Wireless rotational process monitoring system
- Authors: Odendaal, Morné
- Date: 2011
- Subjects: Manufacturing processes -- Automation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9599 , http://hdl.handle.net/10948/1347 , Manufacturing processes -- Automation
- Description: The manufacturing industry is constantly looking for ways to reduce production costs and at the same time to increase productivity. Automation of common manufacturing operations is one of these methods. By automating common manufacturing operations; various machines, robots, control systems and information technologies are used to reduce the overall human input requirement (mental and physical). Recent advances in technology have made it possible to now also automate (or facilitate) the maintenance requirement of these machines and tools. Modern tools and machines, which can estimate when it will fail or when failure is imminent have obvious advantages for predictive maintenance purposes. Another function of this technology is to determine how efficiently a tool or machine operates, or what the quality of the produced goods is. Predictive maintenance can decrease manufacturing plant or machine down times – which have a positive effect on cost-savings – has gained considerable importance over the last two decades.
- Full Text:
- Date Issued: 2011
- Authors: Odendaal, Morné
- Date: 2011
- Subjects: Manufacturing processes -- Automation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9599 , http://hdl.handle.net/10948/1347 , Manufacturing processes -- Automation
- Description: The manufacturing industry is constantly looking for ways to reduce production costs and at the same time to increase productivity. Automation of common manufacturing operations is one of these methods. By automating common manufacturing operations; various machines, robots, control systems and information technologies are used to reduce the overall human input requirement (mental and physical). Recent advances in technology have made it possible to now also automate (or facilitate) the maintenance requirement of these machines and tools. Modern tools and machines, which can estimate when it will fail or when failure is imminent have obvious advantages for predictive maintenance purposes. Another function of this technology is to determine how efficiently a tool or machine operates, or what the quality of the produced goods is. Predictive maintenance can decrease manufacturing plant or machine down times – which have a positive effect on cost-savings – has gained considerable importance over the last two decades.
- Full Text:
- Date Issued: 2011
Wireless industrial intelligent controller for a non-linear system
- Authors: Fernandes, John Manuel
- Date: 2015
- Subjects: Neural networks (Computer science) , Linear systems
- Language: English
- Type: Thesis , Masters , MEngineering (Mechatronics)
- Identifier: http://hdl.handle.net/10948/9021 , vital:26457
- Description: Modern neural network (NN) based control schemes have surmounted many of the limitations found in the traditional control approaches. Nevertheless, these modern control techniques have only recently been introduced for use on high-specification Programmable Logic Controllers (PLCs) and usually at a very high cost in terms of the required software and hardware. This ‗intelligent‘ control in the sector of industrial automation, specifically on standard PLCs thus remains an area of study that is open to further research and development. The research documented in this thesis examined the effectiveness of linear traditional control schemes such as Proportional Integral Derivative (PID), Lead and Lead-Lag control, in comparison to non-linear NN based control schemes when applied on a strongly non-linear platform. To this end, a mechatronic-type balancing system, namely, the Ball-on-Wheel (BOW) system was designed, constructed and modelled. Thereafter various traditional and intelligent controllers were implemented in order to control the system. The BOW platform may be taken to represent any single-input, single-output (SISO) non-linear system in use in the real world. The system makes use of current industrial technology including a standard PLC as the digital computational platform, a servo drive and wireless access for remote control. The results gathered from the research revealed that NN based control schemes (i.e. Pure NN and NN-PID), although comparatively slower in response, have greater advantages over traditional controllers in that they are able to adapt to external system changes as well as system non-linearity through a process of learning. These controllers also reduce the guess work that is usually involved with the traditional control approaches where cumbersome modelling, linearization or manual tuning is required. Furthermore, the research showed that online-learning adaptive traditional controllers such as the NN-PID controller which maintains the best of both the intelligent and traditional controllers may be implemented easily and with minimum expense on standard PLCs.
- Full Text:
- Date Issued: 2015
- Authors: Fernandes, John Manuel
- Date: 2015
- Subjects: Neural networks (Computer science) , Linear systems
- Language: English
- Type: Thesis , Masters , MEngineering (Mechatronics)
- Identifier: http://hdl.handle.net/10948/9021 , vital:26457
- Description: Modern neural network (NN) based control schemes have surmounted many of the limitations found in the traditional control approaches. Nevertheless, these modern control techniques have only recently been introduced for use on high-specification Programmable Logic Controllers (PLCs) and usually at a very high cost in terms of the required software and hardware. This ‗intelligent‘ control in the sector of industrial automation, specifically on standard PLCs thus remains an area of study that is open to further research and development. The research documented in this thesis examined the effectiveness of linear traditional control schemes such as Proportional Integral Derivative (PID), Lead and Lead-Lag control, in comparison to non-linear NN based control schemes when applied on a strongly non-linear platform. To this end, a mechatronic-type balancing system, namely, the Ball-on-Wheel (BOW) system was designed, constructed and modelled. Thereafter various traditional and intelligent controllers were implemented in order to control the system. The BOW platform may be taken to represent any single-input, single-output (SISO) non-linear system in use in the real world. The system makes use of current industrial technology including a standard PLC as the digital computational platform, a servo drive and wireless access for remote control. The results gathered from the research revealed that NN based control schemes (i.e. Pure NN and NN-PID), although comparatively slower in response, have greater advantages over traditional controllers in that they are able to adapt to external system changes as well as system non-linearity through a process of learning. These controllers also reduce the guess work that is usually involved with the traditional control approaches where cumbersome modelling, linearization or manual tuning is required. Furthermore, the research showed that online-learning adaptive traditional controllers such as the NN-PID controller which maintains the best of both the intelligent and traditional controllers may be implemented easily and with minimum expense on standard PLCs.
- Full Text:
- Date Issued: 2015
Wireless ICT monitoring for hydroponic agriculture
- Authors: Ndame, Loic Andre Stephane
- Date: 2015
- Subjects: Mobile apps -- South Africa , Hydroponics -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/3605 , vital:20445
- Description: It is becoming increasingly evident that agriculture is playing a pivotal role in the socio-economic development of South Africa. The agricultural sector is important because it contributes approximately 2% to the gross domestic product of the country. However, many factors impact on the sustainability of traditional agriculture in South Africa. Unpredictable climatic conditions, land degradation and a lack of information and awareness of innovative farming solutions are among the factors plaguing the South African agricultural landscape. Various farming techniques have been looked at in order to mitigate these challenges. Among these interventions are the introduction of organic agriculture, greenhouse agriculture and hydroponic agriculture, which is the focus area of this study. Hydroponic agriculture is a method of precision agriculture where plants are grown in a mineral nutrient solution instead labour- intensive activity that requires an incessant monitoring of the farm environment in order to ensure a successful harvest. Hydroponic agriculture, however, presents a number of challenges that can be mitigated by leveraging the recent mobile Information and Communication Technologies (ICTs) breakthroughs. This dissertation reports on the development of a wireless ICT monitoring application for hydroponic agriculture: HydroWatcher mobile app. HydroWatcher is a complex system that is composed of several interlacing parts and this study will be focusing on the development of the mobile app, the front-end of the system. This focus is motivated by the fact that in such systems the front-end, being the part that the users interact with, is critical for the acceptance of the system. However, in order to design and develop any part of HydroWatcher, it is crucial to understand the context of hydroponic agriculture in South Africa. Therefore, complementary objectives of this study are to identify the critical factors that impact hydroponic agriculture as well as the challenges faced by hydroponic farmers in South Africa. Thus, it leads to the elicitation of the requirements for the design and development of HydroWatcher. This study followed a mixed methods approach, including interviews, observations, exploration of hydroponic farming, to collect the data, which will best enable the researcher to understand the activities relating to hydroponic agriculture. A qualitative content analysis was followed to analyse the data and to constitute the requirements for the system and later to assert their applicability to the mobile app. HydroWatcher proposes to couple recent advances in mobile technology development, like the Android platform, with the contemporary advances in electronics necessary for the creation of wireless sensor nodes, as well as Human Computer interaction guidelines tailored for developing countries, in order to boost the user experience.
- Full Text:
- Date Issued: 2015
- Authors: Ndame, Loic Andre Stephane
- Date: 2015
- Subjects: Mobile apps -- South Africa , Hydroponics -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/3605 , vital:20445
- Description: It is becoming increasingly evident that agriculture is playing a pivotal role in the socio-economic development of South Africa. The agricultural sector is important because it contributes approximately 2% to the gross domestic product of the country. However, many factors impact on the sustainability of traditional agriculture in South Africa. Unpredictable climatic conditions, land degradation and a lack of information and awareness of innovative farming solutions are among the factors plaguing the South African agricultural landscape. Various farming techniques have been looked at in order to mitigate these challenges. Among these interventions are the introduction of organic agriculture, greenhouse agriculture and hydroponic agriculture, which is the focus area of this study. Hydroponic agriculture is a method of precision agriculture where plants are grown in a mineral nutrient solution instead labour- intensive activity that requires an incessant monitoring of the farm environment in order to ensure a successful harvest. Hydroponic agriculture, however, presents a number of challenges that can be mitigated by leveraging the recent mobile Information and Communication Technologies (ICTs) breakthroughs. This dissertation reports on the development of a wireless ICT monitoring application for hydroponic agriculture: HydroWatcher mobile app. HydroWatcher is a complex system that is composed of several interlacing parts and this study will be focusing on the development of the mobile app, the front-end of the system. This focus is motivated by the fact that in such systems the front-end, being the part that the users interact with, is critical for the acceptance of the system. However, in order to design and develop any part of HydroWatcher, it is crucial to understand the context of hydroponic agriculture in South Africa. Therefore, complementary objectives of this study are to identify the critical factors that impact hydroponic agriculture as well as the challenges faced by hydroponic farmers in South Africa. Thus, it leads to the elicitation of the requirements for the design and development of HydroWatcher. This study followed a mixed methods approach, including interviews, observations, exploration of hydroponic farming, to collect the data, which will best enable the researcher to understand the activities relating to hydroponic agriculture. A qualitative content analysis was followed to analyse the data and to constitute the requirements for the system and later to assert their applicability to the mobile app. HydroWatcher proposes to couple recent advances in mobile technology development, like the Android platform, with the contemporary advances in electronics necessary for the creation of wireless sensor nodes, as well as Human Computer interaction guidelines tailored for developing countries, in order to boost the user experience.
