The aim of this research is to affirm the application of closed-loop optimal control for load shifting in plants with electricity tariffs that include time-of-use (TOU) and maximum demand (MD) charges. The water pumping scheme of the Rietvlei water purification plant in the Tshwane municipality (South Africa) is selected for the case study. The objective is to define and simulate a closed-loop load shifting (scheduling) strategy for the Rietvlei plant that yields the maximum potential cost saving under both TOU and MD charges. The control problem is firstly formulated as a discrete time linear open loop optimal control model. Thereafter, the open loop optimal control model is converted into a closedloop optimal control model using a model predictive control technique. Both the open and closed-loop optimal control models are then simulated and compared with the current (simulated) level based control model. The optimal control models are solved with integer programming optimization. The open loop optimal control model is also solved with linear programming optimization and the result is used as an optimal benchmark for comparisons. Various scenarios with different simulation timeouts, switching intervals, control horizons, model uncertainty and model disturbances are simulated and compared. The effect of MD charges is also evaluated by interchangeably excluding the TOU and MD charges. The results show a saving of 5.8% to 9% for the overall plant, depending on the simulated scenarios. The portion of this saving that is due to a reduction in MD varies between 69% and 92%. The results also shows that the closed-loop optimal control model matches the saving of the open loop optimal control model, and that the closed-loop optimal control model compensates for model uncertainty and model disturbances whilst the open loop optimal control model does not. AFRIKAANS : Die doel van hierdie navorsing is om die applikasie van geslote-lus optimale beheer vir las verskuiwing in aanlegte met elektrisiteit tariewe wat tyd-van-gebruik (TVG) en maksimum aanvraag (MA) kostes insluit te bevestig. Die water pomp skema van die Rietvlei water reiniging aanleg in die Tshwane munisipaliteit (Suid-Afrika) is gekies vir die gevalle studie. Die objektief is om 'n geslote-lus las verskuiwing (skedulering) strategie vir die Rietvlei aanleg te definieer en te simuleer wat die maksimum potensiaal vir koste besparing onder beide TVG en MA kostes lewer. Die beheer probleem is eerstens gevormuleer as 'n diskreet tyd lineêre ope-lus optimale beheer model. Daarna is die ope-lus optimale beheer model aangepas na ‘n geslote-lus optimale beheer model met behulp van 'n model voorspellende beheer tegniek. Beide die ope- en geslote-lus optimale beheer modelle is dan gesimuleer en vergelyk met die huidige (gesimuleerde) vlak gebaseerde beheer model. Die optimisering van optimale beheer modelle is opgelos met geheeltallige programmering. Die optimisering van die ope-lus optimale beheer model is ook opgelos met lineêre programmering en die resultaat is gebruik as 'n optimale doelwit vir vergelykings. Verskeie scenarios met verskillende simulasie stop tye, skakel intervalle, beheer horisonne, model onsekerheid en model versteurings is gesimuleer en vergelyk. Die effek van MA kostes is ook geevalueer deur inter uitruiling van die TVG en MA kostes. Die resultate toon 'n besparing van 5. 8% tot 9% vir die algehele aanleg, afhangend van die gesimuleerde scenarios. Die deel van die besparing wat veroorsaak is deur 'n vermindering in MA wissel tussen 69% en 92%. Die resultate toon ook dat die geslote-lus optimale beheer model se besparing dieselfde is as die besparing van die ope-lus optimale beheer model, en dat die geslote-lus optimale beheer model kompenseer vir model onsekerheid en model versteurings, terwyl die ope-lus optimale beheer model nie kompenseer nie. Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Electrical, Electronic and Computer Engineering / unrestricted

Responding to the need to fill the research gap in the area of museum integrated marketing communication, the study investigated the planned, unplanned, product and service messages of selected museums in South Africa. These selected museums were the Ditsong and Iziko clusters of museums in the Gauteng Province and the Western Cape Province respectively. The clusters were selected because they are the biggest clusters of museums in the country. In an attempt to fill the research gap, the goal of the study was to develop and present an integrated marketing communication framework for the selected museums. In order to realise the goal of the study, four objectives were set. Consistent with the first objective chapter 2 analysed the South African