Herman Vermaak - Academia.edu (original) (raw)

Papers by Herman Vermaak

Recently, a new type of Design-for-Delay-Testability (DfDT) structure and associated Built-In Sel... more Recently, a new type of Design-for-Delay-Testability (DfDT) structure and associated Built-In Self-Test architecture for detecting delay faults in digital highperformance circuits has been proposed. It circumvents the requirement of an expensive high-speed tester. In this paper, the ability of the proposed structure to function correctly in an environment with process- and application-induced variations has been investigated. Practical solutions to ensure proper operation of the DfDT structure will be proposed and verified by means of simulation. Due to the critical timing necessary when detecting small delay faults it is crucial to know what to expect from these variations and subsequently reduce their influence.

Recently, a new type of Design-for-Delay-Testability (DfDT) structure and associated Built-In Sel... more Recently, a new type of Design-for-Delay-Testability (DfDT) structure and associated Built-In Self-Test architecture for detecting delay faults in digital high-performance circuits has been proposed. It circumvents the requirement of an expensive high-speed tester. In this paper, the ability of the proposed structure to function correctly in an environment with process-and application-induced variations has been investigated. Practical solutions to ensure proper operation of the DfDT structure will be proposed and verified by means of simulation. Due to the critical timing necessary when detecting small delay faults it is crucial to know what to expect from these variations and subsequently reduce their influence.

Continual advances in the manufacturing processes of integrated circuits provide designers the ab... more Continual advances in the manufacturing processes of integrated circuits provide designers the ability to create more complex and denser architectures and increased functionality on a single chip. The increased usage of embedded cores necessitates a core-based test strategy in which cores are also tested separately. The IEEE P1500 proposed standard for Embedded Core Test (SECT) is a standard under development which aim is to improve the testing of core-based system chips. This paper deals with the enhancement of the Test Wrapper and Wrapper Cells to provide a structure to be able to test embedded cores for delay faults. This approach allows delay fault testing of cores by using the digital oscillation test method and the help of the enhanced elements while staying compliant to the P1500 standard.

This paper describes the possible implementation of an experimental three-dimensional photographi... more This paper describes the possible implementation of an experimental three-dimensional photographic system incorporating an unsophisticated laser scanning system and the results attained with such. Its use in determining the dimensional characteristics of components being transported on a conveyor system in an automated material-handling facility, as well as the transformation of its output into a file for rapid prototyping purposes is considered. A critical assessment of the operational characteristics of the system is presented.

Renewable Energy in the Service of Mankind Vol I, 2015

Standalone micro-hydrokinetic river (MHR) system is one of the promising technologies to be used ... more Standalone micro-hydrokinetic river (MHR) system is one of the promising technologies to be used for remote rural electrification. It simply requires the flow of water instead of elevation or head, leading to expensive civil works. This paper demonstrates an economic benefit offered by a standalone MHR system when compared to the commonly used standalone systems such as solar, wind and diesel generator (DG) at the selected study site in Kwazulu Natal. Wind speed and solar radiation data of the selected rural site have been taken from national aeronautics and space administration (NASA) surface meteorology database. The hybrid optimization model for electric renewable (HOMER) software was used to determine the most feasible solution when using MHR, solar, wind or DG system to supply 5 rural houses. MHR system proved to be the best cost-effective option to consider at the study site due to its low cost of energy (COE) and low net present cost (NPC).

One of the major challenges facing the growth of South Africa, the largest economy in Africa and ... more One of the major challenges facing the growth of South Africa, the largest economy in Africa and a member of the five major emerging national economies (BRICS) of the world, is unemployment. While there are other factors influencing unemployment, high dropout rates in universities are seen as a definite contributor to this challenge. Reflection and reflective practices have been extensively researched over the years by Richert, Moon and Green to name a few. The research question that arises that this paper attempts to address is what academics can do to reduce the high dropout rates of students in tertiary institution. The paper presents an effective teaching technique using the centric reflection model and the Greenaway’s model. The paper firstly looks at the actual causes behind the failures at first year level such as high student volume, language barrier and poor motivation. Secondly it details how a model was created using centric reflection model which addresses these causes a...

