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Browsing Fakultet for naturvitenskap og teknologi by Title
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Thorstensen, Lene (Master thesis; Mastergradsoppgave, May-2011)[+][-]
Abstract: Feltarbeid og analyser av batymetriske-, seismiske- og gravimetriske data er sammenstilt for å korrelere tektoniske elementer i ytre del av Senja og Kvaløya i Troms. Berggrunnen i kystområdene på nordøstlige Senja og Kvaløya i Troms tilhører Vest-Troms gneis region og består av neoarkeiske og paleoproterozoiske tonalittisk gneis og mafiske intrusiver (Kattfjordkomplekset), samt metasuprakrustale og metavulkanske bergarter (Torsnes- og Astridalbelte). Foliasjonen stryker NV-SØ og endrer orientering til VNV-ØSØ og er definert som F3 folder. Endring i foliasjonens fall er definert som F2 folder og kartlagt over hele studieområdet. Foldingen av de prekambriske bergartene er ansett som et resultat av polyfase folding i forbindelse med svekofennisk deformasjon. NV-SØ strykende strukturer på land definert som duktile skjærsoner og kan følges på den grunnedelen av batymetrien og er styrt av den prekambriske hovedtrenden. Det antas at også at de NV-SØ strykende forkastningene i de dypere delene også er strukturstyrte og faller sammen med Senjabruddsone. Mesozoiske sprø forkastninger og sprekker stryker NØ-SV til NNØ-SSV og er hovedsakelig foliasjons kuttende. Lokalt opptrer sprøforkastninger subparallelt til den prekambriske foliasjonen det vil si i hengselsonen til regionale F3 folder. Forkastningene på land er relatert til det NØ-SV strykende Vestfjord-Vanna forkastnings kompleks. Undersøkelser av seismiske data viser en dominerende forkastnings trend som stryker NØ-SV til NNØ-SSV og er relatert til Troms Finnmark Forkastnings Komplekset. URI: http://hdl.handle.net/10037/3416 File(s) in this item: 1
thesis.pdf (13.20Mb) -
Kube, Ralph; Garcia, Odd Erik; LaBombard, Brian; Terry, James L.; Zweben, Stewart (Conference object; Konferansebidrag, 2012)[+][-]
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Zeigler, Harald Bergersen (Master thesis; Mastergradsoppgave, 02-Jun-2008)[+][-]
Abstract: The theme for the master thesis is simulation of homogeneous, isotropic turbulence. I have shown that the energy of the velocity field is decaying in time, but the comparison to the reference solution is however invalid, due to the fact that the reference solution may have scalings that are not obvious to the observer, and that my own simulation results seemed to behave quite strange, with a sudden fall of energy in the first time-steps, which I have no explanation for why happened. The thesis consists of a rather large theory section and a smaller discussion in the end. Chapters 3 and 4 are mainly introductory and addressing the theme and job description. They also serve as mild introductions to tuirbulence theory as well as mathematical, numerical subjects. Overall, the reader is assumed not to be very familiar with mathematical terms, applied mathematics and physics, so many terms are explained. The provided theory is designed to teach a reader totally unfamiliar with science some things, but not all. The author has not forgot about the experienced reader who may be an expert in the field, and the level of the thesis should be high enough for that person also to maintain interest while reading. URI: http://hdl.handle.net/10037/1642 File(s) in this item: 1
thesis.pdf (653.3Kb) -
Rydningen, Tom Arne; Vorren, Tore Ola (Conference object; Konferansebidrag, 2011)[+][-]
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Sanchez Borque, Jorge (Master thesis; Mastergradsoppgave, May-2009)[+][-]
