The predominant nuclear fuel used globally at present is uranium which is a finite resource. Thorium has been identified as an alternative nuclear fuel source that can be utilized in almost all existing uranium–based reactors and can significantly help in conserving limited uranium reserves. Furthermore, the elimination of proliferation risks associated with thorium–based fuel cycles is a key reason for re–evaluating the possible utilization of thorium in high temperature reactors. In addition to the many advantages that thorium–based fuel has over uranium–based fuel, there are vast thorium resources in the earth's crust that up until the present have not been exploited optimally. This study focuses on determining the amount of uranium ore that can be saved using thorium as a nuclear fuel in HTR's. Four identical 200 MWth high temperature reactors are considered which make use of different fuel cycles. These fuel cycles range from the conventional uranium fuel cycle to a thorium–based fuel cycle in which no U–238 is present and have been simulated using the VSOP–A system of computer codes. This study also considers the effect that protactinium, an isotope that occurs in thorium–based fuel cycles, will have on the decay heat production in the case of a depressurized loss of coolant (DLOFC) accident. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2011.

Literature indicates that events like a wine festival have many role players involved that need each other for them to be successful. The more role players there are, the more complex the event becomes, as in the case of the Wacky Wine Festival which is spread over 48 wine farms. The most important role players are the visitors and wine farmers that represent the demand and supply side of the festival. Local enterprises, wine farmers and the festival organisers put a lot of effort into the event, such as their time, money and skills. It is essential for these role players to know that they will get a return on their investment and for the host community to know that the festival will make a contribution to their local economy. Furthermore, literature indicates that the festival can improve the economic position of the role players by targeting the high spending market through intensive marketing that focuses on this particular segment. Therefore, the purpose of this study was to determine the contribution of the Wacky Wine Festival to the local economy and to compile a profile of the heavy spender. To achieve the latter, a quantitative study was carried out by means of two surveys via questionnaires that were handed out to both the visitor and wine farmer. The data was then captured in Microsoft© Excel©. In Article 1 (Chapter 2) the sales multiplier effect and an analytical framework were used to determine the contribution of the festival to the host community. In Article 2 (Chapter 3) different tests and analyses were used to compile a profile of the heavy spender such as the K–means clustering, Chi–Squared, the Mann–Whitney non–parametric test and an ANOVA analysis. The results from Article 1 (Chapter 2) showed that the Wacky Wine Festival had an positive economic contribution of an estimated R29.9 million to the host community`s economy. From a demand and supply point of view, the visitors contributed R15.4 million and the wine farmers R6 million. From the results, it could be derived that the festival had low leakages in comparison with other festivals. iii The results from Article 2 (Chapter 3) indicated that the heavy and low spenders differ in terms of gender, language, age, occupation, number of people paying for in travelling group, residence and number of days spent at the festival. It was clear from the results that if the festival organisers and wine farmers focus marketing strategies on the high spending segment, this can lead to a R10 million increase in the Wacky Wine Festival’s revenue, thus improving the economic contribution of the event to the local economy of Robertson. / Thesis (M.Com. (Tourism))--North-West University, Potchefstroom Campus, 2012.

The predominant nuclear fuel used globally at present is uranium which is a finite resource. Thorium has been identified as an alternative nuclear fuel source that can be utilized in almost all existing uranium–based reactors and can significantly help in conserving limited uranium reserves. Furthermore, the elimination of proliferation risks associated with thorium–based fuel cycles is a key reason for re–evaluating the possible utilization of thorium in high temperature reactors. In addition to the many advantages that thorium–based fuel has over uranium–based fuel, there are vast thorium resources in the earth's crust that up until the present have not been exploited optimally. This study focuses on determining the amount of uranium ore that can be saved using thorium as a nuclear fuel in HTR's. Four identical 200 MWth high temperature reactors are considered which make use of different fuel cycles. These fuel cycles range from the conventional uranium fuel cycle to a thorium–based fuel cycle in which no U–238 is present and have been simulated using the VSOP–A system of computer codes. This study also considers the effect that protactinium, an isotope that occurs in thorium–based fuel cycles, will have on the decay heat production in the case of a depressurized loss of coolant (DLOFC) accident. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2011.

