title: Smoothing in Probability Estimation Trees

authors: Han, Zhimeng

subjects: Machine Learning

abstract: Classification learning is a type of supervised machine learning technique that uses a classification model (e.g. decision tree) to predict unknown class labels for previously unseen instances. In many applications it can be very useful to additionally obtain class probabilities for the different class labels. Decision trees that yield these probabilities are also called probability estimation trees (PETs). Smoothing is a technique used to improve the probability estimates. There are several existing smoothing methods, such as the Laplace correction, M-Estimate smoothing and M-Branch smoothing. Smoothing does not just apply to PETs. In the field of text compression, PPM in particular, smoothing methods play a important role. This thesis migrates smoothing methods from text compression to PETs. The newly migrated methods in PETs are compared with the best of the existing smoothing methods considered in this thesis under different experiment setups. Unpruned, pruned and bagged trees are considered in the experiments. The main finding is that the PPM-based methods yield the best probability estimate when used with bagged trees, but not when used with individual (pruned or unpruned) trees.

text: Smoothing in Probability Estimation Trees Classification learning is a type of supervised machine learning technique that uses a classification model (e.g. decision tree) to predict unknown class labels for previously unseen instances. In many applications it can be very useful to additionally obtain class probabilities for the different class labels. Decision trees that yield these probabilities are also called probability estimation trees (PETs). Smoothing is a technique used to improve the probability estimates. There are several existing smoothing methods, such as the Laplace correction, M-Estimate smoothing and M-Branch smoothing. Smoothing does not just apply to PETs. In the field of text compression, PPM in particular, smoothing methods play a important role. This thesis migrates smoothing methods from text compression to PETs. The newly migrated methods in PETs are compared with the best of the existing smoothing methods considered in this thesis under different experiment setups. Unpruned, pruned and bagged trees are considered in the experiments. The main finding is that the PPM-based methods yield the best probability estimate when used with bagged trees, but not when used with individual (pruned or unpruned) trees.

year: 2011

title: Prospectors and investors in the Te Aroha mining district during the 1930s

authors: Hart, Philip

abstract: This paper gives the ages, occupations, normal place of residence, mining experience, and other details that have been unearthed about all the men who acquired prospecting licenses and of five men who prospected for others during the Depression, with the exception of Malcolm Hardy and those associated with him, covered in another paper. Sometimes a mini-biography can be given, but usually the available information permits only a skeletal outline of their lives. Few had experience of mining, and in almost all cases their prospecting or investing reflected a desperate attempt to make some money at a time of considerable financial hardship. Their often-feeble attempts at prospecting or arranging for prospecting to be done produced no new discoveries and no ore of any value.
 Their lives and details of the extent of their involvement in mining are dealt with in alphabetical order.

text: Prospectors and investors in the Te Aroha mining district during the 1930s This paper gives the ages, occupations, normal place of residence, mining experience, and other details that have been unearthed about all the men who acquired prospecting licenses and of five men who prospected for others during the Depression, with the exception of Malcolm Hardy and those associated with him, covered in another paper. Sometimes a mini-biography can be given, but usually the available information permits only a skeletal outline of their lives. Few had experience of mining, and in almost all cases their prospecting or investing reflected a desperate attempt to make some money at a time of considerable financial hardship. Their often-feeble attempts at prospecting or arranging for prospecting to be done produced no new discoveries and no ore of any value.
 Their lives and details of the extent of their involvement in mining are dealt with in alphabetical order.

year: 2016

title: In what ways do the perceptions of connectedness of Māori students in Alternative Education secondary schools affect their self-efficacy within the learning environment?

authors: Lemon, Katrina Suezanne

subjects: Alternative Education

abstract: This study has sought to identify connectedness for Māori students within the alternative-education, learning environment and the effect this has had on their self-efficacy. Alternative education in New Zealand is described as a place where second chance learners have access to education (Alternative Education National Body New Zealand, 2016). Generally, students are referred to alternative education due to becoming habitual truants, while other students are deemed as behaviourally-challenging, and are consequently excluded from school (Education Review Office, 2010; Ministry of Education, 2016a). A Critical Theory approach was employed guided by Kaupapa Māori methodology. Data was collected using the qualitative methods of focus-group interviews and one-to-one semi-structured interviews. An open-coded approach was adopted to analyse the data from the interview transcripts where themes were selected, and a summary reflection was written. 

