Browsing by Subject "ASM"

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    (En)Gendering the mineral supply chain: women's work and livelihoods in 3T extractivism in Africa's Great Lakes region
    (2026) Furniss, Allison; Ross, Fiona
    This dissertation examines the everyday working context of women along the 3T mineral supply chain in Africa's Great Lakes region. 3T's (tin, tungsten and tantalum) are collectively known as “digital minerals” and classified as critical minerals, central to the production of digital technologies. Using a broad definition of extractivism, this research focuses on women who work in artisanal and small-scale mines (ASM), as well as women in downstream production roles along the supply chain. This includes female mineral traders, transporters, mine owners and women working along the export route. As a multi-sited ethnography, this study uses participant observation, interview and focus group methodologies. The androcentrism of extractivism creates a working context with significant gendered divisions of labour, gendered vulnerabilities and barriers to work. Due to these factors, women experience various extractive violences in gendered ways. These include subtle violences that are material and embodied, premised on disposability. Nevertheless, within the overall working context for women, I argue that women's everyday actions, how they narrate their everyday working context and their “ways of operating” all show that women seek to reframe and insert themselves into dominant narratives, reject victimisation and reappropriate space and place in extractivism. These combined factors contribute to a slow acceptance of their participation. Lastly, I show that as one follows the chain of production, women's participation in extractivism decreases as economic opportunities increase, in an inverse relationship. By focusing on women who put the 3T mineral supply chain in motion and whose labour contributes to the manufacturing of digital technologies, this dissertation (en)genders a global supply chain. This research is based on 13 months of ethnographic fieldwork conducted in 2022-2023 in eastern Democratic Republic of the Congo, Rwanda and Tanzania.
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    Open Access
    A Heuristic Image Search Algorithm for Active Shape Model Segmentation of the Caudate Nucleus and Hippocampus in Brain MR Images of Children with FASD
    (South African Institute of Computer Scientists and Information Technologists, 2012) Eicher, A A; Marais, P; Warton, C; Jacobson, S W; Jacobson, J L; Molteno, C D; Meintjes, E M
    Magnetic Resonance Imaging provides a non-invasive means to study the neural correlates of Fetal Alcohol Spectrum Disorder (FASD) - the most common form of preventable mental retardation worldwide. One approach aims to detect brain abnormalities through an assessment of volume and shape of two sub-cortical structures, the caudate nucleus and hippocampus. We present a method for automatically segmenting these structures from high-resolution MR images captured as part of an ongoing study into the neural correlates of FASD. Our method incorporates an Active Shape Model, which is used to learn shape variation from manually segmented training data. A modified discrete Geometrically Deformable Model is used to generate point correspondence between training models. An ASM is then created from the landmark points. Experiments were conducted on the image search phase of ASM segmentation, in order to find the technique best suited to segmentation of the hippocampus and caudate nucleus. Various popular image search techniques were tested, including an edge detection method and a method based on grey profile Mahalanobis distance measurement. A novel heuristic image search method was also developed and tested. This heuristic method improves image segmentation by taking advantage of characteristics specific to the target data, such as a relatively homogeneous tissue colour in target structures. Results show that ASMs that use the heuristic image search technique produce the most accurate segmentations. An ASM constructed using this technique will enable researchers to quickly, reliably, and automatically segment test data for use in the FASD study.