cultural tourism sector. In this regard, the literature review revealed that South Africa’s cultural product offering is multifaceted with arts, cultural villages, literature, battlefields, museums, heritage sites nd religion comprising the main tourist attractions. Moreover, the literature review revealed that the two clusters of museums offer diversified product portfolios. The second objective was achieved in chapter 3 by analysing integrated marketing communication by means of a literature review. The literature review revealed that IMC is a logical structure of developing communication strategies. An organisation should control (planned) or influence messages (unplanned, product, service) messages to ensure message consistency and maximum communication impact. In simple terms, an organisation should strive to match its brand promise made through planned messages with actual performance as reflected in its product, service, and unplanned messages. The third objective was to analyse empirically the planned, unplanned, product and service messages of the Ditsong and Iziko clusters of museums. The results of the empirical phase of the study were presented in chapter 4. Following a mixed methods research approach, the first component of the empirical phase involved in- depth interviews with the marketing managers of the museum clusters while the second component involved a survey of visitors to the clusters. The qualitative data was analysed by establishing themes which had emerged from the interviews with the marketing managers. The quantitative data was analysed using the SPSS programme. In order to establish the relationships between the variables, a factor analysis was conducted. In addition, T-tests and ANOVAs were also conducted. The factor analysis produced three factors namely, factor 1: Above-the-line media, factor 2: Internal and external marketing and factor 3: Marketing public relations. The t-test and ANOVAs revealed that the respondents across age, province of residence, visitor retention and educational level rate service messages the most highly of all the IMC messages. On the whole, the empirical study revealed that both the participants and the respondents share the same views on what should be done in terms of the planned, unplanned, service and product messages of museums to ensure message consistency and maximum communication impact. The structural equation modelling indicated the interrelatedness of the various messages as well as their influence on one another. The fourth objective was to develop and present an integrated marketing communication framework for the Ditsong and Iziko museum clusters. This objective was realised in chapter five. The framework was informed by both the literature review and the empirical study. As regards the literature review the framework differs from some other works on IMC in that an attempt was made to align the framework to IMC message typology in its entirety. With regard to the empirical study, the IMC programme phase of the framework incorporates the recommendations of the respondents. It is hoped that the framework will empower the museums both to ensure message consistency and to maximise communication impact in spite of the divergent message needs of their multiple stakeholders. / Thesis (PhD (Tourism Management))--North-West University, Potchefstroom Campus, 2013.

Responding to the need to fill the research gap in the area of museum integrated marketing communication, the study investigated the planned, unplanned, product and service messages of selected museums in South Africa. These selected museums were the Ditsong and Iziko clusters of museums in the Gauteng Province and the Western Cape Province respectively. The clusters were selected because they are the biggest clusters of museums in the country. In an attempt to fill the research gap, the goal of the study was to develop and present an integrated marketing communication framework for the selected museums. In order to realise the goal of the study, four objectives were set. Consistent with the first objective chapter 2 analysed the South African cultural tourism sector. In this regard, the literature review revealed that South Africa’s cultural product offering is multifaceted with arts, cultural villages, literature, battlefields, museums, heritage sites nd religion comprising the main tourist attractions. Moreover, the literature review revealed that the two clusters of museums offer diversified product portfolios. The second objective was achieved in chapter 3 by analysing integrated marketing communication by means of a literature review. The literature review revealed that IMC is a logical structure of developing communication