6,406 research outputs found

    Meso-scale FDM material layout design strategies under manufacturability constraints and fracture conditions

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    In the manufacturability-driven design (MDD) perspective, manufacturability of the product or system is the most important of the design requirements. In addition to being able to ensure that complex designs (e.g., topology optimization) are manufacturable with a given process or process family, MDD also helps mechanical designers to take advantage of unique process-material effects generated during manufacturing. One of the most recognizable examples of this comes from the scanning-type family of additive manufacturing (AM) processes; the most notable and familiar member of this family is the fused deposition modeling (FDM) or fused filament fabrication (FFF) process. This process works by selectively depositing uniform, approximately isotropic beads or elements of molten thermoplastic material (typically structural engineering plastics) in a series of pre-specified traces to build each layer of the part. There are many interesting 2-D and 3-D mechanical design problems that can be explored by designing the layout of these elements. The resulting structured, hierarchical material (which is both manufacturable and customized layer-by-layer within the limits of the process and material) can be defined as a manufacturing process-driven structured material (MPDSM). This dissertation explores several practical methods for designing these element layouts for 2-D and 3-D meso-scale mechanical problems, focusing ultimately on design-for-fracture. Three different fracture conditions are explored: (1) cases where a crack must be prevented or stopped, (2) cases where the crack must be encouraged or accelerated, and (3) cases where cracks must grow in a simple pre-determined pattern. Several new design tools, including a mapping method for the FDM manufacturability constraints, three major literature reviews, the collection, organization, and analysis of several large (qualitative and quantitative) multi-scale datasets on the fracture behavior of FDM-processed materials, some new experimental equipment, and the refinement of a fast and simple g-code generator based on commercially-available software, were developed and refined to support the design of MPDSMs under fracture conditions. The refined design method and rules were experimentally validated using a series of case studies (involving both design and physical testing of the designs) at the end of the dissertation. Finally, a simple design guide for practicing engineers who are not experts in advanced solid mechanics nor process-tailored materials was developed from the results of this project.U of I OnlyAuthor's request

    An exploration of the language within Ofsted reports and their influence on primary school performance in mathematics: a mixed methods critical discourse analysis

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    This thesis contributes to the understanding of the language of Ofsted reports, their similarity to one another and associations between different terms used within ‘areas for improvement’ sections and subsequent outcomes for pupils. The research responds to concerns from serving headteachers that Ofsted reports are overly similar, do not capture the unique story of their school, and are unhelpful for improvement. In seeking to answer ‘how similar are Ofsted reports’ the study uses two tools, a plagiarism detection software (Turnitin) and a discourse analysis tool (NVivo) to identify trends within and across a large corpus of reports. The approach is based on critical discourse analysis (Van Dijk, 2009; Fairclough, 1989) but shaped in the form of practitioner enquiry seeking power in the form of impact on pupils and practitioners, rather than a more traditional, sociological application of the method. The research found that in 2017, primary school section 5 Ofsted reports had more than half of their content exactly duplicated within other primary school inspection reports published that same year. Discourse analysis showed the quality assurance process overrode variables such as inspector designation, gender, or team size, leading to three distinct patterns of duplication: block duplication, self-referencing, and template writing. The most unique part of a report was found to be the ‘area for improvement’ section, which was tracked to externally verified outcomes for pupils using terms linked to ‘mathematics’. Those required to improve mathematics in their areas for improvement improved progress and attainment in mathematics significantly more than national rates. These findings indicate that there was a positive correlation between the inspection reporting process and a beneficial impact on pupil outcomes in mathematics, and that the significant similarity of one report to another had no bearing on the usefulness of the report for school improvement purposes within this corpus

