My thesis is titled Trolling and other unusual online behaviours. It focuses on deviant behaviours of internet users in Czech and foreign context. Trolling and hate became inseparable part of online environment, it is sort of a side product of the development of technology. The aim of this thesis is to reveal strategies hidden behind behaviour of users of the internet who intentionally disrupt the continuity of online environment (trolling etc.), also depicting the profile of this kind of internet user, characterizing him and describing his way of doings and his impact on other users. In the theoretical part I characterize fundamental terms which are related to the topic. These include terms like flame wars, hoax etc. In this part I also attempted to describe the troubled history of online deviant behaviour which dates back to the eighties. Historic analysis of huge amount of online articles was a big help in this task because the scientific literature related to the topic is not available. In the practical part I used quantitative and qualitative analysis. Using questionnaire survey in which 225 respondents took part I explored public attitude to deviant behaviour (trolling). By qualitative interviews with five trolls I investigated the motives of deviant users of internet, how they are influenced...

We study the large deviation behaviour of simple random walks in dimension three or more in this thesis. The first part of the thesis concerns the number of lattice sites visited by the random walk. We call this the range of the random walk. We derive a large deviation principle for the probability that the range of simple random walk deviates from its mean. Our result describes the behaviour for deviation below the typical value. This is a result analogous to that obtained by van den Berg, Bolthausen, and den Hollander for the volume of the Wiener sausage. In the second part of the thesis, we are interested in the number of lattice sites visited by two independent simple random walks starting at the origin. We call this the intersection of ranges. We derive a large deviation principle for the probability that the intersection of ranges by time n exceeds a multiple of n. This is also an analogous result of the intersection volume of two independent Wiener sausages.

Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-06-11T14:42:40Z No. of bitstreams: 1 Dissertação -Daniely Amorim de Meireles.pdf: 13588025 bytes, checksum: 907abba7b19235b598e2c627358f9b82 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-11T18:30:35Z (GMT) No. of bitstreams: 1 Dissertação -Daniely Amorim de Meireles.pdf: 13588025 bytes, checksum: 907abba7b19235b598e2c627358f9b82 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-11T20:33:35Z (GMT) No. of bitstreams: 1 Dissertação -Daniely Amorim de Meireles.pdf: 13588025 bytes, checksum: 907abba7b19235b598e2c627358f9b82 (MD5) / Made available in DSpace on 2015-06-11T20:33:35Z (GMT). No. of bitstreams: 1 Dissertação -Daniely Amorim de Meireles.pdf: 13588025 bytes, checksum: 907abba7b19235b598e2c627358f9b82 (MD5) Previous issue date: 2014-01-24 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / The aim of this study was to evaluate, by means of tomographic exam, the occurrence and direction of apical deviation, capacity of centralization and percentage of area after root canal instrumentation with the Reciproc® and WaveOne® systems. Twenty-six mandibular molars with a degree of curvature of 20°≤40° and radius ≤10 mm, root length of 16 mm, apical diameter with reference to file K #15 and independent foramina were used. After embedment in self-polymerizing acrylic resin, the teeth were randomly distributed into two groups (n=13): WOG system – biomechanical preparation of mesial canals with WaveOne® and RG systems - biomechanical preparation of mesial canals with Reciproc® system. The apical deviation and its direction were evaluated using the formula D=(X1-X2)-(Y1-Y2). The capacity of centralization was analyzed by means of the formula CC=(X1-X2/Y1–Y2 or Y1– Y2/X1-X2), and the percentage increase in area was calculated from the difference between the area of the instrumented canal and that of the non-instrumented canal. RG presented the highest apical deviation values, however without statistically significant difference in comparison with WOG (P > .05). Both systems showed greater tendency towards transport in the mesial direction. None of the groups presented perfect centralization, with statistically similar values (p = 0.05). While the percentage increase in post instrumentation area presented no significant difference between the groups (P >.05). Both systems promoted minimal alteration in the root canal morphology. / O objetivo deste estudo foi avaliar por meio de exame tomográfico a ocorrência e direção do desvio apical, a capacidade de centralização e a porcentagem de aumento de área após instrumentação de canais radiculares com sistemas do Grupo Reciproc® (GR) e do Grupo WaveOne® (GWO). Vinte e seis molares inferiores com grau de curvatura de 20°≤40° e raio ≤10 mm, comprimento radicular de 16 mm, diâmetro apical referente a lima K #15 e forames independentes foram utilizados. Após inclusão em resina acrílica autopolimerizável, os dentes foram separados aleatoriamente em dois grupos (n=13): GWO - preparo biomecânico dos canais mesiais com sistema WaveOne® e GR - preparo biomecânico dos canais mesiais com sistema Reciproc®. O desvio apical e a sua direção foram avaliados a partir da fórmula D=(X1-X2)-(Y1-Y2). A capacidade de centralização foi analisada por meio da fórmula CC=(X1-X2/Y1–Y2 ou Y1–Y2/X1-X2), e o aumento percentual da área foi calculado a partir da diferença entre a área do canal instrumentado e não instrumentado. GR apresentou os maiores valores de desvio apical, no entanto, sem diferença estatisticamente significante em relação a GWO (P > .05). Ambos os sistemas proporcionaram maior tendência de transporte no sentido mesial. Ambos os grupos não apresentaram perfeita centralização, com valores similares estatisticamente (P >.05). Já o aumento percentual da área pós-instrumentação não apresentou diferença significante entre os grupos (P > .05). Ambos os sistemas promoveram alteração mínima da morfologia do canal radicular.

