Fakultet for naturvitenskap og teknologi: Nye registreringer
Viser treff 1581-1600 av 5304
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MIS 3 age of the Veiki moraine in N Sweden – Dating the landform record of an intermediate-sized ice sheet in Scandinavia
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-14)The Veiki moraine in northern Sweden, a geomorphologically distinct landscape of ice-walled lake plains, has been interpreted to represent the former margin of an intermediate-sized pre–Last Glacial Maximum (LGM) Fennoscandian ice sheet, but its age is debated as either marine isotope stage (MIS) 5c or MIS 3. We have applied optically stimulated luminescence (OSL) and radiocarbon dating to four sites ... -
Physics-Guided Loss Functions Improve Deep Learning Performance in Inverse Scattering
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-15)Solving electromagnetic inverse scattering problems (ISPs) is challenging due to the intrinsic nonlinearity, ill-posedness, and expensive computational cost. Recently, deep neural network (DNN) techniques have been successfully applied on ISPs and shown potential of superior imaging over conventional methods. In this paper, we discuss techniques for effective incorporation of important physical ... -
ICEBEAR-3D: A Low Elevation Imaging Radar Using a Non-Uniform Coplanar Receiver Array for E Region Observations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-19)The Ionospheric Continuous-wave E region Bistatic Experimental Auroral Radar (ICEBEAR) has been reconfigured using a phase error minimization and stochastic antenna location perturbation technique. The resulting 45-baseline sparse non-uniform coplanar T-shaped array, ICEBEAR-3D, is used for aperture synthesis radar imaging of low elevation targets. The reconfigured receiver antenna array now has ... -
Critical Assessment of Metagenome Interpretation: the second round of challenges
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-08)Evaluating metagenomic software is key for optimizing metagenome interpretation and focus of the Initiative for the Critical Assessment of Metagenome Interpretation (CAMI). The CAMI II challenge engaged the community to assess methods on realistic and complex datasets with long- and short-read sequences, created computationally from around 1,700 new and known genomes, as well as 600 new plasmids ... -
Inference Guided Few-Shot Segmentation
(Master thesis; Mastergradsoppgave, 2022-06-22)Few-shot segmentation has in recent years gotten a lot of attention. The reason is its ability to segment images from classes based on only a handful of labeled support images. This opens up many possibilities when the need for a big dataset is removed. To do this a few-shot segmentation network need to extract as much quality information from each support image as possible. In this thesis we ... -
Rossby Wave Changes During the Recent Decades in Mid-Latitude Continents in the Northern Hemisphere
(Master thesis; Mastergradsoppgave, 2022-06-22)Increasing frequency and severity of extreme weather events throughout the recent years is a highly concerning topic. Extreme and unusual weather conditions, such as heat waves, floods and cold spells are causing a major concern for humanity. Agricultural changes, damages in infrastructure and the loss of human lives are some of the extreme weather event consequences, with the most drastic consequences ... -
Combined X-Ray Computed Tomography and X-Ray Fluorescence Drill Core Scanning for 3-D Rock and Ore Characterization: Implications for the Lovisa Stratiform Zn-Pb Deposit and Its Structural Setting, Bergslagen, Sweden
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-29)We present the results of a pilot study that integrates automated drill core scanning technology based on simultaneous X-ray computed tomography (XCT) and X-ray fluorescence (XRF) analyses to provide high-spatialresolution (<0.2 mm) information on 3-D rock textures and structures, chemical composition, and density. Testing of its applicability for mineral exploration and research was performed by ... -
Finite element simulation of transmission and reflection of acoustic waves in the ultrasonic transducer
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-30)In scanning acoustic microscopy (SAM), the image quality depends on several factors such as noise level, resolution, and interaction of the waves with sample boundaries. The theoretical equations for the reflection coefficient and transmission coefficient are suitable for plane boundaries but fail for curved/rough boundaries. We presented a finite element method-based modeling for the loss ... -
Plasma-neutral gas interactions in various space environments: Assessment beyond simplified approximations as a Voyage 2050 theme
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-26)In the White Paper, submitted in response to the European Space Agency (ESA) Voyage 2050 Call, we present the importance of advancing our knowledge of plasma-neutral gas interactions, and of deepening our understanding of the partially ionized environments that are ubiquitous in the upper atmospheres of planets and moons, and elsewhere in space. In future space missions, the above task ... -
Network Analysis and Boosting the Distribution to Local Consumers at Northern Senja, Norway with Potential Renewable Generation using Power Flow Control
(Master thesis; Mastergradsoppgave, 2022-06-08)Renewable generation and power flow control are increasing its importance for power systems. The promising development in the technology increases the efficiency for transferring energy. With increasing consumption, remote locations benefit from close laying power production due to reduced transfer losses. In these recent years, energy storage system and local renewable energy production injected ... -
