Energy services companies (ESCOs) typically implement energy management systems (EMSs) as part of Demand-Side Management (DSM) projects on South African mines. After DSM project completion, the mine becomes responsible for maintaining the performance of the EMS. Due to a lack of experience in using specialised EMSs, mines typically contract ESCOs for EMS maintenance. However, maintaining a large number of EMSs remotely is a resource-intensive task because of time wasted on daily monitoring and travelling to perform on-site maintenance. For the same reason, remote maintenance technologies have become widely used to maintain cellular devices, vehicles and industrial equipment. Mine EMSs typically control production-critical systems that in turn ensure safe working conditions underground. EMSs execute highly specialised control philosophies to achieve electrical energy management, while ensuring safe and productive system operation. None of the work done on remote maintenance, however, provides an integrated solution to maintain the performance of a growing number of these specialised EMSs. As part of this study, a supervisory system was developed to optimise remote maintenance of different EMS technologies. The supervisory system builds on the fundamentals of existing remote maintenance technologies, complemented by comprehensive diagnostics of specialised EMS technologies. This is possible through automated diagnostics of EMS components, the control philosophy and overall EMS performance. Maintenance management forms part of the supervisory system to ensure that maintenance is performed with optimal efficiency. A system implementation was executed to prove the feasibility of the supervisory system. The functional operation of the system was verified with pre-set scenarios that simulated day-to-day operation and common fault diagnostic events. As part of the case studies conducted for this thesis, the supervisory system was integrated with three distinct EMS technologies implemented on South African mines. To support the results of these case studies, the system validation was extended through integrations with seven additional EMSs. For the first time, a supervisory assessed the condition of the EMS components, the control philosophy and DSM performance comprehensively. The results (obtained over a period of more than six months) indicated that the average operational availability of EMS components improved from 90% to 97%. The average EMS performance improved from 1.8 MW to 2.5 MW, an improvement of 39%. The resulting electricity cost reduction achieved on the case studies accumulated to approximately R6 million during the respective assessment periods. The supervisory system facilitated efficient EMS maintenance, thus reducing the risk of unsafe working conditions and production interruptions. The system also allowed maintenance personnel to improve the diagnostic process continually, thus aligning with the standards documented in ISO 50001:2011 (ISO, 2011) regarding continual improvement of electrical energy management initiatives. The new supervisory system is scalable, thus an ESCO can maintain the performance of a growing number of EMSs remotely. Results of this study support further supervisory system integration with compatible EMS technologies, and expansion to new EMS technologies. The modular design of the supervisory system provides a basis for the development of a cross-industry platform for maintaining EMS performance. / PhD (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2014

Water Treatment Plants (WTPs) supply potable water which is transferred by pumps to various end users. WTPs and other sub-systems are energy intensive with pump installed capacities varying between 75 kW – 6 000 kW. It has therefore become important to optimise the utilisation of WTPs. Cost savings can be achieved and the load on the national grid can be reduced. The aim of this study is to develop and implement load management strategies on a municipal WTP. In this investigation the high lift pumps are deemed to be the largest consumers of electricity. Strategies to safely implement load management on a WTP were researched. By optimising the operations of the pumps, significant cost savings can be achieved. Comparisons between different electricity tariff structures were done. It was found plausible to save R 990 000 annually, on a pumping station with four 1 000 kW pumps installed, when switching to a time-of-use dependent tariff structure. Strategies to optimise plant utilisation while attempting a load management study include the optimisation of filter washing methods and raw water operations. An increase of 34% in efficiency for a filter backwash cycle was achieved. To accommodate the effects of the load management on the WTP, the operation of valves that allow water to distribute within the plant was also optimised. The implemented control strategies aimed to accomplish the full utilisation of the WTP and sub-systems to achieve savings. An average evening peak period load shift impact of 2.21 MW was achieved. Due to filter modifications the plant is able to supply 5% more water daily. A conclusion is drawn regarding the success of the strategies implemented. Recommendations are made for further research. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

