The main focus of this master thesis work has been to image InAs emph{quantum dots} (QDs) using emph{atomic force microscopy} (AFM), to identify and evaluate various image processing methods used to estimate the volume of the InAs QDs. The InAs QDs studied in this thesis work, had been deposited on GaAs substrates, using solid-source emph{molecular beam epitaxy} (MBE) before the thesis work started. The total QD volume was determined for all samples, using eight different estimation methods. The purpose of estimating the total QD volume, was to compare the total volume to the deposited volume.Previous studies on similar samples, have indicated that the total volume can be larger than the deposited volume during MBE growth. This discrepancy is explained by incorporation of Ga from the substrate during growth. This was not observed in this thesis work. One possible explanation is that the samples have oxidized; resulting in a lower measured height.In addition, the relationship between atomic steps, defects and the appearance of large QDs were studied. parTwo series of samples were studied: one in which the QD growth temperature was varied and one in which the amount of deposited InAs was varied. The total QD volumes were found to increase with the QD growth temperature and the deposited InAs thickness. Square-shaped defects and contours of 2D islands were observed in nearly all samples. Higher/multiple terraces seem to be related to regions of higher QD density.

This thesis investigates the electrodeposition process of zinc-, copper-, silver-, and silver copperoxides at cathodic and anodic voltages. Silver copper oxide has been successfully electrodepositedon a substrate of PtSi from a pH 12 dilute solution of copper nitrate, silver nitrate and sodiumhydroxide at 0.9V vs a silver metal cathode. This film was confirmed to be polycrystalline AgCuO2by EDS and XRD studies. Zinc oxide and copper oxide were deposited on gold substrates from their respective nitrates. The zinc oxide deposition was confirmed polycrystalline in XRD and had a band gap between 3.2eV and 3.5eV measured by optical reflectance. The copper oxide appeared polycrystalline in SEM but only amorphous signal was achieved in XRD, the material had a band gap of around 2eV. Despite many attempts, clean silver oxide was not successfully deposited. These materials may all be suitable for solar cells applications.

In this thesis, clean and oxidized Pd(57)Cu(43)(100) single crystal surfaces were studied by LEED, STM and XPS in UHV conditions. The clean sample annealed to 300 degrees C has been found to either consist of ordered domains of Pd or Cu atoms forming a c(2 × 2) structure, or by a more disordered alloy c(2 × 2) structure of p4g symmetry. Small areas of (1 × 1) structure as well as screw dislocations and island- like formations are present on this surface. Annealing the clean sample to 600 degrees C causes Cu segregation to the surface as well as a shift towards higher binding energy of Pd 3d(5/2) core levels, and an almost defect- free surface with p(2 × 2) structure is seen. Oxidation at 300 degrees C of the surface annealed to 300 degrees C shows that a c(2 × 2) covers the whole surface for all oxygen dosages at 68L or above, and XPS spectra do not vary with oxygen dosage, hence the c(2 × 2) is inert in this case. For dosages of 1350L or above, oxide islands and a large number of defects could appear, depending on the preparation history of the sample. Oxidation at 300 degrees C and 600 degrees C of the Cu rich surface annealed to 600 degrees C reveals up to seven structures, which are p(2 × 2), c(2 × 2), (4 × 4)- like, hexagonal, maze- like, (2root(2) ×root(2))R45degrees missing row type and one more structure that could not be characterized. There is evidence that copper oxide phases are formed for the Cu rich surfaces annealed to 600 degrees C, but no bulk oxide was formed in any experiments. A detailed understanding of clean and oxidized Pd(57)Cu(43)(100) has been obtained at the atomic scale.

Vanntrevekst er den viktigste årsaken til aldring i polymerisk isolasjon i mellomspenningskabler. Sia vanntrær ikke dannes ved lav relativ fuktighet (R.H.), er det viktig å holde relativ fuktighet i isolasjonen lav så lenge som mulig. Dette kan gjøres ved å beskytte isolasjonen med ei kappe av to polymerer. For å beregne vanntransporten inn i isolasjonen, må kappematerialenes vanntransportegenskaper kjennes. For noen polymerer varierer vanntransportegenskapene med det hydrostatiske trykket og den relative fuktigheta (damptrykket). I denne oppgaven er det målt transportkoeffisienter for to kandidater til kappematerialer: én halvledende lineær lavdensitetspolyetylen (LLDPE) og én halvledende eterbasert termoplastisk polyuretan (TPU). Noen av prøvene har vært utsatt for strekking til 10 % statisk forlengelse og etterfølgende relaksasjon i forkant av forsøkene, for å finne ut om ei slik mekanisk påkjenning har noe å si for transportkoeffisientene. Det er gjort målinger av metningskonsentrasjoner ved 0,1 MPa og 30 MPa hydrostatisk trykk, og permeabilitetsmålinger ved forskjellige damptrykk. Konklusjonene om metningskonsentrasjonen i TPU ved 0,1 MPa og 30 MPa hydrostatisk trykk trekkes delvis på grunnlag av et tidligere arbeid. I tillegg har diffusjons- og løselighetskoeffisientene for ustrukket TPU blitt målt ved forskjellige damptrykk. Det er ikke funnet noen signifikant sammenheng mellom det hydrostatiske trykket og vannopptaket i noen av materialene, hverken med strukkede eller ustrukkede prøver. Det er heller ikke funnet at strekking har noen signifikant innvirkning på transportkoeffisientene, bortsett fra at strukket TPU viser en ca. 15 % større metningskonsentrasjon enn ustrukket TPU. Det er funnet at transportkoeffisientene i TPU varierer med damptrykket, men hverken diffusjons-, løselighets- eller permeabilitetskoeffisienten varierer mer enn med en faktor 3 mellom 20 % R.H. og 80 % R.H. For LLDPE er det ikke gjort like omfattende undersøkelser, men permeabilitetskoeffisienten i det materialet viser ingen damptrykkavhengighet.

