O objetivo é caracterizar a voz e vibração glótica de pregas vocais com paralisia unilateral. Método: trata-se de um estudo retrospectivo que utilizou o banco de dados do grupo de pesquisa em engenharia médica da Universidade Federal de São Carlos. Foram utilizados dados de 35 pacientes adultos (11 homens e 24 mulheres) e cinco instrumentos de análise multidimensional. O primeiro deles foi o protocolo de auto-avaliação (Índice de Desvantagem Vocal - IDV). Foram extraídos os escores de domínio: físico, orgânico, emocional e total. Foram utilizados sinais de voz para realizar as análises: perceptivo-auditiva (escala analógica visual - EVA e parâmetros: grau global - G, rugosidade - R, soprosidade - S, tensão - T e Instabilidade na emissão vocal - I); acústica tradicional (parâmetros de perturbação - Jitter e Shimmer), experimental (parâmetro Coaptação Glótica - CG) e a análise não linear (NL) da dinâmica vocal (parâmetros qualitativos: número de loops, graus de convergência e regularidade; e quantitativos: desvio padrão do eixo e da dispersão - DPE, DPD). A quinta análise utilizou quimografias geradas de videolaringoscopias em alta velocidade para extração de parâmetros quantitativos (Razão de Abertura - RA, de Fechamento - RF e Assimetria). Análise estatística: descritiva e correlação de Spearman. Resultados: A análise perceptiva caracterizou intensidade moderada do desvio vocal. A rugosidade foi o tipo de voz predominante em amostras masculinas (55,84%) e a soprosidade em amostras femininas (63,59%). Os domínios de IDV apresentaram baixo impacto da disfonia na qualidade de vida dos pacientes. Houve correlação do domínio físico com S em amostras masculinas e com todos os parâmetros perceptivos em amostras femininas. Ambas as amostras apresentaram parâmetros de perturbação aumentados (Jitter: 0,90% homens e 1,20% mulheres; Shimmer: 3,30% homens e 2,76% mulheres), e de CG diminuídos (0,28 homens e 0,25 mulheres). Amostras femininas apresentaram correlação de Jitter e Shimmer com os parâmetros perceptivos. Amostras masculinas apresentaram correlação de Jitter com R e de Shimmer com R e T. A CG correlacionou com a S e l em amostras masculinas. Na análise NL da dinâmica vocal de ambas as amostras apresentaram reduzidos: número de loops, grau de convergência e de regularidade, enquanto que os valores de DPE e DPD apresentaram-se aumentados. Houve correlação de parâmetros perceptuais com os da análise NL em ambas as amostras. Os resultados de parâmetros quimográficos são: RA 1,55 para homens e 1,50 para mulheres; RF 0,37 para homens e 0,18 para mulheres; e Assimetria: 23,68º para homens e 9, 85º para mulheres. Todos os parâmetros perceptuais femininos correlacionaram com os quimográficos, exceto a I. A I de amostras masculinas correlacionou com RF. Conclusão: a caracterização vocal de pacientes com paralisia unilateral de pregas vocais foi possível usando a avaliação multidimensional da voz. / The goal is to characterize the voice and glottal vibration of patients with unilateral vocal fold paralysis. Method: this is a retrospective study that used database samples of Universidade de São Carlos\'s research group in medical engineering. Data from 35 adults patients (11 men and 24 women) and five were used. They were used five tools for multidimensional analysis. The first one was the self-assessment protocol (Voice Handicap Index - VHI). Physical, organic, emotional and total scores were extracted. Voice signals were used in analyzes: perceptual (visual analogue scale - VAS and parameters: overall degrees - G, roughness - R, Breathiness - B, tension - T and instability in phonation - I); traditional acoustic (perturbation parameters - Jitter and Shimmer), experimental (glottal cloure parameter - GC) and nonlinear (NL) dynamic vocal analysis (Qualitative: number of loops, regularity and convergence degree. Quantitative: standard deviation of dispersion - SDD and standard deviation of the axis - SDA). The fifth analysis it was performed through extraction of kymographic parameters generated of the High speed videolaryngoscopys (Opening reason - Or; Closed reason - Cr and Asymmetry). Statistical analysis: descriptive and Spearman correlation. Results: perceptual analysis characterized moderate intensity of vocal deviation. Roughness was the predominant kind of voice in males samples (55,84%) and Breathiness in females samples (63,59%). VHI\'s scores showed low impact of dysphonia in the patients\' quality of life. There was correlation between score physical and B in the male samples and between score physical and all perceptual parameters in the female samples. Both samples showed increased of perturbation parameters (Jitter: 0.90% men and 1.20% women and Shimmer: 3.30% men and 2.76% women) and GC decreased (0.28 men and women 0.25). Female samples showed correlation of Jitter and Shimmer with all perceptual parameters. Male samples showed correlation of Jitter with the R and Shimmer with R and T. GC correlation with B and I only male samples. Qualitative NL dynamic vocal analysis showed number of loops, regularity and convergence degree reduced, whereas quantitative analysis of SDD and SDA increased. There were correlations between perceptual parameters and of nonlinear dynamic vocal analysis for both the samples. Results of Kymographic parameters are Or: 1.55 for men and 1.50 for women; Cr: 0.37 for men and 0.18 for women; and Asymmetry: 23.68º for men and 9.85º for women. All perceptual parameters correlate with Or and Cr at female samples, except I. Male samples showed correlation between I and Cr. Conclusion: the vocal characterization of patients with unilateral vocal fold paralysis was possible using the multidimensional voice assessment.

