title: Improving ensembles and prediction intervals for machine learning on data streams

authors: Sun, Yibin

subjects: data streams

abstract: The rapid growth of streaming data presents significant challenges for traditional machine learning, including popular tasks like regression and classification. This thesis proposes adaptive and dynamic methods to address key issues, including concept drift, uncertainty quantification, and ensemble optimization, in evolving data streams.

The Self-Optimising K Nearest Leaves (SOKNL) regression algorithm integrates k-Nearest Neighbors (kNN) and Adaptive Random Forest Regression (ARF-Reg), dynamically optimizing neighbor selection to improve regression accuracy without relying on fixed window sizes. Extensive experimental results suggest that SOKNL outperforms the state-of-the-art streaming regression algorithms, including its origin, ARF-Reg.

For classification tasks, the Dynamic Ensemble Member Selection (DEMS) method dynamically adjusts ensemble size and selects members based on accuracy and diversity, improving predictive performance while handling concept drift. DEMS extends the idea of dynamic selection of ensemble members from SOKNL to classification tasks, with more flexible selection criteria.

The Adaptive Prediction Interval (AdaPI) framework provides robust uncertainty quantification by adaptively adjusting prediction intervals based on historical coverage, ensuring reliability in streaming regression. To evaluate prediction intervals holistically, the thesis introduces Coverage Interval Width in Non-dominated Groups (CING), a multi-objective evaluation method balancing interval width and coverage.

Aiming at analyzing the proposed methods for regression, this thesis also contributes the New Zealand Energy Pricing (NZEP) datasets, a comprehensive repository for real-time energy analytics. NZEP aims at providing a real, growing, customizable regression data source that can enrich the current regression benchmark data for stream learning, and potentially time-series.

By providing scalable, adaptive solutions for regression and classification, this research advances real-time decision-making in streaming data environments.

text: Improving ensembles and prediction intervals for machine learning on data streams The rapid growth of streaming data presents significant challenges for traditional machine learning, including popular tasks like regression and classification. This thesis proposes adaptive and dynamic methods to address key issues, including concept drift, uncertainty quantification, and ensemble optimization, in evolving data streams.

The Self-Optimising K Nearest Leaves (SOKNL) regression algorithm integrates k-Nearest Neighbors (kNN) and Adaptive Random Forest Regression (ARF-Reg), dynamically optimizing neighbor selection to improve regression accuracy without relying on fixed window sizes. Extensive experimental results suggest that SOKNL outperforms the state-of-the-art streaming regression algorithms, including its origin, ARF-Reg.

For classification tasks, the Dynamic Ensemble Member Selection (DEMS) method dynamically adjusts ensemble size and selects members based on accuracy and diversity, improving predictive performance while handling concept drift. DEMS extends the idea of dynamic selection of ensemble members from SOKNL to classification tasks, with more flexible selection criteria.

The Adaptive Prediction Interval (AdaPI) framework provides robust uncertainty quantification by adaptively adjusting prediction intervals based on historical coverage, ensuring reliability in streaming regression. To evaluate prediction intervals holistically, the thesis introduces Coverage Interval Width in Non-dominated Groups (CING), a multi-objective evaluation method balancing interval width and coverage.

Aiming at analyzing the proposed methods for regression, this thesis also contributes the New Zealand Energy Pricing (NZEP) datasets, a comprehensive repository for real-time energy analytics. NZEP aims at providing a real, growing, customizable regression data source that can enrich the current regression benchmark data for stream learning, and potentially time-series.

By providing scalable, adaptive solutions for regression and classification, this research advances real-time decision-making in streaming data environments.

year: 2025

title: Can biotic resistance be utilized to reduce establishment rates of non-indigenous species in constructed waters?

authors: Taylor, Claire Maree

subjects: exotic species

abstract: Understanding the mechanisms that facilitate establishment of non-indigenous species is imperative for devising techniques to reduce invasion rates. Passively dispersing non-indigenous organisms, including zooplankton, seemingly invade constructed waters (e.g., ornamental ponds, dams and reservoirs) at faster rates than natural lakes. A common attribute of these invaded water bodies is their relatively young age, leading to the assertion that low biotic resistance may lead to their higher vulnerability. Our aim was to determine if seeding of young water bodies with sediments containing diapausing stages of native zooplankton could accelerate community development, leading to greater biotic resistance to the establishment of new species. Twenty outdoor tanks were filled with water (1,400 L) and nutrients added to attain eutrophic conditions. Ten treatment tanks had sediments added, sourced from local water bodies. In the remaining ten, sediments were autoclaved, and received zooplankton via natural dispersal only. In an initial 12 month monitoring period, species richness increased at a greater rate in the treatment tanks (at 12 months average standing richness per tank = 3.8, accumulated richness = 8.2) than control tanks (2.6 and 5.0, P\0.05). Treatment tanks developed assemblages with greater proportions of species adapted to pelagic conditions, such as planktonic cladocerans and copepods, while control tanks generally comprised of smaller, littoral dwelling, rotifers. Analysis of similarities indicated community composition differed between the control and treatment groups at 12 months (P\0.01). Two copepod, four rotifer and one cladoceran species were intentionally added to tanks at 12 months. In the 3 month post-introduction period, five of these species established populations in the control tanks, while only two species established in the treatment tanks. The calanoid copepod Skistodiaptomus pallidus, for example, a non-indigenous species confined to constructed waters in New Zealand, established exclusively in tanks where native calanoid copepod species were absent (primarily control tanks). Our study suggests that biotic resistance could play an important role in reducing the establishment rate of non-indigenous zooplankton. It also provides evidence that seeding constructed water bodies with sediments containing diapausing eggs of native species may provide an effective management tool to reduce establishment rates of non-indigenous zooplankton.

