Artikler, rapporter og annet (fysikk og teknologi): Nye registreringer

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    • Recognizing Hand-Based Micro Activities Using Wrist-Worn Inertial Sensors: A Zero-Shot Learning Approach 

      Machot, Fadi Al; Ullah, Habib; Demrozi, Florenc (Chapter; Bokkapittel, 2024-10-23)
      Zero-shot learning (ZSL) is a machine learning paradigm that enables models to recognize and classify data from classes they have not encountered during training. This approach is particularly advantageous in recognizing activities where labeled data is limited, allowing models to identify new, unseen activities by leveraging semantic knowledge from seen activities. In this paper, we explore the ...

    • Automatic Generation of Contrast Maps in Terms of van der Waals Material Properties in Bimodal AFM 

      Santos Hernandez, Sergio; Elsherbiny, Lamiaa; Lai, Chia-Yun; Askar, Khalid; Gadelrab, Karim; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-11-26)
      van der Waals (vdW) forces are of interest in colloid science, biophysics, cell biology, and the field of vdW heterostructures. We present a model and method to quantify vdW material properties of samples routinely in standard bimodal atomic force microscopy (AFM) without the need to establish mechanical contact with the samples. The method preserves the high resolution of bimodal AFM but ...

    • A position and wave spectra dataset of Marginal Ice Zone dynamics collected around Svalbard in 2022 and 2023 

      Rabault, Jean; Taelman, Catherine Cecilia A; Idzanovic, Martina; Hope, Gaute; Nose, Takehiko; Kristoffersen, Yngve; Jensen, Atle; Breivik, Øyvind; Bryhni, Helge; Hoppmann, Mario; Demchev, Denis; Korosov, Anton; Johansson, Anna Malin Kristin; Eltoft, Torbjørn; Dagestad, Knut-Frode; Röhrs, Johannes; Eriksson, Leif; Durán Moro, Marina; Rikardsen, Edel; Waseda, Takuji; Kodaira, Tsubasa; Lohse, Johannes Philipp; Desjonquères, Thibault; Olsen, Sveinung Viggo; Gundersen, Olav; Martins de Aguiar, Victor Cesar; Karlsen, Truls Thorsen; Babanin, Alexander V.; Voermans, Joey J.; Park, Jeong-Won; Müller, Malte (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-12-21)
      Sea ice is a key element of the global Earth system, with a major impact on global climate and regional weather. Unfortunately, accurate sea ice modeling is challenging due to the diversity and complexity of underlying physics happening there, and a relative lack of ground truth observations. This is especially true for the Marginal Ice Zone (MIZ), which is the area where sea ice is affected by ...

    • A Practical Approach to FMCW Radar Deconvolution in the Sea Ice Domain 

      Newman, Thomas; Stroeve, Julienne C.; Nandan, Vishnu; Willatt, Rosemary C.; Mead, James B.; Mallett, Robbie David Christopher; Tsamados, Michel; Huntemann, Marcus; Hendricks, Stefan; Spreen, Gunnar; Tonboe, Rasmus T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-11-19)
      This paper presents a practical step-by-step approach to Frequency Modulated Continuous Wave (FMCW) radar nonlinearity correction (deconvolution), utilizing surface-based Ku- and Ka-band radar data collected over nilas ice within a newly-opened sea ice lead during the 2019/2020 MOSAiC expedition. Two performance metrics are introduced to evaluate deconvolution effectiveness: the spurious free ...

    • Heavy Molecular and Metallic Ions in the Magnetosphere 

      Yamauchi, M.; Christon, S.; Dandouras, I.; Haaland, Stein Egil; Kastinen, D.; Kistler, L.M.; Mann, Ingrid Brigitte; Nozawa, S.; Plane, J.M.C.; Saito, Y.; Schulz, L.; Watababe, S.; Wurz, P.; Yau, A.W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-11-04)
      Observations and present knowledge of heavy ions with mass ≥ 27 in the magnetosphere are reviewed. There are four ultimate sources of these heavy ions: the solar wind (mainly high charge-state atomic ions), the ionosphere (mainly molecular ions), the atmospheric metal layers that originate ultimately from ablation of meteoroids and possibly space debris (low charge-state metallic ions and metal-rich ...

    • The Growth and Decay of Intense GNSS Amplitude and Phase Scintillation During Non‐Storm Conditions 

      Madhanakumar, Mahith; Spicher, Andres; Vierinen, Juha-Pekka; Oksavik, Kjellmar; Coster, Anthea J.; Huyghebaert, Devin Ray; Martin, Carley J.; Häggström, Ingemar; Paxton, Larry J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-11-30)
      A multi‐instrument study is conducted at the dayside polar ionosphere to investigate the spatio‐ temporal evolution of scintillation in Global Navigation Satellite System (GNSS) signals during non‐storm conditions. Bursts of intense amplitude and phase scintillation started to occur at ∼9 MLT and persisted for more than 1 hour implying the simultaneous existence of Fresnel and large‐scale sized ...

