A customer service strategy for Ngqura Container Terminal
- Mtshiselwa, Mkhululi Terrence
- Authors: Mtshiselwa, Mkhululi Terrence
- Date: 2014
- Subjects: SERVQUAL (Service quality framework) , Customer services -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/8955 , vital:26446
- Description: The container terminals play an increasingly important role in the economy of many countries. In today’s global competitive environment delivering quality service is considered as an essential strategy for success and survival. In the very competitive container terminals, service quality is important in attracting and retaining customers. The shipping companies are interested in speed and reliability from the terminals. The time a ship stays in a port must be minimised, and, therefore, the handling of containers must be executed in a fast and reliable way. The importance of customer service as a competitive strategy in container terminal has long been recognised. The growth in container volumes and higher productivity by Ngqura Container Terminal has created greater demand than before from its customers in the shipping business. The current growth in container volumes and increased customer demand has made the situation at NCT less encouraging at times, due to additional traffic of vessels awaiting to dock at the port creating congestion problems; resulting in unplanned lengthy dock occupation by vessels and the current status quo is affecting NCT strategy in terms of arrival docking and providing a quick response to customers. The Ngqura terminal is under increasing pressure from its customers and stakeholders to demonstrate that their services are customer-focused and that continuous performance improvement is being delivered. Therefore, a literature study and questionnaire survey forms the main input for this research combined with interviews with terminal managers. The purpose of this research is to examine the service quality concepts and offer an operational approach for the measurement of the quality of Ngqura Container Terminal services. The main research problem in this study was to identify customer service strategies that could be applied by Ngqura Container Terminal in order to maintain and exceed its business growth as well as customer expectations? The study employed the SERVQUAL model as a measuring tool in establishing the customers’ general expectations of a service and their perceptions of the service received at Ngqura Container Terminal. The five elements of SERVQUAL, which are tangibles, reliability, responsiveness, assurance, and empathy, were used to deal with and solve the main problem. Below are the sub-problems that have been identified in order to investigate and develop a research strategy: What is the customer’s perception of service quality at NCT?; What are the specific customer service requirements of NCT’s customers?; Does NCT’s service operations performance enable it to fulfill its customer service requirements?; How can the performance gap between customer service requirements and service operations performance be bridged?; Which service quality elements are important to customers for container terminals? This study wants to concentrate on the customers’ perception and evaluation toward service performance in Ngqura Container Terminal.
- Full Text:
- Date Issued: 2014
- Authors: Mtshiselwa, Mkhululi Terrence
- Date: 2014
- Subjects: SERVQUAL (Service quality framework) , Customer services -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/8955 , vital:26446
- Description: The container terminals play an increasingly important role in the economy of many countries. In today’s global competitive environment delivering quality service is considered as an essential strategy for success and survival. In the very competitive container terminals, service quality is important in attracting and retaining customers. The shipping companies are interested in speed and reliability from the terminals. The time a ship stays in a port must be minimised, and, therefore, the handling of containers must be executed in a fast and reliable way. The importance of customer service as a competitive strategy in container terminal has long been recognised. The growth in container volumes and higher productivity by Ngqura Container Terminal has created greater demand than before from its customers in the shipping business. The current growth in container volumes and increased customer demand has made the situation at NCT less encouraging at times, due to additional traffic of vessels awaiting to dock at the port creating congestion problems; resulting in unplanned lengthy dock occupation by vessels and the current status quo is affecting NCT strategy in terms of arrival docking and providing a quick response to customers. The Ngqura terminal is under increasing pressure from its customers and stakeholders to demonstrate that their services are customer-focused and that continuous performance improvement is being delivered. Therefore, a literature study and questionnaire survey forms the main input for this research combined with interviews with terminal managers. The purpose of this research is to examine the service quality concepts and offer an operational approach for the measurement of the quality of Ngqura Container Terminal services. The main research problem in this study was to identify customer service strategies that could be applied by Ngqura Container Terminal in order to maintain and exceed its business growth as well as customer expectations? The study employed the SERVQUAL model as a measuring tool in establishing the customers’ general expectations of a service and their perceptions of the service received at Ngqura Container Terminal. The five elements of SERVQUAL, which are tangibles, reliability, responsiveness, assurance, and empathy, were used to deal with and solve the main problem. Below are the sub-problems that have been identified in order to investigate and develop a research strategy: What is the customer’s perception of service quality at NCT?; What are the specific customer service requirements of NCT’s customers?; Does NCT’s service operations performance enable it to fulfill its customer service requirements?; How can the performance gap between customer service requirements and service operations performance be bridged?; Which service quality elements are important to customers for container terminals? This study wants to concentrate on the customers’ perception and evaluation toward service performance in Ngqura Container Terminal.
- Full Text:
- Date Issued: 2014
A decentralized multi-agent based network management system for ICT4D networks
- Authors: Matebese, Sithembiso
- Date: 2014
- Subjects: Microsoft� Word 2010
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11398 , http://hdl.handle.net/10353/d1019853
- Description: Network management is fundamental for assuring high quality services required by each user for the effective utilization of network resources. In this research, we propose the use of a decentralized, flexible and scalable Multi-Agent based system to monitor and manage rural broadband networks adaptively and efficiently. This mechanism is not novel as it has been used for high-speed, large-scale and distributed networks. This research investigates how software agents could collaborate in the process of managing rural broadband networks and developing an autonomous decentralized network management mechanism. In rural networks, network management is a challenging task because of lack of a reliable power supply, greater geographical distances, topographical barriers, and lack of technical support as well as computer repair facilities. This renders the network monitoring function complex and difficult. Since software agents are goal-driven, this research aims at developing a distributed management system that efficiently diagnoses errors on a given network and autonomously invokes effective changes to the network based on the goals defined on system agents. To make this possible, the Siyakhula Living Lab network was used as the research case study and existing network management system was reviewed and used as the basis for the proposed network management system. The proposed network management system uses JADE framework, Hyperic-Sigar API, Java networking programming and JESS scripting language to implement reasoning software agents. JADE and Java were used to develop the system agents with FIPA specifications. Hyperic-Sigar was used to collect the device information, Jpcap was used for collecting device network information and JESS for developing a rule engine for agents to reason about the device and network state. Even though the system is developed with Siyakhula Living Lab considerations, technically it can be used in any small-medium network because it is adaptable and scalable to various network infrastructure requirements. The proposed system consists of two types of agents, the MasterAgent and the NodeAgent. The MasterAgent resides on the device that has the agent platform and NodeAgent resides on devices connected to the network. The MasterAgent provides the network administrator with graphical and web user interfaces so that they can view network analysis and statistics. The agent platform provides agents with the executing environment and every agent, when started, is added to this platform. This system is platform independent as it has been tested on Linux, Mac and Windows platforms. The implemented system has been found to provide a suitable network management function to rural broadband networks that is: scalable in that more node agents can be added to the system to accommodate more devices in the network; autonomous in the ability to reason and execute actions based on the defined rules; fault-tolerant through being designed as a decentralized platform thereby reducing the Single Point of Failure (SPOF) in the system.
- Full Text:
- Date Issued: 2014
- Authors: Matebese, Sithembiso
- Date: 2014
- Subjects: Microsoft� Word 2010
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11398 , http://hdl.handle.net/10353/d1019853
- Description: Network management is fundamental for assuring high quality services required by each user for the effective utilization of network resources. In this research, we propose the use of a decentralized, flexible and scalable Multi-Agent based system to monitor and manage rural broadband networks adaptively and efficiently. This mechanism is not novel as it has been used for high-speed, large-scale and distributed networks. This research investigates how software agents could collaborate in the process of managing rural broadband networks and developing an autonomous decentralized network management mechanism. In rural networks, network management is a challenging task because of lack of a reliable power supply, greater geographical distances, topographical barriers, and lack of technical support as well as computer repair facilities. This renders the network monitoring function complex and difficult. Since software agents are goal-driven, this research aims at developing a distributed management system that efficiently diagnoses errors on a given network and autonomously invokes effective changes to the network based on the goals defined on system agents. To make this possible, the Siyakhula Living Lab network was used as the research case study and existing network management system was reviewed and used as the basis for the proposed network management system. The proposed network management system uses JADE framework, Hyperic-Sigar API, Java networking programming and JESS scripting language to implement reasoning software agents. JADE and Java were used to develop the system agents with FIPA specifications. Hyperic-Sigar was used to collect the device information, Jpcap was used for collecting device network information and JESS for developing a rule engine for agents to reason about the device and network state. Even though the system is developed with Siyakhula Living Lab considerations, technically it can be used in any small-medium network because it is adaptable and scalable to various network infrastructure requirements. The proposed system consists of two types of agents, the MasterAgent and the NodeAgent. The MasterAgent resides on the device that has the agent platform and NodeAgent resides on devices connected to the network. The MasterAgent provides the network administrator with graphical and web user interfaces so that they can view network analysis and statistics. The agent platform provides agents with the executing environment and every agent, when started, is added to this platform. This system is platform independent as it has been tested on Linux, Mac and Windows platforms. The implemented system has been found to provide a suitable network management function to rural broadband networks that is: scalable in that more node agents can be added to the system to accommodate more devices in the network; autonomous in the ability to reason and execute actions based on the defined rules; fault-tolerant through being designed as a decentralized platform thereby reducing the Single Point of Failure (SPOF) in the system.
- Full Text:
- Date Issued: 2014
A Diagnosis of School Governance in the Eastern Cape Province
- Authors: Ngonzo, Mthunywa Lawrence
- Date: 2014
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10353/1016 , vital:26518
- Description: This research conducts a diagnosis of school governance in the Eastern Cape Province with the overriding objective of determining the appropriate strategies that can be recommended for improving the effectiveness of school governance in the Eastern Cape Province. In a bid to achieve this overriding objective, the entire research process was guided by the research objectives and questions that examined; factors determining the effectiveness of school governance in the Eastern Cape Province, the effects of effective governance on performance of schools in the Eastern Cape Province, and the strategies which are used for improving school governance in the Eastern Cape Province. Although the secondary research was accomplished through the review and analysis of the relevant literatures and theories, the qualitative research approach was used in the primary research process. The findings of the study indicate that achieving effective school governance in the Eastern Cape Province is far from being attained for the reason that in terms of the applications of the principles for effective governance, the study reveals that the effective implementations of these principles in the Eastern Cape schools is marred by factors that include; lack of clear outline of SGBs, poor briefing of members about the roles of SGBs, poor consultations of members and stakeholders, poor representation of stakeholders, poor support of school’s staff, lack of well defined vision, and poor documentations of SGBs’ roles. Despite the fact that the findings of the study also indicate that the practices in the Eastern Cape schools are inappropriate for enhancing effective school governance, it was noted that there is still ineffective application of the strategies which can be used for improving school governance in the Eastern Cape Province. As the findings indicate, this certainly undermines the effectiveness of school governance in the Eastern Cape Province. While drawing from both the primary and secondary findings of the study, it was recommended that the school governing bodies in the Eastern Cape Province must; apply the six main principles for effective governance, apply the core components or pillars of good governance and consider implementing the strategies encompassing; considering that common interest and core business issues is one of the strategies, ensuring that the roles, objectives, functions and powers of the school council are clearly understood by all council members, effective planning, policy making and reporting, induction and professional development and learning, communication and information sharing, monitoring, evaluation and improvement. It was suggested that the suggested area for further study would be; “The effects of stakeholders’ involvement on the performance of School Governing Bodies.”
