261 research outputs found

    High reliability megawatt transformer/rectifier

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    The goal of the two phase program is to develop the technology and design and fabricate ultralightweight high reliability DC to DC converters for space power applications. The converters will operate from a 5000 V dc source and deliver 1 MW of power at 100 kV dc. The power weight density goal is 0.1 kg/kW. The cycle to cycle voltage stability goals was + or - 1 percent RMS. The converter is to operate at an ambient temperature of -40 C with 16 minute power pulses and one hour off time. The uniqueness of the design in Phase 1 resided in the dc switching array which operates the converter at 20 kHz using Hollotron plasma switches along with a specially designed low loss, low leakage inductance and a light weight high voltage transformer. This approach reduced considerably the number of components in the converter thereby increasing the system reliability. To achieve an optimum transformer for this application, the design uses four 25 kV secondary windings to produce the 100 kV dc output, thus reducing the transformer leakage inductance, and the ac voltage stresses. A specially designed insulation system improves the high voltage dielectric withstanding ability and reduces the insulation path thickness thereby reducing the component weight. Tradeoff studies and tests conducted on scaled-down model circuits and using representative coil insulation paths have verified the calculated transformer wave shape parameters and the insulation system safety. In Phase 1 of the program a converter design approach was developed and a preliminary transformer design was completed. A fault control circuit was designed and a thermal profile of the converter was also developed

    IT-Supported Organizational Memory: How Will It Affect Organizational Learning?

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    The purpose of the panel is to explore the effects of IT-supported organizationalmemory systems on organizational learning in all its fonns. Single-loop le,uning makes explicit its recognition of past practice, resulting in incremental improvemeats in pcrfonnance. Double-loop learning occurs when members question underlying assumptions and lravent new practices. Both forms of learning (and Incmory modification) are essential to organizational survival, growth, and enhanced productivity. The panel will examine the effects of OMIS designs on organizationd learning from a variety of perspectives and at different levels of analysis (Le., individual, group, and organization)

    How Shall We Manage Our Journals in the Future? A Discussion of Richard T. Watson\u27s Proposals at ICIS 2004

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    Journals are the lifeblood of all academic professions, including information systems. At the 2004 International Conference on Information Systems (ICIS), Rick Watson, then President of the Association for Information Systems (AIS), presented proposals for improving IS journal management that included accrediting reviewers, creating a market for journal articles, and moving our journals to the next level of Internet sophistication. This paper reports on a panel of journal editors convened at ICIS 2005 to discuss the Watson proposals and their implications. The editors were those of the Journal of the Association for Information Systems, the Journal of MIS, and Management Information Systems Quarterly in the United States and the Journal of Information and Technology in the United Kingdom. The paper presents their views and a reply by Watson

    Framework, principles and recommendations for utilising participatory methodologies in the co-creation and evaluation of public health interventions

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    Background: Due to the chronic disease burden on society, there is a need for preventive public health interventions to stimulate society towards a healthier lifestyle. To deal with the complex variability between individual lifestyles and settings, collaborating with end-users to develop interventions tailored to their unique circumstances has been suggested as a potential way to improve effectiveness and adherence. Co-creation of public health interventions using participatory methodologies has shown promise but lacks a framework to make this process systematic. The aim of this paper was to identify and set key principles and recommendations for systematically applying participatory methodologies to co-create and evaluate public health interventions. Methods: These principles and recommendations were derived using an iterative reflection process, combining key learning from published literature in addition to critical reflection on three case studies conducted by research groups in three European institutions, all of whom have expertise in co-creating public health interventions using different participatory methodologies. Results: Key principles and recommendations for using participatory methodologies in public health intervention co-creation are presented for the stages of: Planning (framing the aim of the study and identifying the appropriate sampling strategy); Conducting (defining the procedure, in addition to manifesting ownership); Evaluating (the process and the effectiveness) and Reporting (providing guidelines to report the findings). Three scaling models are proposed to demonstrate how to scale locally developed interventions to a population level. Conclusions: These recommendations aim to facilitate public health intervention co-creation and evaluation utilising participatory methodologies by ensuring the process is systematic and reproducible

    Communicating product user reviews and ratings in interfaces for e-commerce: a multimodal approach

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    This paper describes a comparative empirical evaluation study that uses multimodal presentations to communicate review messages in an e-commerce platform. Previous studies demonstrate the effective use of multimodality in different problem domains (e.g. e-learning). In this paper, multimodality and expressive avatars are used to communicate information related to product reviews messages. The data of the reviews was opportunistically collected from Facebook and Twitter. Two independent groups of users were used to evaluate two different presentations of reviews and ratings using as a basis an experimental e- commerce platform. The control group used a text-based with emojis presentation and the experimental group used a multimodal approach based on expressive avatars. Three parameters of usability were measured. These were efficiency, effectiveness, user satisfaction, and user preference. The result showed that the two approaches performed similarly. These findings provide a basis for further experiments in which text, emojis and expressive avatars can be combine to communicate a larger volume of reviews and ratings

    The impacts of Information and Communications Technology (ICT) and E-commerce on bilateral trade flows

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    This study examines the impact of Internet and e-commerce adoption on bilateral trade flows using a panel of 21 developing- and least-developed countries and 30 OECD countries. Given the commitment of East African Community (EAC) to become the frontrunner in export-led economy across the African continent, special attention is dedicated to analyse the role of ICT and e-commerce on EAC’s export performance. The empirical results indicate that better access to the modern ICT and adoption of e-commerce applications stimulate bilateral trade flows at various levels. The study notes that the efficient use of ICT equipped with high speed internet and secured servers is a crucial milestone for unlocking the e-trade potentials for developing- and least-developed counties

    The innovation of Multiview3 for development professionals

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    The Multiview Methodology for Information Systems Development has never been a widely used or mass-market approach. It has always had a small user base, a localised approach to a global issue: coherent IS development. This paper concerns the underreported innovation of the Multiview3 methodology for Information systems analysis, design and development – specifically designed for non-specialists working in developing countries. The innovation emerged from the identification of a methodological ‘gap’ in support for non-specialists struggling with Information Systems problem structuring challenges. The Multiview3 story tells us how IS methodology can be innovated to address the needs of users. This version of Multiview is argued to be theoretically distinct from previous versions in terms of its focus (developing countries) and application (problem solving and co-learning in practice)

    Consumers’ value co-creation in sharing economy: The role of social support, consumers’ ethical perceptions and relationship quality

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    The ancient phenomenon of ‘sharing’ has become mainstream, and transformed the traditional consumer behavior due to proliferation of online sharing economy platforms. Millions of people participate in popular sharing economy platforms (SEPs) such as Airbnb and Uber. Although sharing economy research has gained interest, yet a holistic model that explains the formation of consumer value co-creation intentions on such platforms remains absent. The purpose of this study is to develop a model of the antecedents of consumers value co-creation intentions at SEPs and evaluate it empirically. Building on social support theory, relationship quality theory, value co-creation and marketing ethics literature, we propose a theoretical model that explains the formation of consumers’ value co-creation intentions. Empirical data was collected from 342 Generation Y consumers and analyzed using structural equation modeling (SEM). The results reveal that social support influences ethical perceptions, which further influences value co-creation. Ethical perceptions also influence consumers' trust, satisfaction and commitment with the SEP. However, trust and commitment do not influence value co-creation intentions. Our study contributes to the literature on sharing economy by providing a holistic model of the antecedents of consumers’ value co-creation intentions. We also detail theoretical and managerial implications
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