Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
Displaying 1 - 10 of 89
Description
When surgical resection becomes necessary to alleviate a patient's epileptiform activity, that patient is monitored by video synchronized with electrocorticography (ECoG) to determine the type and location of seizure focus. This provides a unique opportunity for researchers to gather neurophysiological data with high temporal and spatial resolution; these data are assessed prior to surgical resection to ensure the preservation of the patient's quality of life, e.g. avoid the removal of brain tissue required for speech processing. Currently considered the "gold standard" for the mapping of cortex, electrical cortical stimulation (ECS) involves the systematic activation of pairs of electrodes to localize functionally specific brain regions. This method has distinct limitations, which often includes pain experienced by the patient. Even in the best cases, the technique suffers from subjective assessments on the parts of both patients and physicians, and high inter- and intra-observer variability. Recent advances have been made as researchers have reported the localization of language areas through several signal processing methodologies, all necessitating patient participation in a controlled experiment. The development of a quantification tool to localize speech areas in which a patient is engaged in an unconstrained interpersonal conversation would eliminate the dependence of biased patient and reviewer input, as well as unnecessary discomfort to the patient. Post-hoc ECoG data were gathered from five patients with intractable epilepsy while each was engaged in a conversation with family members or clinicians. After the data were separated into different speech conditions, the power of each was compared to baseline to determine statistically significant activated electrodes. The results of several analytical methods are presented here. The algorithms did not yield language-specific areas exclusively, as broad activation of statistically significant electrodes was apparent across cortical areas. For one patient, 15 adjacent contacts along superior temporal gyrus (STG) and posterior part of the temporal lobe were determined language-significant through a controlled experiment. The task involved a patient lying in bed listening to repeated words, and yielded statistically significant activations that aligned with those of clinical evaluation. The results of this study do not support the hypothesis that unconstrained conversation may be used to localize areas required for receptive and productive speech, yet suggests a simple listening task may be an adequate alternative to direct cortical stimulation.
ContributorsLingo VanGilder, Jennapher (Author) / Helms Tillery, Stephen I (Thesis advisor) / Wahnoun, Remy (Thesis advisor) / Buneo, Christopher (Committee member) / Arizona State University (Publisher)
Created2013
Description
Intracortical microstimulation (ICMS) within somatosensory cortex can produce artificial sensations including touch, pressure, and vibration. There is significant interest in using ICMS to provide sensory feedback for a prosthetic limb. In such a system, information recorded from sensors on the prosthetic would be translated into electrical stimulation and delivered directly to the brain, providing feedback about features of objects in contact with the prosthetic. To achieve this goal, multiple simultaneous streams of information will need to be encoded by ICMS in a manner that produces robust, reliable, and discriminable sensations. The first segment of this work focuses on the discriminability of sensations elicited by ICMS within somatosensory cortex. Stimulation on multiple single electrodes and near-simultaneous stimulation across multiple electrodes, driven by a multimodal tactile sensor, were both used in these experiments. A SynTouch BioTac sensor was moved across a flat surface in several directions, and a subset of the sensor's electrode impedance channels were used to drive multichannel ICMS in the somatosensory cortex of a non-human primate. The animal performed a behavioral task during this stimulation to indicate the discriminability of sensations evoked by the electrical stimulation. The animal's responses to ICMS were somewhat inconsistent across experimental sessions but indicated that discriminable sensations were evoked by both single and multichannel ICMS. The factors that affect the discriminability of stimulation-induced sensations are not well understood, in part because the relationship between ICMS and the neural activity it induces is poorly defined. The second component of this work was to develop computational models that describe the populations of neurons likely to be activated by ICMS. Models of several neurons were constructed, and their responses to ICMS were calculated. A three-dimensional cortical model was constructed using these cell models and used to identify the populations of neurons likely to be recruited by ICMS. Stimulation activated neurons in a sparse and discontinuous fashion; additionally, the type, number, and location of neurons likely to be activated by stimulation varied with electrode depth.
