Fluctuations in the boundary region of the Alcator C-Mod tokamak have been analyzed using gas puff imaging data from a set of Ohmically heated plasma density scan experiments. It is found that the relative fluctuation amplitudes are modest and close to normally distributed at the separatrix but become increasingly larger and skewed towards the main chamber wall. The frequency power spectra are ...

In this paper, we propose a novel data-driven approach for removing trends (detrending) from nonstationary, fractal and multifractal time series. We consider real-valued time series relative to measurements of an underlying dynamical system that evolves through time. We assume that such a dynamical process is predictable to a certain degree by means of a class of recurrent networks called Echo ...

In this paper, we propose <i>PCKID</i>, a novel, robust, kernel function for spectral clustering, specifically designed to handle incomplete data. By combining posterior distributions of Gaussian Mixture Models for incomplete data on different scales, we are able to learn a kernel for incomplete data that does not depend on any critical hyperparameters, unlike the commonly used RBF kernel. To evaluate ...

This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other ...

In the vicinity of the Snøhvit hydrocarbon reservoir in the Hammerfest Basin a number of fluid flow phenomena occur, e.g. free gas accumulations, pockmarks and potential indicators of gas hydrates.The presence of shallow gas may cause major blowouts during drilling. To reduce the risk, it is important to locate the shallow gas and gas hydrates. CO2 has been injected into the Snøhvit reservoir since ...

The behavior of the autumn and winter weather pattern over Europe and Eurasia was investigated during two periods of high and low ice concentration in September over the Kara-Siberian sea. A statistically significant anomalous energy flux from the east Siberian sea to the atmosphere was detected during October of low ice years. Furthermore, an anomalous behavior in the atmospheric circulation was ...

In this thesis, the reflectance was measured for angles from 10 deg to 80 deg for different n-type silicon based solar cells and for solar absorbers. The measurements were done with unpolarized, p polarized and s polarized light. The reflectance results show that both the solar cells and solar absorbers perform well under small variation from perpendicular angle well but as the angle of incidence ...

Many stars are known to have dust disks, which are created through collisions between planetesimals, comparable to comets and asteroids in our solar system. Cosmic dust around a star absorbs electromagnetic radiation and re-radiates at a longer wavelength, determined by its temperature. The thermal emission of the dust can be observed. In certain systems, including the solar system, some of the dust ...

Since 1999, the Pine Wood Nematode (PWN) has spread, infected and damaged growing areas of pine forest in Portugal. The pest is subject to strict quarantine measures, that require forest owners to register, fell and dispose of infected trees. As remote sensing from satellites provides repetitive and consistent data sets with high temporal resolution and large spatial coverage, a surveillance based ...

Anthropogenic greenhouse gas emissions alter the planet's energy balance and cause heating of the surface and oceans. Estimates of the implications of continued emissions are necessary to assess the severity of the situation. The transient climate response (TCR) is a measure of the climate's response to a continued increase in CO2 concentration, and indicates how much the temperature will increase ...