317 research outputs found

    Rate-splitting multiple access for non-terrestrial communication and sensing networks

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    Rate-splitting multiple access (RSMA) has emerged as a powerful and flexible non-orthogonal transmission, multiple access (MA) and interference management scheme for future wireless networks. This thesis is concerned with the application of RSMA to non-terrestrial communication and sensing networks. Various scenarios and algorithms are presented and evaluated. First, we investigate a novel multigroup/multibeam multicast beamforming strategy based on RSMA in both terrestrial multigroup multicast and multibeam satellite systems with imperfect channel state information at the transmitter (CSIT). The max-min fairness (MMF)-degree of freedom (DoF) of RSMA is derived and shown to provide gains compared with the conventional strategy. The MMF beamforming optimization problem is formulated and solved using the weighted minimum mean square error (WMMSE) algorithm. Physical layer design and link-level simulations are also investigated. RSMA is demonstrated to be very promising for multigroup multicast and multibeam satellite systems taking into account CSIT uncertainty and practical challenges in multibeam satellite systems. Next, we extend the scope of research from multibeam satellite systems to satellite- terrestrial integrated networks (STINs). Two RSMA-based STIN schemes are investigated, namely the coordinated scheme relying on CSI sharing and the co- operative scheme relying on CSI and data sharing. Joint beamforming algorithms are proposed based on the successive convex approximation (SCA) approach to optimize the beamforming to achieve MMF amongst all users. The effectiveness and robustness of the proposed RSMA schemes for STINs are demonstrated. Finally, we consider RSMA for a multi-antenna integrated sensing and communications (ISAC) system, which simultaneously serves multiple communication users and estimates the parameters of a moving target. Simulation results demonstrate that RSMA is beneficial to both terrestrial and multibeam satellite ISAC systems by evaluating the trade-off between communication MMF rate and sensing Cramer-Rao bound (CRB).Open Acces

    Basketball, culture and society in a devolved context: a qualitative analysis

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    This thesis investigates the potential of basketball as a tool for development in Scotland. It provides an original conceptual synthesis of knowledge that offers a critical narrative concerning the evolving relationship between basketball, development, and society alongside the limits and possibilities of basketball in Scotland. The study adopts the interpretivist paradigm alongside qualitative methodology. It consists of an exploratory mixed-methods approach which utilises audio-visuals, documents and reports alongside semi-structured interviews and embeds a case study design. The research comprises four empirical chapters: The Development and History of Basketball in Scotland; Grassroots Basketball in Scotland: basketballscotland; Community Basketball in Scotland: Blaze Basketball Club; and Professional Basketball in Scotland: Caledonia Gladiators Basketball Club. Findings indicate that basketball helps develop people, communities and nations through capability building processes. To generate optimal developmental outcomes through basketball, a collaborative, democratic, intentional, person-first, community-driven, needs-motivated, ground-level led system bound by connections alongside relationships, underpinned by passionate people is required. The earlier people are introduced to basketball and the longer they remain in basketball environments, the greater the potential for developmental outcomes. To maximise results, basketball in Scotland must address its main limitations: funding; lagging opportunities; participatory barriers; Scottish basketball’s disjointed community, nature, positionality, and system; alongside Scotland’s sporting culture

    A Dataset and Analysis of Open-Source Machine Learning Products

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    Machine learning (ML) components are increasingly incorporated into software products, yet developers face challenges in transitioning from ML prototypes to products. Academic researchers struggle to propose solutions to these challenges and evaluate interventions because they often do not have access to close-sourced ML products from industry. In this study, we define and identify open-source ML products, curating a dataset of 262 repositories from GitHub, to facilitate further research and education. As a start, we explore six broad research questions related to different development activities and report 21 findings from a sample of 30 ML products from the dataset. Our findings reveal a variety of development practices and architectural decisions surrounding different types and uses of ML models that offer ample opportunities for future research innovations. We also find very little evidence of industry best practices such as model testing and pipeline automation within the open-source ML products, which leaves room for further investigation to understand its potential impact on the development and eventual end-user experience for the products

    A Pedagogy of Love: reflections on 25 years of informal vocational education and training practices in the commercial fishing industry in South Africa