    • Impact of varying solar angles on Arctic iceberg area retrieval from Sentinel-2 near-infrared data 

      Fisser, Henrik; Doulgeris, Anthony Paul; Høyland, Knut Vilhelm (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-11-18)
      Icebergs are part of the glacial mass balance and they interact with the ocean and with sea ice. Optical satellite remote sensing is often used to retrieve the above-waterline area of icebergs. However, varying solar angles introduce an error to the iceberg area retrieval that had not been quantified. Herein, we approximate the iceberg area error for top-of-atmosphere Sentinel-2 near-infrared data ...

    • Baffin Bay Ice Export and Production From Sentinel-1, the RADARSAT Constellation Mission, and CryoSat-2: 2016–2022 

      Howell, S.E.L.; Babb, D.G.; Landy, Jack Christopher; Moore, G.W.K.; Ballinger, T.J.; McNeil, K.; Montpetit, B.; Brady, M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-11-13)
      Baffin Bay is located between Greenland and several islands of the Canadian Arctic, providing a conduit for the downstream transport of ice and freshwater to the North Atlantic via Davis Strait. Using satellite observations from Sentinel‐1, the RADARSAT Constellation Mission, and CryoSat‐2, we estimated the sea ice export through Davis Strait and winter ice production in Baffin Bay from 2016 to ...

    • fair-calibrate v1.4.1: calibration, constraining, and validation of the FaIR simple climate model for reliable future climate projections 

      Smith, Christopher J.; Cummins, Donald; Fredriksen, Hege-Beate; Nicholls, Zebedee; Meinshausen, Malte; Allen, Myles; Jenkins, Stuart; Leach, Nicholas; Mathison, Camilla; Partanen, Antti-Ilari (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-12-03)
      Simple climate models (also known as emulators) have re-emerged as critical tools for the analysis of climate policy. Emulators are efficient and highly parameterised, where the parameters are tunable to produce a diversity of global mean surface temperature (GMST) response pathways to a given emission scenario. Only a small fraction of possible parameter combinations will produce historically ...

    • Studentaktiv læring med store studentgrupper: flervalgsoppgaver i sentrum 

      Micheron, David; Beerepoot, Maarten (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-16)
      To viktige prinsipper for å øke studentenes læring i undervisning er aktiv deltagelse og formativ vurdering. Innføring av disse prinsippene i undervisning med store studentgrupper kan imidlertid by på utfordringer, særlig i nettbasert undervisning. En mulig løsning kan være bruk av flervalgsoppgaver som diagnostisk testing med innsamling av svarene og påfølgende formativ vurdering – en undervisningsform ...

    • Bringing it all together: Science priorities for improved understanding of Earth system change and to support international climate policy 

      Jones, Colin G.; Adloff, Fanny; Booth, Ben B. B.; Cox, Peter M.; Eyring, Veronika; Friedlingstein, Pierre; Frieler, Katja; Hewitt, Helene T.; Jeffery, Hazel A.; Joussaume, Sylvie; Koenigk, Torben; Lawrence, Bryan N.; O'Rourke, Eleanor; Roberts, Malcolm J.; Sanderson, Benjamin M.; Séférian, Roland; Somot, Samuel; Vidale, Pier Luigi; Van Vuuren, Detlef; Acosta, Mario; Bentsen, Mats; Bernardello, Raffaele; Betts, Richard; Blockley, Ed; Boé, Julien; Bracegirdle, Tom; Braconnot, Pascale; Brovkin, Victor; Buontempo, Carlo; Doblas-Reyes, Francisco; Donat, Markus; Epicoco, Italo; Falloon, Pete; Fiore, Sandro; Frölicher, Thomas; Fučkar, Neven S.; Gidden, Matthew J.; Goessling, Helge F.; Graversen, Rune Grand; Gualdi, Silvio; Gutiérrez, José M.; Ilyina, Tatiana; Jacob, Daniela; Jones, Chris D.; Juckes, Martin; Kendon, Elizabeth; Kjellström, Erik; Knutti, Reto; Lowe, Jason; Mizielinski, Matthew; Nassisi, Paola; Obersteiner, Michael; Regnier, Pierre; Roehrig, Romain; Salas Y Mélia, David; Schleussner, Carl-Friedrich; Schulz, Michael; Scoccimarro, Enrico; Terray, Laurent; Thiemann, Hannes; Wood, Richard A.; Yang, Shuting; Zaehle, Sönke (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-10-18)
      We review how the international modelling community, encompassing integrated assessment models, global and regional Earth system and climate models, and impact models, has worked together over the past few decades to advance understanding of Earth system change and its impacts on society and the environment and thereby support international climate policy. We go on to recommend a number of priority ...

    • Sea ice mass balance during the MOSAiC drift experiment: Results from manual ice and snow thickness gauges 

      Raphael, Ian A.; Perovich, Donald K.; Polashenski, Christopher M.; Clemens-Sewall, David; Itkin, Polona; Lei, Ruibo; Nicolaus, Marcel; Regnery, Julia; Smith, Madison M.; Webster, Melinda; Jaggi, Matthias (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-09)
      Precise measurements of Arctic sea ice mass balance are necessary to understand the rapidly changing sea ice cover and its representation in climate models. During the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition, we made repeat point measurements of snow and ice thickness on primarily level first- and second-year ice (FYI, SYI) using ablation stakes and ...

