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As with most dune fields, the White Sands Dune Field in New Mexico forms in a wind regime that is not unimodal. In this study, dune behavior at White Sands was documented from a time series of five lidar-derived digital elevation models (DEM) and compared to a record of wind direction and speed during the same period. For the study period of June 2007 - June 2010, 244 sand-transporting wind events occurred and define a dominant wind mode from the SW and lesser modes from the NNW and SSE. Based upon difference maps and tracing of dune brinklines, overall dune behavior consists of migration to the NE, but with along-crest migration of dune sinuosity to the SE. Permutations of the DEMs allow matching specific dune behavior with wind modes. The SW winds are transverse to dune orientations and cause most forward migration. The NNW winds cause along-crest migration of dune sinuosity and low stoss bedforms, as well as SE migration of NE-trending dune terminations. The SSE winds cause ephemeral dune deformation, especially crestal slipface reversals. Dune deformation occurs because of unequal deposition along the lee face as a function of the incidence angle formed between the wind and the local brinkline orientation. Incidence-angle control on dune deformation and types of lee-face surface processes allows for an idealized model for White Sands dunes. The dunes behave as complex systems in which each wind event deforms the dune shape, this new shape then serves as the configuration for the next wind event. / text

No description available.

This study analyzes the 1993 Survey on Social Mobility and Social Change in China and is trying to find out whether Chinese nationalism affects regime support and in what direction. The thesis begins with the theories of nationalism, whose main events took part chiefly and, almost, exclusively, in Europe of the 19th century. Then, the roots of Chinese nationalism are explained along with the need to use the plural term nationalisms in order to point out the many faces of Chinese nationalism. There are presented some typologies of it as presented in bibliography. Furthermore, theoretical concepts such as regime, diffuse and specific support among others, which are used in the present study, are introduced to pave the way for the ensuing chapters. Moreover, the model that is used in the thesis is put forth in order to underline the key concepts and to support the use of the questionnaire in a meaningful and sufficient way. The dependent, intermediate, and independent variables are presented in order to conceptualize and operationalize them. After that, the data analysis follows, which test the theories suggested for Chinese nationalism. The results of the data analysis show that in 1993 not many factors of Chinese nationalism affect regime support. It is only the attitude toward China itself and foreign countries that have a statistically significant impact on regime support, therefore a 2x2 typology concerning Chinese nationalism and regime support is introduced.

The revaluation of the yuan in July 2005 was described by the Chinese central bank as a change in the currency regime, rather than merely a changed level of the exchange rate. The reform was said to involve a shift away from the fixed exchange rate, a gradual movement towards greater flexibility, and a peg to a basket of currencies. This paper closely examines the post-July Chinese currency regime utilising contemporary ideas in the econometrics of structural change. We find that the yuan has remained pegged to the US dollar, rather than to a basket, and has extremely limited currency flexibility. We find no evidence of structural change in the post-July period, which suggests that there has been no evolution towards greater flexibility. We show a monitoring procedure which will detect future evolution of the currency regime. / Series: Research Report Series / Department of Statistics and Mathematics

In a variety of industrial sectors the condition monitoring of induction machines is an important aspect of any condition based maintenance regime. To date, no panoptic means of assessing induction machine health from a single machine parameter exists, further, little work has been performed on the condition monitoring of inverter fed induction machines, an area of increasing importance. In addition, the signal processing tool Higher Order Spectra has been the subject of a great deal of research, and these tools have certain properties which make them ideal for application in a condition monitoring environment. However, limited published work exists in this area, with even less material describing Higher Order Spectra as an induction machine condition monitoring tool in a quantitative fashion. This thesis reconciles these two anomalies, and describes the application of Higher Order Spectra to induction machine condition monitoring. A number of induction machine fault conditions are analysed theoretically, and the subsequent effect of these faults on induction machine vibration described using simple system theory. Experimental results are presented and it is shown that Higher Order Spectra make the optimal diagnosis tool for these fault conditions. It is further shown that this diagnosis method is independent of the machine load and supply. Further, in the case of the inverter supply condition, this diagnosis is independent of the machine speed and in the majority of cases, the magnitude of the induction machine fault can also be identified using this technique. This allows a predicted time to catastrophic failure to be identified and the scheduling of maintenance in an appropriate and optimal manner. Finally, the entire diagnostic method is combined in an automated, software based diagnostic tool based on the previous analysis. It is shown that this tool provides diagnostic performance close to that for ideal induction machine condition monitoring and represents a relatively simple and inexpensive method of monitoring machine health independent of machine supply, load and speed.