Diversos estudos foram realizados para detecção de patologias na laringe. Essas patologias causam alteração na frequência, amplitude e formato de onda do sinal de voz e podem ser estudadas através dos parâmetros convencionais de análise como jitter e shimmer, ou sob o enfoque da dinâmica não linear. Essas técnicas são não invasivas e servem de apoio ao especialista da área de fonoaudiologia para o diagnóstico de patologias nas pregas vocais. As técnicas de análise acústica baseiam-se no formato de onda vocal no domínio do tempo e domínio da frequência, enquanto que a técnica de análise não linear utilizada nesse trabalho baseia-se no atrator reconstruído do sinal de voz. O objetivo dessa tese é diferenciar vozes normais e patológicas e entre patologias usando a técnica de análise não linear conhecida como Seção de Poincaré. Foram analisados 48 sinais de vozes humanas, divididos em 3 grupos (16 normais, 16 com nódulo e 16 com edema de Reinke). Em seguida foram selecionados 3 trechos de 500 ms nos intervalos 0.5s-1.0s, 2.0s-2.5s e 4.0s-4.5s chamado de primeiro critério e um trecho 500ms no trecho de maior variação de pitch, chamado de segundo critério. Em seguida, o atrator foi reconstruído em 3 dimensões, determinado o atrator médio, e de cada ponto do atrator médio foi extraída a seção de Poincaré. De cada seção de Poincaré foi calculada a dispersão dos pontos do atrator no plano através da média e desvio padrão das dispersão dos pontos da seção de Poincaré em relação ao ponto médio da seção. A validação da ferramenta desenvolvida para essa tese foi realizada utilizando um sinal senoidal inserindo jitter gradativamente, onde verificou-se uma variação proporcional da média da dispersão. Os resultados obtidos mostraram que não foi possível diferenciar patologias mas foi possível classificar vozes normais das patológicas. O melhor intervalo para classificar as vozes normais das patológicas utilizando o primeiro critério foi entre 0.5s-1.0s pois nesse intervalo todas as vozes normais foram classificadas corretamente. No entanto, 6 vozes patológicas foram classificadas como normais com 2 vozes patológicas na fronteira que separa as vozes normais das patológicas. O segundo critério classificou todas as vozes normais corretamente e apenas uma voz patológica foi classificada como patológica. Concluiu-se que a ferramenta proposta utilizando o segundo critério mostrou-se superior em relação ao primeiro critério para diferenciar vozes normais das patológicas. / Several studies have been performed to detect pathologies of the larynx. These pathologies cause changes in the frequency, amplitude, and waveform of the voice signal. They can be studied by means of conventional analysis parameters such as jitter and shimmer, or from nonlinear dynamics concepts. These techniques are noninvasive and can help the speech therapist to better diagnose the pathologies in the vocal folds. The acoustic analysis techniques are based on the voice waveform in the time and frequency domains, while the non-linear analysis techniques are based on the attractor reconstructed from the speech signal.The aim of this thesis is to differentiate normal and pathological voices using a nonlinear analysis technique named Poincaré section. We analyzed 48 human voice signals divided into 3 groups (16 normal, 16 nodule and 16 Reinke\'s edema). Then, we analyzed 3 stretches of 500ms in the intervals 0.5s-1.0s, 2.0s-2.5s e 4.0-4.5s, denominated first criteria, and a stretch of 500ms in a higher variation in pitch, denominated second criteria. The attractor was then reconstructed in three dimensions, the average attractor was determined, and at each point of the average attractor, a Poincaré section was extracted. From each Poincaré section, the dispersion of the points of the attractor was calculated in the plane by means of the statistical average and standard deviation related to the medium point of the section. The validation of the tool developed for this thesis was achieved by inserting jitter gradually in a sinusoidal wave, where there was a proportional variation of average\'s dispersion was observed. The results obtained for this set of voices showed that the average and standard deviation of dispersion of the points in the Poincaré section differentiate the groups of voices, but not the pathological groups. The Statistical tests of Anova and Tukey were used to analyze the 3 groups and all group pairings, two by two, with a statistical significance of 5%. The best interval to classify normal voices from pathological voices by means of the first criteria was between 0.5s-1.0s, given the fact that in this interval, all normal voices were correctly classified. However, 6 pathological voices were classified as normal voices, with 2 voices border lining the frontier between normal voices from pathological voices. The second criteria classified all normal voices correctly, with only one pathological voice incorrectly classified. In conclusion, the second criteria tool proposed by this thesis was proven superior to differentiate normal voices from pathological ones.

