Now showing items 4517-4536 of 4765

    • Ultrasonic imaging of pitting using multilayer synthetic aperture focusing 

      Skjelvareid, Martin Hansen; Olofsson, Tomas; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      Synthetic aperture focusing is known to increase both the lateral resolution and signal-to-noise level of pulse-echo ultrasonic images. In this paper, the use of synthetic aperture imaging for detection and sizing of pitting in a plate is considered. It is assumed that a water layer is present between the transducer and the plate, and that the pitting is on the back side of the plate, seen from the ...
    • Ultrasonic measurements of surface defects on flexible circuits using high-frequency focused polymer transducers 

      Wagle, Sanat; Habib, Anowarul; Melandsø, Frank (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-12)
      High frequency transducers made from a layer-by-layer deposition method are investigated as transducers for ultrasonic imaging. Prototypes of adhesive-free transducers with four active elements were made on a high performance PEI (Polyetherimide) substrate with precision milled spherical cavities used to produce focused ultrasonic beams. The transducer prototypes ...
    • Ultrasonic properties of all-printed piezoelectric polymer transducers 

      Wagle, Sanat; Decharat, Adit; Melandsø, Frank (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The ability of producing ultrasonic transducers from screen-printing has been explored experimentally, through printing and characterization of a large number of transducers. In an allprinted test design, 124 transducers with four different electrode sizes ranging from 1 to 4.9 mm2, were printed layer-by-layer on a high performance polyethyleneimine polymer. Inks from ferroelectric and conductive ...
    • Ultrasound sensor for biomedical applications 

      Øberg, Helge (Master thesis; Mastergradsoppgave, 2011-12-15)
      Vesicoureteral reflux (VUR) is an abnormality that causes urine to flow back from the bladder to the kidneys, which may cause renal scarring and kidney damage. A non-ionizing and non-invasive VUR diagnostic technique, based on microwave hyperthermia, is under development. The possibility for improved hyperthermia efficiency and patient safety through implementation of ultrasound transducers is the ...
    • Unbalanced low coherence interference microscopy 

      Ahmad, Azeem; Habib, Anowarul; Dubey, Vishesh Kumar; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-03)
      Low coherence interference microscopy (LCIM) provides high spatial phase sensitivity, i.e., speckle free and coherent noise free quantitative phase images of the test specimens. Due to low temporal coherence (TC) length of the light source, LCIM requires precise adjustment of the optical path difference (OPD) between the object and the reference arm, which is only a few micrometers. Consequently, ...
    • Uncertainties in Managing Atmospheric Icing on Power Lines 

      VAHHABI, MOHSEN; Barabadi, Abbas; Barabady, Javad; Nouri, Ali (Chapter; Bokkapittel, 2023)
      Icing affects the infrastructure dramatically, especially in the cold region. Therefore, applying effective ice disaster management (IDM) to provide a systematic approach to dealing with atmospheric icing on power lines is essential. It includes preparedness, response, recovery, learning, risk assessment, and prevention. Integral to this management is the accurate prediction and modeling of icing, ...
    • Uncertainty and interpretability in convolutional neural networks for semantic segmentation of colorectal polyps 

      Wickstrøm, Kristoffer Knutsen; Kampffmeyer, Michael C.; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-20)
      Colorectal polyps are known to be potential precursors to colorectal cancer, which is one of the leading causes of cancer-related deaths on a global scale. Early detection and prevention of colorectal cancer is primarily enabled through manual screenings, where the intestines of a patient is visually examined. Such a procedure can be challenging and exhausting for the person performing the screening. ...
    • Uncertainty Estimation and Visualization of Wind in Weather Forecasts 

      Fjukstad, Bård; Bjørndalen, John Markus; Anshus, Otto (Chapter; Bokkapittel, 2014-01)
      The Collaborative Symbiotic Weather Forecasting system, CSWF, let individual users do on-demand small region, short-term, and very high-resolution forecasts. When the regions have some overlap, a symbiotic forecast can be produced based on the individual forecasts from each region. Small differences in where the center of the region is located when there is complex terrain in the region, leads to ...
    • Uncertainty Modeling and Interpretability in Convolutional Neural Networks for Polyp Segmentation. 

      Wickstrøm, Kristoffer Knutsen (Master thesis; Mastergradsoppgave, 2018-05-14)
      Colorectal cancer is one of the leading causes of cancer-related deaths worldwide, with prevention commonly done through regular colonoscopy screenings. During a colonoscopy, physicians manually inspect the colon of a patient using a camera in search for polyps, which are known to be possible precursors to colorectal cancer. Seeing that a colonoscopy is a manual procedure, it can be susceptible to ...
    • Uncertainty-Aware Deep Ensembles for Reliable and Explainable Predictions of Clinical Time Series 

      Wickstrøm, Kristoffer Knutsen; Mikalsen, Karl Øyvind; Kampffmeyer, Michael; Revhaug, Arthur; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-07)
      Deep learning-based support systems have demonstrated encouraging results in numerous clinical applications involving the processing of time series data. While such systems often are very accurate, they have no inherent mechanism for explaining what influenced the predictions, which is critical for clinical tasks. However, existing explainability techniques lack an important component for trustworthy ...
    • Uncovering Contributing Factors to Interruptions in the Power Grid: An Arctic Case 

