Matching Items (6)
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- All Subjects: Signal Processing
- All Subjects: swallowing
- All Subjects: observability
- All Subjects: Sensor networks--Mathematical models.
- Creators: Weinhold, Juliet
Description
Modern measurement schemes for linear dynamical systems are typically designed so that different sensors can be scheduled to be used at each time step. To determine which sensors to use, various metrics have been suggested. One possible such metric is the observability of the system. Observability is a binary condition determining whether a finite number of measurements suffice to recover the initial state. However to employ observability for sensor scheduling, the binary definition needs to be expanded so that one can measure how observable a system is with a particular measurement scheme, i.e. one needs a metric of observability. Most methods utilizing an observability metric are about sensor selection and not for sensor scheduling. In this dissertation we present a new approach to utilize the observability for sensor scheduling by employing the condition number of the observability matrix as the metric and using column subset selection to create an algorithm to choose which sensors to use at each time step. To this end we use a rank revealing QR factorization algorithm to select sensors. Several numerical experiments are used to demonstrate the performance of the proposed scheme.
ContributorsIlkturk, Utku (Author) / Gelb, Anne (Thesis advisor) / Platte, Rodrigo (Thesis advisor) / Cochran, Douglas (Committee member) / Renaut, Rosemary (Committee member) / Armbruster, Dieter (Committee member) / Arizona State University (Publisher)
Created2015
Description
The purpose of this study was to examine swallowing patterns using ultrasound technology subsequent to the implementation of two therapeutic interventions. Baseline swallow patterns were compared to swallows after implementation of therapeutic interventions common in both feeding therapy (FT) and orofacial myofunctional therapy (OMT). The interventions consist of stimulation of the tongue by z-vibe and tongue pops. Changes in swallowing patterns are described, and similarities of interventions across the two professions are discussed. Ultrasound research in the realm of swallowing is sparse despite having potential clinical application in both professions. In using ultrasound, this study outlines a protocol for utilization of a hand-held probe and reinforces a particular protocol described in the literature. Real-time ultrasound recordings of swallows for 19 adult female subjects were made. Participants with orofacial myofunctional disorder are compared to a group with typical swallowing and differences in swallowing patterns are described. Three stages of the oral phase of the swallow were assigned based on ultrasonic observation of the tongue shape. Analysis involves total duration of the swallow, duration of the three stages in relation to the total duration of the swallow, and the number of swallows required for the bolus to be cleared from the oral cavity. No significant effects of either intervention were found. Swallowing patterns showed a general trend to become faster in total duration subsequent to each intervention. An unexpected finding showed significant changes in the relationship between the bolus preparation stage and the bolus transportation stage when comparing the group classified as having a single swallow and the group classified as having multiple swallows.
ContributorsMckay, Michelle Diane (Author) / Weinhold, Juliet (Thesis director) / Scherer, Nancy (Committee member) / Department of Speech and Hearing Science (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Research on /r/ production previously used formant analysis as the primary acoustic analysis, with particular focus on the low third formant in the speech signal. Prior imaging of speech used X-Ray, MRI, and electromagnetic midsagittal articulometer systems. More recently, the signal processing technique of Mel-log spectral plots has been used to study /r/ production in children and female adults. Ultrasound imaging of the tongue also has been used to image the tongue during speech production in both clinical and research settings. The current study attempts to describe /r/ production in three different allophonic contexts; vocalic, prevocalic, and postvocalic positions. Ultrasound analysis, formant analysis, Mel-log spectral plots, and /r/ duration were measured for /r/ production in 29 adult speakers (10 male, 19 female). A possible relationship between these variables was also explored. Results showed that the amount of superior constriction in the postvocalic /r/ allophone was significantly lower than the other /r/ allophones. Formant two was significantly lower and the distance between formant two and three was significantly higher for the prevocalic /r/ allophone. Vocalic /r/ had the longest average duration, while prevocalic /r/ had the shortest duration. Signal processing results revealed candidate Mel-bin values for accurate /r/ production for each allophone of /r/. The results indicate that allophones of /r/ can be distinguished based the different analyses. However, relationships between these analyses are still unclear. Future research is needed in order to gather more data on /r/ acoustics and articulation in order to find possible relationships between the analyses for /r/ production.
