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norskArtikler, rapporter og annet (fysikk og teknologi)
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NOIRE-Net–a convolutional neural network for automatic classification and scaling of high-latitude ionograms
(Journal article; Tidsskriftartikkel, 2024-06-03)Millions of ionograms are acquired annually to monitor the ionosphere. The accumulated data contain untapped information from a range of locations, multiple solar cycles, and various geomagnetic conditions. In this study, we propose the application of deep convolutional neural networks to automatically classify and scale high-latitude ionograms. A supervised approach is implemented and the networks ... -
Dissipation Rates of Mesospheric Stratified Turbulence From Multistatic Meteor-Radar Observations
(Journal article; Tidsskriftartikkel, 2024-06-06)Stratified turbulence (ST) has been proposed as a model for the dynamics of the mesosphere-lower thermosphere (MLT) region. This theory postulates that for horizontal mesoscales (∼1–400 km), the kinetic energy of horizontal winds dissipates from large to small scales with an approximately mean constant rate. In this investigation, dissipation rates are quantified using meteor-radar observations ... -
Plasmonic nano-bowls for monitoring intra-membrane changes in liposomes, and DNA-based nanocarriers in suspension
(Journal article; Tidsskriftartikkel, 2024-03-12)Programmable nanoscale carriers, such as liposomes and DNA, are readily being explored for personalized medicine or disease prediction and diagnostics. The characterization of these nanocarriers is limited and challenging due to their complex chemical composition. Here, we demonstrate the utilization of surface-enhanced Raman spectroscopy (SERS), which provides a unique molecular fingerprint of ... -
Application of generalized aurora computed tomography to the EISCAT-3D project
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-29)EISCAT_3D is a project to build a multi-site phased-array incoherent scatter radar system in northern Fenno-Scandinavia. We demonstrate via numerical simulation how useful monochromatic images taken by a multi-point imager network are for auroral research in the EISCAT_3D project. We apply the generalized aurora computed tomography (G-ACT) method to modelled observational data from real instruments, ... -
Influence of meteoric smoke particles on the incoherent scatter measured with EISCAT VHF
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-04)Meteoric ablation in the Earth’s atmosphere produces particles of nanometer size and larger. These particles can become charged and influence the charge balance in the D region (60–90 km) and the incoherent scatter observed with radar from there. Radar studies have shown that, if enough dust particles are charged, they can influence the received radar spectrum below 100 km, provided the electron ... -
Towards ultrafast quantitative phase imaging via differentiable microscopy [Invited]
(Journal article, 2024-02-22)With applications ranging from metabolomics to histopathology, quantitative phase microscopy (QPM) is a powerful label-free imaging modality. Despite significant advances in fast multiplexed imaging sensors and deep-learning-based inverse solvers, the throughput of QPM is currently limited by the pixel-rate of the image sensors. Complementarily, to improve throughput further, here we propose to ... -
Simulations of the collection of mesospheric dust particles with a rocket instrument
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-28)We investigate the collection of dust particles in the mesosphere with the MESS (MEteoric Smoke Sampler) instrument that is designed to fly on a sounding rocket. We assume that the ice particles that form in the polar mesosphere between 80 and 85 km altitude in summer contain meteoric smoke particles; and these should be collected with MESS. The instrument consists of a collection device with an ... -
Identification of extracellular vesicles from their Raman spectra via self-supervised learning
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-21)Extracellular vesicles (EVs) released from cells attract interest for their possible role in health and diseases. The detection and characterization of EVs is challenging due to the lack of specialized methodologies. Raman spectroscopy, however, has been suggested as a novel approach for biochemical analysis of EVs. To extract information from the spectra, a novel deep learning architecture is ... -
Knowledge and attitudes regarding pressure injuries among assistant nurses in a clinical context
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-25)This study aimed to evaluate assistant nurses' knowledge of and attitudes towards pressure injuries in a clinical setting. It employed a cross-sectional design, using two validated surveys: PUKAT 2.0 and APUP, alongside open-ended questions. A convenience sample of 88 assistant nurses from five wards across two departments at a 600-bed university hospital in Sweden participated. Participants answered ... -
High space–time bandwidth product imaging in low coherence quantitative phase microscopy
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-22)Current low coherence quantitative phase microscopy (LC-QPM) systems suffer from either reduced field of view (FoV) or reduced temporal resolution due to the short temporal coherence (TC) length of the light source. Here, we propose a hybrid, experimental and numerical approach to address this core problem associated with LC-QPM. We demonstrate high spatial resolution and high phase sensitivity in ... -
