Low bit-rate speech encoding for digital mobile radio

The need for low bit-rate speech coding is the result of growing demand on the available radio bandwidth for mobile communications both for military purposes and for the public sector. To meet this growing demand it is required that the available bandwidth be utilized in the most economic way to accommodate more services. Two low bit-rate speech coders have been built and tested in this project. The two coders combine predictive coding with delta modulation, a property which enables them to achieve simultaneously the low bit-rate and good speech quality requirements. To enhance their efficiency, the predictor coefficients and the quantizer step size are updated periodically in each coder. This enables the coders to keep up with changes in the characteristics of the speech signal with time and with changes in the dynamic range of the speech waveform. However, the two coders differ in the method of updating their predictor coefficients. One updates the coefficients once every one hundred sampling periods and extracts the coefficients from input speech samples. This is known in this project as the Forward Adaptive Coder. Since the coefficients are extracted from input speech samples, these must be transmitted to the receiver to reconstruct the transmitted speech sample, thus adding to the transmission bit rate. The other updates its coefficients every sampling period, based on information of output data. This coder is known as the Backward Adaptive Coder. Results of subjective tests showed both coders to be reasonably robust to quantization noise. Both were graded quite good, with the Forward Adaptive performing slightly better, but with a slightly higher transmission bit rate for the same speech quality, than its Backward counterpart. The coders yielded acceptable speech quality of 9.6kbps for the Forward Adaptive and 8kbps for the Backward Adaptive.

Assessment of time frequency warping for use as a reference degradation for assessing synthetic speech

At present there is no standard assessment method for rating and comparing the quality of synthesized speech. This study assesses the suitability of Time Frequency Warping (TFW) modulation for use as a reference device for assessing synthesized speech. Time Frequency Warping modulation introduces timing errors into natural speech that produce perceptual errors similar to those found in synthetic speech. It is proposed that TFW modulation used in conjunction with a listening effort test would provide a standard assessment method for rating the quality of synthesized speech. This study identifies the most suitable TFW modulation variable parameter to be used for assessing synthetic speech and assess the results of several assessment tests that rate examples of synthesized speech in terms of the TFW variable parameter and listening effort. The study also attempts to identify the attributes of speech that differentiate synthetic, TFW modulated and natural speech.

Nonlinear speech analysis algorithms mapped to a standard metric achieve clinically useful quantification of average Parkinson's disease symptom severity

The standard reference clinical score quantifying average Parkinson's disease (PD) symptom severity is the Unified Parkinson's Disease Rating Scale (UPDRS). At present, UPDRS is determined by the subjective clinical evaluation of the patient's ability to adequately cope with a range of tasks. In this study, we extend recent findings that UPDRS can be objectively assessed to clinically useful accuracy using simple, self-administered speech tests, without requiring the patient's physical presence in the clinic. We apply a wide range of known speech signal processing algorithms to a large database (approx. 6000 recordings from 42 PD patients, recruited to a six-month, multi-centre trial) and propose a number of novel, nonlinear signal processing algorithms which reveal pathological characteristics in PD more accurately than existing approaches. Robust feature selection algorithms select the optimal subset of these algorithms, which is fed into non-parametric regression and classification algorithms, mapping the signal processing algorithm outputs to UPDRS. We demonstrate rapid, accurate replication of the UPDRS assessment with clinically useful accuracy (about 2 UPDRS points difference from the clinicians' estimates, p < 0.001). This study supports the viability of frequent, remote, cost-effective, objective, accurate UPDRS telemonitoring based on self-administered speech tests. This technology could facilitate large-scale clinical trials into novel PD treatments.

An investigation into the comparable effectiveness of two tests of writing administered to college-level English as a Second Language students: The Computerized Placement Test and holistically scored essay exams

This dissertation describes the findings and implications of a correlational analysis. Scores earned on the Computerized Placement Test (CPT), sentence skills, were compared to essay scores of advanced English as a Second Language (ESL) students. As the CPT is designed for native speakers of English, it was hypothesized that it could be an invalid or unreliable instrument for non-native speakers. Florida community college students are mandated to take the CPT to determine preparedness, as are students at many other U.S. and Canadian colleges. If incoming students score low on the CPT, they may be required to take up to three semesters of remedial coursework. It is essential that scores earned by non-native speakers of English accurately reflect their ability level. They constitute a large and growing body of non-traditional students enrolled at community colleges.^ The study was conducted at Miami-Dade Community College, Wolfson Campus, fall 1997. Participants included 106 advanced ESL students who took both the CPT sentence skills test and wrote final essay exams. The essay exams were holistically scored by trained readers. Also, the participants took the Placement Articulation Software Service (PASS) exam, an alternative form of the CPT. Scores on the CPT and essays were compared by means of a Pearson product-moment correlation to validate the CPT. Scores on the CPT and the PASS exam were compared in the same manner to verify reliability. A percentage of appropriate placements was determined by comparing essay scores to CPT cutoff score ranges. Finally, the instruments were evaluated by means of independent-samples t-tests for performance differences between gender, age, and first language groups.^ The results indicate that the CPT sentence skills test is a valid and reliable placement instrument for advanced- level ESL students who intend to pursue community college degrees. The correlations demonstrated a substantial relationship between CPT and essay scores and a marked relationship between CPT and PASS scores. Appropriate placements were made in 86% of the cases. Furthermore, the CPT was found to discriminate equally among the gender, age, and first language groups included in this study. ^