This dissertation examines the American project in Iraq between 1991 and 2006. It studies the project's conceptual arc, shifting ontology, discourses, institutions, practices, and technologies in their interrelatedness to constitute a new Iraq. It is an ethnography of a thixotropic regime of law and order in translation; a circuit through various landscapes and temporalities to narrate the 1991 war, the institutionalization of sanctions and inspection regimes, material transformations within the American military, the 2003 war and finally the nation-building processes as a continuous and unitary project. The dissertation makes three central arguments: First, the 2003 war on Iraq was imagined through intricate and fluid spaces and temporalities. Transforming Iraq into a democratic regime has served as a catalyst for transforming the American military organization and the international legal system. Second, this project has reordered the spatialized time of Iraq by the imposition of models in translation, reconfigured and reimagined through a realm of violence. These models have created in Iraq a regime of differential mobility, which was enabled through an ensemble of experts, new institutions and calculative technologies. Third, this ensemble took Iraq as its object of knowledge and change rendering Iraq and Iraqis into a set of abstractions within the three spaces under examination: the space of American military institutions; the space of international legality within the United Nations; and, lastly, the material space of Baghdad. Part one examines the pre-invasion political, military, and legal practices that enabled the 2003 invasion and the so-called nation-building projects that ensued. In the American military space, the dissertation focuses on the 1991 and the 2003 military campaigns and operations and traces both campaigns in Iraq in terms of discourses of spatialization and temporalization to historicize the emergences of the so-called `revolution in military affairs' and its progression to a full-fledged theory of cyber-war renowned as network-centric warfare (NCW). In the UN space, this dissertation studies the forms of sovereignty that emerged through the political, legal, and military processes of the 1990s and early 2000s. The 1991 military campaign; post-1991 deployment of the United Nations' authority in order to establish, as an institution, the sanctions and inspection regimes; the 2003 invasion itself; and, finally, the re-siting of the Iraqi Archive: These events are the work of various technologies of violence and control which led to extensive asymmetrical movements of people and things in and about Iraq resituating the sovereignty of the state not within the territorial borders of Iraq but at the level of the globe. Part two studies the post-invasion regime of law and order imposed by the American occupation, its role in reconfiguring the architectural and social space of Baghdad, the identity of the city's population, and the persistent crisis in which the city was subsumed. The Iraqi legal system was flattened and remade with speed and intensity as a prerequisite for a new democratic Iraq creating a new set of laws to be administered by reorganized government institutions, and a new lexicon of political categories that has divided the city's population and mapped them onto the divided city-scape. In Bagdad's urban space, architectural barriers, empowered by new technologies of surveillance, targeting and identifications, have become a permanent element of the post-invasion system as spatial signifiers of law and order.