2010 IEEE International Symposium on Industrial Electronics, 2010

Automatic Guided Vehicles (AGV) are being used more frequently in a manufacturing environment. De... more Automatic Guided Vehicles (AGV) are being used more frequently in a manufacturing environment. Developing a platform that could be easily reconfigured is perhaps a more desirable option for a user with low capacity outputs. This research concentrates on an AGV and the development of the actuators and sensors, as well as the mounting of such for navigation and functionality, on such a vehicle.

Electric Power Systems Research, 2015

Micro-hydrokinetic river (MHR) system is one of the promising technologies to be used for remote ... more Micro-hydrokinetic river (MHR) system is one of the promising technologies to be used for remote rural electrification. In rural areas with access to both wind and flowing water resources, wind generation is selected as a first electrification priority. The potential benefit of generating electricity using flowing water resource is unnoticed. Hence, this paper presents the modelling and performance analysis of a MHR system as compared to wind generation system using MATLAB/Simulink software. These performances are compared to generate the same amount of electrical power. A permanent magnet synchronous generator (PMSG) has been chosen or used to investigate the behaviour of each system under variable speeds. The developed model includes horizontal turbine model, drive train model and PMSG model. The simulation results illustrate the ability of a hydrokinetic turbine driven PMSG to generate electricity markedly better and cheaper than a wind driven PMSG within South Africa. Hence, the MHR system presents a cheap electrification opportunity for poor rural households.

2013 6th Robotics and Mechatronics Conference (RobMech), 2013

Automatic Guided Vehicles (AGVs) are navigated in different ways, utilising multiple types of sen... more Automatic Guided Vehicles (AGVs) are navigated in different ways, utilising multiple types of sensors for detecting the environment. Different methods are then used to execute the navigation. In this research, such sensors are minimised by the use of an omnidirectional camera picture stream. The area of interest is extracted and by utilising image processing the vehicle is navigated on a set path. Utilising different coloured signs reconfigurability is added to the route layout resulting in the manipulation of a number of AGVs, each on its own designated coloured sign path by the operator with no programming alteration or intervention. A low-resolution camera and a MATLAB ® software development platform are utilised.

IEEE Power and Energy Society Conference and Exposition in Africa: Intelligent Grid Integration of Renewable Energy Resources (PowerAfrica), 2012

In many isolated and remotes rural areas not served by the grid, islanded hybrid renewable energy... more In many isolated and remotes rural areas not served by the grid, islanded hybrid renewable energy systems can be built as main source of electricity. The proper selection of the hybrid system with proper cost and sizing optimization of its components are important and diffi cUlt tasks, capital for the system viability. In this paper, the problem is expressed as an optimization problem which minimizes the size and initial cost of the system's components. This study proposes linear programming to optimize the above system's characteristics.

2013 IEEE International Conference on Industrial Technology (ICIT), 2013

Power and Energy Systems, 2012

Renewable energy advocates, the South African Government and investors are more and more becoming... more Renewable energy advocates, the South African Government and investors are more and more becoming aware of stream, river currents and their enormous associated energy potential. Since hydrokinetic power generation (HKP) relies basically on the extraction of energy from the natural velocity of free lowing water, this power system can be categorised as sources of flowing water with minimal civil infrastructure, environmental impacts and costs. This study investigates the possibility of using and developing hydrokinetic power to extend the reliable, affordable and sustainable electricity supplies for rural, remote and isolated loads in rural South Africa where reasonable water resource is available. Simulations are performed using the Hybrid Optimisation Model for Electric Renewable (HOMER) and the results are compared to those from other supply options such as standalone Photovoltaic system (PV), diesel generator (DG) and grid extension. Finally the paper points out some major challenges that are facing the development of this technology in South Africa.

Power and Energy Systems, 2012

A large amount of suitable sites to develop Micro/Pico hydro power in South Africa have not yet b... more A large amount of suitable sites to develop Micro/Pico hydro power in South Africa have not yet been developed, especially in areas not served by the grid. One valuable and cost effective way to optimize the deployment of Micro/Pico hydro power in those off-grid areas is by the utilization of simplistic and locally designed turbines coupled to squirrel-cage induction generators which have more advantages compared to conventional synchronous generators when used for rural applications. This paper presents a simple model of a standalone Micro hydropower composed of an induction generator directly coupled to a Kaplan water turbine. Mathematical and SIMULINK models are developed; simulations using MATLAB software are performed to highlight the characteristics of the output voltage when the mechanical input due to the water flow is varying. Experiments have been conducted on a prototype constructed in the lab to validate the results obtained from the theoretical developed model.