Objective: This retrospective longitudinal study attempts to determine the ontogenetic patterning of nasal septal deviation and if there is a relationship between a deviated septum and facial form growth and development. Methods: Nineteen females and twenty males were selected from the Iowa Facial Growth Study. Eighteen lateral cepalometric variables were analyzed and septal deviation was quantified using a percentage of deviation. A generalized Procrustes analysis was used to scale landmarks and generate principal components. Pearson correlation coefficients were used to analyze differences in shape. A Mann Whitney U-Test was used to analyze changes in septal deviation. Results: The first three principal components explained 56.23% of the variance. Only PC1 was significantly correlated with centroid size (r=0.82, P<0.0001). Mean percentage of septal deviation (0.620% ± 0.463%) was present at the youngest age group (3-4.9 years) and increased in each age group until adulthood, defined as over the age of 20 (0.991% ± 0.519). None of the first three principal components were found to be correlated to percentage of septal deviation. Conclusions: Nasal septal deviation has been found to increase in a longitudinal sample of subjects of northern European descent. Nasal septal deviation represents a disjunction in the growth of the nasal septum with the rest of the face. The amount and timing of nasal septal deviation that can cause nasal obstructions leading to vertical growth changes was not analyzed in this study and will require future study.

<p>A technique to detect deviations in sets of systems in a self-organized way is described in this work. System features are extracted to allow compact representation of the system. Distances between systems are calculated by computing distances between the features. The distances are then stored in an affinity matrix. Deviating systems are detected by assuming a statistical model for the affinities. The key idea is to extract features and and identify deviating systems in a self-organized way, using nonlinear techniques for the feature extraction. The results are compared with those achieved with linear techniques, (principal component analysis).</p><p>The features are computed with principal curves and an isometric feature mapping. In the case of principal curves the feature is the curve itself. In the case of isometric feature mapping is the feature a set of curves in the embedding space. The similarity measure between two representations is either the Hausdorff distance, or the Frechet distance. The deviation detection is performed by computing the probability of each system to be observed given all the other systems. To perform reliable inference the Bootstrapping technique was used.</p><p>The technique is demonstrated on simulated and on-road vehicle cooling system data. The results show the applicability and comparison with linear techniques.</p>

<p>The main idea of our work is the calibration parameters for the Heston stochastic volatility model. We make this procedure by using the OMXS30 index from the NASDAQ OMX Nordic Exchange Market. We separate our data into the stable period and high-volatility period on this Nordic Market. Deviation detection problem are solved using the Bayesian analysis of change-points. We estimate parameters of the Heston model for each of periods and make some conclusions.</p>