    CFLIT: Coexisting Federated Learning and Information Transfer

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    Future wireless networks are expected to support diverse mobile services, including artificial intelligence (AI) services and ubiquitous data transmissions. Federated learning (FL), as a revolutionary learning approach, enables collaborative AI model training across distributed mobile edge devices. By exploiting the superposition property of multiple-access channels, over-the-air computation allows concurrent model uploading from massive devices over the same radio resources, and thus significantly reduces the communication cost of FL. In this paper, we study the coexistence of over-the-air FL and traditional information transfer (IT) in a mobile edge network. We propose a coexisting federated learning and information transfer (CFLIT) communication framework, where the FL and IT devices share the wireless spectrum in an OFDM system. Under this framework, we aim to maximize the IT data rate and guarantee a given FL convergence performance by optimizing the long-term radio resource allocation. A key challenge that limits the spectrum efficiency of the coexisting system lies in the large overhead incurred by frequent communication between the server and edge devices for FL model aggregation. To address the challenge, we rigorously analyze the impact of the computation-to-communication ratio on the convergence of over-the-air FL in wireless fading channels. The analysis reveals the existence of an optimal computation-to-communication ratio that minimizes the amount of radio resources needed for over-the-air FL to converge to a given error tolerance. Based on the analysis, we propose a low-complexity online algorithm to jointly optimize the radio resource allocation for both the FL devices and IT devices. Extensive numerical simulations verify the superior performance of the proposed design for the coexistence of FL and IT devices in wireless cellular systems.Comment: The paper has been accepted for publication by IEEE Transactions on Wireless Communications (March 2023

    Consent and the Construction of the Volunteer: Institutional Settings of Experimental Research on Human Beings in Britain during the Cold War

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    This study challenges the primacy of consent in the history of human experimentation and argues that privileging the cultural frameworks adds nuance to our understanding of the construction of the volunteer in the period 1945 to 1970. Historians and bio-ethicists have argued that medical ethics codes have marked out the parameters of using people as subjects in medical scientific research and that the consent of the subjects was fundamental to their status as volunteers. However, the temporality of the creation of medical ethics codes means that they need to be understood within their historical context. That medical ethics codes arose from a specific historical context rather than a concerted and conscious determination to safeguard the well-being of subjects needs to be acknowledged. The British context of human experimentation is under-researched and there has been even less focus on the cultural frameworks within which experiments took place. This study demonstrates, through a close analysis of the Medical Research Council's Common Cold Research Unit (CCRU) and the government's military research facility, the Chemical Defence Experimental Establishment, Porton Down (Porton), that the `volunteer' in human experiments was a subjective entity whose identity was specific to the institution which recruited and made use of the subject. By examining representations of volunteers in the British press, the rhetoric of the government's collectivist agenda becomes evident and this fed into the institutional construction of the volunteer at the CCRU. In contrast, discussions between Porton scientists, staff members, and government officials demonstrate that the use of military personnel in secret chemical warfare experiments was far more complex. Conflicting interests of the military, the government and the scientific imperative affected how the military volunteer was perceived

    INVESTIGATING THE PERCEPTION OF EXPATRIATES TOWARDS IMMIGRATION SERVICE QUALITY IN SHARJAH, UNITED ARAB EMIRATES THROUGH MIXED METHOD APPROACH

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    The public sectors in UAE are under immense pressure to demonstrate that their services are customer-focused and that continuous performance improvement is being delivered. The United Arab Emirates is a favoured destination for expatriates due to its own citizens form a minority of the population and are barely represented in the private sector workforce. These highly unusual demographics confer high importance on the national immigration services. Recently, increased interest in international migration, specifically within the United Arab Emirates, has been shown both by government agencies and by the governments of industrialised countries. Given the importance of the expatriate labour force to economic stability and growth in the Emirates, this research investigates how immigration services are perceived, with the aim of contributing to their improvement, thus ultimately supporting economic growth. It proposes a service quality perception framework to improve understanding within SID of how to raise levels of service delivered to migrants and other persons directly or indirectly affected by SID services. Qualitative data were collected by means of semi-structured interviews and quantitative data by means of a questionnaire survey based on the abovementioned framework. The survey data, on the variables influencing participants’ experiences and perceptions of SID services, were subjected to statistical analysis. The framework was then used to evaluate quality of service in terms of general impressions, delivery, location, response, SID culture and behaviour. Numerical data were analysed using inferential and descriptive statistics. It was found that service quality positively influenced service behaviour and that this relationship was mediated by SID culture. This research makes an original contribution to knowledge as one of the few studies of immigration to the United Arab Emirates. By examining the workings of one immigration department, it adds to the literature on immigration departments and organisational development in developing countries. It illuminates the mechanics of immigration services and demonstrates their increasing importance to the world economy

