This dissertation presents a pumping system operation efficiency improvement solution that includes optimal selection and control of the water pump. This solution is formulated based on the performance, operation, equipment and technology (POET) framework. The focus is on the minimization of the operational energy cost. This efficiency improvement solution is divided into three stages in accordance with the operation category of the POET framework. The first stage is to select the optimal pump capacity by considering both energy efficiency and load shifting requirements. The second stage is to develop a flexible pump controlling strategy that combines and balances the contributions from energy efficiency and load shifting. The last stage is to improve the robustness of the control system using the closed-loop model predictive control approach. An optimal pump capacity selection model is formulated. In this model, additional capacity requirements for load shifting are considered along with the traditional energy efficiency requirements. By balancing the contributions from load shifting and energy efficiency, the operational energy cost can be reduced by up to 37%. An optimal pump control is formulated. The objective of this control model is to balance the energy efficiency and load shifting contributions during the operation and minimize the operational energy cost. This control model is tested under different operational conditions and it is compared to other existing control strategies. The simulation and comparison results show that the proposed control strategy achieves the lowest operational energy cost in comparison to other strategies. This optimal pump control model is further modified into the closed-loop model predictive control format to increase the robustness of the control system under operation uncertainties. A mixed integer particle swarm optimization algorithms is employed to solve the optimization problems in this research. AFRIKAANS : Hierdie verhandeling bied ’n verbeterde oplossing vir die operasionele doeltreffendheid van pompstelsels wat die optimale keuse en beheer van die waterpomp insluit. Hierdie oplossing is geformuleer op ’n raamwerk wat werkverrigting, bedryf, toerusting en tegnologie in ag neem. Die oplossing fokus op die vermindering van bedryfsenergie koste. Hierdie oplossing is onderverdeel in drie fases soos bepaal deur die bedryfskategorie gegrond op die bogenoemde raamwerk: Die eerste fase is die keuse van die optimale pompkapasiteit deur beide energiedoeltreffendheid en lasverskuiwing in ag te neem. Die tweede fase is om ’n buigbare pompbeheer strategie te ontwikkel wat ’n goeie balans handhaaf tussen die onderskeie bydraes van energiedoeltreffendheid en lasverskuiwing. Die derde fase is om die stabiliteit van die beheerstelsel te verbeter deur gebruik te maak van ’n geslote-lus beheermodel met voorspellende beheer (Predictive Control). ’n Model vir die keuse van optimale pompkapasiteit is geformuleer. In hierdie model word vereistes vir addisionele pompkapasiteit vir lasverskuiwing sowel as vereistes in terme tradisionele energiedoeltreffendheid in ag geneem. Deur die regte verhouding tussen die onderskeie bydraes van energiedoeltreffendheid en lasverskuiwing te vind kan ’n besparing van tot 37% op die energiekoste verkry word. Optimale pompbeheer is geformuleer. Die doel van die beheermodel is om die bydraes van energiedoeltreffendheid en lasverskuiwing te balanseer en om die bedryfsenergie koste te minimiseer. Hierdie beheermodel is getoets onder verskillende bedryfstoestande en dit is vergelyk met ander bestaande beheerstrategiee. Die simulasie en vergelyking van resultate toon dat die voorgestelde beheerstrategie die laagste bedryfsenergie koste behaal in vergelyking met ander strategiee. Hierdie optimale pomp beheermodel is verder aangepas in ’n geslote beheermodel met voorspellende beheerformaat om die stabiliteit van die beheerstelsel te verbeter onder onsekere bedryfstoestande. ’n Gemende heelgetal partikel swerm optimisasie (Mixed interger particle swarm optimization) algoritme is gebruik om die optimiseringsprobleme op te los tydens hierdie navorsingsoefening. / Dissertation (MEng)--University of Pretoria, 2011. / Electrical, Electronic and Computer Engineering / Unrestricted

THIS THESIS IS IN THE EXAMINATION PROCESS The ability to locate symbols on a visual display forms an integral part of the effective use of AAC systems. Characteristics of display design and perceptual features of symbols have been shown to influence rate and accuracy of symbol location (Thistle&Wilkinson, 2009; Wilkinson, Carlin,&Jagaroo, 2006). The current study endeavoured to compare the use of two colour-coded organisational strategies (alphabetical order and subcategorisation) for their effectiveness in symbol location and to investigate if some bottom-up features influenced the performance of the participants in these tasks. 114 learners in Grade 1 to 3 in a mainstream school were randomly divided into two groups. Both of the groups were exposed to two visual search tests in alternating order. The tests involved searching for 36 visual targets amongst 81 coloured Picture Communication Symbols on a computer screen in one of two colour-coded organizational methods, namely alphabetical order or subcategorisation. The data from the research task was collected through computer logging of all mouse selections. Findings showed that locating symbols on a computer screen with a subcategorisation strategy was significantly faster and more accurate than with an alphabetical strategy for the Grade 1 to 3 participants. The differences between the rates and accuracy of target symbol location using the two strategies decreased significantly as grade increased. It was also found that although the tests in this study placed heavy top-down processing demands on the participants, there was still evidence of bottom-up factors influencing their performance. Implications for display design in AAC clinical practice were discussed. / Thesis (PhD)--University of Pretoria, 2012. / Centre for Augmentative and Alternative Communication (CAAC) / Unrestricted

