A manutenção do metabolismo mineral normal dos ossos é um resultado de vários fatores inclusive as solicitações mecânicas que são aplicadas aos ossos pelas contrações musculares e força da gravidade. O propósito desta investigação foi estudar um modelo de suspensão de rato pela cauda que simulasse assim as alterações esqueléticas que podem acontecer em um ambiente de microgravidade. O modelo foi analisado em termos de tolerância do animal e os efeitos sobre a resistência mecânica do complexo tíbia-fíbula. Após a realização do ensaio de flexão em três pontos foram obtidos os principais parâmetros mecânicos (carga e deflexão no limite máximo, carga e deflexão no limite elástico, rigidez e resiliência). Foram utilizadas cinqüenta e três ratas fêmeas, distribuídas em quatro grupos conforme o período de suspensão (controle, 7, 14 e 21 dias). O modelo de suspensão mostrou-se eficaz com boa adaptação dos animais e promoveu um enfraquecimento significativo nos ossos principalmente no período de 21 dias / The maintenance of the normal metabolism of minerals in bone is a result of several factors including the mechanical demands that are applied to the bones by the muscle contractions and gravity force. The purpose of this investigation was to study a model of tail suspension of the rat thus simulating the skeletal alterations that may occur in a microgravity environment. The model was analyzed in terms of animal tolerance and the ensuing effects on the mechanical resistance of the tibiofibular complex. After a three-point bending test in flexion the main mechanical parameters were obtained, (load and deflection at the ultimate limit, load and deflection at the yielding point, stiffness and resilience). Fifty-three adult female rats were used and distributed in four groups according to the length of time in suspension (control, 7, 14 and 21 days). The model of suspension was efficient with well adaptation of the animals and caused a significative weakness of bones mainly in the 21 day period

Tato diplomová práce se zabývá návrhem stavitelného stabilizátoru za účelem vyvažování letounu a zlepšení jeho letových výkonů. Cílem práce bylo navrhnout konstrukční řešení ovládání a zavěšení horizontálního stabilizátoru. Součástí je pevnostní výpočet kritických konstrukčních prvků a návrh letových zkoušek. V závěru jsou zhodnoceny výhody a nevýhody nového řešení a posouzení možnosti sériové výroby. Klíčová slova Ultralight, JA – 400, stabilizátor, stavitelný stabilizátor, vodorovné ocasní plochy, vyvážení. Abstract This thesis describes the design of adjustable stabilizer for the purpose of balancing the aircraft and improve its flight performance. The aim was to propose a design solution for control and hinge system of horizontal stabilizer. It includes the strength calculation of critical structural components and the design of flight tests. The conclusion evaluates the pros and cons of the new solutions and possibilities of mass production.

The object of diploma thesis is a loading determination for strength calculation of HPH 2 Twin Shark glider matching the requirements of Certification Specification for Sailplanes (CS-22). Loading of the wing, tail section, fuselage and undercarriage is determined in this work.

We consider tail empirical processes for long memory stochastic volatility models with heavy tails and leverage. We show a dichotomous behaviour for the tail empirical process with fixed levels, according to the interplay between the long memory parameter and the tail index; leverage does not play a role. On the other hand, the tail empirical process with random levels is not affected by either long memory or leverage. The tail empirical process with random levels is used to construct a family of estimators of the tail index, including the famous Hill estimator and harmonic moment estimators. The limiting behaviour of these estimators is not affected by either long memory or leverage. Furthermore, we consider estimators of risk measures such as Value-at-Risk and Expected Shortfall. In these cases, the limiting behaviour is affected by long memory, but it is not affected by leverage. The theoretical results are illustrated by simulation studies.

We model Normal Inverse Gaussian distributed log-returns with the assumption of stochastic volatility. We consider different methods of parametrization of returns and following the paper of Lindberg, [21] we assume that the volatility is a linear function of the number of trades. In addition to the Lindberg’s paper, we suggest daily stock volumes and amounts as alternative measures of the volatility. As an application of the models, we perform Value-at-Risk and Expected Tail Loss predictions by the Lindberg’s volatility model and by our own suggested model. These applications are new and not described in the literature. For better understanding of our caluclations, programmes and simulations, basic informations and properties about the Normal Inverse Gaussian and Inverse Gaussian distributions are provided. Practical applications of the models are implemented on the Nasdaq-OMX, where we have calculated Value-at-Risk and Expected Tail Loss for the Ericsson B stock data during the period 1999 to 2004.

