Doktorgradsavhandlinger (NT-fak): Recent submissions
Now showing items 101-120 of 312
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Late Pleistocene-Holocene history of Svalbard ice caps and glaciers – integrating marine, terrestrial and lacustrine archives
(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 ... -
On Automated Classification of Sea Ice Types in SAR Imagery
(Doctoral thesis; Doktorgradsavhandling, 2021-03-12)With the Arctic sea ice continuously decreasing in both extent and thickness, fast and robust production of reliable ice charts becomes more important to ensure the safety of Arctic operations. This thesis focuses on the development of automated algorithms for the mapping of sea ice from synthetic aperture radar (SAR) images. It presents a thorough background on the topics of sea ice observations ... -
Determination of the Dielectric Properties of Marine Surface Slicks Using Synthetic Aperture Radar
(Doctoral thesis; Doktorgradsavhandling, 2021-03-03)Over the course of the last three decades, Synthetic Aperture Radar (SAR) has proven itself to be an effective monitoring technology for marine applications. The clear benefits of using SAR as opposed to optical devices is that SAR is insensitive to cloud cover, lighting conditions and can also provide imagery to a high degree of resolution. Given these benefits, there is a large incentive to implement ... -
Vibrational spectroscopy beyond the harmonic approximation with the Polarizable Embedding model
(Doctoral thesis; Doktorgradsavhandling, 2021-02-23)In order to efficiently and accurately calculate vibrational properties for solvated systems, a theoretical framework for combining response theory with the Polarizable Embedding model (PE) has been derived and implemented, and is presented in this thesis. An open-ended recursive formalism is utilized through the implementation in OpenRSP, allowing energy-derivatives to be calculated analytically ... -
Deep Generative Models in Credit Scoring
(Doctoral thesis; Doktorgradsavhandling, 2021-02-05)Banks need to develop effective credit scoring models to better understand the relationship between customer information and the customer's ability to repay the loan. The output of such a model is called the default probability and is used to rank loan applications in terms of their creditworthiness. The focus of this thesis is to develop novel credit scoring methodologies that solve well-known ... -
Bringing optical nanoscopy to life - Super-resolution microscopy of living cells
(Doctoral thesis; Doktorgradsavhandling, 2021-01-29)Microscopy is possibly the best tool we have to peer into the microscopic world to enhance our understanding of the usually invisible, but highly complex and vital events every moment taking place inside living cells. Microscopy is brilliant, but also has its physical constraints and technical limitations. Technical advances have in the last decade pushed optical microscopy past physical limits ... -
Leveraging Kernels for Unsupervised Learning
(Doctoral thesis; Doktorgradsavhandling, 2020-12-11)<p>Kernel methods have been a central part of the machine learning arsenal for several decades. Within this framework, unsupervised learning has been a particularly challenging area. This is due to the inherent nature of unsupervised learning tasks, where important information about the structure of the data is unknown to the user, and as such it is difficult to design a kernel or system to solve ... -
Performance Measurement System in complex environment: observed and unobserved risk factors
(Doctoral thesis; Doktorgradsavhandling, 2020-12-04)<p>World demand for energy leads industry to harvest energy in complex environment with harsh conditions and sensitive areas, such as the Arctic region – one of the last remaining wild places in the world – with potentially harmful consequences. Moreover, over the past few decades, the increasing trend of melting sea ice in the Arctic has provided increased access and has created new opportunities ... -
Diggi: A Distributed Serverless Runtime for Developing Trusted Cloud Services
(Doctoral thesis; Doktorgradsavhandling, 2020-10-30)Cloud computing offers the convenience of outsourcing storage and processing power to a public shared environment. Physical infrastructure is managed by the cloud provider, allowing hosted services to be deployed without any upfront investment. Cloud infrastructure may additionally manage deployment, migration, scalability, and fault tolerance, transparently from the hosted service. Serverless ... -
Method development towards synthesis of carbapenemase inhibitors
(Doctoral thesis; Doktorgradsavhandling, 2020-10-26)Carbapenemases are enzymes able to hydrolyze the last resort b-lactam antibiotics (carbapenems), which are used for the treatment of infections caused by resistant bacteria. Carbapenemases are structurally and mechanistically classified into serine-b-lactamases (SBLs) and metallo-b-lactamases (MBLs). In order to combat the hydrolytic activity of these enzymes, combination therapy of b-lactam with ... -
On polar lows and their formation
