5,748 research outputs found

    Recognition of animated icons by elementary‐aged children

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    This paper describes a study to investigate the recognizability of and preference for animated icons by elementary‐aged aged children. Fourteen typical computer‐related tasks (e.g., copy, move) were viewed by 60 school‐children in two iconic formats: animated and static. The content of the icons and the computer process or action they mimicked were drawn from a previous study in which a similar group of children was asked to depict gesturally their interpretation of the 14 tasks. Results indicated that the animated version of the icons was more recognizable and that the children greatly preferred the animated icons over the static icons. Implications for the design of enhanced user‐interfaces for children are noted

    Teaching models and local‐area networks

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    The thesis of this paper is that new advances in both microtechnology and LAN technology can now provide teachers with flexible and exciting instructional tools which allow for a powerful integration of teaching model, curriculum content and technology. The first section describes some of the current applications of school‐based LANs. The second section discusses various teaching models, and describes an in‐depth example of how a teacher may go about providing instruction by combining a LAN and these models. The third section addresses the feasibility of such an instructional approach

    Raising the Datagram API to Support Transport Protocol Evolution

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    Some application developers can wield huge resources to build new transport protocols, for these developers the present UDP Socket API is perfectly fine. They have access to large test beds and sophisticated tools. Many developers do not have these resources. This paper presents a new high-level Datagram API that is for everyone else, this has an advantage of offering a clear evolutionary path to support new requirements. This new API is needed to move forward the base of the system, allowing developers with limited resources to evolve their applications while accessing new network services

    All-Optical Modulation in a Silicon Waveguide Based on a Single-Photon Process

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    All-optical, low-power modulation is a major goal in photonics. Because of their high mode-field concentration and ease of manufacturing, nanoscale silicon waveguides offer an intriguing platform for photonics. So far, all-optical modulators built with silicon photonic circuits have relied on either two-photon absorption or the Kerr effect. Both effects are weak in silicon, and require extremely high (~5 W) peak optical power levels to achieve modulation. Here, we describe an all-optical Mach-Zehnder modulator based on a single-photon absorption (SPA) process, fabricated entirely in silicon. Our SPA modulator is based on a process by which a single photon at 1.55 mum is absorbed and an apparently free-carrier-mediated process causes an index shift in silicon, even though the photon energy does not exceed that of silicon's bandgap. We demonstrate all-optical modulation with a gate response of 1deg/mW at 0.5 Gb/s. This is over an order of magnitude more responsive than typical previously demonstrated devices. Even without resonant enhancement, further engineering may enable all optical modulation with less than 10 mW of gate power required for complete extinction, and speeds of 5 Gb/s or higher

    Exploring employer behaviour in relation to Investors in People

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    "This report explores employer behaviour in relation to choices they make about Investors in People (IIP) accreditation in order for the future IIP strategy to ensure IIP is relevant, adds value to employers and tackles any barriers to successful delivery. The research focuses on the decision-making processes and experiences of three key groups of employers: employers that have held IIP accreditation for a number of years; employers who previously held IIP accreditation but have let this lapse; and employers who committed to gaining IIP accreditation but subsequently did not to go through the assessment process" - page 1

    Evolution of vorticity and enstrophy in the intracluster medium

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    Turbulence generated by large-scale motions during structure formation affects the evolution of the thermal and non-thermal components of the intracluster medium. As enstrophy is a measure of the magnitude of vorticity, we study the generation and evolution of turbulence by analysing the Lagrangian history of enstrophy. For this purpose we combine cosmological simulations carried out with the ENZO-code with our Lagrangian post-processing tool CRaTer. This way we are able to quantify the individual source terms of enstrophy in the course of the accretion of groups onto galaxy clusters. Here we focus on the redshift range from z=1z=1 to z=0z=0. Finally, we measure the rate of dissipation of turbulence and estimate the resulting amplification of intracluster magnetic fields. We find that compressive and baroclinic motions are the main sources of enstrophy, while stretching motions and dissipation affect most of the ensuing enstrophy evolution. The rate of turbulent dissipation is able to sustain the amplification of intracluster magnetic fields to observed levels.Comment: 14 pages, 17 Figures, accepted for publication in MNRA

