Theses and Dissertations (Process Control and Computer Systems)
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Item Design and implementation of a real-time smart sensor network-based system for monitoring potable water quality(Vaal University of Technology, 2022-07-29) Ejike, Christian Nonyelum; Mathaba, T. N. D., Dr.; Ochieng, G. M., Prof.; Ohanga, M. O., Prof.Water is a necessity for living and having clean water is a priority. Lately, the water problem in South Africa has become a concerning subject matter and the risk it poses to livelihood of the people and agriculture cannot be overlooked. The Vaal region has recorded a considerable number of water contamination cases in the Vaal River coupled with a near-drought incident of the Vaal Dam. Water-supply centres are trying their best to uphold the quality of water delivery in the region, however, most of the water treatment facilities are noted to be in a perilous state. Moreover, the traditional methods of water quality assessment used within the region have been deemed untrustworthy and unreliable, given that they are slow, costly and do not necessarily rely on real-time data analysis. These challenges demonstrate that there is a need to rethink the overall water quality monitoring system approach and enhance the assessment methods by taking advantage of the evolution of wireless sensor networks (WSNs) and the Internet of things (IoT), which have led to many applications for environmental monitoring studies. This study demonstrates the viable application of LoRa and LoRaWAN for in-situ water monitoring. A smart autonomous system is proposed that explores the possibility of using IoT technology and the LoRa to monitor, in real-time, the drinking water supplied to communities, assess and log the data remotely and keep authorities up to date about the status of the water supply. The experiment was carried out at the Vanderbijlpark campus of the Vaal University of Technology in Gauteng, South Africa. The transmitting and receiving nodes were modelled after the TTGO LoRa32 board's features. The sensors used are the DS18B20 which monitors temperature, the SEN0161 used for pH and the SEN0189 for turbidity sensing. The tests ran for a duration of three months. The tests demonstrate how the structure of the terrain may impact the covering range, while models that account for building diffraction pinpoint higher attenuation. In comparison to lab simulations from other studies which considers possible path loss effect on LoRa communication in real-life environments, as seen with conventional wireless communication models in both indoor and outdoor settings, four test locations were selected. Multiple measurements of SNR, RSSI are observed as spread factors (SF7-12) are varied for different locations. The result show that the minimum SNR and RSSI value for good transmission were -9.4 dBm and -114 dBm respectively given the same experimental conditions. This can be improved by adding more gateways between paths as recommended as part of future improvement work.Item Development and implementation of hybrid modulation scheme for improving 5G spectrum efficiency(Vaal University of Technology, 2022-08-02) Ovono, Bertille Auyane Ngouessy Ep; Otunniyi, T., Dr.; Ohanga, M. O., Prof.The spectral efficiency variable is one of the issues encountered in wireless and mobile communication systems because of the high demand for data rate traffic. Due to the alarming growth rate of data traffic in the field that requires the high usage of the available spectrum band, the spectrum becomes scarce. This tremendous increase in data traffic could cause congestion issues that will undoubtedly plague wireless networks. Thus, increasing bandwidth or spectral efficiency is critical for 5G communication systems. Hence, the enabling technologies fifth-generation (5G) must consider spectral efficiency. In this paper a hybrid modulation scheme called spatial constant-envelope orthogonal frequency division multiple access (SM-CE-OFDMA) is developed and implemented as an alternative approach to improve spectral efficiency. The performance of the system under AWGN is evaluated in terms of bit error rate, signal-to-noise ratio and peak average-to-power ratio for each main module (OFDMA, CE-OFDMA and SM-CE-ODFMA). The design is simulated on the MATLAB 2020a 5G toolbox. A comparative study is conducted to obtain the BER and SNR of each module transmitted scheme. This comparative study showed that the proposed hybrid outperforms the conventional OFDMA and CE-OFDMA in terms of BER. The hybrid SM-CE-OFDMA reveals to be energy efficient as its SNR increases continuously, so due to the proportional correlation that exists between spectral efficiency and SNR, the proposed hybrid can successfully reach the maximum physical layer rate as the signal strengths become higher, thus resulting in spectral efficiency improvement. Also, simulating the proposed hybrid modulation scheme (SM-CE-OFDMA) has a peak-to-average power ratio (PAPR) value of about 3dB for single carrier, which was acceptable in this work and for the multicarrier, the proposed hybrid decreased PAPR near 0dB for which therefore caused the improvement of spectral and power efficiency. Furthermore, this hybrid SM-CE-OFDMA represented a promising result for the future of bandwidth saving in 5G wireless communication systems.Item Design and implementation of personal health data monitoring and retrieval system for health providers(Vaal University of Technology, 2020-08-17) Ojo-Seriki, D. F.; Mathaba, Tebello N. D., Dr.; Ohanga, M. O., Prof.Personal health record system (PHRS) is a tool that is used in maintaining the health and wellness of an individual as well as helping with illness of an individual. PHRS gives the individual access to a wide range of credible health information, data, and knowledge. Individuals can use that access to improve their health and manage their diseases. Patients with chronic illness can track and manage their health in conjunction with their health provider, this will promote early intervention when they encounter an abnormality or complications. Continuous monitoring and storing of health information has been a challenge for patients and health providers. Personal health data monitoring and retrieval system for health providers was designed and implemented. The