184 research outputs found

    Designing a virtual teacher for non-verbal children with autism: Pedagogical affordances and the influence of teacher voice

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    The prevalence of children with autism in Asia has been estimated as comparable to that in many other countries (Jeevanandam, 2009; William et al., 2005). Within this group, approximately one-third to one-half of these children will lack functional speech (Mirenda, 2003) and have severe learning difficulties. There have been recent technological developments for teaching children with autism, for example virtual worlds (Bignell, 2008) and socially intelligent agents (Dautenhahn & Werry, 2004). However, there has been relatively little research into the effectiveness of technologically supported approaches to language development for those children who are non-verbal. The Picture Exchange Communications System (PECS) is an augmentative and alternative communication (AAC) approach that has been used with children with little or no speech to develop language and communication skills. In essence the children gradually learn to communicate through exchanging pictures and symbols for desired items or outcomes. There is empirical evidence to support the value of this approach (Preston & Carter, 2009). This paper considers a technologically supported approach within this area: Computer Assisted Picture Exchange (CAPE). It examines the issue of teacher embodiment and the affordances arising from using an interactive virtual teacher avatar that responds to the child's manipulation of objects and symbols in the physical world. The paper discusses investigations to compare synthetic and natural teacher voices, and to assess their influence on the learning of communication skills by children with autism

    TDMA frame design for a prototype underwater RF communication network

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    This document is the Accepted Manuscript version of the following article: Xianhui Che, Ian Wells, Gordon Dickers, and Paul Kear, ‘TDMA frame design for a prototype underwater RF communication network’, Ad Hoc Networks, Vol. 10 (3): 317-327, first available online 23 July 2011. The version of record is available online at doi: http://dx.doi.org/10.1016/j.adhoc.2011.07.002 © 2011 Elsevier B. V. All rights reserved.Very low frequency electromagnetic communication system is used in a small scale underwater wireless sensor network for coastal monitoring purposes, as recent research has demonstrated distinct advantages of radio waves compared to acoustic and optical waves in shallow water conditions. This paper describes the detailed TDMA and packet design process for the prototype sensor system. The lightweight protocol is time division based in order to fit the unique characteristics and specifications of the network. Evaluations are based on initial beach trial as well as modeling and simulations.Peer reviewe

    Re-Evaluation of RF Electromagnetic Communication in Underwater Sensor Networks

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    Most underwater wireless networks use acoustic waves as the transmission medium nowadays, but the chances of getting much more out of acoustic modems are quite remote. Optical links are impractical for many underwater applications. Given modern operational requirements and digital communications technology, the time is now ripe for re-evaluating the role of electromagnetic signals in underwater environments. The research presented in this article is motivated by the limitations of current and established wireless underwater techniques, as well as the potential that electromagnetic waves can offer to underwater applications. A case study is presented that uses electromagnetic technology in a small-scale underwater wireless sensor network. The results demonstrate the likely effectiveness of the designated network

    TDMA frame design for a prototype underwater RF

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    Very low frequency electromagnetic communication system is used in a small scale underwater wireless sensor network for coastal monitoring purposes, as recent research has demonstrated distinct advantages of radio waves compared to acoustic and optical waves in shallow water conditions. This paper describes the detailed TDMA and packet design process for the prototype sensor system. The lightweight protocol is time division based in order to fit the unique characteristics and specifications of the network. Evaluations are based on initial beach trial as well as modeling and simulations

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

    Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

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    A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

    A Review of Parental Carrying of Young by Waterfowl

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    A review of literature reveals that published accounts of parental carrying among waterfowl are numerous and of diverse origins. Parental carrying on the back while swimming has been reliably seen in three species of swans, two sheldgeese, and at least seven species of ducks. Parental carrying of young in flight has also been reported for at least 16 species representing seven of the generally recognized waterfowl tribes. The majority of such accounts have involved carrying the young in the bill, a possibility that is somewhat substantiated by reliable observations of egg or eggshell carrying by females of several species. In addition, at least those species that regularly carry the young on the back while swimming may be preadapted to similar carrying of them while in flight. It is suggested that occasional parental carrying by either or both techniques is sufficiently probable as to warrant additional consideration and attention
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