- Full Text:
- Date Issued: 2014
- Authors: Ngonzo, Mthunywa Lawrence
- Date: 2014
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10353/1016 , vital:26518
- Description: This research conducts a diagnosis of school governance in the Eastern Cape Province with the overriding objective of determining the appropriate strategies that can be recommended for improving the effectiveness of school governance in the Eastern Cape Province. In a bid to achieve this overriding objective, the entire research process was guided by the research objectives and questions that examined; factors determining the effectiveness of school governance in the Eastern Cape Province, the effects of effective governance on performance of schools in the Eastern Cape Province, and the strategies which are used for improving school governance in the Eastern Cape Province. Although the secondary research was accomplished through the review and analysis of the relevant literatures and theories, the qualitative research approach was used in the primary research process. The findings of the study indicate that achieving effective school governance in the Eastern Cape Province is far from being attained for the reason that in terms of the applications of the principles for effective governance, the study reveals that the effective implementations of these principles in the Eastern Cape schools is marred by factors that include; lack of clear outline of SGBs, poor briefing of members about the roles of SGBs, poor consultations of members and stakeholders, poor representation of stakeholders, poor support of school’s staff, lack of well defined vision, and poor documentations of SGBs’ roles. Despite the fact that the findings of the study also indicate that the practices in the Eastern Cape schools are inappropriate for enhancing effective school governance, it was noted that there is still ineffective application of the strategies which can be used for improving school governance in the Eastern Cape Province. As the findings indicate, this certainly undermines the effectiveness of school governance in the Eastern Cape Province. While drawing from both the primary and secondary findings of the study, it was recommended that the school governing bodies in the Eastern Cape Province must; apply the six main principles for effective governance, apply the core components or pillars of good governance and consider implementing the strategies encompassing; considering that common interest and core business issues is one of the strategies, ensuring that the roles, objectives, functions and powers of the school council are clearly understood by all council members, effective planning, policy making and reporting, induction and professional development and learning, communication and information sharing, monitoring, evaluation and improvement. It was suggested that the suggested area for further study would be; “The effects of stakeholders’ involvement on the performance of School Governing Bodies.”
- Full Text:
- Date Issued: 2014
A discussion and comparison of company legislation and tax legislation in South Africa, in relation to amalgamations and mergers
- Authors: Sloane, Justin
- Date: 2014
- Subjects: Corporation law -- South Africa , Taxation -- Law and legislation -- South Africa , Consolidation and merger of corporations -- South Africa , Income tax -- South Africa , Capital gains tax -- South Africa , Value-added tax -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:908 , http://hdl.handle.net/10962/d1013028
- Description: In his 2012 Budget Review, the Minister of Finance, Pravin Gordhan acknowledged that the introduction of the "new" Companies Act had given rise to certain anomalies in relation to tax and subsequently announced that the South African government would undertake to review the nature of company mergers, acquisitions and other restructurings with the view of possibly amending the Income Tax Act and/or the "new" Companies Act, to bring the two legislations in line with one another. These anomalies give rise to the present research. The literature reviewed in the present research revealed and identified the inconsistencies that exist between the "new" Companies Act, 71 of 2008 and the Income Tax Act, 58 of 1962, specifically the inconsistencies that exist in respect of the newly introduced amalgamation or merger provisions as set out in the "new" Companies Act. Moreover, this research was undertaken to identify the potential tax implications insofar as they relate to amalgamation transactions and, in particular, the potential tax implications where such transactions, because of the anomalies, fall outside the ambit section 44 of the Income Tax Act, which would in normal circumstances provide for tax "rollover relief". In this regard, the present research identified the possible income tax, capital gains tax, value-added tax, transfer duty tax and securities transfer tax affected by an amalgamation transaction, on the assumption that the "rollover relief" in section 44 of the Income Tax Act does not apply.
- Full Text:
- Date Issued: 2014
- Authors: Sloane, Justin
- Date: 2014
- Subjects: Corporation law -- South Africa , Taxation -- Law and legislation -- South Africa , Consolidation and merger of corporations -- South Africa , Income tax -- South Africa , Capital gains tax -- South Africa , Value-added tax -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:908 , http://hdl.handle.net/10962/d1013028
- Description: In his 2012 Budget Review, the Minister of Finance, Pravin Gordhan acknowledged that the introduction of the "new" Companies Act had given rise to certain anomalies in relation to tax and subsequently announced that the South African government would undertake to review the nature of company mergers, acquisitions and other restructurings with the view of possibly amending the Income Tax Act and/or the "new" Companies Act, to bring the two legislations in line with one another. These anomalies give rise to the present research. The literature reviewed in the present research revealed and identified the inconsistencies that exist between the "new" Companies Act, 71 of 2008 and the Income Tax Act, 58 of 1962, specifically the inconsistencies that exist in respect of the newly introduced amalgamation or merger provisions as set out in the "new" Companies Act. Moreover, this research was undertaken to identify the potential tax implications insofar as they relate to amalgamation transactions and, in particular, the potential tax implications where such transactions, because of the anomalies, fall outside the ambit section 44 of the Income Tax Act, which would in normal circumstances provide for tax "rollover relief". In this regard, the present research identified the possible income tax, capital gains tax, value-added tax, transfer duty tax and securities transfer tax affected by an amalgamation transaction, on the assumption that the "rollover relief" in section 44 of the Income Tax Act does not apply.
- Full Text:
- Date Issued: 2014
A field investigation into the impact of task demands on worker responses in the South African forestry silviculture sector
- Authors: Parker, Rhiannon Jennifer
- Date: 2014
- Subjects: Forests and forestry -- South Africa -- KwaZulu-Natal , Blue collar workers -- South Africa -- KwaZulu-Natal , Manual work -- South Africa -- KwaZulu-Natal , Work -- Physiological aspects , Human mechanics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5157 , http://hdl.handle.net/10962/d1015645
- Description: Background: In South Africa, limited research has focused on the task demands and workers responses associated with forestry silviculture work, particularly pitting and planting. The methods currently in use are manual, but despite our lack of understanding of the existing demands, advances in forestry engineering have resulted in an introduction of semi-mechanised versions of these tasks. This project aimed to compare the task demands of silviculture tasks using the current manual techniques and the more modern, semi-mechanised techniques. Methods: A holistic investigation focused on the worker characteristics of a sample of black male pitters and black female planters from the Kwa-Zulu Natal forestry industry, as well as biomechanical (spinal kinematics and L5/S1 forces), physiological (heart rate, oxygen consumption and energy expenditure) and psychophysical (ratings of perceived exertion and body discomfort) responses associated with manual and semi-mechanised pitting and planting. Results: The pitting task saw significant improvements in the spinal kinematic measures as a result of the increased mechanisation, with eight of the 16 recorded variables decreasing to a lower level of risk classification. Physiologically, the manual task was associated with a mean heart rate of 157 bt.min⁻¹ and absolute energy expenditure of 11.27 kcal.min⁻¹, which were not found to be significantly different to the values of 143 bt.min⁻¹ and 9.8 kcal.min⁻¹ recorded during the semi-mechanised technique. Psychophysical responses indicated that the workers perceived manual pitting to be more physically demanding than the semi-mechanised method. The manual and semi-mechanised planting tasks were, in general, found to be acceptable from a spinal kinematics perspective, with the majority of variables classified as low risk. However, the maximum sagittal angle was reduced by more than 20 degrees as a result of the new equipment. The physiological and psychophysical demands associated with manual planting were found to be within acceptable limits. Conclusion: In terms of pitting, it can tentatively be concluded that the semi-mechanised technique is better than the manual one, based on the biomechanical and psychophysical findings, however physiological demands require further investigation. When considering the planting techniques, the semi-mechanised method showed a slight improvement from the biomechanical perspective, but further physiological and psychophysical investigations are needed.
- Full Text:
- Date Issued: 2014
- Authors: Parker, Rhiannon Jennifer
- Date: 2014
- Subjects: Forests and forestry -- South Africa -- KwaZulu-Natal , Blue collar workers -- South Africa -- KwaZulu-Natal , Manual work -- South Africa -- KwaZulu-Natal , Work -- Physiological aspects , Human mechanics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5157 , http://hdl.handle.net/10962/d1015645
- Description: Background: In South Africa, limited research has focused on the task demands and workers responses associated with forestry silviculture work, particularly pitting and planting. The methods currently in use are manual, but despite our lack of understanding of the existing demands, advances in forestry engineering have resulted in an introduction of semi-mechanised versions of these tasks. This project aimed to compare the task demands of silviculture tasks using the current manual techniques and the more modern, semi-mechanised techniques. Methods: A holistic investigation focused on the worker characteristics of a sample of black male pitters and black female planters from the Kwa-Zulu Natal forestry industry, as well as biomechanical (spinal kinematics and L5/S1 forces), physiological (heart rate, oxygen consumption and energy expenditure) and psychophysical (ratings of perceived exertion and body discomfort) responses associated with manual and semi-mechanised pitting and planting. Results: The pitting task saw significant improvements in the spinal kinematic measures as a result of the increased mechanisation, with eight of the 16 recorded variables decreasing to a lower level of risk classification. Physiologically, the manual task was associated with a mean heart rate of 157 bt.min⁻¹ and absolute energy expenditure of 11.27 kcal.min⁻¹, which were not found to be significantly different to the values of 143 bt.min⁻¹ and 9.8 kcal.min⁻¹ recorded during the semi-mechanised technique. Psychophysical responses indicated that the workers perceived manual pitting to be more physically demanding than the semi-mechanised method. The manual and semi-mechanised planting tasks were, in general, found to be acceptable from a spinal kinematics perspective, with the majority of variables classified as low risk. However, the maximum sagittal angle was reduced by more than 20 degrees as a result of the new equipment. The physiological and psychophysical demands associated with manual planting were found to be within acceptable limits. Conclusion: In terms of pitting, it can tentatively be concluded that the semi-mechanised technique is better than the manual one, based on the biomechanical and psychophysical findings, however physiological demands require further investigation. When considering the planting techniques, the semi-mechanised method showed a slight improvement from the biomechanical perspective, but further physiological and psychophysical investigations are needed.
- Full Text:
- Date Issued: 2014
A Flexible Approach for the Application of Immersive Audio to an Installation Performance:
- Gurdan, Robby, Foss, Richard
- Authors: Gurdan, Robby , Foss, Richard
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426732 , vital:72387 , https://patentimages.storage.googleapis.com/28/4a/94/1113bd7074ad90/US8862755.pdf /
- Description: An apparatus for modifying a command message (CMD) received from a source apparatus to control a target device parameter of a target apparatus within a digital multimedia network, wherein a hierarchical parameter address (HPA) or a parameter value contained in said command message (CMD) is changed according to at least one change script to provide a modified command message (CMD′).
