Tuberculosis is a disease that has a detrimental effect on the economic growth of South Africa. The country’s TB mortality rate is amongst the highest in the world, and the worst affected industry is mining. Effective environmental controls of tuberculosis in mining areas remain a challenge, mainly because there is a lack of quantitative data to guide the implementation of these controls. No occupational exposure limits exist for bio–aerosols, particularly Mycobacterium tuberculosis. This makes it difficult to distinguish between high– and low risk areas. It is believed that a single inhaled M. tuberculosis particle can cause the tuberculosis disease, and as this disease can deteriorate all major systems of the body, great care should be taken in the classification of an area. Aim: This study aimed to quantify the environmental presence of the M. tuberculosis bacilli in various occupational settings of a platinum mine. Method: The monitored areas are all structures above ground, and include high TB risk areas, such as the hospital TB Ward, and low TB risk areas, such as an office area. Personal monitoring of the staff in high TB risk areas has also been conducted. Monitoring was done via the PTFE filter sampling method and the SKC Bio–Sampler impinger method. The results of these two methods were compared to determine which method is more effective. The environmental variables, such as carbon dioxide and -monoxide levels, temperature (both ambient and wet– bulb), and relative humidity, were also monitored in order to identify any possible correlations between these variables and the levels of ambient TB particles. The effectiveness of the Ultraviolet Germicidal Irradiation (UVGI) system, which is in place in some of the monitored areas, was also indirectly assessed, i.e. to see if there are any M. tuberculosis particles present in an area that makes use of an UVGI system. The PCR analytical method was used to quantify the number of M. tuberculosis bacilli sampled, and the results were statistically analysed. Results: M. tuberculosis was found to be present in the office area, the laundry room, the hospital’s waiting area, the training facility, the dining room, and the mobile clinic. No M. tuberculosis particles were found in the hospital’s TB Ward and the change houses of the mine. The results showed that the PTFE filter method had a greater efficiency than the SKC Bio– Sampler in monitoring environmental M. tuberculosis particles, as the PTFE filter method yielded positive samples where the SKC Bio–Sampler did not. There is a practical significant difference between the two methods. No viable correlations between the environmental variables and M. tuberculosis prevalence were established due to the low number of samples taken. Conclusion: It seems that the effectiveness of a UVGI system is dependent on the number of people crowded into that specific area and the ventilation thereof. A UVGI system is only a precautionary measure and not a solution. There are too many factors that still need better understanding before the risk of contracting environmental TB in high risk areas of a mine can be determined. The high risk areas seem to be occupational settings that have poor ventilation, but accommodate a large number of people. The highest risk of TB infection remains close contact with infected individuals, as the results of the employee monitoring testified. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2011.

Tuberculosis is a disease that has a detrimental effect on the economic growth of South Africa. The country’s TB mortality rate is amongst the highest in the world, and the worst affected industry is mining. Effective environmental controls of tuberculosis in mining areas remain a challenge, mainly because there is a lack of quantitative data to guide the implementation of these controls. No occupational exposure limits exist for bio–aerosols, particularly Mycobacterium tuberculosis. This makes it difficult to distinguish between high– and low risk areas. It is believed that a single inhaled M. tuberculosis particle can cause the tuberculosis disease, and as this disease can deteriorate all major systems of the body, great care should be taken in the classification of an area. Aim: This study aimed to quantify the environmental presence of the M. tuberculosis bacilli in various occupational settings of a platinum mine. Method: The monitored areas are all structures above ground, and include high TB risk areas, such as the hospital TB Ward, and low TB risk areas, such as an office area. Personal monitoring of the staff in high TB risk areas has also been conducted. Monitoring was done via the PTFE filter sampling method and the SKC Bio–Sampler impinger method. The results of these two methods were compared to determine which method is more effective. The environmental variables, such as carbon dioxide and -monoxide levels, temperature (both ambient and wet– bulb), and relative humidity, were also monitored in order to identify any possible correlations between these variables and the levels of ambient TB particles. The effectiveness of the Ultraviolet Germicidal Irradiation (UVGI) system, which is in place in some of the monitored areas, was also indirectly assessed, i.e. to see if there are any M. tuberculosis particles present in an area that makes use of an UVGI system. The PCR analytical method was used to quantify the number of M. tuberculosis bacilli sampled, and the results were statistically analysed. Results: M. tuberculosis was found to be present in the office area, the laundry room, the hospital’s waiting area, the training facility, the dining room, and the mobile clinic. No M. tuberculosis particles were found in the hospital’s TB Ward and the change houses of the mine. The results showed that the PTFE filter method had a greater efficiency than the SKC Bio– Sampler in monitoring environmental M. tuberculosis particles, as the PTFE filter method yielded positive samples where the SKC Bio–Sampler did not. There is a practical significant difference between the two methods. No viable correlations between the environmental variables and M. tuberculosis prevalence were established due to the low number of samples taken. Conclusion: It seems that the effectiveness of a UVGI system is dependent on the number of people crowded into that specific area and the ventilation thereof. A UVGI system is only a precautionary measure and not a solution. There are too many factors that still need better understanding before the risk of contracting environmental TB in high risk areas of a mine can be determined. The high risk areas seem to be occupational settings that have poor ventilation, but accommodate a large number of people. The highest risk of TB infection remains close contact with infected individuals, as the results of the employee monitoring testified. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2011.