Energy Procedia, 2014

The aim of this paper is to investigate the potential use of Hydrokinetic-Diesel generator hybrid... more The aim of this paper is to investigate the potential use of Hydrokinetic-Diesel generator hybrid systems for sustainable and cost-effective electricity generation in rural South Africa. For this purpose different potential supply options are simulated using HOMER and the results are analyzed based on the Net Present Cost and the Cost of Energy produced. The simulation results show that Hydrokinetic-Diesel generator hybrid systems have lower net present costs as well as lower costs of energy compared to other supply options such as standalone Photovoltaic, Hydrokinetic or diesel generator.

Renewable and Sustainable Energy Reviews, 2014

Apparently, most hydrokinetic literatures mainly concentrate on large-scale technologies such as ... more Apparently, most hydrokinetic literatures mainly concentrate on large-scale technologies such as waves, tides and ocean current applications. This could be one of the reasons delaying the utilization of smallscale hydrokinetic river technology in rural areas. This paper therefore critically reviews the current status of micro-hydrokinetic river (MHR) technology for rural applications. Relevant research literatures based on developments, applications, design, operation as well as different MHR technologies involved in rural electrification projects have been reviewed. After conducting these reviews it has become clear that one of the key barriers hindering the employment of MHR technology in rural areas with access to flowing water is the lack of research demonstrating the technical, economic and environmental benefits of this technology compared to other rural electrification techniques. Studies that look towards the longterm perspective of techno-economic analysis inclusive of capital, maintenance and running costs computations need to be carried out promoting the interest in utilizing this technology. This paper will aid researchers to identify areas that need to improve as well as encourage public bodies to implement proper energy policies regarding the MHR technology usage in rural areas. It will also create awareness among site owners, investors, project developers and decision makers regarding the potential benefits of using this technology in rural areas especially in countries with little or no elevation.

Recently, a new type of Design-for-Delay-Testability (DfDT) structure and associated Built-In Sel... more Recently, a new type of Design-for-Delay-Testability (DfDT) structure and associated Built-In Self-Test architecture for detecting delay faults in digital highperformance circuits has been proposed. It circumvents the requirement of an expensive high-speed tester. In this paper, the ability of the proposed structure to function correctly in an environment with process- and application-induced variations has been investigated. Practical solutions to ensure proper operation of the DfDT structure will be proposed and verified by means of simulation. Due to the critical timing necessary when detecting small delay faults it is crucial to know what to expect from these variations and subsequently reduce their influence.

Recently, a new type of Design-for-Delay-Testability (DfDT) structure and associated Built-In Sel... more Recently, a new type of Design-for-Delay-Testability (DfDT) structure and associated Built-In Self-Test architecture for detecting delay faults in digital high-performance circuits has been proposed. It circumvents the requirement of an expensive high-speed tester. In this paper, the ability of the proposed structure to function correctly in an environment with process-and application-induced variations has been investigated. Practical solutions to ensure proper operation of the DfDT structure will be proposed and verified by means of simulation. Due to the critical timing necessary when detecting small delay faults it is crucial to know what to expect from these variations and subsequently reduce their influence.

Continual advances in the manufacturing processes of integrated circuits provide designers the ab... more Continual advances in the manufacturing processes of integrated circuits provide designers the ability to create more complex and denser architectures and increased functionality on a single chip. The increased usage of embedded cores necessitates a core-based test strategy in which cores are also tested separately. The IEEE P1500 proposed standard for Embedded Core Test (SECT) is a standard under development which aim is to improve the testing of core-based system chips. This paper deals with the enhancement of the Test Wrapper and Wrapper Cells to provide a structure to be able to test embedded cores for delay faults. This approach allows delay fault testing of cores by using the digital oscillation test method and the help of the enhanced elements while staying compliant to the P1500 standard.