strategies. An organisation should control (planned) or influence messages (unplanned, product, service) messages to ensure message consistency and maximum communication impact. In simple terms, an organisation should strive to match its brand promise made through planned messages with actual performance as reflected in its product, service, and unplanned messages. The third objective was to analyse empirically the planned, unplanned, product and service messages of the Ditsong and Iziko clusters of museums. The results of the empirical phase of the study were presented in chapter 4. Following a mixed methods research approach, the first component of the empirical phase involved in- depth interviews with the marketing managers of the museum clusters while the second component involved a survey of visitors to the clusters. The qualitative data was analysed by establishing themes which had emerged from the interviews with the marketing managers. The quantitative data was analysed using the SPSS programme. In order to establish the relationships between the variables, a factor analysis was conducted. In addition, T-tests and ANOVAs were also conducted. The factor analysis produced three factors namely, factor 1: Above-the-line media, factor 2: Internal and external marketing and factor 3: Marketing public relations. The t-test and ANOVAs revealed that the respondents across age, province of residence, visitor retention and educational level rate service messages the most highly of all the IMC messages. On the whole, the empirical study revealed that both the participants and the respondents share the same views on what should be done in terms of the planned, unplanned, service and product messages of museums to ensure message consistency and maximum communication impact. The structural equation modelling indicated the interrelatedness of the various messages as well as their influence on one another. The fourth objective was to develop and present an integrated marketing communication framework for the Ditsong and Iziko museum clusters. This objective was realised in chapter five. The framework was informed by both the literature review and the empirical study. As regards the literature review the framework differs from some other works on IMC in that an attempt was made to align the framework to IMC message typology in its entirety. With regard to the empirical study, the IMC programme phase of the framework incorporates the recommendations of the respondents. It is hoped that the framework will empower the museums both to ensure message consistency and to maximise communication impact in spite of the divergent message needs of their multiple stakeholders. / Thesis (PhD (Tourism Management))--North-West University, Potchefstroom Campus, 2013.

<p>This thesis studies subclasses of the class of H-matrices and their applications, with<br />emphasis on the investigation of the Schur complement properties. The contributions<br />of the thesis are new nonsingularity results, bounds for the maximum norm of the<br />inverse matrix, closure properties of some matrix classes under taking Schur<br />complements, as well as results on localization and separation of the eigenvalues of<br />the Schur complement based on the entries of the original matrix.</p> / <p>Докторска дисертација изучава поткласе класе Х-матрица и њихове примене,<br />првенствено у истраживању својстава Шуровог комплемента. Оригиналан допринос<br />тезе представљају нови услови за регуларност матрица, оцене максимум норме<br />инверзне матрице, резултати о затворености појединих класа матрица на Шуров<br />комплемент, као и резултати о локализацији и сепарацији карактеристичних<br />корена Шуровог комплемента на основу елемената полазне матрице.</p> / <p>Doktorska disertacija izučava potklase klase H-matrica i njihove primene,<br />prvenstveno u istraživanju svojstava Šurovog komplementa. Originalan doprinos<br />teze predstavljaju novi uslovi za regularnost matrica, ocene maksimum norme<br />inverzne matrice, rezultati o zatvorenosti pojedinih klasa matrica na Šurov<br />komplement, kao i rezultati o lokalizaciji i separaciji karakterističnih<br />korena Šurovog komplementa na osnovu elemenata polazne matrice.</p>