Abstract: The aim of this master thesis has been to interpret the Late Cenozoic paleo-environments and the sedimentary processes in the Veslemøy High area, southwestern Barents Sea. Six seismic units and eight seismic unconformities, including the seafloor, are identified in the study area and correlated with previous work in the Sørvestnaget Basin. Submarine channels with a downslope (E-W) orientation suggest a glacimarine environment, i.e. the channels are inferred to have been formed by turbidity currents originating from glacial meltwater on the deepest reflector. On shallower reflectors, megascale glacial lineations, ridges and parts of hill-hole pairs indicate that grounded ice reached the paleo-shelf edge at least six times in the last 1.5 Ma. Moreover, two of the shallower seismic units show indications of sediment blocks that are inferred to have been subglacially eroded, transported and deposited by ice streams. The influence of the ice stream flowing from the Bjørnøyrenna in the last 330 ka is evident in the Veslemøy High; however, the origin of the ice streams is unclear on older paleo-surfaces. URI: http://hdl.handle.net/10037/1911 File(s) in this item: 1
thesis.pdf (11.38Mb) -
Sørensen, Steffen Aagaard (Doctoral thesis; Doktorgradsavhandling, 22-Mar-2011)[+][-]
Abstract: The overall objective for this PhD-study was to further advance the understanding of the oceanographic variability and development in the Nordic Seas during the Late Glacial and the Holocene and towards the present. The focus is specifically on the poleward Atlantic Water advection along the continental margins of Norway, into the SW Barents Sea and along the West Spitsbergen slope. Four high resolution sediment cores retrieved from northern continental shelve allowed examination of spatial and temporal oceanographic and environmental variability and elucidation of underlying forcing mechanisms. The sediment cores were investigated using several paleoceanographic proxies. These include planktic and benthic foraminiferal fauna distributions, measurements of stable isotopes (δ18O, δ13C) on foraminiferal tests and transfer function SST reconstructions based on planktic foraminifer species counts. Grain size analysis, IRD counts, clay mineral analysis and chemical analysis of bulk sediment carbon content were also used. Additionally the relatively new paleothermometer, the Mg/Ca-ratio, was applied on planktic and benthic foraminifera to test and examine its applicability in Subarctic and Arctic environmental settings. The Mg/Ca-ratios were used to constrain reconstructions of sea surface and bottom water temperatures. Furthermore, Mg/Ca-ratios combined with isotopic measurements performed on the same foraminiferal species were used for quantization of past oceanic salinity changes. Weak Atlantic Water influence was observed briefly at around 18,700 and after 15,000 cal yr B.P. in the SW Barents Sea indicating an early deglaciation of Ingøydjupet. Sub surface Atlantic Water inflow was observed from the beginning of the records (at 14,000 cal yr B.P.) in both the eastern Fram Strait and in Andfjorden. Atlantic Water influx was diminished during the Younger Dryas at all investigated core sites. Strong inflow of Atlantic Water resulted in emergence at the surface during the glacial – interglacial transition. The emergence had a south-north time delay of ca. 1,000 years which probably can be ascribed to increasing influence from a lingering pool of sea-ice and melt water towards the north. Reconstructed temperatures of Atlantic Water entering the Arctic Ocean through the eastern Fram Strait show a ~2°C warming during the last ca. 100 years. This warming is unprecedented over the past 2000 years and is probably linked to the Arctic amplification of global warming. Description: Papers 1, 2 and 5 are not available in Munin due to publishers' restrictions:
1. S. Aagaard-Sørensen, K. Husum, M. Hald, J. Knies: 'Paleoceanographic development in the SW Barents Sea during the Late WeichselianeEarly Holocene transition',Quaternary Science Reviews 29 (2010) 3442-3456. Paper available at http://dx.doi.org/10.1016/j.quascirev.2010.08.014
2. J. Junttila, S. Aagaard-Sørensen, K. Husum and M. Hald: 'Late Glacial–Holocene clay minerals elucidating glacial history in the SW Barents Sea', Marine Geology 276 (2010) 71–85. Paper available at http://dx.doi.org/10.1016/j.margeo.2010.07.009
5. Spielhagen, R. F.,Werner, K., Aagaard-Sørensen, S., Zamelczyk, K., Kandiano,E., Budeus, G., Husum, K., Marchitto, T. and Hald, M.:'Enhanced Modern Heat Transfer to the Arctic by Warm Atlantic Water', SCIENCE(2011), 331, 450-453. Paper available at http://dx.doi.org/10.1126/science.119739URI: http://hdl.handle.net/10037/3007 File(s) in this item: 3