This paper describes the possible implementation of an experimental three-dimensional photographi... more This paper describes the possible implementation of an experimental three-dimensional photographic system incorporating an unsophisticated laser scanning system and the results attained with such. Its use in determining the dimensional characteristics of components being transported on a conveyor system in an automated material-handling facility, as well as the transformation of its output into a file for rapid prototyping purposes is considered. A critical assessment of the operational characteristics of the system is presented.

Renewable Energy in the Service of Mankind Vol I, 2015

Standalone micro-hydrokinetic river (MHR) system is one of the promising technologies to be used ... more Standalone micro-hydrokinetic river (MHR) system is one of the promising technologies to be used for remote rural electrification. It simply requires the flow of water instead of elevation or head, leading to expensive civil works. This paper demonstrates an economic benefit offered by a standalone MHR system when compared to the commonly used standalone systems such as solar, wind and diesel generator (DG) at the selected study site in Kwazulu Natal. Wind speed and solar radiation data of the selected rural site have been taken from national aeronautics and space administration (NASA) surface meteorology database. The hybrid optimization model for electric renewable (HOMER) software was used to determine the most feasible solution when using MHR, solar, wind or DG system to supply 5 rural houses. MHR system proved to be the best cost-effective option to consider at the study site due to its low cost of energy (COE) and low net present cost (NPC).

One of the major challenges facing the growth of South Africa, the largest economy in Africa and ... more One of the major challenges facing the growth of South Africa, the largest economy in Africa and a member of the five major emerging national economies (BRICS) of the world, is unemployment. While there are other factors influencing unemployment, high dropout rates in universities are seen as a definite contributor to this challenge. Reflection and reflective practices have been extensively researched over the years by Richert, Moon and Green to name a few. The research question that arises that this paper attempts to address is what academics can do to reduce the high dropout rates of students in tertiary institution. The paper presents an effective teaching technique using the centric reflection model and the Greenaway’s model. The paper firstly looks at the actual causes behind the failures at first year level such as high student volume, language barrier and poor motivation. Secondly it details how a model was created using centric reflection model which addresses these causes a...

2010 IEEE International Symposium on Industrial Electronics, 2010

Automatic Guided Vehicles (AGV) are being used more frequently in a manufacturing environment. De... more Automatic Guided Vehicles (AGV) are being used more frequently in a manufacturing environment. Developing a platform that could be easily reconfigured is perhaps a more desirable option for a user with low capacity outputs. This research concentrates on an AGV and the development of the actuators and sensors, as well as the mounting of such for navigation and functionality, on such a vehicle.

Electric Power Systems Research, 2015

Micro-hydrokinetic river (MHR) system is one of the promising technologies to be used for remote ... more Micro-hydrokinetic river (MHR) system is one of the promising technologies to be used for remote rural electrification. In rural areas with access to both wind and flowing water resources, wind generation is selected as a first electrification priority. The potential benefit of generating electricity using flowing water resource is unnoticed. Hence, this paper presents the modelling and performance analysis of a MHR system as compared to wind generation system using MATLAB/Simulink software. These performances are compared to generate the same amount of electrical power. A permanent magnet synchronous generator (PMSG) has been chosen or used to investigate the behaviour of each system under variable speeds. The developed model includes horizontal turbine model, drive train model and PMSG model. The simulation results illustrate the ability of a hydrokinetic turbine driven PMSG to generate electricity markedly better and cheaper than a wind driven PMSG within South Africa. Hence, the MHR system presents a cheap electrification opportunity for poor rural households.

2013 6th Robotics and Mechatronics Conference (RobMech), 2013

Automatic Guided Vehicles (AGVs) are navigated in different ways, utilising multiple types of sen... more Automatic Guided Vehicles (AGVs) are navigated in different ways, utilising multiple types of sensors for detecting the environment. Different methods are then used to execute the navigation. In this research, such sensors are minimised by the use of an omnidirectional camera picture stream. The area of interest is extracted and by utilising image processing the vehicle is navigated on a set path. Utilising different coloured signs reconfigurability is added to the route layout resulting in the manipulation of a number of AGVs, each on its own designated coloured sign path by the operator with no programming alteration or intervention. A low-resolution camera and a MATLAB ® software development platform are utilised.