Syftet med den här studien är att undersöka om de kommunikativa svårigheter som kännetecknar barn med autismspektrumtillstånd (AST) leder till svårigheter i den nu rådande kommunikationsinriktade matematikundervisningen. Efter att den senaste skollagen trädde i kraft har inte barn med AST längre samma rättighet som tidigare att gå i grundsärskolan (såvida de inte också har en utvecklingsstörning) utan i inkluderas i grundskolan.  Samtidigt som denna skollag började gälla fick grundskolan en ny läroplan med en ny kursplan i matematik. Denna kursplan lägger stort fokus på kommunikation. Detta kan bli problematiskt för elever med AST på grund av de kommunikationssvårigheter som ingår i diagnosen. I den här studien intervjuades fem lärare med erfarenhet av matematikundervisning av elever med AST i årskurs 4-6. I resultatet framkommer att samtliga lärare uppger att de elever med funktionsnedsättningen som de har erfarenhet av att undervisa uppvisar eller har uppvisat svårigheter med den kommunikativa förmågan i matematikundervisningen. Tre av de intervjuade lärarna uppgav även att de anser sig ha otillräckliga kunskaper om AST för att kunna tillgodose behoven hos eleverna med diagnosen i matematikundervisningen.

Growing demand for electricity forces suppliers to expand their generation capacity. Financing these expansion programmes results in electricity cost increases above inflation rates. By reducing electricity consumption, additional supply capacity is created at lower costs than the building of conventional power stations. Therefore, there is strong justification to reduce electricity consumption on the supplier and consumer side. The mining and industrial sectors of South Africa consumed approximately 43% of the total electricity supplied by Eskom during 2012. Approximately 10% of this electricity was used to produce compressed air. By reducing the electricity consumption of compressed air systems, operating costs are reduced. In turn this reduces the strain on the South African electricity network. Previous energy saving projects on mine compressed air systems realised savings that were not always sustainable. Savings deteriorated due to, amongst others, rapid employee turnover, improper training, lack of maintenance and system changes. There is therefore a need to improve projects that have already been implemented on mine compressed air systems. The continuous improvement of equipment (such as improved control valves) and the availability of newer technologies can be used to improve existing energy saving strategies. This study provides a solution to reduce the electricity consumption and operating costs of a deep level mine compressed air system. This was achieved by modernising and improving an existing underground compressed air saving strategy. This improvement resulted in a power saving of 1.15 MW; a saving equivalent to an annual cost saving of R4.16 million. It was found that the improved underground compressed air DSM project realised significant additional electrical energy savings. This resulted in ample cost savings to justify the implementation of the project improvements. It is recommended that opportunities to improve existing electrical energy saving projects on surface compressed air systems are investigated. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

The South African Electricity Supply Industry is one of the backbone industries in South Africa. During 2003, it became clear that the demand for electricity in South Africa was increasing at a rate that had not been predicted nor recognised before. This was a clear indication that Eskom, the national electricity supply utility, would have to invest in additional generating capacity before 2007. Eskom envisioned these problems and introduced a DSM programme, which is aimed at reducing the national peak power demand. In so doing, the immediate need for additional power generating capacity will be postponed. A major part of this program is the concept of electrical load shifting. In 2000 mining in South Africa consumed 29% of the total quantity of electricity generated, of which the gold-mining industry consumed more than half. Electricity is the exclusive power source for the application of vital health and safety-related requirements in gold mines. In some cases, these consume in excess of 55% of the total electricity used on a mine. Water-pumping systems are a major part of these important applications. This dissertation presents a study of certain aspects of real-time energy management on old gold mines, by focusing on electrical load shifting on underground water pumping systems. Old gold mines use old, proven and energy-intensive methods that were not designed to conserve energy. This study also researches the challenges associated with the implementation of energy management strategies on old gold mines. Research was done on three old gold mines to determine the potential for load shifting on the underground water pumping systems of old gold mines. Integrated simulations were used as the main method of establishing this potential as well as the financial savings potential for the client. The simulation results showed large amounts of load-shifting potential for all three case studies and substantial financial savings potential for the clients. Real-time, load-shifting strategies were implemented on the three systems analysed in the case studies. The results generated by these strategies showed that load shifting could be realised on these systems, and confirmed the potential calculated in the simulations. Further research into the results however showed that the old infrastructure in the old mines caused many problems and influenced the sustainability of these strategies. From this study, the conclusions were made that; (a) there exists a potential for energy management on old gold mines, (b) there exists large potential for the implementation of sustainable energy management strategies on old gold mines, and (c) it is feasible to implement energy management strategies on old gold mines. / Thesis (M.Ing. (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2007