ContributorsHirsch, Megan Elizabeth (Author) / Weinhold, Juliet (Thesis director) / Gardner, Joshua (Committee member) / Department of Speech and Hearing Science (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
The purpose of this study was to identify acoustic markers that correlate with accurate and inaccurate /r/ production in children ages 5-8 using signal processing. In addition, the researcher aimed to identify predictive acoustic markers that relate to changes in /r/ accuracy. A total of 35 children (23 accurate, 12 inaccurate, 8 longitudinal) were recorded. Computerized stimuli were presented on a PC laptop computer and the children were asked to do five tasks to elicit spontaneous and imitated /r/ production in all positions. Files were edited and analyzed using a filter bank approach centered at 40 frequencies based on the Mel-scale. T-tests were used to compare spectral energy of tokens between accurate and inaccurate groups and additional t-tests were used to compare duration of accurate and inaccurate files. Results included significant differences between the accurate and inaccurate productions of /r/, notable differences in the 24-26 mel bin range, and longer duration of inaccurate /r/ than accurate. Signal processing successfully identified acoustic features of accurate and inaccurate production of /r/ and candidate predictive markers that may be associated with acquisition of /r/.
ContributorsBecvar, Brittany Patricia (Author) / Azuma, Tamiko (Thesis advisor) / Weinhold, Juliet (Committee member) / Berisha, Visar (Committee member) / Arizona State University (Publisher)
Created2017
Description
The purpose of this longitudinal study was to predict /r/ acquisition using acoustic signal processing. 19 children, aged 5-7 with inaccurate /r/, were followed until they turned 8 or acquired /r/, whichever came first. Acoustic and descriptive data from 14 participants were analyzed. The remaining 5 children continued to be followed. The study analyzed differences in spectral energy at the baseline acoustic signals of participants who eventually acquired /r/ compared to that of those who did not acquire /r/. Results indicated significant differences between groups in the baseline signals for vocalic and postvocalic /r/, suggesting that the acquisition of certain allophones may be predictable. Participants’ articulatory changes made during the progression of acquisition were also analyzed spectrally. A retrospective analysis described the pattern in which /r/ allophones were acquired, proposing that vocalic /r/ and the postvocalic variant of consonantal /r/ may be acquired prior to prevocalic /r/, and /r/ followed by low vowels may be acquired before /r/ followed by high vowels, although individual variations exist.
ContributorsConger, Sarah Grace (Author) / Weinhold, Juliet (Thesis director) / Daliri, Ayoub (Committee member) / Bruce, Laurel (Committee member) / College of Health Solutions (Contributor, Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
The purpose of this study was to explore the relationship between acoustic indicators in speech and the presence of orofacial myofunctional disorder (OMD). This study analyzed the first and second formant frequencies (F1 and F2) of the four corner vowels [/i/, /u/, /æ/ and /ɑ/] found in the spontaneous speech of thirty participants. It was predicted that speakers with orofacial myofunctional disorder would have a raised F1 and F2 because of habitual low and anterior tongue positioning. This study concluded no significant statistical differences in the formant frequencies. Further inspection of the total vowel space area of the OMD speakers suggested that OMD speakers had a smaller, more centralized vowel space. We concluded that more study of the total vowel space area for OMD speakers is warranted.
ContributorsWasson, Sarah Alicia (Co-author) / Wasson, Sarah (Co-author) / Weinhold, Juliet (Thesis director) / Daliri, Ayoub (Committee member) / College of Health Solutions (Contributor) / Hugh Downs School of Human Communication (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05