The purpose of this study was to investigate the effect of a new intervention method, Technology Assisted Therapy for Separation Anxiety (TTSA), on the psychosocial functioning and quality of life of persons with intellectual and visual disability who experience separation anxiety and exhibit challenging behaviour. A pre-experimental within group design was used with randomised multiple baselines and staggered intervention start points. The data was collected at an institution in the Netherlands that provides long-term care and residence for persons with intellectual disability and visual impairment. Six participants took part in this study. This research was informed by Bowlby‟s attachment theory, which conceptualises the tendency of human beings to forge strong emotional bonds with others and explains how the disturbance of this bond might lead to various forms of emotional distress and personality disturbances. The interplay of separation anxiety and challenging behaviour with respect to the formation of attachment relationships provides the specific theoretical context in which this study is grounded. The results indicate that both the separation anxiety experienced and the challenging behaviour exhibited by the participants decreased significantly after the implementation of TTSA. Their psychosocial functioning and quality of life also increased significantly. This study demonstrates the first successful application of TTSA to treat separation anxiety and challenging behaviour in persons with intellectual and visual disability. TTSA therefore has the potential to be a valid intervention to address these disorders. / MA (Research Psychology), North-West University, Potchefstroom Campus, 2015

The purpose of this study was to investigate the effect of a new intervention method, Technology Assisted Therapy for Separation Anxiety (TTSA), on the psychosocial functioning and quality of life of persons with intellectual and visual disability who experience separation anxiety and exhibit challenging behaviour. A pre-experimental within group design was used with randomised multiple baselines and staggered intervention start points. The data was collected at an institution in the Netherlands that provides long-term care and residence for persons with intellectual disability and visual impairment. Six participants took part in this study. This research was informed by Bowlby‟s attachment theory, which conceptualises the tendency of human beings to forge strong emotional bonds with others and explains how the disturbance of this bond might lead to various forms of emotional distress and personality disturbances. The interplay of separation anxiety and challenging behaviour with respect to the formation of attachment relationships provides the specific theoretical context in which this study is grounded. The results indicate that both the separation anxiety experienced and the challenging behaviour exhibited by the participants decreased significantly after the implementation of TTSA. Their psychosocial functioning and quality of life also increased significantly. This study demonstrates the first successful application of TTSA to treat separation anxiety and challenging behaviour in persons with intellectual and visual disability. TTSA therefore has the potential to be a valid intervention to address these disorders. / MA (Research Psychology), North-West University, Potchefstroom Campus, 2015

Advances in molecular immunology and rapid technical evolution during the past two decades have led to a new class of medicines called biologics. Recently, a large number of biologics, or biologic immunomodulators, directed towards an array of immune–mediated diseases, have entered the market. This has lead to a dramatic change in the immunotherapy of autoimmune diseases, as biologics present new potential to improve or substitute conventional immunosuppressive therapies. According to literature, biologics are used by only a small number of a health plan’s members, (approximately one per cent), but a single occurrence can be relatively expensive. Furthermore, there is an indication that the frequency of use and cost of biologics are on the rise, and as more biologics enter the market, health plans and employers face the challenge of