    The role of adult and community education and training in equipping the youth with employable skills : the case of Mashashane-Maraba area of Limpopo

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    Youth unemployment is a persistent challenge in South Africa that is worsening as the percentage of especially young people that are unemployed or unemployable increases quarterly. The Province of Limpopo is ranked among rural provinces and is characterised by a significant number of economically-active youth that are either unemployed or unemployable and this has negative effects on families, communities and the nation at large. Of other initiatives, the South African government established Community Education and Training Colleges (CETCs) with an aim to up-skill school-leavers and/or mitigate the high rate of unemployment. This study therefore sought to investigate whether the ACET has up-skilled the youth of Mashashane-Maraba in the Limpopo Province. The study also investigated reasons that explain the low registration in ACET programmes by the youth in Mashashane-Maraba. An empirical inquiry using a qualitative research design was used to conduct a case study on four Community Learning Centres located in the Mashashane-Maraba area of the Limpopo Province of South Africa. The researcher sourced data from the field through one-on-one face-to-face interviews, focus group discussions, observations and document analysis. The relevant literature was reviewed on the role of ACET in equipping the youth with employable skills. Furthermore, important documents of the Department of Higher Education on ACET relevant to the study were also reviewed to obtain rich data for the study. A sample of 29 participants comprising 20 adult learners, 3 facilitators, 4 centre managers and 2 officials were purposively selected for the interviews from selected Community Education and Training Colleges in Limpopo. The theories of andragogy, dependency, transformation and empowerment were adopted and used as the foundation of the study. The results revealed that the selected community learning centres in Mashashane-Maraba offered the old general education and training certificate for adult learning programmes however, the programmes did not up-skill or impart skills to students. The fact that the ACET curriculum offered by the CET Colleges did not offer skills training, limits chances of employment to the youth; hence, most of them opted to stay at home rather than enrol for the programme. Based on the findings, the study made the following recommendations for stakeholders to improve the programmes, especially in the CET Colleges located in the Limpopo Province: • There is a need to provide proper infrastructure for community colleges and their delivery sites in order to foster distinct institutional identity; • The government should incorporate a practical aspect that focuses on imparting job skills in order to enhance employment chances for registered youth. This can reduce the social grant bill on the taxpayers; • The Adult and Community Education and Training (ACET) programmes offered by the selected Community Learning Centres in Limpopo should emphasise on practical skills in order to equip the out-of-school youth with employment or self-employment skills; and • The working conditions of the Community Education and Training Educators should be improved in order to increase their focus and commitment in the provision of skills. In conclusion, this study contributes to the knowledge in the CET sector by revealing some of the major challenges hindering the effective implementation of curriculum that focus on skills training of unemployed youths in the countryside communities. Given that unemployment is a major problem facing the youth in rural communities, the study emphasised the need for transformation of the curriculum in Community College programmes so that it includes more practical job-related skills such as plumbing, welding, building, electrical and leather works. The findings from the study could be used to ensure that programmes offered by the CET Colleges up-skill the youth so that their chances of finding employment are enhanced. However, as a case study, this investigation does not seek to over-generalise its findings bearing in mind that the conditions of the various community learning centres (CLCs) may differ from one another.Educational StudiesPh. D. (Adult Education

    'There's lots of suffering in here, but some people are suffering more': Age, Gender and the Pains of Imprisonment