Conceitos e técnicas são ensinados em ambientes educacionais e deveriam ser aprendidos; porém, os exames nacionais de larga escala têm mostrado resultados indesejados, evidenciando uma lacuna na aprendizagem dos nossos alunos. Segundo Sanchez (2013), nos cursos de graduação em Ciências Contábeis, os principais erros conceituais cometidos pelos estudantes são: uso equivocado dos conceitos de caixa e competência e erros matemáticos. A definição de erro conceitual é referida na literatura sobre misconceptions (Chi, 1992) em que existe uma apresentação padrão na forma em que o erro desponta e um relacionamento incompatível entre os conceitos novos, a serem aprendidos pelos alunos, e os conceitos prévios, já existentes. Os erros conceituais têm seis características: são robustos, consistentes, persistentes, homogêneos, recapitulados e sistemáticos. Por isso, são difíceis de serem corrigidos. Chi et al (1994) utilizam da teoria da estruturação do conhecimento, em que definem que os conceitos são classificados em categorias ao serem aprendidos. Porém, conceitos que são classificados erroneamente transformam-se em erros conceituais robustos: são difíceis de serem aprendidos, pela dificuldade em transpor o conceito para a categoria adequada. Com base na definição de misconception e da estruturação dos conceitos em categorias, buscou-se entender como os estudantes formam os erros conceituais e, com base nestes tipos de erro encontrados e nas seis características dos padrões de erros, coletamos evidências da formação e superação dos erros por parte dos alunos. Estas evidências nos auxiliaram na criação de uma estratégia de ensino, construída com base na estruturação do conhecimento e, que seja diferente da estratégia \"comum\" de aula de Contabilidade Introdutória, que é o primeiro contato dos estudantes da área de negócios com contabilidade, com intuito de responder a nossa questão de pesquisa: \"Qual o impacto (proporção e sentido) da adoção desta estratégia de ensino baseada em erros conceituais no aprendizado dos estudantes?\" O impacto da estratégia foi motivacional, pois fez os alunos refletirem sobre os erros conceituais, mas insuficiente para aumentar a proporção de acertos nas avaliações realizadas. / Concepts and techniques are taught in educational settings and should be learned; however, large-scale national exams have shown undesirable results, evidencing a learning gap in our students. According to Sanchez (2013), in the undergraduate courses in Accounting, the main misconception made by students are: misuse of concepts of cash and accrual and mathematical errors. The definition of misconception is referred to in the literature (Chi, 1992) in which there is a standard presentation in the form in which the error emerges and an incompatible relationship between the new concepts to be learned by the students and the prior knowledge already existing. Misconception have six characteristics: they are robust, consistent, persistent, homogeneous, recapitulated and systematic. Therefore, they are difficult to correct. Chi et al. (1994) use the theory of knowledge structuring, where they define that concepts are classified into categories when they are learned. However, concepts that are misclassified become robust conceptual errors: they are difficult to learn because of the difficulty in transposing the concept into the appropriate category. Based on the definition of misconception and the structuring of concepts into categories, we sought to understand how students form misconception and, based on these types of errors found and on the six characteristics, we collect evidence of the formation and overcoming of errors on the part of the students. These evidences helped us in creating a teaching strategy, based on the structuring of knowledge and that is different from the \"common\" strategy of First Accounting Class, which is the first contact of the students of the business area with accounting, with In order to answer our research question: \"What is the impact (proportion and signal) of adopting this teaching strategy based on conceptual errors in learning?\" The impact of the strategy was motivational, as it made the students reflect on the conceptual errors, but insufficient to increase the proportion of correctness in the realized evaluations.

This thesis explores option pricing and hedging in a discrete time regime-switching environment. If the regime risk cannot be hedged away, then we cannot ignore this risk and use the Black-Scholes pricing and hedging framework to generate a unique pricing and hedging measure. We develop a risk neutral pricing measure by applying an Esscher Transform to the real world asset price process, with the focus on the issue of incompleteness of the market. The Esscher transform turns out to be a convenient and effective tool for option pricing under the discrete time regime switching models. We apply the pricing measure to both single variate European options and multivariate options. To better understand the effect of the pricing method, we also compared the results with those generated from two other risk neutral methods: the Black-Scholes model, and the natural equivalent martingale method. We further investigate the difference in hedging associated with different pricing measures. This is of interest when the choice of pricing method is uncertain under regime switching models. We compare four hedging strategies: delta hedging for the three risk neutral pricing methods under study, and mean variance hedging. We also develop a more general tool of tail ordering for hedging analysis in a general incomplete market with the uncertainty of the risk neutral measures. As a result of the analysis, we propose that pricing and hedging using the Esscher transform may be an effective strategy for a market where the regime switching process brings uncertainty.

Although globally used in option pricing, the Black-Scholes model has not been able to reflect the evolution of stocks in the real world. A regime-switching model which allows jumps in the underlying asset prices and the parameters of the corresponding stochastic process is more accurate. We evaluate the analytical solution for pricing of European options under a two-state regime switching model. Both the convergence of the analytical solution and the feature of implied volatility are investigated through numerical examples. We develop a number of techniques for pricing American options by solving the system of partial differential equations in a general \mathcal{K}-state regime-switching model. The linear complementarity problem is replaced by either the penalty or the direct control formulations. With an implicit discretization, we compare a number of iterative procedures (full policy iteration, fixed point-policy iteration, and local American iteration) for the associated nonlinear algebraic equations. Specifically, a linear system appears in the full policy iteration which can be solved directly or iteratively. Numerical tests indicate that the fixed point-policy iteration and the full-policy iteration (using a simple iteration for the linear system), both coupled with a penalty formulation, results in an efficient method. In addition, using a direct solution method to solve the linear system appearing in the full policy iteration is usually computationally very expensive depending on the jump parameters. A Fourier transform is applied to the system of partial differential equations for pricing American options to obtain a linear system of ordinary differential equations that can be solved explicitly at each timestep. We develop the Fourier space timestepping algorithm which incorporates a timestepping scheme in the frequency domain, in which the frequency domain prices are obtained by applying the discrete Fourier transform to the spatial domain. Close to quadratic convergence in time and space is observed for all regimes when using a second order Crank-Nicolson scheme for approximation of the explicit solution of the ordinary differential equation.