controlling costs while ensuring that biologics are affordable. The general objective of this study was to determine the prevalence and cost of biologic immunomodulating medicine in the treatment of certain autoimmune diseases during the period 2005 to 2008 in a section of the private health care sector of South Africa, by employing a medicine claims database as a source to obtain necessary information. A quantitative, retrospective drug utilisation review (rDUR) was performed on computerised medication records (medicine claims data) for four consecutive years (i.e. 2005 to 2008) provided by a pharmacy benefit management company (PBM). The study population consisted of all patients on the database who received at least one medicine item with adalimumab, etanercept, infliximab, interferon beta–1a, interferon 1–b or rituximab as active ingredient and who were diagnosed with either rheumatoid arthritis (RA), multiple sclerosis (MS) or Crohn’s disease between 1 January 2005 and 31 December 2008. Between 2005 and 2008, an average of 1,305,201 patients appeared on the total database, and of these 0.055% (n = 713) received biologic immunomodulating medicine. More than two thirds of biological users were female and most patients who received these medicine items were between the ages of 39 and 64 years, followed by those patients aged between 25 and 39 years. Biologic immunomodulating medicine items (n = 11,914) and biologic prescriptions (n = 9,537) represented 0.016% of the total number of medicine items (N = 76,129,173) and 0.030% of the total number of prescriptions (N = 31,985,153). The percentage contribution of biologic immunomodulators to the total number of medicine items and prescriptions on the total database increased each year, and in four years’ time the percentage of all the medicine items on the total database that included biologic immunomodulators had tripled, from 0.009% to 0.023%. The total cost of biologic immunomodulating medicine accounted for 1.278% of the total cost (N = R7, 483,759,176.23) of all medication claimed through the PBM between 2005 and 2008. The percentage contribution of biologic immunomodulators to the total medicine expenditure also increased from one year to another for the four–year study period. The average cost of a biologic immunomodulating medicine item increased with 71.10% from 2005 (R5602.71 ± 2166.61) to (R9586.25 ± 5956.56) in 2008. The CPI for biologic immunomodulators, (CPI = 60.00 for 2005; CPI = 74.62.17 for 2006; CPI = 85.26 for 2007; and CPI = 86.96 for 2008) indicated that biologic immunomodulating medicine items were relatively expensive and the d–value between the average cost per biologic immunomodulator and the average cost per non–biological medicine item (d–value = 2.54 in 2005, d–value = 3.32 in 2006, d–value = 2.23 in 2007 and d–value = 1.59 in 2008) furthermore indicated that the impact of biological therapies was large and practically significant. Rheumatoid arthritis patients represented 19.78% of the total number of patients (n = 713) who claimed the biologic immunomodulators during the four–year period, MS patients (n = 172) represented 24.12% and Crohn’s patients (n = 11) represented 1.5%. Biological drugs prescribed to RA patients represented 0.28% (n = R20, 708,818.82) of the total cost (N = R7, 483,759,176.23) of all medication claimed through the PBM during the four–year period, while those prescribed to MS patients represented 0.41% (R30, 922,520.07) and those prescribed to Crohn’s disease patients represented 0.015% (R1, 108,568.02). Although biologic immunomodulating medicine items used in the treatment of RA, MS and Crohn’s disease are relatively expensive, it seems that the number of other medication prescribed to patients with these diseases decreased after treatment with biologics, which may influence the medicine treatment cost of these patients. It can be concluded that even though biologic immunomodulators are used by only a very small percentage of the total patient population in a section of the private health care sector of South Africa, they are relatively expensive and have a considerable impact not only the medical aid scheme, but also on the patient. / Thesis (M.Pharm (Pharmacy Practice))--North-West University, Potchefstroom Campus, 2011.