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    This thesis is a reflection of informal vocational education and training (IVET) practices conducted by the Researcher in the commercial fishing industry between 1995-2021. Fourteen interventions took place during this time which involved several hundred sea-going employees who are disadvantaged by low levels of literacies and low/no Internet Computer Technology connectivity. The Production Programme was chosen as the focus of study and draws upon the influence of the other thirteen programmes. The purpose of the Production Programme was to teach technical fish processing skills to the production management teams and factory hands who work in the factories on board the vessels. The programme ran for five years and evolved through three distinct generations. At the heart of this work lies the question: ‘What made these programmes successful?’ This is an intra-programmatic study and seeks to identify the pedagogical practices which promoted or confounded the efficacy of the Production Programme; and based upon this understanding how such programmes could be improved, transferred, and taken to scale. These questions are both descriptive and explorative in nature. IVET is regarded as training which takes place outside of the formal South African National Qualifications Framework. This work is relevant because approximately 80% of sea-going staff neither finish school, nor get the opportunity of Post School Education and Training by going to a university, a technical institution, or a community college. This statistic is reflected in the general population (Department of Higher Education and Training [DHET], 2022). There is a fine line between being employed and unemployed for people working at this level in the formal economy which makes this project relevant to youth or persons who are ‘not in employment, education or training’ too. This means that for most South African adults IVET presents a significant opportunity for post-school education. Therefore, it is important to answer the questions raised above to rapidly improve inclusion of the majority of South Africans into meaningful education which improves livelihoods. The Theory of Practice Architectures (TPA), from the collection of social-material practice theories, is the conceptual framework for this thesis. The smallest unit of analysis of TPA are practices which may be ‘sayings/thinkings’, ‘doings’, or ‘relatings’. These practices bundle together into practice arrangements and form practice architectures. The reason that TPA was chosen was that practices were the only data available as we (learners, managers, facilitators, and me) knew what we had said/thought or done, and we were aware of the relationships between us over the years as the fourteen interventions played out. Under conventional research circumstances data would be collected in real time, however in this project, most of the data is historical. In addition to the fundamental building blocks of TPA, the theory is embedded in a Theory of Education. There have also been contemporary enhancements to the TPA which were significant to this study, for example, the Ecologies of Practices, a Trellis of Practices which Support Professional Learning, Middle Leadership, Travelling Practices, and moves towards transformative or transgressive education using the TPA in IVET. This is empirical, qualitative research and an ethnographic case study was chosen as the research design which is a methodology particularly suited to answering both descriptive and explorative questions. Nine methods for data collection were used, namely an historical reflective narrative; two focused-group interviews; three individual interviews; four Whatsapp videos; one WhatsApp voice note; two mobisodes; ten questionnaires; 29 documents; and 16 photographs. Because this data was collected under Covid-19 pandemic conditions, two conceptions were employed to guide the generation of data under these uncertain and constrained conditions. These were firstly, the ‘methodology of chance’ which allowed for a ‘methodological agility’; and secondly, the idea of ‘information power’ which is helpful in deciding on how much data is enough. In order to be explicit concerning a key research activity, the approach and method used to review the literature is explicated. Key practices were identified in the data set and described; and then the data was analysed using heuristics provided by TPA theorists. Seven Tables of Invention were used to synthesise the data arising from these practices. An eighth Table of Invention was used to synthesise all the practices and practice arrangements characterised; and to indicate how these evolved over time and space. The data description and analysis is supported by eight Analytic Memos, a comprehensive Data Code Table and a hyperlink to a data repository which provides access to oral and video material. The findings distinguished five key practices and practice arrangements which were: Practices of the Creation of Courseware; Practices of Teaching and Learning; Practices of Assessment; Practices of Love; Practices of Management. The thesis title is reflective of the impact which love has upon the pedagogical process of IVET. Based upon the analysis and synthesis of the corpus of data, practices which either promoted or confounded the Production Programme became visible; it is these insights which inform future improvements to similar programmes. Emanating from these findings, two overarching practice architectures (PA) were identified which restrained the Production Programme in the same manner that the banks of a river restrain a river, and yet simultaneously, are changed by the river over time. These are the PA of Methodology and Methods and the PA of Maturing Ecologies of Practices. The inferences drawn from the data were achieved through the use of deductive, inductive, and abductive reasoning. My claim to new knowledge is a lamination of a practical contribution on one side of the coin, and a theoretical contribution on the other side of the coin. The PA of Methodology and Methods provides a practical mechanism to create, deliver and assess IVET. This is done by explicating the three practice architectures which constitute the overarching PA of Methodology and Methods which are, the PA of Informality; the PA of Range, and the PA of Relationality. An IVET programme constitutes Ecologies of Practices. The theoretical conception of the overarching PA of Maturing Ecologies of Practices provides a conceptual tool which enables the transferring and scaling of IVET programmes. It does this by providing theoretical indicators to establish the ‘state’ of an IVET programme as it matures over time from a pioneer state to a settler state. An IVET educator can then work towards creating a PA which is conducive for a mature ecologies of practices to form; and the programme can then be transferred and/or taken to scale, if this is desirable in the particular context. The power of my claim to new knowledge does not lie on one side or the other of the coin, but in the lamination of the practical and theoretical contributions put to use in the service of IVET. This thesis concludes with a number of theoretical and practical recommendations which are loosely grouped according to ‘sayings/thinkings’, ‘doings’ and ‘relatings’ in deference to the value of TPA to this thesis. An urgency is conveyed in these recommendations as there is an immediate need to improve the livelihoods of ordinary South Africans. One of the ways of doing this is through informal ‘education for living well’ which contributes to a ‘world worth living in’.Thesis (PhD) -- Faculty of Education, Education, 202

