650,861 research outputs found

    Non-photorealistic image rendering with a labyrinthine tiling

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    The paper describes a new image processing for a non-photorealistic rendering. The algorithm is based on a random generation of gray tones and competing statistical requirements. The gray tone value of each pixel in the starting image is replaced selecting among randomly generated tone values, according to the statistics of nearest-neighbor and next-nearest-neighbor pixels. Two competing conditions for replacing the tone values - one position on the local mean value the other on the local variance - produce a peculiar pattern on the image. This pattern has a labyrinthine tiling aspect. For certain subjects, the pattern enhances the look of the image.Comment: 9 pages, 5 figure

    Lexical tone awareness in Chinese children with developmental dyslexia

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    This study examined the extent and nature of lexical tone deficit in Chinese developmental dyslexia. Twenty Cantonese-speaking Chinese dyslexic children (mean age 8;11) were compared to twenty average readers of the same age (CA control group, mean age 8;11), and another twenty younger average readers of the same word reading level (RL control group, mean age 7;4) on different measures of lexical tone awareness, rhyme awareness and visual-verbal paired-associate learning. Results showed that the Chinese dyslexic children performed significantly worse than the CA but not the RL control groups in nearly all the lexical tone and rhyme awareness measures. Analyses of individual performance demonstrated that over one-third of the dyslexic children showed a deficit in some aspects of tone awareness. Tone discrimination and tone production were found to correlate significantly with Chinese word reading. These findings confirm that Chinese dyslexic children show weaknesses in tone awareness.published_or_final_versio

    Effect of inflow control on inlet noise of a cut-on fan

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    The control of turbulence and other inflow disturbances in anechoic chambers for static turbofan noise studies was studied. A cut-on, high tip speed fan stage was acoustically tested with three configurations of an inflow control device in an anechoic chamber. Although this was a cut-on design, rotor inflow interaction appeared to be a much stronger source of blade passing tone radiated from the inlet than rotor stator interaction for the 1.6 mean rotor chord separation. Aft external suction applied to the area where the inflow control device joined the inlet produced a further reduction in blade passing tone, suggesting that disturbances in the forward flow on the outside of the inlet were superimposed on the inlet boundary layer and were a significant source of tone noise

    Eigenvalue Estimates for submanifolds of N×RN \times \mathbb{R} with locally bounded mean curvature

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    We give lower bounds for the fundamental tone of open sets in submanifolds with locally bounded mean curvature in N×R N \times \mathbb{R}, where NN is an nn-dimensional complete Riemannian manifold with radial sectional curvature KNκK_{N} \leq \kappa. When the immersion is minimal our estimates are sharp. We also show that cylindrically bounded minimal surfaces has positive fundamental tone.Comment: 9 page

    Human summating potential using continuous loop averaging deconvolution: Response amplitudes vary with tone burst repetition rate and duration

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    Electrocochleography (ECochG) to high repetition rate tone bursts may have advantages over ECochG to clicks with standard slow rates. Tone burst stimuli presented at a high repetition rate may enhance summating potential (SP) measurements by reducing neural contributions resulting from neural adaptation to high stimulus repetition rates. To allow for the analysis of the complex ECochG responses to high rates, we deconvolved responses using the Continuous Loop Averaging Deconvolution (CLAD) technique. We examined the effect of high stimulus repetition rate and stimulus duration on SP amplitude measurements made with extratympanic ECochG to tone bursts in 20 adult females with normal hearing. We used 500 and 2,000 Hz tone bursts of various stimulus durations (12, 6, 3 ms) and repetition rates (five rates ranging from 7.1 to 234.38/s). A within-subject repeated measures (rate x duration) analysis of variance was conducted. We found that, for both 500 and 2,000 Hz stimuli, the mean deconvolved SP amplitudes were larger at faster repetition rates (58.59 and 97.66/s) compared to slower repetition rates (7.1 and 19.53/s), and larger at shorter stimulus duration compared longer stimulus duration. Our concluding hypothesis is that large SP amplitude to short duration stimuli may originate primarily from neural excitation, and large SP amplitudes to long duration, fast repetition rate stimuli may originate from hair cell responses. While the hair cell or neural origins of the SP to various stimulus parameters remains to be validated, our results nevertheless provide normative data as a step toward applying the CLAD technique to understanding diseased ears

    Convergent input from brainstem coincidence detectors onto delay-sensitive neurons in the inferior colliculus.

