Measurement Biases in Pseudo Steady-State Processes Sriram Devanathan, Stephen B. Vardeman and Derrick K. Rollins, Sr. Department of Chemical Engineering, Iowa State University, Ames, Iowa 50011 Departments of Statistics, Ames, Iowa 50011 Department of Industrial and Manufacturing Systems and Engineering, Ames, Iowa 50011 *Author to whom correspondence should be sent Abstract Two new approaches...

Current practice in Quantitative Structure Activity Relationship (QSAR) methods usually involves generating a great number of chemical descriptors and then cutting them back with variable selection techniques. Variable selection is an effective method to reduce the dimensionality but may discard some valuable information. This paper introduces Locally Linear Embedding (LLE), a local non-linear ...

J. S. Buzas Department of Statistics North Carolina State University Raleigh, NC 27695 We describe an approach to instrumental variable estimation in binary regression measurement error models. The method entails constructing an approximate mean model for the binary response as a function of the measured predictor, the instrument and any covariates in the model. Estimates are obtained by exploi...

The conformational behaviour of a prototype helical molecule, [6]helicene, and its derivatives was studied in solution and the solid state. Available crystal structures of [6]helicene revealed surprisingly large flexibility of this molecule and variable-temperature NMR experiments provided unusual temperature dependence of chemical shifts of hydrogen, carbon and fluorine atoms in the peripheral...

chemical methods ( actinometry ) depend on the measurement of the extent to which a chemical reaction occurs under the influence of uv light. two chemical actinometers have been used in this research. in one method, the mixtures of potassium peroxidisuiphate butanol solutions were irradiated for various time intervals, and ph-changes were determined. a linear relationship was observed between t...

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Researchers are often interested in testing for measurement invariance with respect to an ordinal auxiliary variable such as age group, income class, or school grade. In a factor-analytic context, these tests are traditionally carried out via a likelihood ratio test statistic comparing a model where parameters differ across groups to a model where parameters are equal across groups. This test n...

The first interferometric measurements of temporalcoherence length variation with numerical aperture (NA) are described for 650 nm, resonant-cavity light-emitting diodes (LEDs) agreeing with spectrally derived results. The interferometrically measured coherence length (22 m to 32 m) reduced by 37% for a 0.42 increase in NA. For a larger range of NA (0–1), this would give coherence lengths (10 m...

This article focuses on variable selection for partially linear models when the covariates are measured with additive errors. We propose two classes of variable selection procedures, penalized least squares and penalized quantile regression, using the nonconvex penalized principle. The first procedure corrects the bias in the loss function caused by the measurement error by applying the so-call...