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norskFakultet for naturvitenskap og teknologi
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Retrieval of Snow Depth on Arctic Sea Ice From Surface-Based, Polarimetric, Dual-Frequency Radar Altimetry
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-18)Snow depth on sea ice is an Essential Climate Variable and a major source of uncertainty in satellite altimetry-derived sea ice thickness. During winter of the MOSAiC Expedition, the “KuKa” dual-frequency, fully polarized Ku- and Ka-band radar was deployed in “stare” nadir-looking mode to investigate the possibility of combining these two frequencies to retrieve snow depth. Three approaches ... -
Evaluating Deep Q-Learning Algorithms for Controlling Blood Glucose in In Silico Type 1 Diabetes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-07)Patients with type 1 diabetes must continually decide how much insulin to inject before each meal to maintain blood glucose levels within a healthy range. Recent research has worked on a solution for this burden, showing the potential of reinforcement learning as an emerging approach for the task of controlling blood glucose levels. In this paper, we test and evaluate several deep Q-learning algorithms ... -
Statistical experiment analysis of wear and mechanical behaviour of abaca/sisal fiber-based hybrid composites under liquid nitrogen environment
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-04)Ice accretion on various onshore and offshore infrastructures imparts hazardous effects sometimes beyond repair, which may be life-threatening. Therefore, it has become necessary to look for ways to detect and mitigate ice. Some ice mitigation techniques have been tested or in use in aviation and railway sectors, however, their applicability to other sectors/systems is still in the research phase. ... -
Bulky, electron-rich, renewable: analogues of Beller's phosphine for cross-couplings
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-30)In recent years, considerable progress has been made in the conversion of biomass into renewable chemicals, yet the range of value-added products that can be formed from biomass remains relatively small. Herein, we demonstrate that molecules available from biomass serve as viable starting materials for the synthesis of phosphine ligands, which can be used in homogeneous catalysis. Specifically, ... -
Multiple Signal Classification Algorithm: A computational microscopy tool for fluorescence microscopy
(Doctoral thesis; Doktorgradsavhandling, 2023-12-11)Fluorescence Microscopy is still the most preferred tool for studying the cell's inner structures. One of the reasons for this preference is its great selectivity, which allows it to label specific types of structures and visualize them with high contrast. However, its resolution is conventionally limited due to the diffraction of light, which makes the study of cells at scales below 200 nm challenging. ... -
A long-term proxy for sea ice thickness in the Canadian Arctic: 1996-2020
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-15). This study presents a long-term winter sea ice thickness proxy product for the Canadian Arctic based on a random forest regression model – applied to ice charts and scatterometer data, trained on CryoSat-2 observations, and applying an ice type–sea ice thickness correction using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) – that provides 25 years of sea ice thickness ... -
Influence of Fluorinated Substituents on the Near-Infrared Phosphorescence of 5d Metallocorroles
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-12)The influence of fluorinated substituents on the luminescent properties of rhenium-oxo, osmium-nitrido, and gold triarylcorroles was studied via a comparison of four ligands: triphenylcorrole (TPC), tris(ptrifluoromethylphenyl)corrole (TpCF<sub>3</sub>PC), tris{3,5-bis(trifluoromethyl)- phenyl}corrole (T3,5-CF<sub>3</sub>PC), and tris(pentafluorophenyl)corrole (TPFPC). For each metal series ... -
Comparing elevation and backscatter retrievals from CryoSat-2 and ICESat-2 over Arctic summer sea ice
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-27)The CryoSat-2 radar altimeter and ICESat-2 laser altimeter can provide complementary measurements of the freeboard and thickness of Arctic sea ice. However, both sensors face significant challenges for accurately measuring the ice freeboard when the sea ice is melting in summer months. Here, we used crossover points between CryoSat2 and ICESat-2 to compare elevation retrievals over summer sea ... -
Raman-spectroscopy of extracellular vesicles and self-supervised deep learning
(Doctoral thesis; Doktorgradsavhandling, 2023-12-07)This thesis explores the prospect of a waveguide device for optical trapping and Raman spectroscopy of single biological nanoparticles. The aim of the work is to develop a Raman-on-chip device capable of training and measuring single particles in individual trapping sites, such that the throughput of the device can be increased through parallelization. The challenge posed by the induced Raman ... -
Improving spam email classification accuracy using ensemble techniques: a stacking approach
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-20)Spam emails pose a substantial cybersecurity danger, necessitating accurate classification to reduce unwanted messages and mitigate risks. This study focuses on enhancing spam email classification accuracy using stacking ensemble machine learning techniques.We trained and tested five classifiers: logistic regression, decision tree, K-nearest neighbors (KNN), Gaussian naive Bayes and AdaBoost. To ... -
