title: How fractional are super-capacitors? Electrochemical Impedance Spectroscopy (EIS) measurements

authors: Wildschut, Gordan Leslie

abstract: Super-capacitors are seeing more frequent use in modern electronic designs. Measuring the impedance of such an energy storage device is a good way to characterise how it will behave in real world situations. Therefore this study aims to investigate the present methods of measuring impedance of super-capacitors, with a focus on characterising their properties.
There also seems to be an increasing need for better and more cost effective equipment to measure these devices. Many options exist, and some are well suited to the task however most instruments are either too complicated and difficult to use or too expensive (in the 10’s of thousands of dollars) or a combination of both.
This work presents a design for such an instrument which can perform these measurements at a fraction of the cost. The functionality and performance are described and compared to current commercial options. Super-capacitors of varying storage sizes and brands are measured and characterised, and discussed in comparison to batteries.

text: How fractional are super-capacitors? Electrochemical Impedance Spectroscopy (EIS) measurements Super-capacitors are seeing more frequent use in modern electronic designs. Measuring the impedance of such an energy storage device is a good way to characterise how it will behave in real world situations. Therefore this study aims to investigate the present methods of measuring impedance of super-capacitors, with a focus on characterising their properties.
There also seems to be an increasing need for better and more cost effective equipment to measure these devices. Many options exist, and some are well suited to the task however most instruments are either too complicated and difficult to use or too expensive (in the 10’s of thousands of dollars) or a combination of both.
This work presents a design for such an instrument which can perform these measurements at a fraction of the cost. The functionality and performance are described and compared to current commercial options. Super-capacitors of varying storage sizes and brands are measured and characterised, and discussed in comparison to batteries.

year: 2020

title: Simulation with real world network stacks

authors: Jansen, Sam

subjects: computer science

abstract: Network simulation is used widely in network research to test new protocols, modifications to existing protocols and new ideas. The tool used in many cases is ns-2. The nature of the ns-2 protocols means that they are often based on theoretical models that might not behave in the same way as real networks. This paper presents the Network Simulation Cradle which allows real world network stacks to be used in a wrapper that allows the stacks protocols to be used in the ns-2 network simulator. The network stacks from the open source operating systems Linux, FreeBSD and OpenBSD are included in the simulation cradle as well as a stack designed for embedded systems, lwIP. Our results show that ns-2's TCP implementations do not match observed behaviour from real machines in some respects and using the Network Simulation Cradle produces results closer to real world network stacks.

text: Simulation with real world network stacks Network simulation is used widely in network research to test new protocols, modifications to existing protocols and new ideas. The tool used in many cases is ns-2. The nature of the ns-2 protocols means that they are often based on theoretical models that might not behave in the same way as real networks. This paper presents the Network Simulation Cradle which allows real world network stacks to be used in a wrapper that allows the stacks protocols to be used in the ns-2 network simulator. The network stacks from the open source operating systems Linux, FreeBSD and OpenBSD are included in the simulation cradle as well as a stack designed for embedded systems, lwIP. Our results show that ns-2's TCP implementations do not match observed behaviour from real machines in some respects and using the Network Simulation Cradle produces results closer to real world network stacks.

year: 2005

title: Teachers' perceptions of the effectiveness of the Whānau Rūmaki teacher education programme, 1990-1992

authors: Kana, Fred

subjects: Maori Language

abstract: In 1990 the School of Education, the University of Waikato, initiated a special option within its regular pre-service teacher training programmes, an option designed to prepare teachers to deliver the New Zealand curriculum in bilingual and total immersion schools through the medium of te reo Māori. This alternative programmed, designated Whānau Rūmaki, was experimental and evolutionary. Inevitably particular elements of it had to be varied with each year's operation as its architects attempted 'to get the mix right'. It is difficult, however, when engaged in the day to day running of a programme, to stand back and review with any degree of objectivity its strengths and weaknesses. This study, therefore, in retrospect attempts to do three things: one, to follow the initial Whānau Rūmaki student cohort through its three or four year training cycle noting especially the difficulties confronting individual students some of whom dropped out of the programme; two, to gather information from as many as possible of the graduates who graduated about how well they felt they had been prepared for the rigours of classroom teaching; three, to be able, after analysing the data gathered, to recommend ways of improving the on-going Whānau Rūmaki programme.

text: Teachers' perceptions of the effectiveness of the Whānau Rūmaki teacher education programme, 1990-1992 In 1990 the School of Education, the University of Waikato, initiated a special option within its regular pre-service teacher training programmes, an option designed to prepare teachers to deliver the New Zealand curriculum in bilingual and total immersion schools through the medium of te reo Māori. This alternative programmed, designated Whānau Rūmaki, was experimental and evolutionary. Inevitably particular elements of it had to be varied with each year's operation as its architects attempted 'to get the mix right'. It is difficult, however, when engaged in the day to day running of a programme, to stand back and review with any degree of objectivity its strengths and weaknesses. This study, therefore, in retrospect attempts to do three things: one, to follow the initial Whānau Rūmaki student cohort through its three or four year training cycle noting especially the difficulties confronting individual students some of whom dropped out of the programme; two, to gather information from as many as possible of the graduates who graduated about how well they felt they had been prepared for the rigours of classroom teaching; three, to be able, after analysing the data gathered, to recommend ways of improving the on-going Whānau Rūmaki programme.

year: 1997