13,493 research outputs found

    Analysis of reliable deployment of TDOA local positioning architectures

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    .Local Positioning Systems (LPS) are supposing an attractive research topic over the last few years. LPS are ad-hoc deployments of wireless sensor networks for particularly adapt to the environment characteristics in harsh environments. Among LPS, those based on temporal measurements stand out for their trade-off among accuracy, robustness and costs. But, regardless the LPS architecture considered, an optimization of the sensor distribution is required for achieving competitive results. Recent studies have shown that under optimized node distributions, time-based LPS cumulate the bigger error bounds due to synchronization errors. Consequently, asynchronous architectures such as Asynchronous Time Difference of Arrival (A-TDOA) have been recently proposed. However, the A-TDOA architecture supposes the concentration of the time measurement in a single clock of a coordinator sensor making this architecture less versatile. In this paper, we present an optimization methodology for overcoming the drawbacks of the A-TDOA architecture in nominal and failure conditions with regards to the synchronous TDOA. Results show that this optimization strategy allows the reduction of the uncertainties in the target location by 79% and 89.5% and the enhancement of the convergence properties by 86% and 33% of the A-TDOA architecture with regards to the TDOA synchronous architecture in two different application scenarios. In addition, maximum convergence points are more easily found in the A-TDOA in both configurations concluding the benefits of this architecture in LPS high-demanded applicationS

    Balancing the urban stomach: public health, food selling and consumption in London, c. 1558-1640

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    Until recently, public health histories have been predominantly shaped by medical and scientific perspectives, to the neglect of their wider social, economic and political contexts. These medically-minded studies have tended to present broad, sweeping narratives of health policy's explicit successes or failures, often focusing on extraordinary periods of epidemic disease viewed from a national context. This approach is problematic, particularly in studies of public health practice prior to 1800. Before the rise of modern scientific medicine, public health policies were more often influenced by shared social, cultural, economic and religious values which favoured maintaining hierarchy, stability and concern for 'the common good'. These values have frequently been overlooked by modern researchers. This has yielded pessimistic assessments of contemporary sanitation, implying that local authorities did not care about or prioritise the health of populations. Overly medicalised perspectives have further restricted historians' investigation and use of source material, their interpretation of multifaceted and sometimes contested cultural practices such as fasting, and their examination of habitual - and not just extraordinary - health actions. These perspectives have encouraged a focus on reactive - rather than preventative - measures. This thesis contributes to a growing body of research that expands our restrictive understandings of pre-modern public health. It focuses on how public health practices were regulated, monitored and expanded in later Tudor and early Stuart London, with a particular focus on consumption and food-selling. Acknowledging the fundamental public health value of maintaining urban foodways, it investigates how contemporaries sought to manage consumption, food production waste, and vending practices in the early modern City's wards and parishes. It delineates the practical and political distinctions between food and medicine, broadly investigates the activities, reputations of and correlations between London's guild and itinerant food vendors and licensed and irregular medical practitioners, traces the directions in which different kinds of public health policy filtered up or down, and explores how policies were enacted at a national and local level. Finally, it compares and contrasts habitual and extraordinary public health regulations, with a particular focus on how perceptions of and actual food shortages, paired with the omnipresent threat of disease, impacted broader aspects of civic life

    The influence of blockchains and internet of things on global value chain

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    Despite the increasing proliferation of deploying the Internet of Things (IoT) in global value chain (GVC), several challenges might lead to a lack of trust among value chain partners, e.g., technical challenges (i.e., confidentiality, authenticity, and privacy); and security challenges (i.e., counterfeiting, physical tempering, and data theft). In this study, we argue that Blockchain technology, when combined with the IoT ecosystem, will strengthen GVC and enhance value creation and capture among value chain partners. Thus, we examine the impact of Blockchain technology when combined with the IoT ecosystem and how it can be utilized to enhance value creation and capture among value chain partners. We collected data through an online survey, and 265 UK Agri-food retailers completed the survey. Our data were analyzed using structural equation modelling (SEM). Our finding reveals that Blockchain technology enhances GVC by improving IoT scalability, security, and traceability when combined with the IoT ecosystem. Which, in turn, strengthens GVC and creates more value for value chain partners – which serves as a competitive advantage. Finally, our research outlines the theoretical and practical contribution of combining Blockchain technology and the IoT ecosystem

    The company she keeps : The social and interpersonal construction of girls same sex friendships

