Sample Designs for Watershed Assessment

This article describes two probability sampling approaches to sampling water resources. In the first approach, a complete enumeration of eligible sample units (e.g. stream segments, water bodies, drainage basins) is performed using GIS or paper maps to create a list frame. A probability random sample is then selected from this frame. In the second approach, a two-stage sample is selected. In the first stage, area segments are selected using a probability design, such as stratified sampling. Water resources contained in each segment are enumerated and labeled using field visits or aerial photographs. In a second stage, the water resource or related sampling units (e.g. stream segments, water bodies, measurement points) are selected in each of the segments. Examples of both approaches are presented, and their relative strengths and weaknesses are discussed. Key Words: water resource sampling, GIS frame, area sampling, Markov chain sampling. J.D. Opsomer is Assistant Professor and S.M...

Regularization Methods for Additive Models

This paper tackles the problem of model complexity in the context of additive models. Several methods have been proposed to estimate smoothing parameters, as well as to perform variable selection. Nevertheless

Optimal testing for additivity in multiple nonparametric regression

Additive models, Functional hypothesis testing, Minimax testing, Nonparametric regression, Wavelets,