Institutt for fysikk og teknologi: Nye registreringer
Viser treff 981-1000 av 1407
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SAR imaging and detection of partially coherent targets
(Master thesis; Mastergradsoppgave, 2018-05-23)A synthetic aperture radar (SAR) achieves a high azimuth resolution by illuminating targets with multiple pulses and using the Doppler history to synthesize a large antenna. When combining the pulses, it is normally assumed that the targets are stationary, and that their reflectivity is independent of time. The topic of this thesis is the processing of SAR images where the the targets have a ... -
Optical nanoscopy of tissue sections
(Master thesis; Mastergradsoppgave, 2018-05-28)The study of organ tissues, namely, histology, is essential for clinical medicine, as it allows the identification of a wide range of diseases. Traditionally, two major techniques, optical and electron microscopy, have been used for morphological observation of tissue sections. Optical microscopy (OM) allows for fast-acquisition high-throughput imaging, at the expense of diffraction-limited resolution ... -
The Cretaceous development of the Nordkapp Basin based on seismic interpretation
(Master thesis; Mastergradsoppgave, 2018-05-31)This thesis is focused on studying the development of the Nordkapp Basin during the Cretaceous Period. The basin is fault-controlled and is strongly influenced by salt tectonics. The basin is divided into two parts, which differs both in the average width and direction of their elongation. Moreover, the salt structures in the northeast and southwest parts of the basin also follow the trends in width ... -
Estimering av egenskaper til naturlige klasser i radarbilder med en blandingsmodell
(Master thesis; Mastergradsoppgave, 2018-05-31)I løpet av de siste årene har isdekket i polhavet gått fra å være flerårsis til å bli en sesongbasert istype. Hvordan isen utvikler seg på sommeren vil avhenge av smeltevannandelen, blant annet på grunn av at smeltevannet har mindre albedo enn isen. For å estimere andelen smeltevann er det i denne oppgaven utviklet flere metoder som kan brukes på satellittbilder. Disse metodene bruker en statistisk ... -
Comparing sea ice areas identified within quad-polarimetry high-resolution SAR satellite scenes with the same areas in dual-polarimetry medium resolution SAR scenes
(Master thesis; Mastergradsoppgave, 2018-06-01)This thesis compares polarimetric features from quad-polarimetric (quad-pol) SAR (synthetic aperture radar) data and emulated dual-polarimetric (dual-pol) SAR data to investigate the information captured over sea ice areas located in the Barents Sea. The polarimetric features of entropy (H) and mean alpha, and the H/mean alpha-plot is compared, as well as the cross-polarizarion ratio and the damping ... -
The Future of Solar Energy in Marine Applications
(Master thesis; Mastergradsoppgave, 2018-06-01)The objective of this master's thesis is to investigate the current and future technical and economic feasibility of PV systems for marine applications. Two scenarios will be studied; a land-based PV power station to supply an in-land ferry in Norway and a PV system installed on a wind farm support vessel as a supplementary power source. The two scenarios are use cases that support the two research ... -
A Sensitivity Study of L-Band Synthetic Aperture Radar Measurements to the Internal Variations and Evolving Nature of Oil Slicks
(Master thesis; Mastergradsoppgave, 2018-06-01)This thesis focuses on the use of multi-polarization synthetic aperture radar (SAR) for characterization of marine oil spills. In particular, the potential of detecting internal zones within oil slicks in SAR scenes are investigated by a direct within-slick segmentation scheme, along with a sensitivity study of SAR measurements to the evolving nature of oil slicks. A simple, k-means clustering ... -
Classification of Marine Oil Spills and Look-alikes in Sentinel-1 TOPSAR and Radarsat-2 ScanSAR Images
(Master thesis; Mastergradsoppgave, 2018-06-01)The main focus of this thesis is to investigate the potential for discrimination between marine oil spills and look-alikes in Synthetic Aperture Radar (SAR) imagery, using log-cumulants and other parameters describing the characteristics of a dark feature. Look-alikes denotes other phenomena known to cause similar SAR signatures as mineral oil. It is vital for the companies managing oil detection ... -
Analyzing Behavioral Biometrics of Handwriting Using Myo Gesture Control Armband
(Master thesis; Mastergradsoppgave, 2018-06-05)Through the last few decades, computer technology has gradually merged into our everyday lives. Computers and sensors are embedded in an increasing amount of household items, enabling us to monitor and remotely control our connected devices from apps on our smartphones. The technology interfaces are also evolving along with new technologies. Among the up and coming digital interfaces are wearable ... -
An evaluation of the reanalyses ERA-Interim and ERA5 in the Arctic using N-ICE2015 data
(Master thesis; Mastergradsoppgave, 2018-06-15)The Arctic climate has changed considerably in the last few decades. Hence, a large fraction of the current studies of the Arctic climate relies on global atmospheric reanalyses, due to the shortage of meteorological observations in the Arctic. However, global climate models have shown to struggle with simulating the current conditions in the Arctic region. Thus, the objective of this thesis is to ... -
