Structures acting as waveguides are quite common withexamples being, construction beams, fluid filled pipes, railsand extruded aluminium profiles. Curved structures like cartyres and pipe-bends may also be considered as waveguides. Wavesolutions in such structures may be found by a method calledthe Waveguide Finite Element Method or WFEM. This method uses afinite element approach on the cross-section of a waveguide tomodel the vibro-acoustic response as a set of linear, coupled,one dimensional, wave-equations. In this thesis six novel waveguide finite elements arederived and validated. These elements are, straight and curvedpre-stressed, orthotropic or anisotropic shell elements,straight and curved fluid elements, and straight and curvedfluid-shell coupling elements. Forced response and input power calculations for infiniteand periodic waveguides are presented. The assembled waveguidemodels can also serve as input for the Super Spectral FiniteElement Method, which enables forced response calculations formore complex boundaries. Furthermore, several properties ofdamped and undamped wave solutions are investigated. Finally, a car tyre model, encompassing for the highlyanisotropic material and the air cavity inside the tyre is setforth. A number of forced response calculations for this modelare presented and compared with measurements with goodagreement. Keywords:wave equation, wave solution, waveguide,finite element, spectral finite element, tyre noise, tyrevibration, input power, shells, pre-stress, fluid-shellcoupling axi-symmetric, two-and-half-dimensional

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Financial speculation has increased dramatically over the last 30 years. This means that a practice that used to be viewed as immoral gambling has become legitimate financial trade. This book explores the genealogy of the coexisting insider trading laws. The insider regulation prohibits trade based on privileged information in order to create equal trading conditions, and in this way uphold confidence in the financial markets among the general public. However, this study shows that the existing view of the insider regulation is misleading and that the regulation is best understood as a game rule aiming to stimulate financial speculation. The protection interest is therefore not primarily the general public, but the financial system as such: the professional market actors sustaining the speculative activities and a growing financial sector. The consequence of stimulating financial speculation is that today’s authorities are attempting to make the financial markets into a lotto-like game, rather than a market for long-term investment. To make the financial markets into liquid and volatile public “games” means that the risks involved in the financial speculation are created by the human hand and the economic system itself rather than being naturally given. This places desire rather than rational needs as the fundamental ground of the economy. The concluding question is; why are we making our economy into a game?

En esta tesis se reinterpreta la idea de “tecnología” partiendo de los ejemplos etnográficos de varias comunidades ribereñas del Bajo Amazonas. La situación híbrida de estos ribereños, que mantienen las técnicas tradicionales indígenas y a la vez se acomodan al influjo de la modernidad, permite establecer un eje de simetría entre la tecnología amazónica y la occidental. El objetivo teórico es demostrar que la idea de “tecnología” se ha definido desde Occidente en términos etnocéntricos, esto es, identificándola con las máquinas y artefactos que han generado el desarrollo industrial a base de dominar un entorno natural opuesto simbólicamente a la cultura humana. La tecnología de los ribereños, sin embargo, no se cifra en esos parámetros, sino que debe rastrearse en sus modos de utilizar el cuerpo, en el conocimiento implícito y en las circunstancias (más sociales que técnicas) de la modernización y la política agraria brasileña. Partiendo de estas cuatro dimensiones sociotécnicas, se verá cómo la perspectiva antropológica puede proporcionar un cuadro interpretativo de la tecnología que la llevaría más allá de su caracterización occidental. Si el pensamiento moderno la ha presentado como el instrumento con el que la sociedad logra emanciparse de la naturaleza, aquí se van a invertir dichos términos, para definirla como una estrategia de relación con el entorno por la que precisamente se refuerza la mímesis entre lo “social” y lo “natural”. / This thesis develops a reinterpretation of the idea of “technology” by focusing on the ethnographical examples of several Lower Amazon riverine communities. The hybrid situation of the riverines, who still maintain the indigenous traditional techniques and at the same time are influenced by modernity, allows us to establish an axis of symmetry between native and western technologies. The theoretical objective is to show that technology has been defined by the West in ethnocentric terms, this is, identifying it with the machines and artefacts that generated the industrial development by dominating a natural environment that is symbolically opposed to human culture. Riverines technology, however, can’t be understood through these parameters, but rather through their body uses, their implicit knowledge and the circumstances (more social than technical) of modernization and the Brazilian agrarian politics. Regarding to these four sociotechnical dimensions, it will be seen how anthropology provides an interpretative frame that leads technology beyond its Western characterisation. While modern thought has represented it as the instrument with which society becomes emancipated form nature, here these terms will be reversed, aiming to define technology as a strategy of relation with the environment that precisely reinforces the mimesis between the “social” and the “natural”.