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    This thesis begins a critical analysis of girls' 'private' interpersonal and social relations as they are enacted within two school settings. It is the study of these marginal subordinated worlds productivity of forms of femininity which provides the main narrative of this project. I seek to understand these processes of (best) friendship construction through a feminist multi-disciplinary frame, drawing upon cultural studies, psychoanalysis and accounts of gender politics. I argue that the investments girls bring to their homosocial alliances and boundary drawing narry a psychological compulsion which is complexly connected to their own experiences within the mother/daughter bond as well as reflecting positively an immense social debt to the permissions girls have to be nurturant and ; negatively their own reproduction of oppressive exclusionary practices. Best friendship in particular gives girls therefore, the experience of 'monogamy' continuous of maternal/daughter identification, reminiscent of their positioning inside monopolistic forms of heterosexuality. But these subcultures also represent a subversive discontinuity to the public dominance of boys/teachers/adults in schools and to the ideologies and practices of heterosociality and heterosexuality. By taking seriously their transmission of the values of friendship in their chosen form of notes and diaries for example, I was able to access the means whereby they were able to resist their surveillance and control by those in power over them. I conclude by arguing that it is through a recognition of the valency of these indivisiblly positive and negative aspects to girls cultures that Equal Opportunities practitioners must begin if they are serious about their ambitions. Methods have to be made which enable girls to transfer their 'private' solidarities into the 'public' realm, which unquestionably demands contesting with them the causes and consequences of their implication in the divisions which also contaminate their lives and weaken them

    Vulnerability, decision-making and the protection of prisoners in Scotland and England

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    Vulnerable and protection prisoners currently make up a sizeable proportion of the prison populations in England and Scotland, and designated physical space to house them, an approach that has developed significantly in both countries since the 1960s, remains under studied. Within research on prisons, vulnerability has been predominantly associated with risks to the self, for example, mental health problems, self-harm and suicide, internal vulnerabilities that prisoners either bring into an establishment or which are a consequence of the stressors of prison life. This literature further tends to focus on certain categories of prisoner, namely those who have committed sexual crimes. This framing of vulnerability in prison means academic research typically studies vulnerability as a settled status, and there has been a move away from exploring meanings, experiences and determinations of vulnerability as these arise and change at different points of a person’s journey through prison. This study addresses these gaps by sharing the perspectives directly from those at risk of victimization in prison as well as from those in charge of deciding who will get protection from risks. The focus is on prisoner and staff decisions to relocate to protective housing (vulnerable prisoner units (VPU) in England and protection halls in Scotland). This research utilised qualitative methods, interviewing staff (13) involved in designating or managing vulnerability in prison as well as prisoners (23) who had been identified as needing protective housing. The research was conducted in one prison in England and two prisons in Scotland. It highlights the significant levels of victimization, trauma and fear experienced by prisoner research participants, and in doing so complicates prevailing ideas of vulnerability in prison. The findings chapters show: staff perspectives on what counts as a valid basis of vulnerability and therefore how it is managed and to some extent rationed (Chapter 5); the importance of journeys into and through prisons which shape and intensify experiences of vulnerability (Chapter 6); the perspectives of prisoners housed in a VPU in England which reinforced the idea that vulnerability is fluid and that there are some common factors affecting decisions to relocate from mainstream wings, but ultimately each decision is situated in the personal circumstances of an individual (Chapter 7); the perspectives of prisoners housed in protection halls in Scotland highlighting the factors that influence decisions to seek out or resist protective accommodation where, like England, common factors influenced decisions but were situated in highly individual circumstances (Chapter 8), and how these feelings were managed. The conclusion (Chapter 9) summarises key findings and calls for a sociology of the vulnerable prisoner (building on a conceptualisation of vulnerability in Chapter 3) to understand not only how they navigate risk from others and the prison itself, but how they make sense of their newly acquired yet further stigmatized identity. Finally, it sets out some implications and suggestions for policy based on its new contribution to a sociology of vulnerability

    Adaptive task selection using threshold-based techniques in dynamic sensor networks

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    Sensor nodes, like many social insect species, exist in harsh environments in large groups, yet possess very limited amount of resources. Lasting for as long as possible, and fulfilling the network purposes are the ultimate goals of sensor networks. However, these goals are inherently contradictory. Nature can be a great source of inspiration for mankind to find methods to achieve both extended survival, and effective operation. This work aims at applying the threshold-based action selection mechanisms inspired from insect societies to perform action selection within sensor nodes. The effect of this micro-model on the macro-behaviour of the network is studied in terms of durability and task performance quality. Generally, this is an example of using bio-inspiration to achieve adaptivity in sensor networks
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