The question of how honesty is maintained in animal communication is a perplexing one, especially in the context of aggressive communication, in which the interests of signalers and receivers are opposed. Relevant information for receivers in aggressive interactions includes the fighting ability of the signaler and its likelihood of attack. Signalers may, however, benefit from manipulation of signals to exaggerate this information. To address questions of signal honesty, this dissertation investigates the use of a performance signal in the song of swamp sparrows (Melospiza georgiana). Performance signals are ones that are physically demanding to perform and that therefore reveal the signaler’s physical ability. The particular measure of vocal performance examined here is vocal deviation, which refers to the ability of birds to produce trilled songs approaching a performance boundary defined by the tradeoff between song trill rate (the rate at which elements of a song are repeated) and frequency bandwidth (the range of frequencies encompassed in a song). Three questions regarding the adaptive significance of vocal performance were investigated in the swamp sparrow 1) whether vocal performance is used as a signal in male-male communication, 2) whether vocal performance should be classified as an index signal of male quality, and 3) whether vocal deviation serves as a signal of aggressive intent. Results from four studies indicate that vocal performance plays a role in male-male signaling. Signalers appear to use vocal performance as a signal and receivers attend to differences in vocal performance. Evidence also indicates that vocal performance can be classified as an index signal, because males are constrained in their ability to produce high performance song and high vocal performance is correlated with aspects of male quality, such as age and size. Finally, this dissertation does not support classification of vocal performance as a signal of aggressive intent, because vocal performance fails to predict aggressive escalation.

The main idea of our work is the calibration parameters for the Heston stochastic volatility model. We make this procedure by using the OMXS30 index from the NASDAQ OMX Nordic Exchange Market. We separate our data into the stable period and high-volatility period on this Nordic Market. Deviation detection problem are solved using the Bayesian analysis of change-points. We estimate parameters of the Heston model for each of periods and make some conclusions.

Methods of efficient Monte-Carlo simulation when rare events are involved have been studied for several decades. Rare events are very important in the context of evaluating high quality computer/communication systems. Meanwhile, the efficient simulation of systems involving rare events poses great challenges. A simulation method is said to be efficient if the number of replicas required to get accurate estimates grows slowly, compared to the rate at which the probability of the rare event approaches zero. Despite the great success of the two mainstream methods, importance sampling (IS) and importance splitting, either of them can become inefficient under certain conditions, as reported in some recent studies. The purpose of this study is to look for possible enhancement of fast simulation methods. I focus on the ``level/phase process', a Markov process in which the level and the phase are two state variables. Furthermore, changes of level and phase are induced by events, which have rates that are independent of the level except at a boundary. For such a system, the event of reaching a high level occurs rarely, provided the system typically stays at lower levels. The states at those high levels constitute the rare event set. Though simple, this models a variety of applications involving rare events. In this setting, I have studied two efficient simulation methods, the rate tilting method and the adaptive splitting method, concerning their efficiencies. I have compared the efficiency of rate tilting with several previously used similar methods. The experiments are done by using queues in tandem, an often used test bench for the rare event simulation. The schema of adaptive splitting has not been described in literature. For this method, I have analyzed its efficiency to show its superiority over the (conventional) splitting method. The way that a system approaches a designated rare event set is called the system's large deviation behavior. Toward the end of gaining insight about the relation of system behavior and the efficiency of IS simulation, I quantify the large deviation behavior and its complexity. This work indicates that the system's large deviation behavior has a significant impact on the efficiency of a simulation method.

Methods of efficient Monte-Carlo simulation when rare events are involved have been studied for several decades. Rare events are very important in the context of evaluating high quality computer/communication systems. Meanwhile, the efficient simulation of systems involving rare events poses great challenges. A simulation method is said to be efficient if the number of replicas required to get accurate estimates grows slowly, compared to the rate at which the probability of the rare event approaches zero. Despite the great success of the two mainstream methods, importance sampling (IS) and importance splitting, either of them can become inefficient under certain conditions, as reported in some recent studies. The purpose of this study is to look for possible enhancement of fast simulation methods. I focus on the ``level/phase process', a Markov process in which the level and the phase are two state variables. Furthermore, changes of level and phase are induced by events, which have rates that are independent of the level except at a boundary. For such a system, the event of reaching a high level occurs rarely, provided the system typically stays at lower levels. The states at those high levels constitute the rare event set. Though simple, this models a variety of applications involving rare events. In this setting, I have studied two efficient simulation methods, the rate tilting method and the adaptive splitting method, concerning their efficiencies. I have compared the efficiency of rate tilting with several previously used similar methods. The experiments are done by using queues in tandem, an often used test bench for the rare event simulation. The schema of adaptive splitting has not been described in literature. For this method, I have analyzed its efficiency to show its superiority over the (conventional) splitting method. The way that a system approaches a designated rare event set is called the system's large deviation behavior. Toward the end of gaining insight about the relation of system behavior and the efficiency of IS simulation, I quantify the large deviation behavior and its complexity. This work indicates that the system's large deviation behavior has a significant impact on the efficiency of a simulation method.