K
Kjell Johnson
Researcher at Pfizer
Publications - 43
Citations - 4997
Kjell Johnson is an academic researcher from Pfizer. The author has contributed to research in topics: Random forest & Partial least squares regression. The author has an hindex of 17, co-authored 43 publications receiving 3821 citations. Previous affiliations of Kjell Johnson include West Virginia University & University of Michigan.
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Applied Predictive Modeling
Max Kuhn,Kjell Johnson +1 more
TL;DR: This research presents a novel and scalable approach called “Smartfitting” that automates the very labor-intensive and therefore time-heavy and therefore expensive and expensive process of designing and implementing statistical models for regression models.
Journal ArticleDOI
Peroxynitrite-mediated protein nitration and lipid peroxidation in a mouse model of traumatic brain injury.
TL;DR: Investigation of the role of the ROS, peroxynitrite (PON), in the acute pathophysiology of TBI and its temporal relationship to neurodegeneration in the context of the mouse model of diffuse head injury model indicates that optimal pharmacological inhibition of post-traumatic oxidative damage in TBI may need to combine two functionalities.
Journal ArticleDOI
Three-dimensional lung tumor microenvironment modulates therapeutic compound responsiveness in vitro--implication for drug development.
Jason E. Ekert,Kjell Johnson,Brandy Strake,Jose R. Pardinas,Stephen Jarantow,Robert Perkinson,David C. Colter +6 more
TL;DR: Overall, the 3D spheroid culture changed the cellular response to drugs and growth factors and may more accurately mimic the natural tumor microenvironment.
Journal ArticleDOI
ada: An R Package for Stochastic Boosting
TL;DR: Ada is an R package that implements three popular variants of boosting, together with a version of stochastic gradient boosting, which incorporates a random mechanism at each boosting step showing an improvement in performance and speed in generating the ensemble.
Book ChapterDOI
An Introduction to Feature Selection
Max Kuhn,Kjell Johnson +1 more
TL;DR: This chapter demonstrates the negative effect of extra predictors on a number of models, as well as discussing typical approaches to supervised feature selection such as wrapper and filter methods and the danger of selection bias.