13 research outputs found

    Secure interoperation of wireless technologies

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    Tremendous emphasis has been placed on wireless technologies recently and it is expected that mobile communications will become an even bigger key driver for growth and innovation in the near future. The purpose of this paper is to study the securing, development, integration and implementation of an always on, always available, and accessible from anywhere secure wireless communication environment. Our analysis of the different wireless technologies reveals that a number of obstacles have to be managed before truly transparent wireless public data consumer offering is available. Our concern revolves around the technical development and implementation efforts of integrated wireless technologies enveloped with management processes of change and evolution. Wireless technologies have influenced our daily lives and will undoubtedly continue to play a significant role in the future. This dissertation focuses on the interoperation of wireless technologies, exploring, evaluating and presenting representations of secure, fully integrated wireless environments. The purpose is to find a cost effective, open, viable, sustainable consumer orientated high data speed offering which not only adheres to basic security requirements but surpasses it. By bringing the network to the subscriber we generate an “always-on” and “always-available” solution for data requirements fulfilling an ever increasing human demand for access to resources anywhere, anytime. A background literature of various wireless technologies, techniques and value added services is provided. An approach for the securing of critical content over wireless links in chapter seven provides a basis for access by position concepts presented in chapter eight. This secure approach to location-aware mobile access control is an essential security enhancement in the integration and interoperation models illustrated in chapter nine. These models, appropriately named SWARM 1 and SWARM 2 (System for Wireless and Roaming Mobility), illustrate different approaches to achieving a secure, fully coherent, consumer orientated, wireless data communications environment.Dissertation (MSc (Computer Science))--University of Pretoria, 2003.Computer Scienceunrestricte

    Learning from Data Streams with Randomized Forests

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    Non-stationary streaming data poses a familiar challenge in machine learning: the need to obtain fast and accurate predictions. A data stream is a continuously generated sequence of data, with data typically arriving rapidly. They are often characterised by a non-stationary generative process, with concept drift occurring as the process changes. Such processes are commonly seen in the real world, such as in advertising, shopping trends, environmental conditions, electricity monitoring and traffic monitoring. Typical stationary algorithms are ill-suited for use with concept drifting data, thus necessitating more targeted methods. Tree-based methods are a popular approach to this problem, traditionally focussing on the use of the Hoeffding bound in order to guarantee performance relative to a stationary scenario. However, there are limited single learners available for regression scenarios, and those that do exist often struggle to choose between similarly discriminative splits, leading to longer training times and worse performance. This limited pool of single learners in turn hampers the performance of ensemble approaches in which they act as base learners. In this thesis we seek to remedy this gap in the literature, developing methods which focus on increasing randomization to both improve predictive performance and reduce the training times of tree-based ensemble methods. In particular, we have chosen to investigate the use of randomization as it is known to be able to improve generalization error in ensembles, and is also expected to lead to fast training times, thus being a natural method of handling the problems typically experienced by single learners. We begin in a regression scenario, introducing the Adaptive Trees for Streaming with Extreme Randomization (ATSER) algorithm; a partially randomized approach based on the concept of Extremely Randomized (extra) trees. The ATSER algorithm incrementally trains trees, using the Hoeffding bound to select the best of a random selection of splits. Simultaneously, the trees also detect and adapt to changes in the data stream. Unlike many traditional streaming algorithms ATSER trees can easily be extended to include nominal features. We find that compared to other contemporary methods ensembles of ATSER trees lead to improved predictive performance whilst also reducing run times. We then demonstrate the Adaptive Categorisation Trees for Streaming with Extreme Randomization (ACTSER) algorithm, an adaption of the ATSER algorithm to the more traditional categorization scenario, again showing improved predictive performance and reduced runtimes. The inclusion of nominal features is particularly novel in this setting since typical categorization approaches struggle to handle them. Finally we examine a completely randomized scenario, where an ensemble of trees is generated prior to having access to the data stream, while also considering multivariate splits in addition to the traditional axis-aligned approach. We find that through the combination of a forgetting mechanism in linear models and dynamic weighting for ensemble members, we are able to avoid explicitly testing for concept drift. This leads to fast ensembles with strong predictive performance, whilst also requiring fewer parameters than other contemporary methods. For each of the proposed methods in this thesis, we demonstrate empirically that they are effective over a variety of different non-stationary data streams, including on multiple types of concept drift. Furthermore, in comparison to other contemporary data streaming algorithms, we find the biggest improvements in performance are on noisy data streams.Engineers Gat

    Girl Music of the Indie Rock Persuasion: Amplifying Indie Through 2000s Girl Culture

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    The 2000s, a decade that is often considered lacking in defining culture or trends, represents a key period for the distillation of ideas about authenticity and access in North American music cultures. A liminal space between analogue distribution practices and the ubiquity of streaming services, the 2000s saw a turn towards television, film, and early internet cultures as the primary spaces of tastemaking and musical discovery. These unconventional sites challenged existing hierarchies and modes of gatekeeping that reproduced particular music genres, and rock music in particular, as the domain of straight, white masculinities. This interdisciplinary research explores the various facets of this cultural mainstreaming, excavating the central role of women, girls, and girl culture in this shift. I draw on qualitative research interviews conducted with female music supervisors, bloggers, and DJs to bolster this analysis of cultural intermediaries; each chapter of the dissertation also focuses on a different cultural site. In the first chapter, I place existing work on indie music cultures in conversation with girls’ studies scholarship on bedroom cultures to argue that an indie rock rhetoric of retreat and marginalization lacks a feminist citational politics. In the second chapter, I explore the shifting role of music supervisors as tastemakers and provide a critique of ‘fanboy auteur’ narratives. In the third chapter, I explore films released as indie crossover hits during the 2000s, connecting indie music and indie film theory but also arguing that, with more distance from the moment of indie rock’s initial cultural mainstreaming, cultural producers could camp its gender politics. In the fourth chapter, I explore girls’ music blogs from a particular music scene (New York City) as resistive sites where the exclusionary legacies of rock music criticism were challenged. In the fifth and final chapter, I explore how the 2000s also expanded physical music scenes into digital space with the meteoric rise of MP3 and file-sharing technologies that offered an important challenge to masculinist music cultures. This dissertation demonstrates that a wider cultural aversion to feminized cultural texts and practices flattens the stories we tell about 2000s indie rock — and the legacies it left behind

