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norskFakultet for naturvitenskap og teknologi: Nye registreringer
Viser treff 1361-1380 av 5304
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An Energy Balance Model on an Infinite Line
(Master thesis; Mastergradsoppgave, 2022-06-01)The thesis is an expansion of the work Gerald R. North did in 1975 on an energy balance climate model. By considering a similar model on an infinite line, and allowing the heat diffusion coefficient to vary on the line, more complicated behaviour arose from the model. Much of Norths work was recreated on the infinite lines, but a lot of new discoveries were made. Among what was found were spontaneous ... -
Probabilistic forecasts of wind power generation in regions with complex topography using deep learning methods: An Arctic case
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-27)The energy market relies on forecasting capabilities of both demand and power generation that need to be kept in dynamic balance. Nowadays, contracts and auctions of renewable energy in a liberalized electricity market heavily rely on forecasting future power generation. The highly intermittent nature of renewable energy sources increases the uncertainty about future power generation. Since point ... -
Experimental and numerical engine cycle setup for a dual fuel hydrogen, methane, and hythane with diesel to assess the effect of water injection and nozzle geometry
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-15)In this study, the potential of gaseous fuels such as hydrogen, methane, and hythane in combination with diesel fuel is assessed in a closed loop thermodynamic framework. An experimental test is conducted with basic diesel fuel and then the model is configured based on the realistic one-cylinder diesel engine to evaluate the robustness and reliability of the simulation. The model is accurate in terms ... -
Explainability in subgraphs-enhanced Graph Neural Networks
(Journal article; Tidsskriftartikkel, 2023)Recently, subgraphs-enhanced Graph Neural Networks (SGNNs) have been introduced to enhance the expressive power of Graph Neural Networks (GNNs), which was proved to be not higher than the 1-dimensional Weisfeiler-Leman isomorphism test. The new paradigm suggests using subgraphs extracted from the input graph to improve the model’s expressiveness, but the additional complexity exacerbates an ... -
Quartz rheology constrained from constant-load experiments: Consequences for the strength of the continental crust
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-21)The mechanical properties of quartz are fundamental to control the plastic behaviour of the continental crust. Our understanding of quartz rheology is still limited in the following respects: i) the large variability of flow law parameters in the earlier literature (stress exponent n = 4 to ≤ 2 and activation energy Q = 120 to 242 kJ/mol), and ii) the difficulty to identify the rate-limiting deformation ... -
Mechanical properties and recrystallization of quartz in presence of H<inf>2</inf>O: Combination of cracking, subgrain rotation and dissolution-precipitation processes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-21)Natural quartzite samples, as-is and with 0.1 wt% of added H<sub>2</sub>O, have been deformed up to ∼30% bulk strain in axial shortening experiments with constant strain rate of ∼10<sup>−6</sup> s<sup>−1</sup> at 900 °C and 1 GPa, and in strain rate stepping ∼10<sup>−5</sup> to ∼10<sup>−7</sup> s<sup>−1</sup> at 900 °C and 1–1.5 GPa, in order to investigate the role of H<sub>2</sub>O in deformation ... -
Pronounced Suppression and X-Pattern Merging of Equatorial Ionization Anomalies After the 2022 Tonga Volcano Eruption
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-27)Following the 2022 Tonga Volcano eruption, dramatic suppression and deformation of the equatorial ionization anomaly (EIA) crests occurred in the American sector ∼14,000 km away from the epicenter. The EIA crests variations and associated ionosphere-thermosphere disturbances were investigated using Global Navigation Satellite System total electron content data, Global-scale Observations of the ... -
From European critical infrastructure protection to the resilience of European critical entities: what does it mean?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-03)The article is a public policy analysis of the development of legislation on critical infrastructure in the European Union (EU), covering 27 developed countries. More precisely, it concerns the 2022 CER Directive “on the resilience of critical entities’. This directive replaced the 2008 ECI Directive ‘on the identification and designation of European critical infrastructure and the assessment of ... -
Utilizing Alike Neighbor Influenced Similarity Metric for Efficient Prediction in Collaborative Filter-Approach-Based Recommendation System
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-17)The most popular method collaborative filter approach is primarily used to handle the information overloading problem in E-Commerce. Traditionally, collaborative filtering uses ratings of similar users for predicting the target item. Similarity calculation in the sparse dataset greatly influences the predicted rating, as less count of co-rated items may degrade the performance of the collaborative ... -
