Theses and Dissertations from UMD
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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 give thesis/dissertation in DRUM
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Item AI Empowered Music Education(2024) Shrestha, Snehesh; Aloimonos, Yiannis; Fermüller, Cornelia; Computer Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Learning a musical instrument is a complex process involving years of practice and feedback. However, dropout rates in music programs, particularly among violin students, remain high due to socio-economic barriers and the challenge of mastering the instrument. This work explores the feasibility of accelerating learning and leveraging technology in music education, with a focus on bowed string instruments, specifically the violin. My research identifies workflow gaps and challenges for the stakeholders, aiming to address not only the improvement of learning outcomes but also the provision of opportunities for socioeconomically challenged students. Three key areas are emphasized: designing user studies and creating a comprehensive violin dataset, developing tools and deep learning algorithms for accurate performance assessment, and crafting a practice platform for student feedback. Three fundamental perspectives were essential: a) understanding the stakeholders and their specific challenges, b) understanding how the instrument operates and what actions the player must master to control its functions, and c) addressing the technical challenges associated with constructing and implementing detection and feedback systems. The existing datasets were inadequate for analyzing violin playing, primarily due to their lack of diversity of body types and skill levels, as well as the absence of well-synchronized and calibrated video data, along with corresponding ground truth 3D poses and musical events. Our experiment design was ensured that the collected data would be suitable for subsequent tasks downstream. These considerations played a significant role in determining the metrics used to evaluate the accuracy of the data and the success metrics for the subsequent tasks. At the foundation of movement analysis lies 3D human pose estimation. Unfortunately, the current state-of-the-art algorithms face challenges in accurately estimating monocular 3D poses during instrument playing. These challenges arise from factors such as occlusions, partial views, human-object interactions, limited viewing angles, pixel density, and camera sampling rates. To address these issues, we developed a novel 3D pose estimation algorithm based on the insight that the music produced by the violin is a direct result of the corresponding motions. Our algorithm integrates visual observations with audio inputs to generate precise, high-resolution 3D pose estimates that are temporally consistent and conducive to downstream tasks. Providing effective feedback to learners is a nuanced process that requires balancing encouragement with challenge. Without a user-friendly interface and a motivational strategy, feedback runs the risk of being counterproductive. While current systems excel at detecting pitch and temporal misalignments and visually displaying them for analysis, they often overwhelm players. In this dissertation, we introduce two novel feedback systems. The first is a visual-haptic feedback system that overlays simple augmented cues on the user's body, gently guiding them back to the correct posture. The second is a haptic band synchronized with the music, enhancing students' perception of rhythmic timing and bowing intensities. Additionally, we developed an intuitive user interface for real-time feedback during practice sessions and performance reviews. This data can be shared with teachers for deeper insights into students' struggles and track progress. This research aims to empower both students and teachers. By providing students with feedback during individual practice sessions and equipping teachers with tools to monitor and tailor AI interventions according to their preferences, this work serves as a valuable teaching assistant. By addressing tasks that teachers may not prefer or physically perform, such as personalized feedback and progress tracking, this research endeavors to democratize access to high-quality music education and mitigate dropout rates in music programs.Item TOWARDS EFFECTIVE DISPLAYS FOR VIRTUAL AND AUGMENTED REALITY(2020) Sun, Xuetong; Varshney, Amitabh; Computer Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Virtual and augmented reality (VR and AR) are becoming increasingly accessible and useful nowadays. This dissertation focuses on several aspects of designing effective displays for VR and AR. Compared to conventional desktop displays, VR and AR displays can better engage the human peripheral vision. This provides an opportunity for more information to be perceived. To fully leverage the human visual system, we need to take into account how the human visual system perceives things differently in the periphery than in the fovea. By investigating the relationship of the perception time and eccentricity, we deduce a scaling function which facilitates content in the far periphery to be perceived as efficiently as in the central vision. AR overlays additional information on the real environment. This is useful in a number of fields, including surgery, where time-critical information is key. We present our medical AR system that visualizes the occluded catheter in the external ventricular drainage (EVD) procedure. We develop an accurate and efficient catheter tracking method that requires minimal changes to the existing medical equipment. The AR display projects a virtual image of the catheter overlaid on the occluded real catheter to depict its real-time position. Our system can make the risky EVD procedure much safer. Existing VR and AR displays support a limited number of focal distances, leading to