317 research outputs found

    Sound effect synthesis

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    REAL-TIME PHYSICAL MODEL FOR SYNTHESIS OF SWORD SWING SOUNDS

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    Sword sounds are synthesised by physical models in real- time. A number of compact sound sources are used along the length of the sword which replicate the swoosh sound when swung through the air. Listening tests are carried out which reveal a model with reduced physics is perceived as more authentic. The model is further developed to be controlled by a Wii Controller and successfully extended to include sounds of a baseball bat and golf club

    Real-time physical model of an Aeolian harp

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    A real-time physical sound synthesis model of an Aeolian harp is presented. The model uses semi- empirical fluid dynamics equations to inform its operation, providing suitable parameters for users to interact. A basic wind model is included as well as an interface allowing user adjustable param- eters. Sounds generated by the model were subject to objective measurements against real-world recordings, which showed that many of the physical properties of the harp were replicated in our model, but a possible link between harmonics and vibration amplitude was not. A perceptual test was performed, where participants were asked to rate sounds in terms of how plausible they were in comparison with spectral modelling synthesis and recorded Aeolian Harp samples. Evaluation showed that our model performed as well as an alternative non-physical synthesis method, but was not as authentic as actual recorded samples

    Measurement of Stress Profiles by Phase Contrast Techniques

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    An acoustic wave pissing through a material has its velocity changed when stress is applied. This is due to changes in the third order elastic constant and the density of the material. By using a small diameter beam or a focused beam Incident on a metal and reflected from both its front and back surfaces, It is possible to measure the difference in phase of the two reflected waves; the beam Itself can be scanned over the surface of the material. Three kinds of measurements will be shown. The first relates the change of velocity of a compressional wave to the applied stress taken \u27in an MTS testing system. The second shows a scan of the profile of the velocity change around a circular defect. The third is an image of the stressed region around a circular defect obtained with a scanned electronically focused system operating in a phase contrast mode

    Learning to represent visual input

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    One of the central problems in computational neuroscience is to understand how the object-recognition pathway of the cortex learns a deep hierarchy of nonlinear feature detectors. Recent progress in machine learning shows that it is possible to learn deep hierarchies without requiring any labelled data. The feature detectors are learned one layer at a time and the goal of the learning procedure is to form a good generative model of images, not to predict the class of each image. The learning procedure only requires the pairwise correlations between the activations of neuron-like processing units in adjacent layers. The original version of the learning procedure is derived from a quadratic ‘energy’ function but it can be extended to allow third-order, multiplicative interactions in which neurons gate the pairwise interactions between other neurons. A technique for factoring the third-order interactions leads to a learning module that again has a simple learning rule based on pairwise correlations. This module looks remarkably like modules that have been proposed by both biologists trying to explain the responses of neurons and engineers trying to create systems that can recognize objects

    Real-time diagnostics of gas/water assisted injection moulding using integrated ultrasonic sensors

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    YesAn ultrasound sensor system has been applied to the mould of both the water and gas assisted injection moulding processes. The mould has a cavity wall mounted pressure sensor and instrumentation to monitor the injection moulding machine. Two ultrasound sensors are used to monitor the arrival of the fluid (gas or water) bubble tip through the detection of reflected ultrasound energy from the fluid polymer boundary and the fluid bubble tip velocity through the polymer melt is estimated. The polymer contact with the cavity wall is observed through the reflected ultrasound energy from that boundary. A theoretically based estimation of the residual wall thickness is made using the ultrasound reflection from the fluid (gas or water) polymer boundary whilst the samples are still inside the mould and a good correlation with a physical measurement is observed

    Cost evaluation of point-of-care testing for community-acquired influenza in adults presenting to the emergency department

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    Background Rapid molecular point-of-care tests (POCTs) for influenza have potential to produce cost savings in emergency departments (EDs) and acute care settings. To date, published projected savings have been based on estimated costs. Objectives This study aimed to describe the cost implications of a rapid influenza POCT using accurate real-world patient level costing data. 204 adult patients receiving point-of-care (POC) influenza testing in the ED as part of a routine clinical service were identified retrospectively, alongside a control cohort of 104 patients from the same influenza season. Costs for all were calculated at the individual patient level. Cost comparison was performed using an instrumental variable (IV) regression to overcome potential bias within the observational dataset. Results Patients who had a POCT on average cost 67 % less than those who did not (average cost reduction: £2066: 95 % CI: £624 and £2665). Moderate to high NEWS score at arrival, presence of ≥1 comorbidity, and age ≥70 years increased overall costs across both groups (p < 0.05). Conclusions Savings from POC testing can be attributed to more targeted treatments, fewer admissions and reduced lengths of stay. The IV regression results are supported by a second method (ordinary least square against baseline characteristics). They are also in line with existing work that use estimated costs but indicate greater savings than predicted previously. In conclusion, POC influenza testing in the emergency department produces significant cost savings, this is demonstrated here through an analysis using individual real-world patient level costing data
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