ContributorsOverstreet, Cynthia K (Author) / Helms Tillery, Stephen I (Thesis advisor) / Santos, Veronica (Committee member) / Buneo, Christopher (Committee member) / Otto, Kevin (Committee member) / Santello, Marco (Committee member) / Arizona State University (Publisher)
Created2013
Description
This dissertation explores the role of smart home service provisions (SHSP) as motivational agents supporting goal attainment and human flourishing. Evoking human flourishing as a lens for interaction encapsulates issues of wellbeing, adaptation and problem solving within the context of social interaction. To investigate this line of research a new, motivation-sensitive approach to design was implemented. This approach combined psychometric analysis from motivational psychology's Personal Project Analysis (PPA) and Place Attachment theory's Sense of Place (SoP) analysis to produce project-centered motivational models for environmental congruence. Regression analysis of surveys collected from 150 (n = 150) young adults about their homes revealed PPA motivational dimensions had significant main affects on all three SoP factors. Model one indicated PPA dimensions Fearful and Value Congruency predicted the SoP factor Place Attachment (p = 0.012). Model two indicated the PPA factor Positive Affect and PPA dimensions Value Congruency, Self Identity and Autonomy predicted Place Identity (p = .0003). Model three indicated PPA dimensions Difficulty and Likelihood of Success predicted the SoP factor Place Dependency. The relationships between motivational PPA dimensions and SoP demonstrated in these models informed creation of a set of motivational design heuristics. These heuristics guided 20 participants (n = 20) through co-design of paper prototypes of SHSPs supporting goal attainment and human flourishing. Normative analysis of these paper prototypes fashioned a design framework consisting of the use cases "make with me", "keep me on task" and "improve myself"; the four design principles "time and timing", "guidance and accountability", "project ambiguity" and "positivity mechanisms"; and the seven interaction models "structuring time", "prompt user", "gather resources", "consume content", "create content", "restrict and/or restore access to content" and "share content". This design framework described and evaluated three technology probes installed in the homes of three participants (n = 3) for field-testing over the course of one week. A priori and post priori samples of psychometric measures were inconclusive in determining if SHSP motivated goal attainment or increased environmental congruency between young adults and their homes.
ContributorsBrotman, Ryan Scott (Author) / Burleson, Winsow (Thesis advisor) / Heywood, William (Committee member) / Forlizzi, Jodi (Committee member) / Arizona State University (Publisher)
Created2013
Description
Humans' ability to perform fine object and tool manipulation is a defining feature of their sensorimotor repertoire. How the central nervous system builds and maintains internal representations of such skilled hand-object interactions has attracted significant attention over the past three decades. Nevertheless, two major gaps exist: a) how digit positions and forces are coordinated during natural manipulation tasks, and b) what mechanisms underlie the formation and retention of internal representations of dexterous manipulation. This dissertation addresses these two questions through five experiments that are based on novel grip devices and experimental protocols. It was found that high-level representation of manipulation tasks can be learned in an effector-independent fashion. Specifically, when challenged by trial-to-trial variability in finger positions or using digits that were not previously engaged in learning the task, subjects could adjust finger forces to compensate for this variability, thus leading to consistent task performance. The results from a follow-up experiment conducted in a virtual reality environment indicate that haptic feedback is sufficient to implement the above coordination between digit position and forces. However, it was also found that the generalizability of a learned manipulation is limited across tasks. Specifically, when subjects learned to manipulate the same object across different contexts that require different motor output, interference was found at the time of switching contexts. Data from additional studies provide evidence for parallel learning processes, which are characterized by different rates of decay and learning. These experiments have provided important insight into the neural mechanisms underlying learning and control of object manipulation. The present findings have potential biomedical applications including brain-machine interfaces, rehabilitation of hand function, and prosthetics.
