Doktorgradsavhandlinger (NT-fak): Recent submissions
Now showing items 41-60 of 305
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Seismic characterization and source rock evaluation of Lower Cretaceous organic-rich units on the Norwegian Continental Shelf
(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 ... -
Cartan-Geometric Approaches to Submaximally Symmetric Ordinary Differential Equations
(Doctoral thesis; Doktorgradsavhandling, 2023-04-12)This thesis is concerned with a symmetry classification problem for ordinary differential equations (ODEs) that dates back to Sophus Lie. We focus on higher order ODEs, i.e. scalar ODEs of order greater than or equal to 4 or vector ODEs of order greater than or equal to 3, up to contact transformations. The maximal contact symmetry algebra dimensions for these ODEs are known. We determine for ... -
Optical remote sensing of water quality parameters retrieval in the Barents Sea
(Doctoral thesis; Doktorgradsavhandling, 2023-03-31)<p>This thesis addresses various aspects of monitoring water quality indicators (WQIs) using optical remote sensing technologies. The dynamic nature of aquatic systems necessitate frequent monitoring at high spatial resolution. Machine learning (ML)-based algorithms are becoming increasingly common for these applications. ML algorithms are required to be trained by a significant amount of training ... -
Risk and Resilience Assessment of Wind Farms Performance in Cold Climate Regions
(Doctoral thesis; Doktorgradsavhandling, 2023-03-13)Wind energy conversion systems such as wind farms are growing in numbers and capacity all over the globe. The onshore wind energy generation sector witnessed an increase of approximately 144 TWh during 2020, with onshore wind farms capacity addition of 108 GW, which is twice as much as the added capacity during 2019 (IEA, 2021). This staggering increase in capacity imposes higher needs for improved ... -
An Integrated Data Analytics Framework for Enhancing the Environmental and Life-cycle Economic Performance in Shipping
(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 ... -
New Building Blocks for Cancer Phototherapeutics: 5d Metallocorroles
(Doctoral thesis; Doktorgradsavhandling, 2023-02-24)Corroles are ring-contracted, triprotic analogues of porphyrins. This PhD study expands earlier knowledge in particular on ReO corroles. Early on, it became apparent that ReO corroles exhibit the highest phosphorescence quantum yields among all metallocorroles. They also sensitize singlet oxygen formation and serve as oxygen sensors and as triplet-triplet annihilation upconverters. I accordingly ... -
AHL-mediated quorum sensing regulation: Role in controlling cytotoxicity, T6SSs and CRISPR-Cas systems in Aliivibrio wodanis
(Doctoral thesis; Doktorgradsavhandling, 2023-01-27)<p><i>Aliivibrio wodanis</i> has been associated with winter ulcer disease outbreaks. It has been reported that <i>A. wodanis</i> may act as a secondary pathogen in disease outbreaks and pathogenesis. The culture supernatant of <i>A. wodanis</i> causes a cytopathogenic effect (CPE) in various salmon cell lines. Moreover, in an Atlantic salmon bath challenge experiment, <i>A. wodanis</i> alone produces ... -
A computational study of cyclic peptides with vibrational circular dichroism
(Doctoral thesis; Doktorgradsavhandling, 2022-12-16)<p>Cyclic peptides are a class of molecules that has shown antimicrobial potential. These are complex compounds to investigate with their large conformational space and multiple chiral centers. A technique that can be used to investigate both conformational preferences and absolute configuration (AC) is vibrational circular dichroism (VCD). To extract information from the experimental VCD spectra a ... -
Leveraging Supervoxels for Medical Image Volume Segmentation With Limited Supervision
(Doctoral thesis; Doktorgradsavhandling, 2022-12-16)The majority of existing methods for machine learning-based medical image segmentation are supervised models that require large amounts of fully annotated images. These types of datasets are typically not available in the medical domain and are difficult and expensive to generate. A wide-spread use of machine learning based models for medical image segmentation therefore requires the development of ... -
Scalable computing for earth observation - Application on Sea Ice analysis
(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 ... -
Biogeochemistry of dissolved organic matter in Arctic Ocean waters charged with methane
