Now showing items 221-240 of 322

    • Maritime Target Detection in Non-homogeneous Sea Clutter Environments based on Single- and Multi-polarization Synthetic Aperture Radar Data 

      Tao, Ding (Doctoral thesis; Doktorgradsavhandling, 2015-12-03)
      This thesis discusses the subject of maritime target detection based on single- and multi-polarization synthetic aperture radar (SAR) data. The primary objective is to develop an automatic and effective target detection algorithm, which is able to provide robust performance for an operational maritime surveillance system under various circumstances. There are two frequently encountered major ...
    • Waveguide Mach-Zehnder interferometer for measurement of methane dissolved in water 

      Lindecrantz, Susan M. (Doctoral thesis; Doktorgradsavhandling, 2016-04-25)
      In this dissertation, we present the development of a novel, compact and highly sensitive waveguide Mach-Zehnder interferometer to measure methane dissolved in water. Methane is a greenhouse gas, like carbon dioxide, and is emitted from both natural sources and human activities. Due to the challenges to measure dissolved methane in the sea and the vast area it covers, much of the methane cycle is ...
    • Effects of Geomagnetic Disturbances on Offshore Magnetic Directional Wellbore Positioning in the Northern Auroral Zone 

      Edvardsen, Inge (Doctoral thesis; Doktorgradsavhandling, 2016-01-29)
      This thesis focuses on how disturbances in the geomagnetic field, offshore northern Norway, may affect the accuracy of magnetic directional wellbore surveying. The topics discussed are, however, applicable to the entire northern auroral zone. Suggestions on how to manage the effect of increased geomagnetic activity on magnetic directional wellbore survey operations in and near the auroral zone are ...
    • Web-Based Surgical Telementoring. Service design and evaluation of the key features. 

      Budrionis, Andrius (Doctoral thesis; Doktorgradsavhandling, 2015-10-13)
      This thesis provides a detailed outlook on research in telementoring, identifying the fundamental limitations hindering its smooth integration into clinical practice. The findings are based on literature reviews and user involvement, minimizing the gap between research and actual use of the system. To address the identified shortcomings, a service-oriented approach to clinical VC systems was proposed. ...
    • Insights into bacterial protection and survival. A study of three enzymes from cold-adapted bacteria 

      Grgic, Miriam (Doctoral thesis; Doktorgradsavhandling, 2015-10-02)
      Bacteria are the most abundant organisms and can be found in different habitats, from polar regions, deserts and volcanoes, deep ocean trenches to the upper atmosphere. In all these environments, they are exposed to various chemical hazards, such as antibacterial chemicals (antibiotics) produced by other organisms that are found in the same habitat. In addition, they are exposed to threats from ...
    • Late Quaternary paleoceanography of the northern continental margin of Svalbard 

      Chauhan, Teena (Doctoral thesis; Doktorgradsavhandling, 2015-08-27)
      This study focuses on the reconstruction of the variability of Atlantic Water inflow to the Arctic Ocean and its influence on the Svalbard-Barents Sea Ice Sheet (SBIS), sea-ice cover, variations in the bottom current strength and the depositional environment in the past. For this reconstruction, the distribution patterns of planktic and benthic foraminiferal assemblages, oxygen and carbon stable ...
    • Role of subsea permafrost and gas hydrate in postglacial Arctic methane releases 

      Portnov, Aleksei D (Doctoral thesis; Doktorgradsavhandling, 2015-09-18)
      Greenhouse gas methane is contained as gas hydrate, an icy structure, under the seabed in enormous amounts of Arctic regions. West Svalbard continental margin, which we investigated here, is one of these regions. Also, in the Russian Kara Sea the subsea permafrost is acting as a cap for the gas to be released in the future. But continuous expulsions of methane have been already observed in both ...
    • Some combinatorial invariants determined by Betti numbers of Stanley-Reisner ideals 

      Roksvold, Jan Nyquist (Doctoral thesis; Doktorgradsavhandling, 2015-09-08)
      The thesis contains new results on the connection between the algebraic properties of certain ideals of a polynomial ring and properties of error-correcting linear codes, matroids and simplicial complexes. We demonstrate that the graded Betti numbers of the facet ideal of a matroid are determined by the Betti numbers of the blocks of the matroid. The extended weight enumerator of coding theory is ...
    • Protein Dynamics Regulates Enzyme Enthalpy-Entropy Balance 

      Isaksen, Geir Villy (Doctoral thesis; Doktorgradsavhandling, 2015-06-26)
      Accurate predictions of free energies and the corresponding enthalpies and entropies from computer simulations are invaluable for understanding enzymatic catalysis and drug actions in terms of actual structure activity relationships. To facilitate the management and handling of the enormous amount of data generated when calculating thermodynamic parameters, we have developed a high-throughput interface ...
    • DNA metabolism in extremophiles Structure-function studies of proteins involved in DNA repair and replication from Aliivibrio salmonicida and Deinococcus radiodurans 