- Full Text:
- Date Issued: 2015
VoIP : a corporate governance approach to avoid the risk of civil liability
- Authors: Gerber, Tian Johannes
- Date: 2012
- Subjects: Internet telephony -- Security measures , Telecommunication policy -- South Africa , Computer network protocols -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9812 , http://hdl.handle.net/10948/d1016272
- Description: Since the deregulation of Voice over Internet Protocol (VoIP) in 2005, many South African organizations are now attempting to leverage its cost saving and competitive values. However, it has been recently cited that VoIP is one of the greatest new risks to organizations and this risk is cited to increase Information Security insurance premiums in the near future. Due to the dynamic nature of the VoIP technology, regulatory and legislative concerns such as lawful interception of communications and privacy may also contribute to business risk. In order to leverage value from the VoIP implementation, an organization should implement the technology with knowledge of the potential risk of civil liability. This is further highlighted by the King III Report which indicates that the Directors of an organization should be ultimately responsible for Corporate Governance and, therefore, IT Governance and Information Security Governance. The report goes further to say that any newly implemented technology, such as VoIP, should comply with all South African legislation and regulations. This responsibility encourages the practice of both due care and due diligence. However, recent trends exercised by Information Security professionals, responsible for drafting Information Security policies and related procedures, often neglect the regulatory requirements and choose to only implement international best practices with no consideration of the risk of civil liability. Although these best practice frameworks may inadvertently comply with existing local legislation, a chance of an oversight is possible. Oversights may not only result in criminal sanctions, but also civil action due to losses or damages suffered. With regard to implementing VoIP, good Corporate Governance could potentially be ensured through the use of both identified regulations and relevant international best practices. This dissertation aims to aid organizations in avoiding or at least mitigating the risk of civil liability to better leverage VoIP’s value, through good Corporate Governance practices. This should aid in the exercise of due care and due diligence when implementing VoIP as a means of conducting business communication.
- Full Text:
- Date Issued: 2012
- Authors: Gerber, Tian Johannes
- Date: 2012
- Subjects: Internet telephony -- Security measures , Telecommunication policy -- South Africa , Computer network protocols -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9812 , http://hdl.handle.net/10948/d1016272
- Description: Since the deregulation of Voice over Internet Protocol (VoIP) in 2005, many South African organizations are now attempting to leverage its cost saving and competitive values. However, it has been recently cited that VoIP is one of the greatest new risks to organizations and this risk is cited to increase Information Security insurance premiums in the near future. Due to the dynamic nature of the VoIP technology, regulatory and legislative concerns such as lawful interception of communications and privacy may also contribute to business risk. In order to leverage value from the VoIP implementation, an organization should implement the technology with knowledge of the potential risk of civil liability. This is further highlighted by the King III Report which indicates that the Directors of an organization should be ultimately responsible for Corporate Governance and, therefore, IT Governance and Information Security Governance. The report goes further to say that any newly implemented technology, such as VoIP, should comply with all South African legislation and regulations. This responsibility encourages the practice of both due care and due diligence. However, recent trends exercised by Information Security professionals, responsible for drafting Information Security policies and related procedures, often neglect the regulatory requirements and choose to only implement international best practices with no consideration of the risk of civil liability. Although these best practice frameworks may inadvertently comply with existing local legislation, a chance of an oversight is possible. Oversights may not only result in criminal sanctions, but also civil action due to losses or damages suffered. With regard to implementing VoIP, good Corporate Governance could potentially be ensured through the use of both identified regulations and relevant international best practices. This dissertation aims to aid organizations in avoiding or at least mitigating the risk of civil liability to better leverage VoIP’s value, through good Corporate Governance practices. This should aid in the exercise of due care and due diligence when implementing VoIP as a means of conducting business communication.
- Full Text:
- Date Issued: 2012
Vision-guided tracking of complex tree-dimensional seams for robotic gas metal arc welding
- Authors: Hamed, Maien
- Date: 2011
- Subjects: Robot vision , Robotics , Gas metal arc welding
- Language: English
- Type: Thesis , Masters , MEngineering (Mechatronics)
- Identifier: vital:9646 , http://hdl.handle.net/10948/1428 , Robot vision , Robotics , Gas metal arc welding
- Description: Automation of welding systems is often restricted by the requirements of spatial information of the seams to be welded. When this cannot be obtained from the design of the welded parts and maintained using accurate xturing, the use of a seam teaching or tracking system becomes necessary. Optical seam teaching and tracking systems have many advantages compared to systems implemented with other sensor families. Direct vision promises to be a viable strategy for implementing optical seam tracking, which has been mainly done with laser vision. The current work investigated direct vision as a strategy for optical seam teaching and tracking. A robotic vision system has been implemented, consisting of an articulated robot, a hand mounted camera and a control computer. A description of the calibration methods and the seam and feature detection and three-dimensional scene reconstruction is given. The results showed that direct vision is a suitable strategy for seam detection and learning. A discussion of generalizing the method used as an architecture for simultanious system calibration and measurement estimation is provided.
- Full Text:
- Date Issued: 2011
- Authors: Hamed, Maien
- Date: 2011
- Subjects: Robot vision , Robotics , Gas metal arc welding
- Language: English
- Type: Thesis , Masters , MEngineering (Mechatronics)
- Identifier: vital:9646 , http://hdl.handle.net/10948/1428 , Robot vision , Robotics , Gas metal arc welding
- Description: Automation of welding systems is often restricted by the requirements of spatial information of the seams to be welded. When this cannot be obtained from the design of the welded parts and maintained using accurate xturing, the use of a seam teaching or tracking system becomes necessary. Optical seam teaching and tracking systems have many advantages compared to systems implemented with other sensor families. Direct vision promises to be a viable strategy for implementing optical seam tracking, which has been mainly done with laser vision. The current work investigated direct vision as a strategy for optical seam teaching and tracking. A robotic vision system has been implemented, consisting of an articulated robot, a hand mounted camera and a control computer. A description of the calibration methods and the seam and feature detection and three-dimensional scene reconstruction is given. The results showed that direct vision is a suitable strategy for seam detection and learning. A discussion of generalizing the method used as an architecture for simultanious system calibration and measurement estimation is provided.
- Full Text:
- Date Issued: 2011
Using vehicle activated signs as an integrated measure to improve road safety in South Africa
- Authors: Swanepoel, Charl
- Date: 2015
- Subjects: Traffic signs and signals -- South Africa , Electronic traffic controls
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/3745 , vital:20460
- Description: Road safety is an aspect of major concern on road networks, not only on a local scale in South Africa, but also on a global scale. South Africa is experiencing an unacceptably high rate of fatal road traffic crashes and as a result has one of the highest per capita rate of road fatalities in the world. The Global Plan for the Decade of Action for Road Safety 2011 – 2020 was published in 2011 by the World Health Organisation (WHO) to guide and assist countries with the improvement of road safety. The management of vehicle speeds is one of numerous important interventions identified in the Global Plan. The technical and economic feasibility of using a specific Road safety is an aspect of major concern on road networks, not only on a local scale in South Africa, but also on a global scale. South Africa is experiencing an unacceptably high rate of fatal road traffic crashes and as a result has one of the highest per capita rate of road fatalities in the world. The Global Plan for the Decade of Action for Road Safety 2011 – 2020 was published in 2011 by the World Health Organisation (WHO) to guide and assist countries with the improvement of road safety. The management of vehicle speeds is one of numerous important interventions identified in the Global Plan. The technical and economic feasibility of using a specific technology, namely Vehicle Activated Signs (VAS), to contribute to the overall improvement of road safety on a national level in South Africa were investigated, with particular emphasis on the improvement of road safety through the reduction of fatal road traffic crashes. VAS are part of a range of measures that can be used to curb vehicle speeds, similar to conventional measures like speed cameras and traffic calming devices. VAS technology has seen limited use in South extrapolation of results from SCC’s VAS effectiveness study, and the application of these results to the South African road safety and road user statistics for the one year period March 2011 to March 2012. Key factors relating to speed and general driver obedience were also taken into consideration. It was established that the use of VAS would lead to a moderate reduction in the number of fatal road traffic crashes that occur annually, which in turn holds financial and socio-economic benefits for South Africa. A comparison of selected products available from two South African based electronic road sign manufacturing companies with conventional VAS was also carried out, focussing on product function, use and cost. It has been concluded that it would be technically and economically feasible to introduce VAS on the South African road network to improve the prevailing road safety situation.