    High-Q optical resonators in silicon-on-insulator-based slot waveguides

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    This letter describes the design, fabrication and characterization of high-Q oval resonators based on slot waveguide geometries in thin silicon-on-insulator material. Optical quality factors of up to 27 000 were measured in such filters, and we estimate losses of –10 dB/cm in the slotted waveguides on the basis of our resonator measurements. Such waveguides enable the concentration of light to very high optical fields within nanoscale dimensions, and show promise for the confinement of light in low-index material with potential applications for optical modulation, nonlinear optics and optical sensing

    Neural Network Based Models for Efficiency Frontier Analysis: An Application to East Asian Economies' Growth Decomposition

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    There has been a long tradition in business and economics to use frontier analysis to assess a production unit’s performance. The first attempt utilized the data envelopment analysis (DEA) which is based on a piecewise linear and mathematical programming approach, whilst the other employed the parametric approach to estimate the stochastic frontier functions. Both approaches have their advantages as well as limitations. This paper sets out to use an alternative approach, i.e. artificial neural networks (ANNs) for measuring efficiency and productivity growth for seven East Asian economies at manufacturing level, for the period 1963 to 1998, and the relevant comparisons are carried out between DEA and ANN, and stochastic frontier analysis (SFA) and ANN in order to test the ANNs’ ability to assess the performance of production units. The results suggest that ANNs are a promising alternative to traditional approaches, to approximate production functions more accurately and measure efficiency and productivity under non-linear contexts, with minimum assumptions.total factor productivity, neural networks, stochastic frontier analysis, DEA, East Asian economies

    Rare Earths and the Balance Problem: How to Deal with Changing Markets?

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    The balance between the market demand and the natural abundance of the rare-earth elements (REEs) in ores, often referred to as the Balance Problem (or the Balancing Problem), is a major issue for REE suppliers. The ideal situation is a perfect match between the market demand for and the production of REEs, so that there are no surpluses of any of the REEs. This means that the rare-earth industry must find new uses for REEs that are available in excess and search for substitutes for REEs that have either limited availability or are high in demand. We present an overview of the trends in the applications for the different REEs and show that the demand for REEs for use in magnets, catalysts, and alloys is still increasing, while the application of REEs in polishing agents, glass, and ceramics are stable. On the other hand, the use of REEs in nickel–metal-hydride (NiMH) batteries and lamp phosphors is decreasing. These changes in the REE market have an influence on the Balance Problem, because the REEs that can be recycled from fluorescent lamps, cathode-ray tubes (CRTs), and NiMH batteries have to be at least partly reused in other applications. Magnesium and aluminum alloys offer an opportunity to mitigate the Balance Problem caused by these changes in the REE market. This is illustrated for REEs that can be recycled from fluorescent-lamp phosphor waste, CRT phosphors, and NiMH batteries. At present, five REEs (Nd, Eu, Tb, Dy, and Y) are being considered as very critical by Europe, the United States, and Japan, but we forecast that in the medium term, only neodymium will remain a critical REE. This paper discusses the relationship between criticality and the Balance Problem and shows how this relationship influences the market for specific REEs.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No 680629 (REMAGHIC: New Recovery Processes to produce Rare Earth-Magnesium Alloys of High Performance and Low Cost) (project website: http://www.remaghic-project. eu). KB and PTJ acknowledge funding from the European Community’s Seventh Framework Programme ([FP7/2007–2013]) under Grant Agreement No. 607411 (MC-ITN EREAN: European Rare Earth Magnet Recycling Network) (project website of EREAN: http:// www.erean.eu). Paul McGuiness (Sciencewriter.si, Slovenia) is acknowledged for the drawing of the figures
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