Advances in molecular immunology and rapid technical evolution during the past two decades have led to a new class of medicines called biologics. Recently, a large number of biologics, or biologic immunomodulators, directed towards an array of immune–mediated diseases, have entered the market. This has lead to a dramatic change in the immunotherapy of autoimmune diseases, as biologics present new potential to improve or substitute conventional immunosuppressive therapies. According to literature, biologics are used by only a small number of a health plan’s members, (approximately one per cent), but a single occurrence can be relatively expensive. Furthermore, there is an indication that the frequency of use and cost of biologics are on the rise, and as more biologics enter the market, health plans and employers face the challenge of controlling costs while ensuring that biologics are affordable. The general objective of this study was to determine the prevalence and cost of biologic immunomodulating medicine in the treatment of certain autoimmune diseases during the period 2005 to 2008 in a section of the private health care sector of South Africa, by employing a medicine claims database as a source to obtain necessary information. A quantitative, retrospective drug utilisation review (rDUR) was performed on computerised medication records (medicine claims data) for four consecutive years (i.e. 2005 to 2008) provided by a pharmacy benefit management company (PBM). The study population consisted of all patients on the database who received at least one medicine item with adalimumab, etanercept, infliximab, interferon beta–1a, interferon 1–b or rituximab as active ingredient and who were diagnosed with either rheumatoid arthritis (RA), multiple sclerosis (MS) or Crohn’s disease between 1 January 2005 and 31 December 2008. Between 2005 and 2008, an average of 1,305,201 patients appeared on the total database, and of these 0.055% (n = 713) received biologic immunomodulating medicine. More than two thirds of biological users were female and most patients who received these medicine items were between the ages of 39 and 64 years, followed by those patients aged between 25 and 39 years. Biologic immunomodulating medicine items (n = 11,914) and biologic prescriptions (n = 9,537) represented 0.016% of the total number of medicine items (N = 76,129,173) and 0.030% of the total number of prescriptions (N = 31,985,153). The percentage contribution of biologic immunomodulators to the total number of medicine items and prescriptions on the total database increased each year, and in four years’ time the percentage of all the medicine items on the total database that included biologic immunomodulators had tripled, from 0.009% to 0.023%. The total cost of biologic immunomodulating medicine accounted for 1.278% of the total cost (N = R7, 483,759,176.23) of all medication claimed through the PBM between 2005 and 2008. The percentage contribution of biologic immunomodulators to the total medicine expenditure also increased from one year to another for the four–year study period. The average cost of a biologic immunomodulating medicine item increased with 71.10% from 2005 (R5602.71 ± 2166.61) to (R9586.25 ± 5956.56) in 2008. The CPI for biologic immunomodulators, (CPI = 60.00 for 2005; CPI = 74.62.17 for 2006; CPI = 85.26 for 2007; and CPI = 86.96 for 2008) indicated that biologic immunomodulating medicine items were relatively expensive and the d–value between the average cost per biologic immunomodulator and the average cost per non–biological medicine item (d–value = 2.54 in 2005, d–value = 3.32 in 2006, d–value = 2.23 in 2007 and d–value = 1.59 in 2008) furthermore indicated that the impact of biological therapies was large and practically significant. Rheumatoid arthritis patients represented 19.78% of the total number of patients (n = 713) who claimed the biologic immunomodulators during the four–year period, MS patients (n = 172) represented 24.12% and Crohn’s patients (n = 11) represented 1.5%. Biological drugs prescribed to RA patients represented 0.28% (n = R20, 708,818.82) of the total cost (N = R7, 483,759,176.23) of all medication claimed through the PBM during the four–year period, while those prescribed to MS patients represented 0.41% (R30, 922,520.07) and those prescribed to Crohn’s disease patients represented 0.015% (R1, 108,568.02). Although biologic immunomodulating medicine items used in the treatment of RA, MS and Crohn’s disease are relatively expensive, it seems that the number of other medication prescribed to patients with these diseases decreased after treatment with biologics, which may influence the medicine treatment cost of these patients. It can be concluded that even though biologic immunomodulators are used by only a very small percentage of the total patient population in a section of the private health care sector of South Africa, they are relatively expensive and have a considerable impact not only the medical aid scheme, but also on the patient. / Thesis (M.Pharm (Pharmacy Practice))--North-West University, Potchefstroom Campus, 2011.

