The aim of this thesis is to describe the most frequent models describing population dynamics and then to perform some numerical experiments in the MATLAB environment. These simulations should validate our theoretical results. The models are sorted from the basic models to the most complicated and are divided into the models which describe dynamics of one population and models of coexistence of two biological species. The master's thesis icludes also a program for drawing graphs and trajectories of solutions of models described in this thesis including a description of this MATLAB program.

The aim of this thesis is to assemble simplified computational 3D model for straw grate combustion, based on data provided by detailed computational 1D model. This thesis is organized as follows. Firstly, current state of CFD grate combustion modelling is described. The main body of this thesis is focused on creation simplified 3D model, which includes pressure losses calculation, aproximation of data provided by outcomes of detailed 1D model and analysis of heat transfer during combustion process. Simulation results dealing with radiation heat transfer and heat conductivity are included in conclusion.

Les multiprocesseurs et microprocesseurs multicœurs modernes mettent en oeuvre des modèles mémoires dits faibles ou relâchés, dans dans lesquels l'ordre apparent des opérations mémoire ne suit pas la cohérence séquentielle (SC) proposée par Leslie Lamport. Tout programme concurrent s'exécutant sur une telle architecture et conçu avec un modèle SC en tête risque de montrer à l'exécution de nouveaux comportements, dont certains sont potentiellement des comportements incorrects. Par exemple, un algorithme d'exclusion mutuelle correct avec une sémantique par entrelacement pourrait ne plus garantir l'exclusion mutuelle lorsqu'il est mis en oeuvre sur une architecture plus relâchée. Raisonner sur la sémantique de tels programmes s'avère très difficile. Par ailleurs, bon nombre d'algorithmes concurrents sont conçus pour fonctionner indépendamment du nombre de processus mis en oeuvre. On voudrait donc pouvoir s'assurer de la correction d'algorithmes concurrents, quel que soit le nombre de processus impliqués. Pour ce faire, on s'appuie sur le cadre du Model Checking Modulo Theories (MCMT), développé par Ghilardi et Ranise, qui permet la vérification de propriétés de sûreté de programmes concurrents paramétrés, c'est-à-dire mettant en oeuvre un nombre arbitraire de processus. On étend cette technologie avec une théorie permettant de raisonner sur des modèles mémoires faibles. Le résultat ce ces travaux est une extension du model checker Cubicle, appelée Cubicle-W, permettant de vérifier des propriétés de systèmes de transitions paramétrés s'exécutant sur un modèle mémoire faible similaire à TSO. / Modern multiprocessors and microprocesseurs implement weak or relaxed memory models, in which the apparent order of memory operation does not follow the sequential consistency (SC) proposed by Leslie Lamport. Any concurrent program running on such architecture and designed with an SC model in mind may exhibit new behaviors during its execution, some of which may potentially be incorrect. For instance, a mutual exclusion algorithm, correct under an interleaving semantics, may no longer guarantee mutual exclusion when implemented on a weaker architecture. Reasoning about the semantics of such programs is a difficult task. Moreover, most concurrent algorithms are designed for an arbitrary number of processus. We would like to ensure the correctness of concurrent algorithms, regardless of the number of processes involved. For this purpose, we rely on the Model Checking Modulo Theories (MCMT) framework, developed by Ghilardi and Ranise, which allows for the verification of safety properties of parameterized concurrent programs, that is to say, programs involving an arbitrary number of processes. We extend this technology with a theory for reasoning about weak memory models. The result of this work is an extension of the Cubicle model checker called Cubicle-W, which allows the verification of safety properties of parameterized transition systems running under a weak memory model similar to TSO.

Philosophiae Doctor - PhD / One of the assumptions of conventional regression analysis is I that the parameters are constant over all observations. It has often been suggested that this may not be a valid assumption to make, particularly if the econometric model is to be used for economic forecasting0 Apart from this it is also found that econometric models, in particular, are used to investigate the underlying interrelationships of the system under consideration in order to understand and to explain relevant phenomena in structural analysis. The pre-requisite of such use of econometrics is that the regression parameters of the model is assumed to be constant over time or across different crosssectional units.

The influence of the distributor configuration on the mass transfer and bubble sizes in a 2-D FBR was studied for two types of distributor configurations: <ul><li> A novel multi-vortex (MV) distributor with tuyéres directed vertically and horizontally at different heights. </li><li> A standard perforated plate distributor (baseline). </li></ul> The ozone decomposition reaction over FCC catalyst was used as an indirect meas-ure of the interphase mass transfer in the bed. The ranged between 0.1 m/s and 0.35 m/s, with air as a fluidizing medium at ambient conditions. The MV distributor displayed a significant improvement in the conversion cies (χmeasured / χPFR). For all velocities an improvement of between 0% and 30% was measured (average improvement of 14.7%). At Uo ≤ 0.2 m/s the improvement distributed evenly about the mean improvement, with a minimum improvement of 10%. The Uc for the respective distributors were determined using absolute pressure fluctuations (baseline distributor) and visual observations (MV distributor) and it was found that the Uc for the MV distributor was lower than that for the baseline: <ul><li> Uc Baceline = 0.30 m/s.</li><li> Uc MV distributor = 0.25 m/s.</li></ul> The decrease in Uc indicated that the MV distributor induces faster onset of turbulent behaviour in the FBR which negates interphase mass transfer limitations in the FBR. The bubble sizes were measured visually and compared to a pressure signal decomposition technique. The bubble size growth for the MV distributor was estimated at .14 times that of the baseline. Two models were compared to the experimental results, the Kunii-Levenspiel three-phase model and the Thompson generalized bubble-turbulent model. The fitting parameters showed that the mass transfer for the MV distributor is significantly larger than that of the baseline. In addition the MV distributor decreased the axial dispersion in the FBR as Uo → Uoo, which improved the reactor performance to that of an ideal PFR. This phenomenon was observed at Uo > 0.33 m/s. / Dissertation (MEng)--University of Pretoria, 2011. / Chemical Engineering / unrestricted

