Thesis (D. Tech. (Electrical Engineering)) - Central University of technology, Free State, 2012 / Radio frequency identification technology (RFID) has emerged as a key technology for automatic identification and promises to revolutionize business processes. While RFID technology adoption is improving rapidly, reliable and widespread deployment of this technology still faces many significant challenges. The key deployment challenges include how to use the simple, unreliable raw data generated by RFID deployments to make business decisions; and how to manage a large number of deployed RFID devices. In this thesis, a multi-agent based RFID middleware which addresses some of the RFID data and device management challenges was developed. The middleware developed abstracts the auto-identification applications from physical RFID device specific details and provides necessary services such as device management, data cleaning, event generation, query capabilities and event persistence. The use of software agent technology offers a more scalable and distributed system architecture for the proposed middleware. As part of a multi-agent system, application-independent domain ontology for RFID devices was developed. This ontology can be used or extended in any application interested with RFID domain ontology. In order to address the event processing tasks within the proposed middleware system, a temporal-based RFID data model which considers both applications’ temporal and spatial granules in the data model itself for efficient event processing was developed. The developed data model extends the conventional Entity-Relationship constructs by adding a time attribute to the model. By maintaining the history of events and state changes, the data model captures the fundamental RFID application logic within the data model. Hence, this new data model supports efficient generation of application level events, updating, querying and analysis of both recent and historical events. As part of the RFID middleware, an adaptive sliding-window based data cleaning scheme for reducing missed readings from RFID data streams (called WSTD) was also developed. The WSTD scheme models the unreliability of the RFID readings by viewing RFID streams as a statistical sample of tags in the physical world, and exploits techniques grounded in sampling theory to drive its cleaning processes. The WSTD scheme is capable of efficiently coping with both environmental variations and tag dynamics by automatically and continuously adapting its cleaning window size, based on observed readings.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2009

Thesis (M. Tech.) - Central University of Technology, Free State, 2008

Thesis(M. Tech.) - Central University of Technology, Free State, 2004 / Growing markets leads to an increase in production. In these modern industries, weight measurement is of high priority. Weight measurement instrumentation is used for quality control, as well as for effective process control. Ineffective instrumentation with inaccurate data will influence the production process and profit margins negatively. Experimental data is gathered from an angled load cell, placed as a crossover between two conveyer belts. A weight measurement instrument with the ability to acquire accurate measurement of individual, moving parts is produced with the aid of DSP techniques. This was accomplished by analyzing the frequency spectrum for the undesirable signals with the use of Wavelets transformations (WT) and Fourier transformations (FT). After these undesired signals were identified a digital filter was designed to remove the undesired signals. Repetition of performance is achieved by the automatic zeroing of the instrument after every individual measurement. This weight measurement instrumentation also has the ability to store data consisting of the amount of objects and their individual weights. This instrument can also determine the material of which an object is made of. This is done by calculating the friction coefficient. This function has the ability to effectively identify between iron and rubber components irrespective of their mass or area.

