Finding a common language in describing and interpreting multivariate data associated with rehabilitation and disturbance ecology, has became a major challenge. The main objective of this study is to find and evaluate mathematical models to describe ecosystem change based on selected indicators of change. Existing data from a previous rehabilitation project on Hendrina Power Station (Mpumalanga, South Africa) was used as a database for this study and this study aims to report on the development of models concentrating on radar graphs and a model based on matrix mathematics. The main groups of organisms selected for the construction of models, were vegetation, soil mesofauna and ant species. The datasets were limited to some indicative species and their mean abundances were determined. The grids that were used were randomly chosen and the models were constructed. Radar graphs were constructed to model the suite of species identified, through a sensitivity analysis, to indicate possible rehabilitation success over time and was applied to the different rehabilitation ages. The surface areas under the radar graphs were determined and compared for the different rehabilitation ages in the same year of survey. Correlation graphs were drawn between the surface area and the rehabilitation ages. These graphs did not indicate much relevance in indicating rehabilitation success, but the radar graphs proved to be good indicators of change in abundance of the selected species over time. iv The vegetation species, Eragrostis curvula, was the only species that showed a strong significant positive relationship with rehabilitation age and could be considered a good rehabilitation species and indicator of rehabilitation success. After the evaluation of this model, Eragrostis curvula, and two additional ant species, Tetramorium setigerum and Lepisiota laevis, were added. These species that were added, showed an increase in abundance over time, as found in a previous study. These radar graphs also did not indicate much relevance and it can be concluded that the radar graphs can only be used for a visual representation of the changes in abundance of the relevant species over time. This study also refers to a matrix model. This model focused on the interactions between the different variables selected. The percentage carbon in the soil were also added to the list of species. Model fitting graphs were constructed and correlations were drawn between the species that had significant values in the interaction table. This model could be useful for future studies, but more data and replication is necessary, over a longer period of time. This will serve to eliminate possible shortcomings of the model. / Thesis (M. Environmental Science (Biodiversity and Conservation Biology))--North-West University, Potchefstroom Campus, 2007.

The thesis discusses the channel modelling and relay techniques in powerline communications (PLC) which is considered as a promising technology for the Smart Grid communications, Internet access and home area network (HAN). In this thesis, the statistical PLC channel characteristics are investigated, a new statistical channel modelling method is proposed for the in-door PLC. Then a series of the relay protocols are suggested for the broadband communications over power grid. The statistical channel modelling method is proposed to surmount the limits of the traditional deterministic PLC channel models such as multipath model and transmission line model. To develop the channel model, the properties of the multipath magnitudes, interval between the paths, cable loss and the channel classification are investigated in detail. Then, each property is described by statistical distribution or formula. The simulation results show that the statistical model can describe the PLC channels as accurate as deterministic models without the topology information which is a time-consuming work for collecting. The relay transmission is proposed to help PLC adapting the diverse application scenarios. The protocols covers the main relay aspects which include decode/amplify forwarding, single/ multiple relay nodes, full/half duplex relay working mode. The capacity performance of each protocol is given and compared. A series of the facts which improve the performance of the PLC networks are figured out according to simulation results. The facts include that the decode-and-forward is more suitable for the PLC environment, deviation or transforming station is better location for placing relay node and full duplex relay working mode help exploiting the capacity potential of the PLC networks. Some future works are pointed out based on the work of statistical channel model and relay. In the last part of this thesis, an unit based statistical channel model is initialled for adapting various PLC channel conditions, a more practical relay scenario which contains multiple data terminals is proposed for approaching the realistic transmission scenario. At last, the relay for the narrowband PLC Smart Grid is also mentioned as future research topic.

Master of Science / Department of Electrical and Computer Engineering / Caterina Maria Scoglio / Japanese Encephalitis (JE) is a vector-borne disease transmitted by mosquitoes and maintained in birds and pigs. An interconnected network model is proposed to examine the possible epidemiology of JE in the USA. Proposed JE model is an individual-level network model that explicitly considers the feral pig population and implicitly considers mosquitoes and birds in specific areas of Florida, North Carolina, and South Carolina. The virus transmission among feral pigs within a small geographic area (<60 sq mi areas) are modeled using two network topologies— fully connected and Erdos-Renyi networks. Connections between locations situated in different states (interstate links) are created with limited probability and based on fall and spring bird migration patterns. Simulation results obtained from the network models support the use of the Erdos-Renyi network because maximum incidence occurs during the fall migration period which is similar to the peak incidence of the closely related West Nile virus (WNV), another virus in the Japanese Encephalitis group (Flaviviridae) that is transmitted by both birds and mosquitoes. Simulation analysis suggested two important mitigation strategies: for low mosquito vectorial capacity, insecticidal spraying of infected areas reduces transmission and limits the outbreak to a single geographic area. Alternatively, in high mosquito vectorial capacity areas, birds rather than mosquitoes need to be removed/controlled.

