title: Mining data streams using option trees (revised edition, 2004)

authors: Holmes, Geoffrey

subjects: Machine learning

abstract: The data stream model for data mining places harsh restrictions on a learning algorithm. A model must be induced following the briefest interrogation of the data, must use only available memory and must update itself over time within these constraints. Additionally, the model must be able to be used for data mining at any point in time.
This paper describes a data stream classi_cation algorithm using an ensemble of option trees. The ensemble of trees is induced by boosting and iteratively combined into a single interpretable model. The algorithm is evaluated using benchmark datasets for accuracy against state-of-the-art algorithms that make use of the entire dataset.

text: Mining data streams using option trees (revised edition, 2004) The data stream model for data mining places harsh restrictions on a learning algorithm. A model must be induced following the briefest interrogation of the data, must use only available memory and must update itself over time within these constraints. Additionally, the model must be able to be used for data mining at any point in time.
This paper describes a data stream classi_cation algorithm using an ensemble of option trees. The ensemble of trees is induced by boosting and iteratively combined into a single interpretable model. The algorithm is evaluated using benchmark datasets for accuracy against state-of-the-art algorithms that make use of the entire dataset.

year: 2004-01-01

title: Characteristics of sub-surface sediments in southern Stella Passage, Tauranga Harbour

authors: Moon, Vicki G.

abstract: The Port of Tauranga is considering port developments that would require capital dredging of a section of the southern Stella Passage to achieve depths comparable to the northern Stella Passage. Seismic profiles, core samples, and	CPT data were	collected by the University of Waikato and OPUS for the area impacted by proposed development.

The core samples were analysed for sediment texture, including assessment	of the fines (silt + clay) content. Four main stratigraphic	units were identified from the available data. These were, in order of increasing stratigraphic depth and age: Holocene sand; Pleistocene alluvial fan; Pleistocene organic silt; and Pleistocene terrestrial and shallow marine sand. In general, the fines content increased with depth and age. Younger units thin southwards along Stella Passage, resulting in increasing fines content southwards along the channel.

text: Characteristics of sub-surface sediments in southern Stella Passage, Tauranga Harbour The Port of Tauranga is considering port developments that would require capital dredging of a section of the southern Stella Passage to achieve depths comparable to the northern Stella Passage. Seismic profiles, core samples, and	CPT data were	collected by the University of Waikato and OPUS for the area impacted by proposed development.

The core samples were analysed for sediment texture, including assessment	of the fines (silt + clay) content. Four main stratigraphic	units were identified from the available data. These were, in order of increasing stratigraphic depth and age: Holocene sand; Pleistocene alluvial fan; Pleistocene organic silt; and Pleistocene terrestrial and shallow marine sand. In general, the fines content increased with depth and age. Younger units thin southwards along Stella Passage, resulting in increasing fines content southwards along the channel.

year: 2019

title: Inequities in Covid-19 Omicron infections and hospitalisations for Māori and Pacific people in Te Manawa Taki Midland region, New Zealand

authors: Whitehead, Jesse

abstract: Covid-19 impacts population health equity. While mRNA vaccines protect against serious illness and death, little New Zealand (NZ) data exists about the impact of Omicron - and effectiveness of vaccination - on different population groups. We aim to examine the impact of  Omicron  on Māori, Pacific and Other ethnicities and how this interacts with age and vaccination status in the Te Manawa Taki Midland region of NZ. Daily Covid-19 infection and hospitalisation rates (01/02/2022 - 29/06/2022) were calculated for Māori, Pacific and Other ethnicities for six age bands. A multivariate logistic regression model quantified the effects of ethnicity, age, and vaccination on hospitalisation rates. Per-capita Omicron cases were highest and occurred earliest among Pacific (9 per 1,000) and Māori (5 per 1,000) people and were highest among 12-24 year-olds (7 per 1,000). Hospitalisation was significantly more likely for Māori (OR=2.03), Pacific people (OR=1.75), over 75-year olds (OR=39.22), and unvaccinated people (OR=4.64). Length of hospitalisation is strongly related to age. Covid-19 vaccination reduces hospitalisations for older individuals and Māori and Pacific populations. Omicron inequitably impacted Māori and Pacific people through higher per-capita infection and hospitalisation rates. Older people are more likely to be hospitalised and for longer.

text: Inequities in Covid-19 Omicron infections and hospitalisations for Māori and Pacific people in Te Manawa Taki Midland region, New Zealand Covid-19 impacts population health equity. While mRNA vaccines protect against serious illness and death, little New Zealand (NZ) data exists about the impact of Omicron - and effectiveness of vaccination - on different population groups. We aim to examine the impact of  Omicron  on Māori, Pacific and Other ethnicities and how this interacts with age and vaccination status in the Te Manawa Taki Midland region of NZ. Daily Covid-19 infection and hospitalisation rates (01/02/2022 - 29/06/2022) were calculated for Māori, Pacific and Other ethnicities for six age bands. A multivariate logistic regression model quantified the effects of ethnicity, age, and vaccination on hospitalisation rates. Per-capita Omicron cases were highest and occurred earliest among Pacific (9 per 1,000) and Māori (5 per 1,000) people and were highest among 12-24 year-olds (7 per 1,000). Hospitalisation was significantly more likely for Māori (OR=2.03), Pacific people (OR=1.75), over 75-year olds (OR=39.22), and unvaccinated people (OR=4.64). Length of hospitalisation is strongly related to age. Covid-19 vaccination reduces hospitalisations for older individuals and Māori and Pacific populations. Omicron inequitably impacted Māori and Pacific people through higher per-capita infection and hospitalisation rates. Older people are more likely to be hospitalised and for longer.

year: 2023-04-24