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Incorporating information from the short-time phase spectrum into a feature set for automatic speech recognition (ASR) may possibly serve to improve recognition accuracy. Currently, however, it is common practice to discard this information in favour of features that are derived purely from the short-time magnitude spectrum. There are two reasons for this: 1) the results of some well-known human listening experiments have indicated that the short-time phase spectrum conveys a negligible amount of intelligibility at the small window durations of 20-40 ms used for ASR spectral analysis, and 2) using the short-time phase spectrum directly for ASR has proven di?cult from a signal processing viewpoint, due to phase-wrapping and other problems. In this thesis, we explore the possibility of using short-time phase spectrum information for ASR by considering the two points mentioned above. To address the ?rst point, we conduct our own set of human listening experiments. Contrary to previous studies, our results indicate that the short-time phase spectrum can indeed contribute signi?cantly to speech intelligibility over small window durations of 20-40 ms. Also, the results of these listening experiments, in addition to some ASR experiments, indicate that at least part of this intelligibility may be supplementary to that provided by the short-time magnitude spectrum. To address the second point (i.e., the signal processing di?culties), it may be necessary to transform the short-time phase spectrum into a more physically meaningful representation from which useful features could possibly be extracted. Speci?cally, we investigate the frequency-derivative (or group delay function, GDF) and the time-derivative (or instantaneous frequency distribution, IFD) as potential candidates for this intermediate representation. We have performed various experiments which show that the GDF and IFD may be useful for ASR. We conduct several ASR experiments to test a feature set derived from the GDF. We ?nd that, in most cases, these features perform worse than the standard MFCC features. Therefore, we suggest that a short-time phase spectrum feature set may ultimately be derived from a concatenation of information from both the GDF and IFD representations. For best performance, the feature set may also need to be concatenated with short-time magnitude spectrum information. Further to addressing the two aforementioned points, we also discuss a number of other speech applications in which the short-time phase spectrum has proven to be very useful. We believe that an appreciation for how the short-time phase spectrum has been used for other tasks, in addition to the results of our research, will provoke fellow researchers to also investigate its potential for use in ASR.

A novel analytical method is developed to examine the chemical composition of plant oils by electrospray ionisation high-resolution Fourier transform ion cyclotron resonance mass spectrometry in both positive- and negative-ion modes. To date, this is the first reported application of this technique for the study of macadamia nut oil. Samples of macadamia nut oil from the Macadamia Integrifolia- Proteaceae family (smooth shell) are examined. The fatty acid profile of the oil is obtained by this mass spectrometric examination of the transesterified and hydrolysed oil samples. The Fourier transform ion-cyclotron resonance mass spectrometry results are compared to those obtained from similar samples using gas chromatography-mass spectrometry techniques. High performance liquid chromatography and Fourier transform ion cyclotron resonance mass spectrometry are used to separate and assign the isomers present in the methanol extract of the oils in separate experiments. Significant results in this study include: - The first observation and identity of a number of oxidised triacylglycerols in macadamia oil samples. - The first observation of oxidised and free fatty acids, measured directly in hydrolysed oil and in the methanol extract of macadamia oil. - High resolution Fourier transform ion cyclotron resonance mass spectrometry in broadband mode which enables isobars to be observed. - Esterified oil Fourier transform ion cyclotron resonance mass spectrometry results are consistent with our gas chromatography-mass spectrometry results and with the results of similar studies on macadamia oil in the literature. - A number of fatty acids with odd number of carbon atoms are observed in the oil. - In electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry of oils, the sample preparation is straightforward. The sample is dissolved in methanol or acetonitrile and the solution is introduced to the electrospray source directly. Introducing oil samples to the gas chromatograph-mass spectrometer needs the oils to be esterified prior to the analysis. - In this work, state-of-the-art mass spectrometry demonstrates distinct advantages in comparison to gas chromatography measurements such as direct identification of free fatty acids in oil samples, whereas this is not possible in gas chromatography-mass spectrometry due to the required esterification step prior to the analysis. - High performance liquid chromatography fraction collection is combined with Fourier transform ion cyclotron resonance mass spectrometry in off-line mode and found to improve the sensitivity, selectivity and signal to noise levels due to the lower number of compounds in each high performance liquid chromatography fraction compared to the methanol extract of macadamia oil sample. Also isomers of monoacylglycerols have been resolved using the high performance liquid chromatography technique.

