There has been in the past and still is controversy over the genesis of the third heart sound (S3). Recent studies, strongly suggest that S3 is a manifestation of a sudden intrinsic limitation in the expansion of the left ventricle. The thesis has aimed to explore that hypothesis further using combined echocardiographic and spectral analysis techniques. Spectral analysis was carried out via conventional fast fourier transform methods and the maximum entropy method. The efficacy of these techniques, in relation to clinical and scientific application, was explored further. Briefly discussed was the application of autoregressive-moving average (ARMA) modelling for spectral analysis of S3, in relation to further work. Following is a brief synopsis of the thesis: CHAPTER 1 This gives an historical and general introduction to heart sound analysis. Discussed briefly is the physiology of the heart and heart sounds and the diagnostic implications of S3 analysis. CHAPTER 2 Here is discussed the instrumentation system used and phonocardiographic and echocardiographic data aquisition. Data preprocessing and storage is also covered. CHAPTER 3 In this chapter the application of a FFT method and correlation of resultant spectral parameters with echocardiographic parameters is reported. CHAPTER 4 The theoretical development of the maximum entropy technique (based on published papers and expanded) is discussed here. Numerical experiments with the method and associated problems are also discussed. CHAPTER 5 The MEM is applied to the spectral analysis of S3 and compared with the FFT method. Correlation analysis of MEM derived spectral parameters with echocardiograhic data is performed. CHAPTER 6 Here ARMA modelling and application to further work is discussed. An ARMA model from the maxixum entropy coefficients is derived. The application of this model to the deconvolution of the chest wall transfer function is discussed as an approach for further work. / Thesis (M.Sc.)--School of Mathematical Sciences, 1989.

This study examines the significance of sounds and silence in Joseph Conrad’s novella Heart of Darkness (1902). The importance of visual effects has repeatedly been analyzed and therefore, it is high time to explore the text from an auditory perspective. By comparing and contrasting Victorian city sounds to sounds in the wilderness, I show that the urban and rural worlds have a great deal in common. Furthermore, by deconstructing the seemingly stable binary opposition of sound and silence as well as that of civilization and wilderness, it becomes evident that they are related and depend on one another. This paper also examines noise and how it is used as a means of power. Moreover, it deals with Thomas Edison’s invention, the phonograph, as an implicit discursive device in the text. In conclusion, it is argued that the sonic environment is of high significance and should therefore not be ignored and readers must try to close their eyes in order to hear what is said.

Recent theoretical and experimental studies have demonstrated that an estimate of the Green's function between two hydrophones can be extracted passively from the cross‐correlation of ambient noise recorded at these two points. Hence monitoring the temporal evolution of these estimated Green's functions can provide a means for noise‐based acoustic tomography using a distributed sensor network. However, obtaining unbiased Green's function estimate requires a sufficiently spatially and temporally diffuse ambient noise field. Broadband ambient noise ([200 Hz-20 kHz]) was recorded continuously for 2 days during the SWAMSI09 experiment (next to Panama City, FL) using two moored vertical line arrays (VLAs) spanning 7.5m of the 20‐m water column and separated by 150 m. The feasibility of noise‐based acoustic tomography ([300-1000 Hz]) was assessed in this dynamic coastal environment over the whole recording period. Furthermore, coherent array processing of the computed ocean noise cross‐correlations between all pairwise combinations of hydrophones was used to separate acoustic variations between the VLAs caused by genuine environmental fluctuations-such as internal waves-from the apparent variations in the same coherent arrivals caused when the ambient noise field becomes strongly directional, e.g., due to an isolated ship passing in the vicinity of the VLAs.

Thesis (M.S.)--University of North Carolina at Wilmington, 2002. / Includes bibliographical references (leaves : [49]-50).

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 275-293).