vergence-accommodation conflict. Holographic displays can address this issue. In this dissertation, we explore the design and development of nanophotonic phased array (NPA) as a special class of holographic displays. NPAs have the advantage of being compact and support very high refresh rates. However, the use of the thermo-optic effect for phase modulation renders them susceptible to the thermal proximity effect. We study how the proximity effect impacts the images formed on NPAs. We then propose several novel algorithms to compensate for the thermal proximity effect on NPAs and compare their effectiveness and computational efficiency. Computer-generated holography (CGH) has traditionally focused on 2D images and 3D images in the form of meshes and point clouds. However, volumetric data can also benefit from CGH. One of the challenges in the use of volumetric data sources in CGH is the computational complexity needed to calculate the holograms of volumetric data. We propose a new method that achieves a significant speedup compared to existing holographic volume rendering methods.Item An Exploratory Study of Teachers' Perceptions of Administrative Support Influencing Retention in Title I Schools(2020) King, Brian Stephen; McLaughlin, Margaret J; Education Policy, and Leadership; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Title I schools, those with high percentages of students qualifying for Free and Reduced Meals (FARMS), face many challenges in serving their students. Among the most significant challenges these schools face is the likelihood they will be staffed by larger numbers of inexperienced teachers and inexperienced administrators than non-Title I schools (Cardichon et al., 2020; Carver-Thomas & Darling-Hammond, 2017; Machtinger, 2007). This study focused on the teacher experience level equity gap, or TELEG, between Title I and non-Title I schools in Soto County, a school system in a mid-Atlantic state. The researcher created the term TELEG to specify the equity gap being studied, namely, a teacher experience level equity gap. TELEG is calculated by comparing the percentage of inexperienced teachers at a school or group of schools to another school or group of schools. Teacher experience gaps impact student outcomes, district finances, and school culture. TELEG are often compounded by low teacher retention rates in Title I schools. Research indicates that a perceived lack of administrative support is the most predictive factor in teacher retention decisions (Ingersoll, 2011; Darling-Hammond, 2017; Boyd et al., 2011; Burkhauser, 2016; Player, 2012; Thibodeaux, 2015; Pogodzinski, 2012; Ladd, 2011). The qualitative study aimed to investigate inexperienced and experienced teachers' preferences regarding specific support provided by school-based administrators. The study sought to inform a change initiative that could test the theory that improving school-based administrative support for inexperienced teachers at Title I schools could improve those teachers' perceptions of support. The intended outcome is to decrease TELEG in Soto County by improving the retention of inexperienced teachers at Title I schools. Data was collected using focus groups and individual interviews. Analysis of the data sought to answer the study's two research questions: (1) how do inexperienced and experienced teachers describe desired and non-desired administrative support at their Title I school and (2) in what ways, if at all, do inexperienced teachers consider school-based administrator support in their decisions to remain teaching at their Title I school? The study found that inexperienced and experienced teachers desire support that is individualized and provides access to school-based administrators. The study also found that inexperienced teachers consider school-based administrator support in retention decisions to a lesser degree than experienced teachers.Item DWELLING: A PERSPECTIVE OF THE IN-BETWEEN(2019) Carlson, Stacey; Keefe, Maura; Dance; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Today’s contemporary circus is marked by a merging of embodied practices, including dance, puppetry and clowning. Apart from etymological play on meaning and the corporeal; the mixing, meddling, and swirling of genres not only offers the artist a new way to express sensory experiences, but also engages the artist and the art into a new interdependent relationship with an interactive audience. This research explores how these traditional and contemporary art forms are being interpreted, understood and contextualized. Through a tacit use of phenomenology, the study contributes to a better understanding of the location of embodied practice in dance research and it establishes the interconnectedness between tradition and modernity; past, present, and future; and the exploration of the in-between. Dwelling was an interdisciplinary work performed October 12 and 14, 2018 in the Kogod Theater at the Clarice Performing Arts Center in partial fulfillment of the Master in Fine Arts degree from the University of Maryland, College Park’s School of Theater, Dance, and Performance Studies.Item Computational Foundations for Safe and Efficient Human-Robot Collaboration in Assembly Cells(2016) Morato, Carlos W; Gupta, Satyandra K; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Human and robots have complementary strengths in performing assembly operations. Humans are very good at perception tasks in unstructured environments. They are able to recognize and locate a part from a box of miscellaneous parts. They are also very good at complex manipulation in tight spaces. The sensory characteristics of the humans, motor abilities, knowledge and skills give the humans the ability to react to unexpected situations and resolve problems quickly. In contrast, robots are very good at pick and place operations and highly repeatable in placement tasks. Robots can perform tasks at high speeds and still maintain precision in their