- Full Text:
- Date Issued: 2015
- Authors: Swanepoel, Charl
- Date: 2015
- Subjects: Traffic signs and signals -- South Africa , Electronic traffic controls
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/3745 , vital:20460
- Description: Road safety is an aspect of major concern on road networks, not only on a local scale in South Africa, but also on a global scale. South Africa is experiencing an unacceptably high rate of fatal road traffic crashes and as a result has one of the highest per capita rate of road fatalities in the world. The Global Plan for the Decade of Action for Road Safety 2011 – 2020 was published in 2011 by the World Health Organisation (WHO) to guide and assist countries with the improvement of road safety. The management of vehicle speeds is one of numerous important interventions identified in the Global Plan. The technical and economic feasibility of using a specific Road safety is an aspect of major concern on road networks, not only on a local scale in South Africa, but also on a global scale. South Africa is experiencing an unacceptably high rate of fatal road traffic crashes and as a result has one of the highest per capita rate of road fatalities in the world. The Global Plan for the Decade of Action for Road Safety 2011 – 2020 was published in 2011 by the World Health Organisation (WHO) to guide and assist countries with the improvement of road safety. The management of vehicle speeds is one of numerous important interventions identified in the Global Plan. The technical and economic feasibility of using a specific technology, namely Vehicle Activated Signs (VAS), to contribute to the overall improvement of road safety on a national level in South Africa were investigated, with particular emphasis on the improvement of road safety through the reduction of fatal road traffic crashes. VAS are part of a range of measures that can be used to curb vehicle speeds, similar to conventional measures like speed cameras and traffic calming devices. VAS technology has seen limited use in South extrapolation of results from SCC’s VAS effectiveness study, and the application of these results to the South African road safety and road user statistics for the one year period March 2011 to March 2012. Key factors relating to speed and general driver obedience were also taken into consideration. It was established that the use of VAS would lead to a moderate reduction in the number of fatal road traffic crashes that occur annually, which in turn holds financial and socio-economic benefits for South Africa. A comparison of selected products available from two South African based electronic road sign manufacturing companies with conventional VAS was also carried out, focussing on product function, use and cost. It has been concluded that it would be technically and economically feasible to introduce VAS on the South African road network to improve the prevailing road safety situation.
- Full Text:
- Date Issued: 2015
Using agreements as an abstraction for access control administration
- Authors: Reyneke, André
- Date: 2007
- Subjects: Information -- control and access , Computer security -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9791 , http://hdl.handle.net/10948/598 , http://hdl.handle.net/10948/d1011701 , Information -- control and access , Computer security -- Management
- Description: The last couple of decades saw lots of changes in the business world. Not only did technology change at a rapid pace, but businesses' views with respect to the role that information plays also changed drastically. Information is now seen as a strategic resource. This change paved the way for the so-called knowledge worker that not only consumes information, but actively participates in creating new knowledge from information. Employees must therefore be empowered to fulfill their new role as knowledge workers. Empowerment happens through job redefinition and by ensuring that the appropriate information is at hand. Although information is more readily available to employees, appropriate access controls must still be implemented. However, there is conflict between the need to share information and the need to keep information confidential. These conflicting needs must be reflected in the administration of access control. In order to resolve these conflicts, a finer granularity of access controls must be implemented. However, to implement a finer granularity of access control, an increase in the number of access controls and, therefore, the administrative burden is inevitable. Access control administrators must cater for a potentially large number of systems. These systems can not only be heterogenous as far as architecture and technology are concerned, but also with respect to access control paradigms. Vendors have realized that human involvement must be minimized, giving birth to so-called "provisioning systems". Provisioning systems, in principle, automate certain parts of access control administration. However, currently implementations are done in an ad hoc manner, that is, without a systematic process of identifying the real access control needs. This study aims to address this problem by proposing the "agreement abstraction" as a possible vehicle for systematically analyzing the access control requirements in a business. In essence, the agreement abstraction allows us to identify opportunities where access control can be automated. A specific methodological approach is suggested whereby the business is analysed in terms of business processes, as opposed to the more traditional resource perspective. Various business processes are used as examples to explain and motivate the proposed agreement abstraction further. This dissertation therefore contributes to the field of discourse by presenting a new abstraction that can be used systematically to analyse access control administration requirements.
- Full Text:
- Date Issued: 2007
- Authors: Reyneke, André
- Date: 2007
- Subjects: Information -- control and access , Computer security -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9791 , http://hdl.handle.net/10948/598 , http://hdl.handle.net/10948/d1011701 , Information -- control and access , Computer security -- Management
- Description: The last couple of decades saw lots of changes in the business world. Not only did technology change at a rapid pace, but businesses' views with respect to the role that information plays also changed drastically. Information is now seen as a strategic resource. This change paved the way for the so-called knowledge worker that not only consumes information, but actively participates in creating new knowledge from information. Employees must therefore be empowered to fulfill their new role as knowledge workers. Empowerment happens through job redefinition and by ensuring that the appropriate information is at hand. Although information is more readily available to employees, appropriate access controls must still be implemented. However, there is conflict between the need to share information and the need to keep information confidential. These conflicting needs must be reflected in the administration of access control. In order to resolve these conflicts, a finer granularity of access controls must be implemented. However, to implement a finer granularity of access control, an increase in the number of access controls and, therefore, the administrative burden is inevitable. Access control administrators must cater for a potentially large number of systems. These systems can not only be heterogenous as far as architecture and technology are concerned, but also with respect to access control paradigms. Vendors have realized that human involvement must be minimized, giving birth to so-called "provisioning systems". Provisioning systems, in principle, automate certain parts of access control administration. However, currently implementations are done in an ad hoc manner, that is, without a systematic process of identifying the real access control needs. This study aims to address this problem by proposing the "agreement abstraction" as a possible vehicle for systematically analyzing the access control requirements in a business. In essence, the agreement abstraction allows us to identify opportunities where access control can be automated. A specific methodological approach is suggested whereby the business is analysed in terms of business processes, as opposed to the more traditional resource perspective. Various business processes are used as examples to explain and motivate the proposed agreement abstraction further. This dissertation therefore contributes to the field of discourse by presenting a new abstraction that can be used systematically to analyse access control administration requirements.
- Full Text:
- Date Issued: 2007
Users’ perceptions regarding password policies
- Authors: Fredericks, Damian Todd
- Date: 2018
- Subjects: Computers -- Access control , Computer networks -- Security measures Computer security
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/30205 , vital:30896
- Description: Information is considered a valuable asset to most organisations and is often exposed to various threats which exploit its confidentiality, integrity and availability (CIA). Identification and Authentication are commonly used to help ensure the CIA of information. This research study specifically focused on password-based authentication. Passwords are used to log into personal computers, company computers, email accounts, bank accounts and various software systems and mobile applications. Passwords act like a protective barrier between a user and their personal and company information, and remain the most cost-effective and most efficient method to control access to computer systems. An extensive content analysis was conducted regarding the security of passwords, as well as users’ password management coping strategies. It was determined that very little research has been conducted in relation to users’ perceptions towards password policies. The problem identified by this research is that organisations often implement password policy guidelines without taking into consideration users’ perceptions regarding such guidelines. This could result in users adopting various password management coping strategies. This research therefore aimed to determine users’ perceptions with regard to current password-related standards and best practices (password policy guidelines). Standards and best practices such as ISO/IEC 27002 (2013), NIST SP 800-118 (2009), NIST SP 800-63-2 (2013), NIST SP 800-63B (2016) and the SANS Password Protection Policy (2014b) were studied in order to determine the common elements of password policies. This research argued that before organisations implement password policy guidelines, they need to determine users’ perceptions towards such guidelines. It was identified that certain human factors such as human memory, attitude and apathy often cause users to adopt insecure coping strategies such as Reusing Passwords, Writing Down Passwords and Not Changing Passwords. This research included a survey which took the form of a questionnaire. The aim of the survey was to determine users’ perceptions towards common elements of password policies and to determine the coping strategies users commonly adopt. The survey included questions related to the new NIST SP 800-63B (2016) that sought to determine users’ perceptions towards these new NIST password policy iii guidelines. Findings from the survey indicated that respondents found the new NIST guidelines to be helpful, secure and easier to adhere to. Finally, recommendations regarding password policies were presented based on the common elements of password policies and users’ perceptions of the new NIST password guidelines. These recommendations could help policy makers in the implementation of new password policies or the revision of current password policies.
- Full Text:
- Date Issued: 2018
- Authors: Fredericks, Damian Todd
- Date: 2018
- Subjects: Computers -- Access control , Computer networks -- Security measures Computer security
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/30205 , vital:30896
- Description: Information is considered a valuable asset to most organisations and is often exposed to various threats which exploit its confidentiality, integrity and availability (CIA). Identification and Authentication are commonly used to help ensure the CIA of information. This research study specifically focused on password-based authentication. Passwords are used to log into personal computers, company computers, email accounts, bank accounts and various software systems and mobile applications. Passwords act like a protective barrier between a user and their personal and company information, and remain the most cost-effective and most efficient method to control access to computer systems. An extensive content analysis was conducted regarding the security of passwords, as well as users’ password management coping strategies. It was determined that very little research has been conducted in relation to users’ perceptions towards password policies. The problem identified by this research is that organisations often implement password policy guidelines without taking into consideration users’ perceptions regarding such guidelines. This could result in users adopting various password management coping strategies. This research therefore aimed to determine users’ perceptions with regard to current password-related standards and best practices (password policy guidelines). Standards and best practices such as ISO/IEC 27002 (2013), NIST SP 800-118 (2009), NIST SP 800-63-2 (2013), NIST SP 800-63B (2016) and the SANS Password Protection Policy (2014b) were studied in order to determine the common elements of password policies. This research argued that before organisations implement password policy guidelines, they need to determine users’ perceptions towards such guidelines. It was identified that certain human factors such as human memory, attitude and apathy often cause users to adopt insecure coping strategies such as Reusing Passwords, Writing Down Passwords and Not Changing Passwords. This research included a survey which took the form of a questionnaire. The aim of the survey was to determine users’ perceptions towards common elements of password policies and to determine the coping strategies users commonly adopt. The survey included questions related to the new NIST SP 800-63B (2016) that sought to determine users’ perceptions towards these new NIST password policy iii guidelines. Findings from the survey indicated that respondents found the new NIST guidelines to be helpful, secure and easier to adhere to. Finally, recommendations regarding password policies were presented based on the common elements of password policies and users’ perceptions of the new NIST password guidelines. These recommendations could help policy makers in the implementation of new password policies or the revision of current password policies.
