Mastergradsoppgaver i teknologi - anvendt fysikk: Nye registreringer

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    • Sensitivity analysis of Gaussian process machine learning for chlorophyll prediction from optical remote sensing 

      Blix, Katalin (Master thesis; Mastergradsoppgave, 2014-05-30)
      The machine learning method, Gaussian Process Regression (GPR), has lately been introduced for chlorophyll content mapping from remotely sensed data. It has been shown that GPR has outperformed other machine learning and empirical methods in accuracy, speed and stability. Moreover, GPR not only estimates the chlorophyll content, it also provides the certainty level of the prediction, allowing the ...

    • Design and experimental investigation of charge amplifiers for ultrasonic transducers 

      Hansen, Svein Kristian Esp (Master thesis; Mastergradsoppgave, 2014-06-02)
      Amplifiers are used in all types of electrical circuits to boost signal and there is a huge variety in designs used for different applications. For ultrasonic applications our group has previously used commercial available transimpedance amplifiers that converts a current to a voltage, but these amplifiers have a linear response over its frequency range. To preserve as much information as ...

    • Optical Trapping, Levitation and Tracking of Microparticles Using Waveguides 

      Helle, Øystein Ivar (Master thesis; Mastergradsoppgave, 2014-06-02)
      Microparticles are trapped by optical forces created by the evanescent field present on the surface of an optical waveguide. An optical waveguide loop with an intentional gap is used to propel and stably hold the trapped particles. The particles are trapped in the gap of the loop by counter-diverging fields. Simulations indicate that particles trapped in the gap on a strip waveguide will be levitated. ...

    • Investigating robot navigation in health care with the Giraff telepresence robot 

      Kåven, Ove Henrik (Master thesis; Mastergradsoppgave, 2013-10-29)
      The Norwegian public healthcare system will not have the manpower to care for the elderly at the same level as now, unless technological solutions are found to make the most of the available manpower. This thesis investigates potential technologies for allowing the Giraff, a telepresence robot, to navigate and patrol an eldercare center autonomously, thus letting caregivers save time when checking ...

    • Particle tracking in 3D 

      Brox, Petter (Master thesis; Mastergradsoppgave, 2013-06)
      The evanescent field of an optical waveguide can be used to trap and propel microscopic particles. A 1µm particle is trapped on a strip waveguide and propelled forward until it reaches a 10µm gap at the centre of a loop, created by splitting the waveguide into two branches. According to simulations, the particle will be elevated 3µm in the gap and be stably trapped in the middle of the gap. The goal ...

    • Comparing SAR measurments of natural oil seeps in the Gulf of Mexico with mineral and biological slicks in the North Sea 

      Hanssen, Claes Anders Storm (Master thesis; Mastergradsoppgave, 2013)
      In this thesis, natural oil seeps in Synthetic Aperture Radar (SAR) images are studied. The intension is to compare seeps to known oil slicks as emulsion-oil, crude-oil and plant-oil. TerraSAR-X and Radarsat-2 data with these di erent slicks are analyzed. Polarimetric features are extracted for all the scenes, histograms and scatterplots of values from the slicks are evaluated. Finally a ...

    • Experimental and numerical estimation of ultrasonic attenuation in polymers based on wave transmission methods 

      Grimstad, Trude (Master thesis; Mastergradsoppgave, 2013-07-01)
      PI-film, also known as Kapton, is a widely used polymer in the production of electronic equipment. Its use in printed circuit boards and sensors is increasing. It is therefore important to have knowledge about ultrasonic attenuation in the polymer. The main goal of this thesis was to investigate the attenuation of ultrasound through different polymers with different thicknesses. The presentation ...

    • Mean shift spectral clustering using kernel entropy component analysis 

      Agersborg, Jørgen Andreas (Master thesis; Mastergradsoppgave, 2012-06-01)
      Clustering is an unsupervised pattern recognition technique for finding natural groups in data, whether it is a grouping of web pages found by a search engine or segmenting satellite images into different types of ground cover. There exists a variety of different ways to perform clustering ranging from heuristics rules designed for a specific dataset to general procedures which can be applied to all ...

    • Information theoretic learning with K nearest neighbors : a new clustering algorithm 

      Vikjord, Vidar Vangen (Master thesis; Mastergradsoppgave, 2012-06-01)
      The machine learning field based on information theory has received a lot of attention in recent years. Through kernel estimation of the probability density functions, methods developed with information theoretic measures are able to use all the statistical information available in the data, not just a finite number of moments. However, by using kernel estimation, the methods are dependent on choosing ...

    • Semi-supervised Classification using Kernel Entropy Component Analysis and the LASSO. 

      Myhre, Jonas Nordhaug (Master thesis; Mastergradsoppgave, 2011-12-15)
      In this thesis we present a new semi-supervised classification technique based on the Kernel Entropy Component Analysis (KECA) transformation and the least absolute shrinkage selection operator (LASSO). The latter is a constrained version of the least squares classifier. Traditional supervised classification techniques only use a limited set of labeled data to train the classifier, thus leaving ...

    • 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 ...