Solar Photovoltaic Potential on Commercial Buildings in Arctic Latitudes
(Master thesis; Mastergradsoppgave, 2022-06-01)This thesis desires to study the use of solar resources in a less frequently used location, by exploring the use of a photovoltaic systems on the roof of a warehouse in Tromsø, Norway. The research is gathered using a 15 000 𝑚2 warehouse as the location, which has an annual energy consumption of 2,9 GWh. The solar resources at this location are highly dependent on season, with periods of polar ... -
Assessment of Solar Photovoltaics and Wind Energy for Increased Electrification and Grid Independent Farming
(Master thesis; Mastergradsoppgave, 2022-05-31)A solution towards increased electrification and reduced greenhouse gas emissions in the agriculture is local renewable energy production. Not only is it a sustainable and environmentally positive project, but with remarkably increasing electricity prices renewable energy projects can also be economically favorable for farmers, by reducing grid dependence and hence high electricity costs. In this ... -
DC-Approximated Power System Reliability Predictions with Graph Convolutional Neural Networks
(Master thesis; Mastergradsoppgave, 2022-05-30)The current standard operational strategy within electrical power systems is done following deterministic reliability practices. These practices are deemed to be secure under most operating situations when considering power system security, but as the deterministic practices do not consider the probability and consequences of operation, the operating situation may often become either too strict or ... -
Generating customer's credit behavior with deep generative models
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-17)Banks collect data x<sub>1</sub> in loan applications to decide whether to grant credit and accepted applications generate new data x<sub>2</sub> throughout the loan period. Hence, banks have two measurement-modalities, which provide a complete picture about customers. If we can generate x<sub>2</sub> conditioned on x<sub>1</sub> keeping the relationship between these two modalities, credit and ... -
Anomaly detection-inspired few-shot medical image segmentation through self-supervision with supervoxels
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-11)Recent work has shown that label-efficient few-shot learning through self-supervision can achieve promising medical image segmentation results. However, few-shot segmentation models typically rely on prototype representations of the semantic classes, resulting in a loss of local information that can degrade performance. This is particularly problematic for the typically large and highly heterogeneous ... -
Klimasatsing i kystfiskehavner: En analyse av energibruk på fangst- og mottaksleddet i kystfiskeflåten
(Research report; Forskningsrapport, 2022-03-01)Analyse av energibruk i fangst- og mottaksleddet viser at drivstofforbruk i flåteleddet representerer den største andelen av totalt energibruk for produksjon av ferskfisk, tørrfisk og frossenfisk. Vi finner at fartøy under 15 meter i gjennomsnitt driver mest drivstoffeffektivt fiske, sammenlignet med den øvrige kystfiskeflåten i Flakstad kommune. Vi estimerer at flåtens CO2-utslipp er økende fra ... -
Dataset of fitness trackers and smartwatches to measuring physical activity in research
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-16)Objectives: Accelerometer-based wrist-worn ftness trackers and smartwatches (wearables) appeared on the consumer market in 2011. Many wearable devices have been released since. The objective of this data paper is to describe a dataset of 423 wearables released before July 2017.<p> <p>Data description: We identifed wearables and extracted information from six online and ofine databases. We ... -
Tectonic evolution of the Indio Hills segment of the San Andreas fault in southern California, southwestern USA
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-01)Transpressional uplift domains of inverted Pliocene–Pleistocene basin fill along the San Andreas fault zone in Coachella Valley, southern California (USA), are characterized by fault linkage and segmentation and deformation partitioning. The Indio Hills wedge-shaped uplift block is located in between two boundary fault strands, the Indio Hills fault to the northeast and the main San Andreas fault ... -
Ammonium and Sulfate Assimilation Is Widespread in Benthic Foraminifera
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-20)Nitrogen and sulfur are key elements in the biogeochemical cycles of marine ecosystems to which benthic foraminifera contribute significantly. Yet, cell-specific assimilation of ammonium, nitrate and sulfate by these protists is poorly characterized and understood across their wide range of species-specific trophic strategies. For example, detailed knowledge about ammonium and sulfate assimilation ... -
Marine natural product inspired synthesis towards new antimicrobial and antifouling agents
(Doctoral thesis; Doktorgradsavhandling, 2022-08-30)Natural products (NPs) have been the major source for the development of new small molecule drugs in modern medicine. Despite NPs being so prominent, marine natural products (MNPs) and derivatives thereof are hardly found in clinically approved agents. Therefore, using bioactive MNPs as structural guidance for drug development is a largely untapped source. The focus of the presented thesis is on ...