paper_3.pdf (1.151Mb)paper_4.pdf (2.138Mb)thesis.pdf (818.7Kb) -
Baeten, Nicole Jeanne (Master thesis; Mastergradsoppgave, Nov-2007)[+][-]
Abstract: Three sediment cores, swath multibeam bathymetry data and high-resolution seismic data from Billefjorden, Svalbard have been analysed for a better understanding of the Late Weichselian and Holocene glacier activity as well as sedimentary process and glacigenic deposits in the fjord. The data reveal that glacial linear features were generated in the central part of Billefjorden while it was filled with ice draining the Svalbard-Barents Sea ice sheet during the Last Glacial. A till in the bottom of a sediment core from the central part of the fjord is inferred to have been deposited before the ice front retreated into Billefjorden around 11230 cal. years BP. An overlying glacimarine unit deposited between c. 11230 and 11200 cal. years BP indicates that the glacier retreated from central parts of the fjord to the fjord head in approximately 30 years. Annual recessional moraines deposited during this period suggest that the glacier front retreated approximately 330 m/ year at the end of the last Glacial. High concentration of shells, low amounts of IRD and XRD results indicate a Holocene climatic optimum between c. 11200 – 7930 cal. years BP in which Nordenskiöldbreen was most likely much smaller than it is at present. XRD results and comparatively high amounts of IRD point to a complex pattern of ice rafting between c. 7930 and 3230 cal. BP. IRD deposited before c. 5470 cal. years BP was most likely transported by sea ice, whereas IRD after 5470 cal. years points towards a growth of Nordenskiöldbreen. The time after c. 3230 is mainly characterised by suppressed rafting of sea ice and icebergs because of the possible presence of multi-year shorefast sea ice during the Neoglacial maximum. Glacial lineations on a bedrock terrace in the inner fjord were formed during a Neoglacial advance of Nordenskiöldbreen. Iceberg ploughmarks and recessional moraines were most likely generated during the retreat after the maximum Neoglacial extent of Nordenskiöldbreen. Mass-transport activity in Billefjorden probably occurred throughout the entire Holocene. There might haven been an increased mass-transport activity shortly after the deglaciation of the fjord, because high rates of isostatic uplift might have caused seismic activity. Other triggering mechanisms include the development of oversteepened slopes by high sediment supply and the pushing of sediments at the grounding line of the glacier. Pockmarks in the central part of the fjord were most likely generated by the seepage of thermogenic gas along the Billefjorden fault zone. URI: http://hdl.handle.net/10037/1274 File(s) in this item: 1
Thesis.pdf (42.43Mb) -
Jore, Inge Håvard (Master thesis; Mastergradsoppgave, 01-Jun-2010)[+][-]
Abstract: Dei siste åra har fleire internasjonale undersøkjingar som TIMSS og PISA vist at norske elever har dårlige realfagsprestasjoner. Fleire tiltak har vorte sett i gang for å betre dette, eitt av dei er eit auka fokus på vitensenter. Vitensenter er eit populærvitenskapeleg opplevings- og læringssenter innanfor matematikk, naturvitenskap og teknologi der dei besøkande lærer ved å eksperimentere sjølv. Oppgåva handler om kva utbytte elever sjølv opplever ved eit besøk på vitensenter, og på kva måte dei ønsker å lære. Den tar opp kva eit vitensenter kan bidra med inn imot naturfagundervisninga, og utfordringer som er med eit besøk på vitensenter. URI: http://hdl.handle.net/10037/2623 File(s) in this item: 1
thesis.pdf (1.130Mb) -
Dahl, Olav Erik (Master thesis; Mastergradsoppgave, 15-May-2008)[+][-]