    The Telecommunications and Data Acquisition Report

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    In space communications, radio navigation, radio science, and ground based radio and radar astronomy, activities of the Deep Space Network and its associated Ground Communications Facility in planning, in supporting research and technology, in implementation, and in operations are reported. Also included is TDA funded activity at JPL on data and information systems and reimbursable DSN work performed for other space agencies through NASA

    A case for dialogic practice: A reconceptualisation of ‘inappropriate’ demand for and organisation of out of hours general practice services for children under five

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    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The recent expansion of general practitioner (GP) out of hours cooperatives indicates that many British GPs see this as the solution to managing out of hours work, particularly the 'problem' of 'inappropriate' demand. This thesis investigates the highly contentious subject of 'inappropriateness' of demand for out of hours GP services for children under five, and develops a methodology that allows for a reconceptualisation of the issues involved based on the beliefs, assumptions and practices of all those concerned, rather than locating the 'problem' within the province of parents alone, or within the doctor-patient relationship as a bounded system. Using a predominantly sociological and anthropological conceptual framework, the thesis draws on a synthesis of views and practice, bringing those of professionals and parents together with fieldwork observations based in the primary care centre setting. It suggests that contrary to talk about management of the 'problem' in technical, bureaucratic and medical terms, this becomes a moral issue in practice. Scientific or organisational imperatives disguise largely moral proscriptions and examples illustrate ways in which moral and emotional dimensions embedded within these social relations can conflict with particular forms of rationality. The analysis shows how organisational initiatives that fail to take account of such moral frameworks can produce unexpected and unintended consequences. The thesis illustrates the value of what is described as a dialogic process, taking account of the fluidity between voices, layers of time and space, and interchange between researcher, participants, and future audiences. The play of these issues in the rapid and extensive growth of cooperatives is discussed in the wider context of the rhetoric of consumerism and shifts in interprofessional practices and relationships. Negotiation of 'appropriate' supply of and demand for out of hours services has had a major impact on government initiatives for primary care as a whole. Thus key elements in the formation of cooperatives, originally targeted at a more narrow conceptualisation of problems, can be seen as expressing a deeper impetus for change, and serving as vehicles for more fundamental and rapid development.London NHS Executive R&D (previously, North Thames

    Reflections on contemporary medical professionalism; an exploration of medical practice as refracted in doctors’ narratives

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    Background During a period of continuing changes in society and increasing availability of medical information, publication of patients’ views on experiences of health and illness have gained greater prominence. By contrast, studies of medical perspectives have tended to concentrate on reported discontent and implications for workforce planning while leaving broader insights and concerns under-investigated. Since the applied skills of highly trained and publicly funded clinicians are vital for safe and effective delivery of the nation’s health care, it seemed important to explore new ways to consider components of medical professionalism and to set these in current NHS contexts. Rationale and fieldwork Focussing attention on the individual perspectives of NHS doctors in order to hear and understand their experiences of work was central to development of this thesis. An interpretive epistemological approach to biographical narratives as told by a group of 12 doctors drawing on 25 years of NHS experience included use of Situational Analysis Mapping to support detailed analysis of their richly informative, first-hand accounts. As knowledgeable and reflective informants with stories from diverse clinical specialties and differing personal viewpoints, their narratives produced a range of views and observations shaped by their lived experiences as clinicians. Poetic representation of sociologically-informative narrative extracts provided an effective vehicle for engaging mixed audiences and has evoked emotionally resonant reactions from doctors. Findings Strong connections between individuals’ core principles and enacted responses were evident; doctors identified preferred working practices which they believed supportive of delivery of high quality health care. Key aspects of professionalism, including professional autonomy, self-regulation and application of clinical knowledge, were challenged by progressive introduction of new working processes and regulatory mechanisms. Increased recording of clinical and administrative data for performance monitoring and achievement of targets produced reactive strategies in individuals and teams while challenging their sense of professional position or developed medical identity. Poorly performing colleagues and difficult team interactions caused much disruption while blurred ethical boundaries exposed contestable decision-making and demonstrated the limited effectiveness of external regulatory monitoring. Conclusions This research indicates that contemporary NHS doctors may experience conflict between what is expected in managed medical practice and their interpretation of best professional performance. Better understanding of these fundamental relationships could constructively contribute to reconsideration of contemporary medical professionalism and assist with progressive workforce preparation for an effective future NHS

    Advance in Composite Gels

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    In the last few decades, various composite gels have been developed. In recent years, further advances have been made in the development of novel composite gels with potential applications in various fields. This reprint offers the latest findings of composite gels by experts throughout the world
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