<p>The subject for this thesis is to find a basis which minimizes the number of bit operations involved in a finite field multiplication. The number of bases of a finite field increases quickly with the extension degree, and it is therefore important to find efficient search algorithms. Only fields of characteristic two are considered. </p><p>A complexity measure is introduced, in order to compare bases. Different methods and algorithms are tried out, limiting the search in order to explore larger fields. The concept of equivalent bases is introduced. </p><p>A comparison is also made between the Polynomial, Normal and Triangular Bases, referred to as known bases, as they are commonly used in implementations. Tables of the best found known bases for all fields up to GF(2^24) is presented. </p><p>A list of the best found bases for all fields up to GF(2^25) is also given.</p>

<p>This thesis investigates architectures for multiplying elements in Galois rings of the size 4^m, where m is an integer. </p><p>The main question is whether known architectures for multiplying in Galois fields can be used for Galois rings also, with small modifications, and the answer to that question is that they can. </p><p>Different representations for elements in Galois rings are also explored, and the performance of multipliers for the different representations is investigated.</p>

<p>The different mapping techniques that are used increases the details on surfaces without increasing the number of polygons. Image Based Sculpting tools in the program Modo and Z-Brush is used to create folds and wrinkles from photographs of actual fabrics instead of trying to create these shapes by modeling them. This method makes it easier to achieve photorealistic renderings and produce as realistic fabric dynamics as possible when they are applied on objects.</p>

<p>Riskvärdering har under 90-talet blivit ett allt mer medvetet begrepp. Ett populärt instrument vid riskvärdering är Value at Risk då denna modell skapar ett gemensamt riskmått för olika typer av portföljer och derivat. VaR mäter den maximala värdeförändringen för en portfölj där sannolikheten och tidshorisonten är förutbestämd. I uppsatsen har en konfidensnivå på 95 procent antagits vilket medför att de verkliga förlusterna ska överstiga VaR en gång av tjugo.</p><p>Icke-linjära instrument, såsom optioner, är svåra att riskvärdera då dess pris förändras oproportionerligt gentemot dess underliggande. För att beräkna VaR kan flertalet modeller appliceras och dessa har olika egenskaper.</p><p>Det är därför av intresse att ta reda på om Delta-Normal metoden, Monte Carlo simulering och Historisk simulering ger samma svar vid riskvärdering av optioner. Vidare syftar denna uppsats till att söka svar på om dessa tre VaR-modeller ger ett tillfredsställande resultat på 95 procentig konfidensnivå. För att få svar på dessa funderingar har vi i empiriavsnittet genomfört två hypotesprövningar.</p><p>Den första slutsatsen som kan dras av undersökningen är att det inte går att skilja på det VaR som Delta-Normal metoden och Historisk simulering tagit fram. Vid ett hypotestest för proportioner blev resultatet att endast för Monte Carlo simuleringen kunde inte nollhypotesen förkastas. Detta innebär att det finns stöd för att de verkliga förlusterna överstiger Monte Carlo simuleringens beräknade VaR en gång av tjugo.</p>