- Full Text:
- Date Issued: 2014
- Authors: Gurdan, Robby , Foss, Richard
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426732 , vital:72387 , https://patentimages.storage.googleapis.com/28/4a/94/1113bd7074ad90/US8862755.pdf /
- Description: An apparatus for modifying a command message (CMD) received from a source apparatus to control a target device parameter of a target apparatus within a digital multimedia network, wherein a hierarchical parameter address (HPA) or a parameter value contained in said command message (CMD) is changed according to at least one change script to provide a modified command message (CMD′).
- Full Text:
- Date Issued: 2014
A formalised ontology for network attack classification
- Authors: Van Heerden, Renier Pelser
- Date: 2014
- Subjects: Computer networks -- Security measures Computer security Computer crimes -- Investigation Computer crimes -- Prevention
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4691 , http://hdl.handle.net/10962/d1011603
- Description: One of the most popular attack vectors against computers are their network connections. Attacks on computers through their networks are commonplace and have various levels of complexity. This research formally describes network-based computer attacks in the form of a story, formally and within an ontology. The ontology categorises network attacks where attack scenarios are the focal class. This class consists of: Denial-of- Service, Industrial Espionage, Web Defacement, Unauthorised Data Access, Financial Theft, Industrial Sabotage, Cyber-Warfare, Resource Theft, System Compromise, and Runaway Malware. This ontology was developed by building a taxonomy and a temporal network attack model. Network attack instances (also know as individuals) are classified according to their respective attack scenarios, with the use of an automated reasoner within the ontology. The automated reasoner deductions are verified formally; and via the automated reasoner, a relaxed set of scenarios is determined, which is relevant in a near real-time environment. A prototype system (called Aeneas) was developed to classify network-based attacks. Aeneas integrates the sensors into a detection system that can classify network attacks in a near real-time environment. To verify the ontology and the prototype Aeneas, a virtual test bed was developed in which network-based attacks were generated to verify the detection system. Aeneas was able to detect incoming attacks and classify them according to their scenario. The novel part of this research is the attack scenarios that are described in the form of a story, as well as formally and in an ontology. The ontology is used in a novel way to determine to which class attack instances belong and how the network attack ontology is affected in a near real-time environment.
- Full Text:
- Date Issued: 2014
- Authors: Van Heerden, Renier Pelser
- Date: 2014
- Subjects: Computer networks -- Security measures Computer security Computer crimes -- Investigation Computer crimes -- Prevention
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4691 , http://hdl.handle.net/10962/d1011603
- Description: One of the most popular attack vectors against computers are their network connections. Attacks on computers through their networks are commonplace and have various levels of complexity. This research formally describes network-based computer attacks in the form of a story, formally and within an ontology. The ontology categorises network attacks where attack scenarios are the focal class. This class consists of: Denial-of- Service, Industrial Espionage, Web Defacement, Unauthorised Data Access, Financial Theft, Industrial Sabotage, Cyber-Warfare, Resource Theft, System Compromise, and Runaway Malware. This ontology was developed by building a taxonomy and a temporal network attack model. Network attack instances (also know as individuals) are classified according to their respective attack scenarios, with the use of an automated reasoner within the ontology. The automated reasoner deductions are verified formally; and via the automated reasoner, a relaxed set of scenarios is determined, which is relevant in a near real-time environment. A prototype system (called Aeneas) was developed to classify network-based attacks. Aeneas integrates the sensors into a detection system that can classify network attacks in a near real-time environment. To verify the ontology and the prototype Aeneas, a virtual test bed was developed in which network-based attacks were generated to verify the detection system. Aeneas was able to detect incoming attacks and classify them according to their scenario. The novel part of this research is the attack scenarios that are described in the form of a story, as well as formally and in an ontology. The ontology is used in a novel way to determine to which class attack instances belong and how the network attack ontology is affected in a near real-time environment.
- Full Text:
- Date Issued: 2014
A framework for business leadership in Africa
- Authors: Whitley, Elwyn
- Date: 2014
- Subjects: Leadership -- Africa Success in business , Management -- Africa Business Industrial management -- Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/45814 , vital:39219
- Description: In a fast moving, rapidly changing and highly competitive world the importance of strong leadership in both government and business cannot be over emphasised. The realisation that leadership is necessary for the organisation’s success and is key for the organisation’s survival (Alimo-Metcalfe and Alban- Metcalfe, 2008) is evident in the increasing focus on the concept over the last three to four decades. As the world becomes more of a ‘global village’ adapting to doing business in this new environment will require a leader who not only has the traditional skills set but also has the additional knowledge, skills and “mindset to navigate through the complexities brought on by moving beyond one's traditional borders” (Cohen, 2010. p. 3). This is of particular importance to Africa with the influx of foreign investors attracted by the growth opportunities that Africa offers, looking to expand their markets and in doing so imposing western norms and standards on local operations, in complex environments. Unfortunately Western leadership theories have not always been successful as Africans have found that in order to embrace Western ideals they need to relinquish some of their own beliefs. This highlights an opportunity to explore a possible hybrid leadership approach that harmonises the Western approach that is based on facts, logic and the nature of reality with the African humanistic orientation. The main aim of this study is to research the concept, principles, and characteristics of a small sample of business leaders in Africa in order to identify the factors that contribute to the leader’s success in a global business operating in Africa. By applying qualitative research methodology which includes an individual narrative written by each Managing Director, semistructured interviews and focus groups, a framework for business leadership in Africa was developed.
- Full Text:
- Date Issued: 2014
- Authors: Whitley, Elwyn
- Date: 2014
- Subjects: Leadership -- Africa Success in business , Management -- Africa Business Industrial management -- Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/45814 , vital:39219
- Description: In a fast moving, rapidly changing and highly competitive world the importance of strong leadership in both government and business cannot be over emphasised. The realisation that leadership is necessary for the organisation’s success and is key for the organisation’s survival (Alimo-Metcalfe and Alban- Metcalfe, 2008) is evident in the increasing focus on the concept over the last three to four decades. As the world becomes more of a ‘global village’ adapting to doing business in this new environment will require a leader who not only has the traditional skills set but also has the additional knowledge, skills and “mindset to navigate through the complexities brought on by moving beyond one's traditional borders” (Cohen, 2010. p. 3). This is of particular importance to Africa with the influx of foreign investors attracted by the growth opportunities that Africa offers, looking to expand their markets and in doing so imposing western norms and standards on local operations, in complex environments. Unfortunately Western leadership theories have not always been successful as Africans have found that in order to embrace Western ideals they need to relinquish some of their own beliefs. This highlights an opportunity to explore a possible hybrid leadership approach that harmonises the Western approach that is based on facts, logic and the nature of reality with the African humanistic orientation. The main aim of this study is to research the concept, principles, and characteristics of a small sample of business leaders in Africa in order to identify the factors that contribute to the leader’s success in a global business operating in Africa. By applying qualitative research methodology which includes an individual narrative written by each Managing Director, semistructured interviews and focus groups, a framework for business leadership in Africa was developed.
- Full Text:
- Date Issued: 2014
A framework for high speed lexical classification of malicious URLs
- Authors: Egan, Shaun Peter
- Date: 2014
- Subjects: Internet -- Security measures -- Research , Uniform Resource Identifiers -- Security measures -- Research , Neural networks (Computer science) -- Research , Computer security -- Research , Computer crimes -- Prevention , Phishing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4696 , http://hdl.handle.net/10962/d1011933 , Internet -- Security measures -- Research , Uniform Resource Identifiers -- Security measures -- Research , Neural networks (Computer science) -- Research , Computer security -- Research , Computer crimes -- Prevention , Phishing
- Description: Phishing attacks employ social engineering to target end-users, with the goal of stealing identifying or sensitive information. This information is used in activities such as identity theft or financial fraud. During a phishing campaign, attackers distribute URLs which; along with false information, point to fraudulent resources in an attempt to deceive users into requesting the resource. These URLs are made obscure through the use of several techniques which make automated detection difficult. Current methods used to detect malicious URLs face multiple problems which attackers use to their advantage. These problems include: the time required to react to new attacks; shifts in trends in URL obfuscation and usability problems caused by the latency incurred by the lookups required by these approaches. A new method of identifying malicious URLs using Artificial Neural Networks (ANNs) has been shown to be effective by several authors. The simple method of classification performed by ANNs result in very high classification speeds with little impact on usability. Samples used for the training, validation and testing of these ANNs are gathered from Phishtank and Open Directory. Words selected from the different sections of the samples are used to create a `Bag-of-Words (BOW)' which is used as a binary input vector indicating the presence of a word for a given sample. Twenty additional features which measure lexical attributes of the sample are used to increase classification accuracy. A framework that is capable of generating these classifiers in an automated fashion is implemented. These classifiers are automatically stored on a remote update distribution service which has been built to supply updates to classifier implementations. An example browser plugin is created and uses ANNs provided by this service. It is both capable of classifying URLs requested by a user in real time and is able to block these requests. The framework is tested in terms of training time and classification accuracy. Classification speed and the effectiveness of compression algorithms on the data required to distribute updates is tested. It is concluded that it is possible to generate these ANNs in a frequent fashion, and in a method that is small enough to distribute easily. It is also shown that classifications are made at high-speed with high-accuracy, resulting in little impact on usability.
- Full Text:
- Date Issued: 2014
- Authors: Egan, Shaun Peter
- Date: 2014
- Subjects: Internet -- Security measures -- Research , Uniform Resource Identifiers -- Security measures -- Research , Neural networks (Computer science) -- Research , Computer security -- Research , Computer crimes -- Prevention , Phishing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4696 , http://hdl.handle.net/10962/d1011933 , Internet -- Security measures -- Research , Uniform Resource Identifiers -- Security measures -- Research , Neural networks (Computer science) -- Research , Computer security -- Research , Computer crimes -- Prevention , Phishing
- Description: Phishing attacks employ social engineering to target end-users, with the goal of stealing identifying or sensitive information. This information is used in activities such as identity theft or financial fraud. During a phishing campaign, attackers distribute URLs which; along with false information, point to fraudulent resources in an attempt to deceive users into requesting the resource. These URLs are made obscure through the use of several techniques which make automated detection difficult. Current methods used to detect malicious URLs face multiple problems which attackers use to their advantage. These problems include: the time required to react to new attacks; shifts in trends in URL obfuscation and usability problems caused by the latency incurred by the lookups required by these approaches. A new method of identifying malicious URLs using Artificial Neural Networks (ANNs) has been shown to be effective by several authors. The simple method of classification performed by ANNs result in very high classification speeds with little impact on usability. Samples used for the training, validation and testing of these ANNs are gathered from Phishtank and Open Directory. Words selected from the different sections of the samples are used to create a `Bag-of-Words (BOW)' which is used as a binary input vector indicating the presence of a word for a given sample. Twenty additional features which measure lexical attributes of the sample are used to increase classification accuracy. A framework that is capable of generating these classifiers in an automated fashion is implemented. These classifiers are automatically stored on a remote update distribution service which has been built to supply updates to classifier implementations. An example browser plugin is created and uses ANNs provided by this service. It is both capable of classifying URLs requested by a user in real time and is able to block these requests. The framework is tested in terms of training time and classification accuracy. Classification speed and the effectiveness of compression algorithms on the data required to distribute updates is tested. It is concluded that it is possible to generate these ANNs in a frequent fashion, and in a method that is small enough to distribute easily. It is also shown that classifications are made at high-speed with high-accuracy, resulting in little impact on usability.
