Viser treff 233-252 av 290

    • Scalable computing for earth observation - Application on Sea Ice analysis 

      Khaleghian, Salman (Doctoral thesis; Doktorgradsavhandling, 2022-12-15)
      <p>In recent years, Deep learning (DL) networks have shown considerable improvements and have become a preferred methodology in many different applications. These networks have outperformed other classical techniques, particularly in large data settings. In earth observation from the satellite field, for example, DL algorithms have demonstrated the ability to learn complicated nonlinear relationships ...
    • Scale-space methodology applied to spectral feature detection, multinormality testing and the k-sample problem, and wavelet variance analysis 

      Hindberg, Kristian (Doctoral thesis; Doktorgradsavhandling, 2012-03-23)
      The number of scale-space statistical algorithms has been greatly increased over the last 15 years. The concept originated from computer vision, introduced in Lindeberg (1994). The seminal paper by Chaudhuri and Marron (1999) brought the scale-space concept into smoothing of curves and kernel density estimation through the SiZer tool. By using all relevant smoothing bandwidths, i.e., the scale part, ...
    • Scales of tectonic processes controlling fluid flow systems on the Svyatogor Ridge, Fram Strait 

      Waghorn, Kate Alyse (Doctoral thesis; Doktorgradsavhandling, 2019-06-13)
      The Svyatogor Ridge, located in the Fram strait, is a site hosting a fluid flow system. The Svyatogor Ridge is part of the inside corner high at the Knipovich Ridge-Molloy Transform fault intersection. The Knipovich Ridge is an ultra-slow, melt-poor spreading ridge with approximately 8 mm/yr spreading rate. At this northernmost segment of the Knipovich Ridge, spreading is predominantly accommodated ...
    • Seafloor depth estimation by means of interferometric synthetic aperture sonar 

      Sæbø, Torstein Olsmo (Doctoral thesis; Doktorgradsavhandling, 2010-11-19)
      The topic of this thesis is relative depth estimation using interferometric sidelooking sonar. We give a thorough description of the geometry of interferometric sonar and of time delay estimation techniques. We present a novel solution for the depth estimate using sidelooking sonar, and review the cross-correlation function, the cross-uncertainty function and the phase-differencing technique. We ...
    • Seismic characterization and source rock evaluation of Lower Cretaceous organic-rich units on the Norwegian Continental Shelf 

      Hagset, Andreas Hallberg (Doctoral thesis; Doktorgradsavhandling, 2023-04-20)
      Across the Norwegian Continental Shelf (NCS), the Upper Jurassic organic-rich shales are considered the main source rock unit charging most of the largest producing oil and gas fields. However, despite its extensive distribution across the NCS, this source rock unit is overmature and spent in the deep Cretaceous basins on the mid-Norwegian margin and the SW Barents Shelf. Documenting the presence ...
    • Seismicity of the western-Svalbard margin and its relationship with near surface fluid flow and seepage systems - A study using ocean bottom seismometers 

      Domel, Przemyslaw (Doctoral thesis; Doktorgradsavhandling, 2023-09-28)
      Methane, a high potential greenhouse gas, travels as a fluid and releases as a gas in large quantities from the seafloor. This seepage impacts marine ecosystems and in specific cases, it has potential to reach the atmosphere, and therefore affect the climate. Gas seepage is documented worldwide, but there are still large unknowns regarding seepage dynamics, faulting/fracturing of the sediments and ...
    • Signal processing techniques for the enhancement of marine seismic data 

      Sanchis, Charlotte Juliette (Doctoral thesis; Doktorgradsavhandling, 2010-11-12)
      This thesis presents several signal processing techniques applied to the enhancement of marine seismic data. Marine seismic exploration provides an image of the Earth's subsurface from reflected seismic waves. Because the recorded signals are contaminated by various sources of noise, minimizing their effects with new attenuation techniques is necessary. A statistical analysis of background noise ...
    • Small data: practical modeling issues in human-model -omic data 

      Holsbø, Einar Jakobsen (Doctoral thesis; Doktorgradsavhandling, 2019-02-08)
      Human-model data are very valuable and important in biomedical research. Ethical and economical constraints limit the access to such data, and consequently these datasets rarely comprise more than a few hundred observations. As measurements are comparatively cheap, the tendency is to measure as many things as possible for the few, valuable participants in a study. With -omics technologies it is cheap ...
    • Solar resource assessment at high latitude regions 