<p>Even though the goals of Swedish disability-politics are equality, full participation and autonomy, people with disabilities almost every day encounter discrimination and oppression. This thesis deals with the question of the public service-medias role in this discrepancy between political rhetoric and practices. The study of mass media’s role is interesting considering its cultural impact and the importance of cultural values in all kinds of communication situations. The focus of the study is on Swedish public service-television and the aim is to investigate the role of SVT in the implementation of the political goals of disability-politics. To what extent do SVT promote these goals and to what extent do they counteract them? The study’s ambition is both descriptive and analytical. Theoretically the study takes as its point of departure a social constructionist perspective. The only reality we thus can get in contact with is one that, via our language, has passed through our former knowledge and experiences. Language is therefore the main object of study. Another theoretical point of departure is a normative view on the role of mass media in society. This approach is characterized by the assumption that mass media has a certain usefulness for society as a whole, which in itself is a central purpose for public service-media.</p><p>The study is based on data consisting of programme descriptions and video copies of programmes from the start of SVT in 1956 until 2 000. Altogether it represents more than </p><p>2 000 TV-programmes and over 40 000 broadcasting hours. Furthermore, the data consist of official political documents regarding media and disability matters. The data are approached from a discourse-analytical perspective and investigated in three studies. One of the data clusters was used to carry out a quantitative outline of SVT’s representations of disability. Another was used in an analysis of the socio-historical context and its changes over time and yet another was an analysis of the contents and narratives of the programmes.</p><p>The main conclusions are that disabled persons and programmes that deals with disability issues are, and has been, rare in SVT, not more than 1-2 hours per 1 000 broadcast hours. The amount is the same today as it was in 1956. Another conclusion is that even though it seems like SVT is trying to promote the goals of disability-politics the consequences appears to be that SVT instead counteract them. One reason might be that the dominating representation in SVT has been of disability and disabled persons as normal. But because of journalistic practices, the outcome becomes portrays of deviance and The Other. This solution, however, is too simplistic. There is also a problem with the political rhetoric. As long as political goals, formulated in terms of ideals, which by definition are impossible to achieve, there will always be a discrepancy between political rhetoric and practices. The final conclusion therefore, is that reflections need to be done and consciousness needs to be raised in order to discover the discrepancy and from that point, try to create a change. </p>

<p>The face of the Earth is constantly renewed by continental rifts that open and allow ridges to spread oceanic floor. Both types of these linear extensional structures are morphologically and structurally segmented. This thesis aims to provide insights into the interaction of such segments as they propagate and mature. It is based on the results of analogue models of evolving rifts and ridges together with field studies of populations of dilational normal faults in the active rift zone of Iceland. Linkage of initially separate segments along rifts and ridges leads to formation of through-going systems operating on a planetary scale. It is argued here that the processes of segment initiation and growth are effectively scale-independent and essentially the same in wide and narrow modes of extension and for shear and dilational failure. Three distinct types of segment coalescence are recognized; these involve tip-to-tip, one tip-to-sidewall and two tips-to-sidewalls segment linkage. The overall structural pattern, particularly the width of the extending domain and the range of displacements and orientations of smaller-scale internal extensional structures, is influenced by both the geometry of extension and the mechanical properties of the extending material. Types of segment linkage appear to be largely independent of localization of dilation or intensity of magmatic accretion. Instead they are controlled mainly by the relative distribution and orientation of interacting segments. A few orders of segmentation along global rift-ridge systems and arrays of dilational normal faults indicate that linear continuous structures accumulate extension in successive increments during which the segments change their geometries in semi-continuous interaction and coalescence.</p>