Extending the use of Doppler spectroscopy as an important plasma diagnostic -- by developing a multi-channel system capable of tomography -- is the foundation of this thesis. A system which can simultaneously measure the emissivity, temperature and flow velocity of plasma ions has been installed, calibrated and operated on the H-1NF heliac, yielding comprehensive and interesting results. The measurements are time-resolved, made from a large range of viewing positions and, using scalar tomographic inversion methods, can be unfolded to give two-dimensional images of ion emissivity and temperature. The flow velocity profiles, while not inverted, nevertheless lead to a greater understanding of the plasma behaviour.¶ Fifty-five lens-coupled optical fibres, mounted on a large rotatable stainless steel ring, encircle the plasma poloidally and transport light to a multi-channel Fourier-transform spectrometer. This `coherence-imaging' spectrometer employs an electro-optically modulated birefringent crystal plate to monitor the coherence of an isolated spectral line. Measurement of the intensity, fringe visibility and phase of the resulting interferogram leads to values for the emissivity, ion temperature and flow velocity. Using a multi-anode photomultiplier assembly, allows the time-resolved detection of all optical channels simultaneously.¶ The system has been fully calibrated, including a measurement of the spatial response of each line-of-sight. The calibration procedure accounts for the relative channel sensitivities, the response of the line filter and the removal of detector cross-talk. In situ light sources are installed provide routine and accurate relative intensity calibration of the system.¶ Methods of tomography provide the unfolding of the measured plasma parameters to construct two-dimensional images of ion temperature and emissivity. Methods of inversion include the iterative ART routine -- using projection data gathered with the light-collecting optics rotated to different viewing positions -- and linear composition of Fourier-Bessel basis functions -- with the data obtained from a single unrotated viewing position. ART reconstructions of the emissivity are performed without the need for a priori information while those of the ion temperature are computed using regularising functions to help stabilise the inversion.¶ This new system -- named ToMOSS for Tomographic Modulated Optical Solid-state Spectrometer -- enables a more detailed study of various plasma phenomena observed in H-1NF. Among other results, this thesis presents the first tomographic reconstructions of emissivity and temperature fluctuations associated with a large-scale coherent instability.

Good tone is one of an alto saxophone player's greatest assets and consequently deserves high priority in training and pedagogy. The current pedagogical literature gives little attention to tone production on the saxophone. The mouthpiece is the link between the player and the saxophone. This study examined the effect of the normal mouthpiece pitch and the pitch range produced on the saxophone mouthpiece on alto saxophone tone quality . In this experimental study, recordings were made of forty-three student alto saxophone players who performed tasks consisting of three saxophone mouthpiece exercises and four short musical phrases on the saxophone. The tape recordings were used to provide a spectral analysis of the tone samples by Fast Fourier Transform Analysis, and to allow qualitative analysis by five expert judges. The judges used a saxophone listening profile to provide qualitative evaluation of the recordings. Cluster analysis produced three groups of subjects according to combinations of the mouthpiece pitch and range produced. The mean sustained mouthpiece pitch and mouthpiece range of the groups were: Cluster 1 - 790 Hz and 550 cents; Cluster 2 1023 Hz and 150 cents: and Cluster 3 - 820 Hz and 1203 cents. Analysis of variance was used to test for statistically significant differences between the clusters. Discriminant analysis was used to identify other variables which contributed to the formation of the three clusters. The quantitative analysis of both mouthpiece and saxophone tones provided no insight into the spectra of the student subjects. The qualitative analysis using bipolar descriptors provided valid criteria which could be applied consistently for the analysis of student saxophone tone. A Tonal Index was computed from the judges' ratings in order to test for differences in tone between the clusters. Analysis of variance tests showed significant differences in the tone produced by the clusters on both the mouthpiece and the saxophone. The tone produced by Cluster 3 was significantly different to that produced by Clusters 1 and 2 at the p < .05 level. Discriminant analysis identified the use of saxophone tone models (through comparative critical listening) and small group performance as significant predictor variables (at the p < .05 level) in the formation of the clusters. The results of this study suggest that tone production on the alto saxophone is improved through the development of control on the mouthpiece. It was concluded that routine practice with the mouthpiece can serve in the development of a flexible and responsive embouchure and oral cavity and that students need to develop a mental concept of saxophone tone as part of the development of tone production. Also, experience in small group performance needs to be sought and provided for saxophone students. Finally, this study focussed on an area of mouthpiece behaviour which can easily be included into any instructional design and monitored by teachers.

Thesis (Ph. D.)--Ohio State University, 2006. / Full text release at OhioLINK's ETD Center delayed at author's request

This thesis depends on the paper &lsquo / Non-Boolean Almost Perfect Nonlinear Functions on Non- Abelian Groups&rsquo / by Laurent Poinsot and Alexander Pott and we have no new costructions here. We give an introduction about character theory and the paper of Poinsot and Pott, and we also compare previous definitions of bent functions with the definition of the bent function in the paper. As a conclusion, we give new theoretical definitions of bent, PN, APN ana maximum nonlinearity. Moreover, we show that bent and PN functions are not always same in the non-abelian cases.

