Viser treff 61-80 av 294

    • Neoproterozoic orogenesis in south-eastern South America - An examination of pre-orogenic rifting, sedimentation, and mountain building processes recorded in the Dom Feliciano Belt 

      Percival, Jack James (Doctoral thesis; Doktorgradsavhandling, 2022-01-25)
      The Dom Feliciano Belt records the convergence between multiple South American and African cratonic bodies during the Neoproterozoic, and forms part of the larger South Atlantic Neoproterozoic Orogenic System (SANOS). Studying the evolution of the Dom Feliciano Belt allows the development of tectonic models spanning the time from pre-orogenic rifting to orogenesis, and the information recorded in ...
    • Machine Learning-based Classification, Detection, and Segmentation of Medical Images 

      Jha, Debesh (Doctoral thesis; Doktorgradsavhandling, 2022-01-21)
      Gastrointestinal tract (GI) cancers are among the most common types of cancers worldwide. In particular, colorectal cancer (CRC) is the most lethal in terms of number of incidences and mortality (third most common cause of cancer and the second common cause of cancer-related deaths). Colonoscopy is the gold standard for screening patients for CRC. During the colonoscopy, gastroenterologists examine ...
    • Arctic planktonic calcifiers in a changing ocean - A study on recent planktonic foraminifera and shelled pteropods in the Fram Strait-Barents Sea region 

      Ofstad, Siri (Doctoral thesis; Doktorgradsavhandling, 2021-12-16)
      The Arctic marine realm is being transformed due to the anthropogenically-induced climate change. In the Arctic, the effects of climate change are intensified due to polar amplification and have led to processes in the ocean such as sea-ice retreat, ocean acidification and the increased presence of boreal species referred to as ‘Atlantification’. This thesis presents rare investigations of marine ...
    • Developing the MAR databases – Augmenting Genomic Versatility of Sequenced Marine Microbiota 

      Klemetsen, Terje (Doctoral thesis; Doktorgradsavhandling, 2021-12-10)
      This thesis introduces the MAR databases as marine-specific resources in the genomic landscape. Paper 1 describes the curation effort and development leading to the MAR databases being created. It results in the highly valued reference database MarRef, the broader MarDB, and the marine gene catalog MarCat. Definition of a marine environment, the curation process, and the Marine Metagenomics Portal ...
    • Advancing Land Cover Mapping in Remote Sensing with Deep Learning 

      Liu, Qinghui (Doctoral thesis; Doktorgradsavhandling, 2021-12-08)
      Automatic mapping of land cover in remote sensing data plays an increasingly significant role in several earth observation (EO) applications, such as sustainable development, autonomous agriculture, and urban planning. Due to the complexity of the real ground surface and environment, accurate classification of land cover types is facing many challenges. This thesis provides novel deep learning-based ...
    • Radio wave propagation through the ionosphere 

      Rexer, Theresa (Doctoral thesis; Doktorgradsavhandling, 2021-11-24)
      The non-transient plasma that is closest to Earth is found in the ionosphere at altitudes above approximately 60 km. It is observed either by ground-based, in-situ, or space-borne instrumentation and utilized to study and determine plasma phenomena and dynamics and the near-Earth space. Through active modification experiments, transmitting high-power, high-frequency radio waves into the ionospheric ...
    • Assessing the relationship between living benthic foraminifera and methane emission in the Arctic Ocean 

      Melaniuk, Katarzyna (Doctoral thesis; Doktorgradsavhandling, 2021-11-04)
      Methane is a powerful greenhouse gas. In marine environments, it is buried deep in the sediments in the form of gas hydrate, an ice-like structure. Due to its form, gas hydrate is sensitive to changes in temperature and pressure. Because of that, the ongoing climate change can trigger destabilization of its sub-seabed deposits. This may result in a release of great amounts of methane into the ...
    • Auroral Image Processing Techniques - Machine Learning Classification and Multi-Viewpoint Analysis 

      Kvammen, Andreas (Doctoral thesis; Doktorgradsavhandling, 2021-09-30)
      Every year, millions of scientific images are acquired in order to study the auroral phenomena. The accumulated data contain a vast amount of untapped information that can be used in auroral science. Yet, auroral research has traditionally been focused on case studies, where one or a few auroral events have been investigated and explained in detail. Consequently, theories have often been developed ...
    • Nonlinear optics 

      Juhász, Dávid (Doctoral thesis; Doktorgradsavhandling, 2021-09-24)
      Nonlinear light-matter interactions have been drawing attention of physicists since the 1960's. Quantum mechanics played a significant role in their description and helped to derive important formulas showing the dependence on the intensity of the electromagnetic field. High intensity light is able to generate second and third harmonics which translates to generation of electromagnetic field with ...
    • Millennial-scale variability of Atlantic water inflow in the northern Nordic Seas and the northwestern Barents Sea - Relationship to abrupt climate oscillations, cryosphere and methane seepage from the seafloor 