- Full Text:
- Date Issued: 2018
User-interface evaluation metrics for a typical M-Learning application
- Authors: Kantore, Adelin
- Date: 2011
- Subjects: User interfaces (Computer systems) , Mobile communication systems
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9749 , http://hdl.handle.net/10948/1452 , User interfaces (Computer systems) , Mobile communication systems
- Description: Usability is seen as an important aspect for the quality of an M-learning application. Yet very little research has been conducted in this area – particularly in South Africa. Even though the trials of M-learning projects have been witnessed in the country during the last five years, very little is known about the systems that were implemented as regards their usability. Additionally, metrics and measures used in evaluating usability have not been reported. A need exists for relevant metrics to M-learning usability. The primary objective of this work was to propose metrics and measures – for the purpose of evaluating the User-Interfacedesign usability of M-learning application. The research included a literature review of M-learning, as well as the development of metrics and measures based on the Goal Question Metric (GQM) Model. This model has helped provide a reference model and measurements for evaluating the User-InterfaceUsability. A case study was used as a research strategy. An application called Kontax was selected for evaluation by users and expert reviewers. Data-collection methods consisted of User Testing and Heuristics evaluations. Data-gathering instruments included the use of surveys and user- satisfaction questionnaires based on the proposed metrics, task scenarios and expert-reviewed questionnaires based on the proposed metrics; all these instruments were developed. It was found that, although the users thought the system was very interesting, and they wished to hear more about it in the future, the system nevertheless had usability flaws which made it difficult to use. All the users failed to register so that they could use the system; additionally, the system-error messages did not help the users recognize, and recover from an error – leaving the user to simply log out. Help was not adequate, thus making it difficult for first-time users to know what to do when they needed support. The system was also said to have a lot of information presented on its home page, which caused the user to be disoriented. The Kontax application has usability flaws which should be III attended to, in order to improve its usability. The proposed metrics proved to be very useful in evaluating the usability of the tool.
- Full Text:
- Date Issued: 2011
- Authors: Kantore, Adelin
- Date: 2011
- Subjects: User interfaces (Computer systems) , Mobile communication systems
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9749 , http://hdl.handle.net/10948/1452 , User interfaces (Computer systems) , Mobile communication systems
- Description: Usability is seen as an important aspect for the quality of an M-learning application. Yet very little research has been conducted in this area – particularly in South Africa. Even though the trials of M-learning projects have been witnessed in the country during the last five years, very little is known about the systems that were implemented as regards their usability. Additionally, metrics and measures used in evaluating usability have not been reported. A need exists for relevant metrics to M-learning usability. The primary objective of this work was to propose metrics and measures – for the purpose of evaluating the User-Interfacedesign usability of M-learning application. The research included a literature review of M-learning, as well as the development of metrics and measures based on the Goal Question Metric (GQM) Model. This model has helped provide a reference model and measurements for evaluating the User-InterfaceUsability. A case study was used as a research strategy. An application called Kontax was selected for evaluation by users and expert reviewers. Data-collection methods consisted of User Testing and Heuristics evaluations. Data-gathering instruments included the use of surveys and user- satisfaction questionnaires based on the proposed metrics, task scenarios and expert-reviewed questionnaires based on the proposed metrics; all these instruments were developed. It was found that, although the users thought the system was very interesting, and they wished to hear more about it in the future, the system nevertheless had usability flaws which made it difficult to use. All the users failed to register so that they could use the system; additionally, the system-error messages did not help the users recognize, and recover from an error – leaving the user to simply log out. Help was not adequate, thus making it difficult for first-time users to know what to do when they needed support. The system was also said to have a lot of information presented on its home page, which caused the user to be disoriented. The Kontax application has usability flaws which should be III attended to, in order to improve its usability. The proposed metrics proved to be very useful in evaluating the usability of the tool.
- Full Text:
- Date Issued: 2011
User requirements framework for mobile government in the Western Cape
- Authors: Wilson, Fiona Michelle
- Date: 2013
- Subjects: Government communication systems , Internet in public administration , Electronic government information , Mobile communication systems , Information technology
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9751 , http://hdl.handle.net/10948/d1008076 , Government communication systems , Internet in public administration , Electronic government information , Mobile communication systems , Information technology
- Description: Globally, mobile technology use, particularly the use of mobile phones, is becoming increasingly widespread. One consequence of this growth is mounting interest in using mobile technologies in the public sector, particularly in developing countries, because it is seen as enabling better access to information and services for citizens. Mobile government (m-government), defined as the use of mobile technologies and applications for public sector services, promises to extend access to public services to marginalised sectors of the population and is emerging as a new focus in the ongoing challenge to provide efficient, effective and accessible public services. Though interest in m-government is emerging in the provincial Western Cape Government (WCG) of South Africa, few guidelines exist in the WCG to inform the development of public sector mobile services. This absence impacts on service delivery and the primary objective of this study was to propose a set of guidelines that could guide the prioritisation of citizen facing public sector services for mobile implementation in the Western Cape. The study considered two areas namely, government and user needs. The primary research question was to determine what public sector services citizens need and how these services should be prioritised for mobile delivery in the Western Cape. To address this, three research sub-questions were formulated. The first question aimed to examine conceptions of mobile government. To achieve this a literature study and documentation review was conducted, from which factors influencing service prioritisation emerged. The second research question aimed to identify citizen needs that could inform mobile public sector services in the Western Cape. Thus a survey and interviews were conducted with citizens using the WCG community ICT centres (e-Centres). The third research question aimed to identify factors that impact on the prioritisation of citizen facing public sectors for mobile delivery in the Western Cape. The findings from the literature study, survey and interviews conducted were used to address this research question. The results from the three research sub-questions were triangulated to address the main objective of the study and from this a set of guidelines for prioritising mobile public sector services in the Western Cape was proposed.
- Full Text:
- Date Issued: 2013
- Authors: Wilson, Fiona Michelle
- Date: 2013
- Subjects: Government communication systems , Internet in public administration , Electronic government information , Mobile communication systems , Information technology
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9751 , http://hdl.handle.net/10948/d1008076 , Government communication systems , Internet in public administration , Electronic government information , Mobile communication systems , Information technology
- Description: Globally, mobile technology use, particularly the use of mobile phones, is becoming increasingly widespread. One consequence of this growth is mounting interest in using mobile technologies in the public sector, particularly in developing countries, because it is seen as enabling better access to information and services for citizens. Mobile government (m-government), defined as the use of mobile technologies and applications for public sector services, promises to extend access to public services to marginalised sectors of the population and is emerging as a new focus in the ongoing challenge to provide efficient, effective and accessible public services. Though interest in m-government is emerging in the provincial Western Cape Government (WCG) of South Africa, few guidelines exist in the WCG to inform the development of public sector mobile services. This absence impacts on service delivery and the primary objective of this study was to propose a set of guidelines that could guide the prioritisation of citizen facing public sector services for mobile implementation in the Western Cape. The study considered two areas namely, government and user needs. The primary research question was to determine what public sector services citizens need and how these services should be prioritised for mobile delivery in the Western Cape. To address this, three research sub-questions were formulated. The first question aimed to examine conceptions of mobile government. To achieve this a literature study and documentation review was conducted, from which factors influencing service prioritisation emerged. The second research question aimed to identify citizen needs that could inform mobile public sector services in the Western Cape. Thus a survey and interviews were conducted with citizens using the WCG community ICT centres (e-Centres). The third research question aimed to identify factors that impact on the prioritisation of citizen facing public sectors for mobile delivery in the Western Cape. The findings from the literature study, survey and interviews conducted were used to address this research question. The results from the three research sub-questions were triangulated to address the main objective of the study and from this a set of guidelines for prioritising mobile public sector services in the Western Cape was proposed.