The pressure on clean and sustainable energy supplies is increasing. In this regard energy conversion by electrochemical processes plays a major role, for both fuel cell reactions and electrolysis reactions. The sulphur dioxide oxidation reaction (SOR) is a common reaction found in the Hybrid Sulphur Cycle (HyS) and the HyS is a way to produce large-scale hydrogen (H2). The problem with the use of the HyS and fuel cells is the cost involved as large amounts of Pt are required for effective operation. The aim of the study was to determine whether there was an alternative catalyst which was more efficient and cost-effective than Pt. The oxygen reduction reaction (ORR), the ethanol oxidation reaction (EOR) and SOR were studied by means of different electrochemical techniques (cyclovoltammetry (CV), linear polarization (LP) and rotating disk electrode (RDE)) on polycrystalline platinum (Pt) and palladium (Pd). The SRR and EOR are common reactions occurring at the cathode and anode, respectively, in fuel cells and these reactions have been investigated extensively. The reason for studying the reactions was as a preparation for the SOR. This study compared polycrystalline Pt and Pd for the different reactions, with the main focus on the SOR as Pd is considerably cheaper than Pt, and for the SOR polycrystalline Pd has by no means been investigated intensively. Polycrystalline Pt and Pd were compared by different electrochemical techniques and analyses. The Koutecky-Levich and Levich analyses were used to (i) calculate the number of e- involved in the relevant reaction, (ii) to determine whether the reaction was mass transfer controlled at high overpotentials and (iii) whether the reaction mechanism changed with potential. Next the kinetic current density ( k) was calculated from Koutecky-Levich analyses, which was further used for Tafel slope analyses. If it was not possible to carry out the analyses, the activation energy (Ea) was used to determine the electrocatalytic activity of the catalyst. The electrocatalytic activity was also determined by comparing onset potentials (Es), peak potentials (Ep) and limited/maximum current density ( b/ p) of each catalyst. This study was only a preliminary study for the SOR and therefore, further studies are certainly required. It seemed Pd shows better electrocatalytic activity than Pt for the SRR in an alkaline electrolyte because of similar Es, but Pd produced a higher cathodic current density. Pt showed a lower Es than Pd for the SRR in an acid electrolyte, but Pd delivered a higher cathodic current density. This, therefore, means that the SRR in an acid electrolyte is kinetically more favourable on Pd than on Pt. For the EOR better electrocatalytic activity was obtained with Pd than with Pt in an alkaline electrolyte due to higher current densities at lower potentials and Pd showed lower Ea values than Pt in the potential range normally used for fuel cells. Pd was inactive for EOR in an acid electrolyte, while a reaction occurred on Pt. A possible reason for this observation may be due to the H2 absorbing strongly on Pd thus blocking the active positions on the electrode surfaces, preventing further reaction. Pd showed higher electrocatalytic activity for the SOR due to lower Es and higher current densities at low potentials. From the RDE studies it was established that the SRR in an alkaline electrolyte on polycrystalline Pt and Pd was mass transfer controlled at low potentials (high overpotentials), but the SRR in an acid electrolyte was only mass transfer controlled on Pt. The SOR was not mass transfer controlled on polycrystalline Pt and Pd at high potentials (high overpotentials). These assumptions were confirmed by Levich analysis. Using Koutecky-Levich analysis, it was determined that the reaction mechanism on polycrystalline Pt and Pd changed with potential for SRR in an alkaline electrolyte and the SOR. For the SRR in an acid electrolyte the reaction mechanism remained constant with changes in potential on polycrystalline Pd, but the reaction mechanism on polycrystalline Pt changed with potential. These assumptions were confirmed by the number of e-, calculated using Koutecky-Levich analyses. Levich and Koutecky-Levich analyses were not performed for EOR as an increase in rotation speed did not produce an increase in current density. Tafel slope analyses were conducted by making use of overpotentials and k, where possible. As in the case of ethanol, it was not possible to execute Koutecky-Levich analyses and, therefore, it was not possible to perform Tafel slope analyses using k. Tafel slope analyses for the EOR was therefore performed with normal current densities at 0 rotations per minute (rpm). The reaction mechanisms on Pt and Pd for the SRR in alkaline and acidic electrolytes differed due to different Tafel slopes. Pt and Pd displayed similar Tafel slopes for the EOR in alkaline electrolyte, thus suggesting that the reaction mechanisms on Pt and Pd were the same. For the SOR it seemed that the reaction mechanism on Pt and Pd were similar because of similar Tafel slopes. This was only a preliminary and comparative study for polycrystalline Pt and Pd, and the reaction mechanism was not further studied by means of spectroscopic techniques. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2014

