title: Text categorization using compression models

authors: Frank, Eibe

subjects: computer science

abstract: Text categorization, or the assignment of natural language texts to predefined categories based on their content, is of growing importance as the volume of information available on the internet continues to overwhelm us. The use of predefined categories implies a “supervised learning” approach to categorization, where already-classified articles which effectively define the categories are used as “training data” to build a model that can be used for classifying new articles that comprise the “test data”. This contrasts with “unsupervised” learning, where there is no training data and clusters of like documents are sought amongst the test articles. With supervised learning, meaningful labels (such as keyphrases) are attached to the training documents, and appropriate labels can be assigned automatically to test documents depending on which category they fall into.

text: Text categorization using compression models Text categorization, or the assignment of natural language texts to predefined categories based on their content, is of growing importance as the volume of information available on the internet continues to overwhelm us. The use of predefined categories implies a “supervised learning” approach to categorization, where already-classified articles which effectively define the categories are used as “training data” to build a model that can be used for classifying new articles that comprise the “test data”. This contrasts with “unsupervised” learning, where there is no training data and clusters of like documents are sought amongst the test articles. With supervised learning, meaningful labels (such as keyphrases) are attached to the training documents, and appropriate labels can be assigned automatically to test documents depending on which category they fall into.

year: 2000-01

title: The integration of heat pumps with biomass boiler flue gas for generating hot water

authors: Muldoon, Catherine

subjects: Biomass boiler

abstract: Achieving the goal of net zero greenhouse gases by 2050 requires reducing demand and switching from fossil fuels to renewables. Process heat in New Zealand is a significant source of greenhouse gas emissions. Transitioning to biomass boilers could lower emissions and offer opportunities for waste heat recovery by integrating heat pumps with the flue gas.
This thesis evaluates heat pump integration for hot water production, supplying low temperature process heat. Using an industrial case study, a boiler model is developed and confirmed against industrial measurements. Flue gas composition is modelled to determine temperature-enthalpy profiles, and therefore the heat available for recovery and upgrade. Combustion is modelled for different biomass fuels and varying flue gas oxygen levels. The higher moisture fuels showed increased availability of heat for utilisation, which decreased as flue gas oxygen levels increased.
Three heat pump cycles are explored to maximise efficiency. Refrigerant selection is considered with respect to environmental factors and thermodynamic suitability. Using a basic cycle heat pump the three most promising refrigerants, ammonia, propane and cyclopropane, were identified and considered in more detail for the industrial case. Subcooling improved efficiency and should be maximised. An internal heat exchanger also improves efficiency and reliability and should be considered. Two zeotropic mixtures were investigated to take advantage of the temperature glide. The propane-pentane (50wt%-50wt%) blend matched the temperature profile more closely and provided increases in COP.
To make the most of the latent heat in the flue gas, the evaporator temperature must be much lower than the dew point. However, absorbing heat from low source temperatures results in lower COPs, but higher volumes of hot water generated.

text: The integration of heat pumps with biomass boiler flue gas for generating hot water Achieving the goal of net zero greenhouse gases by 2050 requires reducing demand and switching from fossil fuels to renewables. Process heat in New Zealand is a significant source of greenhouse gas emissions. Transitioning to biomass boilers could lower emissions and offer opportunities for waste heat recovery by integrating heat pumps with the flue gas.
This thesis evaluates heat pump integration for hot water production, supplying low temperature process heat. Using an industrial case study, a boiler model is developed and confirmed against industrial measurements. Flue gas composition is modelled to determine temperature-enthalpy profiles, and therefore the heat available for recovery and upgrade. Combustion is modelled for different biomass fuels and varying flue gas oxygen levels. The higher moisture fuels showed increased availability of heat for utilisation, which decreased as flue gas oxygen levels increased.
Three heat pump cycles are explored to maximise efficiency. Refrigerant selection is considered with respect to environmental factors and thermodynamic suitability. Using a basic cycle heat pump the three most promising refrigerants, ammonia, propane and cyclopropane, were identified and considered in more detail for the industrial case. Subcooling improved efficiency and should be maximised. An internal heat exchanger also improves efficiency and reliability and should be considered. Two zeotropic mixtures were investigated to take advantage of the temperature glide. The propane-pentane (50wt%-50wt%) blend matched the temperature profile more closely and provided increases in COP.
To make the most of the latent heat in the flue gas, the evaporator temperature must be much lower than the dew point. However, absorbing heat from low source temperatures results in lower COPs, but higher volumes of hot water generated.

year: 2024

title: Words on Walls: Te reo Māori (loan)words in Aotearoa New Zealand primary school classrooms

authors: Burnette, Jessie

abstract: The unique language contact situation within Aotearoa New Zealand has informed a range of studies of the defining and increasingly salient feature of New Zealand English (NZE): the integration of loanwords from the indigenous, donor language, te reo Māori, into the dominant recipient language, English (Hay et al. 2008). As NZE is experiencing a state of great lexical flux, it is important to establish which (loan)words children are regularly exposed to and what social meanings they may be acquiring in relation to these. One relevant domain that can be examined for this purpose is that of the classroom. The classroom is educational in the traditional sense, but also in the developmental sense, in the acquisition of broader social meaning. Previous schoolscape research has highlighted not only the pedagogical importance of these spaces, but their influence in the construction and transmission of language ideologies (Pzymus and Huddleston 2021; Brown 2012). The present study aims to answer two questions: RQ1) Which (loan)words are children regularly exposed to through schoolscapes in Aotearoa (and do these words align with the loanwords identified as frequently appearing in previously collected corpora)? RQ2) What implicit language ideologies does the presentation of loanwords display (e.g. are loanwords presented as ‘flagged’/foreign (Levendis and Calude 2019))? This study brings together quantitative and qualitative analysis methods in an in-depth investigation of nine classrooms within three separate primary schools, and aims to provide a broad and perationalizable framework for conducting LL.

text: Words on Walls: Te reo Māori (loan)words in Aotearoa New Zealand primary school classrooms The unique language contact situation within Aotearoa New Zealand has informed a range of studies of the defining and increasingly salient feature of New Zealand English (NZE): the integration of loanwords from the indigenous, donor language, te reo Māori, into the dominant recipient language, English (Hay et al. 2008). As NZE is experiencing a state of great lexical flux, it is important to establish which (loan)words children are regularly exposed to and what social meanings they may be acquiring in relation to these. One relevant domain that can be examined for this purpose is that of the classroom. The classroom is educational in the traditional sense, but also in the developmental sense, in the acquisition of broader social meaning. Previous schoolscape research has highlighted not only the pedagogical importance of these spaces, but their influence in the construction and transmission of language ideologies (Pzymus and Huddleston 2021; Brown 2012). The present study aims to answer two questions: RQ1) Which (loan)words are children regularly exposed to through schoolscapes in Aotearoa (and do these words align with the loanwords identified as frequently appearing in previously collected corpora)? RQ2) What implicit language ideologies does the presentation of loanwords display (e.g. are loanwords presented as ‘flagged’/foreign (Levendis and Calude 2019))? This study brings together quantitative and qualitative analysis methods in an in-depth investigation of nine classrooms within three separate primary schools, and aims to provide a broad and perationalizable framework for conducting LL.

year: 2024