- Full Text:
- Date Issued: 2014
A framework for implementation of ICT4D initiatives in the Eastern Cape province of South Africa
- Authors: Phingilili, Gcotyelwa
- Date: 2014
- Subjects: Information and Communication Technologies , ICT4D -- Development -- Rural community , Implementation -- ICT initiatives
- Language: English
- Type: Thesis , Masters , MCom (Information Systems)
- Identifier: vital:11146 , http://hdl.handle.net/10353/d1017789 , Information and Communication Technologies , ICT4D -- Development -- Rural community , Implementation -- ICT initiatives
- Description: South Africa’s rural communities have received Information and Communication Technologies services through initiatives such as tele-centres, living labs, Thusong service centres and donations of computer applications. There is need, with little plans in place to ensure that the rural communities will benefit from those initiatives. As a result of this, it is necessary to establish a framework for implementing Information and Communication Technologies for development initiatives in order to ensure successful implementation of these initiatives in rural communities. Literature shows that in order to successfully implement an ICT initiative for rural communities, there should be active engagement with ICT stakeholders, consultation of Information and Communication Technologies policies, presence of ICT infrastructure, ICT services, monitoring, evaluating, training and maintenance. Current literature on ICT developments shows that in order to successfully implement an ICT initiative for rural communities, there should be active engagement with ICT stakeholders, consultation of ICT policies, and presence of ICT infrastructure, ICT services, monitoring, evaluating, training and maintenance. Unstructured interviews were used as a research method to collect primary data that was used as a basis to develop the proposed framework. Findings from the studies carried out indicated that several ICT4D initiatives which were abandoned due to challenges such lack of proper resources, trainings, lack of local content, access, lack of ownership and lack of stakeholders’ involvement. This study presents a framework for implementing ICT for development initiatives in rural communities which has been developed in order to reduce the number of initiatives that are abandoned or which end up not serving their intended purpose in rural communities of South Africa.
- Full Text:
- Date Issued: 2014
- Authors: Phingilili, Gcotyelwa
- Date: 2014
- Subjects: Information and Communication Technologies , ICT4D -- Development -- Rural community , Implementation -- ICT initiatives
- Language: English
- Type: Thesis , Masters , MCom (Information Systems)
- Identifier: vital:11146 , http://hdl.handle.net/10353/d1017789 , Information and Communication Technologies , ICT4D -- Development -- Rural community , Implementation -- ICT initiatives
- Description: South Africa’s rural communities have received Information and Communication Technologies services through initiatives such as tele-centres, living labs, Thusong service centres and donations of computer applications. There is need, with little plans in place to ensure that the rural communities will benefit from those initiatives. As a result of this, it is necessary to establish a framework for implementing Information and Communication Technologies for development initiatives in order to ensure successful implementation of these initiatives in rural communities. Literature shows that in order to successfully implement an ICT initiative for rural communities, there should be active engagement with ICT stakeholders, consultation of Information and Communication Technologies policies, presence of ICT infrastructure, ICT services, monitoring, evaluating, training and maintenance. Current literature on ICT developments shows that in order to successfully implement an ICT initiative for rural communities, there should be active engagement with ICT stakeholders, consultation of ICT policies, and presence of ICT infrastructure, ICT services, monitoring, evaluating, training and maintenance. Unstructured interviews were used as a research method to collect primary data that was used as a basis to develop the proposed framework. Findings from the studies carried out indicated that several ICT4D initiatives which were abandoned due to challenges such lack of proper resources, trainings, lack of local content, access, lack of ownership and lack of stakeholders’ involvement. This study presents a framework for implementing ICT for development initiatives in rural communities which has been developed in order to reduce the number of initiatives that are abandoned or which end up not serving their intended purpose in rural communities of South Africa.
- Full Text:
- Date Issued: 2014
A framework for the management of environmental information in Higher Education Institutions
- Authors: Jonamu, Blessing Tapiwa
- Date: 2014
- Subjects: Sustainability , Universities and colleges , Environmental management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10492 , http://hdl.handle.net/10948/d1020620
- Description: Higher Education Institutions (HEIs) are not immune to the global environment problems. An increasing awareness of the environmental responsibilities of HEIs has led researchers to investigate the role of environmental information and Environmental Management Information Systems (EMISs) in HEIs. EMISs play a major role in environmental management and environmental decision making in HEIs. Internationally, an increasing number of HEIs are embracing the concept of ‘sustainable HEIs’ by undertaking green campus initiatives. HEIs often use diverse information systems, some of which are manual systems, proven to be inefficient and this gives rise to redundant and inconsistent databases which result in non-compliance with regulations, confusion and lack of co-ordinated effort. There is therefore need for an integrated, comprehensive software system and framework which can assist with the efficient management of environmental information at South African HEIs. This study fills a gap in the field of environmental sustainability at HEIs as the evaluation of existing sustainability programs has shown common weakness such as: Failure to effectively set baselines, flaws in data acquisition and management and missing documentation. The aim of this study is to propose a framework for Environmental Information Management (EIM) in HEIs. The framework includes guidelines related to the components of the framework which can also be used to perform a gap analysis to facilitate the improved design of effective and efficient EIM processes and data stores. The Design Science Research (DSR) methodology is the research methodology used in the development of the two artifacts of this study namely: The EIM framework for HEIs and an EMIS prototype to serve as proof of concept. Problem identification and motivation was the first activity of the DSR which was done through a rigorous literature review and an investigation and evaluation of extant systems. This resulted in the design of an initial EIM framework for HEIs. Nelson Mandela Metropolitan University (NMMU) was the HEI used as the case study. The EIM framework was applied at NMMU and this enabled the researcher to understand the current As-Is EIM processes at NMMU and this resulted in clear objectives of a solution. The EMIS prototype (data warehouse) was then designed and implemented based on the theoretical framework. Three sets of evaluations were done to determine the acceptance of the EIM framework for HEIs and the performance of the EMIS prototype. The EIM framework was generally positively accepted and minor suggestions were made. An updated version of the EIM framework was proposed and evaluated. The experimental evaluation results showed that the EMIS prototype was efficient and effective. The contribution of this study is an EIM framework for HEIs and an implementation of an EMIS (EnviroDW) at NMMU that could be utilised by other HEIs.
- Full Text:
- Date Issued: 2014
- Authors: Jonamu, Blessing Tapiwa
- Date: 2014
- Subjects: Sustainability , Universities and colleges , Environmental management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10492 , http://hdl.handle.net/10948/d1020620
- Description: Higher Education Institutions (HEIs) are not immune to the global environment problems. An increasing awareness of the environmental responsibilities of HEIs has led researchers to investigate the role of environmental information and Environmental Management Information Systems (EMISs) in HEIs. EMISs play a major role in environmental management and environmental decision making in HEIs. Internationally, an increasing number of HEIs are embracing the concept of ‘sustainable HEIs’ by undertaking green campus initiatives. HEIs often use diverse information systems, some of which are manual systems, proven to be inefficient and this gives rise to redundant and inconsistent databases which result in non-compliance with regulations, confusion and lack of co-ordinated effort. There is therefore need for an integrated, comprehensive software system and framework which can assist with the efficient management of environmental information at South African HEIs. This study fills a gap in the field of environmental sustainability at HEIs as the evaluation of existing sustainability programs has shown common weakness such as: Failure to effectively set baselines, flaws in data acquisition and management and missing documentation. The aim of this study is to propose a framework for Environmental Information Management (EIM) in HEIs. The framework includes guidelines related to the components of the framework which can also be used to perform a gap analysis to facilitate the improved design of effective and efficient EIM processes and data stores. The Design Science Research (DSR) methodology is the research methodology used in the development of the two artifacts of this study namely: The EIM framework for HEIs and an EMIS prototype to serve as proof of concept. Problem identification and motivation was the first activity of the DSR which was done through a rigorous literature review and an investigation and evaluation of extant systems. This resulted in the design of an initial EIM framework for HEIs. Nelson Mandela Metropolitan University (NMMU) was the HEI used as the case study. The EIM framework was applied at NMMU and this enabled the researcher to understand the current As-Is EIM processes at NMMU and this resulted in clear objectives of a solution. The EMIS prototype (data warehouse) was then designed and implemented based on the theoretical framework. Three sets of evaluations were done to determine the acceptance of the EIM framework for HEIs and the performance of the EMIS prototype. The EIM framework was generally positively accepted and minor suggestions were made. An updated version of the EIM framework was proposed and evaluated. The experimental evaluation results showed that the EMIS prototype was efficient and effective. The contribution of this study is an EIM framework for HEIs and an implementation of an EMIS (EnviroDW) at NMMU that could be utilised by other HEIs.
- Full Text:
- Date Issued: 2014
A framework to elicit user requirements for information systems: a localised participatory approach from Southern Africa
- Authors: Tyukala, Mkhululi
- Date: 2014
- Subjects: Information technology -- Africa, Southern , User-centered system design -- Africa, Southern , Management information systems -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/4546 , vital:20615
- Description: The “What” and “Why” in information system development in resource restricted environments is already well covered in literature. However, the “How” to do it still has not been explored. This thesis reports on the development of a locally flavoured participatory user requirements elicitation framework for the development of information systems in resource restricted environments. It uses existing participatory design practices, user requirements elicitation literature and local participatory norms and traditions to achieve this. In doing so, it takes a step towards the way information systems could be developed in resource restricted environments. The topic of this thesis is mainly motivated by the recent calls in existing literature for developing countries to start developing their own information systems in order to address their own requirements. Accordingly, and to lay a foundation towards the realisation of this goal, this research is positioned within the user requirements elicitation region of information systems development. Current user requirements elicitation methods use traditional methods where experts/designers ask system users questions through interviews or learn about their environment through observations. This research proposes a shift from this approach to one that not only views users as equal partners in the elicitation process but in the whole information systems development process. This is in the spirit of participatory design, which was developed in Scandinavia more than four decades ago. Further, recent research in participatory design emphasises the importance of its contextual nature and concedes that there is no single best practice for participatory design in information systems that applies to all contexts. This research explores the information systems development discourse in resource restricted environments in Africa. Its purpose is to enhance understanding of the local contexts, thus providing new insights on how to develop a framework that speaks to local challenges using norms and traditions in order to develop information systems that address local requirements. Thus, the main contribution of this research lies in laying a foundation for a locally flavoured participatory approach for information systems development in resource restricted environments. It contributes to the existing information systems development, participatory design and user requirements elicitation body of knowledge by developing a framework for participatory user requirements elicitation. In addition, it contributes to the participatory design body of knowledge by introducing an age-old African participatory decisionmaking approach to the academic participatory design community. In doing so, it adopts the meaning of participation from an African value system point of view, which is something that has only been previously explored in the Nordic countries and North America. Finally, recommendations for the application, limitations and avenues for further research are incorporated into the findings of this research.