In the light of the facts given in literature it is evident that players in the game of netball need to meet specific anthropometric (body length, body mass, percentage body fat and percentage muscle mass), physical (pliancy, abdominal power, aerobic endurance and anaerobic endurance) and motor (speed over 5 m and 10 m, agility and explosive power) requirements. This consequently necessitates specific attention to be given to the mentioned requirements. In spite of the fact that a few studies do exist that enter into the requirements of the profile of netball players in different positions, as well as into what the effect of a periodization programme is on anthropometric, physical and motor requirements, voids do exist regarding the positional profile of 15 to 17 year old netball players and as to what the effect is of a sport specific periodization programme in the course of a season on 15 to 17 year old netball players. In the light of the above–mentioned, this study was undertaken with the aim to: 1) Determine the requirements for 15 to 17 year old netball players; 2) Compile positional profile scales of netball specific requirement for 15 to 17 year old players in the Tlokwe region; 3) Establish the effect of a sport specific periodization programme on anthropometric, physical and motor requirements for 15 to 17 year old female netball players, of a specific school in the Tlokwe region, in the course of a season. 96 players (28 goalkeepers, 44 centre court players and 24 defenders) between ages 15 and 17 years from two high schools in the North–West Province were used in the study to determine positional differences. A group of only 22 player of one school was exposed to a sport specific periodization programme for purposes of the study, since the coach and players from only one school’s teams were prepared to participate in the sport scientific intervention programme for the full duration of the netball season. The afore–mentioned group was evaluated over a period of two years, namely prior to the start of the season (T1), after conclusion of the season once the sport specific periodization programme was completed (T2), prior to the start of the season in the subsequent year (T3) and after conclusion of the season without the sport specific being followed. The data is processed on the basis of descriptive statistics. Furthermore, the practical significance of test result changes between the respective groups and different test sessions were compared using Cohen’s effect size. Literature was consulted to determine whether specific requirements exist for netball players and whether differences occur in the three positional groups. However, no literature could be traced in which only netball specific requirements for 15 to 17 year old players were focused on. The literature did indeed point out clear anthropometric differences between the three positional groups, namely attacking, centre court and defence players in club and elite netball players. The goalkeeper and defence players are, according to literature, considerably taller and heavier than the centre court players. Literature also indicated that differences do indeed occur regarding physical and motor requirements. Centre court players are significantly faster and more agile than the goalkeeper and defenders. However, there were components of which the differences were not prominent concerning the three positional groups. Where a specific positional profile of anthropometric, physical and motor requirements for 15 to 17 year old female netball players was composed from available data of players in the North–West Province, Tlokwe region, the results of the anthropometric requirements indicated that body length showed a large significant difference between the three positional groups, with defenders being the tallest, followed by goalkeepers, and the centre court players being the shortest. Body mass also showed a medium significant difference between goalkeepers and centre court players as well as between centre court players and defence players. Goalkeepers were heavier than centre court players, and defenders also showed a higher body mass than centre court players. The other two variables, namely percentage fat and percentage muscle mass, only showed small practically significant differences, in this group of netball players, between the test sessions. With the physical and motor requirements, results indicated that large practically significant differences occurred in vertical jumping, 5 m speed, 10 m speed and agility between the groups. The general trend observed in the profiles was that the largest significant differences occurred between goalkeepers and defence players on the one hand and centre court players on the other. Vertical jump and speed showed a large significant difference between goalkeepers and centre court players as well as between centre court players and defenders, although the goalkeepers and defenders’ results corresponded considerably. Other large significant differences occurred in the 10 m speed as well as in 505–agility to the left between centre court players and defenders. In summary it can be mentioned that the most and the largest significant differences occurred between goalkeepers and centre court players as well as between defenders and centre court players. Only one medium significant difference occurred between the goalkeepers and defenders, which is ankle dorsiflexion and which can be ascribed to injuries. From this it can be inferred that a positional profile can indeed be compiled for the different positional groups in netball, but that the requirements of positional variables between goalkeepers and defenders correspond largely and that the large difference between the last–mentioned two groups occur when compared with those of the centre court players of this specific group. The results of the group of twenty–two players that were evaluated twice during the course of both netball seasons indicate that the variable that showed a large significant difference between T1 and T2, following the sport specific periodization program, was body mass (inverted difference). Although there was no large significant difference, it can clearly be deduced from the graphs presented in the study that a visible difference (improvement) was observed in most of the variables. The variables that showed a large practically significant difference with the training of the coach’s general programme, were ankle dorsiflexion on the left, abdominal power and 5 m speed (inverted effect). A number of variables indeed existed that also showed medium and small significant differences during the course of both seasons, but it will not be mentioned here. A number of shortcomings and recommendations did indeed come to the fore during and after the course of the study. It should, however, be borne in mind that such a structured periodization programme is very important for the development of netball potential. / Thesis (Ph.D. (Human Movement Science))--North-West University, Potchefstroom Campus, 2011.