The pressure on clean and sustainable energy supplies is increasing. In this regard energy conversion by electrochemical processes plays a major role, for both fuel cell reactions and electrolysis reactions. The sulphur dioxide oxidation reaction (SOR) is a common reaction found in the Hybrid Sulphur Cycle (HyS) and the HyS is a way to produce large-scale hydrogen (H2). The problem with the use of the HyS and fuel cells is the cost involved as large amounts of Pt are required for effective operation. The aim of the study was to determine whether there was an alternative catalyst which was more efficient and cost-effective than Pt. The oxygen reduction reaction (ORR), the ethanol oxidation reaction (EOR) and SOR were studied by means of different electrochemical techniques (cyclovoltammetry (CV), linear polarization (LP) and rotating disk electrode (RDE)) on polycrystalline platinum (Pt) and palladium (Pd). The SRR and EOR are common reactions occurring at the cathode and anode, respectively, in fuel cells and these reactions have been investigated extensively. The reason for studying the reactions was as a preparation for the SOR. This study compared polycrystalline Pt and Pd for the different reactions, with the main focus on the SOR as Pd is considerably cheaper than Pt, and for the SOR polycrystalline Pd has by no means been investigated intensively. Polycrystalline Pt and Pd were compared by different electrochemical techniques and analyses. The Koutecky-Levich and Levich analyses were used to (i) calculate the number of e- involved in the relevant reaction, (ii) to determine whether the reaction was mass transfer controlled at high overpotentials and (iii) whether the reaction mechanism changed with potential. Next the kinetic current density ( k) was calculated from Koutecky-Levich analyses, which was further used for Tafel slope analyses. If it was not possible to carry out the analyses, the activation energy (Ea) was used to determine the electrocatalytic activity of the catalyst. The electrocatalytic activity was also determined by comparing onset potentials (Es), peak potentials (Ep) and limited/maximum current density ( b/ p) of each catalyst. This study was only a preliminary study for the SOR and therefore, further studies are certainly required. It seemed Pd shows better electrocatalytic activity than Pt for the SRR in an alkaline electrolyte because of similar Es, but Pd produced a higher cathodic current density. Pt showed a lower Es than Pd for the SRR in an acid electrolyte, but Pd delivered a higher cathodic current density. This, therefore, means that the SRR in an acid electrolyte is kinetically more favourable on Pd than on Pt. For the EOR better electrocatalytic activity was obtained with Pd than with Pt in an alkaline electrolyte due to higher current densities at lower potentials and Pd showed lower Ea values than Pt in the potential range normally used for fuel cells. Pd was inactive for EOR in an acid electrolyte, while a reaction occurred on Pt. A possible reason for this observation may be due to the H2 absorbing strongly on Pd thus blocking the active positions on the electrode surfaces, preventing further reaction. Pd showed higher electrocatalytic activity for the SOR due to lower Es and higher current densities at low potentials. From the RDE studies it was established that the SRR in an alkaline electrolyte on polycrystalline Pt and Pd was mass transfer controlled at low potentials (high overpotentials), but the SRR in an acid electrolyte was only mass transfer controlled on Pt. The SOR was not mass transfer controlled on polycrystalline Pt and Pd at high potentials (high overpotentials). These assumptions were confirmed by Levich analysis. Using Koutecky-Levich analysis, it was determined that the reaction mechanism on polycrystalline Pt and Pd changed with potential for SRR in an alkaline electrolyte and the SOR. For the SRR in an acid electrolyte the reaction mechanism remained constant with changes in potential on polycrystalline Pd, but the reaction mechanism on polycrystalline Pt changed with potential. These assumptions were confirmed by the number of e-, calculated using Koutecky-Levich analyses. Levich and Koutecky-Levich analyses were not performed for EOR as an increase in rotation speed did not produce an increase in current density. Tafel slope analyses were conducted by making use of overpotentials and k, where possible. As in the case of ethanol, it was not possible to execute Koutecky-Levich analyses and, therefore, it was not possible to perform Tafel slope analyses using k. Tafel slope analyses for the EOR was therefore performed with normal current densities at 0 rotations per minute (rpm). The reaction mechanisms on Pt and Pd for the SRR in alkaline and acidic electrolytes differed due to different Tafel slopes. Pt and Pd displayed similar Tafel slopes for the EOR in alkaline electrolyte, thus suggesting that the reaction mechanisms on Pt and Pd were the same. For the SOR it seemed that the reaction mechanism on Pt and Pd were similar because of similar Tafel slopes. This was only a preliminary and comparative study for polycrystalline Pt and Pd, and the reaction mechanism was not further studied by means of spectroscopic techniques. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2014