Abstract: Gjennom dei siste tiåra har norsk skule vore gjennom fleire omfattande reformer. Trass dette ser ein at norsk skule ikkje presterar særleg høgt i internasjonale undersøkingar når det gjeld ferdigheiter i matematikk. Ein ser derimot at asiatiske land presterar langt høgare. Denne oppgåva tar for seg ein japanske kompetanseutviklingsmodell kalla lesson study. Denne modellen blir gitt ein del av æra for at den japanske skulen er som den er. Modellen handlar om at fleire lærarar går ilag for å utvile si eiga undervising. Dette vert gjort gjennom felles planlegging, undervising med observasjon og diskusjon i ettertid. Deltakarane som utfører lesson study i oppgåva er ein student på praktisk pedagogisk utdanning, ein lærar ved ein vidaregåande skule, ein rettleiar frå Universitet og underteikna. Vekstfaktor var det matematiske temaet som la grunnlaget for forskingstimen. Oppgåva er eit case-studium av denne lesson study, og prøver å belyse korleis lesson study kan vere med å utvikle og forbetre matematikkundervisinga i norske klasserom. URI: http://hdl.handle.net/10037/1498 File(s) in this item: 1
thesis.pdf (572.6Kb) -
Lundamo, Trine (Master thesis; Mastergradsoppgave, 15-Feb-2008)[+][-]
Abstract: Waves that are reflected and refracted by material bodies also transfer momentum to these bodies. This means that the wave field induces a force on the bodies, and multiple reflections between bodies induce forces between them. Light is an electromagnetic wave phenomenon, and the waves carry energy and momentum. Hence, any object that is scattering and refracting light is also acted upon by a light induced force. This force is a tiny force and is usually ignored, but if the objects are small enough the force induced by the light field would dominate all other forces. Due to this it is possible to manipulate small objects using light from a laser. This thesis is based on an experiment on optical binding of two dielectric spheres, where the spheres were small enough to make the force induced by the light field the dominating force. In the experiment bistability and hysteresis in the equilibrium separations of the optically bound dielectric spheres were observed in one dimension. In this thesis the experiment will be modeled with a simplified setup, and the goal is to see if it is possible to find bistability in two dimensions also. Numerical approximations are used to calculate the wave field, and from this the force on the objects can be found. Description: Appendix A to D have been removed from the published pdf at the request of the author. URI: http://hdl.handle.net/10037/1395 File(s) in this item: 1
thesis.pdf (7.947Mb) -
Berget, Ingeborg Katrin (Master thesis; Mastergradsoppgave, 01-Jun-2010)[+][-]
Abstract: Likningar er eit tema innanfor matematikkfaget som mange elevar synest er vanskeleg. I denne studien har eg prøvd å sjå nærare på elevar si forståing av likningar, og har gjort ein kvalitativ studie mellom elevar på fyrste året i vidaregåande skule. Eg gjennomførte ei undersøkning der elevane skulle løyse oppstilte likningar og svare på spørsmål som gjekk på forståing av likningar. Problemstillinga mi var ”Kva veit dei som forstår, om likningar?”. Eg drøfta kva dei som forstår veit, og kva dei andre ikkje veit. Det verka som om mange elevar har pugga framgangsmåtar for å løyse likningar, men at dei ikkje skjønar eller tenker over matematikken bak det dei gjer. Dei som forstår, kan truleg lettare lausrive seg frå faste prosedyrar og nytte kreativitet i matematikkfaget. URI: http://hdl.handle.net/10037/2640 File(s) in this item: 1
thesis.pdf (1.063Mb) -
Goldberg, Vladislav V.; Lychagin, Valentin V.; Akivis, Maks A. (Journal article; Tidsskriftartikkel; Peer reviewed, 31-Mar-2004)[+][-]
Abstract: We find d − 2 relative differential invariants for a d-web, d ≥ 4, on a two-dimensional manifold and prove that their vanishing is necessary and sufficient for a d-web to be linearizable. If one writes the above invariants in terms of web functions f(x, y) and g4(x, y), ..., gd(x, y), then necessary and sufficient conditions for the linearizabilty of a d-web are two PDEs of the fourth order with respect to f and g4, and d − 4 PDEs of the second order with respect to f and g4, ..., gd. For d = 4, this result confirms Blaschke’s conjecture on the nature of conditions for the linearizabilty of a 4-web. We also give Mathematica codes for testing 4- and d-webs (d > 4) for linearizability and examples of their usage. Description: Dette er forfatternes aksepterte versjon. URI: http://hdl.handle.net/10037/2056 File(s) in this item: 1
