title: Feature extractor stacking for cross-domain few-shot learning

authors: Wang, Hongyu

subjects: cross-domain few-shot learning

abstract: Cross-domain few-shot learning (CDFSL) addresses learning problems where knowledge needs to be transferred from one or more source domains into an instance-scarce target domain with an explicitly different distribution. Recently published CDFSL methods generally construct a universal model that combines knowledge of multiple source domains into one feature extractor. This enables efficient inference but necessitates re-computation of the extractor whenever a new source domain is added. Some of these methods are also incompatible with heterogeneous source domain extractor architectures.

The first part of this thesis proposes feature extractor stacking (FES), a new CDFSL method for combining information from a collection of extractors, that can utilise heterogeneous pretrained extractors out of the box and does not maintain a universal model that needs to be re-computed when its extractor collection is updated. We present the basic FES algorithm, which is inspired by the classic stacked generalisation approach, and also introduce two variants: convolutional FES (ConFES) and regularised FES (ReFES). Given a target-domain task, these algorithms fine-tune each extractor independently, use cross-validation to extract training data for stacked generalisation from the support set, and learn a simple linear stacking classifier from this data. We evaluate our FES methods on the well-known Meta-Dataset benchmark, targeting image classification with convolutional neural networks, and show that they can achieve state-of-the-art performance.

The second part of this thesis proposes an efficient semi-supervised learning method that applies self-training to the classification head only and show that it can yield very consistent improvements in average performance in the Meta-Dataset benchmark for cross-domain few-shot learning when applied with FES and other contemporary methods utilising centroid-based classification.

The third part of this thesis proposes a bidirectional snapshot selection strategy for FES, leveraging its cross-validation process and the ordered nature of its snapshots, and demonstrates that a 95% snapshot reduction can be achieved while retaining the same level of accuracy.

text: Feature extractor stacking for cross-domain few-shot learning Cross-domain few-shot learning (CDFSL) addresses learning problems where knowledge needs to be transferred from one or more source domains into an instance-scarce target domain with an explicitly different distribution. Recently published CDFSL methods generally construct a universal model that combines knowledge of multiple source domains into one feature extractor. This enables efficient inference but necessitates re-computation of the extractor whenever a new source domain is added. Some of these methods are also incompatible with heterogeneous source domain extractor architectures.

The first part of this thesis proposes feature extractor stacking (FES), a new CDFSL method for combining information from a collection of extractors, that can utilise heterogeneous pretrained extractors out of the box and does not maintain a universal model that needs to be re-computed when its extractor collection is updated. We present the basic FES algorithm, which is inspired by the classic stacked generalisation approach, and also introduce two variants: convolutional FES (ConFES) and regularised FES (ReFES). Given a target-domain task, these algorithms fine-tune each extractor independently, use cross-validation to extract training data for stacked generalisation from the support set, and learn a simple linear stacking classifier from this data. We evaluate our FES methods on the well-known Meta-Dataset benchmark, targeting image classification with convolutional neural networks, and show that they can achieve state-of-the-art performance.

The second part of this thesis proposes an efficient semi-supervised learning method that applies self-training to the classification head only and show that it can yield very consistent improvements in average performance in the Meta-Dataset benchmark for cross-domain few-shot learning when applied with FES and other contemporary methods utilising centroid-based classification.

The third part of this thesis proposes a bidirectional snapshot selection strategy for FES, leveraging its cross-validation process and the ordered nature of its snapshots, and demonstrates that a 95% snapshot reduction can be achieved while retaining the same level of accuracy.

year: 2024

title: Plant availability of boron adsorbed or occulted on goethite to rape (Brassica napus L.) seedling

authors: Ren, Liying

subjects: boron-doped goethite

abstract: The purpose of the study was to determine plant availability of boron (B) and relaxation of soil acid to rape seedling exhibited by B-doped goethite in acidic soil. For this purpose, two kinds of B-doped goethite were synthesized: one was goethite with adsorbed B prepared by reacting goethite with borax solution, and the other was goethite with occluded B by synthesizing goethite in the presence of boric acid. The reaction process in soil-like natural minerals of the B-doped goethite was simulated in a rhizobox culture system. Results showed that the B-doped goethite can provide available B for rape growth. Its addition on acidic soil can alleviate soil acidification by increasing soil pH and decreasing soil exchangeable acid. The observation that nutrient uptake was improved supports the view that the B-doped goethite improved soil quality, as also proved by the increase of root morphology and dry weight.

text: Plant availability of boron adsorbed or occulted on goethite to rape (Brassica napus L.) seedling The purpose of the study was to determine plant availability of boron (B) and relaxation of soil acid to rape seedling exhibited by B-doped goethite in acidic soil. For this purpose, two kinds of B-doped goethite were synthesized: one was goethite with adsorbed B prepared by reacting goethite with borax solution, and the other was goethite with occluded B by synthesizing goethite in the presence of boric acid. The reaction process in soil-like natural minerals of the B-doped goethite was simulated in a rhizobox culture system. Results showed that the B-doped goethite can provide available B for rape growth. Its addition on acidic soil can alleviate soil acidification by increasing soil pH and decreasing soil exchangeable acid. The observation that nutrient uptake was improved supports the view that the B-doped goethite improved soil quality, as also proved by the increase of root morphology and dry weight.