- Full Text:
- Date Issued: 2014
- Authors: Tyukala, Mkhululi
- Date: 2014
- Subjects: Information technology -- Africa, Southern , User-centered system design -- Africa, Southern , Management information systems -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/4546 , vital:20615
- Description: The “What” and “Why” in information system development in resource restricted environments is already well covered in literature. However, the “How” to do it still has not been explored. This thesis reports on the development of a locally flavoured participatory user requirements elicitation framework for the development of information systems in resource restricted environments. It uses existing participatory design practices, user requirements elicitation literature and local participatory norms and traditions to achieve this. In doing so, it takes a step towards the way information systems could be developed in resource restricted environments. The topic of this thesis is mainly motivated by the recent calls in existing literature for developing countries to start developing their own information systems in order to address their own requirements. Accordingly, and to lay a foundation towards the realisation of this goal, this research is positioned within the user requirements elicitation region of information systems development. Current user requirements elicitation methods use traditional methods where experts/designers ask system users questions through interviews or learn about their environment through observations. This research proposes a shift from this approach to one that not only views users as equal partners in the elicitation process but in the whole information systems development process. This is in the spirit of participatory design, which was developed in Scandinavia more than four decades ago. Further, recent research in participatory design emphasises the importance of its contextual nature and concedes that there is no single best practice for participatory design in information systems that applies to all contexts. This research explores the information systems development discourse in resource restricted environments in Africa. Its purpose is to enhance understanding of the local contexts, thus providing new insights on how to develop a framework that speaks to local challenges using norms and traditions in order to develop information systems that address local requirements. Thus, the main contribution of this research lies in laying a foundation for a locally flavoured participatory approach for information systems development in resource restricted environments. It contributes to the existing information systems development, participatory design and user requirements elicitation body of knowledge by developing a framework for participatory user requirements elicitation. In addition, it contributes to the participatory design body of knowledge by introducing an age-old African participatory decisionmaking approach to the academic participatory design community. In doing so, it adopts the meaning of participation from an African value system point of view, which is something that has only been previously explored in the Nordic countries and North America. Finally, recommendations for the application, limitations and avenues for further research are incorporated into the findings of this research.
- Full Text:
- Date Issued: 2014
A geological, petrological and mineralogical study of the UG3 chromitite seam at Modikwa Platinum Mine : significance to exploration and PGE resources
- Authors: Machumele, Nkateko Jones
- Date: 2014
- Subjects: Modikwa Platinum Mine (South Africa) , Chromite -- South Africa -- Limpopo , Geology -- South Africa -- Limpopo , Petrology -- South Africa -- Limpopo , Mineralogy -- South Africa -- Limpopo , Platinum mines and mining -- South Africa -- Limpopo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5074 , http://hdl.handle.net/10962/d1013553
- Description: The UG3 at Modikwa Platinum Mine occurs as a platiniferous, planar chromitite seam. It is stratigraphically located in the Upper Critical Zone of the Eastern Bushveld Complex. Field work study comprise of underground mapping, sampling, surface mapping, borehole core logging, microprobing and microscopic investigations carried out at the Rhodes University. The UG3 at the Modikwa Platinum Mine is about 22cm thick chromitite seam underlain by a white fine grained anorthosite and overlain by a brown medium grained feldspathic pyroxenite. It is an incomplete cyclic unit consisting of chromite and feldspathic pyroxenite. The UG3 reef at the Modikwa Platinum Mine lease area represents a Platinum Group Metal resource of 300 million tons of ore at an in situ grade of 2.5g/t. Under the current market conditions the UG3 reef remains unprofitable to mine in an underground operation due to the operational cost involved. However, it has been illustrated that the UG3 chromitite seam can increase profit margins in an open pit operation provided it is mined together with the economic UG2 chromitite seam. The extraction of the UG3 as ore in the four Modikwa UG2 open pits would result in a combined operating cash profit of R330 million. The UG3 chromitite seam is platiniferous. The platinum-group minerals (PGM) range in size from less than 10μm to about 70μm. The PGMs are associated with sulphides and are both located in the interstitial silicates and are concentrated in the chromitite seam. The PGMs show a strong preference to contact boundaries of the silicate grains, the chromite grains and the sulphide phases. In some instances, they are enclosed within the chromite grains in association with sulphides. The general sulphide assemblage comprises pentlandite and chalcopyrite whereas, the PGMs assemblage comprises cooperite, ferroplatinum, laurite, FeRhS and PtRhS.
- Full Text:
- Date Issued: 2014
- Authors: Machumele, Nkateko Jones
- Date: 2014
- Subjects: Modikwa Platinum Mine (South Africa) , Chromite -- South Africa -- Limpopo , Geology -- South Africa -- Limpopo , Petrology -- South Africa -- Limpopo , Mineralogy -- South Africa -- Limpopo , Platinum mines and mining -- South Africa -- Limpopo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5074 , http://hdl.handle.net/10962/d1013553
- Description: The UG3 at Modikwa Platinum Mine occurs as a platiniferous, planar chromitite seam. It is stratigraphically located in the Upper Critical Zone of the Eastern Bushveld Complex. Field work study comprise of underground mapping, sampling, surface mapping, borehole core logging, microprobing and microscopic investigations carried out at the Rhodes University. The UG3 at the Modikwa Platinum Mine is about 22cm thick chromitite seam underlain by a white fine grained anorthosite and overlain by a brown medium grained feldspathic pyroxenite. It is an incomplete cyclic unit consisting of chromite and feldspathic pyroxenite. The UG3 reef at the Modikwa Platinum Mine lease area represents a Platinum Group Metal resource of 300 million tons of ore at an in situ grade of 2.5g/t. Under the current market conditions the UG3 reef remains unprofitable to mine in an underground operation due to the operational cost involved. However, it has been illustrated that the UG3 chromitite seam can increase profit margins in an open pit operation provided it is mined together with the economic UG2 chromitite seam. The extraction of the UG3 as ore in the four Modikwa UG2 open pits would result in a combined operating cash profit of R330 million. The UG3 chromitite seam is platiniferous. The platinum-group minerals (PGM) range in size from less than 10μm to about 70μm. The PGMs are associated with sulphides and are both located in the interstitial silicates and are concentrated in the chromitite seam. The PGMs show a strong preference to contact boundaries of the silicate grains, the chromite grains and the sulphide phases. In some instances, they are enclosed within the chromite grains in association with sulphides. The general sulphide assemblage comprises pentlandite and chalcopyrite whereas, the PGMs assemblage comprises cooperite, ferroplatinum, laurite, FeRhS and PtRhS.
- Full Text:
- Date Issued: 2014
A goal-setting intervention with motocross racers : a case study investigating the effects of an intervention on perceived motivation, confidence, and self-efficacy
- Authors: Fleming, Tracey Laura
- Date: 2014
- Subjects: Motocross -- Psychological aspects -- Research , Motorcyclists -- Psychological aspects -- Research , Goal (Psychology) -- Research , Competition (Psychology) -- Research , Motivation (Psychology) -- Case studies , Confidence -- Case studies , Self-efficacy -- Case studies , Sports -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3224 , http://hdl.handle.net/10962/d1012996
- Description: This study aimed to investigate the effects that a specifically tailored goal-setting program would have on two motocross racers in terms of their self-efficacy and motivation, as well as the process of designing this intervention. This case-study approach involved a mixed methods approach, consisting of pre-intervention and post-intervention assessments, interviews, and performance profiles. The tools used include Vealey’s (1986) Competitive Orientation Inventory (COI), Gill and Deeter’s (1988) Sport Orientation Questionnaire (SOQ), performance profiles, and semi-structured interviews. The goal-setting intervention lasted a total of five weeks. The results from the preintervention and post-intervention assessments were compared to determine whether any changes in motivation or self-efficacy occurred during the intervention. For the first participant, significant changes in both motivation and self-efficacy were present in addition to significant changes in competitive orientation. For the second participant, there were no significant changes in either motivation or self-efficacy. However, for the second participant there was also no change in competitive orientation. Findings suggest that the focus and competitive orientation of an athlete have a significant influence on the types of goals set, and consequently on positive changes in motivation, confidence, and self-efficacy. The influence of the competitive orientation in athletes also highlighted the importance of attaining a balance between performance and outcome goal-related activities. It was also discovered through qualitative assessment that this program is suitable for particular groups of athletes such as those who are injured, display an external locus of causality or are otherwise not performing at their prime.
- Full Text:
- Date Issued: 2014
- Authors: Fleming, Tracey Laura
- Date: 2014
- Subjects: Motocross -- Psychological aspects -- Research , Motorcyclists -- Psychological aspects -- Research , Goal (Psychology) -- Research , Competition (Psychology) -- Research , Motivation (Psychology) -- Case studies , Confidence -- Case studies , Self-efficacy -- Case studies , Sports -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3224 , http://hdl.handle.net/10962/d1012996
- Description: This study aimed to investigate the effects that a specifically tailored goal-setting program would have on two motocross racers in terms of their self-efficacy and motivation, as well as the process of designing this intervention. This case-study approach involved a mixed methods approach, consisting of pre-intervention and post-intervention assessments, interviews, and performance profiles. The tools used include Vealey’s (1986) Competitive Orientation Inventory (COI), Gill and Deeter’s (1988) Sport Orientation Questionnaire (SOQ), performance profiles, and semi-structured interviews. The goal-setting intervention lasted a total of five weeks. The results from the preintervention and post-intervention assessments were compared to determine whether any changes in motivation or self-efficacy occurred during the intervention. For the first participant, significant changes in both motivation and self-efficacy were present in addition to significant changes in competitive orientation. For the second participant, there were no significant changes in either motivation or self-efficacy. However, for the second participant there was also no change in competitive orientation. Findings suggest that the focus and competitive orientation of an athlete have a significant influence on the types of goals set, and consequently on positive changes in motivation, confidence, and self-efficacy. The influence of the competitive orientation in athletes also highlighted the importance of attaining a balance between performance and outcome goal-related activities. It was also discovered through qualitative assessment that this program is suitable for particular groups of athletes such as those who are injured, display an external locus of causality or are otherwise not performing at their prime.
- Full Text:
- Date Issued: 2014
A hybrid model for managing personal health records in South Africa
- Authors: Kyazze, Michael
- Date: 2014
- Subjects: Cloud computing -- South Africa , Information storage and retrieval systems -- Medical care -- South Africa , Medical records -- Management -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3145 , vital:20403
- Description: Doctors can experience difficulty in accessing medical information of new patients. One reason for this is that the management of medical records is mostly institution-centred. The lack of access to medical information may negatively affect patients in several ways. These include new medical tests that may need to be carried out at a cost to the patient and doctors prescribing drugs to which the patient is allergic. This research investigates how patients can play an active role in sharing their personal health records (PHRs) with doctors located in geographically separate areas. In order to achieve the goal of this research, existing literature concerning medical health records and standards was reviewed. A literature review of techniques that can be used to ensure privacy of health information was also undertaken. Interview studies were carried out with three medical practices in Port Elizabeth with the aim of contextualising the findings from the literature study. The Design Science Research methodology was used for this research. A Hybrid Model for Managing Personal Health Records in South Africa is proposed. This model allows patients to view their PHRs on their mobile phones and medical practitioners to manage the patients’ PHRs using a web-based application. The patients’ PHR information is stored both on a cloud server and on mobile devices hence the hybrid nature. Two prototypes were developed as a proof of concept; a mobile application for the patients and a web-based application for the medical practitioners. A field study was carried out with the NMMU health services department and 12 participants over a period of two weeks. The results of the field study were highly positive. The successful evaluation of the prototypes provides empirical evidence that the proposed model brings us closer to the realisation of ubiquitous access to PHRS in South Africa.