(Doctoral thesis; Doktorgradsavhandling, 2020-09-18)Polar lows are small, but extreme cyclones that develop in marine polar air mass. They feature one of the largest natural hazards in the polar regions. Their associated strong winds, high waves, substantial amounts of snow fall, low visibility and possibility for ice accumulation on ships and airplanes cause threats for coastal communities and marine operations. Hence, accurate prediction of polar ... -
Operationalising Critical Infrastructure Resilience. From Assessment to Management
(Doctoral thesis; Doktorgradsavhandling, 2020-09-03)Over recent decades, it has been evident that society relies heavily on critical infrastructures (CIs) to provide and maintain vital societal functions, such as water, electricity and transportation. Traditionally, in order to ensure the delivery of such functions, the focus has been on protecting the infrastructures’ systems from adverse and extreme events. However, large-scale events, such as ... -
Homogeneous Metal-Mediated Carboxylation with Carbon Dioxide
(Doctoral thesis; Doktorgradsavhandling, 2020-09-04)CO<sub>2</sub> is a non-toxic, abundant and readily available gas, which has the potential to become an important carbon source in chemical synthesis. The clear advantage of CO<sub>2</sub> is its sustainability, in contrast to typical carbon sources such as oil, coal, or natural gas, which are in the process of depletion. However, the use of CO<sub>2</sub> also poses a big challenge as it features ... -
Towards Enantioselective Carboxylation and Hydrogenation Reactions (Quantum Chemical Modelling of Homogeneous Reactions)
(Doctoral thesis; Doktorgradsavhandling, 2020-08-21)With the aid of DFT methods, it is possible to get insights into the mechanistic details of homogeneous reactions, the substrate preferences and activities of catalysts. Computational methods can also help to identify the selectivity-determining factors that govern asymmetric reactions. In this thesis, DFT methods are applied in order to study the enantioselective addition of small molecules, such ... -
Unsupervised Change Detection in Heterogeneous Remote Sensing Imagery
(Doctoral thesis; Doktorgradsavhandling, 2020-06-16)<p><i>Change detection</i> is a thriving and challenging topic in remote sensing for Earth observation. The goal is to identify changes that happen on the Earth by comparing two or more satellite or aerial images acquired at different times. Traditional methods rely on homogeneous data, that is, images acquired by the same sensor, under the same geometry, seasonal conditions,and recording ... -
Efficient Bayesian analysis of long memory processes applied to climate
(Doctoral thesis; Doktorgradsavhandling, 2020-05-22)Temperature fluctuations can be described by a persistent correlation structure known as long-range dependence (LRD). This is a phenomenon which implies that the autocorrelation function follows a power-law decay and that observations may still be significantly correlated even if the temporal or spatial distance between them is large. Moreover, temperature is known to be influenced by radiative ... -
On sea-ice forecasting
(Doctoral thesis; Doktorgradsavhandling, 2020-05-15)Accurate sea-ice prediction is essential for safe operations in the Arctic and potentially also for weather forecast at high-latitudes. The increasing number of sea-ice related satellite observations in the Arctic can be used to improve the model predictions through data assimilation. For sea ice, sea-ice concentration (SIC) observations have been available for many years. Observational information ... -
Using FullFlow to manage the overwhelming flood of patients’ self-collected health data: A system that addresses acceptance barriers regarding the introduction of diabetes patients’ self-collected health data into electronic health records and medical consultations
(Doctoral thesis; Doktorgradsavhandling, 2020-03-31)Patients increasingly collect lifestyle and health-related data thanks to the explosion of sensors and healthcare applications. Multiple studies have shown that this data can be useful during consultations, resulting in more customised medical services. Moreover, this data permits clinicians to gain an overview of the patients’ conditions and enables patients to gain knowledge about the consequences ... -
Context Centric Approach of Semantic Image Annotation and Retrieval
(Doctoral thesis; Doktorgradsavhandling, 2020-03-27)This thesis proposes a novel approach to explore and extract context information attached with images, mainly gathered from social network sites. I first performed a user study, to understand the user behavior on social network sites. I inferred that the relationship among users have central importance.<p> <p>To assist users to annotate images in social network, I use existing metadata gathered ... -
Reconstruction of past and present methane emission in the Arctic cold seeps using biogeochemical proxies
(Doctoral thesis; Doktorgradsavhandling, 2020-03-26)Global warming is now highly concerned by society as extreme weather is more often than ever, and the Arctic is experiencing warming twice as fast as the global mean. A large amount of carbon is stored in the forms of methane and methane hydrate in the continental margins worldwide. Methane is the most predominant gaseous compound in natural gas hydrate, which is stable under low temperature and ...