Literature indicates that events like a wine festival have many role players involved that need each other for them to be successful. The more role players there are, the more complex the event becomes, as in the case of the Wacky Wine Festival which is spread over 48 wine farms. The most important role players are the visitors and wine farmers that represent the demand and supply side of the festival. Local enterprises, wine farmers and the festival organisers put a lot of effort into the event, such as their time, money and skills. It is essential for these role players to know that they will get a return on their investment and for the host community to know that the festival will make a contribution to their local economy. Furthermore, literature indicates that the festival can improve the economic position of the role players by targeting the high spending market through intensive marketing that focuses on this particular segment. Therefore, the purpose of this study was to determine the contribution of the Wacky Wine Festival to the local economy and to compile a profile of the heavy spender. To achieve the latter, a quantitative study was carried out by means of two surveys via questionnaires that were handed out to both the visitor and wine farmer. The data was then captured in Microsoft© Excel©. In Article 1 (Chapter 2) the sales multiplier effect and an analytical framework were used to determine the contribution of the festival to the host community. In Article 2 (Chapter 3) different tests and analyses were used to compile a profile of the heavy spender such as the K–means clustering, Chi–Squared, the Mann–Whitney non–parametric test and an ANOVA analysis. The results from Article 1 (Chapter 2) showed that the Wacky Wine Festival had an positive economic contribution of an estimated R29.9 million to the host community`s economy. From a demand and supply point of view, the visitors contributed R15.4 million and the wine farmers R6 million. From the results, it could be derived that the festival had low leakages in comparison with other festivals. iii The results from Article 2 (Chapter 3) indicated that the heavy and low spenders differ in terms of gender, language, age, occupation, number of people paying for in travelling group, residence and number of days spent at the festival. It was clear from the results that if the festival organisers and wine farmers focus marketing strategies on the high spending segment, this can lead to a R10 million increase in the Wacky Wine Festival’s revenue, thus improving the economic contribution of the event to the local economy of Robertson. / Thesis (M.Com. (Tourism))--North-West University, Potchefstroom Campus, 2012.

Sunflower (Helianthus annuus L.) high oleic acid content lines differ from conventional sunflower by an increase in oleic acid (C18:1) content of more than 60%. The current sunflower cultivars under production in South Africa are standard sunflower with high levels of linoleic acid (C18:2). The aim of this study was to improve the quality of oil produced by local sunflower germplasm with respect to oleic acid through employing a marker-assisted breeding technique to facilitate and speed up the recovery of the high oleic acid allele into the background of the recurrent parent genome. Eleven sunflower breeding genotypes with high and low oleic acid traits were obtained from the Agricultural Research Council-Grain Crops Institute (ARC-GCI) in Potchefstroom. The breeding genotypes were phenotypically characterised based on their oleic and linoleic acid levels using gas chromatography. Results demonstrated that the average mean of oleic and linoleic acid contents in high oleic acid genotypes were 72% and 17% respectively, while the average mean of oleic acid and linoleic acid contents in wild type lines were 33.5 % and 54 % respectively. These results indicated a perfect negative correlation between the amount of oleic and linoleic acids possessed in high and low oleic acid genotypes (R2 = -99.16%). Sequence characterised amplified region (SCAR) markers were tested to ascertain if any of the ten available dominant FAD2-1 markers was segregating with the high oleic acid allele. Four dominant SCAR markers (FAD2-1F4/R1; FAD2-1F4/R2; FAD2-1F13/R1; FAD2-1F14/R2) were strongly associated with the high oleic acid trait (P< 0.001). With regard to the inheritance of the high oleic acid trait, 143 plants of the F2 segregating population derived from a cross between the high oleic acid parent (AP901-95-3-4-1) and low oleic acid parent (H55-9-2-1-1) were genotyped with the four SCAR markers to determine the genetic state concerning the high oleic acid gene (Ol). Results from a Chi square analysis of the observed frequencies of each dominant FAD2-1 marker locus in 143 F2 individuals indicated that the deviation from the expected ratio of 3:1 (high to low oleic acid) was not statistically significant (P< 0.95) from the observed segregation ratio. These results were consistent with the previous finding that an incomplete dominant gene governs sunflower high oleic acid. A multiplex assay of 78 Simple sequence repeat (SSR) markers was optimised and evaluated on 143 plants of the F2 population to determine suitable SSR markers that can be used in a marker-assisted background selection. Only 14 markers were suitable for marker-assisted background selection based on their high polymorphic information content, allele frequency and maximum allele numbers. In conclusion, this study demonstrated the potential of using SSR and SCAR marker systems as a breeding tool to characterise and speed up the selection process in marker-assisted backcross breeding. / Thesis (MSc (Botany))--North-West University, Potchefstroom Campus, 2013.

