6,183 research outputs found

    Method for predicting rotor free-wake positions and the resulting rotor blade airloads

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    Computer program has been designed and written to predict rotor free-wake positions and resulting rotor blade airloads without requiring time-consuming and tedious calculations. This program was written in FORTRAN IV for use on an IBM-360 computer

    Investigation in optimisation of accuracy with non-contact systems by influencing variable processes

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    The use of 3D scanning systems is becoming increasingly popular and an essential tool for manufacturers for inspection and measurement. With such systems being utilised on the manufacturing shop floor due to their portability and ease of use, it is no doubt that such systems are designed to address a variety of users whom, with minimal training can operate the equipment. Due to continuing demands of high-quality products there is the need for manufacturers of 3D scanning systems to develop technologies that deliver fast and accurate information. However, one of the key challenges lies not in the training of people to use the equipment, but to develop engineers who can produce traceable, accurate and precise results with a declared statement of confidence quantifying the quality of the measurement. This statement of the quality of the output results relies on employing a set of workflow actions that involve planning, capture, processing and analysis, and finally output. This paper sets out to show how the results from a set of workflow actions from different categories of 3D scanning devices affects the quality of output

    Testing the Structure of a Gaussian Graphical Model with Reduced Transmissions in a Distributed Setting

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    Testing a covariance matrix following a Gaussian graphical model (GGM) is considered in this paper based on observations made at a set of distributed sensors grouped into clusters. Ordered transmissions are proposed to achieve the same Bayes risk as the optimum centralized energy unconstrained approach but with fewer transmissions and a completely distributed approach. In this approach, we represent the Bayes optimum test statistic as a sum of local test statistics which can be calculated by only utilizing the observations available at one cluster. We select one sensor to be the cluster head (CH) to collect and summarize the observed data in each cluster and intercluster communications are assumed to be inexpensive. The CHs with more informative observations transmit their data to the fusion center (FC) first. By halting before all transmissions have taken place, transmissions can be saved without performance loss. It is shown that this ordering approach can guarantee a lower bound on the average number of transmissions saved for any given GGM and the lower bound can approach approximately half the number of clusters when the minimum eigenvalue of the covariance matrix under the alternative hypothesis in each cluster becomes sufficiently large

    Probing the cool ISM in galaxies via 21cm HI absorption

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    Recent targeted studies of associated HI absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm absorption profiles often show two distinct spectral-line components: narrow, deep lines arising from cold gas in the extended disc of the galaxy, and broad, shallow lines from cold gas close to the AGN (e.g. Morganti et al. 2011). Here, we present results from a targeted search for associated HI absorption in the youngest and most recently-triggered radio AGN in the local universe (Allison et al. 2012b). So far, by using the recently commissioned Australia Telescope Compact Array Broadband Backend (CABB; Wilson et al. 2011), we have detected two new absorbers and one previously-known system. While two of these show both a broad, shallow component and a narrow, deep component (see Fig. 1), one of the new detections has only a single broad, shallow component. Interestingly, the host galaxies of the first two detections are classified as gas-rich spirals, while the latter is an early-type galaxy. These detections were obtained using a spectral-line finding method, based on Bayesian inference, developed for future large-scale absorption surveys (Allison et al. 2012a).Comment: 1 page, 1 figure, published in Proceedings of IAU Symposium No. 29

    Addressing learner diversity by promoting flexibility in e-learning environments

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    E-learning has opened a multitude of possibilities for teaching and learning. As the market matures there is a demand for more effective and cost-efficient learning interventions that meet the learning needs of the diverse learner population. Currently, however, very few teaching attempts have been made to match the pedagogical styles underlying e-learning interventions to students' diverse learning styles. Information and communication technologies can provide a variety of ways for adapting learning environments to students learning styles, although they are not often used to their full potential. In the Global Campus (GC) project at Middlesex University, we studied the differences in the learning styles of our distance and classroom students. We then examined the electronic learning resources and underlying pedagogical approach to establish how effectively they accommodate the diverse learning styles of the students. Finally, we proposed some measures to improve the e-learning environment in a way that matches the students' learning styles more effectively

    Perceptual Reports in (Dialects of) Arabic

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    This paper offers what is to our knowledge the ?rst description and analy-sis of the encoding of perceptual reports in Arabic: we focus here on ModernStandard Arabic (MSA) and Maltese (MT) building on the analytic frame-work offered by Asudeh and Toivonen (2012) (henceforth AT). We show thata range of different syntactic constructions are used to encode perceptual re-ports with seem-class redicates while the core semantic observation devel-oped in AT, concerning the distinction between types of PSOURCE, is foundto hold robustly in these languages. In the light of the data we outline, an im-portant question for future work turns out to be that of distinguishing casesof (genuine) copy-raising from constructions with thematic subjects (for theverbs in question). While Maltese is ideologically and sociolinguistically aseparate language, it shares many key aspects of its syntax with the Westernvernaculars of Arabic, and is fruitfully considered as a dialect of Arabic forthe purposes of cross-dialectal compariso

    Coherence-enhanced imaging of a degenerate Bose gas

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    We present coherence-enhanced imaging, an in situ technique that uses Raman superradiance to probe the spatial coherence properties of an ultracold gas. Applying this method, we obtain a spatially resolved measurement of the condensate number and more generally, of the first-order spatial correlation function in a gas of 87^{87}Rb atoms. We observe the enhanced decay of propagating spin gratings in high density regions of a Bose condensate, a decay we ascribe to collective, non-linear atom-atom scattering. Further, we directly observe spatial inhomogeneities that arise generally in the course of extended sample superradiance.Comment: 4 pages, 4 figure
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