random effects model with unequal sample sizes and heterogeneous variances. Using the method of generalized confidence intervals, we develop a new confidence interval procedure for the mean. Additionally, we investigate two

An Optimal Vector-Network-Analyzer Calibration Algorithm

December 1, 2003
Author(s)
Dylan Williams, Chih-Ming Wang, Uwe Arz
We present an iterative algorithm for calibrating vector network analyzers based on orthogonal distance regression. The algorithm features a robust, yet efficient, search algorithm, a complete error analysis that includes both random and systematic errors

Adaptive Characterization of Jitter Noise in Sampled High-Speed Signals

October 1, 2003
Author(s)
Kevin J. Coakley, Chih-Ming Wang, Paul D. Hale, Tracy S. Clement
We estimate the root-mean-square (RMS) value of timing jitter noise in simulated signals similar to measured high-speed sampled signals. The simulated signals are contaminated by additive noise, timing jitter noise, and time shift errors. Before estimating

The NIST Traceable Reference Material Program for Wavelength Reference Absorption Cells

August 1, 2003
Author(s)
Timothy J. Drapela, Sarah L. Gilbert, William C. Swann, Chih-Ming Wang
A program is described by which commercially produced wavelength-calibration gas-absorption cells may be related to primary standards maintained by the National Institute of Standards and Technology (NIST) and Standard Reference Materials produced by NIST

A Statistical Model for Cladding Diameter of Optical Fibers

April 1, 2003
Author(s)
Chih-Ming Wang, Timothy J. Drapela
The National Institute of Standards and Technology has developed a contact micrometer for accurate measurement of optical-fiber outer diameter. The contact micrometer is used to measure reference fibers which are artifacts used by the telecommunications

Interlaboratory Comparison of Magnetic Thin Film Measurements

April 1, 2003
Author(s)
F C. Da silva, Chih-Ming Wang, D P. Pappas
A potential low magnetic moment standard reference material (SRM) was studied in an interlaboratory comparison. The mean and the standard deviation of the saturation moment m/s, the remanent moment m/ r, and the intrinsic coercivity H/c of nine samples

Accuracy of AlGaAs Rates and Composition Determination Using RHEED Oscillations

September 1, 2002
Author(s)
Todd E. Harvey, Kristine A. Bertness, Chih-Ming Wang, Jolene Splett
Reflection high-energy electron diffraction (RHEED) oscillations are widely used in molecular beam epitaxy (MBE) as a technique to calibrate material growth rates. The growth rates are used to predict the composition of the following growth run. For many

Effects of Noise Level in Fitting In-Situ Optical Reflectance Spectroscopy Data

September 1, 2002
Author(s)
Chih-chiang Fu, Kristine A. Bertness, Chih-Ming Wang
We discuss the combination of noise level and scaling factor accuracy needed in optical reflectance spectroscopy data in order to obtain accurate parameters by fitting simulated Optical Reflectance Spectroscopy data curves with different noise level.

Uncertainty of Oscilloscope Timebase Distortion Estimate

February 1, 2002
Author(s)
Chih-Ming Wang, Paul D. Hale, Kevin Coakley, Tracy S. Clement
We study several problems related to the characterization of the timebase in high-speed sampling oscilloscopes. First, we examine the bias of using the method of the first-order approximation to estimate the additive and time jitter noises, and present a