Seasonal energy storage for district heating applications, including simulation and analysis of Borehole Thermal Energy Storage systems
(Master thesis; Mastergradsoppgave, 2018-06-18)The objective of this thesis is to analyse different energy storage technologies for seasonal energy storage in combination with district heating. Tromsø receives district heating (Kvitebjørn Varme). Their new heating central at Skattøra burn waste from industry and households in Tromsø and this heat is used to heat water. A part of this excess heat is lost to air during summer because of a lower ... -
Can we extend local sea-ice measurements to satellite scale? An example from the N-ICE2015 expedition
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-17)Knowledge of Arctic sea-ice conditions is of great interest for Arctic residents, as well as for commercial usage, and to study the effects of climate change. Information gained from analysis of satellite data contributes to this understanding. In the course of using in situ data in combination with remotely sensed data, the question of how representative local scale measurements are of a wider ... -
An objective global climatology of polar lows based on reanalysis data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-04-16)Here we present an objective global climatology of polar lows. In order to obtain objective detection criteria, the efficacy of several parameters for separating polar lows from other cyclones has been compared. The comparison and the climatology are based on the ERA‐Interim reanalysis from 1979 ‐ 2016 and the high‐resolution Arctic System Reanalysis from 2000 ‐ 2012. The most effective parameters ... -
Emulating sentinel-1 Doppler radial ice drift measurements using envisat ASAR data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-05)Using data from the Envisat Advanced Synthetic Aperture Radar (ASAR) instrument, this paper demonstrates how the high-precision radial surface velocity product, which will become available with the European Space Agency's Sentinel-1 satellite, can complement the analysis of sea ice motion. High-resolution Doppler frequency measurements are used to estimate the subsecond line-of-sight motion of ... -
High frequency copolymer ultrasonic transducer array of size-effective elements
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-05)A layer-by-layer deposition method for producing dual-layer ultrasonic transducers from piezoelectric copolymers has been developed. The method uses a combination of customized and standard processing to obtain 2D array transducers with electrical connection of the individual elements routed directly to the rear of the substrate. A numerical model was implemented to study basic parameters effecting ... -
Poleward energy transport: is the standard definition physically relevant at all time scales?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-17)Poleward energy transport in the atmosphere and oceans constitutes an important branch of the global energy budget, and its role in the climate system has been the subject of many studies. In the atmosphere, the transport is affected by “eddies” and large scale meridional cells, both with zero net mass transport across latitude circles, but also partly by processes associated with a net transport ... -
Accurate estimation of the illumination pattern’s orientation and wavelength in sinusoidal structured illumination microscopy
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-05)Structured illumination microscopy is able to improve the spatial resolution of wide-field fluorescence imaging by applying sinusoidal stripe pattern illumination to the sample. The corresponding computational image reconstruction requires precise knowledge of the pattern’s parameters, which are its phase (φ) and wave vector (<b>p</b>). Here, a computationally inexpensive method for estimation of ... -
On the theory of the incoherent scatter gyrolines
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-20)The incoherent scatter spectrum feature referred to as the “gyroline” is investigated theoretically and experimentally. The gyroline is associated with the dispersion relation for electrostatic whistler waves. Earlier treatments by Trulsen and Bj⊘rna (1978, and references therein) derive the frequency and growth rate for these waves, but their derivation is only accurate for very small magnetic ... -
GNSS Observations of Ionospheric Variations During the 21 August 2017 Solar Eclipse
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-20)On 21 August 2017, during daytime hours, a total solar eclipse with a narrow ∼160 km wide umbral shadow occurred across the continental United States. Totality was observed from the Oregon coast at ∼9:15 local standard time (LST) (17:20 UT) to the South Carolina coast at ∼13:27 LST (18:47 UT). A dense network of Global Navigation Satellite Systems (GNSS) receivers was utilized to produce total ... -
Determination of the Edge of Criticality in Echo State Networks Through Fisher Information Maximization
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03)It is a widely accepted fact that the computational capability of recurrent neural networks (RNNs) is maximized on the so-called “edge of criticality.” Once the network operates in this configuration, it performs efficiently on a specific application both in terms of: 1) low prediction error and 2) high shortterm memory capacity. Since the behavior of recurrent networks is strongly influenced by the ...