The "global" financial crisis (GFC) emerged during 2008 and it was mainly triggered by the sub-prime mortgage crisis (SMC) in the United States of America. The main aims of this thesis is to conduct an econometric analysis of the financial crisis and household savings in South Africa and also to provide a rationale that will facilitate a policy attention on Domestic Resource Mobilisation (DRM) through household savings. The study uses quarterly time series data for the period 199401 to 201102 obtained on-line from the South African Reserve Bank (SARB). The research is based on the Keynesian saving function, which is a complement of the consumption function. The model will be estimated by using a cointegrating vector autoregressive (CVAR) framework, which allows for endogeneity of the regressors. To check robustness on the cointegration results, the study employs the second empirical technique based on Generalized Impulse Response Function (GIRF) analysis and Variance Decomposition. The regression equation of household savings is expressed as a function of household disposable income, household debt to disposable income, real GOP, interest rate, inflation rate and foreign savings. The variables are tested for the presence of a unit root by the application of the Augmented Dickey-Fuller (AOF), Phillips-Perron (PP) Kwiatkowski, Phillips, Schmidt and Shin (KPSS) tests. The findings of the study are that all variables have unit roots. The cointegration model emphasises the presence of a long run equilibrium relationship between dependent and independent variables. The CVAR reveals the short run of the dynamic household savings model. Taking this into consideration, the study concludes that household debt has a huge influence on the level of household savings. The econometric analysis also revealed that household savings in South Africa actually improved during the period associated with the GFC. It could be postulated that South African households responded to their deteriorating financial situations by reducing their average spending and increasing their savings. Variance decomposition analysis revealed that 'own shocks' constitute the predominant source of variations in household saving therefore household savings can be explained by the disturbances in macroeconomic variables in the study. The study recommends the promotion of household savings and economic growth in order to reduce the dependence of South Africa on foreign savings. DRM is therefore enhanced by a higher level of household savings, which can facilitate higher levels of investment and economic growth. / Thesis (PhD (Economics) North-West University, Mafikeng Campus, 2012

In system identification, different methods are often classified as parametric or non-parametric methods. For parametric methods, a parametric model of a system is considered and the model parameters are estimated. For non-parametric methods, no parametric model is used and the result of the identification is given as a curve or a function. One of the non-parametric methods is the impulse response analysis. This approach is dynamic simulation. This thesis introduces a new paradigm for dynamic simulation, called impulse-based simulation. This approach is based on choosing a Dirac function as input, and as a result, the output will be equal to the impulse response. However, a Dirac function cannot be realized in practice, and an approximation has to be used. As a consequence, the output will deviate from the impulse response. Once the impulse response is estimated, a parametric model can be fitted to the estimation. This thesis aims to determine the parameters in a parametric model from an estimated impulse response. The process of investigating the models is a critical aspect of the project. Correlation analysis is used to obtain the weighting function from the estimates of covariance functions. Later, a relation formed between the parameters and the estimates (obtained by correlation analysis) in the form of a linear system of equations. Furthermore, simulations are carried out using Monte Carlo for investigating the properties of the two step approach, which involves in correlation analysis to find h-parameters and least squares and total least squares methods to solve for the parameters of the model. In order to evaluate the complete capability of the approach to the noise variation a study of signal to noise ratio and mean, mean square error and variances of the estimated parameters is carried out. The results of the Monte Carlo study indicate that two-step approach can give rather accurate parameter estimates. In addition, the least squares and total least squares methods give similar results.

Electronic dispersion compensation (EDC) of intermodal dispersion on short multimode fiber (MMF) links operating at 40 Gb/s is investigated through system level simulations and the design of two analog integrated circuit (IC) equalizers. System simulations using worst-case MMF link models show the effectiveness of a 2-tap baud spaced finite impulse response (FIR) equalizer for 40-m links, and a second-order Tbaud/2 infinite impulse response (IIR) equalizer for 50-m links. An IIR filter topology suitable for IC implementation with double loops and multiple delay sections was developed. The 2-tap FIR and the IIR equalizer are implemented in UMC 0.13-um and STM 90-nm CMOS processes respectively. Measurements demonstrate the FIR and IIR equalizing 38-Gb/s and 30-Gb/s cable channels respectively. To the author's knowledge, the double-loop multi-delay IIR equalizer is the first integrated traveling-wave equalizer utilizing poles as a means of frequency boosting, contrasting the conventional FIR technique of utilizing zeros.

