Viser treff 105-124 av 290

    • Ice in Norwegian subarctic fjords and coastal regions: An examination of ice formation, properties, and trends based on remote sensing and in situ data 

      O'Sadnick, Megan (Doctoral thesis; Doktorgradsavhandling, 2022-09-16)
      Larger fjords along the Norwegian coast are ice free all year due to the influence of warm Atlantic water, however, sea ice can form in the inner parts of fjords and in smaller fjord branches. While a wide breadth of work exists examining mainland Norwegian fjords often focused on water mass dynamics and their link to biological processes, little research has been conducted on specifically sea ice ...
    • 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 ...
    • Ice Shelf - Ocean Interaction in the Eastern Weddell Sea, Antarctica 

      Hattermann, Tore (Doctoral thesis; Doktorgradsavhandling, 2012-12-10)
      This thesis investigates the interaction of the Antarctic ice shelves along the coast of Dronning Maud Land with the ocean circulation in the Eastern Weddell Sea. A set of direct oceanic observations below the Fimbul Ice Shelf, which were acquired during three Antarctic field seasons in the austral summers 2009/10, 2010/11 and 2011/12, is a central element of the presented work. This new oceanographic ...
    • Improving Latency in Mobile/Cloud Applications 

      Pettersen, Robert Molund (Doctoral thesis; Doktorgradsavhandling, 2016-08-25)
      Smartphones are becoming comparable to desktop computers in terms of computational power, and offer diverse applications ranging from social media and gaming, to multimedia and banking. A particular class of mobile applications, mobile/cloud applications, are tightly coupled with the cloud. While executing on the mobile device, they communicate frequently with the cloud for crucial functionality. Use ...
    • Improving Representation Learning for Deep Clustering and Few-shot Learning 

      Trosten, Daniel Johansen (Doctoral thesis; Doktorgradsavhandling, 2023-08-23)
      <p>The amounts of data in the world have increased dramatically in recent years, and it is quickly becoming infeasible for humans to label all these data. It is therefore crucial that modern machine learning systems can operate with few or no labels. The introduction of deep learning and deep neural networks has led to impressive advancements in several areas of machine learning. These advancements ...
    • In-situ Measurements of Mesospheric Aerosols - On the observable characteristics of nanoscale ice and meteoric smoke particles 

      Antonsen, Tarjei (Doctoral thesis; Doktorgradsavhandling, 2019-01-24)
      Two sounding rocket payloads were launched from Andøya Space Centre (69.29 N, 16.02 E) during the summer of 2016 within the MAXIDUSTY campaign. Their payloads contained instrumentation aimed at investigating the characteristics of nanoscale aerosols in the upper summer mesosphere, and the role of these particles in phenomena like noctilucent clouds and polar mesospheric summer echoes (PMSE). The ...
    • 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 ...
    • An Integrated Data Analytics Framework for Enhancing the Environmental and Life-cycle Economic Performance in Shipping 

      Bui, Khanh Quang (Doctoral thesis; Doktorgradsavhandling, 2023-03-03)
      <p>Shipping has been recognized as the most efficient mode of transport, carrying over 80% of international trade volume. The shipping industry is at the beginning of one of its greatest energy and technology transition driven by decarbonization drivers in terms of stringent emission regulations and commercial pressure. Digitalization can enable the transition by leveraging Machine Learning (ML) and ...
    • Interactive Visualization on High-Resolution Tiled Display Walls with Network Accessible Compute- and Display-Resources 

      Hagen, Tor-Magne Stien (Doctoral thesis; Doktorgradsavhandling, 2011-09-26)
      The vast volume of scientific data produced today requires tools that can enable scientists to explore large amounts of data to extract meaningful information. One such tool is interactive visualization. The amount of data that can be simultaneously visualized on a computer display is proportional to the display’s resolution. While computer systems in general have seen a remarkable increase in ...
    • Interfacial solvation modelling with PCM 

      Mozgawa, Krzysztof (Doctoral thesis; Doktorgradsavhandling, 2016-02-17)
      The effect of surfaces and interfaces on the molecular properties and structure is of a great interest in the applied sciences and technology. In the following thesis, a theoretical framework for the calculations of the free energy and properties, including the effect of interfaces and surfaces, in quantum-mechanical formalism is presented. The model of choice is Polarizable Continuum Method (PCM), ...
    • Interferometric and high time-resolution observations of naturally enhanced ion-acoustic echoes at the EISCAT Svalbard radar: Software radar and incoherent scattering 

      Grydeland, Tom (Doctoral thesis; Doktorgradsavhandling, 2003-06-24)
      We know that the visible Aurora Borealis is structured on many different scales, down to a few tens of metres. By using the EISCAT radars on Svalbard as an interferometer, we have found structures in the radio echoes from the auroral ionosphere on a scale approaching that of the visible aurora, and simultaneously with it, but at far greater ranges. In this thesis we discuss how these radar observations ...
    • Intermittent fluctuations in the boundary of magnetically confined fusion plasmas 