    Secondary school heads’ perceptions of the effectiveness of results-based management : Highglen district, Harare

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    English, Afrikaans and isiXhosa abstractsThis study aimed to explore the perceptions of secondary school heads about the effectiveness of result based management (RBM) in schools. For over a decade since its inception as a public sector management approach, the RBM system continues to encounter uptake-related problems in schools. There is not much-documented evidence about RBM effectiveness from the perspective of secondary school heads as institutional gate keepers and curators of the system at grass roots level. That constituted the problem to be addressed by this study. Research questions that guided the study sought to establish the school heads’ level of RBM awareness, its perceived applicability, perceived conditions for results-based effectiveness and strategies to improve its uptake and effectiveness. A qualitative research approach was adopted to investigate the perceptions of secondary school heads in the Highglen district, Harare. An intensive case study design involving 12 secondary school heads selected from 12 public secondary schools in Highglen was considered appropriate for this study. Qualitative research tools namely personal interviews and open-ended questionnaires were used to collect data. Analysis of the responses was done using the six-step model proposed by Creswell. Interpretation of data was done from the interpretivist world view. Empirical evidence from this study revealed that a majority of secondary school heads had a vague understanding of the meaning of the RBM system. It emerged that school heads were subjected to very limited exposure and training on RBM, hence, their limited appreciation thereof. School heads also perceived the RBM system as an extra burden because there were no benefits associated with it. At the school level, RBM was impeded by limited financial resources, lack of expertise and poor motivation. Result based evaluations and feedback lacked in schools. The appraisal form was perceived as too long and too wordy. Based on the literature review and findings, the study recommends the collaborative design of an improved result based management system. The study also recommends the use of both monetary and non-monetary incentives to improve the uptake of RBM.Die doel van die studie was om die persepsies van sekondere skoolhoofde oor die effektiwiteit van result based management (RBM) in skole te eksploreer. Vir meer as 'n dekade vanaf die begin van die opname van die result based management (resultaat gebaseerde bestuursbenadering) ondervind skole steeds probleme met die implimentering daarvan. Daar is nie veel gedokumenteerde bewyse oor die resultaat gebaseerde bestuur se effektiwiteit uit die perspektief van sekondere skoolhoofde (it is also acceptable to use skool prinsipale) as die hekwagters en kurators op voetsoolvlak.Die faktore genoem is wat gelei tot die probleem wat deur die studie aangespreek word. Die navorsingsvrae wat hierdie studie lei beoog om die skoolhoofde se vlak van bewustheid oor resultaat gedrewe bestuur RBM te eksploreer asook die aangenome aanpasbaarheid oor verskeie toestande, die effektiwiteit en die strategiee om effektiwiteit te bevorder. 