This dissertation study, entitled ‘The development of a reading culture in the Foundation Phase through comprehensive parent involvement’, focused on the challenge of developing a reading culture in which a positive change takes place in the learners’ attitudes towards reading and in particular, towards reading for enjoyment, when parents are comprehensively involved in the process. The research is found to be relevant as many of the learners in the participating school showed little to no interest in reading for enjoyment and saw reading merely as a means of studying. The methodology used in the study is qualitative in nature and included a literature review, case studies and semi-structured interviews. The results of the study showed that the implementation of a comprehensive parent involvement model has a positive impact on the creation of a reading culture. The learners were more inclined to read for enjoyment when their parents participated both in reading programmes and in fun reading activities at home. The learners and parents who actively participated in this study all indicated that they had a greater appreciation of reading for enjoyment after the implementation of the programme. Based on the study findings, recommendations were made for improvements to assist in the issue of creating a reading culture in schools. / Die studie getiteld ‘Die ontwikkeling van ‘n lees-kultuur in die Grondslagfase deur omvattende ouerbetrokkenheid’, het gefokus op die uitdaging om ‘n lees-kultuur te ontwikkel waar ‘n positiewe verandering in leerders se gevoel teenoor lees plaasvind, spesifiek lees vir genot, wanneer hulle ouers intensief betrokke is in die proses. Die navorsing is relevant aangesien baie van die leerders in die betrokke skool min tot geen belangstelling getoon het teenoor lees vir genot en het lees bloot as ‘n metode van studie beleef. Die metodologie wat in die studie gebruik was was kwalitatief van aard en het ‘n literatuurstudie, gevallestudies en semi-gestruktureerde onderhoude ingesluit. Die resultate van die studie het getoon dat die implementering van ‘n omvattende ouer-betrokkenheid model ‘n positiewe impak op die ontwikkeling van ‘n lees-kultuur gehad het. Die leerders was meer geneig om vir genot te lees wanneer hulle ouers deelgeneem het aan die lees-program en aan die pret lees-aktiwiteite tuis. Die leerders en hulle ouers wat aktief deelgeneem het aan die studie, het almal aangedui dat hulle ‘n groter waardering vir lees vir genot gehad het na die implementering van die program. Voorstelle om te help met die ontwikkeling van ‘n lees-kultuur is gemaak wat gebaseer was op die bevindings van die studie. / Thuto, e nang le sehlooho se reng 'Ho nts'etsa pele setso sa ho bala ka Sekhahla sa Motheo ka ho kenyeletsa ho kopanyelletsa ha motsoali', ho lebisitse phephetso ea ho hlaolela setso sa ho bala moo phetoho e ntle e etsoang ka maikutlo a barupeluoa ho bala le ka ho khetheha, ho bala bakeng sa thabo, ha batsoali ba ikakhela ka setotsoana mosebetsing ona. Phuputso e fumanoa e le ea bohlokoa ha ba bangata ho baithuti sekolong se kenang sekolo ba sa bontše thahasello ho bala bakeng sa thabo 'me ba bona ho bala feela e le mokhoa oa ho ithuta. Mokhoa o sebelisoang thuputsong ea lipatlisiso e ne e le mokhoa oa boleng bo botle 'me o kenyelelitse tlhahlobo ea lingoliloeng, lipatlisiso tsa liketsahalo le lipuisano tse sa tšoaneng. Liphello tsa phuputso li bontšitse hore ts'ebetso ea kakaretso ea ho kenya letsoho ho motsoali e na le tšusumetso e matla ho thehoa ha setso sa ho bala. Barupeluoa ba ne ba rata ho bala bakeng sa thabo ha batsoali ba bona ba ne ba kopanela ka bobeli mananeong a ho bala le mesebetsing e monate ea ho bala lapeng. Baithuti le batsoali ba ileng ba kenya letsoho thuputsong ena bohle ba bontšitse hore ba ananela haholo ho bala bakeng sa thabo ka mor'a kopo ea ts'ebetso. Ho itšetlehile ka liphuputso tsa lithuto, liphuputso li entsoe bakeng sa ntlafatso ea ho thusa tabeng ea ho theha setso sa ho bala likolong. / Educational Foundations / M. Ed. (Socio-Education)