Estimating log models: to transform or not to transform?

Estimating log models: to transform or not to transform?

Health economists often use log models to deal with skewed outcomes, such as health utilization or health expenditures. The literature provides a number of alternative estimation approaches for log models, including ordinary least-squares on ln(y) and generalized linear models. This study examines how well the alternative estimators behave econometrically in terms of bias and precision when the...

To transform or not to transform: using generalized linear mixed models to analyse reaction time data

Linear mixed-effect models (LMMs) are being increasingly widely used in psychology to analyse multi-level research designs. This feature allows LMMs to address some of the problems identified by Speelman and McGann (2013) about the use of mean data, because they do not average across individual responses. However, recent guidelines for using LMM to analyse skewed reaction time (RT) data collect...

Folic Acid Supplementation: to Advise or not to Advise?

Robust Image Registration Using Log-Polar Transform

This paper describes a hierarchical image registration algorithm for affine motion recovery. The algorithm estimates the affine transformation parameters necessary to register any two digital images misaligned due to rotation, scale, shear, and translation. The parameters are computed iteratively in a coarse-to-fine hierarchical framework using a variation of the Levenberg-Marquadt nonlinear le...

An O(log n) pyramid hough transform

4h.,nas'c'I his paper describes a divide-and-conquer Hough transtornr technique for detecting a given number of straight edges or lines in an image, This technique is designed for implementation on a pyramid of processors, and requires only O(log a) computational steps for an image of size n x,t ords : pyramids, Hough transform, divide-and-conquer. The Hough transform is a technique for detecti...