Now showing items 2641-2660 of 5379

    • Two-axis tracking solar irradiance measurements at Tromsø 

      Hansen, Jakob Holden (Master thesis; Mastergradsoppgave, 2020-06-29)
      The world is changing towards using more renewable, rather than fossil energy sources in order to reach the 1.5 degrees celsius goal of the Paris agreement (Merchant, 2018). This thesis’ main focus is to investigate the solar irradiance in Tromsø using 2-axis tracking measurements from May 2020. The reduction of global irradiance and direct irradiance is also compared against the values of the other ...
    • An investigation of the spatial and temporal distribution of kinetic energy in the mesosphere. The high latitude mesosphere 

      Nordaunet, Ole Kalstad (Master thesis; Mastergradsoppgave, 2020-06-29)
      The mesosphere is perhaps the least explored region in the atmosphere with very few methods of observing. This thesis will primarily be exploring a new technique for measuring the distribution of kinetic energy in the mesosphere across a wide range of spatial and temporal scales. The method being used relies on correlation functions between pairs of meteor measurements. These measurements are made ...
    • Analysis of the potential of the Ku-band Gamma Portable Radar Interferometer for sea ice information extraction. 

      Asbjørnslett, Andreas Hansen (Master thesis; Mastergradsoppgave, 2020-06-29)
      Radar remote sensing is a key technology for monitoring sea ice. In this regard, passive microwave and Synthetic Aperture Radars (SARs) are the most important sensor types. This technology has been used for sea ice applications for four decades, but there are still many uncertainties related to sea ice monitoring by SAR. Some of these may be solved by multi-sensor observations, in which case other ...
    • Determining optical-flow for turbulent motions in the aurora borealis 

      Jakobsen, Kim André (Master thesis; Mastergradsoppgave, 2020-06-28)
      In dynamic aurora there are structures that shows shear-flow and rotations. These flows have a locally varying vorticity-field, which can be observed in small scale aurora. Vorticity in plasma-flows have a direct relation to field-aligned currents. An effective method to determine these flows would be a great tool in research on magnetosphere-ionosphere coupling and auroral physics. With the current ...
    • Investigating the viability of lithium-ion battery - fuel cell hybrid systems - A case study for Greenland and Qatar 

      Witt, Hannes (Master thesis; Mastergradsoppgave, 2020-06-22)
      Renewable means of energy production have recently become cost competitive with fossil fuels. However, before they can be completely phased out, the issue of storing renewable energy must be addressed. Two energy storage technologies that have gotten a lot of attention over the past years are lithium ion batteries and hydrogen energy storage. Each of these technologies have their advantages, ...
    • Assessment of the Remaining Carbon Budget: Incorporating Arctic Amplification in a Simple Response Model 

      Johansen, Andreas (Master thesis; Mastergradsoppgave, 2020-06-15)
      Remaining carbon budgets (RCBs) quantify the total amount of CO2 that can still be emitted into the atmosphere while keeping the global mean surface temperature below a specific target. However, there is significant uncertainty in RCBs estimates. This thesis develops a Simple Response Model (SRM) to explore the uncertainties in RCBs. We use temperature response functions estimated from multi-box ...
    • Assessment of the Remaining Carbon Budget: Incorporation of Nonlinear Feedbacks in a Simple Response Model 

      Mentzoni, Endre Falck (Master thesis; Mastergradsoppgave, 2020-06-15)
      Anthropogenic emission of greenhouse gases is causing an unbalance in the Earth’s climate system, leading to global climate change. The implications of these changes are dramatic, with a need for a global-scale assessment. The remaining carbon budget (RCB) is a measure of the amount of greenhouse gasses (GHGs) that can be emitted if we are to reach a specific temperature target. Traditionally, carbon ...
    • Evaluation of a Solar Power Plant at Longyearbyen 

      Enoksen, Thomas Oxlund (Master thesis; Mastergradsoppgave, 2020-06-15)
      The world faces one of the greatest challenges by changing the economy in a direction where higher resource productivity and lower greenhouse gas emis- sions are the main focus. The most prominent solution to reduce green house gases is a greater utilisation of renewable energy sources. With a rapid tech- nological advancement, solar energy is now one of the least expensive forms of power in two ...
    • Assessment of the Remaining Carbon Budget: A Comparison of a Simple Response Model and the MAGICC Model. 

      Martinsen, Andreas Rostrup (Master thesis; Mastergradsoppgave, 2020-06-15)
      We are changing the global climate by altering the Earths energy balance through the emission of greenhouse gasses. The international community aims to prevent dangerous warming with mitigative efforts. A remaining carbon budget (RCB) can roughly quantify an allowable amount of emissions for keeping the temperature below a set target. We have built a simple climate model using impulse response ...
    • Deep Learning of Oriented Bounding Box Regression Networks for Ship Detection in Optical Satellite Images 

      Sandland, Åsmund Mikael (Master thesis; Mastergradsoppgave, 2020-05-31)
      Maritime surveillance is important for management of maritime traffic and to prevent activities like illegal fishing, hazardous cargo transportation, piracy, and smuggling of goods and humans. Remote sensing is frequently used for positioning vessels that are not transmitting via the Automatic Identification System (AIS). Modern optical remote sensing instruments provide high-resolutional imagery, ...
    • Dust sputtering within the inner heliosphere: a modelling study 

      Baumann, Carsten; Myrvang, Margaretha; Mann, Ingrid (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-03)
      The aim of this study is to investigate how sputtering by impacting solar wind particles influence the lifetime of dust particles in the inner heliosphere near the Sun.<p><p> We consider three typical dust materials: silicate, Fe<sub>0.4</sub>Mg<sub>0.6</sub>O and carbon and describe their sputtering yields based on atomic yields given by the Stopping and Range of Ions in Matter (SRIM) package. ...
    • Can Mineral Oil Slicks Be Distinguished From Newly Formed Sea Ice Using Synthetic Aperture Radar? 