Thesis (M. Tech.) - Central University of Technology, Free State, 2006 / Demand-side management (DSM) is one of the integrated energy planning concepts that has only recently been introduced in South Africa. This concept needs to be fully developed in order to suit current industrial development situations. South Africa’s coal and water reserves will not last forever because of the growing population and the accompanying demands on our energy resources {[5] of Chapter 1]}. Therefore the demand-side interventions are considered on an effective means of overcoming these problems. The traditional approach of electrical energy utilisation by Eskom and its customers has to be reviewed. Socio-economic and environmental development benefits must also be reviewed. Advanced research on demand-side management has benefited the international world tremendously and this kind of research should also be done in South Africa. The research project for this study as described from chapter 1- 8 was undertaken to show the potential implementation of demand-side management and its interventions (DSM programme) on the Theunissen-Brandfort Pumps 11kV feeder (TBP). This would result in the generating of potential energy and cost-savings that would flow from the feasible DSM programme. This would be measured and verified by billing the actual saved energy at the TBP electrical system for the future. Every potentially saved-energy means one less potential reduction in emission. The case studies were conducted on Eskom’s entire TBP network and on four large power users which were identified and which provided the relevant potential results. Methodological design protocol processes for best-practice pollution prevention and the efficiency-energy (EE) audit protocol model, with its accompanying goal and objectives were used. The project concentrated on EE and time-of-use (TOU) factors related to the selected customers and the TBP as a whole, thus: potential Replacement and Rewinding of low efficiency with higher efficiency motors and the TBP feeder potential Load-Shifting. The stages within the EE, LS and DSM project process which were used for potential implementation are the following: project identification, energy audits and assumptions and recommendations for implementation. The M&V interaction with DSM, EE or LS project processes (methodology) for future implementation purposes (actual retrofitting) is also shown. The TBP feeder collective baseline (Figure 6.2) was quantified by trapezium rule. The feasible EE and LS programmes opportunities analysis on motors and the entire TBP were performed by inference and stipulation techniques and the potential energy reduction effects using a simulation programme called International Motor Selection and Savings Analysis (IMSSA). The potential LS programme was also performed based on the Eskom’s miniflex tariff defined time of use. TBP plant-wide EE and LS assessments conducted with the methodology mentioned, identified and quantified a total of two EE savings opportunities and were divided into four categories: those for short-term, long-term, none and best solution potential implementations (Table 7.9). As far as indirect results are concerned, DSM is a very new concept in South Africa and is consequently not well known. The study was based on simplicity in order to make the DSM subject very simple and easily accessible to future research. By using a simple and userfriendly IMSSA software programme, quick, relevant results were obtained. The study played an important role in influencing and educating interested parties about the importance of potential demand-side management concepts and objectives. The study compiled valuable information on EE, DSM (LS) and M&V that was previously unknown and, which will make future research much more accessible and manageable. It is recommended that all the motors identified as inefficient be rewound and replaced by new and efficient ones in the future. It is also very important that the potential LS programme be implemented only after these potential EE opportunities are implemented so that there will be sustainability and the DSM objectives may be achieved (Table 7.10). The project led to better grasp of electric energy consumption by the customers. From a socio-economic perspective, Eskom can distribute the surplus potentially saved energy of capacity at the TBP to other communities, which would also create employment if a new network could be built. Allocation of potentially saved energy to other population groups or customers of low-income groups in the Theunissen area would mean a significant lifestyle change. With regard to environmental benefits, previous research has proven that for every kWh of electricity saved, fewer emissions (e.g. C02) would be generated at the power station. The study addressed TBP-wide power use, focusing primarily on the demand-side interventions, but implications for improvements in the supply-side emission reductions were also considered.

Thesis (D. Tech)--Central University of Technology, Free State, 2008 / The global, one-world economy has arrived and South Africa is part of it. Business needs to understand the challenge of global competitiveness. This study reflected the prominence of managing diversity in establishing service excellence and performance management for professionals in the mediumsize chicken breeder/broiler industry in South Africa, following the increased importance of the breeder/broiler industry in providing an affordable nutriment/commodity to the poor and needy South African population. The ongoing variables in the political, social, cultural and technology domains in South Africa also affect the chicken breeder/broiler industry. It necessitates the scientific evaluation of the effect of the external political and socio-political environment; internal training and development, leadership styles, literacy levels, employment equity, resistance to change, reverse discrimination and cultural diversity on service excellence and performance. Country Bird (Pty) Ltd., a significant role-player in the food production industry, was thus selected as the object of this study. The role of management and the workers was examined to determine the level of impact in attaining service excellence and organisational performance. Attention was also focused on the development of a service excellence and organisational performance management model that can be used in the chicken breeder/broiler industry to improve organisational performance and sustainable profits.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2008 / Motivated by the challenges associated with demonstrating the cervicothoracic junction, a study was conducted at Pelonomi Regional Hospital from May 2006 to June 2007. In this study, two projections of the cervicothoracic junction were done, with the only difference between them being the orientation of the arms. One projection was done using the swimmer’s projection and the other using an adaptation of the swimmer’s projection where the orientation of the arms was reversed. The sample, consisting of 45 patients, was referred from the emergency department and wards. Most of the patients (95.5%) were examined using a computed radiography system providing digital images that were printed using a laser film printer. Other patients were examined using conventional film/screen systems. The objectives of this study were to compare the two imaging techniques with reference to diagnostic quality of the projections, diagnosis of pathology and repeat rate. Radiographers obtained the two projections of the cervical spine; the researcher collected the images and distributed these to three participating radiologists on a rotational basis. The radiologists evaluated the films using a set of criteria; a biostatistician analysed the results of these evaluations. In all the criteria of image quality the swimmer’s projection showed better results. There were also, however, instances where the adapted swimmer’s had better results. The differences in percentages were not significant enough to show any statistical difference between the resultant images of the two techniques. No valid deduction could be made in relation to the demonstration of pathology due to variable instances of pathology evaluated by the radiologists. The repeat rate of the adapted swimmer’s projection compared well with the swimmer’s projection. Though the swimmer’s projection had better results for most of the criteria used in this study, no unequivocal, statistically significant evidence of it demonstrating C7-T1 better could be found. What was evident was the validity of the adapted swimmer’s projection as an alternative under certain conditions. Knowing that there is an alternative method to visualising the C7- T1 junction could be beneficial not only to radiography, but also to our patients. In cases where the swimmer’s projection is not possible due to extremity injuries, an alternative arm orientation can be useful. The alternative can also address the problem regarding multiple repeats of the swimmer’s projection.

