Academic literature on the topic 'Non-linear repeated measurements'

Types of psychiatric disorders vary with respect to age of onset, temporal continuity, and impact. Life course epidemiology provides powerful tools for understanding these complexities. This discipline broadly distinguishes ‘sensitive period’ and ‘risk accumulation’ models. The former refers to optimum windows for exposure (e.g. early life for some psychoses, in contrast to proximal exposures for depression). Accumulation refers to additive or multiplicative effects of multiple exposures, exemplified by stress process and chain of risk models. The preeminent study design for these approaches is the prospective longitudinal birth cohort study, especially where multiple cohorts help to distinguish period and cohort effects. However, limitations such as balancing the need for repeated versus age-appropriate measurement, and non-random missing data, must be carefully considered. While the statistical workhorse for life course epidemiology is general linear modelling, this discipline also requires advanced tools such as random effects, path, latent class, and latent growth modelling.

Internal sealing of many power plant valves is performed by a metal to metal contact, compatible with severe pressure and temperature conditions of liquid water flow. Contact surfaces are treated by hard alloy coating and lapping in order to enhance sealing properties. However, wavy deformation may occur on the surface because of stress induced during manufacturing and all through the device life, for example as a consequence of thermal shocks. We aim to quantitatively correlate the leakage which results from wavy defects through experimental measurements and predictions obtained from modeling

Experiments were performed to examine the influence of homogeneous magnetic field on convection instability and flows in a layer of magnetic fluid heated from one wide side and cooled from another. The temperature sensors were used for measurement of heat transport across the layer. Visualization of flow patterns was provided by a liquid crystal sheet. The results indicate that with the help of a magnetic field it is possible to control the convection stability, intensity of the heat transfer and the form of convection motions. The interaction of gravitational and magnetic convection mechanism

The reliability of the gas path components (compressor, burners and turbines) of a gas turbine (GT) is usually high when compared with other GT systems such as fuel and control. However, their availability could be relatively low as high downtimes are normally associated with these components when subjected to forced outages. One way of improving availability is by improved maintenance practices that involve applying such approaches as condition based monitoring (CBM). Unfortunately, this cannot be achieved without the existence of a proper instrumentation set that can adequately and repeatedl

In the paper, feed-forward Recurrent Neural Networks with a single hidden layer and trained by using a back-propagation learning algorithm are studied and developed for the simulation of compressor behavior under unsteady conditions. The data used for training and testing the RNNs are both obtained by means of a non-linear physics-based model for compressor dynamic simulation (simulated data) and measured on a multi-stage axial-centrifugal small size compressor (field data). The analysis on simulated data deals with the evaluation of the influence of the number of training patterns and of each