    • Improved hardware stability and signal amplification in a medical microwave radiometer 

      Tobiassen, Alexander (Master thesis; Mastergradsoppgave, 2010-10-27)
      Breast cancer is one of the most frequent types of cancer in the female population today. Modern diagnostic modalities, while proven to be helpful within large scale screening programs, are inherently limited with regards to specificity and sensitivity, and use active methods for acquisition of information. A passive and non-invasive method for detection and diagnostic purposes could therefore be a ...

    • Time and temperature control of a camera 

      Kristiansen, Anders (Master thesis; Mastergradsoppgave, 2010-07-13)
      In scientific experiments there are an increasing usage of cameras, along with other instruments, to observe parameters of physical processes. In this thesis, we will discuss how a microcontroller (ATMEL ATmega 324 PA) can be used to control the operation temperature in a camera. It will be discussed why this control of temperature can be useful for the quality of the pictures. Since this thesis is ...

    • Design, implementering og evaluering av et trådløst medisinsk radiometer basert på IEEE 802.15.4-standarden og Zigbee. 

      Johansen, Amund Kronen (Master thesis; Mastergradsoppgave, 2009-06-01)
      Brystkreft er den vanligste kreftformen for kvinner og overlevelsesraten er betydelig høyere ved tidlig deteksjon. De vanligste undersøkelsesmetodene (mammografi, ultralyd, MRI) er basert på aktive metoder som medfører en viss strålingsfare. Et enkelt, ikke-invasivt instrument som baserer seg på passive metoder er derfor motivasjonen for denne masteroppgaven. Oppgaven beskriver en konseptuell ...

    • Optisk resonans i mikrokuler av glass med høy brytningsindeks 

      Husabø, Bjarne Janson (Master thesis; Mastergradsoppgave, 2009-06-15)
      I denne oppgaven har vi sett på effekten av lys som kobles fra en bølgeleder inn i optiske mikrokuler av høyindeksglass. Vi har studert Q-faktorer, og funnet at disse er lavere for kuler omgitt av vann enn tørre kuler, men at forskjellen er mindre enn mellom individuelle kuler. Vi har observert høyere ordens resonanser i kuler med større diameter. Vi har også forsøkt å utnytte resonans til å flytte ...

    • Monostatisk antennearray for UWB radar 

      Andersen, Rolf (Master thesis; Mastergradsoppgave, 2009-06)
      Ultrabredbåndet (ultrawideband - UWB) radar brukt til deteksjon av bryst-kreft viser oppløftende resultater på grunn av dens gode romlige oppløsning og dype penetreringsdybde. Bakgrunnen for å bruke UWB-radar til dette formålet er kontrasten mellom de dielektriske egenskapene til friskt brystvev og en kreftsvulst. Noe som vil føre til relativt mye reflektert energi fra kreftsvulsten. En av utfordringene ...

    • Estimering av dempingskoeffisienter i elastiske materialer ved hjelp av bredbåndet ultralyd 

      Ali, Josoph Abuker (Master thesis; Mastergradsoppgave, 2009-07-01)
      Dette er en eksperimentell oppgave der et bredbåndet ultralydsystem er brukt til å undersøke hvordan dempingen av ultralydbølger i elastiske materialer, avhenger av frekvensen. For å gjøre denne undersøkelsen ble det utviklet en holder i pleksiglass med en ultralydtransduser på hver side. I denne holderen kan prøver av ulike materialer lett festes og undersøkes ved at holderen plasseres i et vannbad. ...

    • Videoanalyse av termo-fluidale egenskaper til bolus for bruk innen hypertermisk behandling av brystkreft 

      Kvitberg, Jill-Iren Karlsen (Master thesis; Mastergradsoppgave, 2008-09-15)
      Varmeterapi (hypertermi) er en ny behandlingsmetode for krefttyper som ligger overfladisk plassert i kroppen. Prinsippet består i å varme opp vev til en temperatur på 42-45 ̊C, noe som øker raten for celledød i vevet. En multilags likeformet applikator er utviklet spesielt for dette formålet. En av bestanddelene i denne applikatoren er vannbolusen. Dens hensikt er å sørge for kontrollert temperatur ...

    • Information theoretic learning for pattern classification 

      Kvisle Storås, Ola (Master thesis; Mastergradsoppgave, 2007-12-17)
      This thesis is a study of pattern classification based on information theoretic criteria. Information theoretic criteria are important measures based on entropy and divergence between data distributions. First, the basic concepts of pattern classification with the well known Bayes classification rule as a starting point is discussed. We discuss how the Parzen window estimator may be used to ...

    • Tidsreversert fokusering av ultralyd i sylindriske bølgeledere 

      Færsnes, Torjus (Master thesis; Mastergradsoppgave, 2008-06)
      I denne oppgaven ser vi nærmere på fenomenet tidsreversert fokusering som kan benyttes til å fokusere et signal i tid og rom. Mulighetene for tidsreversering er mange og prinsippet kan benyttes generelt ved overføring av både akustiske, elektromagnetiske og andre bølgeformer, der det er liten dempning av signalet under overføringen. I korthet går tidsreversering ut på å få en bølge som går fra et ...