operations. Robots can also operate for long periods of times. Robots are also very good at applying high forces and torques. Typically, robots are used in mass production. Small batch and custom production operations predominantly use manual labor. The high labor cost is making it difficult for small and medium manufacturers to remain cost competitive in high wage markets. These manufactures are mainly involved in small batch and custom production. They need to find a way to reduce the labor cost in assembly operations. Purely robotic cells will not be able to provide them the necessary flexibility. Creating hybrid cells where humans and robots can collaborate in close physical proximities is a potential solution. The underlying idea behind such cells is to decompose assembly operations into tasks such that humans and robots can collaborate by performing sub-tasks that are suitable for them. Realizing hybrid cells that enable effective human and robot collaboration is challenging. This dissertation addresses the following three computational issues involved in developing and utilizing hybrid assembly cells: - We should be able to automatically generate plans to operate hybrid assembly cells to ensure efficient cell operation. This requires generating feasible assembly sequences and instructions for robots and human operators, respectively. Automated planning poses the following two challenges. First, generating operation plans for complex assemblies is challenging. The complexity can come due to the combinatorial explosion caused by the size of the assembly or the complex paths needed to perform the assembly. Second, generating feasible plans requires accounting for robot and human motion constraints. The first objective of the dissertation is to develop the underlying computational foundations for automatically generating plans for the operation of hybrid cells. It addresses both assembly complexity and motion constraints issues. - The collaboration between humans and robots in the assembly cell will only be practical if human safety can be ensured during the assembly tasks that require collaboration between humans and robots. The second objective of the dissertation is to evaluate different options for real-time monitoring of the state of human operator with respect to the robot and develop strategies for taking appropriate measures to ensure human safety when the planned move by the robot may compromise the safety of the human operator. In order to be competitive in the market, the developed solution will have to include considerations about cost without significantly compromising quality. - In the envisioned hybrid cell, we will be relying on human operators to bring the part into the cell. If the human operator makes an error in selecting the part or fails to place it correctly, the robot will be unable to correctly perform the task assigned to it. If the error goes undetected, it can lead to a defective product and inefficiencies in the cell operation. The reason for human error can be either confusion due to poor quality instructions or human operator not paying adequate attention to the instructions. In order to ensure smooth and error-free operation of the cell, we will need to monitor the state of the assembly operations in the cell. The third objective of the dissertation is to identify and track parts in the cell and automatically generate instructions for taking corrective actions if a human operator deviates from the selected plan. Potential corrective actions may involve re-planning if it is possible to continue assembly from the current state. Corrective actions may also involve issuing warning and generating instructions to undo the current task.Item Bio-Inspired Small Field Perception for Navigation and Localization of MAV's in Cluttered Environments(2015) Escobar-Alvarez, Hector Domingo; Humbert, Sean J; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Insects are capable of agile pursuit of small targets while flying in complex cluttered environments. Additionally, insects are able to discern a moving background from smaller targets by combining their lightweight and fast vision system with efficient algorithms occurring in their neurons. On the other hand, engineering systems lack such capabilities since they either require large sensors, complex computations, or both. Bio-inspired small-field perception mechanisms have the potential to enhance the navigation of small unmanned aircraft systems in cluttered unknown environments. In this dissertation, we propose and investigate three methods to extract information about small-field objects from optic flow. The first method, \textit{flow of flow}, is analogous to processes taking place at the medulla level of the fruit-fly visuomotor system. The two other methods proposed are engineering approaches analogous to the figure-detection sensitive neurons at the lobula. All three methods employed demonstrated effective small-field information extraction from optic flow. The methods extract relative distance and azimuth location to the obstacles from an optic flow model. This optic flow model is based on parameterization of an environment containing small and wide-field obstacles. The three methodologies extract the high spatial frequency content of the optic flow by means of an elementary motion detector, Fourier series, and wavelet transforms, respectively. This extracted signal will contain the information about the small-field obstacles. The three methods were implemented on-board both a ground vehicle and an aerial vehicle to demonstrate and validate obstacle avoidance navigation in cluttered environments. Lastly, a localization framework based on wide field integration of nearness information (inverse of depth) is used for estimating vehicle navigation states in an unknown environment. Simulation of the localization framework demonstrates the ability to navigate to a target position using only nearness information.Item