Now showing items 1-20 of 246

    • 3D and 4D seismic investigations of fluid flow and gas hydrate systems 

      Waage, Malin (Doctoral thesis; Doktorgradsavhandling, 2019-02-18)
      Using the state-of-the-art high resolution P-Cable 3D seismic system, in this thesis we (1) study the shallow strata (<1km below seabed) and describe the geological controls and driving mechanisms for fluid leakage at two sites in the northern Barents Sea, and (2) introduce a new time-lapse seismic method for high-frequency (~30-350 Hz) P-Cable seismic data. The study areas are interesting as ...
    • Acyl homoserine lactone signaling in members of the Vibrionaceae family 

      Purohit, Amit (Doctoral thesis; Doktorgradsavhandling, 2013-06-13)
      Bacterial cell to cell communication, which involves regulation of gene expression in response to cell density, is defined as Quorum Sensing (QS). In QS small molecule signals are produced, which regulate their own production and are defined as auto-inducers. These signals are received by receiver proteins and in response certain genes are regulated directly or indirectly by these receiver proteins. ...
    • Advanced signal processing techniques with EISCAT3D 

      Stamm, Johann (Doctoral thesis; Doktorgradsavhandling, 2022-05-24)
      A new, modern ionospheric radar, called EISCAT3D, is under construction in northern Fennoscandia. In the first stage, the radar will have three sites, one combined transmit/receiver site shouth of Skibotn, and receiver sites in Kaaresuvanto and Kaiseniemi. The radar will consist of large groups of dipole antennas that are steered by shifting the phase of the transmitted or received signal. The beam ...
    • Advancing Deep Learning for Automatic Autonomous Vision-based Power Line Inspection 

      Nguyen, Van Nhan (Doctoral thesis; Doktorgradsavhandling, 2019-12-03)
      Electricity is fundamental to the ability to function of almost all modern-day societies. To maintain the reliability, availability, and sustainability of electricity supply, electric utilities are usually required to perform visual inspections on their electrical grids regularly. These inspections have been typically carried out using a combination of airborne surveys via low-flying helicopters and ...
    • 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 ...
    • Advancing relativistic electronic structure methods for solids and in the time domain 

      Kadek, Marius (Doctoral thesis; Doktorgradsavhandling, 2018-08-28)
      Effects arising from the special theory of relativity significantly influence the electronic structure and properties of molecules and solid-state materials containing heavy elements. At the same time, the inclusion of the relativistic effects in theoretical and computational models increases their methodological complexity and the computational cost. In the solid state, additional challenges ...
    • Advancing Segmentation and Unsupervised Learning Within the Field of Deep Learning 

      Kampffmeyer, Michael Christian (Doctoral thesis; Doktorgradsavhandling, 2018-10-19)
      Due to the large improvements that deep learning based models have brought to a variety of tasks, they have in recent years received large amounts of attention. However, these improvements are to a large extent achieved in supervised settings, where labels are available, and initially focused on traditional computer vision tasks such as visual object recognition. Specific application domains that ...
    • Advancing Unsupervised and Weakly Supervised Learning with Emphasis on Data-Driven Healthcare 

      Mikalsen, Karl Øyvind (Doctoral thesis; Doktorgradsavhandling, 2019-02-15)
      In healthcare, vast amounts of data are stored digitally in the electronic health records (EHRs). EHRs represent a largely untapped source of clinically relevant information, which combined with advances in machine learning, have the potential to transform healthcare into a more data-driven direction. However, due to the complexity and poor quality of the EHRs, data-driven healthcare is facing many ...
    • Along the path of bacterial nonulosonic acids. A study of the bio- and in vitro synthesis of sialic acid related compounds 

      Halsør, Marie-Josée Haglund (Doctoral thesis; Doktorgradsavhandling, 2019-10-25)
      Nonulosonic acids (NulOs) are sugars expressed on the surface of bacterial cells as well as vertebrates and are involved in a multitude of physiological and pathogenic processes. Their biosynthesis is directed by gene clusters that vary in both gene content and organization, leading to a diverse family of compounds. The exploration of this diversity is relatively recent, helped by the amount of ...
    • Analysis and Interpretation of C-band Polarimetric SAR signatures of Sea Ice 