(Doctoral thesis; Doktorgradsavhandling, 2022-11-25)Dissolved organic matter (DOM) is defined as organic matter that is smaller than a nominal pore size filter (e.g., 0.7 µm) that passes through during the filtration of aquatic samples. It comprises the largest reservoir of reduced carbon (700 Pg C) in the oceans. The DOM pool is in close interaction with all the elemental cycles and food chains in the ocean and is an essential component in the marine ... -
Combinatorics of Reflection Groups and Real Algebraic Geometry
(Doctoral thesis; Doktorgradsavhandling, 2022-11-18)Real algebraic geometry studies sets defined by a finite system of real polynomial equalities and inequalities. A central topic in this area is the study of the cone of nonnegative polynomials. Verifying that a given polynomial is nonnegative is an NP-hard problem. However, it turns out to be algorithmically much more feasible to verify if a given polynomial admits a representation into a sum of ... -
Advancing Deep Learning with Emphasis on Data-Driven Healthcare
(Doctoral thesis; Doktorgradsavhandling, 2022-10-28)Retten til helse er en grunnleggende menneskerettighet, men mange utfordringer står overfor de som ønsker å etterleve denne retten. Mangel på utdannet helsepersonell, økte kostnader og en aldrende befolkning er bare noen få eksempler på nåværende hindringer i helsesektoren. Å takle slike problemer er avgjørende for å gi pålitelig helsehjelp med høy kvalitet til mennesker over hele verden. Mange ... -
Data-driven Arctic wind energy analysis by statistical and machine learning approaches
(Doctoral thesis; Doktorgradsavhandling, 2022-10-14)Norway's Arctic region is rich in wind resources and developing wind energy in the region can promote a green transition and economic development. However, the region's unique topography with fjords and mountains and cold climate conditions make wind resource assessment, generation analysis, and power forecasting particularly challenging. The accumulation of wind data and the emergence of data ... -
Holocene precipitation seasonality on Svalbard and in Northern Fennoscandia reconstructed using organic geochemical and stable isotope proxies
(Doctoral thesis; Doktorgradsavhandling, 2022-09-23)The Arctic experiences faster climate change than the global average. Feedback mechanisms between the atmosphere, cryosphere and the oceans amplify the warming, and intensify the water cycle. Arctic precipitation is projected to increase because of enhanced winter evaporation due to diminishing sea ice, increased poleward moisture transport in summer, and increased atmospheric moisture content in ... -
Ice in Norwegian subarctic fjords and coastal regions: An examination of ice formation, properties, and trends based on remote sensing and in situ data
(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 ... -
Marine natural product inspired synthesis towards new antimicrobial and antifouling agents
(Doctoral thesis; Doktorgradsavhandling, 2022-08-30)Natural products (NPs) have been the major source for the development of new small molecule drugs in modern medicine. Despite NPs being so prominent, marine natural products (MNPs) and derivatives thereof are hardly found in clinically approved agents. Therefore, using bioactive MNPs as structural guidance for drug development is a largely untapped source. The focus of the presented thesis is on ... -
Hydrological Modelling and Climate Change Impact Assessment on Future Floods in the Norwegian Arctic Catchments
(Doctoral thesis; Doktorgradsavhandling, 2022-08-26)Climate change is expected to alter the hydrological cycle in the Arctic, which would result in the increase in intensity and frequency of hydrological extreme events such as flooding. Noticeably, the changes in flooding due to climate change would severely affect human life, infrastructures, the environment, ecosystem, and socio-economic development in the impacted areas. Hydrological models are ... -
Statistical Curve Analysis: Developing Methods and Expanding Knowledge in Health
(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 ... -
Autonomous Navigation in (the Animal and) the Machine
(Doctoral thesis; Doktorgradsavhandling, 2022-07-05)Understanding the principles underlying autonomous navigation might be the most enticing quest the computational neuroscientist can undertake. Autonomous operation, also known as voluntary behavior, is the result of higher cognitive mechanisms and what is known as executive function in psychology. A rudimentary knowledge of the brain can explain where and to a certain degree how parts of a computation ...