Since the early sixteenth century, the bassoon has played a role of varying importance in musical organizations. Early groups used as many as twenty-four bassoons in conjunction with other instruments. Today, it is common to have no more than two or three bassoons in bands and orchestras because other instruments, as they developed, have replaced the bassoon in the instrumentation of such groups. Although the bassoon is not as important numerically as it formerly was, its place in musical organizations is assured because it has expressive colors and tonal qualities which cannot be duplicated by any other instrument. The bassoon is especially important as a bass instrument in small ensembles.

The commercialization of wide band-gap devices such as silicon carbide and gallium nitride transistors has made it possible for power electronics applications to achieve unprecedented performance in terms of efficiency and power density. However, the device characteristics which make this performance possible also create secondary consequences in these high-performance applications. One such consequence which is particularly difficult to manage in the context of power electronics applications is the occurrence of self-sustained oscillation. This problem has been recognized in the power electronics literature, but heretofore has not received an extensive analytical treatment. This dissertation provides a comprehensive analytical treatment of the self-sustained oscillation phenomenon, logically separated into two components: an initial forced cycle and the subsequent oscillatory behavior. A large-signal model has been developed in order to predict the occurrence of the initial forced cycle based on a set of estimated initial conditions derived from a user-specified operating point. The establishment of the initial forced cycle as predicted by the large-signal model creates the bias conditions necessary for the analytical treatment of the subsequent oscillatory behavior. For this purpose, a small-signal model is presented which describes this phenomenon on the basis of recognizing the wide band-gap device and a minimal set of parasitic components associated with the gate and drain circuits as an unintended negative conductance oscillator. In the context of established oscillator design theory it has been shown both analytically and with simulation that negative differential conductance exhibited by the parasitic model explains the conditions under which self-sustained oscillation is likely to occur. Both the large-signal and small-signal models are shown to demonstrate good agreement with empirical results from pulsed switching experiments obtained over a wide range of operating conditions. In addition, a catalog of known solutions to the problem of self-sustained oscillation is presented, along with a discussion of a method by which the current work can be used by application designers to preclude the occurrence of this phenomenon in practical systems by design.

The increasing demand for efficient cancer treatment inspired the researchers for new investigations about an alternative treatment of cancer. Microwave ablation is the newest ablation technique to cure cancer. This method is minimally noninvasive and inexpensive compared to the other methods. However, current microwave ablation systems suffer due to narrowband nature of the antenna (dipole or slot) placed at the tip of the probe. Therefore, this study developed an ultra-wideband ablation probe that operates from 300MHz to 10 GHz. For this purpose, a small wideband antenna is designed to place at the tip of the probe and fabricated. These probes are tested at ISM frequencies (2.4 GHz and 5.8GHz) in skin mimicking gels and pig liver. Microwave ablation probe design, simulation results, and experiment results are provided in this thesis.

In this dissertation, dimensionality reduction for hyperspectral remote sensing imagery is investigated to alleviate practical application difficulties caused by high data dimension. Band selection and band clustering are applied for this purpose. Based on availability of object prior information, supervised, semi-supervised, and unsupervised techniques are proposed. To take advantage of modern computational architecture, parallel implementations on cluster and graphics processing units (GPU) are developed. The impact of dimensionality reduction on the following data analysis is also evaluated. Specific contributions are as below. 1. A similarity-based unsupervised band selection algorithm is developed to select distinctive and informative bands, which outperforms other existing unsupervised band selection approaches in the literature. 2. An efficient supervised band selection method based on minimum estimated abundance covariance is developed, which outperforms other frequently-used metrics. This new method does not need to conduct classification during band selection process or examine original bands/band combinations as do traditional approaches. 3. An efficient semi-supervised band clustering method is proposed, which uses class signatures to conduct band partition. Compared to traditional unsupervised clustering, computational complexity is significantly reduced. 4. Parallel GPU implementations with computational cost saving strategies for the developed algorithms are designed to facilitate onboard processing. 5. As an application example, band selection results are used for urban land cover classification. With a few selected bands, classification accuracy can be greatly improved, compared to the one using all the original bands or those from other frequently-used dimensionality reduction methods.

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Symphony for Band is a composition in three movements following a fast, slow, fast tempo scheme; the work is approximately sixteen minutes in duration. The standard band instrumentation is augmented by the addition of C trumpets, flugelhorns, an English horn, and a piano. The timbre of these instruments is explored both in a soloistic manner and in varying instrumental sombinations.