A high-resolution infrared Fourier Transform Spectrometer (FTS) has been operational at the Toronto Atmospheric Observatory (TAO)since May 2002. An optimal estimation retrieval technique is used to analyse the observed spectra and provide regular total and partial column measurements of trace gases in the troposphere and stratosphere as part of the Network for the Detection of Atmospheric Composition Change. The quality of these results were assessed through two ground-based validation campaigns, comparisons with three satellite instruments, and comparison with a three-dimensional chemical transport model. The two ground-based campaigns involved two lower-resolution FTS instruments: the University of Toronto FTS and the Portable Atmospheric Research Interferometric Spectrometer for the Infrared. The first campaign took place over the course of four months and is the longest side-by-side intercomparison of ground-based FTS instruments, to date. The second campaign was more focused and involved all three instruments measuring over a two-week period. Simultaneous measurements of O3, HCl, N2O, and CH4 were recorded and average total column differences were all < 3.7% in the extended campaign, and < 4.5% in the focused campaign. Satellite-based comparisons were done with the SCanning and Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY), the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS), and the Optical Spectrograph and InfraRed Imager System (OSIRIS). Total column CO, CH4, and N2O compared with SCIAMACHY all had average differences < 10% with results from the TAO-FTS being as good as, or better, than that of other instruments. Validation with the ACE-FTS showed that average partial columns of O3, NO2, N2O, CH4, and HCl were within 10% while observations of CO and NO each had an average bias of about 25%. Comparisons of monthly average partial column O3 and NO2 with OSIRIS were highly correlated (R = 0.82-0.97) with monthly mean differences of < 3.1% for O3 and < 2.6% for NO2. Finally, comparisons with the GEOS-Chem chemical transport model revealed that the model consistently over-estimates tropospheric columns of CO and C2H6 observed at TAO. It was determined that the enhanced CO values were partially due to the North American emissions specified in the model, but more work must be done in the future if the source of this discrepancy is to be fully explained.

A linear periodically time-varying (LPTV) system is a linear time-varying system with the coefficients changing periodically, which is widely used in control, communications, signal processing, and even circuit modeling. This thesis concentrates on identification of LPTV systems. To this end, the representations of LPTV systems are thoroughly reviewed. Identification methods are developed accordingly. The usefulness of the proposed identification methods is verified by the simulation results.<p> A periodic input signal is applied to a finite impulse response (FIR)-LPTV system and measure the noise-contaminated output. Using such periodic inputs, we show that we can formulate the problem of identification of LPTV systems in the frequency domain. With the help of the discrete Fourier transform (DFT), the identification method reduces to finding the least-squares (LS) solution of a set of linear equations. A sufficient condition for the identifiability of LPTV systems is given, which can be used to find appropriate inputs for the purpose of identification.<p> In the frequency domain, we show that the input and the output can be related by using the discrete Fourier transform (DFT) and a least-squares method can be used to identify the alias components. A lower bound on the mean square error (MSE) of the estimated alias components is given for FIR-LPTV systems. The optimal training signal achieving this lower MSE bound is designed subsequently. The algorithm is extended to the identification of infinite impulse response (IIR)-LPTV systems as well. Simulation results show the accuracy of the estimation and the efficiency of the optimal training signal design.

A fixed terrestrial wireless system such as the Microwave Multi-channel Distribution Service (MMDS) can be used as the ``last mile' to provide a high speed Internet connection from a base station to a home in a rural or suburban residential area. Such a broadband wireless system works very well under line-of-sight transmission. It works quite well even if the line-of-sight is obstructed with a large number of trees. However, when trees obstruct the line-of-sight, under conditions of wind, the user may experience loss of the RF signal from time to time. This is especially true under gusty conditions. As part of this research a high precision DSP-based measuring system is devised to accurately measure and characterize the distortions caused by tree foliage on the RF line-of-sight signal. The approach is to digitally generate a signal composed of several tones, up-convert the signal to 2.5 GHz and send it through tree foliage to a receiver where the signal is down-converted and sampled for a duration of five seconds. The samples collected are processed using Matlab to compute the temporal amplitude and phase variations of the tones. The measurement system provides estimates of the amplitude and phase of the receive tones with a time resolution of 3.2 ms. The standard deviation of the amplitude estimates is 0.3\% of the actual amplitude of the tones and the standard deviation of the phase estimates is 0.23 degree. This accuracy is obtained when the signal-to-noise ratio of the receive signal is greater than 20 dB. Measurement in the field with tree foliage in the line-of-sight shows that the swaying of the branches in the wind can cause rapid signal fading. This research determines the type of fade, the depth and duration of the fade, as well as the fading rate.