Late Quaternary terrigenous plant and coaly fragments found at Vestnesa Ridge, Fram Strait: implications for postglacial plant colonization at Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-23)One of four marine cores of glacial sediments collected from a water depth of about 1200 m at Vestnesa Ridge (west of Svalbard) contained small fragments of coal, charcoal and moss. This material was restricted to a single level, and 14C dating of bivalves both above and below indicates an age of c. 18.0–15.5 kyr BP. Chemical analyses of the coal indicate that the provenance area was from the northern ... -
Structural and fluid-migration control on hill-hole pair formation: Evidence from high-resolution 3D seismic data from the SW Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-11)Hill-hole pairs are subglacial landforms consisting of thrust-block hills and associated source depressions. Formed by evacuation of material where ice sheets have been locally frozen to the substrate, they give insights into paleo-ice-sheet dynamics. The aim of this study was to document the relationships between ancient hill-hole pairs identified on a buried glacial unconformity with the structure ... -
Automatic algorithm for determining bone and soft-tissue factors in dual-energy subtraction chest radiography
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-11)Lung cancer is currently the first leading cause of worldwide cancer deaths since the early stage of lung cancer detection is still a challenge. In lung diagnosis, nodules sometimes overlap with ribs and tissues on lung chest radiographic images, which are complex for doctors and radiologists. Dual-energy subtraction (DES) is a suitable solution to solve those issues. This article will develop an ... -
Designing, implementing, and testing a modern electronic clinical study management system – the HUBRO system
(Journal article; Tidsskriftartikkel, 2022-08-22)Clinical trials need to adapt to the rapid development of today’s digital health technologies. The fast phase these technologies are changing today, make the clinical study administration demanding. To meet this challenge, new and more efficient platforms for performing clinical trials in this domain need to be designed. Since the process of following up such trials is very time-consuming, it calls ... -
Interferometric Study of Ionospheric Plasma Irregularities in Regions of Phase Scintillations and HF Backscatter
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-08)We investigate the nature of small-scale irregularities observed in the cusp by the Twin Rockets to Investigate Cusp Electrodynamics-2 (TRICE-2) in regions of enhanced phase scintillations and high-frequency coherent radar backscatter. We take advantage of the fact that the irregularities were detected by spatially separated probes, and present an interferometric analysis of both the observed electron ... -
Structural Organization of S516 Group I Introns in Myxomycetes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-25)Group I introns are mobile genetic elements encoding self-splicing ribozymes. Group I introns in nuclear genes are restricted to ribosomal DNA of eukaryotic microorganisms. For example, the myxomycetes, which represent a distinct protist phylum with a unique life strategy, are rich in nucleolar group I introns. We analyzed and compared 75 group I introns at position 516 in the small subunit ... -
Iridium(VII)-Corrole Terminal Carbides Should Exist as Stable Compounds
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-14)Scalar-relativistic DFT calculations with multiple exchangecorrelation functionals and large basis sets foreshadow the existence of stable iridium(VII)−corrole terminal carbide derivatives. For the parent compound Ir[Cor](C), OLYP/STO-TZ2P calculations predict a short Ir− C bond distance of 1.69 Å, a moderately domed macrocycle with no indications of ligand noninnocence, a surprisingly low ... -
Comprehensive uncertainty estimation of the timing of Greenland warmings in the Greenland ice core records
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-20)Paleoclimate proxy records have non-negligible uncertainties that arise from both the proxy measurement and the dating processes. Knowledge of the dating uncertainties is important for a rigorous propagation to further analyses, for example, for identification and dating of stadial– interstadial transitions in Greenland ice core records during glacial intervals, for comparing the variability in ... -
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 ... -
Snowfall and snow accumulation during the MOSAiC winter and spring seasons
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-17)Data from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition allowed us to investigate the temporal dynamics of snowfall, snow accumulation and erosion in great detail for almost the whole accumulation season (November 2019 to May 2020). We computed cumulative snow water equivalent (SWE) over the sea ice based on snow depth and density retrievals from a ... -
The Influence of NegEx on ICD-10 Code Prediction in Swedish: How is the Performance of BERT and SVM Models Affected by Negations?
(Journal article; Tidsskriftartikkel, 2022-08-22)Clinical text contains many negated concepts since the physician excludes irrelevant symptoms when reasoning and concluding about the diagnosis. This study investigates the machine interpretation of negated symptoms and diagnoses using a rule-based negation detector and its influence on downstream text classification task. The study focuses on the effect of negated concepts and NegEx preprocessing ...