Sexual selection is one of main selective pressure affecting body size, and subsequently leads to the evolution of sexual size dimorphism (SSD). The eyelid geckoes, family Eublepharidae, are a monophyletic group with considerable variability in SSD, including both male-larger and female-larger species. In general, it was supposed that eyelid geckos are highly variable in presence of male combats and in complexity of male pre-copulatory behaviour, and that this variability in this conspicuous male behaviour may lead to differences in SSD. The aim of this study was to reveal relationships between the direction of SSD and presence/absence of tail vibration during precopulatory phase and male combat behaviour. Using behavioural testing, it was revealed that male combats are present in all tested species, even in species, where the absence of such behaviour was supposed so far. In several species, the strong effect of seasonality to male aggression was observed, which may play a role in the evolution of SSD. The evolutionary changes in the presence/absence of tail vibration during precopulatory phase were independent on changes in the direction of SSD, the presence of tail vibration seems to be ancestral state for these lizards. During the evolution of this group, the tail vibrations disappeared four...

The tail in mammals is an important organ, which in contrast to most vertebrae, doesn't add to the motor function of their bodies. The use of the mamals' tail is much more varied and it can fulfill many different functions. This work includes a survey of these functions and analyzes collected data concerning 553 spieces of mammals across all families. The data includes information about the length of tail, the length of body, body mass, living environment and outer signs on the anal pole of these species. The resulting analysis concludes that the tail length is dependent both on the length of the mammal's body and its living environment. Outward signs of the tail depend on its length as well as the length of the body and the living environment. Distinctive tail ending and tail base probably fulfill a communicative function. The tail is more likely to have communication than cryptic significance.

In this thesis, fast Viterbi Decoder algorithms for a multi-core system are studied. New parallel Viterbi algorithms for decoding convolutional codes are proposed based on tail biting trellises. The performances of the new algorithms are first evaluated by MATLAB and then Eagle (E-UTRA algorithms for LTE) link level simulations where the optimal parameter settings are obtained based on various simulations. One of the algorithms is proposed for implementation in the product due to its good BLER performance and low implementation complexity. The new parallel algorithm is then implemented on target DSPs for Ericsson internal multi-core system to decode the PUSCH (Physical Uplink Shared Channel) CQI (Channel Quality Indicator) in LTE (Long Term Evolution). And the performance of the new algorithm in the real multi-core system is compared against the current implementation regarding both cycle and memory consumption. As a fast decoder, the proposed parallel Viterbi decoder is computationally efficient which reduces significantly the decoding latency and solves memory limitation problems on DSP.

It has been noticed that one of the main challenges for e-commerce sites is providing the users with an efficient search function. It has also been noticed that the search function is one of the things the user is valuing the most when evaluating an e-commerce. The information technology enables the possibility to consume almost anything one could wish for. The challenge is in how to find this specific item. It is hence of interest to examine how to improve the search tool and what effect the updated search tool results in. The objective of this research is twofold. The objective motivated by economic factors is to examine how a user’s ability to find relevant items is affected by being able to refine a search result by selecting relevant attribute values. The other objective has a more technical character and is to examine how the rule based method performs in terms of extracting attribute values for enable the creation of the filtering function. The examinations for this research is conducted at a Swedish online auction company that due to the structure of its e-catalogue provides a suitable setup for the examinations. Because of the examinations being conducted in the environment of the auction company’s system this limits the result to only being representative for data with the same characteristics as the auction company’s. For answering the questions stated in the objective two methods are applied. One for examining the economic part and one for examining the technical part. The economic question is answered after analysing the result of an A/B-test conducted at the auction company. For answering the technical examination an information extraction technique is evaluated. The result of the economical examination is that a significant increase in conversion rate can be concluded for the system version with filtering enabled. The result of the technical examination shows that the rule based method can be used for information extraction in some cases. However, the obtained accuracy will be affected by the characteristics of the data the information extraction is performed on.

Masters of Commerce / If share price fluctuations follow a simple random walk then it implies that forecasting models based on historical growth rates have little ability to forecast acceptable share price movements over a certain period. The simple random walk description of share price dynamics is obtained when a large number of investors have equal probability to buy or sell based on their own opinion. This simple random walk description of the stock market is in essence the Efficient Market Hypothesis, EMT. EMT is the central concept around which financial modelling is based which includes the Black-Scholes model and other important theoretical underpinnings of capital market theory like mean-variance portfolio selection, arbitrage pricing theory (APT), security market line and capital asset pricing model (CAPM). These theories, which postulates that risk can be reduced to zero sets the foundation for option pricing and is a key component in financial software packages used for pricing and forecasting in the financial industry. The model used by Black and Scholes and other models mentioned above are Gaussian, i.e. they exhibit a random nature. This Gaussian property and the existence of expected returns and continuous time paths (also Gaussian properties) allow the use of stochastic calculus to solve complex Black- Scholes models. However, if the markets are not Gaussian then the idea that risk can be. (educed to zero can lead to a misleading and potentially disastrous sense of security on the financial markets. This study project test the null hypothesis - share prices on the JSE follow a random walk - by means of graphical techniques such as symmetry plots and Quantile-Quantile plots to analyse the test distributions. In both graphical techniques evidence for the rejection of normality was found. Evidenceleading to the rejection of the hypothesis was also found through nonparametric or distribution free methods at a 1% level of significance for Anderson-Darling and Runs test.