- Full Text:
- Date Issued: 2014
- Authors: Kyazze, Michael
- Date: 2014
- Subjects: Cloud computing -- South Africa , Information storage and retrieval systems -- Medical care -- South Africa , Medical records -- Management -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3145 , vital:20403
- Description: Doctors can experience difficulty in accessing medical information of new patients. One reason for this is that the management of medical records is mostly institution-centred. The lack of access to medical information may negatively affect patients in several ways. These include new medical tests that may need to be carried out at a cost to the patient and doctors prescribing drugs to which the patient is allergic. This research investigates how patients can play an active role in sharing their personal health records (PHRs) with doctors located in geographically separate areas. In order to achieve the goal of this research, existing literature concerning medical health records and standards was reviewed. A literature review of techniques that can be used to ensure privacy of health information was also undertaken. Interview studies were carried out with three medical practices in Port Elizabeth with the aim of contextualising the findings from the literature study. The Design Science Research methodology was used for this research. A Hybrid Model for Managing Personal Health Records in South Africa is proposed. This model allows patients to view their PHRs on their mobile phones and medical practitioners to manage the patients’ PHRs using a web-based application. The patients’ PHR information is stored both on a cloud server and on mobile devices hence the hybrid nature. Two prototypes were developed as a proof of concept; a mobile application for the patients and a web-based application for the medical practitioners. A field study was carried out with the NMMU health services department and 12 participants over a period of two weeks. The results of the field study were highly positive. The successful evaluation of the prototypes provides empirical evidence that the proposed model brings us closer to the realisation of ubiquitous access to PHRS in South Africa.
- Full Text:
- Date Issued: 2014
A hybridisation technique for game playing using the upper confidence for trees algorithm with artificial neural networks
- Authors: Burger, Clayton
- Date: 2014
- Subjects: Neural networks (Computer science) , Computer algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3957 , vital:20495
- Description: In the domain of strategic game playing, the use of statistical techniques such as the Upper Confidence for Trees (UCT) algorithm, has become the norm as they offer many benefits over classical algorithms. These benefits include requiring no game-specific strategic knowledge and time-scalable performance. UCT does not incorporate any strategic information specific to the game considered, but instead uses repeated sampling to effectively brute-force search through the game tree or search space. The lack of game-specific knowledge in UCT is thus both a benefit but also a strategic disadvantage. Pattern recognition techniques, specifically Neural Networks (NN), were identified as a means of addressing the lack of game-specific knowledge in UCT. Through a novel hybridisation technique which combines UCT and trained NNs for pruning, the UCTNN algorithm was derived. The NN component of UCT-NN was trained using a UCT self-play scheme to generate game-specific knowledge without the need to construct and manage game databases for training purposes. The UCT-NN algorithm is outlined for pruning in the game of Go-Moku as a candidate case-study for this research. The UCT-NN algorithm contained three major parameters which emerged from the UCT algorithm, the use of NNs and the pruning schemes considered. Suitable methods for finding candidate values for these three parameters were outlined and applied to the game of Go-Moku on a 5 by 5 board. An empirical investigation of the playing performance of UCT-NN was conducted in comparison to UCT through three benchmarks. The benchmarks comprise a common randomly moving opponent, a common UCTmax player which is given a large amount of playing time, and a pair-wise tournament between UCT-NN and UCT. The results of the performance evaluation for 5 by 5 Go-Moku were promising, which prompted an evaluation of a larger 9 by 9 Go-Moku board. The results of both evaluations indicate that the time allocated to the UCT-NN algorithm directly affects its performance when compared to UCT. The UCT-NN algorithm generally performs better than UCT in games with very limited time-constraints in all benchmarks considered except when playing against a randomly moving player in 9 by 9 Go-Moku. In real-time and near-real-time Go-Moku games, UCT-NN provides statistically significant improvements compared to UCT. The findings of this research contribute to the realisation of applying game-specific knowledge to the UCT algorithm.
- Full Text:
- Date Issued: 2014
- Authors: Burger, Clayton
- Date: 2014
- Subjects: Neural networks (Computer science) , Computer algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3957 , vital:20495
- Description: In the domain of strategic game playing, the use of statistical techniques such as the Upper Confidence for Trees (UCT) algorithm, has become the norm as they offer many benefits over classical algorithms. These benefits include requiring no game-specific strategic knowledge and time-scalable performance. UCT does not incorporate any strategic information specific to the game considered, but instead uses repeated sampling to effectively brute-force search through the game tree or search space. The lack of game-specific knowledge in UCT is thus both a benefit but also a strategic disadvantage. Pattern recognition techniques, specifically Neural Networks (NN), were identified as a means of addressing the lack of game-specific knowledge in UCT. Through a novel hybridisation technique which combines UCT and trained NNs for pruning, the UCTNN algorithm was derived. The NN component of UCT-NN was trained using a UCT self-play scheme to generate game-specific knowledge without the need to construct and manage game databases for training purposes. The UCT-NN algorithm is outlined for pruning in the game of Go-Moku as a candidate case-study for this research. The UCT-NN algorithm contained three major parameters which emerged from the UCT algorithm, the use of NNs and the pruning schemes considered. Suitable methods for finding candidate values for these three parameters were outlined and applied to the game of Go-Moku on a 5 by 5 board. An empirical investigation of the playing performance of UCT-NN was conducted in comparison to UCT through three benchmarks. The benchmarks comprise a common randomly moving opponent, a common UCTmax player which is given a large amount of playing time, and a pair-wise tournament between UCT-NN and UCT. The results of the performance evaluation for 5 by 5 Go-Moku were promising, which prompted an evaluation of a larger 9 by 9 Go-Moku board. The results of both evaluations indicate that the time allocated to the UCT-NN algorithm directly affects its performance when compared to UCT. The UCT-NN algorithm generally performs better than UCT in games with very limited time-constraints in all benchmarks considered except when playing against a randomly moving player in 9 by 9 Go-Moku. In real-time and near-real-time Go-Moku games, UCT-NN provides statistically significant improvements compared to UCT. The findings of this research contribute to the realisation of applying game-specific knowledge to the UCT algorithm.
- Full Text:
- Date Issued: 2014
A lignocellulolytic enzyme system for fruit waste degradation : commercial enzyme mixture synergy and bioreactor design
- Authors: Gama, Repson
- Date: 2014
- Subjects: Enzymes -- Biotechnology , Enzymes -- Industrial applications , Lignocellulose -- Biodegradation , Biomass energy , Biomass conversion , Biochemical engineering , Agricultural wastes as fuel
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4114 , http://hdl.handle.net/10962/d1013073
- Description: Studies into sources of alternative liquid transport fuel energy have identified agro-industrial wastes, which are lignocellulosic in nature, as a potential feedstock for biofuel production against the background of depleting nonrenewable fossil fuels. In South Africa, large quantities of apple and other fruit wastes, called pomace, are generated from fruit and juice industries. Apple pomace is a rich source of cellulose, pectin and hemicellulose, making it a potential target for utilisation as a lignocellulosic feedstock for biofuel and biorefinery chemical production. Lignocellulosic biomass is recalcitrant in nature and therefore its degradation requires the synergistic action of a number of enzymes such as cellulases, hemicellulases, pectinases and ligninases. Commercial enzyme cocktails, containing some of these enzymes, are available and can be used for apple pomace degradation. In this study, the degradation of apple pomace using commercial enzyme cocktails was investigated. The main focus was the optimisation of the release of sugar monomers that could potentially be used for biofuel and biorefinery chemical production. There is no or little information reported in literature on the enzymatic degradation of fruit waste using commercial enzyme mixtures. This study first focused on the characterisation of the substrate (apple pomace) and the commercial enzyme cocktails. Apple pomace was found to contain mainly glucose, galacturonic acid, arabinose, galactose, lignin and low amounts of xylose and fructose. Three commercial enzyme cocktails were initially selected: Biocip Membrane, Viscozyme L (from Aspergillus aculeatus) and Celluclast 1.5L (a Trichoderma reesei ATCC 26921 cellulase preparation). The selection of the enzymes was based on activities declared by the manufacturers, cost and local availability. The enzymes were screened based on their synergistic cooperation in the degradation of apple pomace and the main enzymes present in each cocktail. Viscozyme L and Celluclast 1.5L, in a 50:50 ratio, resulted in the best degree of synergy (1.6) compared to any other combination. The enzyme ratios were determined on Viscozyme L and Celluclast 1.5L based on the protein ratio. Enzyme activity was determined as glucose equivalents using the dinitrosalicylic acid (DNS) method. Sugar monomers were determined using Megazyme assay kits. There is limited information available on the enzymes present in the commercial enzyme cocktails. Therefore, the main enzymes present in Viscozyme L and Celluclast 1.5L were identified using different substrates, each targeted for a specific enzyme and activity. Characterisation of the enzyme mixtures revealed a large number of enzymes required for apple pomace degradation and these included cellulases, pectinases, xylanases, arabinases and mannanases in different proportions. Viscozyme L contained mainly pectinases and hemicellulases, while Celluclast 1.5L displayed largely cellulase and xylanase activity, hence the high degree of synergy reported. The temperature optimum was 50ºC for both enzyme mixtures and pH optima were observed at pH 5.0 and pH 3.0 for Viscozyme L and Celluclast 1.5L, respectively. At 37ºC and pH 5.0, the enzymes retained more that 90% activity after 15 days of incubation, allowing the enzymes to be used together with less energy input. The enzymes were further characterised by determining the effect of various compounds, such as alcohols, sugars, phenolic compounds and metal ions at various concentrations on the activity of the enzymes during apple pomace hydrolysis. Apart from lignin, which had almost no effect on enzyme activity, all the compounds caused inhibition of the enzymes to varying degrees. The most inhibitory compounds were some organic acids and metal ions, as well as cellobiose and xylobiose. Using the best ratio for Viscozyme L and Celluclast 1.5L (50:50) for the hydrolysis of apple pomace, it was observed that synergy was highest at the initial stages of hydrolysis and decreased over time, though the sugar concentration increased. The type of synergy for optimal apple pomace hydrolysis was found to be simultaneous. There was no synergy observed between Viscozyme L and Celluclast 1.5L with ligninases - laccase, lignin peroxidase and manganese peroxidase. Hydrolysing apple pomace with ligninases prior to addition of Viscozyme L and Celluclast 1.5L did not improve degradation of the substrate. Immobilisation of the enzyme mixtures on different supports was performed with the aim of increasing stability and enabling reuse of the enzymes. Immobilisation methods were selected based on the chemical properties of the supports, availability, cost and applicability on heterogeneous and insoluble substrate like apple pomace. These methods included crosslinked enzyme aggregates (CLEAs), immobilisation on various supports such as nylon mesh, nylon beads, sodium alginate beads, chitin and silica gel beads. The immobilisation strategies were unsuccessful, mainly due to the low percentage of immobilisation of the enzyme on the matrix and loss of activity of the immobilised enzyme. Free enzymes were therefore used for the remainder of the study. Hydrolysis conditions for apple pomace degradation were optimised using different temperatures and buffer systems in 1 L volumes mixed with compressed air. Hydrolysis at room temperature, using an unbuffered system, gave a better performance as compared to a buffered system. Reactors operated in batch mode performed better (4.2 g/L (75% yield) glucose and 16.8 g/L (75%) reducing sugar) than fed-batch reactors (3.2 g/L (66%) glucose and 14.6 g/L (72.7% yield) reducing sugar) over 100 h using Viscozyme L and Celluclast 1.5L. Supplementation of β- glucosidase activity in Viscozyme L and Celluclast 1.5L with Novozyme 188 resulted in a doubling of the amount of glucose released. The main products released from apple pomace hydrolysis were galacturonic acid, glucose and arabinose and low amounts of galactose and xylose. These products are potential raw materials for biofuel and biorefinery chemical production. An artificial neural network (ANN) model was successfully developed and used for predicting the optimum conditions for apple pomace hydrolysis using Celluclast 1.5L, Viscozyme L and Novozyme 188. Four main conditions that affect apple pomace hydrolysis were selected, namely temperature, initial pH, enzyme loading and substrate loading, which were taken as inputs. The glucose and reducing sugars released as a result of each treatment and their combinations were taken as outputs for 1–100 h. An ANN with 20, 20 and 6 neurons in the first, second and third hidden layers, respectively, was constructed. The performance and predictive ability of the ANN was good, with a R² of 0.99 and a small mean square error (MSE). New data was successfully predicted and simulated. Optimal hydrolysis conditions predicted by ANN for apple pomace hydrolysis were at 30% substrate (wet w/v) and an enzyme loading of 0.5 mg/g and 0.2 mg/mL of substrate for glucose and reducing sugar, respectively, giving sugar concentrations of 6.5 mg/mL and 28.9 mg/mL for glucose and reducing sugar, respectively. ANN showed that enzyme and substrate loadings were the most important factors for the hydrolysis of apple pomace.