      Chiesa, Matteo; Bianchi, Filippo Maria; Eikeland, Odin Foldvik; Holmstrand, Inga Setså; Bakkejord, Sigurd; Santos, Sergio (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-03)
      Electric failures are a problem for customers and grid operators. Identifying causes and localizing the source of failures in the grid is critical. Here, we focus on a specific power grid in the Arctic region of Northern Norway. First, we collected data pertaining to the grid topology, the topography of the area, the historical meteorological data, and the historical energy consumption/production data. ...
    • Uncovering hidden structures: previously undescribed pseudopodia and ectoplasmic structures in planktonic foraminifera 

      Greco, Mattia; Westgård, Adele; Sykes, Freya Elizabeth; Mohamed, Mohamed Mahmoud Ezat Ahmed; Meilland, Julie (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-05)
      The trophic strategies of cold-water planktonic foraminifera are not well understood due to the challenge of culturing them in polar conditions. Here, we identify previously unknown ectoplasmic and cytoplasmic projections in three species of planktonic foraminifera thriving in polar and subpolar marine environments: Globigerina bulloides, Neogloboquadrina incompta and Neogloboquadrina pachyderma. ...
    • Underexplored continental shelf gateways: timing, mechanisms and role of SW Barents Sea Gateway, Norwegian Arctic 

      Lasabuda, Amando P. E.; Hanssen, Alfred; Laberg, Jan Sverre; Rydningen, Tom Arne; Patton, Henry; Faleide, Jan Inge; Abdelmalak, Mohamed Mansour; Kjølhamar, Bent (Conference object; Konferansebidrag, 2022)
      Ocean gateways connecting ocean basins are crucial for water and heat circulation, which influence global temperature, climate evolution and sediment distribution. While deep-water gateways have been a major research focus by the community, very little attention has been drawn to shallower gateways located on the continental shelves, where such circulation also takes place. In this study, we investigate ...
    • Undersjøiske daler og oljereservoar 

      Vorren, Tore Ola; Laberg, Jan Sverre (Chronicle; Kronikk, 2010-10-02)
    • Undersjøiske kjempeskred og flodbølger 

      Vorren, Tore Ola; Laberg, Jan Sverre (Chronicle; Kronikk, 2010-09-25)
    • Undersjøiske skred i Balsfjorden, Nord-Norge: egenskaper og sammensetning 

      Iversen, Vera (Master thesis; Mastergradsoppgave, 2014-06-02)
      Batymetridata, høyoppløselige seismisk data samt en sedimentkjerne fra indre Balsfjorden, Troms, nord-Norge, har blitt analysert for å undersøke sedimentasjonsprosesser i løpet av Holocen, med spesiell fokus på undersjøiske rasavsetninger. Hovedvekt av denne oppgaven ligger på analyse av den 8,67 m lange sedimentkjernen JM11-001-PC. Dette inkluderte beskrivelse av sedimentoverflate og røntgen ...
    • Understanding and predicting one- and two-photon absorption properties of molecular complexes 

      Steindal, Arnfinn Hykkerud (Doctoral thesis; Doktorgradsavhandling, 2013-01-22)
      This thesis presents the development of theoretical models for the calculations of one- and two-photon absorption, and computational studies on solvated systems and biomolecules. The photon-absorbing chromophore is described by density functional theory, while the effects of the surroundings are taken into account by means of polarizable embedding models. The theory and implementation of a three-layered ...
    • Understanding Cassini RPWS Antenna Signals Triggered by Dust Impacts 

      Ye, Sheng - Yi; Vaverka, Jakub; Nouzak, Libor; Sternovsky, Zoltan; Zaslavsky, Arnaud; Pavlu, Jirka; Mann, Ingrid; Hsu, Sean; Averkamp, Terrance, F.; Sulaiman, Ali H.; Pisa, D.; Hospodarsky, George; Kurth, William, S.; Horanyi, Mihaly (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-04)
      Electric field antennas are capable of detecting dust impacts in different space environment. We analyze the dust impact signals detected by the Cassini Radio and Plasma Wave Science instrument at different locations around Saturn and compare them with dust impact signals simulated in laboratory conditions and numerically. The spacecraft potential, the size, and capacitance of the impacted element ...
    • Understanding Cassini RPWS Antenna Signals Triggered by Dust Impacts 

      Ye, Shengyi; Vaverka, Jakub; Nouzak, Libor; Sternovsky, Zoltan; Zaslavsky, Arnaud; Mann, Ingrid; Hsu, H-W.; Averkamp, Terrance, F.; Sulaiman, AH; Pisa, D.; Hospodarsky, G. B.; Kurth, W.S.; Horanyi, M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-04)
      Electric field antennas are capable of detecting dust impacts in different space environment. We analyze the dust impact signals detected by the Cassini Radio and Plasma Wave Science instrument at different locations around Saturn and compare them with dust impact signals simulated in laboratory conditions and numerically. The spacecraft potential, the size, and capacitance of the impacted element ...
    • Understanding Hyperporphyrin Spectra: TDDFT Calculations on Diprotonated Tetrakis(p-aminophenyl)porphyrin 

      Conradie, Jeanet; Wamser, Carl C.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-29)
      A detailed TDDFT study (with all-electron STO-TZ2P basis sets and the COSMO solvation model) has been carried out on the effect of diprotonation on the UV−vis−NIR spectra of free-base tetraphenylporphyrin and tetrakis(p-aminophenyl)porphyrin. The diprotonated forms have been modeled as their bis-formate complexes, i.e., as so-called porphyrin diacids. The dramatic redshift of the Q-band of ...