Sunflower (Helianthus annuus L.) high oleic acid content lines differ from conventional sunflower by an increase in oleic acid (C18:1) content of more than 60%. The current sunflower cultivars under production in South Africa are standard sunflower with high levels of linoleic acid (C18:2). The aim of this study was to improve the quality of oil produced by local sunflower germplasm with respect to oleic acid through employing a marker-assisted breeding technique to facilitate and speed up the recovery of the high oleic acid allele into the background of the recurrent parent genome. Eleven sunflower breeding genotypes with high and low oleic acid traits were obtained from the Agricultural Research Council-Grain Crops Institute (ARC-GCI) in Potchefstroom. The breeding genotypes were phenotypically characterised based on their oleic and linoleic acid levels using gas chromatography. Results demonstrated that the average mean of oleic and linoleic acid contents in high oleic acid genotypes were 72% and 17% respectively, while the average mean of oleic acid and linoleic acid contents in wild type lines were 33.5 % and 54 % respectively. These results indicated a perfect negative correlation between the amount of oleic and linoleic acids possessed in high and low oleic acid genotypes (R2 = -99.16%). Sequence characterised amplified region (SCAR) markers were tested to ascertain if any of the ten available dominant FAD2-1 markers was segregating with the high oleic acid allele. Four dominant SCAR markers (FAD2-1F4/R1; FAD2-1F4/R2; FAD2-1F13/R1; FAD2-1F14/R2) were strongly associated with the high oleic acid trait (P< 0.001). With regard to the inheritance of the high oleic acid trait, 143 plants of the F2 segregating population derived from a cross between the high oleic acid parent (AP901-95-3-4-1) and low oleic acid parent (H55-9-2-1-1) were genotyped with the four SCAR markers to determine the genetic state concerning the high oleic acid gene (Ol). Results from a Chi square analysis of the observed frequencies of each dominant FAD2-1 marker locus in 143 F2 individuals indicated that the deviation from the expected ratio of 3:1 (high to low oleic acid) was not statistically significant (P< 0.95) from the observed segregation ratio. These results were consistent with the previous finding that an incomplete dominant gene governs sunflower high oleic acid. A multiplex assay of 78 Simple sequence repeat (SSR) markers was optimised and evaluated on 143 plants of the F2 population to determine suitable SSR markers that can be used in a marker-assisted background selection. Only 14 markers were suitable for marker-assisted background selection based on their high polymorphic information content, allele frequency and maximum allele numbers. In conclusion, this study demonstrated the potential of using SSR and SCAR marker systems as a breeding tool to characterise and speed up the selection process in marker-assisted backcross breeding. / Thesis (MSc (Botany))--North-West University, Potchefstroom Campus, 2013.

Afrikaans Deneys Reitz, die derde van president F.W. Reitz se vyf oorlewende seuns, is op 2 April 1882 te midde van die politieke en ekonomiese ontwaking van die Vrystaat in Bloemfontein gebore. Hy het op die ouderdom van 17 by die Boeremagte aangesluit en doen hier die ondervindinge op wat hy later in sy eerste boek, Commando: A Boer journal of the Boer war, weergee. Met die sluit van vrede weier hy om die eed van getrouheid teenoor Brittanje af te lê en wend hom na Madagaskar waar hy onder meer as ‘n transportryer werk. Hy keer in 1903, op aandrang van Isie Smuts, na Suid-Afrika terug, kwalifiseer as ‘n prokureur en open ‘n prokureurspraktyk in die Noordoos-Vrystaatse dorp Heilbron. Gedurende die 1914-rebellie skaar hy homself aan die Botha-Smuts regering se kant en voer hy die Heilbronkommando aan teen die rebelle. Tydens die Eerste Wêreldoorlog sluit hy hom aanvanklik by Botha en Smuts in Duits-Suidwes-Afrika aan en daarna by die Britse leër in Brittanje. Hy spandeer die meeste van die Eerste Wêreldoorlog in die loopgrawe aan die Wesfront in Frankryk en vorder tot die rang van kolonel in bevel van ‘n bataljon van die First Royal Scots Fusiliers. Met sy terugkeer na Suid-Afrika in 1920 wend hy hom tot die politiek en as lid van die Suid-Afrikaanse Party verteenwoordig hy eers Bloemfontein-Suid (1920) en later Port Elizabeth. Vanaf 1929 verteenwoordig hy Barberton. Hy dien aanvanklik in die parlement as Minister van Lande, waar hy onder meer betrokke raak by wetgewing i.v.m. die totstandkoming van die Krugerwildtuin. Hy dien ook as Minister van Lande in die koalisie kabinet van J.B.M. Hertzog (1933) en daarna as Minister van Landbou en Bosbou (1935), Minister van Mynwese (1938), Minister van Naturellesake (1939) en as adjunkpremier in Smuts se Oorlogskabinet (1939-1943). Vir die periode van 1924 tot 1933 dien hy as deel van die amptelike opposisie, terwyl hy hoofsaaklik as ‘n prokureur in Johannesburg werk. In dié