38,144 research outputs found

    Modelling and directionally encoding the acoustics of a room

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    Geometrical methods are often used to model the acoustic properties of a room, but are valid only for high frequencies. At low frequencies. diffraction and the effects of room modes cannot be neglected. A method for modelling the two-dimensional propagation of sound within an enclosed room is presented which encompasses both of these particular properties by making use of a digital waveguide model

    Waveguide physical modeling of vocal tract acoustics: flexible formant bandwidth control from increased model dimensionality

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    Digital waveguide physical modeling is often used as an efficient representation of acoustical resonators such as the human vocal tract. Building on the basic one-dimensional (1-D) Kelly-Lochbaum tract model, various speech synthesis techniques demonstrate improvements to the wave scattering mechanisms in order to better approximate wave propagation in the complex vocal system. Some of these techniques are discussed in this paper, with particular reference to an alternative approach in the form of a two-dimensional waveguide mesh model. Emphasis is placed on its ability to produce vowel spectra similar to that which would be present in natural speech, and how it improves upon the 1-D model. Tract area function is accommodated as model width, rather than translated into acoustic impedance, and as such offers extra control as an additional bounding limit to the model. Results show that the two-dimensional (2-D) model introduces approximately linear control over formant bandwidths leading to attainable realistic values across a range of vowels. Similarly, the 2-D model allows for application of theoretical reflection values within the tract, which when applied to the 1-D model result in small formant bandwidths, and, hence, unnatural sounding synthesized vowels

    Measuring brand image: Shopping centre case studies

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    'Branding' is well known for consumer products but power has shifted from manufacturers' brands towards retailers'. The term 'image' is more common than 'brand' in the context of shopping centres, but 'branding' may become more important. In this study, the authors first investigated qualitatively, asking shoppers to describe centres in 'personality' terms and eliciting clear descriptive differences between centres. For example, one in-town centre was 'dull, boring and old-fashioned . . . not exciting, just OK'; a larger regional centre was 'trendy, prestigious . . . strong, vibrant, big and colourful'. Second, the authors evaluated six UK shopping centres quantitatively using a questionnaire survey (n = 287). The 'strong and vibrant' centre scored significantly higher than the 'dull and boring' one. Despite 'branding' being little used by shopping centres, those with the better 'brand images' tended to have larger catchment areas, sales and rental incomes. The authors contend that brand management could pay rewards in terms of customer numbers, sales turnover and rental income

    Pathways for Nutrient Loss to Water; Slurry and Fertilizer Spreading

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    End of project reportThere are almost 150,000 farms in Ireland and these contribute substantial quantities of N and P to inland and coastal waters. Some of these nutrients are carried from wet soils by overland flow and by leaching from dry soils. Farm practice can reduce the loss from farms by judicious management of nutrients. Improvements are required to diminish export of nutrients without impairing operations on the farm. Literature regarding nutrient loss from agriculture was reviewed in this project and maps were prepared to predict best slurry spreading times around Ireland. Two further maps were prepared to show slurry storage requirement on farms
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