With the advent of power electronics, inverter-driven induction motor are finding increased use in industries because of applications that demand variable speed operations and because of the potential savings in energy usage. However, these drives sometimes produce unacceptably high levels in vibration and acoustic noise. A literature survey has revealed that while there has been intensive research on the design of inverters to minimize acoustic noise radiation from these drives, the vibro-acoustic behaviour of an induction motor structure has received relatively little attention. The primary objective of this research project, therefore, is to develop a general strategy/algorithm for estimating the acoustic noise radiated from inverter-driven induction motors. By using a three-phase, 2.2 kW induction motor, the vibration modes due to various structural components (such as the rotor, the stator/casing, the endshields and the base plate) of the motor structure were analysed by experimental modal testing. Results indicate that the vibration modes due to the rotor are only important at low frequencies. It has been found that the power injection method gives more accurate measurement of the damping of a motor structure than the modal testing and the time decay methods. If a point force excitation is used, then it is more accurate to measure the sound radiation efficiency than the power conversion efficiency for motor structures. The effect of three different inverter designs (an ideal ???almost sinusoidal??? controller and two commercially available PWM inverters) on the radiated acoustic power were assessed for both no-load and load conditions using sound intensity measurements conducted in an anechoic room. The results indicate that although the sound power level due to aerodynamic and mechanical noise increases at a rate of 12 dB per doubling of the motor speed, the electromagnetic noise dominates at low motor speeds and is still a significant noise source even at high motor speeds. For inverters with low switching frequencies, the radiated sound power level is almost 15 dB higher than the ideal case at low speeds and is relatively insensitive to the motor speed. For inverters that implement the random modulation technique, the change in the total sound power level with the level of the random modulation is very small but the tonal nature of the noise is greatly reduced. The vibration behaviour of a motor structure was modeled using the finite element method (FEM) and validated using the experimental modal testing results. It has been found that it is essential to model the laminated stator as an orthotropic structure. While the details of other structural components (such as the endshields, the teeth in the stator and the windings) are not so important, it is essential that they are incorporated into the structural model as simplified structures to account for their mass, stiffness and boundary conditions imposed on the motor structure. Based on this structural model, the radiated acoustic power for various operating conditions has been predicated using the boundary element (BEM) and the electromagnetic force calculated from an electromagnetic finite element model. The predicted results agree reasonably well with experimental measurements. Despite the success of the FEM/BEM approaches, they can be prohibitively expensive (in terms of computer resources required) to apply to large motors and high frequencies. Thus the feasibility of using a statistical method, namely, the statistical energy analysis (SEA), to estimate the radiated acoustic sound power from an inverter-driven induction motor has been examined. In order to carry out this analysis, analytical expressions for calculating the natural frequencies and radiation efficiency of finite length circular cylindrical shells (which are simplified models of the stator and casing of a motor structure) were firstly derived. The internal loss factors and coupling loss factors of the motor structure were determined experimentally using the power injection method. Then by introducing an equivalent surface mobility of circular cylindrical shells for the electromagnetic force, the vibration response and the acoustic noise radiated from each part of the motor structure were estimated. Results indicate that SEA method is potentially an efficient and effective tool in estimating the noise radiated from inverter-driven induction motors.