Thesis (M. Tech. (Agric. Animal Prod.)) -- Central University of technology, Free State, 2009 / The objective of this study was to evaluate the viability of semen extended in “Umqombothi” (UMQ) and compare with Beltsville Thawing Solution (BTS) and unextended semen (UNX). Twelve large white boars and twelve large white sows were used in this experiment. The following sperm characteristics were measured; sperm motility percentage, live sperm, sperm concentration, abnormal sperm percentage and semen pH of (UNX), (UMQ) and (BTS) and compared, fertility parameters namely; non-return rate percentage, farrowing rate, total piglets and live piglets were also measured and compared. The results from the study showed a significant difference (p<0.05) in sperm motility between (UNX), (UMQ) and (BTS) whereby (UMQ) had the highest percentage of motile sperm which was followed by (BTS) and (UNX) having the lowest percentage of motile sperm, however the results also showed that sperm motility and live sperm percentage of semen stored at 4°C differed significantly (p<0.05) from sperm motility and live sperm percentage of semen stored at 25°C whereby sperm motility and live sperm percentage of semen stored at 25°C were higher than sperm motility and live sperm percentage of semen stored at 4°C. Nevertheless no significant difference in sperm concentration and semen pH was found when semen stored at 4°C and 25°C were compared. However were time of semen collection of 9:00 and 15:00 were compared no significant differences in sperm motility percentage, live sperm percentage, sperm concentration, abnormal sperm percentage and semen pH were observed. The study also revealed a significant difference (p<0.05) in non-return rate, farrowing rate, total piglets and live piglets between semen stored at 25°C and 4°C of which the results explain that semen stored at 25°C had a higher percentage of non-return rate , farrowing rate, total piglets and live piglets, however, Under (UNX) collected at 9:00 and 15:00 that there was no significant difference in no-return rate percentage, farrowing rate, total piglets and live piglets was observed when two times of semen collections were compared. Under (UMQ) collected at 9:00 and 15:00 there was also no significant difference in non-return rate percentage, farrowing rate, total piglets and live piglets observed when two times of semen collections were compared. Under (BTS) collected at 9:00 and 15:00 there was also no significant difference in non-return rate percentage, farrowing rate, total piglets and live piglets observed when two times of semen collections were compared. Nevertheless were semen extenders were compared (UNX) collected at 9:00 and 15:00 differed significantly (p<0.05) from (UMQ) and (BTS) collected at 9:00 and 15:00 whereby (UNX) had the lowest percentage of non-return rate, farrowing rate, total piglets and live piglets.