year: 2010

title: Te karanga tūturu o maieke:  Ngāti Kuri women’s taiao geographies

authors: Ringham, Sandra Lee

subjects: Māori and Indigenous geographies

abstract: This research examines the relationships, identities and sense of belonging of Māori women of within the Ngāti Kuri iwi (tribe) and te taiao (the natural world, environment, nature, country) in Te Hiku o te Ika, Far North, Aotearoa New Zealand. It shows how Ngāti Kuri women and te taiao are embedded in - yet also resist - colonial and patriarchal discourses. 
The Kaupapa Māori and Mana Wahine theoretical framework decolonises and transforms the ways in which Māori women have been represented and marginalised. Pūrākau (storywork) as a theory and methodology ensures Ngāti Kuri women’s stories are told by them and for them. Indigenous relational geography is woven into the theoretical framework to further understand Indigenous relationships to place and diverse feelings of belonging and responsibility.
Whakawhiti kōrero (research conversations), wānanga (workshops) and tipi haere (mobile wānanga) were carried out with 19 Ngāti Kuri women. Approximately 40 people from the iwi and / or scientific communities contribute to the thesis through the initiatives of the Ngāti Kuri Relationship Working Group (NKRWG), the Auckland War Memorial Museum and other research partners and as conservationists. 
Findings are organised around three themes: identities; relationships; and a sense of belonging. The first theme introduces Ngāti Kuri women’s identities as leaders and drivers of change, disrupting and dismantling the intersection of patriarchal and colonial discourse. The pūrākau of Maieke, a founding ancestress of Ngāti Kuri, brings to light the reclamation and transformation of Māori women’s identities and geographies, as defined by participants. Pre-colonisation Ngāti Kuri women had the capacity and authority to become a governing force in the daily lives of the iwi. The second theme highlights colonial and patriarchal naming of our world. Ngāti Kuri women are reconfiguring relationships and representation through the scientific naming of taonga (culturally valuable objects and species). Values and principles of kaitiakitanga (inherited guardianship) and whakawhanaugatanga (relating well to others) guide the naming process. The third theme focuses on participants’ reflections and understandings of the ways in which they sense place and feelings of belonging. Participants’ engagement with te taiao - through singing, storying and sensing place – highlights the way te taiao re-centres and transforms Ngāti Kuri women’s relationships and experiences of belonging to iwi homelands.
Importantly, the thesis concludes with a discussion of the challenges, successes and actions of Ngāti Kuri women as they continue to strive for tino rangatiratanga (self-determination), social and environmental well-being. I conceptualise new geographies that account for, and celebrate, uniquely Ngāti Kuri understandings of identities, relationships and feelings of belonging. Finally, a short creative story ends the thesis in order to show the transformative power of Ngāti Kuri women’s te taiao experiences.

text: Te karanga tūturu o maieke:  Ngāti Kuri women’s taiao geographies This research examines the relationships, identities and sense of belonging of Māori women of within the Ngāti Kuri iwi (tribe) and te taiao (the natural world, environment, nature, country) in Te Hiku o te Ika, Far North, Aotearoa New Zealand. It shows how Ngāti Kuri women and te taiao are embedded in - yet also resist - colonial and patriarchal discourses. 
The Kaupapa Māori and Mana Wahine theoretical framework decolonises and transforms the ways in which Māori women have been represented and marginalised. Pūrākau (storywork) as a theory and methodology ensures Ngāti Kuri women’s stories are told by them and for them. Indigenous relational geography is woven into the theoretical framework to further understand Indigenous relationships to place and diverse feelings of belonging and responsibility.
Whakawhiti kōrero (research conversations), wānanga (workshops) and tipi haere (mobile wānanga) were carried out with 19 Ngāti Kuri women. Approximately 40 people from the iwi and / or scientific communities contribute to the thesis through the initiatives of the Ngāti Kuri Relationship Working Group (NKRWG), the Auckland War Memorial Museum and other research partners and as conservationists. 
Findings are organised around three themes: identities; relationships; and a sense of belonging. The first theme introduces Ngāti Kuri women’s identities as leaders and drivers of change, disrupting and dismantling the intersection of patriarchal and colonial discourse. The pūrākau of Maieke, a founding ancestress of Ngāti Kuri, brings to light the reclamation and transformation of Māori women’s identities and geographies, as defined by participants. Pre-colonisation Ngāti Kuri women had the capacity and authority to become a governing force in the daily lives of the iwi. The second theme highlights colonial and patriarchal naming of our world. Ngāti Kuri women are reconfiguring relationships and representation through the scientific naming of taonga (culturally valuable objects and species). Values and principles of kaitiakitanga (inherited guardianship) and whakawhanaugatanga (relating well to others) guide the naming process. The third theme focuses on participants’ reflections and understandings of the ways in which they sense place and feelings of belonging. Participants’ engagement with te taiao - through singing, storying and sensing place – highlights the way te taiao re-centres and transforms Ngāti Kuri women’s relationships and experiences of belonging to iwi homelands.
Importantly, the thesis concludes with a discussion of the challenges, successes and actions of Ngāti Kuri women as they continue to strive for tino rangatiratanga (self-determination), social and environmental well-being. I conceptualise new geographies that account for, and celebrate, uniquely Ngāti Kuri understandings of identities, relationships and feelings of belonging. Finally, a short creative story ends the thesis in order to show the transformative power of Ngāti Kuri women’s te taiao experiences.

year: 2022