Diversi studi hanno dimostrato i reciproci rapporti di influenza tra respiro e variabili psicologiche ma scarsa attenzione è stata rivolta all’indagine delle funzioni espressive del suono del respiro. Studio 1 è stato finalizzato alla costruzione di un modello di analisi multi-livello per la descrizione acustica del respiro. Sono state effettuate audio e video registrazioni del respiro di 2 coppie di soggetti in performance individuali e congiunte. Sui 1903 respiri raccolti sono state condotte analisi video e audio che hanno portato alla costruzione di tre categorie di indici: respiratori, acustici e interattivi (relativi alla relazione tra i comportamenti respiratori di due partners in un’azione congiunta). Studio 2 ha investigato cosa poteva essere inferito dall’ascolto del suono respiro relativamente all’identità, allo stato emotivo e all’attività svolta da una persona. Inoltre, ha verificato se l’imitazione facilitasse l’identificazione rispetto al solo ascolto. Sono state raccolte registrazioni ecologiche del respiro di persone coinvolte in 6 attività e 4 emozioni. Un campione di 90 persone ha ascoltato le tracce e risposto ad un questionario relativo alle suddette variabili. Altre 90 persone prima di rispondere imitavano il respiro. Il campione ha efficacemente inferito informazioni relative alle variabili indagate, con risultati migliori nel task di imitazione. Studio 3 mirava a descrivere acusticamente 6 condizioni di respiro emotivo (rabbia, paura, tristezza, disgusto, tenerezza, gioia) e a investigare se “respirare insieme” influenzasse il processo di sintonizzazione. 20 coppie di donne hanno partecipato. Per ogni emozione, entro ogni coppia una partecipante leggeva una storia emotivamente connotata e respirava come se si trovasse in quella situazione. L’altra esprimeva la propria vicinanza respirando come lei. Al termine rispondevano a un questionario. I respiri sono stati audio registrati e analizzati. E’ stato possibile ricondurre ciascuna delle emozioni a un differente pattern respiratorio. Inoltre il task ha influenzato diverse dimensioni della sintonizzazione: la sincronizzazione, il decoding emotivo, l’esperienza emotiva e la percezione di somiglianza interpersonale. / Several psycho-physiological studies have provided evidences about the reciprocal influence between respiration and psychological variables but few attentions have been brought to the investigation of the expressive function of breathing sounds. Study 1 aims to build a multilayer analysis model that enable an acoustic description of breathing sounds. Audio and video recordings of breathing of two pairs of participants engaged in individual and joint performance were conducted. 1903 were video and audio analyzed and 3 sets of indexes were derived: respiratory, acoustic and interactive (aimed to relate partner’s respiratory behaviour during joint performances). Study 2 investigates what could be inferred about a person’s identity, emotional state and activity from the sound of his/her breathing. Moreover, it aims to verify whether imitation of breathing patterns improve the identification of those features. Ecological recordings of breathing sounds of people engaged in 6 activities and 4 emotions. 90 participants listen to the tracks and answer a questionnaire about such variables. Other 90 mimicked the tracks before answering. Participants were able to infer valuable information about the aspects under investigation with better results in the imitation task. Study 3 aims to describe the acoustic features of 6 emotional breathing patterns (anger, fear, sadness, disgust, tenderness and joy) and to see whether breathing together could strengthen the attunement process. 20 pairs of women participated. For each emotion, within the pair one participant read a story emotionally connoted and breathes as if she actually was in that situation. Her partner had to convey her closeness breathing in the same way. Finally they filled in a questionnaire. Different respiratory patterns were related to each emotion. Moreover the task influenced several attunement dimensions: synchronization, emotional decoding, emotional experience and perception of interpersonal similarity.