main aim of this study was to develop an accurate, secure and flexible personal health data monitoring and retrieval system for health providers (PHRS). This was achieved. The research showed that when a patient health information (Electrocardiogram (ECG) and temperature) was monitored, the heartbeat (ECG) sensor output the value as an analog value to the signal processing (NodeMCU) which was then converted to a digital value. The temperature sensor used in this research is a digital sensor which lowers the amount of ADC conversion that was done. The digital values are displayed on LCD, its send to a personal health data storage system which was designed for health information storage purposes. It also sends the value to a retrieval system which is an android application that is connected to the data storage system to display health information to the health providers from a remote location. Personal health data storage and the retrieval system are secure due to the Message queuing telemetry transport (MQTT) protocol used in the application layer. The MQTT protocol is secure due to the secure socket layer (SSL) which is an encryption based on presentation layer embedded inside the MQTT protocol. After the comparison of the software simulation and the prototype test, the differences in the value for the heartbeat and temperature sensor indicate 0.04 BPM and 0.04 oC which shows the accuracy of the sensing circuit. Personal health data monitoring and retrieval system developed is applicable and useful to multiple entities in and around South Africa such as; Ministry of health, hospitals, sport and recreations.Item Design and implementation of the telecommunication and utility cable tamper monitoring system(Vaal University of Technology, 2019-04-11) Mabadie, Patrick; Ohanga, M. O., Prof.The telecommunication and utility cable monitoring system was implemented to protect the cable tampering. Cable tampering occurs despite the fact that methods have been developed, to solve and decrease cable tampering cases such as cable tampering prevention campaigns at the national and international level, organizing security patrols, replacing existing cable with fiber cables and I-Watch system installation. The objective of the research was to design and implement a cable tampering monitoring system which is able to monitor, detect, pinpoint the location and give the distance from the sensor at which the cable tampering took place. The system is an improvement on the traditional cable anti-theft monitoring system, the method of tracking resonance signal frequency was implemented. The system incorporates a sensing circuit which detects a change on the capacitance value of the cable and converts it into an equivalent frequency value, Field-Programable Gate Array (FPGA) board is utilized to convert the frequency into the cable length (the distance from sensor of cable which was taken away), after detecting an anomaly on the cable (tampered with) the output of the system is divided into two parts which are display mode and messaging mode. For display mode, the system uses a Liquid Crystal Display (LCD) which displays the GPS Coordinates of the location where the cable tampering took place and the distance from sensor of the cable which has been tampered with. In the messaging mode, the FPGA activates the GSM module and the module sends alert flag message to the user when the cable is tampered with.Item Design and implementation of an inventory management system in libraries using radio frequency identification technology(Vaal University of Technology, 2019-12-12) Mvoulabolo, Meryle K.; Mathaba, T. N. D., Dr.; Ohanga, M. O., Prof.Radio Frequency Identification Technology (RFID) technology is increasingly being used in multiple applications due to its low cost and ability to provide a high quality of identification. The cost benefit of RFID system is seen in the reduction in labor required to perform routine tasks such as inventory. With RFID, inventory-related tasks can be done in substantially less time compared to other commonly used auto-identification systems. Recent research has illustrated the application of RFID in multiple application scenarios. RFID can be used for real-time patient identification and monitoring in hospitals, but also for product expiration-date management in retail industries. Some enterprises in South Africa uses a combination of RFID technology and Internet of Things (IoT) to detect misplaced products and to detect low stock levels. Furthermore, RFID is also used for inventory management in libraries as discussed in this dissertation. In this dissertation, a combination of RFID and ZigBee technologies was used to reduce the time spent to perform inventory in libraries. An inventory management system was designed, simulated and built in order to count and locate books inside a library hence improving inventory process time in libraries. The overall results were satisfactory which lead to the achieving of the objectives set in this study.Item Design and implementation of device-to-device communications in next generation mobile networks to counter terrorism in shopping malls(Vaal University of Technology, 2022-02-22) Mwashita, Weston; Ohanga, M. O., Prof.In this research study, a scheme to minimise interference in converged mobile cellular networks (MCNs) and wireless sensor networks (WSNs) was designed and implemented. The focus was the mitigation of interference that arises when proximity service (ProSe)-enabled sensors engage in a device-to device (D2D) communication to alert smartphone users upon the detection of explosives at highly crowded areas like shopping malls. D2D is a technology that academia and industry experts believe will play a prominent role in the implementation of the next generation of mobile networks, specifically, the fifth generation (5G). However, the full roll out of D2D is being impeded by the interference that the technology introduces to the cellular network. D2D devices cause a significant amount of interference to the primary cellular network especially when radio resources are shared. In the downlink phase, primary user equipment is likely to suffer from interference emanating from a D2D transmitter. On the other hand, the immobile base station is affected by interference caused by the D2D transmitter in the uplink phase. This type of interference can be avoided or reduced if radio resources are allocated intelligently under strict coordination of the base station. An NP-hard optimisation problem was formulated and finding a solution to this problem in 1 ms is not possible. 