periode het hy ook uitgebreide private- en sakereise na onder meer Noord- en Suid-Rhodesië, die Belgiese Kongo en die Kaokoveld in Suidwes-Afrika onderneem. Sy bekendheid het hy grootliks verwerf uit die publikasie van sy herinneringe van die Anglo Boereoorlog, gepubliseer as Commando in 1929. Dit is erken as ‘n boek van uitstaande gehalte en word beskou as ‘n klassieke werk oor die Anglo-Boereoorlog. Die res van sy lewe, vanaf 1902 tot 1940, het hy in die boeke Trekking on en No outspan beskryf. Deneys Reitz was getroud met Leila Agnes Buissine Reitz (13/12/1887 – 29/12/1959). Sy was Suid-Afrika se eerste vroulike parlementslid en het Parktown verteenwoordig. Leila was veral by maatskaplike werk betrokke en het spesifiek op kinders en kindermisdadigers gefokus. Deneys en Leila het twee seuns gehad - Jan en Michael. Weens swak gesondheid word Reitz in 1943 as Hoë Kommissaris in Londen aangestel, waar hy in 1944 sterf. English Deneys Reitz, the third of president F.W. Reitz’s five living sons, was born in Bloemfontein on 2 April 1882 during the political and economical awakening of the Orange Free State. As a boy of seventeen he joined the Boer forces in the Anglo-Boer War, gaining the experience he set down in his first book, Commando: A Boer journal of the Boer war. After the peace he was an irreconcilable and lived as a transport rider in Madagascar, returning to South Africa in 1903 after prompting by Isie Smuts. He qualified as an attorney and practiced in the town of Heilbron in the north-east Free State. During the 1914 rebellion he commanded the Heilbron Commando against the rebels in support of the Botha-Smuts government. During World War I he first joined Botha and Smuts in German South West Africa and then in German East Africa, where after he enlisted with the British Army. He spent most of the First World War in the trenches in France, where he rose to command a battalion of the First Royal Scots Fusiliers. Upon his return to South Africa he entered Parliament in 1920 as a member of the South African Party, representing first Bloemfontein South (1920) and later Port Elizabeth. He represented Barberton from 1929. He initially held the portfolios of Lands (1923-24), becoming involved in developing legislation for the establishment of the Kruger National Park. He also served as Minister of Lands in the coalition government of J.B.M. Hertzog (1933), Minister of Agriculture and Forestry (1935), Minister of Mines (1938), Minister of Native Affairs (1939) and as deputy premier in Smuts’ War Cabinet (1939-1943). Reitz was a member of the formal opposition from 1924 to 1933, while also working as an attorney in Johannesburg. In this period he travelled extensively in both his private and official capacities to North and South Rhodesia, the Belgian Congo and the Kaokoveld in South West Africa. His real claim to fame, however, arises from his memoirs of the Anglo-Boer War, which he published under the title of Commando in 1929. This was immediately recognised as a work of outstanding quality and has become a South African classic on the Anglo Boer War. Later he wrote Trekking on and No outspan, continuing the story of his career. Deneys Reitz was married to Leila Agnes Buissine Reitz (13/12/1887 – 29/12/1959), the first South African women elected to parliament. She was member for Parktown. Leila, who was involved in welfare work, focused on children and delinquents. Deneys and Leila had two sons of their own - Jan en Michael. Due to ill health Reitz was appointed Union High Commissioner in London in 1943, where he later passed away. / Thesis (DPhil)--University of Pretoria, 2009. / Historical and Heritage Studies / unrestricted

In the latter part of the 20th century chronic diseases, especially cardio vascular-related diseases (CVDs) and Type 2 diabetes mellitus (DM) seemed to have emerged as substantial problems. This can be seen in the prevalence and the cost of CVDs in South Africa and worldwide. It was predicted that by the year 2030 more people would be dying from CVDs than from Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/Aids). The reasons for the occurrence of CVDs are linked to biological (i.e. hypertension, hyperlipidemia, obesity, insulin resistance, etc), psychological (i.e. emotional stress), and behavioural or lifestyle risk factors. It is known that physical exercise can aid in the treatment of CVDs. Institutions such as the American College of Sports Medicine (ACSM) recommended an exercise frequency of three times per week for 20 minutes. According to literature, a third of patients in exercise studies do not comply with their exercise protocol, and after three to six months, 50 percent will drop out of organised training groups. Less than a third of South Africans complied with exercising 30 minutes a day on most days of the week. Thus, there has been much interest among health-care providers to manage exercise compliance. Exercise compliance is a complex construct, and thus in the present study the role that behavioural patterns play was also investigated via psychological behavioural models. The major objectives of the study were the following: <ul> <li> Firstly, to determine if exercise compliance or non-compliance had an influence on shifts measured in the clinical parameters (i.e. blood pressure, blood lipid levels, blood glucose levels, body mass index, body fat percentage and cardiac risk percentage) over time.