IEEE Power and Energy Society Conference and Exposition in Africa: Intelligent Grid Integration of Renewable Energy Resources (PowerAfrica), 2012

In many isolated and remotes rural areas not served by the grid, islanded hybrid renewable energy... more In many isolated and remotes rural areas not served by the grid, islanded hybrid renewable energy systems can be built as main source of electricity. The proper selection of the hybrid system with proper cost and sizing optimization of its components are important and diffi cUlt tasks, capital for the system viability. In this paper, the problem is expressed as an optimization problem which minimizes the size and initial cost of the system's components. This study proposes linear programming to optimize the above system's characteristics.

2013 IEEE International Conference on Industrial Technology (ICIT), 2013

Power and Energy Systems, 2012

Renewable energy advocates, the South African Government and investors are more and more becoming... more Renewable energy advocates, the South African Government and investors are more and more becoming aware of stream, river currents and their enormous associated energy potential. Since hydrokinetic power generation (HKP) relies basically on the extraction of energy from the natural velocity of free lowing water, this power system can be categorised as sources of flowing water with minimal civil infrastructure, environmental impacts and costs. This study investigates the possibility of using and developing hydrokinetic power to extend the reliable, affordable and sustainable electricity supplies for rural, remote and isolated loads in rural South Africa where reasonable water resource is available. Simulations are performed using the Hybrid Optimisation Model for Electric Renewable (HOMER) and the results are compared to those from other supply options such as standalone Photovoltaic system (PV), diesel generator (DG) and grid extension. Finally the paper points out some major challenges that are facing the development of this technology in South Africa.

Power and Energy Systems, 2012

A large amount of suitable sites to develop Micro/Pico hydro power in South Africa have not yet b... more A large amount of suitable sites to develop Micro/Pico hydro power in South Africa have not yet been developed, especially in areas not served by the grid. One valuable and cost effective way to optimize the deployment of Micro/Pico hydro power in those off-grid areas is by the utilization of simplistic and locally designed turbines coupled to squirrel-cage induction generators which have more advantages compared to conventional synchronous generators when used for rural applications. This paper presents a simple model of a standalone Micro hydropower composed of an induction generator directly coupled to a Kaplan water turbine. Mathematical and SIMULINK models are developed; simulations using MATLAB software are performed to highlight the characteristics of the output voltage when the mechanical input due to the water flow is varying. Experiments have been conducted on a prototype constructed in the lab to validate the results obtained from the theoretical developed model.

Energy Procedia, 2014

The aim of this paper is to investigate the potential use of Hydrokinetic-Diesel generator hybrid... more The aim of this paper is to investigate the potential use of Hydrokinetic-Diesel generator hybrid systems for sustainable and cost-effective electricity generation in rural South Africa. For this purpose different potential supply options are simulated using HOMER and the results are analyzed based on the Net Present Cost and the Cost of Energy produced. The simulation results show that Hydrokinetic-Diesel generator hybrid systems have lower net present costs as well as lower costs of energy compared to other supply options such as standalone Photovoltaic, Hydrokinetic or diesel generator.

Renewable and Sustainable Energy Reviews, 2014

Apparently, most hydrokinetic literatures mainly concentrate on large-scale technologies such as ... more Apparently, most hydrokinetic literatures mainly concentrate on large-scale technologies such as waves, tides and ocean current applications. This could be one of the reasons delaying the utilization of smallscale hydrokinetic river technology in rural areas. This paper therefore critically reviews the current status of micro-hydrokinetic river (MHR) technology for rural applications. Relevant research literatures based on developments, applications, design, operation as well as different MHR technologies involved in rural electrification projects have been reviewed. After conducting these reviews it has become clear that one of the key barriers hindering the employment of MHR technology in rural areas with access to flowing water is the lack of research demonstrating the technical, economic and environmental benefits of this technology compared to other rural electrification techniques. Studies that look towards the longterm perspective of techno-economic analysis inclusive of capital, maintenance and running costs computations need to be carried out promoting the interest in utilizing this technology. This paper will aid researchers to identify areas that need to improve as well as encourage public bodies to implement proper energy policies regarding the MHR technology usage in rural areas. It will also create awareness among site owners, investors, project developers and decision makers regarding the potential benefits of using this technology in rural areas especially in countries with little or no elevation.