Viser treff 137-156 av 942

    • Conjugate ionospheric perturbation during the 2017 solar eclipse 

      Zhang, Shunrong; Erickson, Philip J.; Vierinen, Juha; Aa, Ercha; Rideout, William; Coster, Anthea; Goncharenko, Larisa (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-16)
      We report new findings of total electron content (TEC) perturbations in the southern hemisphere at conjugate locations to the northern eclipse on August 21, 2017. We identified a persistent conjugate TEC depletion by 10%–15% during the eclipse time, elongating along magnetic latitudes with at least ∼5° latitudinal width. As the Moon's shadow swept southward, this conjugate depletion moved northward ...
    • ConnNet: A Long-Range Relation-Aware Pixel-Connectivity Network for Salient Segmentation 

      Kampffmeyer, Michael C.; Dong, Nanqing; Liang, Xiaodan; Zhang, Yujia; Xing, Eric P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-14)
      Salient segmentation aims to segment out attention-grabbing regions, a critical yet challenging task and the foundation of many high-level computer vision applications. It requires semantic-aware grouping of pixels into salient regions and benefits from the utilization of global multi-scale contexts to achieve good local reasoning. Previous works often address it as two-class segmentation problems ...
    • Consensus Clustering Using kNN Mode Seeking 

      Myhre, Jonas Nordhaug; Mikalsen, Karl Øyvind; Løkse, Sigurd; Jenssen, Robert (Chapter; Bokkapittel, 2015-06-09)
      In this paper we present a novel clustering approach which combines two modern strategies, namely consensus clustering, and two stage clustering as represented by the mean shift spectral clustering algorithm. We introduce the recent kNN mode seeking algorithm in the consensus clustering framework, and the information theoretic kNN Cauchy Schwarz divergence as foundation for spectral clustering. In ...
    • Consistent ice and open water classification combining historical synthetic aperture radar satellite images from ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1A/B 

      Johansson, Malin; Malnes, Eirik; Gerland, Sebastian; Cristea, Anca; Doulgeris, Anthony Paul; Divine, Dmitry V; Pavlova, Olga; Lauknes, Tom Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-17)
      Synthetic Aperture Radar (SAR) satellite images are used to monitor Arctic sea ice, with systematic data records dating back to 1991. We propose a semi-supervised classification method that separates open water from sea ice and can utilise ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1 SAR images. The classification combines automatic segmentation with a manual segment selection stage. The ...
    • Consistent ice and open water classification combining historical synthetic aperture radar satellite images from ERS-1/2, Envisat ASAR, RADARSAT-2, and Sentinel-1A/B 

      Johansson, Malin; Malnes, Eirik; Gerland, Sebastian; Cristea, Anca; Doulgeris, Anthony Paul; Divine, Dmitry V; Pavlova, Olga; Lauknes, Tom Rune (Journal article; Tidsskriftartikkel, 2020)
    • A Contextually Supported Abnormality Detector for Maritime Trajectories 

      Olesen, Kristoffer Vinther; Boubekki, Ahcene; Kampffmeyer, Michael Christian; Jenssen, Robert; Christensen, Anders Nymark; Hørlück, Sune; Clemmensen, Line H. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-31)
      The analysis of maritime traffic patterns for safety and security purposes is increasing in importance and, hence, Vessel Traffic Service operators need efficient and contextualized tools for the detection of abnormal maritime behavior. Current models lack interpretability and contextualization of their predictions and are generally not quantitatively evaluated on a large annotated dataset comprising ...
    • Convergence of statistical moments of particle density time series in scrape-off layer plasmas 

      Kube, Ralph; Garcia, Odd Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
    • Coordinate Transformer: Achieving Single-stage Multi-person Mesh Recovery from Videos 

      Li, Haoyuan; Dong, Haoye; Jia, Hanchao; Huang, Dong; Kampffmeyer, Michael Christian; Lin, Liang; Liang, Xiaodan (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-15)
      Multi-person 3D mesh recovery from videos is a critical first step towards automatic perception of group behavior in virtual reality, physical therapy and beyond. However, existing approaches rely on multi-stage paradigms, where the person detection and tracking stages are performed in a multi-person setting, while temporal dynamics are only modeled for one person at a time. Consequently, their ...
    • Coordinated Cluster/Double Star and ground-based observations of dayside reconnection signatures on 11 February 2004 

      La Hoz, Cesar (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      A number of flux transfer events (FTEs) were observed between 09:00 and 12:00UT on 11 February 2004, during southward and dawnward IMF, while the Cluster spacecraft array moved outbound through the northern, highaltitude cusp and dayside high-latitude boundary layer, and the Double Star TC-1 spacecraft was crossing the dayside low-latitude magnetopause into the magnetosheath south of the ecliptic ...
    • Correction and Characterization of Radio Frequency Interference Signatures in L-band Synthetic Aperture Radar Data 

      Meyer, Franz; Nicoll, Jeremy; Doulgeris, Anthony Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Radio frequency interference (RFI) is a known issue in low-frequency radar remote sensing. In synthetic aperture radar (SAR) image processing, RFI can cause severe degradation of image quality, distortion of polarimetric signatures, and an increase of the SAR phase noise level. To address this issue, a processing system was developed that is capable of reliably detecting, characterizing, and mitigating ...
    • Correlation between Wettability and Dissolution of Calcite in Ion-Free Water 