      El Bani Altuna, Naima (Doctoral thesis; Doktorgradsavhandling, 2021-09-17)
      Climate change affects the Arctic to a greater extent than the global average, causing rapid sea-ice loss and changes in the inflow of warm Atlantic water in the Arctic. Arctic sediments host vast amounts of greenhouse gases in the form of gas hydrates (ice-like cages that trap gas within), that can be released to the seafloor if temperature increases and/or pressure decreases. Climate projections ...
    • Ground Dynamics in the Norwegian Periglacial Environment Investigated by Synthetic Aperture Radar Interferometry 

      Rouyet, Line (Doctoral thesis; Doktorgradsavhandling, 2021-09-10)
      Cold polar and mountainous periglacial environments are characterised by highly dynamic ground surfaces that move under the action of frost and gravity, and contribute to shaping the landscape. The movement rates and directions are spatially and temporally variable, depending on the involved periglacial processes and their environmental controlling factors. Spaceborne Synthetic Aperture Radar (SAR) ...
    • On the Evolvability of OXA-48. A comprehensive study of new functions within the β-lactamase OXA-48 

      Fröhlich, Christopher (Doctoral thesis; Doktorgradsavhandling, 2021-08-27)
      Our understanding of how antimicrobial resistance enzymes evolve to expand their substrate spectrum is limited. OXA-48, an enzyme able to catalyse the hydrolysis of β-lactam drugs, has become one of the most successfully disseminating β-lactamases. Although OXA-48 hydrolyses penicillins with high efficiency, its activity towards oxyimino cephalosporins, such as ceftazidime, is limited. Thus, ceftazidime ...
    • Leveraging Computer Vision for Applications in Biomedicine and Geoscience 

      Johansen, Thomas Haugland (Doctoral thesis; Doktorgradsavhandling, 2021-06-25)
      Skin cancer is one of the most common types of cancer and is usually classified as either non-melanoma and melanoma skin cancer. Melanoma skin cancer accounts for about half of all skin cancer-related deaths. The 5-year survival rate is 99% when the cancer is detected early but drops to 25% once it becomes metastatic. In other words, the key to preventing death is early detection. Foraminifera ...
    • Optical Waveguides for Infrared Spectroscopic Detection of Molecular Gases 

      Vlk, Marek (Doctoral thesis; Doktorgradsavhandling, 2021-06-18)
      Fields like medical diagnostics, urban and industrial environmental monitoring or basic microbiological research greatly benefit from advances in chemical and biological sensing. These applications require rapid sample analysis, reduced needs for sample handling, or good sensor network. Such demands can be met with miniaturised sensors utilising methods which secure sufficient sensitivity and ...
    • Collapse of a marine-based ice sheet 

      Esteves, Mariana da Silveira Ramos (Doctoral thesis; Doktorgradsavhandling, 2018-08-16)
      The Barents Sea Ice Sheet (BSIS) is a good palaeo-analogue to the West Antarctic Ice Sheet (WAIS), and understanding the key processes occurring during the deglaciation of the BSIS can yield important insights into the drivers and response of marine-based ice sheets to climatic changes. This is important since marine-based ice sheets, such as the BSIS and WAIS, are particularly vulnerable to oceanic ...
    • Numerical simulations and stochastic modeling of intermittent fluctuations in magnetized plasmas 

      Decristoforo, Gregor (Doctoral thesis; Doktorgradsavhandling, 2021-05-21)
      The exhaust of particles and heat in the boundary of contemporary magnetic confinement experiments remains to this day a major obstacle on the road to commercially viable fusion energy production. It is recognized, that coherent structures of hot and dense plasma, called blobs or filaments, are the dominant mechanism for cross-field particle transport. These filaments are created by plasma turbulence ...
    • EDMON - Electronic Disease Surveillance and Monitoring Network: A Personalized Health Model-based Digital Infectious Disease Detection Mechanism using Self-Recorded Data from People with Type 1 Diabetes 

      Woldaregay, Ashenafi Zebene (Doctoral thesis; Doktorgradsavhandling, 2021-05-28)
      Through time, we as a society have been tested with infectious disease outbreaks of different magnitude, which often pose major public health challenges. To mitigate the challenges, research endeavors have been focused on early detection mechanisms through identifying potential data sources, mode of data collection and transmission, case and outbreak detection methods. Driven by the ubiquitous nature ...
    • Radar System Development for Drone Borne Applications with Focus on Snowpack Parameters 

      Jenssen, Rolf-Ole Rydeng (Doctoral thesis; Doktorgradsavhandling, 2021-05-11)
      A complete representation of the Arctic cryosphere has historically been restricted by its remoteness, large extent, and restrictions in measurement methods and equipment. Here, remote sensing of snow-cover is a central method to improve the current knowledge of the Earth's ecosystem, and hence a critical component in cryospheric models. The use of drone-borne radar systems has seen considerable ...
    • Machine Learning for Enhanced Maritime Situation Awareness: Leveraging Historical AIS Data for Ship Trajectory Prediction 

      Murray, Brian (Doctoral thesis; Doktorgradsavhandling, 2021-05-03)
      In this thesis, methods to support high level situation awareness in ship navigators through appropriate automation are investigated. Situation awareness relates to the perception of the environment (level 1), comprehension of the situation (level 2), and projection of future dynamics (level 3). Ship navigators likely conduct mental simulations of future ship traffic (level 3 projections), that ...