In Sweden over 10.000 patients annually, mostly children, undergo tonsillar surgery. The most common surgical method is total removal of the tonsil, tonsillectomy (TE). During the last decade partial tonsil resection, tonsillotomy (TT), has been reintroduced and is associated with lower primary morbidity and less postoperative pain. The aim of the present study was to evaluate if and to what extent 4-5 year old children’s voice function are affected by tonsillar hypertrophy compared to controls and to study the effects of the two surgical techniques on vocal function. Sixty-seven children with tonsillar hypertrophy, where randomized either to TE or TT. A voice material consisting of words with only sonorants and three sustained vowels was recorded preoperatively and six months postoperatively. Eighty-two preschool children formed two control groups. The material was evaluated perceptually by three voice specialized speech and language pathologist and analyzed acoustically. Before surgery the children with tonsillar hypertrophy are rated to have higher prevalence of hoarseness, hyponasality and ‘compressed/throaty voice’ compared with the controls. The acoustic analysis show that the children with tonsillar hypertrophy have higher prevalence of perturbation (jitter (%), shimmer (%) and NHR) compared to the controls. Postoperatively there are no significant difference between the children with tonsillar hypertrophy and the control group perceptually. The acoustic analysis of the children with tonsillar hypertrophy still show more perturbation compared to the control group. The children operated with TE are rated to have less prevalence of roughness and hyponasality after surgery. The children in the TT-group have less prevalence of roughness, hyponasality and ‘compressed/throaty voice’. The acoustic analysis show no significant difference between the two postoperative groups. / Över 10 000 patienter tonsillopereras årligen i Sverige, de flesta av dem barn. Den vanligaste kirurgiska metoden har sedan länge varit totalt avlägsnande av tonsillerna, tonsillektomi (TE). Under det senaste decenniet har partiellt borttagande av tonsillvävnad, tonsillotomi (TT) erövrat terräng då operationen är förknippad med lägre postoperativ morbiditet och lägre smärta. Syftet med föreliggande studie var att undersöka om och hur röstfunktionen är påverkad av tonsillhypertrofi hos barn i 4-5 års ålder i jämförelse med köns- och åldersmatchade kontroller samt att studera effekterna på röstfunktionen efter två olika typer av kirurgisk behandling, TE respektive TT. I föreliggande studie deltog 67 barn med tonsillhypertrofi som randomiserades till antingen TE eller TT. Ett röstmaterial bestående av ord som till största del bestod av sonoranter samt tre uthållna vokaler spelades in omedelbart före operation samt 6 månader postoperativt. Åttiotvå köns- och åldersmatchade förskolebarn utgjorde två kontrollgrupper. Materialet bedömdes perceptuellt av tre röstlogopeder samt analyserades akustiskt. Barnen med tonsillhypertrofi uppfattas före operation ha högre förekomst av de perceptuella parametrarna heshet, hyponasalitet, och klämd/halsig i jämförelse med köns- och åldersmatchade kontroller. Den akustiska analysen i sin tur visar på mer perturbation (jitter (%), shimmer (%) och NHR) hos barnen med tonsillhypertrofi. Efter kirurgisk behandling visar den perceptuella röstbedömningen att det inte föreligger någon signifikant skillnad mellan de barn som genomgått kirurgisk behandling och kontrollerna. Den akustiska analysen visar på att både barnen som genomgått TE och barnen som genomgått TT har mer perturbation i jämförelse med köns- och åldersmatchade kontroller. Vid jämförelse pre- och postoperativt visar röstbedömningen på en minskning av skrovlighet och hyponasalitet för barnen som genomgått TE samt skrovlighet, hyponasalitet och klämd/halsig för barnen som genomgått TT. Den akustiska analysen visar på att det inte föreligger någon större skillnad mellan barnen som genomgått TE och barnen som genomgått TT.

The efficacy of aural modeling in music education at the primary and secondary levels is well documented, and anecdotal evidence among university studio voice teachers abounds. However, this topic has not previously been explored with undergraduate level singers using acoustic analysis of the singing voice. This investigation utilized a survey on listening behaviors to examine undergraduate voice students’ use of recorded aural models. In addition, an empirical study measured the effect of repeated exposure to recorded aural models on participants’ vocal production. Research was conducted at Southwestern University, a private liberal arts institution in Georgetown, Texas. Study participants were divided into two groups. The control group performed a newly-composed melody after a recorded aural model of the melody was played a single time. The experimental group completed 10-minute listening assignments once a day for a five-day period before performing the same melody. Data between the non-listening and listening groups was compared. Using a second newly composed melody, the control group then completed a five-day listening assignment and performed the second melody. Pre- and post-listening data from this group of subjects was compared. Listening assignments were adapted from a speech pathology remediation technique known as auditory bombardment. They involved listening to multiple repetitions of the recorded aural model without attempting to practice singing the melody. The study measured four acoustic parameters: musical accuracy (pitch and rhythm), vowel/consonant articulation, use of vibrato, and ratio of power between overtones above and below 2 kHz. The listening behavior survey revealed that most students use recorded aural models in their practice time. However, results indicated that students would benefit from professional quality aural models and specific information about appropriate time parameters for listening activities. Results of the empirical study revealed a statistically significant 20-30% improvement in vocal production in both the experimental listening group and the control group post-listening. These data demonstrate that focused periods of listening to an aural model are effective in improving vocal production, even within a short period of time. The results of this study support the inclusion of aural modeling in the applied voice studio. / text

No description available.

