Data sets obtained from quantitative analysis of seventeen pesticides in water samples from a network of irrigation and drainage channels in the Ebro river delta (Catalonia, NE Spain) have been analysed by chemometric and geostatistical methods. Samples were taken at fourteen locations during the main rice-growing season, from May to August 2005. Principal-component analysis enabled investigati...

Exact one-way re-formulations of the Helmholtz equation are useful for waveg-uide problems, since the resulting equations can be eeciently solved as \initial" value problems by range marching methods. Some numerical methods for these re-formulations are reviewed in this paper. This includes a switched method that avoids the singularities of the operators and the large range step methods that gi...

A useful approach for long range computation of the Helmholtz equation in a waveguide is to re-formulate it as the operator diierential Riccati equation for the Dirichlet-to-Neumann (DtN) map. For waveguides with slow range dependence, the piecewise range independent approximation is used to derive a second order range stepping method for this one-way re-formulation. The range marching formulas...

Removal of noise is an important step in the image restoration process, and remains a challenging problem in spite of the sophistication of recent research. Popular approaches can be categorized in various ways, a classical one of which involves minimization of variation in an image. This report presents a comparison of three such classical image denoising methods, all minimizing the variation ...

In this paper, we consider Bayesian estimation and model determination for two-way contingency tables. The analysis is based on partitioning the parameter space of a saturated log-linear model into parameter subspaces identiied by considering the natural symmetries of the data. Prior distributions may then be chosen to respect invariance restrictions required by the available prior information....