Η στηθοσκόπηση για την παρακολούθηση της λειτουργίας της καρδιάς αποτελεί ένα από τα κύρια εργαλεία για την παρακολούθηση της υγείας τους τελευταίους δύο αιώνες περίπου. Δυστυχώς όμως παρά τη ραγδαία ανάπτυξη στον τομέα των ενσωματωμένων συστημάτων, καθώς και στην επεξεργασία σημάτων που προέρχονται από τη λειτουργία του καρδιοαναπνευστικού συστήματος, ο έλεγχος της λειτουργίας του τελευταίου παραμένει μια αρκετά χρονοβόρα και υποκειμενική διαδικασία, αφού σε καθημερινή εφαρμογή γίνεται με μη αυτοματοποιημένο τρόπο. Στα πλαίσια αυτής της εργασίας μελετήθηκε η φωνοκαρδιογραφία, της οποίας αντικείμενο αποτελεί η καταγραφή και επεξεργασία των καρδιακών ήχων και αναπτύχθηκε ένα σύστημα παρακολούθησης των ζωτικών ενδείξεων της καρδιάς και των πνευμόνων, όπως αυτές προκύπτουν μέσω του φωνοκαρδιογραφικού σήματος. Η εργασία ξεκίνησε ως μελέτη της λειτουργίας της καρδιάς, της μορφής των καρδιακών σημάτων και μεθόδων παρακολούθησής τους, καθώς και μέθοδοι υλοποίησης τέτοιων συστημάτων. Ακόλουθα μελετήθηκαν η χρήση και οι δυνατότητες των σύγχρονων ενσωματωμένων συστημάτων και μικροελεγκτών και ιδιαίτερα ο μικροελεγκτής ADuC7026 της Analog Devices, που ήταν και ο μικροελεγκτής που χρησιμοποιήθηκε κατά την υλοποίηση. Για την υλοποίηση χρησιμοποιήθηκε προσεγγιστικό σήμα, για τη μοντελοποίηση αυτού που προσλαμβάνεται από έναν αισθητήρα κατά τη λειτουργία του καρδιοαναπνευστικού συστήματος. Για την επεξεργασία του σήματος μελετήθηκαν και χρησιμοποιήθηκαν ψηφιακά φίλτρα πεπερασμένης κρουστικής απόκρισης (FIR). Η υλοποίηση του συστήματος έγινε σε πέντε στάδια. Αρχικά υλοποιήθηκε εφαρμογή για τον έλεγχο της ορθής λειτουργίας του αναπτυξιακού κυκλώματος της Olimex ADuC-P7026. Στη συνέχεια αναπτύχθηκε η τελική εφαρμογή σε τέσσερα διακριτά στάδια. Στο πρώτο οι υπολογισμοί έγιναν με βάση τη μέση τιμή του σήματος εισόδου, για την απομάκρυνση των σταθερών (dc) συνιστωσών του. Στο δεύτερο στάδιο χρησιμοποιήθηκε υψιπερατό FIR φίλτρο για την αποκοπή της σταθερής συνιστώσας. Στο τρίτο στάδιο χρησιμοποιήθηκε ζωνοδιαβατό FIR φίλτρο για την αποκοπή του θορύβου που οφείλεται στις συχνότητες που είναι μεγαλύτερες αυτής του πληροφοριακού σήματος και για την απαλλαγή του σήματος από σταθερές συνιστώσες. Στο τέταρτο στάδιο της εφαρμογής έγινε πλέον δυνατός ο εντοπισμός καρδιακών ήχων. Κατά την ανάπτυξη της εφαρμογής χρησιμοποιήθηκε το περιβάλλον ανάπτυξης εφαρμογών της Keil, μVision 3. Ο προγραμματισμός του μικροελεγκτή έγινε σε γλώσσα προγραμματισμού C. / -

An approximate of the Green's function can be obtained by taking the cross-correlation of ambient noise that has been simultaneously recorded on separate sensors. This method is applied for two experiments, which illustrate the advantages and challenges of this technique. The first experiment is in the ultrasonic regime [5-30] MHz and uses capacitive micromachined ultrasonic transducer arrays to image the near field and compares the passive imaging to the conventional pulse-echo imaging. Both the array and target are immersed in a fluid with the sensors recording the fluid's random thermal-mechanical motion as the ambient noise. The second experiment is a passive ocean monitoring experiment, which uses spatiotemporal filtering to rapidly extract coherent arrivals between two vertical line arrays. In this case the ambient noise in the frequency band [250 1500] Hz is dominated by non-stationary shipping noise. For imaging purposes, the cross-correlation needs to extract the Green's function so that the imaging can be done correctly. While for monitoring purposes, the important feature is the change in arrivals, which corresponds to the environment changing. Results of both experiments are presented along with the advantages of this passive method over the more accepted active methods.