</li> <li> Secondly, to determine whether there were any correlation between the psychological behavioural models and the exercise compliance of the members over the course of the Best Med/Access Health-Disease Management Programme (BM/AH-DM Programme).</li></ul> In the present study, a retrospective data analysis was done on data collected from Best Med Medical Aid members (n = 400) who participated in a chronic disease management programme for three and a half years. The inclusion criteria for participation on the programme were the presence of one or more of the following CVDs namely: hypercholesterolemia, hypertension and DM. The members’ clinical parameters (height, body weight, body fat percentage, blood pressure, finger-prick non-fasting (random) blood cholesterol level, finger-prick non-fasting (random) blood glucose, sub-maximal V02 fitness test) were measured every three months. After a baseline assessment was done, an exercise programme was given to each member and a norm of exercising twice a week was prescribed. If members adhered to the norm they were considered compliant and if they did not adhere to the norm, they were considered as being non-compliant. Their exercise compliance, and relevant clinical parameters were measured over 30 months, although data analysis was only a reflection of the first 12 months’ data. At the beginning of the BM/AH-DM Programme the members’ Level of Readiness (LOR) to make a lifestyle change was measured via a questionnaire and by the end of the programme they completed an Implicit Theory Scale (ITS) questionnaire. Descriptive statistics (means, standard deviation) were used to determine the entire groups’ compliance, and to divide the group into compliant and noncompliant groups. The T-test or the Mann-Whitney Test (an equivalent nonparametric technique) was applied to determine significant differences between groups. Thus did the clinical parameters measured over time (baseline to 3 months, baseline to 6 months and baseline to 12 months), change more in the compliant than in the non-compliant group? And were there correlations between psychological questionnaires answers and the two exercise groups? The results indicated that the group’s exercise compliance trend decreased drastically over time. Statistical significant decreases were demonstrated in systolic (p = 0.007) and diastolic (p = 0.012) blood pressure, BMI (p = 0.072 and p = 0.0003), cardiac risk percentage (p = 0.003), and body weight (p = 0.003 and p = 0.0000). All of these decreases were seen in the exercise compliant group. There were no statistical correlations between the psychological questionnaires and the exercise groups. Limitations were the quality of the clinical data, the exercise compliance data that deteriorated over time, and the LOR and ITS questionnaires was neither valid nor reliable tools in making predictions regarding exercise behaviour/compliance. For future research it is recommended that measurements of blood pressure and cholesterol be done more thoroughly, and dietary fat intake must be monitored. A valid and reliable cardiac risk tool, LOR and ITS questionnaires must be designed. AFRIKAANS : Die voorkoms en kosteïmplikasies van kroniese siektetoestande in Suid–Afrika en wêreldwyd, het in die laaste gedeelte van die 20ste eeu ‘n wesenlike probleem geword. Kardiovaskulêre (KVS) siektes en tipe 2 diabetes mellitus (DM) is veral voorbeelde van sulke siektetoestande. Daar is voorspel dat in die jaar 2030, meer mense wêreldwyd aan KVS sal doodgaan, as aan Menslike Immuniteitsgebrekvirus/Verworwe Immuniteitsgebreksindroom (MIV/Vigs). Die risikofaktore wat met die oorsake van KVS geassosieer word, is die volgende: <ul> <li> Biologiese (met inbegrip van hipertensie, insulienweerstandigheid, hoë bloedcholesteroltellings, ens)</li> <li> Sielkundige (bv emosionele spanning) • Risikofaktore wat verband hou met lewenstyl.</li></ul> Literatuur bevestig dat fisiese oefening help om KVS en diabetes mellitus te behandel. Die American College of Sports Medicine (ACSM) het ‘n oefenriglyn van drie maal per week vir 20 minute lank as ‘n minimumfrekwensie daargestel. Volgens literatuur oefen ‘n derde van pasiënte wat deelneem aan oefeningnavorsingsstudies nie volgens die riglyne wat gestel word nie en binne die eerste drie tot ses maande sal 50% van die pasiënte ophou oefen. Navorsing wat op die Suid-Afrikaanse bevolking gedoen is, toon dat minder as ‘n derde 30 minute lank op meeste dae van die week oefen. Dus is die belangstelling van gesondheidsterapeute rakende die bestuur van gereelde oefeningdeelname geprikkel. Gereelde oefeningdeelname sluit ook die rol van gedragspatrone in en dus is sielkundige gedragsmodelle gebruik om dit ook in die huidige studie te ondersoek. Copyright / Dissertation (MA)--University of Pretoria, 2009 / Biokinetics, Sport and Leisure Sciences / unrestricted