III-nitride semiconductors have garnered significant attention due to their diverse applications in the fields of optics and electronics. As GaN-based visible light-emitting diodes (LEDs) and laser technologies continue to advance, there has been a surge of interest in the development of ultraviolet (UV) devices. In order to explore the UV range, extensive research has been conducted on BN-based materials and their alloys with conventional III-nitrides, driven by the quest for materials exhibiting larger bandgaps and enhanced refractive index contrast. Additionally, the incorporation of boron into III-nitrides through alloying provides a promising avenue for effectively modulating lattice parameters and manipulating the crystalline structure. This offers a novel approach for strain engineering, lattice matching, and structural manipulation, facilitating the optimization of device performance and expanding the capabilities of III-nitride semiconductors in the realm of UV device development. In this work, we optimize and investigate the epitaxial growth of BGaN using metalorganic chemical vapor deposition, and characterize the physical and electronic properties of the grown films using several techniques such as X-ray diffraction, atomic force microscopy, UV-Visible spectroscopy, X-ray Photoelectron Spectroscopy (XPS), electron energy loss spectroscopy (EELS) and more. We have explored different metalorganic chemical vapor deposition techniques —such as continuous growth and pulsed-flow modulation, high temperature and low temperature growths, hydrogen-containing and hydrogen-free growths, trimethylgallium (TMG) and triethylgallium (TEG) sourced growths, Triethylborane (TEB) and borazine (BRZN) sourced growths— to grow BGaN alloys. Samples grown using continuous-flow method, low temperatures, TEG source and hydrogen-free carrier gas show higher boron content and better crystalline quality when having TEB as a boron source. BRZN is used to reduce carbon impurities for the purpose of film doping. With BRZN, TMG was found as a preferred gallium source. Additionally, we have characterized the electronic properties of the grown films in details using XPS, EELS and other related techniques. We have studied the band offset of BGaN with AlN using traditional methods. Furthermore, we have developed a statistical technique to find small offsets at interfaces at the precision of the measuring instrument.

The composition is in two movements played continuously, and requires approximately eleven minutes for performance. The two movements offer different treatment of similar thematic material. Unifying devices are used in each movement. Instrumentation includes the following: piccolo, two flutes, two oboes, two Bb clarinets, F English horn, Bb bass clarinet, two bassoons, two Eb alto saxophones, Bb tenor saxophone, Eb baritone saxophone, two bb trumpets, three F French horns, two trombones, euphonium, tuba, and three percussion.

The Communications industry is currently involved in a wireless revolution. Consequently, there is a need for a wide variety of wireless solutions to replace existing wired systems. The major systems, such as cellular and satellite, are costly to put in place and require a low BER (bit error rate) to be successful for their real-time applications. In contrast to this are those systems that can tolerate a higher BER as a trade off for cost (<$50.00) and complexity. A typical application for these lower cost systems is monitoring non-critical data that is not required to be delivered real-time. The work presented here focused on designing, building and testing a Proof of Concept Prototype (POCP) for a low-cost wireless data link (WDL). In a typical WDL application, problems arise when too large a data rate attempts to travel the allotted channel bandwidth in the frequency band of interest. Also, limitations imposed by current radio transceiver technology tend to limit WDL design. The existing sponsor's wired system operates at a 9600 Baud, and presented the opposite problem: the data rate was too low for the RF Microdevices RF2905 used for the POCP. This challenge necessitated the development of a low-cost encoding scheme using standard digital logic gates in place of more costly Manchester Encoding. For the digital logic encoding scheme to work, the crystal oscillators had to be modified. This resolved the problem with the low frequency limitations of the RF2905 phase locked-loop. In addition, the polled, asynchronous, and unbalanced RS485 connections of the wired system had to be adapted to interface with the single-ended data connections of the WDL. Finally, the successful design of a timing scheme, using standard TTL components and balanced to unbalanced drivers, resolved the interface problems resulting in a low-cost WDL designed to operate with an existing wired system without requiring modifications to that system. The WDL is transparent in connection and operation and can be inserted without disrupting the current wired system. / Master of Science

We consider the problem of narrow-band signal detection in a passive sonar environment. The collected signals are passed to a fast Fourier Transform (FFT) delay-sum beamformer. In classical signal detection, the output of the FFT spectrum analyser in each frequency bin is the signal power spectrum which is used as the signal feature for detection. The observed signal power is compared to a locally estimated mean noise power and a log likelihood ratio test (LLRT) can then be established. In this thesis, we propose the use of the power spectral density (PSD) matrix of the spectrum analyser output as the feature for detection due to the additional cross-correlation information contained in such matrices. However, PSD matrices are structurally constrained and therefore form a manifold in the signal space. Thus, to find the distance between two matrices, the measurement must be carried out using Riemannian distance (RD) along the tangent of the manifold, instead of using the common Euclidean distance (ED). In this thesis, we develop methods for measuring the Frechet mean of noise PSD matrices using the RD and weighted RD. Further, we develop an optimum weighting matrix for use in signal detection by RD so as to further enhance the detection performance. These concepts and properties are then used to develop a decision rule for the detection of narrow-band sonar signals using PSD matrices. The results yielded by the new detection method are very encouraging. / Thesis / Master of Applied Science (MASc)