- Full Text:
- Date Issued: 2014
- Authors: Gama, Repson
- Date: 2014
- Subjects: Enzymes -- Biotechnology , Enzymes -- Industrial applications , Lignocellulose -- Biodegradation , Biomass energy , Biomass conversion , Biochemical engineering , Agricultural wastes as fuel
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4114 , http://hdl.handle.net/10962/d1013073
- Description: Studies into sources of alternative liquid transport fuel energy have identified agro-industrial wastes, which are lignocellulosic in nature, as a potential feedstock for biofuel production against the background of depleting nonrenewable fossil fuels. In South Africa, large quantities of apple and other fruit wastes, called pomace, are generated from fruit and juice industries. Apple pomace is a rich source of cellulose, pectin and hemicellulose, making it a potential target for utilisation as a lignocellulosic feedstock for biofuel and biorefinery chemical production. Lignocellulosic biomass is recalcitrant in nature and therefore its degradation requires the synergistic action of a number of enzymes such as cellulases, hemicellulases, pectinases and ligninases. Commercial enzyme cocktails, containing some of these enzymes, are available and can be used for apple pomace degradation. In this study, the degradation of apple pomace using commercial enzyme cocktails was investigated. The main focus was the optimisation of the release of sugar monomers that could potentially be used for biofuel and biorefinery chemical production. There is no or little information reported in literature on the enzymatic degradation of fruit waste using commercial enzyme mixtures. This study first focused on the characterisation of the substrate (apple pomace) and the commercial enzyme cocktails. Apple pomace was found to contain mainly glucose, galacturonic acid, arabinose, galactose, lignin and low amounts of xylose and fructose. Three commercial enzyme cocktails were initially selected: Biocip Membrane, Viscozyme L (from Aspergillus aculeatus) and Celluclast 1.5L (a Trichoderma reesei ATCC 26921 cellulase preparation). The selection of the enzymes was based on activities declared by the manufacturers, cost and local availability. The enzymes were screened based on their synergistic cooperation in the degradation of apple pomace and the main enzymes present in each cocktail. Viscozyme L and Celluclast 1.5L, in a 50:50 ratio, resulted in the best degree of synergy (1.6) compared to any other combination. The enzyme ratios were determined on Viscozyme L and Celluclast 1.5L based on the protein ratio. Enzyme activity was determined as glucose equivalents using the dinitrosalicylic acid (DNS) method. Sugar monomers were determined using Megazyme assay kits. There is limited information available on the enzymes present in the commercial enzyme cocktails. Therefore, the main enzymes present in Viscozyme L and Celluclast 1.5L were identified using different substrates, each targeted for a specific enzyme and activity. Characterisation of the enzyme mixtures revealed a large number of enzymes required for apple pomace degradation and these included cellulases, pectinases, xylanases, arabinases and mannanases in different proportions. Viscozyme L contained mainly pectinases and hemicellulases, while Celluclast 1.5L displayed largely cellulase and xylanase activity, hence the high degree of synergy reported. The temperature optimum was 50ºC for both enzyme mixtures and pH optima were observed at pH 5.0 and pH 3.0 for Viscozyme L and Celluclast 1.5L, respectively. At 37ºC and pH 5.0, the enzymes retained more that 90% activity after 15 days of incubation, allowing the enzymes to be used together with less energy input. The enzymes were further characterised by determining the effect of various compounds, such as alcohols, sugars, phenolic compounds and metal ions at various concentrations on the activity of the enzymes during apple pomace hydrolysis. Apart from lignin, which had almost no effect on enzyme activity, all the compounds caused inhibition of the enzymes to varying degrees. The most inhibitory compounds were some organic acids and metal ions, as well as cellobiose and xylobiose. Using the best ratio for Viscozyme L and Celluclast 1.5L (50:50) for the hydrolysis of apple pomace, it was observed that synergy was highest at the initial stages of hydrolysis and decreased over time, though the sugar concentration increased. The type of synergy for optimal apple pomace hydrolysis was found to be simultaneous. There was no synergy observed between Viscozyme L and Celluclast 1.5L with ligninases - laccase, lignin peroxidase and manganese peroxidase. Hydrolysing apple pomace with ligninases prior to addition of Viscozyme L and Celluclast 1.5L did not improve degradation of the substrate. Immobilisation of the enzyme mixtures on different supports was performed with the aim of increasing stability and enabling reuse of the enzymes. Immobilisation methods were selected based on the chemical properties of the supports, availability, cost and applicability on heterogeneous and insoluble substrate like apple pomace. These methods included crosslinked enzyme aggregates (CLEAs), immobilisation on various supports such as nylon mesh, nylon beads, sodium alginate beads, chitin and silica gel beads. The immobilisation strategies were unsuccessful, mainly due to the low percentage of immobilisation of the enzyme on the matrix and loss of activity of the immobilised enzyme. Free enzymes were therefore used for the remainder of the study. Hydrolysis conditions for apple pomace degradation were optimised using different temperatures and buffer systems in 1 L volumes mixed with compressed air. Hydrolysis at room temperature, using an unbuffered system, gave a better performance as compared to a buffered system. Reactors operated in batch mode performed better (4.2 g/L (75% yield) glucose and 16.8 g/L (75%) reducing sugar) than fed-batch reactors (3.2 g/L (66%) glucose and 14.6 g/L (72.7% yield) reducing sugar) over 100 h using Viscozyme L and Celluclast 1.5L. Supplementation of β- glucosidase activity in Viscozyme L and Celluclast 1.5L with Novozyme 188 resulted in a doubling of the amount of glucose released. The main products released from apple pomace hydrolysis were galacturonic acid, glucose and arabinose and low amounts of galactose and xylose. These products are potential raw materials for biofuel and biorefinery chemical production. An artificial neural network (ANN) model was successfully developed and used for predicting the optimum conditions for apple pomace hydrolysis using Celluclast 1.5L, Viscozyme L and Novozyme 188. Four main conditions that affect apple pomace hydrolysis were selected, namely temperature, initial pH, enzyme loading and substrate loading, which were taken as inputs. The glucose and reducing sugars released as a result of each treatment and their combinations were taken as outputs for 1–100 h. An ANN with 20, 20 and 6 neurons in the first, second and third hidden layers, respectively, was constructed. The performance and predictive ability of the ANN was good, with a R² of 0.99 and a small mean square error (MSE). New data was successfully predicted and simulated. Optimal hydrolysis conditions predicted by ANN for apple pomace hydrolysis were at 30% substrate (wet w/v) and an enzyme loading of 0.5 mg/g and 0.2 mg/mL of substrate for glucose and reducing sugar, respectively, giving sugar concentrations of 6.5 mg/mL and 28.9 mg/mL for glucose and reducing sugar, respectively. ANN showed that enzyme and substrate loadings were the most important factors for the hydrolysis of apple pomace.
- Full Text:
- Date Issued: 2014
A mathematics rendering model to support chat-based tutoring
- Authors: Haskins, Bertram Peter
- Date: 2014
- Subjects: Intelligent tutoring systems , Educational innovations , Tutors and tutoring
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9822 , http://hdl.handle.net/10948/d1020567
- Description: Dr Math is a math tutoring service implemented on the chat application Mxit. The service allows school learners to use their mobile phones to discuss mathematicsrelated topics with human tutors. Using the broad user-base provided by Mxit, the Dr Math service has grown to consist of tens of thousands of registered school learners. The tutors on the service are all volunteers and the learners far outnumber the available tutors at any given time. School learners on the service use a shorthand language-form called microtext, to phrase their queries. Microtext is an informal form of language which consists of a variety of misspellings and symbolic representations, which emerge spontaneously as a result of the idiosyncrasies of a learner. The specific form of microtext found on the Dr Math service contains mathematical questions and example equations, pertaining to the tutoring process. Deciphering the queries, to discover their embedded mathematical content, slows down the tutoring process. This wastes time that could have been spent addressing more learner queries. The microtext language thus creates an unnecessary burden on the tutors. This study describes the development of an automated process for the translation of Dr Math microtext queries into mathematical equations. Using the design science research paradigm as a guide, three artefacts are developed. These artefacts take the form of a construct, a model and an instantiation. The construct represents the creation of new knowledge as it provides greater insight into the contents and structure of the language found on a mobile mathematics tutoring service. The construct serves as the basis for the creation of a model for the translation of microtext queries into mathematical equations, formatted for display in an electronic medium. No such technique currently exists and therefore, the model contributes new knowledge. To validate the model, an instantiation was created to serve as a proof-of-concept. The instantiation applies various concepts and techniques, such as those related to natural language processing, to the learner queries on the Dr Math service. These techniques are employed in order to translate an input microtext statement into a mathematical equation, structured by using mark-up language. The creation of the instantiation thus constitutes a knowledge contribution, as most of these techniques have never been applied to the problem of translating microtext into mathematical equations. For the automated process to have utility, it should perform on a level comparable to that of a human performing a similar translation task. To determine how closely related the results from the automated process are to those of a human, three human participants were asked to perform coding and translation tasks. The results of the human participants were compared to the results of the automated process, across a variety of metrics, including agreement, correlation, precision, recall and others. The results from the human participants served as the baseline values for comparison. The baseline results from the human participants were compared with those of the automated process. Krippendorff’s α was used to determine the level of agreement and Pearson’s correlation coefficient to determine the level of correlation between the results. The agreement between the human participants and the automated process was calculated at a level deemed satisfactory for exploratory research and the level of correlation was calculated as moderate. These values correspond with the calculations made as the human baseline. Furthermore, the automated process was able to meet or improve on all of the human baseline metrics. These results serve to validate that the automated process is able to perform the translation at a level comparable to that of a human. The automated process is available for integration into any requesting application, by means of a publicly accessible web service.