      Babar, Bilal (Doctoral thesis; Doktorgradsavhandling, 2019-03-22)
      There has been a growing interest in accurately estimating surface solar radiation at high latitude locations. From a Scandinavian perspective, the installed solar photovoltaic share is increasing, primarily because of the declining cost of these systems, the introduction of various economic incentives and societal push to generate one’s own clean power. In the coming years, it is anticipated that ...
    • 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 ...
    • Spatial and temporal analysis of fluid venting systems on the Norvegian-Svalbard margin 

      Hustoft, Steinar (Doctoral thesis; Doktorgradsavhandling, 2009-04-03)
    • Spatial extent of solar proton impact in the Earth's atmosphere - Observations and modeling 

      Heino, Erkka Petteri (Doctoral thesis; Doktorgradsavhandling, 2019-12-18)
      Solar proton events cause large-scale ionization in the Earth's middle atmosphere leading to chemical changes, changes in the energy budget of the middle atmosphere, and radio wave absorption. The accurate implementation of the spatial impact of solar protons and other particle ionization sources in climate models is necessary to understand the role of energetic particle precipitation in natural ...
    • Statistical Analysis of Lattice Data with Wavelet Variance Methods and Spatiotemporal Modeling of Infectious Disease Spread 

      Geilhufe, Marc (Doctoral thesis; Doktorgradsavhandling, 2013-06-26)
      The focus of this thesis is the analysis of both regular and irregular lattice data, described in three papers. Paper I presents an extension of the pyramid algorithm for efficient Maximal Overlap Discrete Wavelet Transform coefficient calculation. As opposed to common usage of two-dimensional wavelet decomposition, it here also allows for different scales in the vertical and horizontal direction. ...
    • Statistical Analysis of Medical Shapes and Directional Data 

      Schulz, Jörn (Doctoral thesis; Doktorgradsavhandling, 2013-12-18)
      The use of statistical shape analysis in medical settings has increased during the last decades. This thesis presents contributions to three major topics of statistical shape analysis with application to medical problems. These topics are: the modeling of the shape by a geometrical model, the study of rotational shape deformations and the comparison of shapes between populations. Paper I presents ...
    • Statistical Analysis of Multilook Polarimetric Radar Images with the Mellin Transform 

      Anfinsen, Stian Normann (Doctoral thesis; Doktorgradsavhandling, 2010-05-19)
      This thesis presents methods for statistical analysis of the probability distributions used to model multilook polarimetric radar images. The methods are based on a matrix-variate version of Mellin's integral transform. The proposed theoretical framework is referred to as Mellin kind statistics. It is an extension of a theory recently developed for single polarisation amplitude and intensity data ...
    • Statistical Curve Analysis: Developing Methods and Expanding Knowledge in Health 

      Uteng, Stig (Doctoral thesis; Doktorgradsavhandling, 2022-08-19)
      <p>The analysis of curves can be claimed to be the core of most scientific ventures. In this dissertation, we focus on the statistical aspect of this type of analysis. Here, the curves originate from health and food-related areas and include improvements in blood glucose measurements, classification of moles, measurements of parameters during liver transplants in pigs, and data from the monitoring ...
    • Statistical methods for scale-invariant and multifractal stochastic processes. 

      Løvsletten, Ola (Doctoral thesis; Doktorgradsavhandling, 2014-10-03)
      This thesis focuses on stochastic modeling, and statistical methods, in finance and in climate science. Two financial markets, short-term interest rates and electricity prices, are analyzed. We find that the evidence of mean reversion in short-term interest rates is week, while the “log-returns” of electricity prices have significant anti-correlations. More importantly, empirical analyses confirm ...
    • Statistical properties of intermittent fluctuations in the boundary of fusion plasmas 

      Theodorsen, Audun (Doctoral thesis; Doktorgradsavhandling, 2018-06-14)
      Fluctuation-induced plasma–wall interactions is a major concern for the next generation, high duty-cycle magnetic confinement fusion devices. The turbulence is generated in the outboard midplane transition region between the confined core plasma and the scrape-off layer where magnetic field lines intersect material walls. Here, filaments of hot and dense plasma, elongated in the field direction, ...
    • Strength and rheological evolution of the lower continental crust: an experimental study of the deformation behavior of feldspar and quartz at high pressure and temperature 

      Negrini, Marianne (Doctoral thesis; Doktorgradsavhandling, 2013-09-10)
      Models representing the strength of the lithosphere (i.e. strength-depth profiles) are mainly based on the rheological properties of the minerals quartz and feldspar that, to a large extent, are determined in laboratory-based rock deformation studies. The study of the deformation behavior of quartz and feldspar is of fundamental importance for the understanding and modeling of plate tectonics and ...