We discuss the use of fixed and random effects models in the context of educational research and set out the assumptions behind the two modelling approaches. To illustrate the issues that should be considered when choosing between these approaches, we analyse the determinants of pupil achievement in primary school, using data from the Avon Longitudinal Study of Parents and Children. We conclude...

An alternative to the classical mixedmodel with normal random effects is to use a Dirichlet process to model the random effects. Such models have proven useful in practice, and we have observed a noticeable variance reduction, in the estimation of the fixed effects, when the Dirichlet process is used instead of the normal. In this paper we formalize this notion, and give a theoretical justifica...

In this paper I discuss economic processes that may give rise to spatial patterns in data, and explore the relative merits of alternative modeling approaches when data are spatially correlated. Specifically, I present an estimation scheme that allows for spatial random effects, and focus attention on cases in which such a framework may be preferred to the more general fixed effects framework th...

field observations of the incurred damages to the buildings and bridges due to earthquakes in near field show there are various failure modes which are in relation to the forces caused by vertical component. while vertical component of earthquake for ordinary buildings in most seismic regulations and standards is not considered. therefore, in the current study the effects of vertical and horizo...

the exposure of workers to magnetic field that occur in aluminum reduction potrooms has been studied. the pattern of magnetic field intensity has been demonstrated along the shop. it has clearly been shown that the personnel working near the pots are exposed to 20-to 1000-gauss magnetic field. to set limits of exposure to magnetic fields, the literature on the biological effects of stationary m...

In this paper, we introduce a model-based method for clustering multiple curves or functionals under spatial dependence specified up to a set of unknown parameters. The functionals are decomposed using a semi-parametric model where the fixed effects account for the large-scale clustering association and the random effects for the small scale spatialdependence variability. The clustering model a...

the use of magnetic fields in targeted drug delivery, especially for treatment of cancers and tumoral regions, is one of the significant techniques in the field of modern methods of treatment. considering that many vital biological tissues have been located deep in the body, then for targeted drug delivery and effective treatment in these tissues, it is required to bring therapeutic agent to th...