@article{kim_boos_2004, title={Variance estimation in spatial regression using a non-parametric semivariogram based on residuals}, volume={31}, ISSN={["0303-6898"]}, DOI={10.1111/j.1467-9469.2004.02-025.x}, abstractNote={Abstract.  The empirical semivariogram of residuals from a regression model with stationary errors may be used to estimate the covariance structure of the underlying process. For prediction (kriging) the bias of the semivariogram estimate induced by using residuals instead of errors has only a minor effect because the bias is small for small lags. However, for estimating the variance of estimated regression coefficients and of predictions, the bias due to using residuals can be quite substantial. Thus we propose a method for reducing this bias. The adjusted empirical semivariogram is then isotonized and made conditionally negative‐definite and used to estimate the variance of estimated regression coefficients in a general estimating equations setup. Simulation results for least squares and robust regression show that the proposed method works well in linear models with stationary correlated errors.}, number={3}, journal={SCANDINAVIAN JOURNAL OF STATISTICS}, author={Kim, HJ and Boos, DD}, year={2004}, month={Sep}, pages={387–401} }
 @article{cowell_kim_humaljoki_berek_kepler_1999, title={Enhanced evolvability in immunoglobulin V genes under somatic hypermutation}, volume={49}, ISSN={["0022-2844"]}, DOI={10.1007/PL00006530}, abstractNote={Darwinian theory requires that mutations be produced in a nonanticipatory manner; it is nonetheless consistent to suggest that mutations that have repeatedly led to nonviable phenotypes would be introduced less frequently than others-if under appropriate genetic control. Immunoglobulins produced during infection acquire point mutations that are subsequently selected for improved binding to the eliciting antigen. We and others have speculated that an enhancement of mutability in the complementarity-determining regions (CDR; where mutations have a greater chance of being advantageous) and/or decrement of mutability in the framework regions (FR; where mutations are more likely to be lethal) may be accomplished by differential codon usage in concert with the known sequence specificity of the hypermutation mechanism. We have examined 115 nonproductively rearranged human Ig sequences. The mutation patterns in these unexpressed genes are unselected and therefore directly reflect inherent mutation biases. Using a chi2 test, we have shown that the number of mutations in the CDRs is significantly higher than the number of mutations found in the FRs, providing direct evidence for the hypothesis that mutations are preferentially targeted into the CDRs.}, number={1}, journal={JOURNAL OF MOLECULAR EVOLUTION}, author={Cowell, LG and Kim, HJ and Humaljoki, T and Berek, C and Kepler, TB}, year={1999}, month={Jul}, pages={23–26} }
 @article{cho_kim_littler_miller_lee_lindsey_1999, title={Rational synthesis of trans-substituted porphyrin building blocks containing one sulfur or oxygen atom in place of nitrogen at a designated site}, volume={64}, ISSN={["0022-3263"]}, DOI={10.1021/jo9909305}, abstractNote={The use of heteroatom-substituted porphyrins in bioorganic and materials chemistry requires the ability to position a variety of substituents in a controlled manner about the porphyrin periphery. We describe a rational route to trans-AB2C-type porphyrins bearing one oxygen atom (N3O) or one sulfur atom (N3S) in a designated location in the porphyrin core. The synthesis involved four stages:  (1) Acid-catalyzed condensation of a furyl- or thienylcarbinol in excess pyrrole afforded the aryl-substituted furyl- or thienylpyrromethane in high yield. (2) Treatment of the furyl- or thienylpyrromethane with an acid chloride catalyzed by SnCl4 or AlCl3 afforded the corresponding diketo product. (3) Reduction with NaBH4 in alcoholic solvents gave the furyl- or thienylpyrromethanediols. (4) Reaction of a furylpyrromethanediol, thienylpyrromethanediol, or dipyrromethanediol with a dipyrromethane in a one-flask process of condensation followed by oxidation gave the corresponding porphyrin. Reaction conditions previous...}, number={21}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Cho, WS and Kim, HJ and Littler, BJ and Miller, MA and Lee, CH and Lindsey, JS}, year={1999}, month={Oct}, pages={7890–7901} }