In the light of the facts given in literature it is evident that players in the game of netball need to meet specific anthropometric (body length, body mass, percentage body fat and percentage muscle mass), physical (pliancy, abdominal power, aerobic endurance and anaerobic endurance) and motor (speed over 5 m and 10 m, agility and explosive power) requirements. This consequently necessitates specific attention to be given to the mentioned requirements. In spite of the fact that a few studies do exist that enter into the requirements of the profile of netball players in different positions, as well as into what the effect of a periodization programme is on anthropometric, physical and motor requirements, voids do exist regarding the positional profile of 15 to 17 year old netball players and as to what the effect is of a sport specific periodization programme in the course of a season on 15 to 17 year old netball players. In the light of the above–mentioned, this study was undertaken with the aim to: 1) Determine the requirements for 15 to 17 year old netball players; 2) Compile positional profile scales of netball specific requirement for 15 to 17 year old players in the Tlokwe region; 3) Establish the effect of a sport specific periodization programme on anthropometric, physical and motor requirements for 15 to 17 year old female netball players, of a specific school in the Tlokwe region, in the course of a season. 96 players (28 goalkeepers, 44 centre court players and 24 defenders) between ages 15 and 17 years from two high schools in the North–West Province were used in the study to determine positional differences. A group of only 22 player of one school was exposed to a sport specific periodization programme for purposes of the study, since the coach and players from only one school’s teams were prepared to participate in the sport scientific intervention programme for the full duration of the netball season. The afore–mentioned group was evaluated over a period of two years, namely prior to the start of the season (T1), after conclusion of the season once the sport specific periodization programme was completed (T2), prior to the start of the season in the subsequent year (T3) and after conclusion of the season without the sport specific being followed. The data is processed on the basis of descriptive statistics. Furthermore, the practical significance of test result changes between the respective groups and different test sessions were compared using Cohen’s effect size. Literature was consulted to determine whether specific requirements exist for netball players and whether differences occur in the three positional groups. However, no literature could be traced in which only netball specific requirements for 15 to 17 year old players were focused on. The literature did indeed point out clear anthropometric differences between the three positional groups, namely attacking, centre court and defence players in club and elite netball players. The goalkeeper and defence players are, according to literature, considerably taller and heavier than the centre court players. Literature also indicated that differences do indeed occur regarding physical and motor requirements. Centre court players are significantly faster and more agile than the goalkeeper and defenders. However, there were components of which the differences were not prominent concerning the three positional groups. Where a specific positional profile of anthropometric, physical and motor requirements for 15 to 17 year old female netball players was composed from available data of players in the North–West Province, Tlokwe region, the results of the anthropometric requirements indicated that body length showed a large significant difference between the three positional groups, with defenders being the tallest, followed by goalkeepers, and the centre court players being the shortest. Body mass also showed a medium significant difference between goalkeepers and centre court players as well as between centre court players and defence players. Goalkeepers were heavier than centre court players, and defenders also showed a higher body mass than centre court players. The other two variables, namely percentage fat and percentage muscle mass, only showed small practically significant differences, in this group of netball players, between the test sessions. With the physical and motor requirements, results indicated that large practically significant differences occurred in vertical jumping, 5 m speed, 10 m speed and agility between the groups. The general trend observed in the profiles was that the largest significant differences occurred between goalkeepers and defence players on the one hand and centre court players on the other. Vertical jump and speed showed a large significant difference between goalkeepers and centre court players as well as between centre court players and defenders, although the goalkeepers and defenders’ results corresponded considerably. Other large significant differences occurred in the 10 m speed as well as in 505–agility to the left between centre court players and defenders. In summary it can be mentioned that the most and the largest significant differences occurred between goalkeepers and centre court players as well as between defenders and centre court players. Only one medium significant difference occurred between the goalkeepers and defenders, which is ankle dorsiflexion and which can be ascribed to injuries. From this it can be inferred that a positional profile can indeed be compiled for the different positional groups in netball, but that the requirements of positional variables between goalkeepers and defenders correspond largely and that the large difference between the last–mentioned two groups occur when compared with those of the centre court players of this specific group. The results of the group of twenty–two players that were evaluated twice during the course of both netball seasons indicate that the variable that showed a large significant difference between T1 and T2, following the sport specific periodization program, was body mass (inverted difference). Although there was no large significant difference, it can clearly be deduced from the graphs presented in the study that a visible difference (improvement) was observed in most of the variables. The variables that showed a large practically significant difference with the training of the coach’s general programme, were ankle dorsiflexion on the left, abdominal power and 5 m speed (inverted effect). A number of variables indeed existed that also showed medium and small significant differences during the course of both seasons, but it will not be mentioned here. A number of shortcomings and recommendations did indeed come to the fore during and after the course of the study. It should, however, be borne in mind that such a structured periodization programme is very important for the development of netball potential. / Thesis (Ph.D. (Human Movement Science))--North-West University, Potchefstroom Campus, 2011.