text: Can biotic resistance be utilized to reduce establishment rates of non-indigenous species in constructed waters? Understanding the mechanisms that facilitate establishment of non-indigenous species is imperative for devising techniques to reduce invasion rates. Passively dispersing non-indigenous organisms, including zooplankton, seemingly invade constructed waters (e.g., ornamental ponds, dams and reservoirs) at faster rates than natural lakes. A common attribute of these invaded water bodies is their relatively young age, leading to the assertion that low biotic resistance may lead to their higher vulnerability. Our aim was to determine if seeding of young water bodies with sediments containing diapausing stages of native zooplankton could accelerate community development, leading to greater biotic resistance to the establishment of new species. Twenty outdoor tanks were filled with water (1,400 L) and nutrients added to attain eutrophic conditions. Ten treatment tanks had sediments added, sourced from local water bodies. In the remaining ten, sediments were autoclaved, and received zooplankton via natural dispersal only. In an initial 12 month monitoring period, species richness increased at a greater rate in the treatment tanks (at 12 months average standing richness per tank = 3.8, accumulated richness = 8.2) than control tanks (2.6 and 5.0, P\0.05). Treatment tanks developed assemblages with greater proportions of species adapted to pelagic conditions, such as planktonic cladocerans and copepods, while control tanks generally comprised of smaller, littoral dwelling, rotifers. Analysis of similarities indicated community composition differed between the control and treatment groups at 12 months (P\0.01). Two copepod, four rotifer and one cladoceran species were intentionally added to tanks at 12 months. In the 3 month post-introduction period, five of these species established populations in the control tanks, while only two species established in the treatment tanks. The calanoid copepod Skistodiaptomus pallidus, for example, a non-indigenous species confined to constructed waters in New Zealand, established exclusively in tanks where native calanoid copepod species were absent (primarily control tanks). Our study suggests that biotic resistance could play an important role in reducing the establishment rate of non-indigenous zooplankton. It also provides evidence that seeding constructed water bodies with sediments containing diapausing eggs of native species may provide an effective management tool to reduce establishment rates of non-indigenous zooplankton.

year: 2012

title: Māori cultural concepts and service provision for homeless Māori men

authors: Ellis, Kenneth Desmond

subjects: Maori cultural concepts

abstract: Homelessness is a pressing issue for indigenous minorities such as homeless Māori men. Their circumstances are more vulnerable in ways, than other homeless groups given that their lives are impacted upon by ongoing colonisation. Homeless Māori men, like other ‘indigenous homeless groups’, often find themselves homeless because of social/cultural dislocation where, they are disconnected from their culture and closest forms of support. This study set out to explore how homeless Māori men’s circumstances could be improved through administering interventions in the form of Māori cultural concepts like: manaakitanga, wairuatanga, whanaungatanga and whānau. The overall approach used to gather the research was based on hybridisation, where several different approaches were used simultaneously to generate research data. These were participant observation: a kaupapa Māori approach, semi structured interviewing, thematic analysis and the use of a socio-historical context to underpin the entire research process. Two groups of Māori participants were interviewed for this study, one group comprising staff members, and one made of homeless Māori men. Each group had a number of unique characteristics. For example, the entire staff group comprised skilled and qualified professionals, while the men’s group was made up of individuals with severely impoverished backgrounds. The study produced several conclusive findings to show how Māori cultural concepts were used successfully as forms of social interventions. Concepts like whanaungatanga, manaakitanga, wairuatanga and whānau, were shown to produce positive social outcomes for homeless Māori men. These outcomes helped the men to stabilise their lives, as they attempted reintegration.

text: Māori cultural concepts and service provision for homeless Māori men Homelessness is a pressing issue for indigenous minorities such as homeless Māori men. Their circumstances are more vulnerable in ways, than other homeless groups given that their lives are impacted upon by ongoing colonisation. Homeless Māori men, like other ‘indigenous homeless groups’, often find themselves homeless because of social/cultural dislocation where, they are disconnected from their culture and closest forms of support. This study set out to explore how homeless Māori men’s circumstances could be improved through administering interventions in the form of Māori cultural concepts like: manaakitanga, wairuatanga, whanaungatanga and whānau. The overall approach used to gather the research was based on hybridisation, where several different approaches were used simultaneously to generate research data. These were participant observation: a kaupapa Māori approach, semi structured interviewing, thematic analysis and the use of a socio-historical context to underpin the entire research process. Two groups of Māori participants were interviewed for this study, one group comprising staff members, and one made of homeless Māori men. Each group had a number of unique characteristics. For example, the entire staff group comprised skilled and qualified professionals, while the men’s group was made up of individuals with severely impoverished backgrounds. The study produced several conclusive findings to show how Māori cultural concepts were used successfully as forms of social interventions. Concepts like whanaungatanga, manaakitanga, wairuatanga and whānau, were shown to produce positive social outcomes for homeless Māori men. These outcomes helped the men to stabilise their lives, as they attempted reintegration.

year: 2010