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norskBlar i tittel Fakultet for naturvitenskap og teknologi
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U-Pb geochronology of crustal evolution and orogeny Contributions from Caledonide Spitsbergen and the Precambrian West Troms Basement Complex, North Norway
(Doctoral thesis; Doktorgradsavhandling, 2011-09-23) -
U-Pb zircon provenance of metamorphosed clastic sediments in the Brusque Metamorphic Complex, Dom Feliciano Belt, southeastern Brazil
(Master thesis; Mastergradsoppgave, 2018-05-15)The Brusque Metamorphic Complex is situated in the northern part of the Dom Feliciano Belt in the state of Santa Catarina, southeastern Brazil. The complex is composed of Neoproterozoic sequences of volcanic and sedimentary rocks, which were folded and metamorphosed at greenschist to low-amphibolite facies conditions. U-Pb dating of detrital zircon grains in five samples of clastic metasedimentary ... -
U-Th chronology and formation controls of methane-derived authigenic carbonates from the Hola trough seep area, northern Norway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-20)We investigated methane-derived authigenic carbonate (MDAC) crusts and nodules from a cold seep site on the northern Norwegian continental shelf in ca. 220 m water depth to determine the timing and mode of their formation. Gas bubbling observed during remotely operated vehicle (ROV)-assisted sampling of MDAC crusts revealed ongoing seep activity. Authigenic carbonates were present as crusts on the ... -
UAV as an inspection tool for power lines in Troms: Assessment of UAVs as a viable alternative to already established methods for inspection of power lines.
(Master thesis; Mastergradsoppgave, 2018-06-02)Power line inspection is one of the most important things in a modern society, and therefore it is important that it be kept in a functional state. Because of this, many methods are used to keep it that way. There are many factors to consider before using UAVs as a viable alternative to already established methods. Factors such as robustness against harsh weather, limits to its range and battery ... -
UAV photogrammetry and structure from motion to assess calving dynamics at Store Glacier, a large outlet draining the Greenland ice sheet
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-06)This study presents the application of a costeffective, unmanned aerial vehicle (UAV) to investigate calving dynamics at a major marine-terminating outlet glacier draining the western sector of the Greenland ice sheet. The UAV was flown over Store Glacier on three sorties during summer 2013 and acquired over 2000 overlapping, geotagged images of the calving front at an ∼ 40 cm ground sampling ... -
UAV-BORNE UWB RADAR FOR SNOWPACK SURVEYS
(Research report; Forskningsrapport, 2018)In this report we summarize the capabilities and technical characteristics of our UAV-borne UWB radar system, designed for conducting snow surveys. We developed an ultrawideband snow sounder that is capable of imaging snow stratigraphy with a 5 cm range resolution. The radar can be carried by an octocopter UAV in order to carry out airborne snowpack surveys. During a demonstration on Andøya, we ... -
Ubiquitous digital health-related data: clarification of concepts
(Chapter; Bokkapittel, 2022-08-22)The increased development and use of ubiquitous digital services reinforce the trend where health-related data is generated everywhere. Data usage in different areas introduces different terms for the same or similar concepts. This adds to the confusion of what these terms represent. We aim to provide an overview of concepts and terms used in connection with digital twins and in a healthcare context. -
Ultrasonic image denoising using machine learning in point contact excitation and detection method
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-06)A point contact/Coulomb coupling technique is generally used for visualizing the ultrasonic waves in Lead Zirconate Titanate (PZT) ceramics. The point contact and delta pulse excitation produce a broadband frequency spectrum and wide directional wave vector. In ultrasonic, the signal is corrupted with several types of noises such as speckle, Gaussian, Poisson, and salt and pepper noise. Consequently, ... -
Ultrasonic imaging of pitting using multilayer synthetic aperture focusing
(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
(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
(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
(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
(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
(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
(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
(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.
(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
(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
(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
(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. ...