Text in English with summaries and keywords in English, Afrikaans and Zulu / Bibliography: leaves 294-314 / How does an organisation turn good results into great results? What makes one organisation good and another great? What defines high performance organisations? Which aspects within an organisation play vital roles into taking an organisation from good to great? Are some aspects more important than others, if so, which ones? These questions have been explored and researched over the years and various researchers have proposed different theories and models that impact high performance as well as definitions around high performance with mixed results. The general aim of this research was to develop and validate a High Performance Model for an IT organisation. The concept of high performance was explored in terms of how to define high performance, which high performance models and frameworks have been developed within the literature and what sustains high performance. These existing High Performance Organisation (HPO) models and frameworks were evaluated against an identified set of criteria to arrive at a definitive theoretical model of high performance. The theoretical HPO model was developed based on the evaluation of the literature reviews together with the existing HPO model of the participating IT organisation. The main purpose of the empirical research was to gather data by means of three questionnaires, over six years, which were used to statistically determine the organisational and behavioural constructs that influence High Performance in an IT organisation in South Africa. Furthermore, the researcher developed an empirical model to verify the theoretical model. A quantitative empirical research paradigm using the survey method was followed and explanatory and descriptive research was used in this study. An HPO questionnaire was developed and administered to employees. Over the six years and three questionnaire administrations, 3,451 employees participated. A new best fitting HPO model was postulated based on new constructs postulated in the factor analysis. The model indicated that Leadership, Knowledge Management – team, Strategic Focus as well as Job Satisfaction especially contributed to high performance within the participating organisation, as well as that strong relationships exist between the HPO factors. This research should contribute towards longitudinal studies on high performance as well as a comprehensive understanding of the factors that influence high performance, within South Africa but also globally. The new HPO model should assist organisations and practitioners in measuring high performance in any organisation after validation. With increased competition and globalisation organisations struggle to survive, this study can provide a roadmap for organisations to obtain and sustain high performance. / Hoe kan ‘n organisasie goeie resultate in uitnemende resultate verander? Wat maak een organisasie goed en ‘n ander een uitnemend? Hoe word hoë prestasie organisasies gedefinieer? Watter aspekte binne ‘n organisasie speel die belangrikste rol om die organisasie van goed na uitnemend te neem? Is sommige aspekte belangriker as ander, indien wel, watter? Hierdie vrae is al deur die jare heen ondersoek en nagevors. Verskeie navorsers het verskillende definisies, teorieë en modelle wat hoe prestasie beïnvloed word ontwikkel, met gemengde resultate. Die algemene doel van hierdie navorsing was om ‘n Hoë Prestasie (HP) Model vir ‘n IT organisasie te ontwikkel en te bekragtig. Die konsep van hoë prestasie word ondersoek, meer spesifiek, die definisie van hoë prestasie, watter hoë prestasie modelle en raamwerke al ontwikkel is in die literatuur en wat hou hoë prestasie in stand. Die bestaande HP modelle en raamwerke word ge-evalueer teen kriteria wat vooraf geïdentifiseer is om sodoende ‘n beslissende teoretiese model vir hoë prestasie te onwikkel. Die teoretiese HP model was ontwikkel op grond van literatuur evaluasies, tesame met die bestaande HP model van die deelnemende IT organisasie. Die hoofdoel van die empiriese navorsing was om data te versamel deur middel van drie vraelyste, oor ‘n tydperk van ses jaar, wat gebruik is om te bepaal watter organisasie- en gedragsveranderlikes beïnvloed hoë prestasie in die deelnemende Suid-Afrikaanse IT organisasie. Die navorser het ook ‘n empiriese model ontwikkel om die teoretiese model te verifieer. ‘n Kwantitatiewe empiriese navorsingsparadigma, insluitend die vraelysmetode, was gevolg in hierdie navorsingstudie, sowel as verklarende en bevestigende navorsing. ‘n HP vraelys was ontwikkel en geadministreer. Gedurende die ses jaar en drie vraelys