article.pdf (205.7Kb) -
Lindell, Kristoffer; Fahlgren, Anna; Hjerde, Erik; Willassen, Nils Peder; Fällman, Maria; Milton, Debra L (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: Colonization of host tissues is a first step taken by many pathogens during the initial stages of infection. Despite the impact of bacterial disease on wild and farmed fish, only a few direct studies have characterized bacterial factors required for colonization of fish tissues. In this study, using live-cell and confocal microscopy, rainbow trout skin epithelial cells, the main structural component of the skin epidermis, were demonstrated to phagocytize bacteria. Mutant analyses showed that the fish pathogen Vibrio anguillarum required the lipopolysaccharide O-antigen to evade phagocytosis and that O-antigen transport required the putative wzm-wzt-wbhA operon, which encodes two ABC polysaccharide transporter proteins and a methyltransferase. Pretreatment of the epithelial cells with mannose prevented phagocytosis of V. anguillarum suggesting that a mannose receptor is involved in the uptake process. In addition, the O-antigen transport mutants could not colonize the skin but they did colonize the intestines of rainbow trout. The O-antigen polysaccharides were also shown to aid resistance to the antimicrobial factors, lysozyme and polymyxin B. In summary, rainbow trout skin epithelial cells play a role in the fish innate immunity by clearing bacteria from the skin epidermis. In defense, V. anguillarum utilizes O-antigen polysaccharides to evade phagocytosis by the epithelial cells allowing it to colonize rapidly fish skin tissues. URI: http://hdl.handle.net/10037/4914 File(s) in this item: 1
article.pdf (1.446Mb) -
Gustad, Christian O'cadiz (Master thesis; Mastergradsoppgave, May-2010)[+][-]
Abstract: In the thesis the local classification of 2-dimensional solvable Lie algebra action on the plane is given. Normal forms of such actions are found. The classification applied to classifcation of 2nd order differential equations that are solvable in quadratures. URI: http://hdl.handle.net/10037/4371 File(s) in this item: 1
thesis.pdf (573.6Kb) -
Aslaksen, Torsten; Shiokawa, K.; Ieda, A.; Nakajima, A.; Sakaguchi, K.; Nomura, R.; Greffen, M.; Spanswick, E.; Donovan, E.; Mende, S. B.; McFadden, J.; Glassmeier, K. H.; Angelopoulos, V.; Miyashita, Y. (Journal article; Tidsskriftartikkel; Peer reviewed, 2009)[+][-]
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Zivkovic, Tatjana; Rypdal, Kristoffer (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
Abstract: The storm index SYM-H, the solar wind velocity v, and interplanetary magnetic field Bz show no signatures of low-dimensional dynamics in quiet periods, but tests for determinism in the time series indicate that SYM-H exhibits a significant low-dimensional component during storm time, suggesting that self-organization takes place during magnetic storms. Even though our analysis yields no discernible change in determinism during magnetic storms for the solar wind parameters, there are significant enhancement of the predictability and exponents measuring persistence. Thus, magnetic storms are typically preceded by an increase in the persistence of the solar wind dynamics, and this increase is also present in the magnetospheric response to the solar wind. Description: This article is part of Tatjana Živkovics' doctoral thesis. Available in Munin at http://hdl.handle.net/10037/3231 URI: http://hdl.handle.net/10037/4643 File(s) in this item: 1
article.pdf (1.766Mb) -
Johansen, Jarle Andre (Doctoral thesis; Doktorgradsavhandling, 03-Jun-2004)[+][-]