Health care represents an increasing proportion of global consumption. We discuss ways to model health care utilization on an individual basis. We present a probabilistic, generative model of utilization. Leveraging previously observed utilization levels, we learn a latent structure that can be used to accurately understand risk and make predictions. We evaluate the effectiveness of the model using data from a large population.

Forecasting Election Results in the Czech Republic Kateřina Doskočilová In this thesis, a forecasting model for the 2017 legislative election in the Czech Republic is built. As the Czech Republic has a multi-party system, the outcomes of the model are the expected vote shares for each party. There are two types of forecasts calculated. Firstly, a poll-based forecast using a dynamic linear model and Kalman filter to weigh the information in the polls. Secondly, the prices on betting markets are translated into probabilistic forecasts for the expected vote shares. This is a novel approach as prediction markets were previously used to forecasts only the probabilities of winning an election. Finally, the two types of forecasts are combined into one and weighed by their variance. Comparing the forecasts, we conclude that the betting market is able to predict the exact vote shares the most accurately right before the election.

Traditional macroeconomics believes that confidence is not the main cause of economic fluctuations, but when faced with financial crises, monetary authorities still emphasize the role of stabilizing confidence. Although people generally agree that confidence is an important part of the transmission of macro-policies to micro- individuals, there is neither empirical evidence support nor corresponding mechanism research. This thesis attempts to answer the following questions: Does business confidence affect the effectiveness of monetary policy? Does business confidence have the same impact on monetary policy in different economic periods? This thesis first constructed a structural vector auto-regression (SVAR) model to test the role of business confidence in the transmission of monetary policy in the euro area. The empirical results show that expansionary monetary policy can effectively boost business confidence while stimulating output growth. In addition, this thesis extends the model by introducing share prices and exchange rates to investigate the role of these two important to the monetary transmission mechanism, concluding that business confidence plays a strong role in interest rate transmission and a weaker role in the transmission of asset prices and exchange rates. Subsequently, in order to...

Magister Educationis - MEd / Writing is an important skill throughout learners’ schooling trajectory because it is through writing that learners need to situate meaning and sense-making across the curriculum. Writing proficiency becomes even more important when learners access tertiary studies. Yet studies suggest that most students struggle with academic writing. Various authors suggest that writing has not been taught appropriately especially in secondary schooling contexts in South Africa and that writing becomes even more daunting for Second Language speakers of English when they reach tertiary education. There is abundant literature on students’ challenges with academic writing and ways to address academic writing challenges but the use of digital storytelling in relation to academic writing development is recent and distinctively underexplored in the literature. In this study, I seek to explore the potential that digital storytelling has in the teaching of undergraduate academic writing skills. I will focus on first year students' academic writing skills, how they are taught currently and how technology in the form of digital storytelling can help first year students improve their academic writing skills. The theoretical framework for the study is largely based on the New Literacies Studies which is championed by members of the New London Group such as Street and Street (1984) Lea and Street (2006) among others. The theoretical framework will draw on the notion of literacy as social practice rather than a set of reading and writing skills which explains why educators need to find new ways of teaching academic writing skills. I use semiotics and multimodality as a foundational concept for using digital storytelling in academic writing. That is because semiotics and multimodality further support the idea that literacy goes beyond words but that audio and visual elements are also part of learning and can help engage students in their academic work. The main aim of this proposed research is to explore both students and lecturer practices of digital literacies in the teaching and learning of academic writing at The Cape Peninsula University of Technology (CPUT).

Magister Educationis - MEd / Writing is an important skill throughout learners’ schooling trajectory because it is through writing that learners need to situate meaning and sense-making across the curriculum. Writing proficiency becomes even more important when learners access tertiary studies. Yet studies suggest that most students struggle with academic writing. Various authors suggest that writing has not been taught appropriately especially in secondary schooling contexts in South Africa and that writing becomes even more daunting for Second Language speakers of English when they reach tertiary education. There is abundant literature on students’ challenges with academic writing and ways to address academic writing challenges but the use of digital storytelling in relation to academic writing development is recent and distinctively underexplored in the literature. In this study, I seek to explore the potential that digital storytelling has in the teaching of undergraduate academic writing skills. I will focus on first year students' academic writing skills, how they are taught currently and how technology in the form of digital storytelling can help first year students improve their academic writing skills. The theoretical framework for the study is largely based on the New Literacies Studies which is championed by members of the New London Group such as Street and Street (1984) Lea and Street (2006) among others. The theoretical framework will draw on the notion of literacy as social practice rather than a set of reading and writing skills which explains why educators need to find new ways of teaching academic writing skills. I use semiotics and multimodality as a foundational concept for using digital storytelling in academic writing. That is because semiotics and multimodality further support the idea that literacy goes beyond words but that audio and visual elements are also part of learning and can help engage students in their academic work. The main aim of this proposed research is to explore both students and lecturer practices of digital literacies in the teaching and learning of academic writing at The Cape Peninsula University of Technology (CPUT).