      Johansson, Malin; Espeseth, Martine; Brekke, Camilla; Holt, Benjamin (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-18)
      In this feasibility study discriminating oil slicks and newly formed sea ice using SAR imagery is investigated, using imagery from the L-band high-resolution Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) airborne and the satellite C-band RADARSAT-2 (RS-2) systems. To determine the separability of these two varying but similar appearing low backscatter ocean surfaces, multi-polarization ...
    • Auroral classification ergonomics and the implications for machine learning 

      McKay, Derek; Kvammen, Andreas (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-09)
      The machine-learning research community has focused greatly on bias in algorithms and have identified different manifestations of it. Bias in training samples is recognised as a potential source of prejudice in machine learning. It can be introduced by the human experts who define the training sets. As machine-learning techniques are being applied to auroral classification, it is important to identify ...
    • Road Transportation Challenges in the Arctic 

      Barjouei, A. Shojaei; Gudmestad, Ove T.; Barabady, Javad (Journal article; Tidsskriftartikkel; Peer reviewed, 2020)
      Despite all efforts to mitigate global warming, its rate and magnitude are still rising where transportation is considered to be an important contributor. In the Arctic regions however, unstable weather conditions, strong seasonal variations, and long harsh winters result in additional challenges to transportation in different ways such as those related to environment, human health, safety, and ...
    • Methods and Evaluation Criteria for Apps and Digital Interventions for Diabetes Self-Management: Systematic Review 

      Larbi, Dillys; Randine, Pietro; Årsand, Eirik; Antypas, Konstantinos; Bradway, Meghan; Gabarron, Elia (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-06)
      <i>Background</i>: There is growing evidence that apps and digital interventions have a positive impact on diabetes self-management. Standard self-management for patients with diabetes could therefore be supplemented by apps and digital interventions to increase patients’ skills. Several initiatives, models, and frameworks suggest how health apps and digital interventions could be evaluated, but ...
    • Reduce bandwidth in live-streaming by cooperative edge relay networks 

      Knudsen, Tor Seivaag (Master thesis; Mastergradsoppgave, 2020-06-30)
      Live-streaming and particular live video-streaming are becoming increasingly popular as a multimedia-service. More and more types of content and events are live-streamed. Live video-streaming has shown to be a useful tool in the case of pandemic outbursts such as Covid-19. As people should use social distancing, live video-streaming can give people the ability to simulate conventional social ...
    • Safe and secure outsourced computing with fully homomorphic encryption and trusted execution environments 

      Singh, Isak Sunde (Master thesis; Mastergradsoppgave, 2020-06-30)
      Increases in data production and growing demands for more computing power leads to the current trend of outsourcing data and computation services to cloud providers. With data breaches and cases of data misuse becoming increasingly common, there is a high demand for secure systems. This, however, conflicts with the current data trust models. A solution to this that is becoming more common is the use ...
    • Trends in seismic data acquisition in areas with surface ice 

      Hussain, Azeem; Gudmestad, Ove Tobias; Barabady, Javad (Peer reviewed; Bok; Chapter, 2019)
      The Arctic has great significance in relation to the exploration and exploitation of its huge petroleum resources. Seismic surveys are the key part of petroleum exploration. Reflected sound waves are used to produce a 3D subsurface geological model, which helps to take a decision on drilling location for potential hydrocarbon resources. Seismic surveys are very complex operations, and growing energy ...
    • Validation of prediction models of severe disease course and non-achievement of remission in juvenile idiopathic arthritis part 2: Results of the Nordic model in the Canadian cohort 

      Henrey, Andrew; Rypdal, Veronika Gjertsen; Rypdal, Martin Wibe; Loughin, Thomas; Nordal, Ellen Berit; Guzman, Jaime (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-15)
      <b>Background</b> Validated clinical prediction models to identify children with poor prognosis at the time of juvenile idiopathic arthritis (JIA) diagnosis would be very helpful for tailoring treatments, and avoiding under- or over-treatment. Our objective was to externally validate Nordic clinical prediction models in Canadian patients with JIA. <b>Methods</b> We used data from 513 subjects ...
    • Two-Photon Absorption Cross-Sections in Fluorescent Proteins Containing Non-canonical Chromophores Using Polarizable QM/MM 

      Rossano-Tapia, Maria; Olsen, Jógvan Magnus Haugaard; Brown, Alex (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-12)
      Multi-photon absorption properties, particularly two-photon absorption (2PA), of fluorescent proteins (FPs) have made them attractive tools in deep-tissue clinical imaging. Although the diversity of photophysical properties for FPs is wide, there are some caveats predominant among the existing FP variants that need to be overcome, such as low quantum yields and small 2PA cross-sections. From a ...