administrasies, het 3,451 werknemers deelgeneem. ‘n Nuwe en beter-passende HP model word gepostuleer, gebaseer op nuwe konstrukte gepostuleer in die faktoranalise. Die model wys dat Leierskap, Kennisbestuur—span, Strategiese Fokus, asook Werksbevrediging—veral bydra tot hoë prestasie in die deelnemende organisasie en dat sterk verhoudings bestaan tussen dié HP faktore. Die navorsing behoort by te dra tot longutidinale studies van hoë prestasie, asook ‘n omvattende begrip van die faktore wat hoë prestasie beïnvloed, op globale vlak, maar ook binne die Suid-Afrikaanse konteks. Die nuwe HP model behoort organisasies en praktisyns te help om hoë prestasie te meet in enige IT organisasie, nadat bekragtiging gedoen is. Met toenemende kompetisie en globalisering, sukkel organisasies om kop bo water te hou, dus kan hierdie studie ‘n padkaart bied na die verkryging en handhawing van hoë prestasie. / Ngabe inhlangano ikwenza kanjani ukwenza ukusuka kwimiphumela emihle ibe nemiphumela yezinga eliphezulu kakhulu? Ngabe yini okwenza ukuthi inhlangano ethile ibe yinhle kanti enye ibe sezingeni eliphezulu kakhulu? Ngabe yini okuchaza inhlangano esebenza ngezinga eliphezulu kakhulu? Ngabe yiziphi izinto kwinhlangano ezidlala indima ebalulekile ekwenzeni ukuthi inhlangano isuke ezingeni elihle iye kweliphezulu kakhulu? Ngabe kukhona izinto ezibalulekile ukudlula ezinye, uma zikhona, ngabe yiziphi? Le mibuzo iye yacutshungulwa nokucwaningwa eminyakeni eminingi kanti abacwaningi abehlukene baphakamise amathiyori ehlukene kanye namamodeli athinta umphumela wezinga eliphezulu kanye nezincazelo ngokusebenza kwezinga eliphezulu, ngemiphumela ehlukene. Inhloso enabile yalolu cwaningo bekuwukwenza kanye nokuqinisekisa imodeli ye-high performance model (HPO) ngokwenhlangano ye-Information Technology (IT). Kuye kwahlolisiswa umbono wokusebenza ngezinga eliphezulu ngokulandela indlela yokuchaza ukusebenza ngezinga eliphezulu, nokuthi ngabe yiwaphi amamodeli okusebenza ngezinga eliphezulu nezinhlaka ezenziwe ngaphansi kwemibhalo, kanye nokuthi yini ukuqikelela ukuqhubeka kokusebenza ngezinga eliphezulu. Amamodeli akhona e-HPO kanye nezinhlaka zahlolwa ngaphansi kwama-criteria aboniwe akhona ukuze kufinyelelwe kwithiyori echazayo ngemodeli yokusebenza ngezinga eliphezulu. Ithiyori yemodeli ye-HPO yenziwe ngokulandela uhlolo lwemibhalo ebuyekeziwe kanye nokulandela imodeli ye-HPO ekhona kwinhlangano ye-IT ebingenele ucwaningo. Inhloso enkulu yocwaningo olunobufakazi bekuwukuqoqa idata ngokwenza uhla lwemibuzo emithathu, esikhathini seminyaka eyisithupha, kanti yasetshenziswa ukunquma ngezinto ezihlukene eziphathelene nenhlangano kanye nokuziphatha kwayo okunomthelela ekusebenzeni ngezinga eliphezulu kwinhlangano ye-IT eNingizimu Afrika. Kanti futhi, umcwaningi wenze imodeli yobufakazi ukuqinisekisa imodeli yethiyori. Kulandelwe ipharadayimi yocwaningo lwamanani ngokusebenzisa inqubo ye-survey kanye nocwaningo lwencazelo nengcaciso okusetshenziswe kulolu cwaningo. Kwenziwe uhla lwemibuzo yeHPO yasetshenziswa kubasebenzi. Eminyakeni eyisithupha kusetshenziwswe uhla oluthathu lwemibuzo, kubasebenzi ababambe iqhaza abangu 3, 451. Imodeli engcono kakhulu ye-HPO iye yasetshenziswa ngokulandela uhlelo olusha olwenziwe kwinqubo yohlaziyo. Imodeli ibonise ukuthi Ubuholi, kanye Nokuphathwa koLwazi – ithimba, Ukugxilisa kwinhloso ethile kanye Nokuneliseka Ngomsebenzi ikakhulukazi yikho okunomthelela ekusebenzeni ngezinga eliphezulu enhlanganweni ebamba iqhaza. Imiphumela ibonise nobudlelwane obukhulu obuqinile obukhona phakathi kwezinto eziphathelene ne-HPO, ikakhulukazi phakathi Kwenhlangano Yokuphathwa Kolwazi, okuhambelane kakhulu ngokuqinile nezinto ezinhlano kweziyisishagalolunye eziphathelene ne-HPO. Ucwaningo lungathela esivivaneni ekuqondisiseni okujulile kwizinto ezinomthelela ekusebenzeni ngezinga eliphezulu, kuwo wonke umhlaba kanye neNingizimu Afrika ngokwayo. Imodeli entsha ye-HPO ingasiza inhlangano kanye nabasebenzi ekukaleni ukusebenza ngezinga eliphezulu kunoma yiyiphi inhlangano ye-IT, ngemuva kokuqinisekiswa. Ngokukhula kokuqhudelana kanye ne-globalisation, izinhlangano zikuthola kunzima ukuqhubekela phambili, lolu cwaningo lungahlinzeka ngomhlahlandlela kwizinhlangano ukuthola indlela yokusebenza ngezinga eliphezulu nokugcina lezo zindlela zokusebenza ngezinga eliphezulu. / Industrial and Organisational Psychology / D. Phil. (Industrial and Organisational Psychology)