5G has a frame structure duration of 10 ms with 10 subframes of 1 ms each. Heuristic algorithms were then developed to mitigate the interference affecting the primary network that could carry out resource allocation within the fast-scheduling period of 1 ms. Smartphones have progressed into devices capable of generating massive volumes of data. The challenge is that battery technology is not keeping up with the pace of smartphone technology, so any additional feature that designers want to add, is met with a lot of contempt from customers who are concerned about their smartphone batteries depleting rapidly. In this context, the strategy must be energy-efficient for smartphone users to embrace it. A system level simulator was developed using MATLAB to evaluate the efficacy of the proposed design. Extensive simulation results showed that ProSe-enabled sensors can safely be integrated into cellular networks participating in D2D communication with smart phones, without introducing significant harm to the primary cellular network. The results showed that after implementing the proposed strategy, overall user throughput decreased by 3.63 %. In cellular networks, this is a modest figure since a reduction of up to 5% is acceptable to both users and network providers. The figure generally capped in service level agreements signed between network providers and users is 5%. The proposed technique also resulted in a 0 % reduction in SINR of CUEs in a cellular network, according to the findings. In terms of D2D link throughput for different D2D transmit levels, the method proposed in this research work surpassed a similar scheme proposed in literature by an average of 18.3%.Item Plant systems integration using the SAMI model to achieve asset effectiveness in modern plants(2008-05) Joubert, André; Jordaan, A.; Case, M. J.In recent years, industrial plant maintenance has changed dramatically. These changes are due to a considerable increase in the number and variety of physical plant assets, increased design complexity, new maintenance techniques and changing perspectives regarding on how to perform maintenance effectively. Managers at modern process plants are becoming increasingly aware of the extent to which equipment failure affects safety and the environment. Process plant personnel are limited in their ability to accurately and consistently evaluate the health of plant assets. Due to poor record keeping, maintenance staff often has little defence against aging equipment and asset failures. As a result companies have undertaken to implement planned equipment maintenance schedules and install new technology to allow for efficient tracking and analysing of equipment health across the board. The introduction of an integrated asset management solution is presented in this thesis. The integrated asset management solution will assist maintenance staff to cost-effectively predict the probability of asset failure prior to the occurrence of any actual plant incidents. The integrated solution documented in this thesis will be implemented at the Sasol Solvents site to enhance plant availability, maximum up time for all plant assets and plant safety. Strategic Asset Management Inc. (SAMI) uses the Operational Reliability Maturity Continuum model to improve profitability, efficiency and equipment reliability. The SAMI empirical model employs various stages to address improved performance and asset management and was used as a guideline to develop an integrated solution to optimise plant performance and profits. The integrated asset management solution, documented in this thesis, was developed with the intended function of bringing information from diverse plant based systems and field equipment to the maintenance personnel in an understandable interface so that the information can be used to improve the reliability and availability of all plant assets.Item Plant systems integration using the SAMI model to achieve asset effectiveness in modern plants(2010-11-01T09:47:37Z) Joubert, AndrèIn recent years, industrial plant maintenance has changed dramatically. These changes are due to a considerable increase in the number and variety of physical plant assets, increased design complexity, new maintenance techniques and changing perspectives regarding on how to perform maintenance effectively. Managers at modern process plants are becoming increasingly aware of the extent to which equipment failure affects safety and the environment. Process plant personnel are limited in their ability to accurately and consistently evaluate the health of plant assets. Due to poor record keeping, maintenance staff often has little defence against aging equipment and asset failures. As a result companies have undertaken to implement planned equipment maintenance schedules and install new technology to allow for efficient tracking and analysing of equipment health across the board. The introduction of an integrated asset management solution is presented in this thesis. The integrated asset management solution will assist maintenance staff to cost-effectively predict the probability of asset failure prior to the occurrence of any actual plant incidents. The integrated solution documented in this thesis will be implemented at the Sasol Solvents site to enhance plant availability, maximum up time for all plant assets and plant safety. Strategic Asset Management Inc. (SAMI) uses the Operational Reliability Maturity Continuum model to improve profitability, efficiency and equipment reliability. The SAMI empirical model employs various stages to address improved performance and asset management and was used as a guideline to develop an integrated solution to optimise plant performance and profits. The integrated asset management solution, documented in this thesis, was developed with the intended function of bringing information from diverse plant based systems and field equipment to the maintenance personnel in an understandable interface so that the information can be used to improve the reliability and availability of all plant assets.