Wind power is one of the world fastest growing electricity sources in the world and has since 1990 roughly been doubling in capacity every four years. The industry boom and the followed technology development has made the clean and inexhaustible wind energy, price competitive with fossil fuels, making wind power a sustainable tool to address climate change. The European and the North American market was long the dominant wind power markets in the world. Due to the rapid development in emerging economies a change in both market and turbine manufactures has occurred, making Asia the largest market in the world, housing five of the top ten wind power manufactures in 2015. This thesis focus on business model research in Envision Energy, a Chinese wind turbine manufacture, which in short time has gone from being a new entrant to one of the top manufactures in the world, focusing on quality and technology innovation. The research combines primary data from a semi structured interview with secondary data about Envision, the wind industry and the Chinese wind industry. By exploring Envisions business model and the context they operate in, this study found some key factors for Envision successful business model and drivers to enter the international market. As a Chinese wind turbine manufacture, Envisions have done many things that stands out compared to their domestic competitors. Already in their initial stage they set out to establish international innovation centers to be present in the global technology hot spots and be up to date with the newest technology and solutions. Their global presence was made possible by requiting industry experts from competitors, which also came to Envision with the necessary technical know-how, market knowledge and industry networks. Focusing on technical innovation and emphasizing on quality, Envisions has developed new innovative turbine and software solutions, using globally recognized suppliers instead of the domestic suppliers mostly used by their Chinese competitors. Envision has become recognized as quality wind turbine provider in the Chinese market who takes system integrated life cycle approach to lower the cost of energy. With their vision of revolutionize the energy sector on a global scale, Envision recently entered the international space on three continents, with a generic internationalization strategy. The human resources are the core of Envisions business model and are the underlying factor of their rapid success in the Chinese market as they managed to provide reliable turbines when their competitors struggled. With the human resources Envision could establish themselves internationally short after their foundation. The combined knowledge from the international organization enabled them to develop innovative wind turbine solutions, while emphasizing on quality. With a system integrated life cycle approach Envision focus to lower the cost energy with wind turbine solutions and a software system which can enhance asset life and performance on any renewable energy asset. The vision to make an impact on the energy sector has been the main driver behind Envisions internationalization, even though external drivers are imminent.

In the first part of the thesis, theoretical uncertainties of jet cross-section have been calculated for proton-proton collision at the center of mass energy of 8 TeV. For jet identification the anti-kT algorithm with scale parameter R = 0.6 was used. As the calculations showed, the major contribution to the total theoretical uncertainty comes from the uncertainty of parton distribution function parameters. In the second part of the thesis, the angular distribution of dijet events produced in proton-proton collisions at the center of mass energy 8 TeV were simulated using Pythia 8 Monte Carlo event generator. New physics model of quark compositeness that should manifest itself by quark contact interaction was studied using angular distribution of dijet events. Three angular variables were discussed and these variables were used to calculate 95% CL lower limit on contact interaction scale. The results were compared and it emerged that the sensitivity to contact interaction signals varies for these variables.

Model formulas are the standard approach for specifying the variables in statistical models in the S language. Although being eminently useful in an extremely wide class of applications, they have certain limitations including being confined to single responses and not providing convenient support for processing formulas with multiple parts. The latter is relevant for models with two or more sets of variable, e.g., regressors/instruments in instrumental variable regressions, two-part models such as hurdle models, or alternative-specific and individual-specific variables in choice models among many others. The R package Formula addresses these two problems by providing a new class "Formula" (inheriting from "formula") that accepts an additional formula operator | separating multiple parts and by allowing all formula operators (including the new |) on the left-hand side to support multiple responses. / Series: Research Report Series / Department of Statistics and Mathematics

The calibration application named ExCalibre was developed at Technical University in Prague, Faculty of Civil Engineering. This application can automatically process experimental data and create set of parameters of hypoplastic models which are designed for saturated clays or sands. The aim of this master thesis was to support development of application for calibration with testing it on real experimental data sets. Automatic calibration of these data sets was compared with calibration by hand for identical data. The development of the application and main phase of testing took place in two stages, where the main calibration errors of calibration application were identified. After the final testing of application where the minor bugs and errors were overcome a user-friendly web application (soilmodel.com/excalibre/) was introduced. This final testing has gone beyond this thesis. The results from the main phases of testing are discussed in this thesis as well as the description of database of fine-grained and coarse-grained samples which were used to testing of application. Knowing the calibration of the model is crucial for its using, you can find description of the used constitutive models in this thesis, which are used in the calibration application, as well as a description of procedure for...

