title: Evolving artificial datasets to improve interpretable classifiers

authors: Mayo, Michael

subjects: Machine learning

abstract: Differential Evolution can be used to construct effective and compact artificial training datasets for machine learning algorithms. In this paper, a series of comparative experiments are performed in which two simple interpretable supervised classifiers (specifically, Naive Bayes and linear Support Vector Machines) are trained (i) directly on “real” data, as would be the normal case, and (ii) indirectly, using special artificial datasets derived from real data via evolutionary optimization. The results across several challenging test problems show that supervised classifiers trained indirectly using our novel evolution-based approach produce models with superior predictive classification performance. Besides presenting the accuracy of the learned models, we also analyze the sensitivity of our artificial data optimization process to Differential Evolution's parameters, and then we examine the statistical characteristics of the artificial data that is evolved.

text: Evolving artificial datasets to improve interpretable classifiers Differential Evolution can be used to construct effective and compact artificial training datasets for machine learning algorithms. In this paper, a series of comparative experiments are performed in which two simple interpretable supervised classifiers (specifically, Naive Bayes and linear Support Vector Machines) are trained (i) directly on “real” data, as would be the normal case, and (ii) indirectly, using special artificial datasets derived from real data via evolutionary optimization. The results across several challenging test problems show that supervised classifiers trained indirectly using our novel evolution-based approach produce models with superior predictive classification performance. Besides presenting the accuracy of the learned models, we also analyze the sensitivity of our artificial data optimization process to Differential Evolution's parameters, and then we examine the statistical characteristics of the artificial data that is evolved.

year: 2014

title: George Devey: a Te Aroha carpenter and his family

authors: Hart, Philip

abstract: A cabinetmaker, George Devey brought his wife and young family to New Zealand in 1864, accompanied by his brother Jess, a blacksmith. After settling in Thames, from 1883 onwards they lived in Te Aroha, where George erected houses, built coaches, and was the local undertaker. He had the most minimal involvement in local mining possible: acquiring an interest in one claim. His unmarried brother was a blacksmith at Waiorongomai, but would die prematurely of cancer.
George was a leader of the Methodist community, in particular supervising the Sunday School at Waiorongomai for many years. He was involved in the wider community, and lived long enough to be regarded as one of the ‘old-timers’. Despite suffering from three accidents earlier in life, he would live until the age of 97.
His wife Ann first achieved prominence in 1877 for assaulting a teacher because one of her daughters had been chastised. In Te Aroha she worked as a nurse for many years, and was fondly remembered, although previously, when at Thames, her nursing was in part responsible for a maternal death. After she died, the community ensured that her memory was kept alive.
Outlines are given of the careers of their sons and daughters. One daughter, Caroline Ida, married a mostly successful businessman, but another, Laura, suffered from mental problems caused by ‘disappointment in love’. Although she found happiness with her second husband, a miner, her life was cut short in tragic fashion.

text: George Devey: a Te Aroha carpenter and his family A cabinetmaker, George Devey brought his wife and young family to New Zealand in 1864, accompanied by his brother Jess, a blacksmith. After settling in Thames, from 1883 onwards they lived in Te Aroha, where George erected houses, built coaches, and was the local undertaker. He had the most minimal involvement in local mining possible: acquiring an interest in one claim. His unmarried brother was a blacksmith at Waiorongomai, but would die prematurely of cancer.
George was a leader of the Methodist community, in particular supervising the Sunday School at Waiorongomai for many years. He was involved in the wider community, and lived long enough to be regarded as one of the ‘old-timers’. Despite suffering from three accidents earlier in life, he would live until the age of 97.
His wife Ann first achieved prominence in 1877 for assaulting a teacher because one of her daughters had been chastised. In Te Aroha she worked as a nurse for many years, and was fondly remembered, although previously, when at Thames, her nursing was in part responsible for a maternal death. After she died, the community ensured that her memory was kept alive.
Outlines are given of the careers of their sons and daughters. One daughter, Caroline Ida, married a mostly successful businessman, but another, Laura, suffered from mental problems caused by ‘disappointment in love’. Although she found happiness with her second husband, a miner, her life was cut short in tragic fashion.

year: 2016

title: The revitalisation roles of Māori-medium whānau

authors: Bryant, Braden

abstract: For over a century and a half, te reo Māori (the Māori language) has suffered from linguistic marginalisation, causing significant language shift to English, and, with it, generations of Māori who are unable to speak their indigenous language. While efforts since the 1970s to rebuild te reo Māori have primarily focused on educational initiatives such as kōhanga reo and kura kaupapa, there is now a move to shift the revitalisation strategy towards encouraging te reo Māori use in the home, and to rebuilding the language intergenerationally. Unfortunately, little is known about whānau perceptions regarding te reo Māori revitalisation, which is what this research investigates.