Electronic dispersion compensation (EDC) of intermodal dispersion on short multimode fiber (MMF) links operating at 40 Gb/s is investigated through system level simulations and the design of two analog integrated circuit (IC) equalizers. System simulations using worst-case MMF link models show the effectiveness of a 2-tap baud spaced finite impulse response (FIR) equalizer for 40-m links, and a second-order Tbaud/2 infinite impulse response (IIR) equalizer for 50-m links. An IIR filter topology suitable for IC implementation with double loops and multiple delay sections was developed. The 2-tap FIR and the IIR equalizer are implemented in UMC 0.13-um and STM 90-nm CMOS processes respectively. Measurements demonstrate the FIR and IIR equalizing 38-Gb/s and 30-Gb/s cable channels respectively. To the author's knowledge, the double-loop multi-delay IIR equalizer is the first integrated traveling-wave equalizer utilizing poles as a means of frequency boosting, contrasting the conventional FIR technique of utilizing zeros.

The “green agenda” combined with highway congestion has accelerated the demand for increased freight and passenger travel on the world’s railways. These increases have driven demand for more efficient and rapid investigation of trackbed ballast. Network Rail and other rail infrastructure operators spend significant financial sums on inspecting, tamping, adjusting, cleaning, and replacing trackbed ballast. Such maintenance is often to the detriment of normal network operation. Industry requires a method of ballast evaluation that is non-intrusive, cheap, can appraise long stretches of track in a short period of time, and give a fingerprinting result from which time-to-maintenance can be calculated and planned. Thus, the aim was to develop evaluation methods using non-destructive testing techniques. A 10-year old full-scale trackbed composed of variously fouled ballast was re-visited and used for experimentation. The condition of the ballast was calculated using the Ionescu Fouling Index. Earlier research at the University of Edinburgh enabled researchers worldwide to characterise ballast using ground penetrating radar (GPR). This research was repeated, validated and taken forward in a series of GPR experiments on the trackbed using a range of antennas from 500MHz to 2.6GHz. New "scatter" metrics were developed to determine ballast condition from the GPR waveforms. These metrics were then used to predict the Ionescu Fouling Index with a correlation coefficient greater than 0.9. One of the current approaches to evaluating the stiffness of railway ballast is to use a Falling Weight Deflectometer (FWD). The viability of using a Prima 100 mini-FWD on railways to measure stiffness was determined and deemed to be ineffective on ballast. The applicability of the impulse response technique on railways was determined. An instrumented hammer was used to excite the ballast, with a geophone measuring the response. The Frequency Response Function of this was successfully correlated with the Ionescu Fouling Index with a correlation coefficient also greater than 0.9. Finally, using GPR data and measured stiffness data collected by Banverket, Sweden, a numerical model to successfully relate radar responses to stiffness was developed.

The main focus of the research presented within this thesis is, as the title suggests, binaural spatialization. Binaural technology and, especially, the binaural recording technique are not particu-larly recent. Nevertheless, the interest in this technology has lately become substantial due to the increase in the calculation power of personal computers, which started to allow the complete and accurate real-time simulation of three-dimensional sound-fields over headphones. The goals of this body of research have been determined in order to provide elements of novelty and of contribution to the state of the art in the field of binaural spatialization. A brief summary of these is found in the following list: • The development and implementation of a binaural spatialization technique with Distance Simulation, based on the individual simulation of the distance cues and Binaural Reverb, in turn based on the weighted mix between the signals convolved with the different HRIR and BRIR sets; • The development and implementation of a characterization process for modifying a BRIR set in order to simulate different environments with different characteristics in terms of frequency response and reverb time; • The creation of a real-time and offline binaural spatialization application, imple-menting the techniques cited in the previous points, and including a set of multichannel(and Ambisonics)-to-binaural conversion tools. • The performance of a perceptual evaluation stage to verify the effectiveness, realism, and quality of the techniques developed, and • The application and use of the developed tools within both scientific and artistic “case studies”. In the following chapters, sections, and subsections, the research performed between January 2006 and March 2010 will be described, outlining the different stages before, during, and after the development of the software platform, analysing the results of the perceptual evaluations and drawing conclusions that could, in the future, be considered the starting point for new and innovative research projects.