<p>Long time average wind conditions at potential wind turbine sites are of great importance when deciding if an investment will be economically safe. Wind climate estimates such as these are traditionally done with in situ measurements for a number of months. During recent years, a wind climate database has been developed at the Department of Earth Sciences, Meteorology at Uppsala University. The database is based on model runs with the higher order closure mesoscale MIUU-model in combination with long term statistics of the geostrophic wind, and is now used as a complement to in situ measurements, hence speeding up the process of turbine siting. With this background, a study has been made investigating how well actual power productions during the years 2004-2006 from 21 Swedish wind turbines correlate with theoretically derived power productions for the corresponding sites.</p><p>When comparing theoretically derived power productions based on long term statistics with measurements from a shorter time period, correction is necessary to be able to make relevant comparisons. This normal year correction is a main focus, and a number of different wind energy indices which are used for this purpose are evaluated. Two publicly available (Swedish and Danish Wind Index) and one derived theoretically from physical relationships and NCEP/NCAR reanalysis data (Geostrophic Wind Index). Initial testing suggests in some cases very different results when correcting with the three indices and further investigation is necessary. An evaluation of the Geostrophic Wind Index is made with the use of in situ measurements.</p><p>When correcting measurement periods limited in time to a long term average, a larger statistical dispersion is expected with shorter measurement periods, decreasing with longer periods. In order to investigate this assumption, a wind speed measurement dataset of 7 years were corrected with the Geostrophic Wind Index, simulating a number of hypothetical measurement periods of various lengths. When normal year correcting a measurement period of specific length, the statistical dispersion decreases significantly during the first 10 months. A reduction to about half the initial statistical dispersion can be seen after just 5 months of measurements.</p><p>Results show that the theoretical normal year corrected power productions in general are around 15-20% lower than expected. A probable explanation for the larger part of this bias is serious problems with the reported time-not-in-operation for wind turbines in official power production statistics. This makes it impossible to compare actual power production with theoretically derived without more detailed information. The theoretically derived Geostrophic Wind Index correlates well to measurements, however a theoretically expected cubed relationship of wind speed seem to account for the total energy of the wind. Such an amount of energy can not be absorbed by the wind turbines when wind speed conditions are a lot higher than normal.</p> / <p>Vindklimatet vid tänkbara platser för uppförande av vindkraftverk är avgörande när det beslutas huruvida det är en lämplig placering eller ej. Bedömning av vindklimatet görs vanligtvis genom vindmätningar på plats under ett antal månader. Under de senaste åren har en vindkarteringsdatabas utvecklats vid Institutionen för Geovetenskaper, Meteorologi vid Uppsala universitet. Databasen baseras på modellkörningar av en högre ordningens mesoskale-modell, MIUU-modellen, i kombination med klimatologisk statistik för den geostrofiska vinden. Denna används numera som komplement till vindmätningar på plats, vilket snabbar upp bedömningen av lämpliga platser. Mot denna bakgrund har en studie genomförts som undersöker hur bra faktisk energiproduktion under åren 2004-2006 från 21 vindkraftverk stämmer överens med teoretiskt härledd förväntad energiproduktion för motsvarande platser. Om teoretiskt härledd energiproduktion baserad på långtidsstatistik ska jämföras med mätningar från en kortare tidsperiod måste korrektion ske för att kunna göra relevanta jämförelser. Denna normalårskorrektion genomförs med hjälp av olika vindenergiindex. En utvärdering av de som finns allmänt tillgängliga (Svenskt vindindex och Danskt vindindex) och ett som härletts teoretiskt från fysikaliska samband och NCEP/NCAR återanalysdata (Geostrofiskt vindindex) görs. Inledande tester antyder att man får varierande resultat med de tre indexen och en djupare utvärdering genomförs, framförallt av det Geostrofiska vindindexet där vindmätningar används för att söka verifiera dess giltighet.</p><p>När kortare tidsbegränsade mätperioder korrigeras till ett långtidsmedelvärde förväntas en större statistisk spridning vid kortare mätperioder, minskande med ökande mätlängd. För att undersöka detta antagande används 7 års vindmätningar som korrigeras med det Geostrofiska vindindexet. I detta simuleras ett antal hypotetiskt tänkta mätperioder av olika längd. När en mätperiod av specifik längd normalårskorrigeras minskar den statistiska spridningen kraftigt under de första 10 månaderna. En halvering av den inledande statistiska spridningen kan ses efter endast 5 månaders mätningar.</p><p>Resultaten visar att teoretiskt härledd normalårskorrigerad energiproduktion generellt är ungefär 15-20% lägre än väntat. En trolig förklaring till merparten av denna skillnad är allvarliga problem med rapporterad hindertid för vindkraftverk i den officiella statistiken. Något som gör det omöjligt att jämföra faktisk energiproduktion med teoretiskt härledd utan mer detaljerad information. Det teoretiskt härledda Geostrofiska vindindexet stämmer väl överens med vindmätningar. Ett teoretiskt förväntat förhållande där energi är proportionellt mot kuben av vindhastigheten visar sig rimligen ta hänsyn till den totala energin i vinden. En sådan energimängd kan inte tas till vara av vindkraftverk när vindhastighetsförhållandena är avsevärt högre än de normala.</p>

This dissertation attempts to answer the question, "How is truth communicated through fiction?" It begins with an analysis of theories of fiction that have been given in analytic philosophy. Then, it frames the question in terms of a response to the "war" between philosophy and poetry, represented by Plato's Socrates, who sees a variety of problems with allowing that poetry can teach ethical behavior, and Sir Philip Sidney, who believes that poetry has a great ability to teach. At the heart of the disagreement between the two is a question about the relationship between truth and the kind of communication that takes place in poetry, which is everywhere assumed rather than stated and argued for. The dissertation then continues to work toward an answer to its main question. First it looks at the theories of several continental philosophers who had things to say that hint at the direction to go in answering the question. The last two chapters are an attempt to give and support an answer to the question; imput is drawn from sources as various as Leonard Nimoy, Dorothy Sayer's "Gaudy Night," Linda Young's "Remember WENN" website, and academic literary theory; and the question is given a direct answer in the last chapter. There are three things that all fiction does that makes it communicate truth in a specific manner: all fiction attempts to engage, purports to describe the normal, and actually makes normative implications. It is because of this that fiction is the dangerous but potentially beneficial thing that Plato and Sidney respectively see it as.