Thesis (M. Tech. Agriculture) -- Central University of Technology, Free state, 2012 / Low lifetime rearing success and high perinatal mortality have been associated with small pelvic areas of ewes. Ewes with small pelvic areas are more prone to experience dystocia during parturition and high perinatal mortality. It would thus make sense to include pelvic area as criterion in selecting breeding animals (rams) in an attempt to assure bigger pelvic areas in the female progeny as the heritability of pelvic area ranges between 50-60%. The aims of this study were to develop two instruments to accurately measure the pelvic area and rump slope in small stock, to investigate the hindquarter dimensions and to quantify the relationship between a number of easy to measure external body measurements and pelvic dimensions of Dorper sheep. The pelvic meter developed was pre-tested on 90 sheep prior to slaughtering at an abattoir and shortly after slaughter. The correlation between the pre- and post- slaughter measurements was highly significant (P <0.05; r = 0.85). In this study 272 Dorper and White Dorper rams (5-7 months of age) participating in the Northern Cape Veldram project and 332 young Dorper and White Dorper ewes (±12 months of age) from three different breeders were measured. The inside pelvic area was measured trans-rectally. The rams’ pelvic areas were measured five times transrectally, at 40 days intervals between the ages of 223 ± 41 and 385 ± 41 days of age. The height of the pelvis was obtained by measuring the distance between the dorsal pubic tubercle on the floor of the pelvis and the sacrum (spinal column) on the top. The width of the pelvis was measured as the widest distance, between the right and the left shafts of the ilium bones. The pelvic area was calculated using the π (PH/2)*(PW/2) formula. Other linear body measurements (body height, shoulder height, chest depth, forequarter width, hindquarter width, rump length) as well as body weight were taken. The rams’ rump slope was measured in degrees with an instrument that was developed for this purpose, and the ewes’ rump slope was visually scored on a scale from 1-5 with one being very flat and five being very droopy. The overall mean pelvic area of ewes 35.44 ± 4.89 cm2 and those of the rams 28.22 ± 3.21 cm2 differed with 7.22 cm2. Stud ewes recorded significantly larger (P <0.05) pelvic areas (37.38 ± 4.3 cm2) than commercial ewes (33.92 ± 3.77cm2). Results indicated that there are no significant correlations between pelvic dimensions and other body measurements considered in this study, indicating the need to measure pelvic area directly. Both the pelvic meter and rump slope meter, specially developed for this study, proved to be accurate and relatively practical to use in Dorper sheep.

Thesis (M. Tech. Environmental health) -- Central University of technology, Free State, 2011 / Although the application of low pH is common practice in food preservation, the emergence of acid tolerance has been reported world-wide amidst a growing concern that preservation with weak acids, such as organic acids may be influenced as a result of food-borne bacteria becoming acid tolerant or acid resistant. The present study was conducted to assess the acid tolerance of a wide range of bacterial species and consequently the sustainable application of organic acids as food preservatives in particularly acidic foodstuffs. Acid tolerance was determined in 19 bacterial strains predominantly associated with food spoilage and food poisoning. After exposure to hydrochloric acid 16% of the isolates were found to be intrinsically tolerant to low pH and included amongst others the enteric bacteria Escherichia coli and Salmonella spp. The latter organisms are known causative agents in food spoilage and poisoning, and the results highlight the predicaments related to their ability to survive in acidic foodstuffs as well as the human gastric environment. Bacterial strains were further exposed to increasing concentrations of various acidic foodstuffs in order to determine the development of acid tolerance by gradual decrease in pH, as opposed to exposure to acid shock. After induction, the protein profiles of resulting acid tolerant isolates were compared with those of the original un-induced strains. Exposure to acidic foodstuffs resulted in various survival profiles, where not only pH but also the type of acidulant (foodstuff or inorganic acid) were found to be contributing factors in acid tolerance development. Bacterial protein composition after exposure to acidic foodstuffs showed considerable variation which may be indicative of acid tolerance development whereas the mechanisms involved may be the result of multiple modifications in bacterial composition. After the induction of acid tolerance, susceptibility of induced strains to various organic acids were determined at various pH values. This was done to investigate whether acid tolerance would influence the inhibitory activity of organic acids as antimicrobial agents in acidic food. Decreased susceptibility was not significantly demonstrated with the exception of only selected isolates, the latter including E. coli and S. typhimurium. Organic acid activity was found to be much more effective at lower pH values and it would be necessary to elucidate whether this inhibition is the result of a lower pH or more specifically the activity of the organic acids. The effect of exposure to an acidic environment on phenotypic characteristics of Gram-negative bacteria, and more specifically psychrotrophic organisms was evaluated in order to show the combined effect of organic acids and low temperature preservation. The characteristic yellow pigment of various Chryseobacterium species was found to be not as apparent after acid exposure while in some cases the colonies were observed as white. In Pseudomonas aeruginosa the characteristic green pigment was much more prominent after acid exposure. These morphological alterations may be important factors that should be considered in identification procedures employed in food safety laboratories. Finally, the influence of acidic exposure via acidic foodstuffs and also organic acids on the protein composition and outer membrane protein structure of various bacterial cells was investigated. No specific relationships with the MICs (Minimum Inhibitory Concentrations) of organic acids after induction with the selected acidic foodstuffs could be established, although various differences were found in protein expression. From the results, it may be suggested that the outer membrane of various pathogenic bacteria is involved in acid tolerance development and this supports the reports on the importance of membrane integrity in the protection against low pH. In conclusion, the study endeavoured to add to the body of knowledge with regard to alternative food preservation regimes utilising organic acids, either solely or in combination with selected extrinsic and intrinsic parameters.