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    Older offenders are the fastest growing group in the prison population in England and Wales. While most age groups of prisoners have been falling the number of prisoners over the age of 50 has continued to increase. Older prisoners have different needs to the general prison population; however, at the time of writing, the government has yet to implement a policy outlining standards of care for this group of prisoners. This thesis is the result of and nine-month long ethnography that took place in two prisons, a man's, and a woman's, in England from June 2017 to February 2018. It explores the challenges faced by older people in prison, and how this lack of policy impacted on the older prisoner population. It also examines if those difficulties were experienced equally by the older men and women or if, in a system designed for young men, there were gendered differences in the challenges they faced. The findings highlight how the older men and women suffered from three additional pains of imprisonment as a result of their incarceration: the Pains of Isolation, the Pains of Loss and the Pains of Ageing and Deteriorating Health. These additional pains, experienced by the older people, were exacerbated by a prison system that did not make any accommodation for their additional needs. However, these ageing pains of imprisonment were not felt equally by the older prisoner population. There was a gendered aspect to many of them and the older women experienced additional gendered ageing pains of imprisonment. Where possible, the older people attempted to mitigate their ageing pains of imprisonment; by forming social networks, by working, or by finding a benefit to their incarceration. However, their ability to use their limited agency was impacted by the policies of the prison regime. This thesis considered if institutional thoughtlessness assisted in understanding why older people were experiencing additional ageing pains of imprisonment; but concluded that, as a concept, institutional thoughtlessness could not sufficiently explain why these prisoners' needs were overlooked. Moving beyond institutional thoughtlessness, the thesis explores the concept of institutional ageism and how it manifests itself at a macro, meso and micro level; concluding that the ageist policies of the prison service were making the time of older people in prison more difficult and increasing their additional ageing pains of imprisonment. Moreover, when these ageist policies intersected with gender, the ageing pains of imprisonment were experienced more keenly by the older women

    Developing end-of-life care at a Portuguese nursing home through participatory action research

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    Background: Nursing homes are places where older people live and often die but little is known about the needs of those who care for them, in Portugal. Aim: to identify the needs of nursing home staff when caring for older people at the end of life; to understand the cultural nuances of providing care at the end-of-life in nursing homes; to develop, with nursing home staff, a culturally appropriate programme that meets their needs; and to plan for future development. Methods: Participatory Action Research was used to identify needs and to develop interventions, designed by the staff themselves, aimed at improving care. Up to ten nursing home staff participated in a six-cycle research process, with data collected, analysed, and used in sequential plan-act-reflect steps. Findings: The silence that surrounds a resident’s death has a severe impact on the lives of those who survive him/her. Lacking competencies in grief management, and with no emotional and relational space to express grief emotions, staff strive to manage their loss, while trying to support other residents. Acknowledging the existence of death and its impact on nursing home life made the invisibility of death and mourning visible, and interventions possible, providing closure to all. Conclusion: The impact of death and dying on nursing home life needs to be recognised. If adequately supported, nursing home staff can develop strategies to manage grief and mourning, to improve their knowledge of the residents’ needs and wishes, improve communication among staff, and ultimately improve care

    The geographies of care and training in the development of assistance dog partnerships

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    Human-assistance-dog partnerships form a significant phenomena that have been overlooked in both animal geographies and disability geographies. By focusing on one Assistance Dogs UK (ADUK) charity, ‘Dog A.I.D’., a charity that helps physically disabled and chronically ill people to train their own pets to be assistance dogs, I detail the intimate entangled lifeworlds that humans and dogs occupy. In doing so, I also dialogue between the sub-disciplinary fields of animal geographies and disability geographies, by exploring two broad thematic areas – embodiment and care. As such, this thesis examines the geographies of assistance dog partnership, the care and training practices involved, the benefits and challenges of sharing a lifeworld with a different species, and the changing relationship from a human-pet bond to a human-assistance-dog partnership. Drawing on lived experience and representations of assistance dog partnerships gathered through qualitative (and quantitative) research methods, including a survey, semi-structured interviews (face-to-face, online, and telephone), video ethnography, and magazine analysis, I contribute to research on the assistance dog partnerships and growing debates around the more-than-human nature of care. The ethnomethodological approach to exploring how training occurs between disabled human and assistance dog is also noteworthy as it centres the lively experiences of practice at work between species. The thesis is organised around interconnected themes: the intimate worlds of assistance dog partnerships, working bodies, and caring relations. These thematics allow for a geographical interpretation into the governance, spatial organisation, and representations of dog assistance partnerships. I also explore the training cultures of Dog A.I.D. whilst also spotlighting the lived experiences of training through the early stages of ‘socialisation’, ‘familiarisation’, ‘life skills training’, through to ‘task work’. Finally, the thesis focuses on the practices of care that characterise the assistance dog partnership, showing how care is provided and received by both human and nonhuman. I pay attention to the complex potentiality of the partnership, illustrating how dogs are trained to assist, but also how dogs appear to embody lively, agentic, moments of care. The thesis contributes original work which speaks to animal and disability geographies and attends to the multiple geographies of care-full cross-species lives
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