<p>This paper investigates the solution of the free rigid body equations of motion, as well as of the equations governing the torqued rigid body. We will consider two semi-exact methods for the solution of the free rigid body equations, and we discuss the use of both rotation matrices and quaternions to describe the motion of the body; our focus is on the quaternion formulation. The approach to which we give the most attention is based on the Magnus series expansion, and we derive numerical methods of order 2, 4, 6, and 8, which are optimal as they require a minimal number of commutators. The other approach uses Gaussian quadrature to approximate an elliptic integral of the third kind. Both methods rely on the exact solution of the Euler equation which involves the exact computation of the elliptic integral of the first kind. For the solution of the torqued rigid body equations, we divide the equations into two systems where one of them is the free rigid body equations; the solutions of these two systems are then combined in the Störmer-Verlet splitting scheme. We use these methods to solve the so-called marine vessel equations. Our numerical experiments suggest that the methods we present are robust and accurate numerical integrators of both the free and the torqued rigid body.</p>

<p>In kernel density estimation, the most crucial step is to select a proper bandwidth (smoothing parameter). There are two conceptually different approaches to this problem: a subjective and an objective approach. In this report, we only consider the objective approach, which is based upon minimizing an error, defined by an error criterion. The most common objective bandwidth selection method is to minimize some squared error expression, but this method is not without its critics. This approach is said to not perform satisfactory in the tail(s) of the density, and to put too much weight on observations close to the mode(s) of the density. An approach which minimizes an absolute error expression, is thought to be without these drawbacks. We will provide a new explicit formula for the mean integrated absolute error. The optimal mean integrated absolute error bandwidth will be compared to the optimal mean integrated squared error bandwidth. We will argue that these two bandwidths are essentially equal. In addition, we study data-driven bandwidth selection, and we will propose a new data-driven bandwidth selector. Our new bandwidth selector has promising behavior with respect to the visual error criterion, especially in the cases of limited sample sizes.</p>

<p>In this master thesis we have presented a security analysis of the TLS protocol with particular emphasis on the recently discovered renegotiation attack. From our security proof we get that the Handshake protocol with renegotiation, including the fix from IETF, is secure, and hence not vulnerable to the renegotiation attack anymore. We have also analysed the Handshake protocol with session resumption, and the Application data protocol together with the Record protocol. Both of these protocols were deemed secure as well. All the security proofs are based on the UC (Universal Composability) security framework.</p>

<p>In the last years, there has been done research in using topology as a new tool for studying data sets, typically high dimensional data. These studies have brought new methods for qualitative analysis, simplification, and visualization of high dimensional data sets. One good example, where these methods are useful, is in the study of microarray data (DNA data). To be able to use these methods, one needs to acquire knowledge of different topics in topology. In this paper we introduce simplicial homology, persistent homology, Mapper, and some simplicial complex constructions.</p>

<p>A priority based rule for use during the process of scheduling trains oper- ating on a single track railway line was proposed by the Norwegian railway operator and owner, Jernbaneverket. The purpose of this study is to inves- tigate the effect of the suggested scheduling rule on the scheduled waiting times suffered by trains operating on a segment of the railway line. It is shown that the scheduling rule, under certain limiting assumptions, can be studied in the setting of queuing theory and that it has properties in common with a theoretical priority discipline combining two well docu- mented priority rules. The main part of this study is the development and analysis of a threshold based, combined preemptive/non-preemptive priority discipline. Under the combined discipline, preemptions are allowed during the early stage of processing only. Theoretical expressions for flow-times of jobs passing through the queuing system are reached through detailed studies of the non-preemptive and the preemptive priority discipline. The relationship between the suggested priority based scheduling rule and the theoretical, combined priority discipline is finally illustrated by sim- ulations. When adjusted for actual time spent by trains on traversing the line segment, the steady state solution for flow-times obtained from queuing theory yields an accurate expression for the trains’ average scheduled wait- ing times. The scheduling problem can in fact be modeled accurately by an M/G/1 queue under the combined priority discipline.</p>

<p>In this thesis I have studied how to estimate parameters in an extreme value model with Markov Chain Monte Carlo (MCMC) given a data set. This is done with synthetic Gaussian time series generated by spectral densities, called spectrums, with a "box" shape. Three different spectrums have been used. In the acceptance probability in the MCMC algorithm, the likelihood have been built up by dividing the time series into blocks consisting of a constant number of points. In each block, only the maximum value, i.e. the extreme value, have been used. Each extreme value will then be interpreted as independent. Since the time series analysed are generated the way they are, there exists theoretical values for the parameters in the extreme value model. When the MCMC algorithm is tested to fit a model to the generated data, the true parameter values are already known. For the first and widest spectrum, the method is unable to find estimates matching the true values for the parameters in the extreme value model. For the two other spectrums, I obtained good estimates for some block lengths, others block lengths gave poor estimates compared to the true values. Finally, it looked like an increasing block length gave more accurate estimates as the spectrum became more narrow banded. A final simulation on a time series generated by a narrow banded spectrum, disproved this hypothesis.</p>