      Lian, Kjersti (Doctoral thesis; Doktorgradsavhandling, 2015-06-16)
      Deinococcus radiodurans is a gram-positive bacterium with a pink-orange colour first isolated in canned meat. The bacteria is remarkable amongst all species studied to date by its unusual ability to repair hundreds of radiation induced DNA double strand breaks where normal species can only repair a dozen. Our studies of the DNA polymerase III β-subunit (β-clamp) and Exonuclease III from D. radiodurans ...
    • Ice rafting, Ocean circulation and Glacial activity on the western Svalbard margin 0–74 000 years BP 

      Jessen, Simon Pind (Doctoral thesis; Doktorgradsavhandling, 2015-03-27)
      The thesis builds on 11 sediment cores from c. 600 to 1900 m water depth from the continental slope west of Svalbard and one core from the Barents Sea shelf. Together, the cores cover the last 74,000 years. The primary goal was to gain a better insight in ocean circulation and glacial activity in a climatic context on glacial-interglacial and millennial time scales. The main parameters studied are ...
    • On the Generalized Curvature Ocean Surface Scattering Model for the NRCS and Doppler Frequency and its application to ocean surface wind retrieval from Synthetic Aperture Radar data 

      Said, Faozi (Doctoral thesis; Doktorgradsavhandling, 2015-01-23)
      Ocean wind monitoring is an integral part of weather forecasting, maritime shipping lane planning, offshore wind research, as well as the study of climate patterns. Satellite radar instruments, such as Synthetic Aperture Radars (SAR), can help achieve this important task by monitoring the wind conditions over the sea surface. Using specially developed functions, called geophysical model functions, ...
    • Practical synthetic methods for three unstable, unsaturated bromomethyl ketones, and on the use of near-orthogonal experiments for synthetic exploration. 

      Descomps, Alexandre Pierre (Doctoral thesis; Doktorgradsavhandling, 2015-06-18)
      The thesis consists of two different parts: The organic part presents the development of a convenient procedure for the synthesis of three rare, unstable α,β-unsaturated brominated methyl ketones from common commercially available regents. This family of molecule has been very challenging to synthesize and a short history about these efforts as well as different general strategies to produce them ...
    • Structural development and metallogenesis of Paleoproterozoic volcano-sedimentary rocks of the Rombak Tectonic Window 

      Angvik, Tine Larsen (Doctoral thesis; Doktorgradsavhandling, 2014-10-30)
      The Rombaken Tectonic Window (RTW) is a basement culminations within the Caledonian thrust nappes in northern Norway. It appear as an inlier of Paleoproterozoic supracrustal rocks on Paleoproterozoic basement rocks. The RTW consist of several metasedimentary and metavolcanic N-S striking belts enclosed within large granitic bodies. The RTW marks the boundary between Archean basement rocks to the ...
    • HealthTrust: trust-based retrieval of health social media videos 

      Fernandez-Luque, Luis (Doctoral thesis; Doktorgradsavhandling, 2014-10-24)
      There is a global trend towards the use of the Internet to search for information about health issues. We have access to a wide range of online health information; especially the so-called social media (e.g. blogs, videos). However, finding good quality resources is not easy in the current context of information overload. Today, very relevant and valuable health social media has to compete in ...
    • Dynamics and statistical properties of blob structures in scrape-off layer plasmas 

      Kube, Ralph (Doctoral thesis; Doktorgradsavhandling, 2014-12-16)
      The velocity scaling of blobs, subject to dissipation by either electric currents to the sheaths, or dynamical friction, is studied by numerical simulations where the blob amplitude relative to the background plasma is a free parameter. When subject to dissipation by sheath currents, the radial velocity of a blob depends on the square of its cross field size l, vrad ∼ √l for small l. For large l, ...
    • Post-Caledonian brittle faults along the SW Barents Sea Margin: onshore-offshore margin architecture and fault rock-forming conditions 

      Indrevær, Kjetil (Doctoral thesis; Doktorgradsavhandling, 2014-11-13)
      The thesis aims to unravel the evolution and finite stage architecture of the SW Barents Sea Margin, which formed as a part of the rifting of present day Greenland and Scandinavia and the opening of the North Atlantic Ocean (cf. Faleide et al., 2008). The SW Barents Sea Margin studied in this thesis starts just north of the Lofoten-Vesterålen archipelago, continues northward outboard northern ...
    • 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 ...
    • Characterization of Low Backscatter Regions in the Marine Environment by Multipolarization C- and X-band Synthetic Aperture Radar Data 

      Skrunes, Stine (Doctoral thesis; Doktorgradsavhandling, 2014-10-10)
      The focus of this thesis is the application of multipolarization SAR data for characterization of marine oil spills and other low backscatter ocean phenomena. A variety of SAR descriptors are investigated for the purpose of discriminating between oil spills and look-alikes. The effects of various parameters on the imaging, including sensor frequency, imaging geometry and oil properties, are addressed. ...
    • A multi-proxy approach for reconstructing oceanographic dynamics during the Holocene Development and Application of benthic foraminifera as proxies in the Polar North Atlantic 

      Skirbekk, Kari (Doctoral thesis; Doktorgradsavhandling, 2014-10-23)
      Two sediment cores and several sediment surface samples have been retrieved in order to develop and apply benthic foraminifera as proxies in the Polar North Atlantic. The purpose of the surface samples was to develop the Mg/Ca method for cold water environments, as this has been proven a valuable paleo-thermometer for several marine environments. This was done for three species of Benthic foraminifera: ...