Le formalisme des réseaux de Petri hybrides fonctionnels, notés HFPN pour Hybrid Functional Petri Nets en anglais, a démontré sa capacité à simuler les systèmes biologiques. L’inconvénient d’un formalisme aussi expressif est la difficulté d’exécuter des vérifications de propriétés dynamiques. Dans cette thèse, nous proposons une procédure de model-checking pour les réseaux de Petri hybrides temporisés, notés THPN pour Timed Hybrid Petri Nets en anglais, une sous-classe des HFPN. Cette procédure est basée sur la traduction du modèle THPN et de la propriété étudiée en automates temps-réel. Ceci est alors appliqué pour modéliser les régulations responsables de la métamorphose amphibienne. / The formalism of Hybrid Functional Petri Nets (HFPN) has proved its convenience for simulating biological systems. The drawback of the noticeable expressiveness of HFPN is the difficulty to perform formal verifications of dynamical properties. In this thesis, we propose a model-checking procedure for Timed Hybrid Petri Nets (THPN), a sub-class of HFPN. This procedure is based on the translation of the THPN model and of the studied property into real-time automata. It is applied to model regulations responsible for amphibian metamorphosis.

Model Predictive Control (MPC) refers to a class of algorithms that optimize the future behavior of the plant subject to operational constraints [46]. The merits of the class algorithms include its ability to handle imposed hard constraints on the system and perform on-line optimization. This thesis investigates design and implementation of continuous time model predictive control using Laguerre polynomials and extends the design ap- proaches proposed in [43] to include intermittent predictive control, as well as to include the case of the nonlinear predictive control. In the Intermittent Predictive Control, the Laguerre functions are used to describe the control trajectories between two sample points to save the com- putational time and make the implementation feasible in the situation of the fast sampling of a dynamic system. In the nonlinear predictive control, the Laguerre polynomials are used to describe the trajectories of the nonlinear control signals so that the reced- ing horizon control principle are applied in the design with respect to the nonlinear system constraints. In addition, the thesis reviews several Quadratic Programming methods and compares their performances in the implementation of the predictive control. The thesis also presents simulation results of predictive control of the autonomous underwater vehicle and the water tank.

We discuss the target space pseudoduality in supersymmetric sigma models on symmetric spaces. We first consider the case where sigma models based on real compact connected Lie groups of the same dimensionality and give examples using three dimensional models on target spaces. We show explicit construction of nonlocal conserved currents on the pseudodual manifold. We then switch the Lie group valued pseudoduality equations to Lie algebra valued ones, which leads to an infinite number of pseudoduality equations. We obtain an infinite number of conserved currents on the tangent bundle of the pseudodual manifold. Since pseudoduality imposes the condition that sigma models pseudodual to each other are based on symmetric spaces with opposite curvatures (i.e. dual symmetric spaces), we investigate pseudoduality transformation on the symmetric space sigma models in the third chapter. We see that there can be mixing of decomposed spaces with each other, which leads to mixings of the following expressions. We obtain the pseudodual conserved currents which are viewed as the orthonormal frame on the pullback bundle of the tangent space of G tilde which is the Lie group on which the pseudodual model based. Hence we obtain the mixing forms of curvature relations and one loop renormalization group beta function by means of these currents. In chapter four, we generalize the classical construction of pseudoduality transformation to supersymmetric case. We perform this both by component expansion method on manifold M and by orthonormal coframe method on manifold SO(M). The component method produces the result that pseudoduality tranformation is not invertible at all points and occurs from all points on one manifold to only one point where riemann normal coordinates valid on the second manifold. Torsion of the sigma model on M must vanish while it is nonvanishing on M tilde, and curvatures of the manifolds must be constant and the same because of anticommuting grassmann numbers. We obtain the similar results with the classical case in orthonormal coframe method. In case of super WZW sigma models pseudoduality equations result in three different pseudoduality conditions; flat space, chiral and antichiral pseudoduality. Finally we study the pseudoduality tansformations on symmetric spaces using two different methods again. These two methods yield similar results to the classical cases with the exception that commuting bracket relations in classical case turns out to be anticommuting ones because of the appearance of grassmann numbers. It is understood that constraint relations in case of non-mixing pseudoduality are the remnants of mixing pseudoduality. Once mixing terms are included in the pseudoduality the constraint relations disappear.