- Full Text:
- Date Issued: 2013
User experience metrics for Dr Math
- Authors: Ngaye, Zonke
- Date: 2012
- Subjects: Mathematics -- Data processing , Mathematical models , Mathematics -- Study and teaching , Numerical analysis
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9799 , http://hdl.handle.net/10948/d1012036 , Mathematics -- Data processing , Mathematical models , Mathematics -- Study and teaching , Numerical analysis
- Description: The purpose of this research study is to propose guidelines for providing a positive user experience for pupils using Dr Math®. User experience was found to have a positive impact on the acceptance and adoption of a product. Thus the proposed guidelines contribute in maximizing the adoption and acceptance of Dr Math® among pupils. This study begins with an introductory chapter that describes the problem that forms the basis for this research. The chapter defines the objectives that this study is intended to achieve in order to accomplish its ultimate goal. The methodology followed to conduct this research study as well as its scope are also defined here. The results from a preliminary survey revealed that despite its potential accessibility, Dr Math® has a low adoption rate. However, when compared to other mobile learning (m-learning) applications for mathematics learning, Dr Math® is more popular. Thus Dr Math® was selected as a case for study. Chapter 2 of this study provides a detailed description of Dr Math® as a local mobile application for mathematics learning. It was found that the affordability and accessibility of Dr Math® did not necessarily imply a high adoption rate. There are various possible barriers to its low adoption. User experience (UX), which is the focus of this study, is one of them. Thus, a subsequent chapter deals with UX. Chapter 3 discusses UX, its scope, components and definition and places particular emphasis on its significance in the success of any product. The chapter also highlights the characteristics of a positive UX and the importance of designing for this outcome. In Chapter 4, a discussion and justification of the methodology used to conduct this research is discussed. This study primarily employs a qualitative inductive approach within an interpretivism paradigm. An exploratory single case study was used to obtain an in-depth analysis of the case. Data was collected using Dr Math® log files as a documentary source. Gathered data was then analysed and organized into themes and categories using qualitative content analysis as outlined in Chapter 5. Also the findings obtained from the results, which are mainly the factors that were found to have an impact on the user interaction with Dr Math®, are presented here. The identified factors served as a basis from which the guidelines presented in Chapter 6 were developed. Chapter 7 presents the conclusions and recommendations of the research. From both theoretical and empirical work, it was concluded that Dr Math® has the potential to improve mathematics learning in South Africa. Its adoption rate, however, is not satisfying: hence, the investigation of the factors impacting on the user interaction with Dr Math®, from which the proposed guidelines are based.
- Full Text:
- Date Issued: 2012
- Authors: Ngaye, Zonke
- Date: 2012
- Subjects: Mathematics -- Data processing , Mathematical models , Mathematics -- Study and teaching , Numerical analysis
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9799 , http://hdl.handle.net/10948/d1012036 , Mathematics -- Data processing , Mathematical models , Mathematics -- Study and teaching , Numerical analysis
- Description: The purpose of this research study is to propose guidelines for providing a positive user experience for pupils using Dr Math®. User experience was found to have a positive impact on the acceptance and adoption of a product. Thus the proposed guidelines contribute in maximizing the adoption and acceptance of Dr Math® among pupils. This study begins with an introductory chapter that describes the problem that forms the basis for this research. The chapter defines the objectives that this study is intended to achieve in order to accomplish its ultimate goal. The methodology followed to conduct this research study as well as its scope are also defined here. The results from a preliminary survey revealed that despite its potential accessibility, Dr Math® has a low adoption rate. However, when compared to other mobile learning (m-learning) applications for mathematics learning, Dr Math® is more popular. Thus Dr Math® was selected as a case for study. Chapter 2 of this study provides a detailed description of Dr Math® as a local mobile application for mathematics learning. It was found that the affordability and accessibility of Dr Math® did not necessarily imply a high adoption rate. There are various possible barriers to its low adoption. User experience (UX), which is the focus of this study, is one of them. Thus, a subsequent chapter deals with UX. Chapter 3 discusses UX, its scope, components and definition and places particular emphasis on its significance in the success of any product. The chapter also highlights the characteristics of a positive UX and the importance of designing for this outcome. In Chapter 4, a discussion and justification of the methodology used to conduct this research is discussed. This study primarily employs a qualitative inductive approach within an interpretivism paradigm. An exploratory single case study was used to obtain an in-depth analysis of the case. Data was collected using Dr Math® log files as a documentary source. Gathered data was then analysed and organized into themes and categories using qualitative content analysis as outlined in Chapter 5. Also the findings obtained from the results, which are mainly the factors that were found to have an impact on the user interaction with Dr Math®, are presented here. The identified factors served as a basis from which the guidelines presented in Chapter 6 were developed. Chapter 7 presents the conclusions and recommendations of the research. From both theoretical and empirical work, it was concluded that Dr Math® has the potential to improve mathematics learning in South Africa. Its adoption rate, however, is not satisfying: hence, the investigation of the factors impacting on the user interaction with Dr Math®, from which the proposed guidelines are based.
- Full Text:
- Date Issued: 2012
User experience guidelines for mobile natural user interfaces: a case study of physically disabled users
- Authors: Jacobs, Gershwin
- Date: 2017
- Subjects: User interfaces (Computer systems) Human-computer interaction , Mobile computing Augmented reality
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/17547 , vital:28377
- Description: Motor impaired people are faced with many challenges, one being the of lack integration into certain spheres of society. Access to information is seen as a major issue for the motor impaired since most forms of interaction or interactive devices are not suited to the needs of motor impaired people. People with motor impairments, like the rest of the population, are increasingly using mobile phones. As a result of the current devices and methods used for interaction with content on mobile phones, various factors prohibit a pleasant experience for users with motor impairments. To counter these factors, this study recognizes the need to implement better suited methods of interaction and navigation to improve accessibility, usability and user experience for motor impaired users. The objective of the study was to gain an understanding of the nature of motor impairments and the challenges that this group of people face when using mobile phones. Once this was determined, a solution to address this problem was found in the form of natural user interfaces. In order to gain a better understanding of this technology, various forms of NUIs and the benefits thereof were studied by the researcher in order to determine how this technology can be implemented to meet the needs of motor impaired people. To test theory, the Samsung Galaxy s5 was selected as the NUI device for the study. It must be noted that this study started in the year 2013 and the Galaxy S5 was the latest device claiming to improve interaction for disabled people at the time. This device was used in a case study that made use of various data collection methods, including participant interviews. Various motor impaired participants were requested to perform predefined tasks on the device, along with the completion of a set of user experience questionnaires. Based on the results of the study, it was found that interaction with mobile phones is an issue for people with motor impairments and that alternative methods of interaction need to be implemented. These results contributed to the final output of this study, namely a set of user experience guidelines for the design of mobile human computer interaction for motor impaired users.
- Full Text:
- Date Issued: 2017
- Authors: Jacobs, Gershwin
- Date: 2017
- Subjects: User interfaces (Computer systems) Human-computer interaction , Mobile computing Augmented reality
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/17547 , vital:28377
- Description: Motor impaired people are faced with many challenges, one being the of lack integration into certain spheres of society. Access to information is seen as a major issue for the motor impaired since most forms of interaction or interactive devices are not suited to the needs of motor impaired people. People with motor impairments, like the rest of the population, are increasingly using mobile phones. As a result of the current devices and methods used for interaction with content on mobile phones, various factors prohibit a pleasant experience for users with motor impairments. To counter these factors, this study recognizes the need to implement better suited methods of interaction and navigation to improve accessibility, usability and user experience for motor impaired users. The objective of the study was to gain an understanding of the nature of motor impairments and the challenges that this group of people face when using mobile phones. Once this was determined, a solution to address this problem was found in the form of natural user interfaces. In order to gain a better understanding of this technology, various forms of NUIs and the benefits thereof were studied by the researcher in order to determine how this technology can be implemented to meet the needs of motor impaired people. To test theory, the Samsung Galaxy s5 was selected as the NUI device for the study. It must be noted that this study started in the year 2013 and the Galaxy S5 was the latest device claiming to improve interaction for disabled people at the time. This device was used in a case study that made use of various data collection methods, including participant interviews. Various motor impaired participants were requested to perform predefined tasks on the device, along with the completion of a set of user experience questionnaires. Based on the results of the study, it was found that interaction with mobile phones is an issue for people with motor impairments and that alternative methods of interaction need to be implemented. These results contributed to the final output of this study, namely a set of user experience guidelines for the design of mobile human computer interaction for motor impaired users.
- Full Text:
- Date Issued: 2017
Use of recycled rubber tyres as an alternative ingredient in cementitious building materials
- Authors: Yuill, Robert Mark
- Date: 2018
- Subjects: Building materials , Building materials -- Environmental aspects Sustainable construction Recycled products
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/29783 , vital:30777
- Description: The need to incorporate recycled materials in building products is becoming more important than ever before. There is an abundance of waste rubber tyres which in turn results in a waste management issue. The use of waste rubber tyres in cementitious building material provides a possible solution to the problem (Kathomi, 2009:10). Previous research has shown the introduction of recycled rubber tyre crumb can improve the durability, thermal and acoustic performance in residential and commercial buildings. This could result in lives of dwellers in concrete block buildings in South Africa improving due to these characteristics whilst potentially creating a cost-effective, sustainable building material. A grading analysis, loose and compacted bulk densities and relative densities were determined to provide a mix design. Three tests were conducted for this study namely compressive strength, fire and thermal performance and acoustic performance. The testing was conducted on 100mmx100mm cubes at varying rubber replacement percentages. The replacement values were 10%, 20% and 30% tested against a control of ordinary concrete. The waste rubber crumb was a replacement for sand. The research of this study showed 20 % decrease of compression strength at 10 % rubber replacement compared to the control, 55 % decrease at 20 % rubber replacement and 75% decrease at 30 % rubber replacement. The thermal performance test showed a 24 % lower temperature for 10 % rubber replacement compared to the control, 39 % lower temperature at 20 % rubber replacement and 52 % lower temperature at 30 % rubber replacement. All rubber replacement % samples and the control performed adequately in the flame resistance test. The smoke density test showed that all rubber replacement % samples did not release a quantity of smoke which would be deemed dangerous. The acoustic performance test showed the values at 10% rubber replacement was 6 % lower; at 20% rubber replacement; 4% lower and at 30% rubber replacement 14 % lower. Based on these results, the acoustic performance regarding transmission increases with a rubber replacement % higher than 20 %.
