133 research outputs found

    A Formal, Hierarchical Design and Validation Methodology for VLSI

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    The high cost of fabricating VLSI circuits requires that they be validated, that is, shown to function correctly, before manufacture. The cost of design errors can be kept to a minimum if such validation occurs as early as possible; this is achieved by integrating validation into a hierarchical design procedure. In this thesis, a hierarchical approach to design, in which validation is performed between each pair of adjacent levels in the hierarchy, is developed. In order to adopt such an approach, a language is required for the formal description of hardware behaviour and structure. Therefore an important aspect of the development of the methodology, and a major theme of the thesis, is the development of languages to support the methodology. An enhanced version of CIRCAL, which enables large and abstract devices to be described concisely and supports formal reasoning about the behaviour of constructed systems, is presented. Specifications should accurately model the behaviour of real hardware and should be useful for design and validation; they should also be easy to write. In order to realise these goals, a number of specification techniques have been developed and a new language which enforces some of these techniques, thereby easing the specification task, is proposed. Ways in which a language may assist design have been investigated. Language constructs which restrict a designer, thereby removing some design decisions, have been developed. A simple correctness-preserving transformation is presented, illustrating another way in which a designer may be assisted by a formal language. Specification techniques play an important part in the validation task, as accurate and consistent modelling is vital in establishing the correctness of implementations. Techniques have also been developed which enable detailed implementations to be usefully compared with more abstract specifications. This is demonstrated in a large example, the specification, design and formal verification of a simple microprocessor. Finally, the concept of contextual constraints, restrictions on the environment in which a device may be placed, is introduced. A method of specifying such constraints has been developed, and it is shown that their formal treatment can provide assistance in specification, design and verification

    An Overview of the AURORA Gigabit Testbed

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    AURORA is one of five U.S. testbeds charged with exploring applications of, and technologies necessary for, networks operating at gigabit per second or higher bandwidths. AURORA is also an experiment in collaboration, where government support (through the Corporation for National Research Initiatives, which is in turn funded by DARPA and the NSF) has spurred interaction among centers of excellence in industry, academia, and government. The emphasis of the AURORA testbed, distinct from the other four testbeds, is research into the supporting technologies for gigabit networking. Our targets include new software architectures, network abstractions, hardware technologies, and applications. This paper provides an overview of the goals and methodologies employed in AURORA, and reports preliminary results from our first year of research

    The AURORA Gigabit Testbed

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    AURORA is one of five U.S. networking testbeds charged with exploring applications of, and technologies necessary for, networks operating at gigabit per second or higher bandwidths. The emphasis of the AURORA testbed, distinct from the other four testbeds, BLANCA, CASA, NECTAR, and VISTANET, is research into the supporting technologies for gigabit networking. Like the other testbeds, AURORA itself is an experiment in collaboration, where government initiative (in the form of the Corporation for National Research Initiatives, which is funded by DARPA and the National Science Foundation) has spurred interaction among pre-existing centers of excellence in industry, academia, and government. AURORA has been charged with research into networking technologies that will underpin future high-speed networks. This paper provides an overview of the goals and methodologies employed in AURORA, and points to some preliminary results from our first year of research, ranging from analytic results to experimental prototype hardware. This paper enunciates our targets, which include new software architectures, network abstractions, and hardware technologies, as well as applications for our work

    Religion as practices of attachment and materiality: the making of Buddhism in contemporary London

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    This article aims to explore Buddhism’s often-overlooked presence on London’s urban landscape, showing how its quietness and subtlety of approach has allowed the faith to grow largely beneath the radar. It argues that Buddhism makes claims to urban space in much the same way as it produces its faith, being as much about the practices performed and the spaces where they are enacted as it is about faith or beliefs. The research across a number of Buddhist sites in London reveals that number of people declaring themselves as Buddhists has indeed risen in recent years, following the rise of other non-traditional religions in the UK; however, this research suggests that Buddhism differs from these in several ways. Drawing on Baumann’s (2002) distinction between traditionalist and modernist approaches to Buddhism, our research reveals a growth in each of these. Nevertheless, Buddhism remains largely invisible in the urban and suburban landscape of London, adapting buildings that are already in place, with little material impact on the built environment, and has thus been less subject to contestation than other religious movements and traditions. This research contributes to a growing literature which foregrounds the importance of religion in making contemporary urban and social worlds

    Does religion influence entrepreneurial behaviour?

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    Religion cannot be ignored in assessing the range of cultural and institutional influences that impact on entrepreneurial activity. This article integrates key themes from sociology of religion in the context of emerging ideas about religion and entrepreneurship in order to highlight key research questions. New institutional theory is discussed as a potentially useful lens for viewing the range of means through which religious expression and institutions might support entrepreneurship. A macro-level empirical investigation of societal indicators of religious affiliation and regulation of religion alongside Global Entrepreneurship Monitor data highlights particular data correlations and mediating influences. A significant association between entrepreneurial activity and evangelical or Pentecostal Christian religious affiliation is found, along with evidence that the impact of religion on entrepreneurship is mediated through pluralism and regulation. In discussing these findings further, the article proposes a more integrated conceptual framework for understanding the link between religious drivers and entrepreneurship, alongside institutional mediation. This forms the basis for further research, focusing on individual experience rather than aggregate associations and exploring in further depth of the mediating impact of institutional arrangements

    Primordialists and Constructionists: a typology of theories of religion

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    This article adopts categories from nationalism theory to classify theories of religion. Primordialist explanations are grounded in evolutionary psychology and emphasize the innate human demand for religion. Primordialists predict that religion does not decline in the modern era but will endure in perpetuity. Constructionist theories argue that religious demand is a human construct. Modernity initially energizes religion, but subsequently undermines it. Unpacking these ideal types is necessary in order to describe actual theorists of religion. Three distinctions within primordialism and constructionism are relevant. Namely those distinguishing: a) materialist from symbolist forms of constructionism; b) theories of origins from those pertaining to the reproduction of religion; and c) within reproduction, between theories of religious persistence and secularization. This typology helps to make sense of theories of religion by classifying them on the basis of their causal mechanisms, chronology and effects. In so doing, it opens up new sightlines for theory and research
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