54,273 research outputs found

    Stellar spectrum classifier

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    Stellar classification is accomplished by correlating holograms of classified spectra with the Fourier transform of the spectral images to be classified

    Digital frequency discriminator

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    Frequency discriminator has five integrated circuit chips interconnected to provide a divide function, exclusive OR function, phase shifting, and holding so that a single binary output signal results. The state of the binary signal indicates which one of the two input signals has a lower frequency than the other

    Electronic frequency discriminator

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    Digital comparator permits discrimination at accuracy of reference frequency. The compare circuit is a shift register element

    Digital frequency discriminator Patent

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    Describing frequency discriminator using digital logic circuits and supplying single binary output signa

    Project:Filter - using applied games to engage secondary schoolchildren with public policy

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    Applied games present a twenty-first-century method of consuming information for a specific purpose beyond pure entertainment. Objectives such as awareness and engagement are often used as intended outcomes of applied games in alignment with strategic, organizational, or commercial purposes. Applied games were highlighted as an engagement-based outcome to explore noPILLS, a pan-European policy research project which presented policy pointers and suggested methods of interventions for reducing micropollution within the wastewater treatment process. This paper provides an assessment of a video game which was developed for the purpose of public engagement with policy-based research. The video game, Project:Filter, was developed as a means of communicating noPILLS to secondary school children in Scotland as part of a classroom-based activity. Knowledge development and engagement were identified using Interpretative Phenomenological Analysis to evidence topical awareness, depth of understanding, and suggested methods of intervention. Analysis of observations also provided insights into challenges surrounding logistics, pedagogy, social interactions, learning, and gender as contributing factors to the schoolchildren’s experiences of Project:Filter. The intention of this paper is two-fold: firstly, to provide an example of developing video games from policy-based research; and secondly, to suggest methods of phenomenological assessment for identifying play-based engagement

    Evaluation of a prototype interface for structured document retrieval

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    Document collections often display either internal structure, in the form of the logical arrangement of document components, or external structure, in the form of links between documents. Structured document retrieval systems aim to exploit this structural information to provide users with more effective access to structured documents. To do this, the associated interface must both represent this information explicitly and support users in their browsing behaviour. This paper describes the implementation and user-centred evaluation of a prototype interface, the RelevanceLinkBar interface. The results of the evaluation show that the RelevanceLinkBar interface supported users in their browsing behaviour, allowing them to find more relevant documents, and was strongly preferred over a standard results interface

    Micro-Arcsecond Radio Astrometry

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    Astrometry provides the foundation for astrophysics. Accurate positions are required for the association of sources detected at different times or wavelengths, and distances are essential to estimate the size, luminosity, mass, and ages of most objects. Very Long Baseline Interferometry at radio wavelengths, with diffraction-limited imaging at sub-milliarcsec resolution, has long held the promise of micro-arcsecond astrometry. However, only in the past decade has this been routinely achieved. Currently, parallaxes for sources across the Milky Way are being measured with ~10 uas accuracy and proper motions of galaxies are being determined with accuracies of ~1 uas/y. The astrophysical applications of these measurements cover many fields, including star formation, evolved stars, stellar and super-massive black holes, Galactic structure, the history and fate of the Local Group, the Hubble constant, and tests of general relativity. This review summarizes the methods used and the astrophysical applications of micro-arcsecond radio astrometry.Comment: To appear in Annual Reviews of Astronomy and Astrophysics (2014
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