Distributed shared memory (DSM) systems have been recognised as a compelling platform for parallel computing due to the programming advantages and scalability. DSM systems allow applications to access data in a logically shared address space by abstracting away the distinction of physical memory location. As the location of data is transparent, the sources of overhead caused by accessing the distant memories are difficult to analyse. This memory locality problem has been identified as crucial to DSM performance. Many researchers have investigated the problem using simulation as a tool for conducting experiments resulting in the progressive evolution of DSM systems. Nevertheless, both the diversity of architectural configurations and the rapid advance of DSM implementations impose constraints on simulation model designs in two issues: the limitation of the simulation framework on model extensibility and the lack of verification applicability during a simulation run causing the delay in verification process. This thesis studies simulation modelling techniques for memory locality analysis of various DSM systems implemented on top of a cluster of symmetric multiprocessors. The thesis presents a simulation technique to promote model extensibility and proposes a technique for verification applicability, called a Specification-based Parameter Model Interaction (SPMI). The proposed techniques have been implemented in a new interpretation-driven simulation called DSiMCLUSTER on top of a discrete event simulation (DES) engine known as HASE. Experiments have been conducted to determine which factors are most influential on the degree of locality and to determine the possibility to maximise the stability of performance. DSiMCLUSTER has been validated against a SunFire 15K server and has achieved similarity of cache miss results, an average of +-6% with the worst case less than 15% of difference. These results confirm that the techniques used in developing the DSiMCLUSTER can contribute ways to achieve both (a) a highly extensible simulation framework to keep up with the ongoing innovation of the DSM architecture, and (b) the verification applicability resulting in an efficient framework for memory analysis experiments on DSM architecture.

This study predicted that individuals diagnosed as having higher levels of stress, based upon DSM-III-R, Axis IV ratings, would also be diagnosed as having more severe forms of mental illness. Conversely, it predicted that individuals with higher premorbid health ratings, according to DSM-III-R, Axis V, would be diagnosed as having less severe forms of mental illness. Highly significant correlations were found between stress ratings and severity of disorder. Significant inverse relationships were also found between Axis V ratings and disorder severity. Additionally, several other demographic variables were significantly correlated with severity of disorder.

Student Number : 8887128 - PhD thesis - School of Psychology - Faculty of Humanities / There is a manifest similarity between the disorders of deficient attention and borderline psychopathology as they are described in the DSM IV. In my experience, those with borderline psychopathology have a history of problems with attention. This study seeks to explore the experiential link between the two disorders and how deficient attention acts as a precipitant factor in the development of borderline psychopathology. Ten interviews were conducted with adults diagnosed as having borderline personality disorder with a history of deficient attention. The interviews were unstructured, audiotaped and transcribed. The transcriptions were analysed according to the method of thematic content analysis. The transcriptions were also rerepresented in the testimonial form of life history. The data produced seven categories of experience, set in an overall context of trauma. Attention formed only one of these categories. The others were incoherence, incompetence, discord, refraction, dispossession and persecution. The categories, together with existing literature, were linked to form a traumatogenic model of the development of borderline psychopathology. This constitutes an extension of existing literature and is intended to contribute to the prevention and treatment of both disorders.

The predominant model of general personality structure is arguably the Five Factor Model (FFM), consisting of the five broad domains of neuroticism, extraversion, openness, agreeableness, and conscientiousness. The FFM of personality disorder (FFMPD) has proposed maladaptive variants at both poles of the FFM. The purpose of the current study was to identify a subset of FFMPD scales, utilizing factor analysis, that illustrate, and provide a potential measure of, the bipolarity present in the FFMPD. All of the FFMPD scales were administered to 443 community participants recruited from Amazon Mechanical Turk. Bipolarity was evident in a series of factor analyses of subsets of FFMPD scales, with the exception of openness. The current study also demonstrated that the presence of bipolarity is impaired by a number of concerns, including the presence of non-diametric scales, bloated specific factors, general factor of personality disorder, and occupation of interstitial space.

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