Abstract: The main topic of this thesis is experimental low-frequency electrical noise characterization of semiconductor devices. In particular, we concentrate on applications of the silicon-germanium alloy (SiGe). Low-frequency electrical noise is a sensitive measure of defects and non-idealities in semiconductor devices, which directly or indirectly impact device performance and reliability. Thus, it is of prime importance to be able to characterize the noise in semiconductor devices. We compare the low-frequency noise from poly-crystalline silicon-germanium thin film resistors with different germanium content, film thickness and doping level. The noise level decreases with increasing doping density. We find that the germanium content and film thickness have little influence on the noise level. The noise was found to stem from mobility fluctuations in the depletion region of the grains. We compare the low-frequency noise of silicon based field-effect transistors with poly-crystalline gates, made from silicon and silicon-germanium. The output noise level for N-MOSFETs is independent of the gate material, whereas for P-MOSFETs the silicon-germanium gate material results in lower noise. Analysis of fluctuating physical quantities, points towards mobility fluctuations for P-MOS, and number fluctuations for N-MOS. We present results from measurement of the low-frequency electrical noise in Al- GaInP QuantumWell Lasers. Experimental evidence of a connection between the noise and device reliability is found, and hence, low-frequency noise measurements can be used as a non-destructive reliability indicator for laser diodes. The low-frequency noise in state-of-the-art silicon-germanium Heterojunction Bipolar Transistors (HBTs) is explored. Device geometrical down-scaling induces a deviceto- device noise variation, caused by small sets of noise generating traps, that are different from device to device. We use proton irradiation to introduce additional traps, and find that it can reduce the noise variation without increasing the noise level significantly. Aggressive down-scaling normally results in higher low-frequency noise. However, we find that the latest generation of SiGe HBTs (> 200 GHz) breaks this trend, and only a residual background noise remains, resulting in record values of low-frequency noise level and noise corner frequency. We present, and apply, recent statistical tools to probe for non-linear coupling between frequency components in a noise signal. These tools are applied to low-frequency noise time series with Random Telegraph Signal (RTS) noise from small geometry SiGe HBTs. The noise in small HBTs is shown to be non-Gaussian and non-linear. The nonlinearity is shown to originate from the RTS component of the noise. URI: http://hdl.handle.net/10037/345 File(s) in this item: 1
thesis.pdf (2.912Mb) -
Qi, Peng (Master thesis; Mastergradsoppgave, 06-Jun-2006)[+][-]
Abstract: The main purposes of this thesis are the Low-Frequency Noise measurement of Silicon-Germanium Heterojunction Bipolar Transistors and its Power Spectrum Density Characterizing. The new generation 375 GHZ SiGe HBTs were measured in this work. We show that most of PSDs of the new generation SiGe HBTs have very ”bumpy” spectra which is contributed by GR noise sources. We investigated their basic characteristics of LFN such as the dominant noise source, base-current dependence, emitter geometrical scaling dependence and noise variation. They have similar LFN characteristic with the elder generation SiGe HBTs except for the emitter geometrical dependence. The most important contribution of this work is that we particularly focused on developing a totally automatic mechanism to fit the Low-Frequency Noise Power Spectrum Density of SiGe HBTs so that we can use the magnitude of the fitting curve as the low-frequency noise level at any frequency. A model based predictive and autonomous method was engaged for this purpose. This method offers the possibility that we can automatically predict the noise sources of transistors to get good initial fitting parameters in advance instead of finding each of them by eyes. Experiments with the fitting method shows that: Always good fitting for most of the cases; Accurately locating each noise source; Sometimes meaningless fitting parameters but still good fitting. Therefore, by using this method, we can find out how each noise source acts on the spectrum, which noise source dominates the spectrum, etc. And some careful interpretations will be presented based on this fitting procedure. Further, this method still leaves large space to be extended, so it is a good basis for future work on fitting. URI: http://hdl.handle.net/10037/237 File(s) in this item: 1