Initial characterization of an iron superoxide dismutase from Thermobifida fusca
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-19)Superoxide dismutases (SODs) are enzymes that catalyze the dismutation of the superoxide radical anion into O<sup>2</sup> and H<sup>2</sup>O<sup>2</sup> in a two-step reaction. They are ubiquitous to all forms of life and four different types of metal centers are detected, dividing this class of enzymes into Cu-/Zn-, Ni-, Mn-, and Fe-SODs. In this study, a superoxide dismutase from the ... -
Super-resolution histology
(Doctoral thesis; Doktorgradsavhandling, 2023-12-05)<p>Super-resolution optical microscopy (SRM) holds great promise for the advancement of life sciences, unlocking the secrets of the minute machinery composing living organisms. While broadly accepted in cell biology, the existing SRM methods haven’t effectively breached relevant fields such as histological practice, mainly due to the complexity, elevated costs, limited throughput, and incompatibility ... -
Deep Learning for Enhanced Fault Diagnosis of Monoblock Centrifugal Pumps: Spectrogram-Based Analysis
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-31)Abstract The reliable operation of monoblock centrifugal pumps (MCP) is crucial in various industrial applications. Achieving optimal performance and minimizing costly downtime requires effectively detecting and diagnosing faults in critical pump components. This study proposes an innovative approach that leverages deep transfer learning techniques. An accelerometer was adopted to capture vibration ... -
The weakening AMOC under extreme climate change
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-06)Changes in the Atlantic Meridional Overturning Circulation (AMOC) in the quadrupled CO<sub>2</sub> experiments conducted under the sixth Coupled Model Intercomparison Project (CMIP6) are examined. Increased CO<sub>2</sub> triggers extensive Arctic warming, causing widespread melting of sea ice. The resulting freshwater spreads southward, frst from the Labrador Sea and then the Nordic Seas, and ... -
Biodiversity Impact Assessment Considering Land Use Intensities and Fragmentation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-16)Land use is a major threat to terrestrial biodiversity. Life cycle assessment is a tool that can assess such threats and thereby support environmental decision-making. Within the Global Guidance for Life Cycle Impact Assessment (GLAM) project, the Life Cycle Initiative hosted by UN Environment aims to create a life cycle impact assessment method across multiple impact categories, including ... -
Planktonic foraminifers and shelled pteropods in the Barents Sea: Seasonal distribution and contribution to the carbon pump of the living fauna, and foraminiferal development during the last three millennia
(Doctoral thesis; Doktorgradsavhandling, 2023-12-06)The Arctic Ocean in general and the Barents Sea specifically, are highly affected by the human induced carbon dioxide (CO2) emissions and increasing temperatures. Atlantification, caused by an increase in warm Atlantic Water inflow, and polar amplification, caused by a higher impact of the increasing temperatures at high latitudes, have already been observed. Moreover, the Barents Sea has been ... -
Privacy Concerns Related to Data Sharing for European Diabetes Devices
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-13)Background: Individuals with diabetes rely on medical equipment (eg, continuous glucose monitoring (CGM), hybrid closed-loop systems) and mobile applications to manage their condition, providing valuable data to health care providers. Data sharing from this equipment is regulated via Terms of Service (ToS) and Privacy Policy documents. The introduction of the Medical Devices Regulation (MDR) and In ... -
The Detection and Attribution of Northern Hemisphere Land Surface Warming (1850–2018) in Terms of Human and Natural Factors: Challenges of Inadequate Data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-28)A statistical analysis was applied to Northern Hemisphere land surface temperatures (1850–2018) to try to identify the main drivers of the observed warming since the mid-19th century. Two different temperature estimates were considered—a rural and urban blend (that matches almost exactly with most current estimates) and a rural-only estimate. The rural and urban blend indicates a long-term warming ... -
Insights into the role of three Endonuclease III enzymes for oxidative stress resistance in the extremely radiation resistant bacterium Deinococcus radiodurans
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-12)The extremely radiation and desiccation resistant bacterium Deinococcus radiodurans possesses three genes encoding Endonuclease III-like enzymes (DrEndoIII1, DrEndoIII2, DrEndoIII3). In vitro enzymatic activity measurements revealed that DrEndoIII2 is the main Endonuclease III in this organism, while DrEndoIII1 and 3 possess unusual and, so far, no detectable EndoIII activity, respectively. In ... -
Transfer Learning Based Fault Detection for Suspension System Using Vibrational Analysis and Radar Plots
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-26)The suspension system is of paramount importance in any automobile. Thanks to the suspension system, every journey benefits from pleasant rides, stable driving and precise handling. However, the suspension system is prone to faults that can significantly impact the driving quality of the vehicle. This makes it essential to find and diagnose any faults in the suspension system and rectify them ...
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