title: Benchmarking attribute selection techniques for data mining

authors: Hall, Mark A.

subjects: computer science

abstract: Data engineering is generally considered to be a central issue in the development of data mining applications. The success of many learning schemes, in their attempts to construct models of data, hinges on the reliable identification of a small set of highly predictive attributes. The inclusion of irrelevant, redundant and noisy attributes in the model building process phase can result in poor predictive performance and increased computation. 
Attribute selection generally involves a combination of search and attribute utility estimation plus evaluation with respect to specific learning schemes. This leads to a large number of possible permutations and has led to a situation where very few benchmark studies have been conducted. 
This paper presents a benchmark comparison of several attribute selection methods. All the methods produce an attribute ranking, a useful devise of isolating the individual merit of an attribute. Attribute selection is achieved by cross-validating the rankings with respect to a learning scheme to find the best attributes. Results are reported for a selection of standard data sets and two learning schemes C4.5 and naive Bayes.

text: Benchmarking attribute selection techniques for data mining Data engineering is generally considered to be a central issue in the development of data mining applications. The success of many learning schemes, in their attempts to construct models of data, hinges on the reliable identification of a small set of highly predictive attributes. The inclusion of irrelevant, redundant and noisy attributes in the model building process phase can result in poor predictive performance and increased computation. 
Attribute selection generally involves a combination of search and attribute utility estimation plus evaluation with respect to specific learning schemes. This leads to a large number of possible permutations and has led to a situation where very few benchmark studies have been conducted. 
This paper presents a benchmark comparison of several attribute selection methods. All the methods produce an attribute ranking, a useful devise of isolating the individual merit of an attribute. Attribute selection is achieved by cross-validating the rankings with respect to a learning scheme to find the best attributes. Results are reported for a selection of standard data sets and two learning schemes C4.5 and naive Bayes.

year: 2000-07

title: Summer meltwater and spring sea ice primary production, light climate and nutrients in an Arctic estuary, Kangedussuaq, west Greenland

authors: Lund-Hansen, Lars Chresten

subjects: Science & Technology

abstract: The estuary is dominated by sea ice and snow cover from winter to spring, and a highly turbid meltwater plume during summer. The aims were to quantify the variability in optical conditions, inorganic nutrients, and primary production between these two extremes, and identify the drivers of variability. Data were obtained during a summer cruise along a transect in the estuary in August 2007, and a spring campaign on the ice in March 2011. The study comprises conductivity, temperature, and depth (CTD), K𝒹(PAR), K𝒹(λ), PAR transmittance, photic depth, chl-a, nutrients (NO₃, NO₂, NH₃, PO₄, and SiO₂), primary production, and sediment concentrations. PAR transmittance varied between 5% below snow and ice and 85% in clear water with 44% in turbid meltwater. Primary production rates were similar below the ice in March (76.8 mg C m⁻² d⁻¹) and in the highly turbid meltwater in August (94.8 mg C m⁻² d⁻¹), but higher (246.6 mg C m⁻² d⁻¹) at the mouth of the fjord. Meltwater inflow was the main driver of variability during summer and the snow and sea ice during spring. Under-ice primary production will increase three-fold with less snow on the sea ice, and the higher meltwater turbidity with increased melting of glacial ice and runoff will only reduce primary production slightly.

text: Summer meltwater and spring sea ice primary production, light climate and nutrients in an Arctic estuary, Kangedussuaq, west Greenland The estuary is dominated by sea ice and snow cover from winter to spring, and a highly turbid meltwater plume during summer. The aims were to quantify the variability in optical conditions, inorganic nutrients, and primary production between these two extremes, and identify the drivers of variability. Data were obtained during a summer cruise along a transect in the estuary in August 2007, and a spring campaign on the ice in March 2011. The study comprises conductivity, temperature, and depth (CTD), K𝒹(PAR), K𝒹(λ), PAR transmittance, photic depth, chl-a, nutrients (NO₃, NO₂, NH₃, PO₄, and SiO₂), primary production, and sediment concentrations. PAR transmittance varied between 5% below snow and ice and 85% in clear water with 44% in turbid meltwater. Primary production rates were similar below the ice in March (76.8 mg C m⁻² d⁻¹) and in the highly turbid meltwater in August (94.8 mg C m⁻² d⁻¹), but higher (246.6 mg C m⁻² d⁻¹) at the mouth of the fjord. Meltwater inflow was the main driver of variability during summer and the snow and sea ice during spring. Under-ice primary production will increase three-fold with less snow on the sea ice, and the higher meltwater turbidity with increased melting of glacial ice and runoff will only reduce primary production slightly.

year: 2018

title: The Mātauranga Māori in Mathematics Directive: Exploring the place of mātauranga Māori in Mathematics teaching and learning

authors: Williams, Jessica Elizabeth

subjects: mathematics education

abstract: This thesis explores issues concerning mātauranga Māori in mathematics teaching and learning here in Aotearoa. The Ministry of Education has directed that mana ōrite mō te mātauranga Māori be embedded in teaching, learning, and assessment. Thus, this research primarily aims to understand the development leading to the directive of including mātauranga Māori in education policies. For the English-medium secondary education settings, the second and third aims of this research are to explore what mātauranga Māori means to teachers of mathematics and to consider the connections between mātauranga Māori and mathematics teaching and learning. To investigate these aims, a semi-structured group discussion with four secondary mathematics teachers from an English-medium setting was conducted. The results of this thesis highlight the confusion and challenges secondary mathematics educators have toward defining, and subsequently, implementing mātauranga Māori in their classrooms. This thesis also found that there is enthusiasm and interest around learning how to ensure indigenous and marginalised learners reach their mathematics potential. Believing that indigenous worldviews have the potential to shift education outcomes for minority learners, this thesis adds to literature related to indigenous education, secondary mathematics education, and English-medium education of Māori learners.

text: The Mātauranga Māori in Mathematics Directive: Exploring the place of mātauranga Māori in Mathematics teaching and learning This thesis explores issues concerning mātauranga Māori in mathematics teaching and learning here in Aotearoa. The Ministry of Education has directed that mana ōrite mō te mātauranga Māori be embedded in teaching, learning, and assessment. Thus, this research primarily aims to understand the development leading to the directive of including mātauranga Māori in education policies. For the English-medium secondary education settings, the second and third aims of this research are to explore what mātauranga Māori means to teachers of mathematics and to consider the connections between mātauranga Māori and mathematics teaching and learning. To investigate these aims, a semi-structured group discussion with four secondary mathematics teachers from an English-medium setting was conducted. The results of this thesis highlight the confusion and challenges secondary mathematics educators have toward defining, and subsequently, implementing mātauranga Māori in their classrooms. This thesis also found that there is enthusiasm and interest around learning how to ensure indigenous and marginalised learners reach their mathematics potential. Believing that indigenous worldviews have the potential to shift education outcomes for minority learners, this thesis adds to literature related to indigenous education, secondary mathematics education, and English-medium education of Māori learners.

year: 2023