922 research outputs found

    LIPIcs, Volume 251, ITCS 2023, Complete Volume

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    LIPIcs, Volume 251, ITCS 2023, Complete Volum

    Challenges in the Design and Implementation of IoT Testbeds in Smart-Cities : A Systematic Review

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    Advancements in wireless communication and the increased accessibility to low-cost sensing and data processing IoT technologies have increased the research and development of urban monitoring systems. Most smart city research projects rely on deploying proprietary IoT testbeds for indoor and outdoor data collection. Such testbeds typically rely on a three-tier architecture composed of the Endpoint, the Edge, and the Cloud. Managing the system's operation whilst considering the security and privacy challenges that emerge, such as data privacy controls, network security, and security updates on the devices, is challenging. This work presents a systematic study of the challenges of developing, deploying and managing urban monitoring testbeds, as experienced in a series of urban monitoring research projects, followed by an analysis of the relevant literature. By identifying the challenges in the various projects and organising them under the V-model development lifecycle levels, we provide a reference guide for future projects. Understanding the challenges early on will facilitate current and future smart-cities IoT research projects to reduce implementation time and deliver secure and resilient testbeds

    LIPIcs, Volume 261, ICALP 2023, Complete Volume

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    LIPIcs, Volume 261, ICALP 2023, Complete Volum

    Swarm electrification: A comprehensive literature review

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    In the global North, the need to decarbonize power generation is well documented and the challenges faced are endemic to the design of the electrical grids. With networks relying on centralized generation, it can be difficult to replace fossil-fuel power plants with renewable energy sources as generation may be intermittent causing grid instability when there is no ‘spinning reserve’ [1]. In parts of the global south, however, many under-electrified nations have high levels of solar irradiance. This, combined with falling prices for solar panels, is allowing for alternative paths to electrification from costly grid extensions and has resulted in grids built from the bottom up [2]. These grids can vary considerably in scale and capacity, dubbed micro-grids, nano-grids, and pico-grids. They can utilize AC, DC, or both and generally have either a centralized or distributed topology where each design has specific advantages and disadvantages [3]. Bangladesh has seen an unprecedented proliferation of small solar home systems. After performing a case study Groh et al. [4] discovered much of the generated electricity was not being utilized

    How spatial planning can enable pathways toward wildfire mitigation within the fire-prone wildland and urban interface, City of Cape Town

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    18th of April 2021, a wildfire raged through parts of the University of Cape Towns upper campus, with damage assessed at approximately R500 million. There were calls from senior leadership that UCT "will rebuild facilities". The post-disaster rhetoric of rebuilding is problematic, as we should never rebuild what was because the old geographic, economic and social position is no longer sustainable. Critical disaster management frameworks strongly advocate more emphasis on preventing disasters; without compromising the much-needed reactive qualities of the discipline. It places responsibility on spatial planning – development restrictions, land uses, building regulations, tenure boundaries, spatial layout and road patterns –as the critical juncture toward achieving long-term disaster risk reduction. Due to climate change, wildfire anomalies and associated destructiveness oblige humankind to revise pieces of knowledge calibrated to conditions that no longer exist. This research responds to this call for "different ways of thinking", investigating the local merging of planning and disaster disciplines in hopes of creating new knowledge to realise longterm wildfire risk reduction within flammable Wild and Urban Interface, City of Cape Town. This qualitative dissertation collected primary data using online semi-structured interviews with local spatial planners, engineers, disaster management officials and insurance brokers. Secondary data was collected through a review of published journals; and regulations and policies from California, Victoria and Western Cape. Both data sets are used to investigate spatial planning as leverage to realise long-term wildfire risk reduction for the University of Cape Town and Spanish Farm Somerset West sites (the case studies of the dissertation). Even the best firefighting equipment will not help much during an extreme weather wildfire due to ember storms making fire breaks redundant. Fire-fighting and suppression technologies are less effective than perceived during wildfire extreme weather events. When it comes to traditional wildfire disaster measures such as prescribed burnings and alien vegetation removal – locally, these mitigation techniques are well established. However, the study found that disaster management respondents and best practice policy analysis, local and abroad, unanimously agree that focus must be placed on protecting urban structures for overall wildfire risk reduction. The study found that local planners and disaster management officials rarely collaborate on wildfire disaster matters due to misaligned goals and ideals. In the context of climate change, the study found that the local zoning scheme needs an overlay zone dedicated fully to wildfire mitigation, as local overlays have the unique ability to guide development in a potential "fire-safe manner". Within the City of Cape Town, spatial planning has the unique potential to realise this focus through an amended provincial zoning scheme. The study proposes a Western Cape veld and forest fire management overlay zone that demarcates high-fire risk regions on the urban edge, pre and post-development. The proposed overlay imposes restrictions on these sites to bypass "rebuilding" unsustainably and initiate "build back better" post disaster. This theorises a wildfireresilient City of Cape Town wild land urban interface. The study employs this proposed fire-specific overlay zone over the projects case studies (UCT and Spanish Farm) – to show how it could potentially mitigate wildfire risk in these flammable sites. The basis of this idea is formed from a cross-contextual analysis of Victoria, California and Western Cape regulation; and from the insights of planning, engineer, wildfire disaster management and insurance industry respondents from the Western Cape region

    A multiple method approach: case studies of multiple nongovernmental development organisations in Zambia