thesis.pdf (4.312Mb) -
Aarbakke, Anne Staurland (Master thesis; Mastergradsoppgave, 01-May-2007)[+][-]
Abstract: Images are commonly used on a daily basis for research, information and entertainment. The introduction of digital cameras and especially the incorporation of cameras in mobile phones makes people able to snap photos almost everywhere at any time since their mobile phone is almost always brought with them. The fast evolution in hardware enables users to store large image collection without high costs. Making use of these image collections requires efficient image retrieval techniques. Traditional image retrieval techniques like text-based image retrieval and content-based image retrieval techniques have shortcomings. New techniques or combination of existing techniques must be established to provide users with adequate image retrieval functionality. This thesis describes two systems enabling users to retrieve information such as images, textual information, WAP-links or videos using SMS or MMS. One of the services, M2S is meant for tourists to retrieve information about attractions in Lofoten. M2S uses content-based image retrieval to retrieve the information requested. This service is designed and implemented in cooperation with Telenor R&I. The other system, CAIR is meant for users who want to retrieve images from an image collection using SMS. CAIR uses a context-based image retrieval to retrieve images. This system is designed, but not yet implemented. URI: http://hdl.handle.net/10037/1141 File(s) in this item: 1
thesis.pdf (2.161Mb) -
Skrunes, Stine (Master thesis; Mastergradsoppgave, Feb-2011)[+][-]
Abstract: In this thesis, marine targets in Synthetic Aperture Radar (SAR) imagery are studied. The appearance of different marine targets in different polarization channels, their scattering behaviour, and their contrast measures and geometric properties are investigated. RADARSAT-2 data containing ships, oil rigs and icebergs in ocean and/or sea ice background are evaluated. To be able to detect a target in a SAR image, a significant contrast between target and background is needed. In this thesis, peak-to-background ratios (PBR) and target-to-background ratios (TBR) are used to evaluate the contrasts for different target types and background classes. The relations between contrast measures and incidence angle, target size and weather conditions are addressed. In order to track, identify or classify targets, reasonable features for discrimination must be chosen. In this project, Hu's 1st geometric moment is used as a geometric feature to investigate the elongatedness of the targets. It is found that cross-polarization (HV and VH) gives better contrast than co-polarization (HH and VV), especially at low incidence angles. Where quad-polarimetric data is available, enhanced contrast can be obtained through polarimetric decompositions. For man-made targets, the contrasts are seen to be dominated by the volume scattering and double bounce components, i.e. HV+VH and HH-VV. For man-made targets in ocean, contrasts for co-polarization channels are seen to increase with incidence angle, while cross-polarization contrasts decrease. The contrast measures are also seen to increase with target size, and to decrease with increased wind in the case of ocean background. Comparison of contrasts for different target types shows that PBR is larger for man-made targets in sea ice than in ocean areas, while the opposite is seen for TBR. Comparison of man-made targets versus icebergs shows that the latter has highest mean PBR while man-made targets have highest mean TBR. Ships in sea ice have higher contrasts than icebergs in both PBR and TBR. More data would provide more reliable results and a more accurate comparison. It is seen that Hu's 1st moment may be a useful feature for distinguishing between small and large ships, or between larger ships and other target types. URI: http://hdl.handle.net/10037/3358 File(s) in this item: 1
thesis.pdf (27.55Mb)
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