Architecture and the Senses: A Sensory Musing Park(2013) Stein, Sarah Noelle; Rockcastle, Garth; Architecture; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis studies the relationship of architecture and the senses. The first part of the document explores sensory characteristics and how they work. It defines their importance in allowing humans to navigate complex environments. The second part of the thesis looks directly at environmental stimuli. It seeks to qualify and associate physical variables with particular sensory responses. The goal of the research is to create a set of standards by which architecture can design "for the senses". The design project will put to test the principles organized from research through a series of architectural installations that harness both natural and man-made stimuli. The methodology with which stimuli are engaged will highlight time, place, and the awareness of being. Each installation is part of a greater constellation that can be sequenced in a variety of ways, experienced uniquely each time, and even added to by visitors and artists.Item Relative Salience of Envelope and Fine Structure Cues in Zebra Finch Song(2010) Vernaleo, Beth A.; Dooling, Robert J.; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation examines the perceptual salience of several acoustic cues in zebra finch song. Birdsong has long served as an animal model of speech development. Both are learned during a sensitive period, and require auditory feedback for learning and maintenance. Zebra finch song is commonly studied due to its stereotyped nature. Song syllables are complex, containing multiple cues that are modulated over millisecond time scales. Using psychoacoustic methods, male zebra finches were tested on discrimination of changes to their own and conspecific songs. Females and budgerigars were also tested, since they have auditory experience with song, but do not sing. Three types of synthetic songs were created to determine which acoustic cues in song were most salient to birds. Same-seed noise songs were made of syllable envelopes filled with the same piece of random Gaussian noise. This removed spectral structure but kept song envelope cues intact. Random noise songs were made of each syllable envelope filled with a unique piece of noise. This provided more complex fine structure to the same song envelope. Lastly, Schroeder songs were made of Schroeder harmonic waveforms with the same duration as song syllables. In Schroeder waveforms, spectrum and envelope are constant, but phase changes occur across frequencies. Two types of song changes were tested: single interval duration doublings and single syllable reversals. All birds were much more sensitive to syllable changes than to interval changes. For natural song, there was a duration effect on performance for male zebra finches only. Performance on syllable reversals shorter than 100 milliseconds was positively correlated with syllable duration. In Schroeder song, where only fine temporal structure changes with reversal, all three groups showed a duration effect. Thus, females and budgerigars may focus less on fine structure in natural song than males. In the absence of song spectral structure, birds relied on syllable envelope cues for reversal discrimination. Thus, removal of a single cue from song did not greatly affect reversal discrimination. However, birds performed best when all cues were present. This is reminiscent of human speech, in which multiple redundant cues are used for speech recognition.Item The structure and perception of budgerigar (Melopsittacus undulatus) warble songs(2009) Tu, Hsiao-Wei; Dooling, Robert J; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The warble song of male budgerigars (Melopsittacus undulatus) is an extraordinarily complex, multi-syllabic, learned vocalization that is produced continuously in streams lasting from a few seconds to a few minutes without obvious repetition of particular patterns. As a follow-up of the warble analysis of Farabaugh et al. (1992), an automatic categorization program based on neural networks was developed and used to efficiently and reliably classify more than 25,000 warble elements from 4 budgerigars. The relative proportion of the resultant seven basic acoustic groups and one compound group is similar across individuals. Budgerigars showed higher discriminability of warble elements drawn from different acoustic categories and lower discriminability of warble elements drawn from the same category psychophysically, suggesting that they form seven perceptual categories corresponding to those established acoustically. Budgerigars also perceive individual voice characteristics in addition to the acoustic measures delineating categories. Acoustic analyses of long sequences of natural warble revealed that the elements were not randomly arranged and that warble has at least a 5th-order Markovian structure. Perceptual experiments provided convergent evidence that budgerigars are able to master a novel sequence between 4 and 7 elements in length. Through gradual training with chunking (about 5 elements), birds are able to master sequences up to 50 elements. The ability of budgerigars to detect inserted targets taken in a long, running background of natural warble sequences appears to be species-specific and related to the acoustic structure of warble sounds.Item Where Colors Blend Into Sounds(2009) Kassabova, Tzveta; Rosen, Meriam; Dance; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Tzveta Kassabova creates an interactive environment for the audience, with dancers acting as guides through experiences of taste, touch and other sensations. The work plays with perceptions and shifting realities as it incorporates different approaches to scale and proximity. Corridors, entryways, and rooms are strung together, leading the audience into a maze of unexpected situations that are designed to evoke sensory memories and associations.