- Full Text:
- Date Issued: 2018
- Authors: Yuill, Robert Mark
- Date: 2018
- Subjects: Building materials , Building materials -- Environmental aspects Sustainable construction Recycled products
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/29783 , vital:30777
- Description: The need to incorporate recycled materials in building products is becoming more important than ever before. There is an abundance of waste rubber tyres which in turn results in a waste management issue. The use of waste rubber tyres in cementitious building material provides a possible solution to the problem (Kathomi, 2009:10). Previous research has shown the introduction of recycled rubber tyre crumb can improve the durability, thermal and acoustic performance in residential and commercial buildings. This could result in lives of dwellers in concrete block buildings in South Africa improving due to these characteristics whilst potentially creating a cost-effective, sustainable building material. A grading analysis, loose and compacted bulk densities and relative densities were determined to provide a mix design. Three tests were conducted for this study namely compressive strength, fire and thermal performance and acoustic performance. The testing was conducted on 100mmx100mm cubes at varying rubber replacement percentages. The replacement values were 10%, 20% and 30% tested against a control of ordinary concrete. The waste rubber crumb was a replacement for sand. The research of this study showed 20 % decrease of compression strength at 10 % rubber replacement compared to the control, 55 % decrease at 20 % rubber replacement and 75% decrease at 30 % rubber replacement. The thermal performance test showed a 24 % lower temperature for 10 % rubber replacement compared to the control, 39 % lower temperature at 20 % rubber replacement and 52 % lower temperature at 30 % rubber replacement. All rubber replacement % samples and the control performed adequately in the flame resistance test. The smoke density test showed that all rubber replacement % samples did not release a quantity of smoke which would be deemed dangerous. The acoustic performance test showed the values at 10% rubber replacement was 6 % lower; at 20% rubber replacement; 4% lower and at 30% rubber replacement 14 % lower. Based on these results, the acoustic performance regarding transmission increases with a rubber replacement % higher than 20 %.
- Full Text:
- Date Issued: 2018
Urban resilience determinants with specific reference to the Buffalo City Metropolitan Municipality, East London
- Authors: Ntakana, Khululekani
- Date: 2017
- Subjects: City planning -- South Africa -- East London Sustainable development -- South Africa -- East London , Regional planning -- South Africa -- East London Infrastructure (Economics) -- South Africa -- East London -- Planning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/19495 , vital:28886
- Description: The year 1994 marked the dawn of the new democratic South Africa, bringing its own set of challenges to the country. Currently urban areas cover only one and a half percent of South Africa’s surface area. However, sixty one percent of South Africans live in urban areas. Furthermore, the average growth rate for urban areas has been consistently higher than the population growth rate during the period from 1998 to 2008. This resulted in larger towns and cities, growing at the expense of rural areas, with metropolitan areas experiencing the highest influx, followed by secondary cities. However, urban areas consume more water, food, energy, and durable goods, and have an impact far beyond the urban boundaries. This directly relates to urban decline. The rapid influx of people into urban areas that are already overcrowded with large service delivery backlogs, has led to the formation of informal settlements in exposed locations. Many of the informal dwellings in South Africa are subjected to environmental factors. The absence of basic services in overcrowded areas is linked to negative health outcomes and enhanced environmental degradation. This study is a critical review of a phenomenon named urban resilience. The report seeks to highlight the current status in cities and the transformation that cities need to undergo to enable them to become the cities of tomorrow. Indeed, “sustainable future cities and human settlements begin today”. The paper raises arguments on urban resilience by different theorists, philosophers, academics and scholars. The study proceeds to unpack the urban resilience determinants. Furthermore, the challenges cites will experience in responding to rapid urbanisation and their denial attitude to informal settlement and environmental degradation, which include how cities respond to climate change, are under investigation . The purpose of the study is to share the theoretical framework relative to the urban resilience determinants, with the intention to solicit criticism on gaps and blind spots. This is done with specific reference to Buffalo City Municipality. This study aims to contribute to the goals of municipalities by improving understanding of the drivers of urban resilience. This will, in turn, enable a city system to withstand and recover quickly from multiple and diverse shocks and stresses, and improve its performance over time. However, this study was conducted within a qualitative paradigm. The study followed a non-probability sampling technique. Categories of data sources were identified based on their probability to hold information that is crucial to the study. For each category, this study followed a 50 + 1 rule for sampling size when the population of the data sources were identified and access gained. he statistical software (SPSS) supported by a qualified statistician was used to analyse data qualitatively in attempt to answer the research question.
- Full Text:
- Date Issued: 2017
- Authors: Ntakana, Khululekani
- Date: 2017
- Subjects: City planning -- South Africa -- East London Sustainable development -- South Africa -- East London , Regional planning -- South Africa -- East London Infrastructure (Economics) -- South Africa -- East London -- Planning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/19495 , vital:28886
- Description: The year 1994 marked the dawn of the new democratic South Africa, bringing its own set of challenges to the country. Currently urban areas cover only one and a half percent of South Africa’s surface area. However, sixty one percent of South Africans live in urban areas. Furthermore, the average growth rate for urban areas has been consistently higher than the population growth rate during the period from 1998 to 2008. This resulted in larger towns and cities, growing at the expense of rural areas, with metropolitan areas experiencing the highest influx, followed by secondary cities. However, urban areas consume more water, food, energy, and durable goods, and have an impact far beyond the urban boundaries. This directly relates to urban decline. The rapid influx of people into urban areas that are already overcrowded with large service delivery backlogs, has led to the formation of informal settlements in exposed locations. Many of the informal dwellings in South Africa are subjected to environmental factors. The absence of basic services in overcrowded areas is linked to negative health outcomes and enhanced environmental degradation. This study is a critical review of a phenomenon named urban resilience. The report seeks to highlight the current status in cities and the transformation that cities need to undergo to enable them to become the cities of tomorrow. Indeed, “sustainable future cities and human settlements begin today”. The paper raises arguments on urban resilience by different theorists, philosophers, academics and scholars. The study proceeds to unpack the urban resilience determinants. Furthermore, the challenges cites will experience in responding to rapid urbanisation and their denial attitude to informal settlement and environmental degradation, which include how cities respond to climate change, are under investigation . The purpose of the study is to share the theoretical framework relative to the urban resilience determinants, with the intention to solicit criticism on gaps and blind spots. This is done with specific reference to Buffalo City Municipality. This study aims to contribute to the goals of municipalities by improving understanding of the drivers of urban resilience. This will, in turn, enable a city system to withstand and recover quickly from multiple and diverse shocks and stresses, and improve its performance over time. However, this study was conducted within a qualitative paradigm. The study followed a non-probability sampling technique. Categories of data sources were identified based on their probability to hold information that is crucial to the study. For each category, this study followed a 50 + 1 rule for sampling size when the population of the data sources were identified and access gained. he statistical software (SPSS) supported by a qualified statistician was used to analyse data qualitatively in attempt to answer the research question.
- Full Text:
- Date Issued: 2017
Unlocking the development of built environment professionals through infrastructure investment in South Africa
- Authors: Mputa, Nobutyani Sinethemba
- Date: 2013
- Subjects: Career development -- South Africa , Construction workers -- South Africa , Infrastructure (Economics) -- South Africa , Job security -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9673 , http://hdl.handle.net/10948/d1020049
- Description: spending is regarded to be one of the major contributors to economic growth. The purpose of the study was to investigate how infrastructure projects could engender professional skills development. The topic is focused on a human resource (HR) perspective as it is one of the knowledge areas in project management. In order to achieve the research objectives and also establish the breadth of the subject issues in the literature review, a qualitative methodology was employed. Interviews were conducted and the majority of the participants were working towards professional registration in the built environment professions. The empirical findings that emerged from the study show that the majority of the respondents agreed that HR units should be aware of the legislation related to professional training and education. The interviewees further elucidate that, although professional registration is the primary duty of the candidate, HR units should ensure that interns are doing what is in line with their professional requirements, according to different councils, to ensure compliance. However, the lack of a structured approach in administering training programmes is a key factor that contributes to the lack of development of professional skills on government sponsored infrastructure projects. This must be addressed to attain the desired professional development outcomes among historically disadvantaged individuals (HDIs) that are keen on professional registration and development in the built environment professions. Other empirical findings showed that most of the respondents showed some concern regarding job security with their present employment. They explained that once the status of professional registration is attained, securing employment in the industry should be relatively easy. South Africa needs a highly skilled workforce to ensure growth of the economy therefore HR departments in organisation should adapt a systematic approach in their HR planning in order to ensure skills are engendered to HDIs as well.
- Full Text:
- Date Issued: 2013
- Authors: Mputa, Nobutyani Sinethemba
- Date: 2013
- Subjects: Career development -- South Africa , Construction workers -- South Africa , Infrastructure (Economics) -- South Africa , Job security -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9673 , http://hdl.handle.net/10948/d1020049
- Description: spending is regarded to be one of the major contributors to economic growth. The purpose of the study was to investigate how infrastructure projects could engender professional skills development. The topic is focused on a human resource (HR) perspective as it is one of the knowledge areas in project management. In order to achieve the research objectives and also establish the breadth of the subject issues in the literature review, a qualitative methodology was employed. Interviews were conducted and the majority of the participants were working towards professional registration in the built environment professions. The empirical findings that emerged from the study show that the majority of the respondents agreed that HR units should be aware of the legislation related to professional training and education. The interviewees further elucidate that, although professional registration is the primary duty of the candidate, HR units should ensure that interns are doing what is in line with their professional requirements, according to different councils, to ensure compliance. However, the lack of a structured approach in administering training programmes is a key factor that contributes to the lack of development of professional skills on government sponsored infrastructure projects. This must be addressed to attain the desired professional development outcomes among historically disadvantaged individuals (HDIs) that are keen on professional registration and development in the built environment professions. Other empirical findings showed that most of the respondents showed some concern regarding job security with their present employment. They explained that once the status of professional registration is attained, securing employment in the industry should be relatively easy. South Africa needs a highly skilled workforce to ensure growth of the economy therefore HR departments in organisation should adapt a systematic approach in their HR planning in order to ensure skills are engendered to HDIs as well.