Please read the abstract in the section 00front of this document / Thesis (PhD)--University of Pretoria, 2010. / Immunology / unrestricted

Problem statement Due to HIV and AIDS impacting on communities, devastating consequences have been predicted. The number of orphans and vulnerable children (OVC) in need of care is escalating, causing social workers’ caseloads to become unmanageable. These OVC who lost their parents through death are suffering multiple losses due to being orphaned. The material, protection and affection needs have to be addressed in a holistic, eco-systematic, multidisciplinary team approach. In practice social workers tend to focus mainly on the material and protection needs of OVC due to high caseloads and staff turnover, neglecting their affection needs. Social workers need to work with foster parents and children in identifying potential risk factors that could lead to risk behaviour in foster children who have lost their parents through death. The researcher designed an assessment tool that could enable social workers in practice to do an effective risk assessment of OVC in foster care. Intervention could be planned accordingly by setting goals to address risk factors timeously in an attempt to prevent future problem behaviour in OVC placed in foster care. Aim To develop an assessment tool for social workers to identify risk behaviour in foster children who have experienced multiple losses such as the loss of one or both parents. Method A mixed methods design was used, specifically the sequential and explanatory design which involved collecting and analysing both qualitative and quantitative data. These obtained data were then connected and integrated. Results It was proved that a Risk assessment tool helped social workers to identify risk factors in a team effort between social workers, foster parents and children. Meeting the psychosocial needs of OVC placed in foster care more effectively is important in order to prevent the development of negative behaviour. / PhD (Social Work), North-West University, Potchefstroom Campus, 2015

Problem statement Due to HIV and AIDS impacting on communities, devastating consequences have been predicted. The number of orphans and vulnerable children (OVC) in need of care is escalating, causing social workers’ caseloads to become unmanageable. These OVC who lost their parents through death are suffering multiple losses due to being orphaned. The material, protection and affection needs have to be addressed in a holistic, eco-systematic, multidisciplinary team approach. In practice social workers tend to focus mainly on the material and protection needs of OVC due to high caseloads and staff turnover, neglecting their affection needs. Social workers need to work with foster parents and children in identifying potential risk factors that could lead to risk behaviour in foster children who have lost their parents through death. The researcher designed an assessment tool that could enable social workers in practice to do an effective risk assessment of OVC in foster care. Intervention could be planned accordingly by setting goals to address risk factors timeously in an attempt to prevent future problem behaviour in OVC placed in foster care. Aim To develop an assessment tool for social workers to identify risk behaviour in foster children who have experienced multiple losses such as the loss of one or both parents. Method A mixed methods design was used, specifically the sequential and explanatory design which involved collecting and analysing both qualitative and quantitative data. These obtained data were then connected and integrated. Results It was proved that a Risk assessment tool helped social workers to identify risk factors in a team effort between social workers, foster parents and children. Meeting the psychosocial needs of OVC placed in foster care more effectively is important in order to prevent the development of negative behaviour. / PhD (Social Work), North-West University, Potchefstroom Campus, 2015

In this dissertation an in-depth study was conducted into the design, implementation and evaluation of a QPSK-based receiver structure for application in a UMTS WCDMA environment. The novelty of this work lies with the specific receiver architecture aimed to optimise the BER performance when possibly sparse data streams are transmitted. This scenario is a real possibility according to Verd´u et al [1] and Hagenauer et al [2–6]. A novel receiver structure was conceptualised, developed and evaluated in both narrowband and wideband scenarios, where it was found to outperform conventional receivers when a sparse data stream is transmitted. In order to reach the main conclusions of this study, it was necessary to develop a realistic simulation platform. The developed platform is capable of simulating a communication system meeting the physical layer requirements of the UMTS WCDMA standard. The platform can also perform narrowband simulations. A flexible channel emulator was developed that may be configured to simulate AWGN channel conditions, frequency non-selective fading (either Rayleigh or Rician with a configurable LOS component and Doppler spread), or a full multipath scenario where each path has a configurable LOS component, Doppler spread, path gain and path delay. It is therefore possible to even simulate a complex, yet realistic, COST207-TU channel model. The platform is also capable of simulating MUI. Each interfering user has a unique and independent multipath fading channel, while sharing the same bandwidth. Finally, the entire platform executes all simulations in baseband for improved simulation times. The research outputs of this work are summarised below: <ul> <li>A parameter, the sparseness measure, was defined in order to quantify the level by which a data stream differs from an equiprobable data stream.