Snoring is a highly prevalent disorder affecting 20-40% of adult population. Snoring is also a major indicative of obstructive sleep apnea (OSA). Despite the magnitude of effort, the acoustical properties of snoring in relation to physiological states are not yet known. This thesis explores statistical properties of snoring sounds and their association with OSA. First, an unsupervised technique was developed to automatically extract the snoring sound segments from the lengthy recordings of respiratory sounds. This technique was tested over 5665 snoring sound segments of 30 participants and the detection accuracy of 98.6% was obtained. Second, the relationship between anthropometric parameters of snorers with different degrees of obstruction and their snoring sounds’ statistical characteristics was investigated. Snoring sounds are non-Gaussian in nature; thus second order statistical methods such as power spectral analysis would be inadequate to extract information from snoring sounds. Therefore, higher order statistical features, in addition to the second order ones, were extracted. Third, the variability of snoring sound segments within and between 57 snorers with and without OSA was investigated. It was found that the sound characteristics of non-apneic (when there is no apneic event), hypopneic (when there is hypopnea), and post-apneic (after apnea) snoring events were significantly different. Then, this variability of snoring sounds was used as a signature to discriminate the non-OSA snorers from OSA snorers. The accuracy was found to be 96.4%. Finally, it was observed that some snorers formed distinct clusters of snoring sounds in a multidimensional feature space. Hence, using Polysomnography (PSG) information, the dependency of snoring sounds on body position, sleep stage, and blood oxygen level was investigated. It was found that all the three variables affected snoring sounds. However, body position was found to have the highest effect on the characteristics of snoring sounds. In conclusion, snoring sounds analysis offers valuable information on the upper airway physiological state and pathology. Thus, snoring sound analysis may further find its use in determining the exact state and location of obstruction.

The noise coming from wind power development can be an environmental impact forthe surrounding communities. It is well known that the main wind turbine noise iscaused by the movement of the turbine wings through the air. However, there areuncertainties about the importance of machinery sounds and possible variations amongwind turbines. A high resolution acquisition system was used to perform a fieldexperiment comparison of the noise spectra from some wind turbines at Laholm(Sweden). The results have shown different band spectra peaks associated to machinerysounds among wind turbines from the same model and also from those of differentmanufactures. Maintenance conditions of these wind turbines could explain thedifferences in intensity and frequency locations of the band spectra peaks found. Inorder to know the importance for human audition of these peaks, listening test or doseresponsestudies would be needed to provide relevant information in this regard. Themethodology developed in this study is suggested to be useful for identifying certainmachinery failures which could corrupt the noise sounds emitted at certain wind turbinelocations.

The social environment we live in today is exceptionally informal. In the past the type of language the learners used, as well as their spelling ability, gave an indication of the type of education they had received. In present times, it often occurs that people are judged according to their spelling ability to determine whether the specific person is suitable for a certain career. People only realise the importance of writing and spelling correctly once they have completed their studies and started working (often this is too late).This leads to distress and problem situations in universities and schools because learners cannot read and spell. Because of globalization, young people today regard English as the global language. This opens doors for them and the use of English is becoming easier. The result is that Afrikaans is also becoming more informal and this is expressed in the learners' writing and spelling ability. Learners' spelling therefore is atrocious. Decline in language and spelling usage is the result of little (or no) education in spelling in general and also because learners give so little attention to reading lately. Research indicates that students and learners experience the "no rules" of poor spelling (also due to SMS language) as a freeing experience and they do not realise the seriousness of speaking, writing and reading standard Afrikaans. The youth regard this era we live in as "cool" and they believe that it protects them against the embarrassment of poor spelling. A finger is often pointed at educators because learners can no longer read and spell. Educators complain that learners have a "couldn't care less" attitude towards correct spelling. Learners use a telegram style for writing, and poor spelling increasingly occurs in creative writing. They ruin their writing skills with bad spelling. Learners no longer have a general knowledge of spelling words and in this way their poor spelling skills are further weakened. "Upsetting spelling problems" originate because learners are not made aware of the phonemes of sounds from an early age and educators are ignorant of how to develop these awareness skills in learners. In the light of these statements one would expect that educators would have received the necessary guidance concerning spelling methods and strategies for teaching and educating spelling. However, the opposite is true as indicated in the literature, namely that educators often have to depend on their own experience to develop several aspects, for instance to develop phonemic awareness in learners so as to ensure success in spelling. Educators discuss learners, their own successes, etcetera but they never discuss the methods they use. The young and inexperienced educator must depend on book-knowledge, personal initiatives, trial and error as well as spontaneous methods to teach spelling. In this study, attention is focused on the link between phoneme awareness and the spelling ability of learners, especially in the Foundation Phase. To achieve the aim of this study the spelling ability of a group of Grade 3 learners was studied using various tests over a certain period of time. The results showed that learners who have no or very little phonemic awareness also do not possess the necessary spelling skills. This study indicates the importance of phonemic awareness as determinant for good spelling. Consequently a definite link exists between phonemic awareness and spelling. From the empirical study that was conducted it became very clear that the level of phonemic awareness and spelling achievement is determined by the education process and the involvement of the educator. Valid theoretical principles were discussed to highlight the necessity of this aspect. Language gatekeepers and educators, especially in the Foundation Phase, thus have an enormous task to develop phoneme awareness from an early age in learners so that they can become aware of the importance of correct spelling. / Thesis (M.Ed.)--North-West University, Potchefstroom Campus, 2008.