'n Kwalitatiewe navorsings benadering was gebruik om die persepsies van sekondere skoolhoofde in Highglen distrik in Harare te ondersoek. Intensiewe gevalle studie waarby skoolhoofde van 12 publieke skole in Highglen was gesien as toepaslik vir die studie. Die kwalitatiewe navorsingsmiddele wat gebruik was om die die data in te samel in die studie was persoonlike onderhoude en oop vraag vraelyste. Die data was analiseer deur middel van die ses stap model soos voorgele deur Cresswell (2014:197). Die data was interpreteer deur die gebruik van die interprecitiese wereldbeskouing.Empiriese bewyse van die studie het onthul dat die meerderheid skool hoofde het 'n beperkte begrip van die resultaat gebaseerde bestuur sisteem.Dit het voorgekom asof die skoolhoofde nie voldoende opgelei of blootgestel is aan die bestuur stelsel nie, dus hul gebrek aan waardering daarvan. Skoolhoofde ervaar ook die resultaat baseerde stelsel as addisionele werk veral omdat daar geen voordeel of beloning daaraan gekoppel is nie. Op skool vlak word die stelsel beinvloed deur beperkte finansiele bronne, min of geen kundigheid en lae vlakke van motivering. Daar was 'n tekort aan resultaat gebaseerde evaluasies en terugvoer in skole. Die waarderingsvorm was gesien as te lank en woordryk. Die studie maak die aanbeveling van 'n samwerkende ontwerp van 'n bevorderde resultaat gebaseerde bestuur stelsel gebaseer op die literatuurstudie en empiriese bevindinge. Die studie beveel ook aan dat beide geldelike en nie geldelike aansporings middels gebruik moet word om die opname van resultaat gebaseerde bestuur te bevorder.Injongo yolu phando yayikukuphonononga iimbono zeenqununu zezikolo eziziisekondari malunga nokusebenza ngempumelelo kolawulo olusekelwe kwiziphumo (RBM) ezikolweni. Kwiminyaka engaphezu kweshumi ukusukela oko yasungulwayo njengendlela yokulawula icandelo likarhulumente, inkqubo ye-RBM isaqhubeka nokuhlangabezana neengxaki ezinxulumene nokuthathwa kwazo ezikolweni. Akukho bungqina bungako bubhaliweyo obumalunga neziphumo zolawulo olunempumelelo ngokwembono yeenqununu zezikolo eziziisekondari njengabagcini bamasango neziko lemfundo nabagcini benkqubo kwinqanaba elisezantsi. Oko kube yingxaki ekufuneka isonjululwe kolu phononongo. Imibuzo yophando ekhokele uphando ifuna ukuseka inqanaba leenqununu lolwazi olusekelwe kwisiphumo solawulo, ukubonwa kwayo, iimeko ezibonwayo zeziphumo ezisekelwe kwiziphumo kunye nezicwangciso zokuphucula ukuthathwa kwayo kunye nokusebenza kwayo. Indlela yophando esemgangathweni yamkelwa ukuphanda iimbono zeenqununu zezikolo eziziisekondari kwisithili saseHighglen, eHarare. Uyilo lwesifundo esinzulu esibandakanya iinqununu ezivela kwizikolo eziziisekondari zikarhulumente ezili-12 eHighglen lwabonwa lufanelekile kolu phando. Izixhobo zophando ezisemgangathweni ezizezi, udliwano-ndlebe lomntu siqu kunye noluhlu lwemibuzo oluvulekileyo lwasetyenziswa ukuqokelela idatha. Uhlalutyo lweempendulo lwenziwa kusetyenziswa imodeli yamanyathelo amathandathu ecetywayo nguCreswell (2014: 197). Ukutolikwa kwedatha kwenziwa kwimboniselo yehlabathi yokutolika. Ubungqina obubambekayo kolu phando bubonise ukuba uninzi lweenqununu zezikolo eziziisekondari bezinokuqonda okungacacanga kwentsingiselo yenkqubo yolawulo esekelwe kwiziphumo. Kwaye kwavela ukuba iinqununu zifumene ulwazi oluncinane kakhulu noqeqesho kulawulo olusekelwe kwiziphumo yiloo nto zibangela ukuthakazelelwa kwazo oko. Iinqununu nazo zabona inkqubo yolawulo esekelwe kwiziphumo njengomthwalo ongaphezulu kuba bekungekho nzuzo enxulumene nayo. Kwinqanaba lesikolo, ulawulo olusekelwe kwiziphumo lwaluthintelwa yimithombo yemali enyiniweyo, ukunqongophala kobuchule kunye nenkuthazo ephantsi. Iimvavanyo ezisekelwe kwiziphumo kunye nengxelo yokunika ingxelo ibinqongophele ezikolweni. Ifom yovavanyo yabonwa njengende kakhulu kwaye inamagama kakhulu. Ngokusekwe kuphononongo loncwadi kunye neziphumo zobungqina, uphononongo lucebisa uyilo lwentsebenziswano lwenkqubo yolawulo esekelwe kwiziphumo eziphuculweyo. Uphononongo lukwacebisa ukusetyenziswa kwenkuthazo yemali nengeyiyo eyemali ukuphucula ukuthathwa kolawulo olusekelwe kwiziphumo.Educational Leadership and ManagementPh. D. (Education Management
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