English
norskFakultet for naturvitenskap og teknologi: Nye registreringer
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The Life and Death of the Recent Global Warming Hiatus Parsimoniously Explained
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-21)The main features of the instrumental global mean surface temperature (GMST) are reasonably well described by a simple linear response model driven by anthropogenic, volcanic and solar forcing. This model acts as a linear long-memory filter of the forcing signal. The physical interpretation of this filtering is the delayed response due to the thermal inertia of the ocean. This description is ... -
Flags of almost affine codes and the two-party wire-tap channel of type II
(Journal article; Tidsskriftartikkel; Manuskript; Peer reviewed; Preprint, 2017-11-15)We describe a two-party wire-tap channel of type II in the framework of almost affine codes. Its cryptological performance is related to some relative profiles of a pair of almost affine codes. These profiles are analogues to relative generalized Hamming weights in the linear case. -
Time series cluster kernel for learning similarities between multivariate time series with missing data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-06)<p>Similarity-based approaches represent a promising direction for time series analysis. However, many such methods rely on parameter tuning, and some have shortcomings if the time series are multivariate (MTS), due to dependencies between attributes, or the time series contain missing data. In this paper, we address these challenges within the powerful context of kernel methods by proposing the ... -
The MAR databases: development and implementation of databases specific for marine metagenomics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-02)We introduce the marine databases; <i>MarRef, MarDB</i> and <i>MarCat</i> (https://mmp.sfb.uit.no/databases/), which are publicly available resources that promote marine research and innovation. These data resources, which have been implemented in the Marine Metagenomics Portal (MMP) (https://mmp.sfb.uit.no/), are collections of richly annotated and manually curated contextual (metadata) and sequence ... -
Kara-Siberian sea ice anomaly and its impact on the atmosphere
(Master thesis; Mastergradsoppgave, 2018-05-15)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 ... -
Analysis of evolving oil spills in full-polarimetric and hybrid-polarity SAR
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-25)Oil spill detection using a time series of images acquired off Norway in June 2015 with the uninhabited aerial vehicle synthetic aperture radar is examined. The relative performance of a set of features derived from quad-polarization versus hybrid-polarity (HP) modes in detection of various types of slicks as they evolve on a high wind driven sea surface is evaluated. It is shown that the HP mode ... -
Angle Dependent Reflectance and Performance of Solar Cells and Absorbers
(Master thesis; Mastergradsoppgave, 2018-05-14)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 ... -
Uncertainty Modeling and Interpretability in Convolutional Neural Networks for Polyp Segmentation.
(Master thesis; Mastergradsoppgave, 2018-05-14)Colorectal cancer is one of the leading causes of cancer-related deaths worldwide, with prevention commonly done through regular colonoscopy screenings. During a colonoscopy, physicians manually inspect the colon of a patient using a camera in search for polyps, which are known to be possible precursors to colorectal cancer. Seeing that a colonoscopy is a manual procedure, it can be susceptible to ... -
Temperature and thermal emission of cosmic dust around the Sun, Vega and Fomalhaut
(Master thesis; Mastergradsoppgave, 2018-05-14)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 ... -
Baneberegninger for støv rundt Sola, Vega og Fomalhaut
(Master thesis; Mastergradsoppgave, 2018-05-14)Observasjoner av Vega og Fomalhaut tyder på at de har støvbelter rundt seg. Avstanden fra stjerna er rundt 0,2 astronomiske enheter (AE) og størrelsen til støvpartiklene varierer fra noen nanometer til noen mikrometer. Slikt støv fins også i solsystemet. Denne oppgaven handler om å beregne banen til slike støvpartikler etter danning. Det antas at støvet påvirkes av tre krefter: gravitasjon, ... -
Forest Health Monitoring by Detection of Biotic Agents in Satellite Images
(Master thesis; Mastergradsoppgave, 2018-06-01)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 ... -
On the Feasibility of Using Twitter Data to Assess the Global Circulation Patterns of Influenza Viruses
(Master thesis; Mastergradsoppgave, 2018-06-01)Having the flu is something that everyone is familiar with, and the influenza season hits every year. The intensity and timing vary from year to year driven by climatic conditions and antigenic evolution, through mechanisms that are only partially understood. Most research agree that the virus originates in East and South-East (E-SE) Asia and spread throughout the world through human movement. In ... -
Constraining Transient Climate Response Using the Historical Temperature Record
(Master thesis; Mastergradsoppgave, 2018-06-01)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 ... -
Survey and simulation of space debris using EISCAT UHF
(Master thesis; Mastergradsoppgave, 2018-06-01)This thesis starts with a review of the evolution of space debris, what is consists of, how it is made, how it is detected and tracked, and why it is such an important topic. Some of the worst collisions have contributed to causing 49% of the total space debris. If the launch rate continues, the "Kessler Syndrome" might become a reality destroying our future outlook for space communication and ... -
Physical Conditions of Fast Glacier Flow: 2. Variable Extent of Anisotropic Ice and Soft Basal Sediment From Seismic Reflection Data Acquired on Store Glacier, West Greenland
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-09)Outlet glaciers of the Greenland Ice Sheet transport ice from the interior to the ocean and contribute directly to sea level rise because discharge and ablation often exceed the accumulation. To develop a better understanding of these fast‐flowing glaciers, we investigate the basal conditions of Store Glacier, a large outlet glacier flowing into Uummannaq Fjord in west Greenland. We use two crossing ... -
Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-21)Marine‐terminating outlet glaciers of the Greenland Ice Sheet make significant contributions to global sea level rise, yet the conditions that facilitate their fast flow remain poorly constrained owing to a paucity of data. We drilled and instrumented seven boreholes on Store Glacier, Greenland, to monitor subglacial water pressure, temperature, electrical conductivity, and turbidity along with ... -
SAR imaging and detection of partially coherent targets
(Master thesis; Mastergradsoppgave, 2018-05-23)A synthetic aperture radar (SAR) achieves a high azimuth resolution by illuminating targets with multiple pulses and using the Doppler history to synthesize a large antenna. When combining the pulses, it is normally assumed that the targets are stationary, and that their reflectivity is independent of time. The topic of this thesis is the processing of SAR images where the the targets have a ... -
Optical nanoscopy of tissue sections
(Master thesis; Mastergradsoppgave, 2018-05-28)The study of organ tissues, namely, histology, is essential for clinical medicine, as it allows the identification of a wide range of diseases. Traditionally, two major techniques, optical and electron microscopy, have been used for morphological observation of tissue sections. Optical microscopy (OM) allows for fast-acquisition high-throughput imaging, at the expense of diffraction-limited resolution ... -
The Cretaceous development of the Nordkapp Basin based on seismic interpretation
(Master thesis; Mastergradsoppgave, 2018-05-31)This thesis is focused on studying the development of the Nordkapp Basin during the Cretaceous Period. The basin is fault-controlled and is strongly influenced by salt tectonics. The basin is divided into two parts, which differs both in the average width and direction of their elongation. Moreover, the salt structures in the northeast and southwest parts of the basin also follow the trends in width ... -
Estimering av egenskaper til naturlige klasser i radarbilder med en blandingsmodell
(Master thesis; Mastergradsoppgave, 2018-05-31)I løpet av de siste årene har isdekket i polhavet gått fra å være flerårsis til å bli en sesongbasert istype. Hvordan isen utvikler seg på sommeren vil avhenge av smeltevannandelen, blant annet på grunn av at smeltevannet har mindre albedo enn isen. For å estimere andelen smeltevann er det i denne oppgaven utviklet flere metoder som kan brukes på satellittbilder. Disse metodene bruker en statistisk ...