This master's thesis addresses numerical methods of computing the typical ranks of tensors over the real numbers and explores some properties of tensors over finite fields. We present three numerical methods to compute typical tensor rank. Two of these have already been published and can be used to calculate the lowest typical ranks of tensors and an approximate percentage of how many tensors have the lowest typical ranks (for some tensor formats), respectively. The third method was developed by the authors with the intent to be able to discern if there is more than one typical rank. Some results from the method are presented but are inconclusive. In the area of tensors over nite filds some new results are shown, namely that there are eight GLq(2) GLq(2) GLq(2)-orbits of 2 2 2 tensors over any finite field and that some tensors over Fq have lower rank when considered as tensors over Fq2 . Furthermore, it is shown that some symmetric tensors over F2 do not have a symmetric rank and that there are tensors over some other finite fields which have a larger symmetric rank than rank.

This thesis is focused on hash families and cover-free families and their application to problems in cryptography. We present new necessary conditions for generalized separating hash families, and provide new explicit constructions. We then consider three cryptographic applications of hash families and cover-free families. We provide a stronger de nition of anonymity in the context of shared symmetric key primitives and give a new scheme with improved anonymity properties. Second, we observe that nding the invalid signatures in a set of digital signatures that fails batch veri cation is a group testing problem, then apply and compare many group testing algorithms to solve this problem e ciently. In particular, we apply group testing algorithms based on cover-free families. Finally, we construct a one-time signature scheme based on cover-free families with short signatures.

The study of properties of probability distributions has always been a persistent theme of statistics and of applied probability. This thesis deals with an investigation of distribution functions under the following two topics: (i) characterization of distributions based on record values and order statistics, (ii) properties of the skew-t distribution. Within the extensive characterization literature there are several results involving properties of record values and order statistics. Although there have been many well known results already developed, it is still of great interest to find new characterization of distributions based on record values and order statistics. In the first part, we provide the conditional distribution of any record value given the maximum order statistics and study characterizations of distributions based on record values and the maximum order statistics. We also give some characterizations of the mean value function within the class of order statistics point processes, by using certain relations between the conditional moments of the jump times or current lives. These results can be applied to characterize the uniform distribution using the sequence of order statistics, and the exponential distribution using the sequence of record values, respectively. Azzalini (1985, 1986) introduced the skew-normal distribution which includes the normal distribution and has some properties like the normal and yet is skew. This class of distributions is useful in studying robustness and for modeling skewness. Since then, skew-symmetric distributions have been proposed by many authors. In the second part, the so-called generalized skew-t distribution is defined and studied. Examples of distributions in this class, generated by the ratio of two independent skew-symmetric distributions, are given. We also investigate properties of the skew-symmetric distribution.

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<p>Structures acting as waveguides are quite common withexamples being, construction beams, fluid filled pipes, railsand extruded aluminium profiles. Curved structures like cartyres and pipe-bends may also be considered as waveguides. Wavesolutions in such structures may be found by a method calledthe Waveguide Finite Element Method or WFEM. This method uses afinite element approach on the cross-section of a waveguide tomodel the vibro-acoustic response as a set of linear, coupled,one dimensional, wave-equations.</p><p>In this thesis six novel waveguide finite elements arederived and validated. These elements are, straight and curvedpre-stressed, orthotropic or anisotropic shell elements,straight and curved fluid elements, and straight and curvedfluid-shell coupling elements.</p><p>Forced response and input power calculations for infiniteand periodic waveguides are presented. The assembled waveguidemodels can also serve as input for the Super Spectral FiniteElement Method, which enables forced response calculations formore complex boundaries. Furthermore, several properties ofdamped and undamped wave solutions are investigated.</p><p>Finally, a car tyre model, encompassing for the highlyanisotropic material and the air cavity inside the tyre is setforth. A number of forced response calculations for this modelare presented and compared with measurements with goodagreement.</p><p><b>Keywords:</b>wave equation, wave solution, waveguide,finite element, spectral finite element, tyre noise, tyrevibration, input power, shells, pre-stress, fluid-shellcoupling axi-symmetric, two-and-half-dimensional</p>

This thesis is focused on hash families and cover-free families and their application to problems in cryptography. We present new necessary conditions for generalized separating hash families, and provide new explicit constructions. We then consider three cryptographic applications of hash families and cover-free families. We provide a stronger de nition of anonymity in the context of shared symmetric key primitives and give a new scheme with improved anonymity properties. Second, we observe that nding the invalid signatures in a set of digital signatures that fails batch veri cation is a group testing problem, then apply and compare many group testing algorithms to solve this problem e ciently. In particular, we apply group testing algorithms based on cover-free families. Finally, we construct a one-time signature scheme based on cover-free families with short signatures.