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Title: Perceptual centers in speech-acoustic determinants
Author: Scott, Sophie Kerttu.
ISNI:       0000 0001 3390 7715
Awarding Body: University College London (University of London)
Current Institution: University College London (University of London)
Date of Award: 1993
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Perceptual centres, or P-centres, represent the perceptual moments of occurrence of acoustic signals - the 'beat' of a sound. P-centres underlie the perception and production of rhythm in perceptually regular speech sequences. P-centres have been model ed both in speech and non speech (music) domains. The three aims of this thesis were tost out current P-centre models to determine which best accounted for the experimental data b)to identify a candidate parameter to map P-centres onto (a local approach) as opposed to the previous global models which rely upon the whole signal to determine the P-centrethe final aim was to develop a model of P-centre location which could be applied to speech and non speech signals. The first aim was investigated by a series of experiments in whicha)speech from different speakers was nvestigated to determine whether different models could account for variation between speakersb)whether rendenng the amplitude time plot of a speech signal affects the P-centre of the signa whether increasing the amplitude at the offset of a speech signal alters P-centres in the production and perception of speech. The second aim was carried out by manipulating the rise time of different speech signals to determine whether the P-centre was affected, and whether the type of speech sound ramped affected the P-centre shift1 manipulating the rise time and decay time of a synthetic vowel to determine whether the onset alteration was had more affect on P-centre than the offset manipulationnd whether the duration of a vowel affected the P-centre, if other attributes (amplitude, spectral contents) were held constant. The third aim - modelling P-centres - was based on these results. The Frequency dependent Amplitude Increase Model of P-centre location (FAIM) was developed using a modelling protocol, the APU GammaTone Flterbank and the speech from different speakers. The P-centres of the stimuli corpus were highly predicted by attributes of the increase in amplitude within one output channel of the filterbank. When this was used to make predictions of the P-centres for all the stimuli used in the thesis, 85°c of the observed variance was accounted for. The FAIM approach combines aspects of previous speech and non speech models (Gordon 1987, Marcus 1981, Vos and Rasch 1981). P-centre were thus modelled n a non speech specific, local manner.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Perceptual centres; P-centres