- Full Text:
- Date Issued: 2013
Understanding factors that influence the acceptance of electronic medical records by nurses in hospitals: a framework
- Authors: Makalima, Melissa
- Date: 2018
- Subjects: Electronic records -- Management , Information storage and retrieval systems -- Management Medical records -- South Africa Medical records -- Data processing
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/31488 , vital:31495
- Description: Globally, unlike in the past, it is rare for a patient to consult the same healthcare provider throughout his or her lifetime. However, this makes it difficult to maintain informational continuity of care. Researchers have confirmed that paper-based methods of record keeping do not meet the needs of informational continuity of care. As a result, the popularity of electronic means of recordkeeping, specifically, electronic medical records (EMRs), is growing. However, the implementation of EMRs in hospitals is not without challenges with these challenges playing a significant role in the failure of EMRs. One such challenge is a lack of user acceptance. Research reveals that nurses comprise the largest user group of EMRs in the hospital setting. However, there is inadequate literature that focuses on the factors contributing to EMR acceptance with nurses as the user group. Hence, the main problem addressed in this research study relates to the inadequate understanding of the factors that influence the acceptance of EMRs by nurses. In order to address this problem, a literature review and a case study were conducted to ascertain and investigate the factors that influence the acceptance of EMRs by nurses. A total of 39 factors were formulated. Subsequent to the formulation of these factors, knowledge on the impact of each factor on EMR acceptance was collected. Socio-technical Systems Theory (STS) was used as a theoretical lens through which to view the resulting factors. The STS dimension from which each factor originates as well as the STS dimension influenced by the factor were identified. The analysis of the different stages of acceptance as well as the STS analysis resulted in a framework that could play an important role in providing a better understanding of EMR acceptance by nurses in hospitals. It was anticipated that this study would contribute to a better understanding of the factors that hospitals should address in order to create a conducive environment for EMR acceptance by nurses within the hospitals.
- Full Text:
- Date Issued: 2018
- Authors: Makalima, Melissa
- Date: 2018
- Subjects: Electronic records -- Management , Information storage and retrieval systems -- Management Medical records -- South Africa Medical records -- Data processing
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/31488 , vital:31495
- Description: Globally, unlike in the past, it is rare for a patient to consult the same healthcare provider throughout his or her lifetime. However, this makes it difficult to maintain informational continuity of care. Researchers have confirmed that paper-based methods of record keeping do not meet the needs of informational continuity of care. As a result, the popularity of electronic means of recordkeeping, specifically, electronic medical records (EMRs), is growing. However, the implementation of EMRs in hospitals is not without challenges with these challenges playing a significant role in the failure of EMRs. One such challenge is a lack of user acceptance. Research reveals that nurses comprise the largest user group of EMRs in the hospital setting. However, there is inadequate literature that focuses on the factors contributing to EMR acceptance with nurses as the user group. Hence, the main problem addressed in this research study relates to the inadequate understanding of the factors that influence the acceptance of EMRs by nurses. In order to address this problem, a literature review and a case study were conducted to ascertain and investigate the factors that influence the acceptance of EMRs by nurses. A total of 39 factors were formulated. Subsequent to the formulation of these factors, knowledge on the impact of each factor on EMR acceptance was collected. Socio-technical Systems Theory (STS) was used as a theoretical lens through which to view the resulting factors. The STS dimension from which each factor originates as well as the STS dimension influenced by the factor were identified. The analysis of the different stages of acceptance as well as the STS analysis resulted in a framework that could play an important role in providing a better understanding of EMR acceptance by nurses in hospitals. It was anticipated that this study would contribute to a better understanding of the factors that hospitals should address in order to create a conducive environment for EMR acceptance by nurses within the hospitals.
- Full Text:
- Date Issued: 2018
Ultra-high precision manufacturing
- Authors: Abou-El-Hossein, Khaled
- Subjects: Machining , Diamond turning , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20878 , vital:29410
- Description: One of the engineering areas focusing on the research and development of highvalue components and manufacturing technologies is precision engineering. Precision engineering represents a variety of engineering and science disciplines ranging from areas such as mechanical, electronics and industrial engineering to chemistry, physics, optics and materials science. This paper aims at familiarising the reader with the recent advances in ultra-high precision manufacturing technologies and their applications for the production of various critical components employed in different sectors of the industry. In this paper, the principles of ultra-high precision manufacturing will be discussed followed by examples of its use in various industrial applications. The status of ultra-high precision manufacturing in terms of current research issues and future trends will be discussed. In addition, research activities and projects in the area of precision manufacturing that are currently conducted at the NMMU will be also highlighted. Finally, the author looks forward to presenting herewith comprehensive information that could be useful to the reader and easy to understand by the bigger NMMU’s community.
- Full Text:
- Authors: Abou-El-Hossein, Khaled
- Subjects: Machining , Diamond turning , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20878 , vital:29410
- Description: One of the engineering areas focusing on the research and development of highvalue components and manufacturing technologies is precision engineering. Precision engineering represents a variety of engineering and science disciplines ranging from areas such as mechanical, electronics and industrial engineering to chemistry, physics, optics and materials science. This paper aims at familiarising the reader with the recent advances in ultra-high precision manufacturing technologies and their applications for the production of various critical components employed in different sectors of the industry. In this paper, the principles of ultra-high precision manufacturing will be discussed followed by examples of its use in various industrial applications. The status of ultra-high precision manufacturing in terms of current research issues and future trends will be discussed. In addition, research activities and projects in the area of precision manufacturing that are currently conducted at the NMMU will be also highlighted. Finally, the author looks forward to presenting herewith comprehensive information that could be useful to the reader and easy to understand by the bigger NMMU’s community.
- Full Text:
Ultra-high precision machining of rapidly solidified aluminium (RSA) alloys for optics
- Authors: Odedeyi, Peter Babatunde
- Date: 2021-12
- Subjects: Mechatronics Surface roughness -- Measurement
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55921 , vital:54400
- Description: The advancement of ultra-precision is one of the most adaptable machining processes in the manufacturing of very complex and high-quality surface structures for optics, industrial, medical, aerospace and communication applications. Studies have shown that single-point diamond turning has an outstanding ability to machine high-quality optical components at a nanometric scale. However, in a responsive cutting process, the nanometric machinability of these optical components can easily be affected by several factors. The call for increasing needs of optical systems has recently led to the development of newly modified aluminium grades of non-ferrous alloys characterized by finer microstructures, defined mechanical and physical properties. To date, there has been a lack of sufficient research into these new aluminium alloys. In modern ultra-precision machining, the high demands for smart and inexpensive cutting tools are becoming more relevant in recent precision machines. In monitoring and predicting high-quality surface, cutting forces in single point diamond turning are believed to be as critical as other machining processes due to their potential effects on the quality of surface roughness. Undermining such an important factor is a compromise between the machining process's efficiency and the increased cost of production. Therefore, a comprehensive scientific understanding of the Nano-cutting mechanics is critical, particularly on modelling and analysis of cutting force, surface roughness, chip vii formation, acoustic emission, material removal rates, and molecular dynamic simulation of the rapidly solidified aluminium alloys to bridge the gap between fundamentals and industrial-scale application. The study is divided into three essential sections. First, the development of a force sensor. Secondly, investigation of the effect of cutting parameters (i.e., cutting speed, feed rate, and cutting depth) on cutting force, acoustic emission (AE), material removal rate (MRR), chip formation, Nose radius, and surface roughness (Ra), which play a leading role in the determination of machine productivity and efficiency of single-point diamond turning of rapidly solidified aluminium alloys. Thirdly, a 3-D molecular dynamic (MD) simulation of RSA 6061 is also carried out to further understand the nanometric mechanism and characterization of the alloy. The experiment was mainly conducted using Precitech Nanoform ultra-grind 250 lathe machines on three different advanced optical aluminium alloys materials; these are RSA 443, RSA 905, and RSA 6061. , Thesis (PhD) -- Faculty of Engineering, the Built Environment and Information Technology, School of Engineering, 2021
- Full Text:
- Date Issued: 2021-12
- Authors: Odedeyi, Peter Babatunde
- Date: 2021-12
- Subjects: Mechatronics Surface roughness -- Measurement
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55921 , vital:54400