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    Responses of low-frequency neurons in the inferior colliculus (IC) of anesthetized guinea pigs were studied with binaural beats to assess their mean best interaural phase (BP) to a range of stimulating frequencies. Phase plots (stimulating frequency vs BP) were produced, from which measures of characteristic delay (CD) and characteristic phase (CP) for each neuron were obtained. The CD provides an estimate of the difference in travel time from each ear to coincidence-detector neurons in the brainstem. The CP indicates the mechanism underpinning the coincidence detector responses. A linear phase plot indicates a single, constant delay between the coincidencedetector inputs from the two ears. In more than half (54 of 90) of the neurons, the phase plot was not linear. We hypothesized that neurons with nonlinear phase plots received convergent input from brainstem coincidence detectors with different CDs. Presentation of a second tone with a fixed, unfavorable delay suppressed the response of one input, linearizing the phase plot and revealing other inputs to be relatively simple coincidence detectors. For some neurons with highly complex phase plots, the suppressor tone altered BP values, but did not resolve the nature of the inputs. For neurons with linear phase plots, the suppressor tone either completely abolished their responses or reduced their discharge rate with no change in BP. By selectively suppressing inputs with a second tone, we are able to reveal the nature of underlying binaural inputs to IC neurons, confirming the hypothesis that the complex phase plots of many IC neurons are a result of convergence from simple brainstem coincidence detectors

    Coherent Optical DFT-Spread OFDM

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    We consider application of the discrete Fourier transform-spread orthogonal frequency-division multiplexing (DFT-spread OFDM) technique to high-speed fiber optic communications. The DFT-spread OFDM is a form of single-carrier technique that possesses almost all advantages of the multicarrier OFDM technique (such as high spectral efficiency, flexible bandwidth allocation, low sampling rate and low-complexity equalization). In particular, we consider the optical DFT-spread OFDM system with polarization division multiplexing (PDM) that employs a tone-by-tone linear minimum mean square error (MMSE) equalizer. We show that such a system offers a much lower peak-to-average power ratio (PAPR) performance as well as better bit error rate (BER) performance compared with the optical OFDM system that employs amplitude clipping.Comment: This idea was originally submitted at Nov. 28th, 2009. After many times of rejection and resubmission, it was finally accepted by the journal of Advances in Optical Technologie

    Modulation of individual components of gastric motor response to duodenal glucose

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    AIM: To evaluate individual components of the antro-pyloro-duodenal (APD) motor response to graded small intestinal glucose infusions in healthy humans. METHODS: APD manometry was performed in 15 healthy subjects (12 male; 40 ± 5 years, body mass index 26.5 ± 1.6 kg/m2) during four 20-min intraduodenal infusions of glucose at 0, 0.5, 1.0 and 1.5 kcal/min, in a randomised double-blinded fashion. Glucose solutions were infused at a rate of 1 mL/min and separated by 40-min “wash-out” period. Data are mean ± SE. Inferential analyses are repeated measure analysis of variance with Bonferroni post-hoc testing. RESULTS: At 0 kcal/min frequency of pressure waves were: antrum (7.5 ± 1.8 waves/20 min) and isolated pyloric pressure waves (IPPWs) (8.0 ± 2.3 waves/20 min) with pyloric tone (0.0 ± 0.9 mmHg). Intraduodenal glucose infusion acutely increased IPPW frequency (P < 0.001) and pyloric tone (P = 0.015), and decreased antral wave frequency (P = 0.007) in a dose-dependent fashion. A threshold for stimulation was observed at 1.0 kcal/min for pyloric phasic pressure waves (P = 0.002) and 1.5 kcal/min for pyloric tone and antral contractility. CONCLUSION: There is hierarchy for the activation of gastrointestinal motor responses to duodenal glucose infusion. An increase in IPPWs is the first response observed.Adam M Deane, Laura K Besanko, Carly M Burgstad, Marianne J Chapman, Michael Horowitz, Robert JL Frase

    The Relationship Between the Perception and Production of Mandarin Tones: An Exploratory Study

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    This study looks at the relationship between the perception and production of Mandarin tones by non-native speakers studying Mandarin. This issue is first examined in terms of the relationship between the perception and production of speech, in general, and then in terms of Mandarin tone perception and Mandarin tone production. The subjects (N=33) were students studying Mandarin Chinese at the University of Hawai'i and were both native and non-native English speakers who neither spoke or heard Mandarin regularly outside of the classroom. Subjects were administered a three part "Mandarin Tone Test'' focusing on a) tone production, b) tone perception, and c) subject perception of their own tone production. 85% of the subjects perceived tones better than they produced the same tones. Further, subject perception errors appeared to be of two primary types: a) misidentification of a tone and b) identification of a tone according to incorrect tone features/boundaries. Overall, students showed global awareness of their tone production errors based upon subject tone "ratings". Finally, subject production, perception, and whole test mean scores increased corresponding to subject courselevel (100-, 200-, 400-)
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