Rörfonation och traditionell svensk röstbehandling är två av de vanligaste behandlingsalternativen inom svensk röstlogopedi idag. Som forskare är det viktigt att kontinuerligt utvärdera de behandlingar som erbjuds för att göra vården mer kvalitativ och kostnadseffektiv. Finns det skillnader i behandlingseffekt mellan dessa två röstbehandlingar? Är skillnaderna så tydliga att det går att fastslå att den ena behandlingen är att föredra framför den andra? Med analyser av ett patientmaterial, före och efter behandling, i form av akustisk analys, perceptuella bedömningar av en grupp erfarna logopeder samt patienternas självskattningar syftar föreliggande uppsats till att besvara vad behandlingsformerna har för effekt inom dessa områden. Patientmaterialet bestod av totalt 28 patienter varav 23 fullföljde behandling. Tolv av dessa erhöll behandling med rörfonation medan resterande elva patienter erhöll traditionell svensk röstbehandling.. Utöver röstinspelningar bestod materialet av patienternas självskattningar, i form av RHI- och Swe-VAPP-formulär. Gällande behandlingseffekt på akustiska parametrar kunde inga slutsatser dras. De perceptuella parametrarna afoni, hyperfunktion och knarr förbättrades sett till hela urvalet, oavsett typ av röstbehandling. Tydliga förbättringar sågs i patienternas självskattningar efter båda behandlingsmetoderna. Röstbehandling ger således positiva resultat, men några skillnader i behandlingseffekt mellan de två olika metoderna för röstbehandling kunde inte påvisas. / Tube phonation and traditional Swedish voice therapy are two of the most common voice therapy options in Sweden today. As a researcher, it is important to continually evaluate available therapy options to make health care more qualitative and cost effective. Are there differences in treatment effect between these two voice treatments? If so, are the differences so obvious that it is possible to conclude that one treatment should be preferred over the other? Analyses of a patient material, before and after treatment, which included acoustic analysis, perceptual analysis by a group of experienced speech-language therapists and patients' selfassessments were made aiming to answer what effect the two treatment options have in these areas. The patient material consisted of 28 patients, of whom 23 completed the therapy. Twelve of them received treatment with tube phonation while the remaining eleven patients received traditional Swedish voice therapy. Besides audio recordings, the material consisted of patients' self-assessments pre- and post-therapy, including VHI and Swe-VAPP forms. The treatment effect on acoustic parameters was inconclusive. The perceptual parameters aphonia, hyper function, and creaking improved over the entire sample, regardless of the type of voice therapy. Clear improvements were seen in the patients' self-assessments after both therapy methods. Voice therapy thus gives positive results, but no differences in treatment effect between the two different methods of voice therapy were seen.