      Moen, Mari-Ann (Doctoral thesis; Doktorgradsavhandling, 2015-01-16)
      Operational sea ice charts are currently produced manually, an inefficient process resulting in subjective ice charts. Hence, there is a need for automating this procedure. This thesis investigates how polarimetric microwave radar signatures relate to the physical properties of sea ice, and how these signatures may contribute to the development of robust automatic algorithms. Our analyses are based ...
    • Analysis of Oil Spill and Sea Ice Measurements Using Full-Polarimetric and Hybrid-Polarity Synthetic Aperture Radar data 

      Espeseth, Martine (Doctoral thesis; Doktorgradsavhandling, 2019-12-05)
      Synthetic Aperture Radar (SAR) data has been used for decades to detect oil slicks and monitoring sea ice. With increased oil and gas exploration in the Arctic follows higher risk for oil spills. Knowledge of the sea ice and oil spills is important for making clever and efficient decisions in a hectic and non-hectic operational situation. The potential and limitations of the hybrid-polarity (HP) SAR ...
    • Angles as tool for grasping space. Teaching of angles based on students’ experiences with physical activities and body movement 

      Fyhn, Anne Birgitte (Doctoral thesis; Doktorgradsavhandling, 2007-06-13)
      The thesis enlightens how the choice of context as well as the approach to mathematics is important in introducing the concepts of angles. The analyses indicate that students should not be introduced to measuring angles before they are able to sort out angles according to their sizes. Angles can be introduced by use of the students’ bodies in a climbing context, where the word angle refers to ...
    • Applications of Multiwavelets to Energies and Properties 

      Brakestad, Anders (Doctoral thesis; Doktorgradsavhandling, 2022-02-18)
      The goal of quantum chemistry is to provide fast and accurate algorithms for the computation of molecular energies and properties. Over the years, a large number of methods have become available, and today computational chemists have a very rich toolbox of protocols that can be used to gain insight to chemistry. Gaussian type orbital (GTO) basis sets are at the core of most modern algorithms, and ...
    • Applying Multivariate Analysis to Developing Electrodialytic Remediation of Harbour Sediments from Arctic Locations 

      Pedersen, Kristine Bondo (Doctoral thesis; Doktorgradsavhandling, 2015-03-13)
      Electrodialytic remediation (EDR) is a method for removing pollutants from different materials achieved by acidification and transport processes induced by application of an electric field of low intensity. In the thesis, EDR was shown to be a reliable technology for removal of heavy metals, PAH, PCB and TBT from harbour sediments. The final concentrations of heavy metals met the background criteria ...
    • Arctic Ocean warmings from the last glaciation to the present : implementing and assessing the reliability of planktic foraminiferal paleoreconstructions 

      Zamelczyk, Katarzyna Agnieszka (Doctoral thesis; Doktorgradsavhandling, 2012-05-11)
      The aim of the PhD study was to use planktic foraminifera to elucidate paleoceanographic variability and the preservation state of calcium carbonate in the eastern Fram Strait throughout the last 30,000 years. Sediment cores were studied using a multiproxy approach which included analyzing planktic and benthic foraminiferal fauna distribution patterns, measurements of stable isotopes (δ18O, δ13C), ...
    • 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 ...
    • 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 ...
    • Associations of pulmonary parameters with accelerometer data 

      Dias, André (Doctoral thesis; Doktorgradsavhandling, 2014-03-25)
      In Europe it is estimated that the number of elderly people aged above 65 will have doubled by 2060. In several chronic pulmonary diseases patients can suffer recurrent exacerbation episodes that can lead to severe breathing or death. In this thesis we explore the association of physical activity to lung health parameters, focusing on cystic fibrosis and chronic obstructive pulmonary disease ...
    • 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 ...
    • Automatic Inspection of Cod (Gadus Morhua L.) Fillets by Hyperspectral Imaging 

      Sivertsen, Agnar Holten (Doctoral thesis; Doktorgradsavhandling, 2011-11-11)
      The manual trimming and inspection of cod fillets by candling, is considered the bottleneck of cod fillet processing. The operation is both labour intensive and expensive, reported to account for as much as 50 % of the cost with cod fillet production. Due to the high labour costs in Norway, it is of great interest for the industry to optimize this process. In this work a hyperspectral imaging ...