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    The delivery of community-based international development programmes by local nongovernmental organisations in Zambia is now reaching the third generation of young people. Many of the first generation of children, once participants of community programmes, now manage the implementation process of those programmes. This sector integrates sport with programme delivery in Zambia to advance the life prospects of young people. In this field of sport and international development the development practices within local nongovernmental organisations in Zambia has received limited attention in research. The aim of this research is to explore the practices of development underway within these local nongovernmental organisations in Zambia. The perspectives of development as freedom and capability and humanness and personhood inform the approach taken by this research to explore local development activities and practices. These perspectives are understood from wider international development literature (Sen, 1999; Hoffmann and Metz, 2017) and emergent literature in the field of sport and international development (Svensson and Levine, 2017; Mwaanga and Adeosun, 2020). Sen (1999) offers this research the lens of poverty as depriving people of what they would otherwise have the capability to achieve while Hoffmann and Metz (2017) offer a series of virtues one must exercise to qualify as an ethical being according to the perspective of humanness and personhood which is otherwise known as African ubuntu philosophy. Svensson and Levine (2017) enable the research to frame development activity that uses sport and physical activity according to the capability approach while Makuku’s (2013) analysis of Shalapo Canicandala, a well-known novel by Simon Mwansa Kapwepwe (1967), effectively lists ubuntu values long practiced by indigenous tribespeople of Zambia which this research applies to explore findings. The research used a qualitative approach to gather empirical data about local development practitioners’ experiences working for local nongovernmental organisaitons in Zambia. Data were mainly collected from one round of interviews with 15 development practitoners. Further data were gathered by engaging local practitioners in creative methods of creative writing, photography, and voice recordings. Interviews were interpreted with thematic analysis with trustworthiness achieved through membeing checking. The findings suggest that local development practitioners believe local nongovernmental organisations promote community development effectively and that they do so through a wide range of activities and processes which enable such promotion of community development. The research findings are presented as activities participants listed as essential to their organisations function which in general terms included organisation background, programmes, programme design and implementation, leadership, partnerships, Covid-19, and international voltuneering. Thematic analysis of findings prompted a discussion of precise themes featuring within these organisaiton functions as follows: international volunteers (religion, family values, dress codes, child safeguarding, problem-solving), organisation partnerships (community schools, government departments, universities, sporting bodies), programme design (Sport in Aciton, NOWSPAR, Response Network), programme implementation (dignity, feminism, civic/political leaders, life skills development), traditional games (HIV/AIDS education, male patriarchy, declining interest), social enterprise activity (Covid-19 as catalyst, Zoca, income generation, opportunities to value), international partnerships (independent female choice, social change and knowledge exchange, potential for social change, competing values), and organisation communications (transparent internal communications, effective stakeholder communication, independent stakeholder communication). The original contributions made by this thesis to knowledge include contributions to theory, methodology, context, and practice. It contributes to theory development by applying the development as freedom and capability and development as humanness and personhood perspective to empirical findings drawn from community development activities underway in the context of Zambia. The thesis offers a contribution to methodology by applying creative methods like creative writing, photography, and voice recording which align with perspectives offered by postcoloinial theorists of development. An original contribution is made to context with the research gathering rich empirical data relevant to the national context of Zambia, the context of the local nongovernment organisations explored as case by the thesis, and community contexts where these organisations work. Finally, the thesis contributes to practice with nuanced understandings of development stakeholders involved in partnership working in the sport and international development sector of Zambia

    Analysing and Reducing Costs of Deep Learning Compiler Auto-tuning

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    Deep Learning (DL) is significantly impacting many industries, including automotive, retail and medicine, enabling autonomous driving, recommender systems and genomics modelling, amongst other applications. At the same time, demand for complex and fast DL models is continually growing. The most capable models tend to exhibit highest operational costs, primarily due to their large computational resource footprint and inefficient utilisation of computational resources employed by DL systems. In an attempt to tackle these problems, DL compilers and auto-tuners emerged, automating the traditionally manual task of DL model performance optimisation. While auto-tuning improves model inference speed, it is a costly process, which limits its wider adoption within DL deployment pipelines. The high operational costs associated with DL auto-tuning have multiple causes. During operation, DL auto-tuners explore large search spaces consisting of billions of tensor programs, to propose potential candidates that improve DL model inference latency. Subsequently, DL auto-tuners measure candidate performance in isolation on the target-device, which constitutes the majority of auto-tuning compute-time. Suboptimal candidate proposals, combined with their serial measurement in an isolated target-device lead to prolonged optimisation time and reduced resource availability, ultimately reducing cost-efficiency of the process. In this thesis, we investigate the reasons behind prolonged DL auto-tuning and quantify their impact on the optimisation costs, revealing directions for improved DL auto-tuner design. Based on these insights, we propose two complementary systems: Trimmer and DOPpler. Trimmer improves tensor program search efficacy by filtering out poorly performing candidates, and controls end-to-end auto-tuning using cost objectives, monitoring optimisation cost. Simultaneously, DOPpler breaks long-held assumptions about the serial candidate measurements by successfully parallelising them intra-device, with minimal penalty to optimisation quality. Through extensive experimental evaluation of both systems, we demonstrate that they significantly improve cost-efficiency of autotuning (up to 50.5%) across a plethora of tensor operators, DL models, auto-tuners and target-devices
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