- Full Text:
- Date Issued: 2014
- Authors: Haskins, Bertram Peter
- Date: 2014
- Subjects: Intelligent tutoring systems , Educational innovations , Tutors and tutoring
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9822 , http://hdl.handle.net/10948/d1020567
- Description: Dr Math is a math tutoring service implemented on the chat application Mxit. The service allows school learners to use their mobile phones to discuss mathematicsrelated topics with human tutors. Using the broad user-base provided by Mxit, the Dr Math service has grown to consist of tens of thousands of registered school learners. The tutors on the service are all volunteers and the learners far outnumber the available tutors at any given time. School learners on the service use a shorthand language-form called microtext, to phrase their queries. Microtext is an informal form of language which consists of a variety of misspellings and symbolic representations, which emerge spontaneously as a result of the idiosyncrasies of a learner. The specific form of microtext found on the Dr Math service contains mathematical questions and example equations, pertaining to the tutoring process. Deciphering the queries, to discover their embedded mathematical content, slows down the tutoring process. This wastes time that could have been spent addressing more learner queries. The microtext language thus creates an unnecessary burden on the tutors. This study describes the development of an automated process for the translation of Dr Math microtext queries into mathematical equations. Using the design science research paradigm as a guide, three artefacts are developed. These artefacts take the form of a construct, a model and an instantiation. The construct represents the creation of new knowledge as it provides greater insight into the contents and structure of the language found on a mobile mathematics tutoring service. The construct serves as the basis for the creation of a model for the translation of microtext queries into mathematical equations, formatted for display in an electronic medium. No such technique currently exists and therefore, the model contributes new knowledge. To validate the model, an instantiation was created to serve as a proof-of-concept. The instantiation applies various concepts and techniques, such as those related to natural language processing, to the learner queries on the Dr Math service. These techniques are employed in order to translate an input microtext statement into a mathematical equation, structured by using mark-up language. The creation of the instantiation thus constitutes a knowledge contribution, as most of these techniques have never been applied to the problem of translating microtext into mathematical equations. For the automated process to have utility, it should perform on a level comparable to that of a human performing a similar translation task. To determine how closely related the results from the automated process are to those of a human, three human participants were asked to perform coding and translation tasks. The results of the human participants were compared to the results of the automated process, across a variety of metrics, including agreement, correlation, precision, recall and others. The results from the human participants served as the baseline values for comparison. The baseline results from the human participants were compared with those of the automated process. Krippendorff’s α was used to determine the level of agreement and Pearson’s correlation coefficient to determine the level of correlation between the results. The agreement between the human participants and the automated process was calculated at a level deemed satisfactory for exploratory research and the level of correlation was calculated as moderate. These values correspond with the calculations made as the human baseline. Furthermore, the automated process was able to meet or improve on all of the human baseline metrics. These results serve to validate that the automated process is able to perform the translation at a level comparable to that of a human. The automated process is available for integration into any requesting application, by means of a publicly accessible web service.
- Full Text:
- Date Issued: 2014
A method for the evaluation of similarity measures on graphs and network-structured data
- Authors: Naude, Kevin Alexander
- Date: 2014
- Subjects: Graph theory , Network analysis (Planning)
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10494
- Description: Measures of similarity play a subtle but important role in a large number of disciplines. For example, a researcher in bioinformatics may devise a new computed measure of similarity between biological structures, and use its scores to infer bio-logical association. Other academics may use related approaches in structured text search, or for object recognition in computer vision. These are diverse and practical applications of similarity. A critical question is this: to what extent can a given similarity measure be trusted? This is a difficult problem, at the heart of which lies the broader issue: what exactly constitutes good similarity judgement? This research presents the view that similarity measures have properties of judgement that are intrinsic to their formulation, and that such properties are measurable. The problem of comparing similarity measures is one of identifying ground-truths for similarity. The approach taken in this work is to examine the relative ordering of graph pairs, when compared with respect to a common reference graph. Ground- truth outcomes are obtained from a novel theory: the theory of irreducible change in graphs. This theory supports stronger claims than those made for edit distances. Whereas edit distances are sensitive to a configuration of costs, irreducible change under the new theory is independent of such parameters. Ground-truth data is obtained by isolating test cases for which a common outcome is assured for all possible least measures of change that can be formulated within a chosen change descriptor space. By isolating these specific cases, and excluding others, the research introduces a framework for evaluating similarity measures on mathematically defensible grounds. The evaluation method is demonstrated in a series of case studies which evaluate the similarity performance of known graph similarity measures. The findings of these experiments provide the first general characterisation of common similarity measures over a wide range of graph properties. The similarity computed from the maximum common induced subgraph (Dice-MCIS) is shown to provide good general similarity judgement. However, it is shown that Blondel's similarity measure can exceed the judgement sensitivity of Dice-MCIS, provided the graphs have both sufficient attribute label diversity, and edge density. The final contribution is the introduction of a new similarity measure for graphs, which is shown to have statistically greater judgement sensitivity than all other measures examined. All of these findings are made possible through the theory of irreducible change in graphs. The research provides the first mathematical basis for reasoning about the quality of similarity judgments. This enables researchers to analyse similarity measures directly, making similarity measures first class objects of scientific inquiry.
- Full Text:
- Date Issued: 2014
- Authors: Naude, Kevin Alexander
- Date: 2014
- Subjects: Graph theory , Network analysis (Planning)
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10494
- Description: Measures of similarity play a subtle but important role in a large number of disciplines. For example, a researcher in bioinformatics may devise a new computed measure of similarity between biological structures, and use its scores to infer bio-logical association. Other academics may use related approaches in structured text search, or for object recognition in computer vision. These are diverse and practical applications of similarity. A critical question is this: to what extent can a given similarity measure be trusted? This is a difficult problem, at the heart of which lies the broader issue: what exactly constitutes good similarity judgement? This research presents the view that similarity measures have properties of judgement that are intrinsic to their formulation, and that such properties are measurable. The problem of comparing similarity measures is one of identifying ground-truths for similarity. The approach taken in this work is to examine the relative ordering of graph pairs, when compared with respect to a common reference graph. Ground- truth outcomes are obtained from a novel theory: the theory of irreducible change in graphs. This theory supports stronger claims than those made for edit distances. Whereas edit distances are sensitive to a configuration of costs, irreducible change under the new theory is independent of such parameters. Ground-truth data is obtained by isolating test cases for which a common outcome is assured for all possible least measures of change that can be formulated within a chosen change descriptor space. By isolating these specific cases, and excluding others, the research introduces a framework for evaluating similarity measures on mathematically defensible grounds. The evaluation method is demonstrated in a series of case studies which evaluate the similarity performance of known graph similarity measures. The findings of these experiments provide the first general characterisation of common similarity measures over a wide range of graph properties. The similarity computed from the maximum common induced subgraph (Dice-MCIS) is shown to provide good general similarity judgement. However, it is shown that Blondel's similarity measure can exceed the judgement sensitivity of Dice-MCIS, provided the graphs have both sufficient attribute label diversity, and edge density. The final contribution is the introduction of a new similarity measure for graphs, which is shown to have statistically greater judgement sensitivity than all other measures examined. All of these findings are made possible through the theory of irreducible change in graphs. The research provides the first mathematical basis for reasoning about the quality of similarity judgments. This enables researchers to analyse similarity measures directly, making similarity measures first class objects of scientific inquiry.
- Full Text:
- Date Issued: 2014
A mobile phone solution for ad-hoc hitch-hiking in South Africa
- Authors: Miteche, Sacha Patrick
- Date: 2014
- Subjects: Cell phones -- Information services , Cell phone users -- South Africa , Hitchhiking -- South Africa , Mobile communication systems -- Social aspects , Digital media -- South Africa , Information technology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4702 , http://hdl.handle.net/10962/d1013340
- Description: The purpose of this study was to investigate the use of mobile phones in organizing ad-hoc vehicle ridesharing based on hitch-hiking trips involving private car drivers and commuters in South Africa. A study was conducted to learn how hitch-hiking trips are arranged in the urban and rural areas of the Eastern Cape. This involved carrying out interviews with hitch-hikers and participating in several trips. The study results provided the design specifications for a Dynamic Ridesharing System (DRS) tailor-made to the hitch-hiking culture of this context. The design of the DRS considered the delivery of the ad-hoc ridesharing service to the anticipated mobile phones owned by people who use hitch-hiking. The implementation of the system used the available open source solutions and guidelines under the Siyakhula Living Lab project, which promotes the use of Information and Communication Technology (ICT) in marginalized communities of South Africa. The developed prototype was tested in both the simulated and live environments, then followed by usability tests to establish the viability of the system. The results from the tests indicate an initial breakthrough in the process of modernizing the ad-hoc ridesharing of hitch-hiking which is used by a section of people in the urban and rural areas of South Africa.
- Full Text:
- Date Issued: 2014
- Authors: Miteche, Sacha Patrick
- Date: 2014
- Subjects: Cell phones -- Information services , Cell phone users -- South Africa , Hitchhiking -- South Africa , Mobile communication systems -- Social aspects , Digital media -- South Africa , Information technology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4702 , http://hdl.handle.net/10962/d1013340
- Description: The purpose of this study was to investigate the use of mobile phones in organizing ad-hoc vehicle ridesharing based on hitch-hiking trips involving private car drivers and commuters in South Africa. A study was conducted to learn how hitch-hiking trips are arranged in the urban and rural areas of the Eastern Cape. This involved carrying out interviews with hitch-hikers and participating in several trips. The study results provided the design specifications for a Dynamic Ridesharing System (DRS) tailor-made to the hitch-hiking culture of this context. The design of the DRS considered the delivery of the ad-hoc ridesharing service to the anticipated mobile phones owned by people who use hitch-hiking. The implementation of the system used the available open source solutions and guidelines under the Siyakhula Living Lab project, which promotes the use of Information and Communication Technology (ICT) in marginalized communities of South Africa. The developed prototype was tested in both the simulated and live environments, then followed by usability tests to establish the viability of the system. The results from the tests indicate an initial breakthrough in the process of modernizing the ad-hoc ridesharing of hitch-hiking which is used by a section of people in the urban and rural areas of South Africa.
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- Date Issued: 2014