    • Point-cloud clustering and tracking algorithm for radar interferometry 

      Ivarsen, Magnus Fagernes; St‐Maurice, Jean-Pierre; Hussey, Glenn C.; Huyghebaert, Devin Ray; Gillies, D. Megan (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-10-22)
      In data mining, density-based clustering, which entails classifying datapoints according to their distributions in some space, is an essential method to extract information from large datasets. With the advent of software-based radio, ionospheric radars are capable of producing unprecedentedly large datasets of plasma turbulence backscatter observations, and new automatic techniques are needed to ...

    • Polar mesospheric summer echo (PMSE) multilayer properties during the solar maximum and solar minimum 

      Jozwicki, Dorota; Sharma, Puneet; Huyghebaert, Devin Ray; Mann, Ingrid Brigitte (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-11-11)
      Polar mesospheric summer echoes (PMSEs) are radar echoes that are measured in the upper atmosphere during the summer months and that can occur in several layers. In this study, we aimed to investigate the relationship between PMSE layers ranging from 80 to 90 km altitude and the solar cycle. We investigated 230 h of observations from the EISCAT very high frequency (VHF) radar located near Tromsø, ...

    • Deriving the Ionospheric Electric Field From the Bulk Motion of Radar Aurora in the E-Region 

      Ivarsen, Magnus Fagernes; St‐Maurice, Jean-Pierre; Huyghebaert, Devin Ray; Gillies, D. Megan; Lind, Frank; Pitzel, Brian; Hussey, Glenn C. (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-10-28)
      In the auroral E‐region strong electric fields can create an environment characterized by fast plasma drifts. These fields lead to strong Hall currents which trigger small‐scale plasma instabilities that evolve into turbulence. Radio waves transmitted by radars are scattered off of this turbulence, giving rise to the ‘radar aurora’. However, the Doppler shift from the scattered signal does not ...

    • Co-located OLCI optical imagery and SAR altimetry from Sentinel-3 for enhanced Arctic spring sea ice surface classification 

      Chen, Weibin; Tsamados, Michel; Willatt, Rosemary; Takao, So; Brockley, David; de Rijke-Thomas, Claude; Francis, Alistair; Johnson, Thomas; Landy, Jack Christopher; Lawrence, Isobel R.; Lee, Sanggyun; Nasrollahi Shirazi, Dorsa; Liu, Wenxuan; Nelson, Connor; Stroeve, Julienne C.; Hirata, Len; Deisenroth, Marc Peter (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-10)
      The Sentinel-3A and Sentinel-3B satellites, launched in February 2016 and April 2018 respectively, build on the legacy of CryoSat-2 by providing high-resolution Ku-band radar altimetry data over the polar regions up to 81° North. The combination of synthetic aperture radar (SAR) mode altimetry (SRAL instrument) from Sentinel-3A and Sentinel-3B, and the Ocean and Land Colour Instrument (OLCI) imaging ...

    • Cross-modality sub-image retrieval using contrastive multimodal image representations 

      Breznik, Eva; Wetzer, Elisabeth; Lindblad, Joakim; Sladoje, Nataša (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-08-13)
      In tissue characterization and cancer diagnostics, multimodal imaging has emerged as a powerful technique. Thanks to computational advances, large datasets can be exploited to discover patterns in pathologies and improve diagnosis. However, this requires efficient and scalable image retrieval methods. Cross-modality image retrieval is particularly challenging, since images of similar (or even the ...

    • Overview of the First Pathloss Radio Map Prediction Challenge 

      Yapar, Cagkan; Jaensch, Fabian; Levie, Ron; Kutyniok, Gitta Astrid Hildegard; Caire, Giuseppe (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-26)
      Pathloss quantifies the reduction in power density of a signal radiated from a transmitter. The attenuation is due to large-scale effects such as free-space propagation loss and interactions (e.g., penetration, reflection, and diffraction) of the signal with objects such as buildings, vehicles, trees, and pedestrians in the propagation environment. Many current or planned wireless communications ...

    • Automated Sentinel-1 ice type mapping and in-situ validation during the CIRFA-22 cruise 

      Lohse, Johannes Philipp; Taelman, Catherine Cecilia A; Everett, Alistair; Hughes, Nick (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-13)
      We present a fully-automated workflow to map sea ice types from Sentinel-1 data and transfer the results in near real-time to the research vessel Kronprins Haakon (KPH) in order to support tactical navigation and decision-making during a research cruise conducted towards Belgica Bank in April and May 2022. We used overlapping SAR and optical imagery to train a pixel-wise classifier for the required ...

    • A three-point velocity estimation method for two-dimensional coarse-grained imaging data 

      Losada, Juan Manuel; Helgeland, Aurora Driveklepp; Terry, J.L.; Garcia, Odd Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-09-04)
      Time delay and velocity estimation methods have been widely studied subjects in the context of signal processing, with applications in many different fields of physics. The velocity of waves or coherent fluctuation structures is commonly estimated as the distance between two measurement points divided by the time lag that maximizes the cross correlation function between the measured signals, but ...