Theoretical and experimental modal analysis, i.e., the computation of vibration modes from a mathematical model and from experimental data, respectively, is quite sophisticated and advanced in linear structural dynamics. However, nonlinearity is a frequent occurrence in real-world engineering structures, and the existing linear methodologies fail dramatically in the presence of nonlinear dynamical phenomena. Therefore, the present thesis focuses on the development of a practical nonlinear analog of modal analysis for properly accounting for nonlinearity in mechanical systems. The concept of nonlinear normal mode (NNM) provides solid mathematical and theoretical foundations for a rigorous, yet understandable by the practicing engineer, analysis of nonlinear dynamical behaviors. In this context, a useful framework for nonlinear modal analysis of vibrating structures, which includes the computation of NNMs from finite element models and their identification from experimental data, is proposed in this dissertation. In view of the still limited use of NNMs in structural dynamics, special attention is devoted to progress toward a practical tool that has the potential to deal with large-scale, real-world structures. Targeting an effective and exact computation of NNMs, even in strongly nonlinear regimes of motion, one original contribution of this work is to resort to numerical methods. An algorithm combining a shooting procedure and the so-called pseudo-arclength continuation method is developed. On the other hand, a nonlinear extension of phase resonance testing (also known as force appropriation) is introduced for the experimental identification of NNMs, which is another innovative aspect of the doctoral thesis. In particular, the phase lag quadrature criterion, which is used for linear experimental modal analysis, is generalized in the presence of nonlinear dynamical behavior. Academic examples are first considered to illustrate, in a simple manner, that the proposed methods form an effective and adequate framework for nonlinear modal analysis. Furthermore, more realistic structures, including a full-scale aircraft, are studied to demonstrate the potential applicability of the approach to large-scale, real-life applications.

Die vorliegende Diplomarbeit beschäftigt sich mit zwei Aspekten der statistischen Eigenschaften von Clusterverfahren. Zum einen geht die Arbeit auf die Frage der Existenz von unterschiedlichen Clusteranalysemethoden zur Strukturfindung und deren unterschiedlichen Vorgehensweisen ein. Die Methode des Abstandes zwischen Mannigfaltigkeiten und die K-means Methode liefern ausgehend von gleichen Daten unterschiedliche Endclusterungen. Der zweite Teil dieser Arbeit beschäftigt sich näher mit den asymptotischen Eigenschaften des K-means Verfahrens. Hierbei ist die Menge der optimalen Clusterzentren konsistent. Bei Vergrößerung des Stichprobenumfangs gegen Unendlich konvergiert diese in Wahrscheinlichkeit gegen die Menge der Clusterzentren, die das Varianzkriterium minimiert. Ebenfalls konvergiert die Menge der optimalen Clusterzentren für n gegen Unendlich gegen eine Normalverteilung. Es hat sich dabei ergeben, dass die einzelnen Clusterzentren voneinander abhängen. / The following thesis describes two different views onto the statistical characterics of clustering procedures. At first it adresses the questions whether different clustering methods exist to ascertain the structure of clusters and in what ays the strategies of these methods differ from each other. The method of distance between the manifolds as well as the k-means method provide different final clusters based on equal initial data. The second part of the thesis concentrates on asymptotic properties of the k-means procedure. Here the amount of optimal clustering centres is consistent. If the size of the sample range is enlarged towards infinity, it also converges in probability towards the amount of clustering centres which minimized the whithin cluster sum of squares. Likewise the amount of optimal clustering centres converges for infinity towards the normal distribution. The main result shows that the individual clustering centres are dependent on each other.