</li> <li>A novel source model was proposed and developed to simulate data streams with a specified amount of sparseness.</li> <li>An introductory investigation was undertaken to determine the effect of simple FEC techniques on the sparseness of an encoded data stream.</li> <li>Novel receiver structures for both narrowband and wideband systems were proposed, developed and evaluated for systems where possibly sparse data streams may be transmitted.</li> <li>Analytic expressions were derived to take the effect of sparseness into account in communication systems, including expressions for the joint PDF of a BPSK branch, the optimal decision region of a detector in AWGN conditions as well as the BER performance of a communication system employing the proposed optimal receiver in both AWGN channel conditions as well as in flat fading channel conditions.</li> <li>Numerous BER performance curves were obtained comparing the proposed receiver structure with conventional receivers in a variety of channel conditions, including AWGN, frequency non-selective fading and a multipath COST207-TU channel environment, as well as the effect of MUI</li></ul>. AFRIKAANS : In hierdie verhandeling word ’n in-diepte studie gedoen rakende die ontwerp, implementasie en evaluasie van ’n KPSK-gebaseerde ontvanger struktuur wat in ’n UMTS WKVVT omgewing gebruik kan word. Die bydrae van hierdie werk lˆe in die spesifieke ontvanger argitektuur wat daarop mik om die BFT werksverrigting te optimeer wanneer yl data strome versend word. Hierdie is ’n realistiese moontlikheid volgens Verd´u et al [1] en Hagenauer et al [2–6]. ’n Nuwe ontvanger struktuur is gekonsepsualiseer, ontwikkel en evalueer vir beide noueband en wyeband stelsels, waar dit gevind is dat dit beter werksverrigting lewer as tradisionele ontvangers wanneer yl data strome versend word. Dit was nodig om ’n realistiese simulasie platform te ontwikkel om die belangrikste gevolgtrekkings van hierdie studie te kan maak. Die ontwikkelde platform is in staat om ’n kommunikasie stelsel te simuleer wat aan die fisiese laag vereistes van die UMTS WKVVT standaard voldoen. Die platform kan ook noueband stelsels simuleer. ’n Aanpasbare kanaal simulator is ontwikkel wat opgestel kan word om SWGR kanaal toestande, plat duining (beide Rayleigh of Ricies met ’n verstelbare siglyn komponent en Doppler verspreiding), sowel as ’n veelvuldige pad omgewing (waar elke unieke pad ’n verstelbare siglyn komponent, Doppler verspreiding, pad wins en pad vertraging het) te emuleer. Dit is selfs moontlik om ’n komplekse, maar steeds realistiese COST207-TU kanaal model te simuleer. Die platform het ook die vermo¨e om VGS te simuleer. Elke steurende gebruiker het ’n unieke en onafhanklike veelvuldige pad deinende kanaal, terwyl dieselfde bandwydte gedeel word. Laastens, alle simulasies van die platvorm word in basisband uitgevoer wat verkorte simulasie periodes verseker. Die navorsingsuitsette van hierdie werk kan as volg opgesom word: <ul> <li>’n Parameter, die ylheidsmaatstaf, is gedefin¨ýeer om dit moontlik te maak om die vlak waarmee die ylheid van ’n datastroom verskil van ’n ewekansige stroom te versyfer.</li> <li>’n Nuwe bronmodel is voorgestel en ontwikkel om datastrome met ’n spesifieke ylheid te emuleer.</li> <li>’n Inleidende ondersoek is onderneem om vas te stel wat die effek van VFK tegnieke op die ylheid van ’n enkodeerde datastroom is.</li> <li>Nuwe ontvanger strukture is voorgestel, ontwikkel en evalueer vir beide noueband en wyeband stelsels waar yl datastrome moontlik versend kan word.</li> <li>Analitiese uitdrukkings is afgelei om die effek van ylheid in ag te neem in kommunikasie stelsels. Uitdrukkings vir onder andere die gedeelte WDF van ’n BFVK tak, die optimale beslissingspunt van ’n detektor in SWGR toestande, sowel as die BFT werksverrigting van ’n kommunikasie stelsel wat van die voorgestelde optimale ontvangers gebruik maak, hetsy in SWGR of in plat duinende kanaal toestande.</li> <li>Talryke BFT werksverrigting krommes is verkry wat die voorgestelde ontvanger struktuur vergelyk met die konvensionele ontvangers in ’n verskeidenheid kanaal toestande, insluitend SWGR, plat duinende kanale en ’n veelvuldige pad COST207-TU kanaal omgewing, sowel as in die teenwoordigheid van VGS.</li></ul></p Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Electrical, Electronic and Computer Engineering / unrestricted