This research investigates five whānau who have committed their children to Māori-medium education. It aims to understand what influenced their decision-making around Māori-medium and what they see as the key benefits for their children. It also looks at what whānau consider to be obstacles regarding their use of te reo Māori, and at their commitment to Māori-medium education. Finally, this research aims to uncover how whānau perceive the wider revitalisation effort, and their roles in it.

The qualitative method of semi-structured interviews was used to conduct this research. The conversational nature of this method gives whānau the freedom to express their beliefs, while remaining on the main themes of this study. As the participants and themes of this research are Māori, the study used Kaupapa Māori theory and principles to guide it. This supported the overall aim of aligning with Māori aspirations, and safeguarding participants from exploitation.

This research found that perceptions of whānau often reflected the extent to which they had been affected by intergenerational language shift. Whānau still highly affected by language shift, and whose te reo Māori is less normalised in the home, prioritised te reo Māori learning at school as the key benefit of Māori-medium education. This group also faced more opposition to their Māori-medium choices from friends and whānau, and perceived their revitalisation roles to be more concerned with the immediate whānau. By contrast, the whānau who had managed to regenerate te reo Māori in their homes to a greater extent placed more emphasis on tikanga and values as benefits of Māori-medium education. They identified opposition from friends and whānau as a barrier to their promotion of te reo Māori, while also identifying their own subconscious lapses into English as a major barrier to maintaining normalised te reo Māori environments for their children. Finally, they perceived their revitalisation roles as revolving around normalising te reo Māori for their whānau and for their communities. They played important roles in establishing language domains for further use of what is their home language.

This small study shows the importance of understanding the perceptions of those who are central to the regeneration of te reo Māori because they are the key agents of successful change, and have the attitudes and skills to do so. A larger study would provide more data to support the formation of new language revitalisation strategies.

text: The revitalisation roles of Māori-medium whānau For over a century and a half, te reo Māori (the Māori language) has suffered from linguistic marginalisation, causing significant language shift to English, and, with it, generations of Māori who are unable to speak their indigenous language. While efforts since the 1970s to rebuild te reo Māori have primarily focused on educational initiatives such as kōhanga reo and kura kaupapa, there is now a move to shift the revitalisation strategy towards encouraging te reo Māori use in the home, and to rebuilding the language intergenerationally. Unfortunately, little is known about whānau perceptions regarding te reo Māori revitalisation, which is what this research investigates.

This research investigates five whānau who have committed their children to Māori-medium education. It aims to understand what influenced their decision-making around Māori-medium and what they see as the key benefits for their children. It also looks at what whānau consider to be obstacles regarding their use of te reo Māori, and at their commitment to Māori-medium education. Finally, this research aims to uncover how whānau perceive the wider revitalisation effort, and their roles in it.

The qualitative method of semi-structured interviews was used to conduct this research. The conversational nature of this method gives whānau the freedom to express their beliefs, while remaining on the main themes of this study. As the participants and themes of this research are Māori, the study used Kaupapa Māori theory and principles to guide it. This supported the overall aim of aligning with Māori aspirations, and safeguarding participants from exploitation.

This research found that perceptions of whānau often reflected the extent to which they had been affected by intergenerational language shift. Whānau still highly affected by language shift, and whose te reo Māori is less normalised in the home, prioritised te reo Māori learning at school as the key benefit of Māori-medium education. This group also faced more opposition to their Māori-medium choices from friends and whānau, and perceived their revitalisation roles to be more concerned with the immediate whānau. By contrast, the whānau who had managed to regenerate te reo Māori in their homes to a greater extent placed more emphasis on tikanga and values as benefits of Māori-medium education. They identified opposition from friends and whānau as a barrier to their promotion of te reo Māori, while also identifying their own subconscious lapses into English as a major barrier to maintaining normalised te reo Māori environments for their children. Finally, they perceived their revitalisation roles as revolving around normalising te reo Māori for their whānau and for their communities. They played important roles in establishing language domains for further use of what is their home language.

This small study shows the importance of understanding the perceptions of those who are central to the regeneration of te reo Māori because they are the key agents of successful change, and have the attitudes and skills to do so. A larger study would provide more data to support the formation of new language revitalisation strategies.

year: 2017