- 4 - Abstract In this research we explored role of financial variables in macro modeling and their performance in case of Mongolia. We employed two different models for assessing performance of financial variables in macro modeling, structural VAR model and small scale macro model (SSMM). In doing so, we performed different analysis such as impulse response for seeing how financial variables fit into system and forecasting performance for how accurate model performs after introducing financial variables. So our result suggested that financial variables have substantial role on macro modeling and inclusion of financial variable is performing very good result in terms of forecasting in both models. JEL Classification C01, C51, C53, E12, E52, G17 Keywords Financial markets, Small scale macro model, Structural VAR, Impulse response, Mean absolute errors. Author's e-mail batnyamd@gmail.com Supervisor's e-mail roman.horvath@gmail.com

Esta dissertaÃÃo buscou identificar atravÃs de vetores autorregressivos (VAR) a relaÃÃo entre variÃveis macroeconÃmicas e a variaÃÃo do saldo das operaÃÃes inadimplidas a mais de 60 dias. Foram construÃdos dois cenÃrios de retraÃÃo econÃmica atravÃs da tÃcnica de impulso resposta. Ademais, a pesquisa identificou que a variaÃÃo do Produto Interno Bruto (PIB) e a variaÃÃo da Taxa Selic Acumulada, em perÃodos defasados, possuem grande correlaÃÃo com a variaÃÃo do saldo das operaÃÃes inadimplidas. Os resultados apontam que i) hà uma relaÃÃo inversa entre o crescimento do saldo das operaÃÃes inadimplidas e o crescimento do PIB na Ãpoca da inadimplÃncia, ii) hà uma relaÃÃo direta entre o crescimento do saldo das operaÃÃes inadimplidas hà mais de 121 dias e o crescimento da taxa Selic um mÃs apÃs a Ãpoca da inadimplÃncia, iii) os choques negativos no PIB afetam o crescimento do saldo das operaÃÃes inadimplidas e o crescimento da PCLD por um perÃodo superior a 12 meses. / This research sought to identify through autoregressive vectors (VAR) the relationship between macroeconomic variables and the change in the balance of operations over 60 days, building two scenarios of economic downturn by impulse response technique. The research identified that the variation of the Gross Domestic Product (GDP) and the Accumulated Selic Interest Rate in delayed periods have high correlation with the change in the balance of defaulting operations. The results show that i) there is an inverse relationship between the growth of the balance of defaulting operations and GDP growth at the time of default, ii) there is a direct relationship between the growth of the balance of defaulting operations for more than 121 days and growth the Selic rate one month after the time of default, iii) negative shocks on GDP affect the growth of the balance of the defaulting operations and growth of the Allowance for more than 12 consecutive months.

AtravÃs da utilizaÃÃo de instrumentais estatÃsticos e economÃtricos para a anÃlise de sÃries temporais, buscou-se verificar as relaÃÃes entre as taxas de crescimento dos paÃses desenvolvidos e emergentes. Para tanto, utilizou-se de uma amostra contendo a taxa real de crescimento econÃmico desses paÃses no perÃodo de 1970-2007. Com base nesse estudo, verificou-se que existe causalidade, no sentido Granger, do crescimento econÃmico dos paÃses desenvolvidos em direÃÃo aos paÃses emergentes. A funÃÃo de resposta a impulsos mostrou que a resposta dos paÃses emergentes a choques no crescimento dos paÃses desenvolvidos foi a mais significativa e duradoura. / Through the use of statistical and econometric instrumentals for the analysis of time series, this work aims to verify the relationships between the economic growth rate of developed and emergent countries. For so much, it was used of a sample containing the real economic growth rate of those countries in the period of 1970-2007. With base in this study, it was verified that causality exists, in the sense of Granger, of the economic growth rate of the countries developed towards the emerging countries. The impulse response function showed that the answer of the emerging countries to impacts in the economic growth of the developed countries was the most significant and durable.

The security of wireless networks and systems is becoming increasingly important as wireless devices are more and more ubiquitous nowadays. The wireless channel exhibits the spatial uncorrelation property, which is that the characteristics of a wireless channel become uncorrelated every half carrier wavelength over distance. This property has prompted an emerging research area that utilizes wireless channel characteristics to achieve location distinction, to detect location changes or facilitate authentication of wireless users, and to establish shared secret key between legitimate communicators. This dissertation includes two work toward the security improvement of existing wireless networks and systems. With the discovered channel camouflage and manipulation techniques in wireless networks, traditional wireless channel based authentication or secure communication systems are broke or renovated. The first work proposes a new attack against all existing location distinction approaches that are built on this spatial uncorrelation property. With the discovered attack, an attacker can easily bypass authentication or camouflage location changes by creating an artificial wireless channel similar to a legitimate one. This dissertation also presents a detection technique that utilizes an auxiliary receiver or antenna to identify these fake channels. On the other hand, the second work shows that the legitimate users can also benefit from constructing these artificial wireless channels and apply them in a novel wireless key establishment. The proposed technique enables the transmitter to specify any content as the secret key and securely deliver it to the target receiver, and meanwhile removes the reconciliation process which is necessary for conventional wireless key establishment schemes.