- Description: The advancement of ultra-precision is one of the most adaptable machining processes in the manufacturing of very complex and high-quality surface structures for optics, industrial, medical, aerospace and communication applications. Studies have shown that single-point diamond turning has an outstanding ability to machine high-quality optical components at a nanometric scale. However, in a responsive cutting process, the nanometric machinability of these optical components can easily be affected by several factors. The call for increasing needs of optical systems has recently led to the development of newly modified aluminium grades of non-ferrous alloys characterized by finer microstructures, defined mechanical and physical properties. To date, there has been a lack of sufficient research into these new aluminium alloys. In modern ultra-precision machining, the high demands for smart and inexpensive cutting tools are becoming more relevant in recent precision machines. In monitoring and predicting high-quality surface, cutting forces in single point diamond turning are believed to be as critical as other machining processes due to their potential effects on the quality of surface roughness. Undermining such an important factor is a compromise between the machining process's efficiency and the increased cost of production. Therefore, a comprehensive scientific understanding of the Nano-cutting mechanics is critical, particularly on modelling and analysis of cutting force, surface roughness, chip vii formation, acoustic emission, material removal rates, and molecular dynamic simulation of the rapidly solidified aluminium alloys to bridge the gap between fundamentals and industrial-scale application. The study is divided into three essential sections. First, the development of a force sensor. Secondly, investigation of the effect of cutting parameters (i.e., cutting speed, feed rate, and cutting depth) on cutting force, acoustic emission (AE), material removal rate (MRR), chip formation, Nose radius, and surface roughness (Ra), which play a leading role in the determination of machine productivity and efficiency of single-point diamond turning of rapidly solidified aluminium alloys. Thirdly, a 3-D molecular dynamic (MD) simulation of RSA 6061 is also carried out to further understand the nanometric mechanism and characterization of the alloy. The experiment was mainly conducted using Precitech Nanoform ultra-grind 250 lathe machines on three different advanced optical aluminium alloys materials; these are RSA 443, RSA 905, and RSA 6061. , Thesis (PhD) -- Faculty of Engineering, the Built Environment and Information Technology, School of Engineering, 2021
- Full Text:
- Date Issued: 2021-12
Ultra-high precision machining of contact lens polymers
- Authors: Olufayo, Oluwole Ayodeji
- Date: 2015
- Subjects: Contact lenses , Polymers
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/3001 , vital:20385
- Description: Contact lens manufacture requires a high level of accuracy and surface integrity in the range of a few nanometres. Amidst numerous optical manufacturing techniques, single-point diamond turning is widely employed in the making of contact lenses due to its capability of producing optical surfaces of complex shapes and nanometric accuracy. For process optimisation, it is ideal to assess the effects of various conditions and also establish their relationships with the surface finish. Presently, there is little information available on the performance of single point diamond turning when machining contact lens polymers. Therefore, the research work undertaken herewith is aimed at testing known facts in contact lens diamond turning and investigating the performance of ultra-high precision manufacturing of contact lens polymers. Experimental tests were conducted on Roflufocon E, which is a commercially available contact lens polymer and on Precitech Nanoform Ultra-grind 250 precision machining. Tests were performed at varying cutting feeds, speed and depth of cut. Initial experimental tests investigated the influence of process factors affecting surface finish in the UHPM of lenses. The acquired data were statistically analysed using Response Surface Method (RSM) to create a model of the process. Subsequently, a model which uses Runge-Kutta’s fourth order non-linear finite series scheme was developed and adapted to deduce the force occurring at the tool tip. These forces were also statistically analysed and modelled to also predict the effects process factors have on cutting force. Further experimental tests were aimed at establishing the presence of the triboelectric wear phenomena occurring during polymer machining and identifying the most influential process factors. Results indicate that feed rate is a significant factor in the generation of high optical surface quality. In addition, the depth of cut was identified as a significant factor in the generation of low surface roughness in lenses. The influence some of these process factors had was notably linked to triboelectric effects. This tribological effect was generated from the continuous rubbing action of magnetised chips on the cutting tool. This further stresses the presence of high static charging during cutting. Moderately humid cutting conditions presented an adequate means for static charge control and displayed improved surface finishes. In all experimental tests, the feed rate was identified as the most significant factor within the range of cutting parameters employed. Hence, the results validated the fact that feed rate had a high influence in polymer machining. The work also established the relationship on how surface roughness of an optical lens responded to monitoring signals and parameters such as force, feed, speed and depth of cut during machining and it generated models for prediction of surface finishes and appropriate selection of parameters. Furthermore, the study provides a molecular simulation analysis for validating observed conditions occurring at the nanometric scale in polymer machining. This is novel in molecular polymer modelling. The outcome of this research has contributed significantly to the body of knowledge and has provided basic information in the area of precision manufacturing of optical components of high surface integrity such as contact lenses. The application of the research findings presented here cuts across various fields such as medicine, semi-conductors, aerospace, defence, telecom, lasers, instrumentation and life sciences.
- Full Text:
- Date Issued: 2015
- Authors: Olufayo, Oluwole Ayodeji
- Date: 2015
- Subjects: Contact lenses , Polymers
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/3001 , vital:20385
- Description: Contact lens manufacture requires a high level of accuracy and surface integrity in the range of a few nanometres. Amidst numerous optical manufacturing techniques, single-point diamond turning is widely employed in the making of contact lenses due to its capability of producing optical surfaces of complex shapes and nanometric accuracy. For process optimisation, it is ideal to assess the effects of various conditions and also establish their relationships with the surface finish. Presently, there is little information available on the performance of single point diamond turning when machining contact lens polymers. Therefore, the research work undertaken herewith is aimed at testing known facts in contact lens diamond turning and investigating the performance of ultra-high precision manufacturing of contact lens polymers. Experimental tests were conducted on Roflufocon E, which is a commercially available contact lens polymer and on Precitech Nanoform Ultra-grind 250 precision machining. Tests were performed at varying cutting feeds, speed and depth of cut. Initial experimental tests investigated the influence of process factors affecting surface finish in the UHPM of lenses. The acquired data were statistically analysed using Response Surface Method (RSM) to create a model of the process. Subsequently, a model which uses Runge-Kutta’s fourth order non-linear finite series scheme was developed and adapted to deduce the force occurring at the tool tip. These forces were also statistically analysed and modelled to also predict the effects process factors have on cutting force. Further experimental tests were aimed at establishing the presence of the triboelectric wear phenomena occurring during polymer machining and identifying the most influential process factors. Results indicate that feed rate is a significant factor in the generation of high optical surface quality. In addition, the depth of cut was identified as a significant factor in the generation of low surface roughness in lenses. The influence some of these process factors had was notably linked to triboelectric effects. This tribological effect was generated from the continuous rubbing action of magnetised chips on the cutting tool. This further stresses the presence of high static charging during cutting. Moderately humid cutting conditions presented an adequate means for static charge control and displayed improved surface finishes. In all experimental tests, the feed rate was identified as the most significant factor within the range of cutting parameters employed. Hence, the results validated the fact that feed rate had a high influence in polymer machining. The work also established the relationship on how surface roughness of an optical lens responded to monitoring signals and parameters such as force, feed, speed and depth of cut during machining and it generated models for prediction of surface finishes and appropriate selection of parameters. Furthermore, the study provides a molecular simulation analysis for validating observed conditions occurring at the nanometric scale in polymer machining. This is novel in molecular polymer modelling. The outcome of this research has contributed significantly to the body of knowledge and has provided basic information in the area of precision manufacturing of optical components of high surface integrity such as contact lenses. The application of the research findings presented here cuts across various fields such as medicine, semi-conductors, aerospace, defence, telecom, lasers, instrumentation and life sciences.
- Full Text:
- Date Issued: 2015
Ultra-high precision grinding of BK7 glass
- Authors: Onwuka, Goodness Raluchukwu
- Date: 2016
- Subjects: Machining , Machine-tools -- Monitoring , Acoustic emission
- Language: English
- Type: Thesis , Masters , MEngineering
- Identifier: http://hdl.handle.net/10948/5203 , vital:20820
- Description: With the increase in the application of ultra-precision manufactured parts and the absence of much participation of researchers in ultra-high precision grinding of optical glasses which has a high rate of demand in the industries, it becomes imperative to garner a full understanding of the production of these precision optics using the above-listed technology. Single point inclined axes grinding configuration and Box-Behnken experimental design was developed and applied to the ultra-high precision grinding of BK7 glass. A high sampling acoustic emission monitoring system was implemented to monitor the process. The research tends to monitor the ultra-high precision grinding of BK7 glass using acoustic emission which has proven to be an effective sensing technique to monitor grinding processes. Response surface methodology was adopted to analyze the effect of the interaction between the machining parameters: feed, speed, depth of cut and the generated surface roughness. Furthermore, back propagation Artificial Neural Network was also implemented through careful feature extraction and selection process. The proposed models are aimed at creating a database guide to the ultra-high precision grinding of precision optics.
- Full Text:
- Date Issued: 2016
- Authors: Onwuka, Goodness Raluchukwu
- Date: 2016
- Subjects: Machining , Machine-tools -- Monitoring , Acoustic emission
- Language: English
- Type: Thesis , Masters , MEngineering
- Identifier: http://hdl.handle.net/10948/5203 , vital:20820
- Description: With the increase in the application of ultra-precision manufactured parts and the absence of much participation of researchers in ultra-high precision grinding of optical glasses which has a high rate of demand in the industries, it becomes imperative to garner a full understanding of the production of these precision optics using the above-listed technology. Single point inclined axes grinding configuration and Box-Behnken experimental design was developed and applied to the ultra-high precision grinding of BK7 glass. A high sampling acoustic emission monitoring system was implemented to monitor the process. The research tends to monitor the ultra-high precision grinding of BK7 glass using acoustic emission which has proven to be an effective sensing technique to monitor grinding processes. Response surface methodology was adopted to analyze the effect of the interaction between the machining parameters: feed, speed, depth of cut and the generated surface roughness. Furthermore, back propagation Artificial Neural Network was also implemented through careful feature extraction and selection process. The proposed models are aimed at creating a database guide to the ultra-high precision grinding of precision optics.
- Full Text:
- Date Issued: 2016