      AlMahri, Mariam; Lu, Jin-You; Chen, Shih-Wen; Olukan, Tuza Adeyemi; Yang, Thomas Chung-Kuang; Alhassan, Saeed; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-13)
      Calcite, a prevalent mineral in the earth’s crust, plays a pivotal role in various geological and industrial processes, including carbon sequestration, water treatment, and enhanced oil recovery. Understanding how wettability (a crucial surface property influenced by the interaction between calcite and surrounding fluids) affects calcite’s dissolution is essential for optimizing these processes. We ...
    • Corrigendum to "Development of the mesospheric Na layer at 69 degrees N during the Geminids meteor shower 2010", published in Ann.Geophys., 31, 61-73, 2013 

      Dunker, Tim; Hoppe, Ulf-Peter; Stober, Gunter; Rapp, Markus (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
    • Cosmic noise absorption during solar proton events in WACCM-D and riometer observations 

      Heino, Erkka Petteri; Verronen, Pekka T.; Kero, Antti; Kalakoski, Niilo; Partamies, Noora (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-18)
      Solar proton events (SPEs) cause large‐scale ionization in the middle atmosphere leading to ozone loss and changes in the energy budget of the middle atmosphere. The accurate implementation of SPEs and other particle ionization sources in climate models is necessary to understand the role of energetic particle precipitation in climate variability. We use riometer observations from 16 riometer stations ...
    • The CPV “toolbox”: New approaches to maximizing solar resource utilization with application-oriented concentrator photovoltaics 

      Apostoleris, Harry; Stefancich, Marco; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-03)
      As the scaling of silicon PV cells and module manufacturing has driven solar energy penetration up and costs down, concentrator photovoltaic technologies, originally conceived as a cost-saving measure, have largely been left behind. The loss of market share by CPV is being locked in even as solar energy development encounters significant obstacles related to space constraints in many parts of ...
    • Crash and recovery of the potential in a toroidal plasma column, as observed by generalized conditional sampling 

      Fredriksen, Åshild; Pecseli, Hans L.; Trulsen, Jan; Fredriksen, A.A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2008)
    • Critical echo state network dynamics by means of Fisher information maximization 

      Bianchi, Filippo Maria; Livi, Lorenzo; Jenssen, Robert; Alippi, Cesare (Chapter; Bokkapittel, 2017-07-03)
      The computational capability of an Echo State Network (ESN), expressed in terms of low prediction error and high short-term memory capacity, is maximized on the so-called “edge of criticality”. In this paper we present a novel, unsupervised approach to identify this edge and, accordingly, we determine hyperparameters configuration that maximize network performance. The proposed method is ...
    • Cross-Correlation Between Polarization Channels in SAR Imagery Over Oceanographic Features 

      Brekke, Camilla; Jones, Cathleen; Skrunes, Stine; Holt, Benjamin; Espeseth, Martine; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-11)
      This letter discusses cross-correlation features de- rived from near-coincident RADARSAT-2 quad-polarimetric and RISAT-1 hybrid-polarity (HP) measurements collected during the NOrwegian Radar oil Spill Experiment in 2015 (NORSE2015). We show that the imaginary part of the cross-correlation between RH and RV is an HP parallel to the real part of the cross-correlation between HH and VV earlier ...
    • Cross-platform application of a sea ice classification method considering incident angle dependency of backscatter intensity and its use in separating level and deformed ice 

      Guo, Wenkai; Itkin, Polona; Lohse, Johannes; Johansson, Malin; Doulgeris, Anthony Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2021)
      Wide-swath C-band synthetic aperture radar (SAR) has been used for sea ice classification and estimates of sea ice drift and deformation since it first became widely available in the 1990s. Here, we examine the potential to distinguish surface features created by sea ice deformation using ice type classification of SAR data. To perform this task with extended spatial and temporal coverage, we ...
    • Cross-population evaluation of cervical cancer risk prediction algorithms 

      Elvatun, Severin; Knoors, Daan; Nygård, Mari Kiens; Uusküla, Anneli; Võrk, Andres; Nygård, Jan Franz (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-24)
      Background - Cervical cancer is a preventable disease, despite being one of the most common types of female cancers worldwide. Integrating existing programs for cervical cancer screening with personalized risk prediction algorithms can improve population-level cancer prevention by enabling more targeted screening and contrive preventive healthcare innovations. While algorithms developed for cervical ...
    • CryoSat-2 Significant Wave Height in Polar Oceans Derived Using a Semi-Analytical Model of Synthetic Aperture Radar 2011–2019 

      Heorten, Harold; Tsamados, Michel; Armitage, Thomas; Ridout, Andy; Landy, Jack Christopher (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-18)
      This paper documents the retrieval of significant ocean surface wave heights in the Arctic Ocean from CryoSat-2 data. We use a semi-analytical model for an idealised synthetic aperture satellite radar or pulse-limited radar altimeter echo power. We develop a processing methodology that specifically considers both the Synthetic Aperture and Pulse Limited modes of the radar that change close to ...