Stops are one of the most common sounds across languages of the world. Among these pervasive sounds, ejectives form a unique group that is distinguishable from other types of stops. Their particular mechanism of articulation, such as larynx raising and unusually high oral pressure, separates them from the others. More interestingly, a listener perceives them differently and makes a distinction from non-ejective, or pulmonic, stops. What is it that we perceive when hearing ejectives? Do we perceive certain acoustic cues or auditory qualities that are part of their distinctive phonetic nature? Are these phonetic characteristics always distinctive? In other words, is our perception of the ejectives always consistent without any variation at the phonetic level? Motivated by these questions and from my recent exposure to Tsilhqut’in ejectives, I set out to pursue a phonetic investigation of these intriguing sounds. The present study is composed of two main analyses. One is an acoustic analysis that instrumentally examines a dataset of ejective and non-ejective stops in the Tsilhqut’in language with respect to acoustic dimensions such as Voice Onset Time (VOT) in order to compare all the stop classes in terms of their acoustic properties. Such a comparison helps to phonetically characterize the ejectives within the language. The acoustic measures also enable us to compare the characteristics of Tsilhqut’in ejectives with those in other languages, based on previously reported acoustic correlates. In order to determine the characteristics of ejectives across languages, Tsilhqut’in ejectives were compared with ejectives in different languages (e.g., Inguish). The other analysis is auditory, whereby I have examined how I perceived a subset of the ejectives taken out of the whole dataset and compared my auditory judgments with the acoustic measurements in order to find any correlation between results from the two analyses. The findings of the study indicate that Tsilhqut’in ejectives do not follow a traditional binary typology of ejectives. That is, they are neither strong nor weak, as is often claimed in the literature. They are congruent with what recent studies (e.g., Warner 1996) have found of ejectives in other languages – phonetic variability. This means that the dichotomy cannot account for the variability in ejectives at the phonetic level and that an optimal way of classifying ejectives across languages still awaits discovery. To the best of my knowledge, no other phonetic study has been conducted on Tsilhqut’in ejectives prior to the current study. Moreover, there has been little research or documentation carried out on any other phonetic aspects or sounds of this Athabaskan language. I expect that this instrumental study will contribute to the field of linguistics by adding new phonetic knowledge about such a rarely studied language, and I also expect the present study to play a role in the understanding of language learning and of language revitalization around the world.

With the advent of power electronics, inverter-driven induction motor are finding increased use in industries because of applications that demand variable speed operations and because of the potential savings in energy usage. However, these drives sometimes produce unacceptably high levels in vibration and acoustic noise. A literature survey has revealed that while there has been intensive research on the design of inverters to minimize acoustic noise radiation from these drives, the vibro-acoustic behaviour of an induction motor structure has received relatively little attention. The primary objective of this research project, therefore, is to develop a general strategy/algorithm for estimating the acoustic noise radiated from inverter-driven induction motors. By using a three-phase, 2.2 kW induction motor, the vibration modes due to various structural components (such as the rotor, the stator/casing, the endshields and the base plate) of the motor structure were analysed by experimental modal testing. Results indicate that the vibration modes due to the rotor are only important at low frequencies. It has been found that the power injection method gives more accurate measurement of the damping of a motor structure than the modal testing and the time decay methods. If a point force excitation is used, then it is more accurate to measure the sound radiation efficiency than the power conversion efficiency for motor structures. The effect of three different inverter designs (an ideal ???almost sinusoidal??? controller and two commercially available PWM inverters) on the radiated acoustic power were assessed for both no-load and load conditions using sound intensity measurements conducted in an anechoic room. The results indicate that although the sound power level due to aerodynamic and mechanical noise increases at a rate of 12 dB per doubling of the motor speed, the electromagnetic noise dominates at low motor speeds and is still a significant noise source even at high motor speeds. For inverters with low switching frequencies, the radiated sound power level is almost 15 dB higher than the ideal case at low speeds and is relatively insensitive to the motor speed. For inverters that implement the random modulation technique, the change in the total sound power level with the level of the random modulation is very small but the tonal nature of the noise is greatly reduced. The vibration behaviour of a motor structure was modeled using the finite element method (FEM) and validated using the experimental modal testing results. It has been found that it is essential to model the laminated stator as an orthotropic structure. While the details of other structural components (such as the endshields, the teeth in the stator and the windings) are not so important, it is essential that they are incorporated into the structural model as simplified structures to account for their mass, stiffness and boundary conditions imposed on the motor structure. Based on this structural model, the radiated acoustic power for various operating conditions has been predicated using the boundary element (BEM) and the electromagnetic force calculated from an electromagnetic finite element model. The predicted results agree reasonably well with experimental measurements. Despite the success of the FEM/BEM approaches, they can be prohibitively expensive (in terms of computer resources required) to apply to large motors and high frequencies. Thus the feasibility of using a statistical method, namely, the statistical energy analysis (SEA), to estimate the radiated acoustic sound power from an inverter-driven induction motor has been examined. In order to carry out this analysis, analytical expressions for calculating the natural frequencies and radiation efficiency of finite length circular cylindrical shells (which are simplified models of the stator and casing of a motor structure) were firstly derived. The internal loss factors and coupling loss factors of the motor structure were determined experimentally using the power injection method. Then by introducing an equivalent surface mobility of circular cylindrical shells for the electromagnetic force, the vibration response and the acoustic noise radiated from each part of the motor structure were estimated. Results indicate that SEA method is potentially an efficient and effective tool in estimating the noise radiated from inverter-driven induction motors.