      Ahmed, Sajidah (Doctoral thesis; Doktorgradsavhandling, 2023-10-09)
      Fluctuation-induced transport in the form of hot and dense blob-like filaments is a profound concern for the successful operation of commercially-viable fusion reactors. These turbulent phenomena are inherent in the scrape-off layer (SOL), a region of magnetic field lines intersecting with the material surfaces. These filaments propagate radially outward leading to damaging plasma-wall interaction ...
    • Investigation of Sea Ice Using Multiple Synthetic Aperture Radar Acquisitions 

      Yitayew, Temesgen Gebrie (Doctoral thesis; Doktorgradsavhandling, 2018-02-23)
      The thesis investigates imaging in the vertical direction of different types of ice in the arctic using synthetic aperture radar (SAR) tomography and SAR interferometry. In the first part, the magnitude and the positions of the dominant scattering contributions within snow covered fjord and lake ice layers are effectively identified by using a very high resolution ground-based tomographic SAR system. ...
    • Investigations of summer sea ice with X and C-band multi-polarimetric synthetic aperture radar (SAR) 

      Fors, Ane Schwenke (Doctoral thesis; Doktorgradsavhandling, 2017-03-17)
      In this thesis, we explore the possibilities and limitations of using space-borne multi-polarimetric SAR in summer sea ice investigations. Both X and C-band data are examined. The study utilizes two data sets collected in the Arctic in 2011 (Fram Strait) and 2012 (north of Spitsbergen). Both sets combine satellite SAR scenes with co-located ground and air-borne measurements. Firstly, the study ...
    • Iron dependent gene regulation and siderophore systems in Vibrionaceae 

      Thode, Sunniva Katharina (Doctoral thesis; Doktorgradsavhandling, 2017-03-15)
      Bacteria live in fluctuating environments, which they sense and respond to through gene regulation. Availably of iron is an example of an element fluctuating and that can Bacteria sense.Iron is an essential micronutrient that is scares in several environments, especially in a host. The ferric uptake regulator, Fur, is the major iron level sensing protein and regulator of iron acquisition systems in ...
    • KAIRA - The Kilpisjärvi Atmospheric Imaging Receiver Array 

      McKay, Derek (Doctoral thesis; Doktorgradsavhandling, 2018-08-24)
      The Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) is a phased-array radio detector located in Arctic Finland, where auroral electron precipitation is common. This unique deployment of a modern radio telescope in an unconventional location has resulted in a novel and powerful instrument capable of carrying out a large variety of remote-sensing, geoscience experiments. This work presents a ...
    • Label-free super-resolution optical microscopy 

      Jayakumar, Nikhil (Doctoral thesis; Doktorgradsavhandling, 2024-02-06)
      To see structures well below 200 nm using visible light, super-resolution techniques have been developed. Most of these techniques rely on fluorescence labelling or use of artificial materials to go beyond the Abbe limit. Therefore, achieving super-resolution in the label-free regime is the problem that is being addressed in this thesis. In this work, high-index contrast dielectric waveguides are ...
    • Late glacial and deglacial paleoceanographic and environmental changes at Vestnesa Ridge, Fram Strait: challenges in reading methane-influenced sedimentary records 

      Sztybor, Kamila (Doctoral thesis; Doktorgradsavhandling, 2017-01-18)
      Denne avhandlingen er basert på fire sedimentkjerner fra et område ved Vest Svalbard hvor metan siver opp fra havbunnen. Studien fokuserer på å rekonstruere graden av metanutsiving i fortiden, samt klimavariasjoner i Arktiske strøk med bruk av bentiske foraminiferer. Foraminiferer er encellede organismer som produserer en kalkholdig skall som bevares i sedimentene på havbunnen. Ved å se på geokjemiske ...
    • Late Glacial – Holocene climate variability and sedimentary environments on northern continental shelves Zonal and meridional Atlantic Water advection 

      Sørensen, Steffen Aagaard (Doctoral thesis; Doktorgradsavhandling, 2011-03-22)
      The overall objective for this PhD-study was to further advance the understanding of the oceanographic variability and development in the Nordic Seas during the Late Glacial and the Holocene and towards the present. The focus is specifically on the poleward Atlantic Water advection along the continental margins of Norway, into the SW Barents Sea and along the West Spitsbergen slope. Four high ...
    • Late Pleistocene-Holocene history of Svalbard ice caps and glaciers – integrating marine, terrestrial and lacustrine archives 

      Allaart, Lis (Doctoral thesis; Doktorgradsavhandling, 2021-03-25)
      The Arctic regions are affected by the modern climate change to a greater extent than the global average. This effect is called the Arctic amplification and is reflected in air temperatures rising with double rate and increased precipitation compared to the global average. The climate of Svalbard is strongly related to variations in the atmospheric and oceanic circulation patterns, and the archipelago ...