The effectiveness of explicit individualized phonemic awareness instruction by a speech -language pathologist to preschool children with phonological speech disorders

This study investigated the effects of an explicit individualized phonemic awareness intervention administered by a speech-language pathologist to 4 prekindergarten children with phonological speech sound disorders. Research has demonstrated that children with moderate-severe expressive phonological disorders are at-risk for poor literacy development because they often concurrently exhibit weaknesses in the development of phonological awareness skills (Rvachew, Ohberg, Grawburg, & Heyding, 2003).^ The research design chosen for this study was a single subject multiple probe design across subjects. After stable baseline measures, the participants received explicit instruction in each of the three phases separately and sequentially. Dependent measures included same-day tests for Phase I (Phoneme Identity), Phase II (Phoneme Blending), and Phase III (Phoneme Segmentation), and generalization and maintenance tests for all three phases.^ All 4 participants made substantial progress in all three phases. These skills were maintained during weekly and biweekly maintenance measures. Generalization measures indicated that the participants demonstrated some increases in their mean total number of correct responses in Phase II and Phase III baseline while the participants were in Phase I intervention, and more substantial increases in Phase III baseline while the participants were in Phase II intervention. Increased generalization from Phases II to III could likely be explained due to the response similarities in those two skills (Cooper, Heron, & Heward, 2007).^ Based upon the findings of this study, speech-language pathologists should evaluate phonological awareness in the children in their caseloads prior to kindergarten entry, and should allocate time during speech therapy to enhance phonological awareness and letter knowledge to support the development of both skills concurrently. Also, classroom teachers should collaborate with speech-language pathologists to identify at-risk students in their classrooms and successfully implement evidence-based phonemic awareness instruction. Future research should repeat this study including larger groups of children, children with combined speech and language delays, children of different ages, and ESOL students.^

The Effectiveness of Explicit Individualized Phonemic Awareness Instruction By a Speech-Language Pathologist to Preschool Children With Phonological Speech Disorders

This study investigated the effects of an explicit individualized phonemic awareness intervention administered by a speech-language pathologist to 4 prekindergarten children with phonological speech sound disorders. Research has demonstrated that children with moderate-severe expressive phonological disorders are at-risk for poor literacy development because they often concurrently exhibit weaknesses in the development of phonological awareness skills (Rvachew, Ohberg, Grawburg, & Heyding, 2003). The research design chosen for this study was a single subject multiple probe design across subjects. After stable baseline measures, the participants received explicit instruction in each of the three phases separately and sequentially. Dependent measures included same-day tests for Phase I (Phoneme Identity), Phase II (Phoneme Blending), and Phase III (Phoneme Segmentation), and generalization and maintenance tests for all three phases. All 4 participants made substantial progress in all three phases. These skills were maintained during weekly and biweekly maintenance measures. Generalization measures indicated that the participants demonstrated some increases in their mean total number of correct responses in Phase II and Phase III baseline while the participants were in Phase I intervention, and more substantial increases in Phase III baseline while the participants were in Phase II intervention. Increased generalization from Phases II to III could likely be explained due to the response similarities in those two skills (Cooper, Heron, & Heward, 2007). Based upon the findings of this study, speech-language pathologists should evaluate phonological awareness in the children in their caseloads prior to kindergarten entry, and should allocate time during speech therapy to enhance phonological awareness and letter knowledge to support the development of both skills concurrently. Also, classroom teachers should collaborate with speech-language pathologists to identify at-risk students in their classrooms and successfully implement evidence-based phonemic awareness instruction. Future research should repeat this study including larger groups of children, children with combined speech and language delays, children of different ages, and ESOL students

Étude de la fidélité des paramètres de la raideur passive de l'articulation de la hanche et analyse de leurs relations avec les mesures cliniques

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Étude de la fidélité des paramètres de la raideur passive de l'articulation de la hanche et analyse de leurs relations avec les mesures cliniques

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Annotation Pro. Enhancing analyses of linguistic and paralinguistic features in speech

Annotation Pro - a description of techniques, methods implemented in the tool, as well as the list of all built in functionalities and features of the user interface, and usage tips.