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In wireless networking, receivers are typically assumed to be utilizing single-user decoding. Still, for more than twenty years we know that we can take advantage of interference by multi-user decoding. The Interference Cancellation (IC) technique has, of late, gained interest in the wireless networking context. Previous works [3] have shown considerable potential gains by leveraging optimal collaborative rate control to enable IC, focusing on the low Signal-to-Noise Ratio (SNR) regime. Here, we present centralized and distributed rate control algorithms, enabling IC, to increase system throughput. We consider a system where the receivers can apply multi-user decoding to perform IC and the rates are provided by a step-wise function of the Signal to Interference-and-Noise Ratio (SINR), in realistic conditions. We conduct a thorough simulation study comparing the proposed algorithms using two IC techniques, and deliver results that indicate significant system throughput gains.

The current research was undertaken to assess if the prices in the South African capital market imply a risk free rate that is not equal to the theoretical risk free rate. The research was conducted by means of a literature review and desktop-research-based analysis of the market price based yield curve. The literature review was conducted to establish the importance of the risk free rate in the financial systems dynamics. The literature review highlighted that all the portfolio theories and performance-measure indicators have the risk free rate at the core of their methodology. This implies that the risk free rate is the most important concept that determines the market demand of different instruments. Next, a comparison has been drawn between the BESA published bond yield curve and a market-price-based yield curve developed by the researcher. The findings establish that the market price derived risk free rate is higher than the theoretical risk free rate. It was also found that the shape of the yield curve is different from the BESA projected yield curve, and that it is indicative of future problems in the South African capital market. The implications of investors‟ perceptions of the higher risk free rate are discussed and it is revealed that the foreign investors consider the country risk and the default risk associated with the South African government as higher than the BESA may perceive it to be. / Thesis (MCom (Risk Management))--North-West University, Vaal Triangle Campus, 2013

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Knowledge of the relationship between rate of nitrification and nitrous oxide (N2O) emission, and between cumulative nitrification and N2O emission is important for developing N2O emission mitigation strategies. Gross nitrification and N2O from nitrification were determined using 15N labelling of inorganic N. N-Serve was added to delay nitrification and results showed an increase in rate of N2O emission with that of apparent nitrification in absence of N-Serve, but there was no relation in its presence. Same amount of cumulative N2O was emitted for same amount of nitrogen (N) apparently nitrified, regardless of N-Serve addition. There was no relation between N2O emission attributed to nitrification and gross nitrification with and without N-Serve. Again, same amount of cumulative N2O was emitted for same amount of gross nitrified N, regardless of N-Serve addition. These results imply that the amount of N nitrified dictates eventual cumulative N2O emitted, regardless of rate of nitrification. / February 2017

Dissertation submitted in compliance with the requirements for Masters Degree in Technology in the Department of Electrical Engineering, Technikon Natal, 2000. / The purpose of this study is the development of an affordable computer-based electrocardiogram, heart rate and temperature monitoring system, that would complement those that are available on the market and contribute to the reduction of the shortage of these medical instruments in South African hospitals and clinics. Electrocardiogram (ECG) refers to the graph that results from time versus voltage in a patient's chest. It reflects the rhythmic activity of the heart. For this reason the electrocardiogram has a diagnostic value that can be used by medical personnel to examine the biological (hence, clinical) behavior of the heart. The electrocardiogram can also be used to get the heart rate. This thesis explained how to acquire ECG signals from the patient and also how to achieve a cheaper way of providing galvanic isolation, which is required for sensors that are attached to the human body. It also explains computer interfacing using the parallel port and computer-based processing of these ECG signals to determine the instantaneous value of the heart rate and also to reduce the interference that contaminates these signals. In reducing interference, the performance of traditional IIR notch and adaptive filters, as noise cancelers, has been analyzed and compared. Least Mean Squares (LMS) and Normalized Least Mean Squares (NLMS) algorithms are the two algorithms that were considered in this study for adaptive noise canceling and their performance is evaluated and is compared based on their convergence rate, complexity and noise reduction. / M

The elemental composition within structured insect populations was tested by creating a new method to analyze how variables (survival, growth and fecundity) within a population matrix could potentially affect the stoichiometric regime of a structured population at steady state. This was done by focusing on if the growth rate hypothesis, which states that there is a linear relationship between an individual growth rate and the percent of phosphorus within the individual, works at a population level. This was analyzed by creating and combining two matrices: the matrix-population containing the variables and a matrix containing the element phosphorus and dry weight. Data from a beetle species, Chrysomela tremulae F., was used as a guideline to create eight stoichiometric generic populations, where survival, growth and fecundity were tested in each of the eight generic populations. The results showed deviations from the growth rate hypothesis, suggesting that the hypothesis does not always work within structured populations. However, more research is needed to predict exactly how this hypothesis works in populations. Overall, this new method for analyzing stoichiometry within structured populations is a useful analytical tool, but there is a need for analyzing the results from these models in a more efficient way.

The purposes of this study were (1) to determine the relationship between recitation in the classroom and changes in the cardiac rate, (2) to determine the effects on cardiac rate of anticipation of recitation and tests, (3) to determine the effects on cardiac rate of compliments and assurance directed toward students by the teacher, and (4) to determine the effects on the cardiac rate of verbal threats and ridicule.