Three distant themes were identified during the data analysis phase: Tāhuhu Kōrero – Kura; Alternative Education – Kura; and Alternative Education Teaching and Learning Approaches.  Within these themes sub-themes were explored: perceptions and experiences of primary and secondary school; Māori in mainstream education; the referring schools involvement; misconceptions; connection to the alternative-education, learning environment; centre and teacher practices; connection with Māori; and pathways, mana, and self-efficacy. An important aspect of this study was to seek to understand these students’ prior educational experiences before gathering their narratives on the alternative-education, learning environment. This was a strength of the study as the student narratives on their entire educational journey provided a depth of understanding for the researcher, and went towards explaining their disconnection, how it happened, and gave context to their referral to alternative education. 

The student narratives expressed a strong sense of connection to their primary-school, learning environment, however, a complete disconnection to their secondary-school, learning environment. Students expressed feeling discriminated against for being Māori, that there was no empathy or understanding given to their lived realities despite wanting to succeed at school. They felt that their teachers did not make an effort to connect with them describing a power imbalance between the teachers and themselves. The students felt that expectations were low, and that teachers could not be bothered to help them with their work. The student participants attributed this disconnection to the reason for their truancy and behavioural issues. The student narratives on the alternative-education, learning environment described an environment that was: whānau; where teachers worked at a connection and understood their learners; challenging them academically; where the teachers were highly committed to their students; where trust and respect was built; and where one size did not fit all - flexibility was exercised. Students felt that the alternative-education, learning environment provided them with career ambition, and academic confidence resulting in self-efficacy. 

This study provides student voice from a group that was overlooked within the Te Kotahitanga research project (Bishop, Berryman, Tiakiwai, & Richardson, 2003). To hear the voice of alternative education students is important in seeking to improve educational success and enjoyment for Māori priority learners. If we get to know and understand what works for these priority learners, we can then work towards making a difference for them within mainstream education. This study aims to identify the importance of connectedness for Māori students and how connectedness will positively affect Māori learners and their self-efficacy. 


Kia mau ki tō Māoritanga.
Hold fast to your Māori culture.

text: In what ways do the perceptions of connectedness of Māori students in Alternative Education secondary schools affect their self-efficacy within the learning environment? This study has sought to identify connectedness for Māori students within the alternative-education, learning environment and the effect this has had on their self-efficacy. Alternative education in New Zealand is described as a place where second chance learners have access to education (Alternative Education National Body New Zealand, 2016). Generally, students are referred to alternative education due to becoming habitual truants, while other students are deemed as behaviourally-challenging, and are consequently excluded from school (Education Review Office, 2010; Ministry of Education, 2016a). A Critical Theory approach was employed guided by Kaupapa Māori methodology. Data was collected using the qualitative methods of focus-group interviews and one-to-one semi-structured interviews. An open-coded approach was adopted to analyse the data from the interview transcripts where themes were selected, and a summary reflection was written. 

Three distant themes were identified during the data analysis phase: Tāhuhu Kōrero – Kura; Alternative Education – Kura; and Alternative Education Teaching and Learning Approaches.  Within these themes sub-themes were explored: perceptions and experiences of primary and secondary school; Māori in mainstream education; the referring schools involvement; misconceptions; connection to the alternative-education, learning environment; centre and teacher practices; connection with Māori; and pathways, mana, and self-efficacy. An important aspect of this study was to seek to understand these students’ prior educational experiences before gathering their narratives on the alternative-education, learning environment. This was a strength of the study as the student narratives on their entire educational journey provided a depth of understanding for the researcher, and went towards explaining their disconnection, how it happened, and gave context to their referral to alternative education. 

The student narratives expressed a strong sense of connection to their primary-school, learning environment, however, a complete disconnection to their secondary-school, learning environment. Students expressed feeling discriminated against for being Māori, that there was no empathy or understanding given to their lived realities despite wanting to succeed at school. They felt that their teachers did not make an effort to connect with them describing a power imbalance between the teachers and themselves. The students felt that expectations were low, and that teachers could not be bothered to help them with their work. The student participants attributed this disconnection to the reason for their truancy and behavioural issues. The student narratives on the alternative-education, learning environment described an environment that was: whānau; where teachers worked at a connection and understood their learners; challenging them academically; where the teachers were highly committed to their students; where trust and respect was built; and where one size did not fit all - flexibility was exercised. Students felt that the alternative-education, learning environment provided them with career ambition, and academic confidence resulting in self-efficacy. 

This study provides student voice from a group that was overlooked within the Te Kotahitanga research project (Bishop, Berryman, Tiakiwai, & Richardson, 2003). To hear the voice of alternative education students is important in seeking to improve educational success and enjoyment for Māori priority learners. If we get to know and understand what works for these priority learners, we can then work towards making a difference for them within mainstream education. This study aims to identify the importance of connectedness for Māori students and how connectedness will positively affect Māori learners and their self-efficacy. 


Kia mau ki tō Māoritanga.
Hold fast to your Māori culture.

year: 2017