3,444 research outputs found

    Improving the Scalability of DPWS-Based Networked Infrastructures

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    The Devices Profile for Web Services (DPWS) specification enables seamless discovery, configuration, and interoperability of networked devices in various settings, ranging from home automation and multimedia to manufacturing equipment and data centers. Unfortunately, the sheer simplicity of event notification mechanisms that makes it fit for resource-constrained devices, makes it hard to scale to large infrastructures with more stringent dependability requirements, ironically, where self-configuration would be most useful. In this report, we address this challenge with a proposal to integrate gossip-based dissemination in DPWS, thus maintaining compatibility with original assumptions of the specification, and avoiding a centralized configuration server or custom black-box middleware components. In detail, we show how our approach provides an evolutionary and non-intrusive solution to the scalability limitations of DPWS and experimentally evaluate it with an implementation based on the the Web Services for Devices (WS4D) Java Multi Edition DPWS Stack (JMEDS).Comment: 28 pages, Technical Repor

    The Drama of Fishing Commons: Cournot-Nash Model and Cooperation

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    Cournot-Nash model; drama of the commons; cooperation; game theory; fishing effort.

    Towards entrepreneurial universities : barriers, facilitators, and best practices in Bulgarian and Portuguese universities

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    Purpose: Тhe main objective of this research is to investigate barriers, facilitators and best practices in the transformation of Bulgarian and Portuguese universities into entrepreneurial universities. Design/Methodology/Approach: This study relies on a survey among experts in the field to identify barriers, facilitators and best practices in the transformation of Bulgarian and Portuguese universities into entrepreneurial universities. Findings: The research findings demonstrate that there are both internal and external barriers and facilitators of the entrepreneurial transformation of universities in Bulgaria and Portugal and reveals the relative importance of the various internal and external factors. The study describes several best practices in the transformation towards an entrepreneurial university adopted at Sofia University “St. Kliment Ohridski” and ISCTE-IUL. Practical Implications: This research raises awareness of the internal challenges to making Bulgarian and Portuguese universities more entrepreneurial as well as of factors that may facilitate the process of transformation and the need to strengthen entrepreneurship ecosystem at these universities. Policy makers should devote special attention to external barriers to the transformation and especially to the need for more appropriate legal framework and more state funding. Originality/Value: The study highlights that the relative importance of the various internal and external factors is context specific.peer-reviewe

    Creativity and innovation: A contribution of behavioral economics

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    Innovation in products and services is seen by scholars, by specialized media in management, and by some managers as the main currency in modern economies. This is because it allows high average market profits, fame for innovators, or brand growth, for example. However, in practice, most managers still treat innovation as a secondary issue on their agendas. This problem results from the inability of market professionals to analyze people inside and outside their companies. It is not possible to develop innovative products in a systematic way without treating this point effectively. Moreover, in this process, creativity is a necessary, but not necessarily sufficient, condition to be fulfilled and requires behavioral transformation. In this context, it is believed that behavioral economics can make a sufficient contribution in the form of an analytical marketing tool by offering an analysis closer to human beings' reality, and, thus, allow a better understanding of people's behavior in the process of innovation in the market

    Associations of physical activity with driving-related cognitive abilities in older drivers: an exploratory study

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    The purpose of this study was to examine the associations between physical activity and driving-related cognitive abilities of older drivers. Thirty-eight female and male drivers ages 61 to 81 years (M = 70.2, SD = 5.0) responded to the International Physical Activity Questionnaire and were assessed on a battery of neuropsychological tests, which included measures of visual attention, executive functioning, mental status, visuospatial ability, and memory. A higher amount of reported physical activity was significantly correlated with better scores on tests of visual processing speed and divided visual attention. Higher amounts of physical activity was significantly associated with a better composite score for visual attention, but its correlation with the composite score for executive functioning was not significant. These findings support the hypothesis that physical activity is associated with preservation of specific driving-related cognitive abilities of older adults

    Mathisson's helical motions demystified

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    The motion of spinning test particles in general relativity is described by Mathisson-Papapetrou-Dixon equations, which are undetermined up to a spin supplementary condition, the latter being today still an open question. The Mathisson-Pirani (MP) condition is known to lead to rather mysterious helical motions which have been deemed unphysical, and for this reason discarded. We show that these assessments are unfounded and originate from a subtle (but crucial) misconception. We discuss the kinematical explanation of the helical motions, and dynamically interpret them through the concept of hidden momentum, which has an electromagnetic analogue. We also show that, contrary to previous claims, the frequency of the helical motions coincides exactly with the zitterbewegung frequency of the Dirac equation for the electron.Comment: To appear in the Proceedings of the Spanish Relativity Meeting 2011 (ERE2011), "Towards new paradigms", Madrid 29 August - 2 September 201

    Rehabilitation of abandoned villages through tourism: a solution for sustainable heritage development?

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    Villages which have been abandoned during recent decades as a result of migration from rural areas constitute a serious problem which is all too common in many European countries. The aim of this paper is to examine the problem in Portugal and conduct a comparative study of four villages, set in a range of geographical and socio-economic contexts, which have been rehabilitated. These villages are associated with: different types of vernacular architecture; different types of traditional landscape; contrasting topographic contexts; and different causes of rural abandonment. The findings of this study point to the main requirements for improvement and recommendations are made for suitable developments in terms of the heritage in its broadest sense, including the surrounding landscape. Heritage character is not only important for the preservation of local identity but may also be associated with products and services which are marketed and is thus an essential factor for the socio-economic sustainability of rehabilitated villages.CIDEHUS centre and IIFA institute of Évora University , European Union FEDR, COMPETE and QREN, Foundation for Science and Technology (FCT)
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