Assimilation of satellite swaths versus daily means of sea ice concentration in a regional coupled ocean–sea ice model
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-08)Operational forecasting systems routinely assimilate daily means of sea ice concentration (SIC) from microwave radiometers in order to improve the accuracy of the forecasts. However, the temporal and spatial averaging of the individual satellite swaths into daily means of SIC entails two main drawbacks: (i) the spatial resolution of the original product is blurred (especially critical in periods ... -
Sea ice transport and replenishment across and within the Canadian Arctic Archipelago, 2016-2022
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-07)The Canadian Arctic Archipelago (CAA) serves as both a source and a sink for sea ice from the Arctic Ocean, while also exporting sea ice into Baffin Bay. We use observations from Sentinel-1, RADARSAT-2, the RADARSAT Constellation Mission (RCM), and CryoSat-2, together with the Canadian Ice Service ice charts, to quantify sea ice transport and replenishment across and within the CAA from 2016 to ... -
S-polarized light-sheets improve resolution and light-efficiency in oblique plane microscopy
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-12)Oblique plane microscopy (OPM) offers 3D optically sectioned imaging with high spatial- and temporal-resolution while enabling conventional sample mounting. The technique uses a concatenation of three microscopes, two for remote focusing and a tilted tertiary microscope, often including an immersion objective, to image an oblique sample plane. This design induces Fresnel reflections and a reduced ... -
BPI-GNN: Interpretable brain network-based psychiatric diagnosis and subtyping
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-01)Converging evidence increasingly suggests that psychiatric disorders, such as major depressive disorder (MDD) and autism spectrum disorder (ASD), are not unitary diseases, but rather heterogeneous syndromes that involve diverse, co-occurring symptoms and divergent responses to treatment. This clinical heterogeneity has hindered the progress of precision diagnosis and treatment effectiveness in ... -
High-resolution imaging in acoustic microscopy using deep learning
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-18)Acoustic microscopy is a cutting-edge label-free imaging technology that allows us to see the surface and interior structure of industrial and biological materials. The acoustic image is created by focusing high-frequency acoustic waves on the object and then detecting reflected signals. On the other hand, the quality of the acoustic image's resolution is influenced by the signal-to-noise ratio, the ... -
In-Cloud Icing - A case study at Fagernesfjellet, Norway using Weather Research and Forecasting model and observations
(Chapter; Bokkapittel, 2024)Atmospheric icing poses significant challenges to infrastructure integrity and transportation safety, especially in mountainous regions such as Fagernesfjellet, Norway. This paper presents a comprehensive case study of in-cloud icing over Fagernesfjellet, leveraging hindcast data obtained through dynamic downscaling with the Weather Research and Forecasting (WRF) model alongside observational data. ... -
Resolution enhanced sea ice concentration: a new algorithm applied to AMSR2 microwave radiometry data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-30)Passive-microwave sea ice concentration (SIC) algorithms employ different frequencies and polarisations in their operational implementations. Commonly, these algorithms utilise combinations such as 19/37 GHz, yielding reduced measurement uncertainties but at a coarse spatial resolution. Alternatively, these algorithms can solely use 89 GHz, producing a higher spatial resolution but with increased ... -
Assessing the potential of Eddy detection in MIZ using SAR and Lagrangian modeling: A test case on Fram Strait
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-08-22)The analysis of ocean eddies in the marginal ice zone via remote sensing and modeling data is a challenging task. However, it is of crucial importance for various scientific applications and anthropogenic activities in the Arctic. Models often struggle to accurately represent eddies near the MIZ due to the intricate nature of sea ice-ocean interactions, unresolved small-scale processes, and ... -
Exploring the universe through dusty visions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-13)Dust in space is a universal phenomenon that can be observed within our cosmic neighbourhood. Examples include the dust from the surface of the moon to the further reaches of the outer solar system, such as Saturn’s rings, and even beyond in the galactic environment. Dust in the universe has constantly challenged astronomers’ views of heavenly bodies and phenomena, often obscuring light coming from ... -
Conceptualization of a vehicle-to-grid assisted nation-wide renewable energy system – A case study with spain
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-08)This study explores the potential of Vehicle-to-Grid (V2G) technology in utilizing Electric Vehicle (EV) batteries for energy storage, aiming to fulfil Spain’s 2030 and 2050 energy goals. The validated Simulink model uses 3.15 million EVs in 2030 and 22.7 million EVs in 2050 as primary energy storage. The results show that Spain can achieve its 2030 target of 42 % renewable energy by utilizing ...
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