UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

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    3D Multimodal Image Registration: Application to equine PET and CT images
    (2017) Regani, Sai Deepika; Chellappa, Rama; Beylin, David; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Positron Emission Tomography (PET) is being widely used in veterinary medicine in recent years. Although it was limited to small animals because of its classical design and the large amount of radionuclide doses required, PET imaging in horses became possible with the introduction of a portable PET scanner developed by Brain Biosciences Inc. It was observed that this new modality could capture abnormalities like lesions that Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and other modalities could not. Since 2016, PET imaging in horses is being studied and analysed. While PET provides functional information characterizing the activity of lesions, it is useful to combine information from other modalities like CT and match the structural information to develop an accurate spatial representation of the data. Since biochemical changes occur much earlier than structural changes, this helps detect lesions and tumours during the early stages. Multimodal image registration is used to achieve this goal. A series of steps are proposed to automate the process of registration of equine PET and CT images. Multimodal image registration using landmark-based and intensity-based techniques are studied. It is observed that a few tissues are not imaged in the PET, which makes image segmentation, an important preprocessing step in the registration process. A study of the segmentation algorithms relevant to the field of medical imaging is presented. The performance of segmentation algorithms improved with the extent of manual interaction and intensity-based registration gave the smallest time complexity with reasonable accuracy.
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    Teaching Registration in the Mixed Choral Rehearsal: Physiological and Acoustical Considerations
    (2011) Aldrich, Nicole Paige; Maclary, Edward; Music; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    One of the most challenging concepts of vocal technique is registration. In classical Western singing, noticeable changes of timbre over the course of a singer's vocal range are considered undesirable, and much effort is spent in learning how to eliminate these "breaks." Faults in vocal registration can cause unevenness of tone quality, lack of resonance, and instability of intonation. The choral conductor must learn how to address these problems in rehearsal in order to establish good choral sound. Much literature exists which defines the physiological and acoustical adjustments required to create a well-blended, "one-register" voice; however, this literature is aimed at the individual singer or teacher of solo voice. Voice-training resources for choral conductors may mention registration and vowel modification but typically do not explain in any detail the science underlying the concepts. The choral conductor thus must adapt the body of solo voice research for application to a group voice teaching setting. The primary goal of this paper is to propose and describe techniques for teaching registration and vowel modification concepts to choral singers. The paper details the physiological factors at work in vocal registration, including the functions of the intrinsic laryngeal musculature. It also surveys the science of acoustics as it applies to the singing voice, including a discussion of vowel formants and the purposes and methods of formant tuning for male and female voices. This section will draw heavily on existing research in solo singing. The next portion of the paper tailors this knowledge to the needs of the choral vocal teacher. The author describes signs of registration difficulties within an ensemble and their possible causes. Next the author provides a series of vocalises and other tools designed to help the conductor achieve two goals in rehearsal: first, to help both men and women develop the physiological adjustments necessary to reduce obvious registration shifts; and second, to assist singers of all voice types in discovering the vowel modifications which will produce a uniform tone quality throughout the range. Finally, the author explains how the conductor can identify potential registration problems during score study and preparation.