The recent growth in the ambit of modern wireless communication and in particular WLAN (Wireless Local Area Network) systems has created a niche for novel designs that have the capacity to send and/or receive arbitrary orthogonal polarizations. The designs should also be able to support dual-band functionality, while maintaining a compact structure. The first aim of this dissertation was thus to develop a dual-band single radiating element that can cover the 2.4 GHz (2.4 – 2.484 GHz) band and the 5.2 GHz (5.15 – 5.85 GHz) band for the IEEE 802.11b and IEEE 802.11a WLAN standards respectively. Dual-frequency elements such as stacked-, notched- and dichroic patches have been considered, but due to the size and the high cross-polarization levels associated with these designs, the design process was propelled towards various dipole and monopole configurations. The attributes of various designs were compared, where the double Rhombus antenna pregnant with dual-band and dual-polarization potential was used as basis in the development of the DBDP (Dual-Band Dual-Polarized) antenna design. The single-element design exhibited wide bandwidths, good end-fire radiation patterns and relatively high gain over the 2.4/5.2 GHz bands. A two-element configuration was also designed and tested, to firstly increase the gain of the configuration and secondly to facilitate the transformation of the dipole design into a dual-polarized configuration. The second aim of this dissertation was to develop a dual-polarized array, while making use of only two ports, each pertaining to a specific polarization and to implement the design on a single-dielectric-layer substrate. Most dual-polarized structures such as circular, square and annular microstrip antenna designs only support one band, where multi-dielectric-layer structures are the norm. The disadvantages associated with multi-layered designs, such as fabrication difficulties, high costs, high back lobes and the size of the arrays, further supported the notion of developing an alternative configuration. The second contribution was thus the orthogonal interleaving of the two-element array configurations, to address the paucity of single-dielectric-layer dual-band dual-polarized designs that can be implemented with only two ports. This design was first developed and simulated with the aid of the commercial software package CST Microwave Studio® and the results were later corroborated with the measured data obtained from the Compact Antenna Range at the University of Pretoria. AFRIKAANS : Die onlangse groei in die area van moderne draadlose kommunikasie en met spesifieke verwysing na DLAN (Draadlose Lokale Area Netwerk) stelsels, het ‘n nis vir nuwe ontwerpe geskep. Daar word van hierdie nuwe ontwerpe die kapasiteit verlang om verskeie ortogonale polarisasies te stuur en/of te ontvang in samewerking met dubbel-band eienskappe, terwyl ‘n kompakte struktuur nogsteeds aandag moet geniet. Die eerste doel met hierdie verhandeling was dus die ontwikkeling van ‘n dubbel-band enkel stralingselement wat instaat is om die 2.4 GHz (2.4 – 2.484 GHz) band en die 5.2 GHz (5.15 – 5.85 GHz) band wat as die IEEE 802.11b en die IEEE 802.11a DLAN standaarde respektiewelik bekend staan, te bedek. Dubbel-frekwensie elemente soos onder andere die gepakte-, merkkepie- en dichromatiese strook antenne was as moontlike oplossings ondersoek, maar die grootte en hoë kruispolarisasie wat gewoonlik met hierdie ontwerpe gepaard gaan, het die ontwerpsproses in die rigting van verskeie dipool en monopool konfigurasies gestoot. Die aantreklike eienskappe van die verskeie ontwerpe was met mekaar vergelyk, waar die dubbel Rhombus antenna, verwagtend met dubbel-band dubbel-polarisasie potensiaal, as basis vir die ontwikkeling van die DBDP (Dubbel-Band Dubbel-Polarisasie) antenna ontwerp gebruik is. Die enkelelementontwerp het wye bandwydtes, goeie direktiewe stralingspatrone en relatiewe hoë wins oor die 2.4/5.2 GHz bande geopenbaar. Die twee-element konfigurasies was ook ontwerp en getoets om eerstens die wins van die konfigurasie te verhoog en tweedens om die transformasie na ‘n dubbel-gepolariseerde konfigurasie te fassiliteer. Die tweede doel van hierdie verhandeling was om ‘n dubbel-gepolariseerde elementopstelling met net twee poorte te ontwikkel, waar elkeen verantwoordelik is vir ‘n spesifieke polarisasie, en te implementeer op ‘n enkel-diëlektriese-laag substraat. Die meeste dubble-polarisasiestrukture, soos onder andere die sirkulêre-, vierkantige- en ringvormige antenne ontwerpe, kan net een frekwensieband onderhou en word gewoonlik met behulp van meervoudige-diëlektriese-laagstrukture geimplementeer. Die negatiewe eienskappe soos onder andere die vervaardigingsmoeilikhede, hoë kostes, hoë teruglobbe en die grootte van die meervoudige-elementopstellings wat aan hierdie meervoudige-diëlektriese-laagontwerpe behoort, het verder die denkbeeld van ‘n alternatiewe konfigurasie bekragtig. Die tweede hoofbydrae was dus die ortogonale insleuteling van die twee-element meervoudige-elementopstelling konfigurasies om die geringheid van enkel-diëlektriese-laag dubbel-band dubbel-polarisasie ontwerpe, wat net met twee poorte geïmplementeer kan word, te adresseer. Hierdie ontwerp was eers met behulp van die kommersiële sagtewarepakket CST Microwave Studio® ontwikkel en gesimuleer, waarna die resultate bevestig was deur meetings by die Kompakte Antenna Meetbaan van die Universiteit van Pretoria. / Dissertation (MEng)--University of Pretoria, 2011. / Electrical, Electronic and Computer Engineering / unrestricted