ContributorsFu, Qiushi (Author) / Santello, Marco (Thesis advisor) / Helms Tillery, Stephen (Committee member) / Buneo, Christopher (Committee member) / Santos, Veronica (Committee member) / Artemiadis, Panagiotis (Committee member) / Arizona State University (Publisher)
Created2013
Description
Research has shown that the ability to smell is the most direct sense an individual can experience. With every breath a person takes, the brain recognizes thousands of molecules and makes connections with our memories to determine their composition. With the amount of research looking into how and why we smell, researchers still have little understanding of how the nose and brain process an aroma, and how emotional and physical behavior is impacted. This research focused on the affects smell has on a caregiver in a simulated Emergency Department setting located in the SimET of Banner Good Samaritan Medical Center in Phoenix, Arizona. The study asked each participant to care for a programmed mannequin, or "patient", while performing simple computer-based tasks, including memory and recall, multi-tasking, and mood-mapping to gauge physical and mental performance. Three different aromatic environments were then introduced through diffusion and indirect inhalation near the participants' task space: 1) a control (no smell), 2) an odor (simulated dirty feet), and 3) an aroma (one of four true essential oils plus a current odor-eliminating compound used in many U.S. Emergency Departments). This study was meant to produce a stressful environment by leading the caregiver to stay in constant movement throughout the study through timed tasks, uncooperative equipment, and a needy "patient". The goal of this research was to determine if smells, and of what form of pleasantness and repulsiveness, can have an effect on the physical and mental performance of emergency caregivers. Findings from this study indicated that the "odor eliminating" method currently used in typical Emergency Departments, coffee grounds, is more problematic than helpful, and the introduction of true essential oils may not only reduce stress, but increase efficiency and, in turn, job satisfaction.
ContributorsClark, Carina M (Author) / Bernardi, Jose (Thesis advisor) / Heywood, William (Committee member) / Watts, Richard (Committee member) / Rosso, Rachel (Committee member) / Arizona State University (Publisher)
Created2013
Description
A growing body of research shows that characteristics of the built environment in healthcare facilities impact patients' well-being. Research findings suggest that patients form judgments of perceived quality care based on environmental characteristics. Patient outcomes and ratings of quality of care are linked to the environments' ability to reduce patient stress as well as influence perceptions of quality of care. Historically, this research has been focused in the hospital environment. The United States healthcare system heavily relies on hospitals to treat (rather than prevent) illness, leading to a high per capita healthcare expenditure. Currently, this healthcare system is shifting to rely heavily on ambulatory care settings and primary care providers to detect, prevent, and manage expensive medical conditions. The highest rates of preventable disease and the lowest rates of primary care usage are found in the young adult population (ages 18 to 24). More than any other patient population, this segment rates their satisfaction with healthcare significantly low. For this population education, early detection, and monitoring will be key for a primary care focused model to have the greatest impact on care and long-term savings. Strong patient-physician connections ensure the success of a primary care focused model. The physical environment has the opportunity to provide a message consistent with a physician's practice values and goals. Environmental cues in the waiting area have the potential to relay these messages to the patient prior to physician contact. Through an understanding and optimization of these cues patient perception of quality of care may be increased, thus improving the patient-physician relationship. This study provides insight on how to optimize environmental impact on the healthcare experience. This descriptive exploratory study utilized a non-verbal self-report instrument to collect demographic information and measure participant's responses to two panoramic photos of primary care provider waiting areas. Respondents were asked to identify physical elements in the photos that contributed to their perceptions of the quality of care to be expected. The sample population consisted of 33, 18 to 24 year-olds leaving a total of 234 emotional markers and comments. Qualitative and quantitative revealed three key themes of appeal, comfort, and regard. Physical elements, in the photos, related to the themes include: General areas that were important to the respondents were the seating and reception areas, as well as the overall appearance of the waiting area. Key elements identified to be significant characteristics influencing perceptions of quality of care are presented in this study.
ContributorsBadura, Kerri (Author) / Lamb, Gerri (Thesis advisor) / Heywood, William (Committee member) / Wolf, Peter (Committee member) / Arizona State University (Publisher)
Created2012
Description
Advances in implantable MEMS technology has made possible adaptive micro-robotic implants that can track and record from single neurons in the brain. Development of autonomous neural interfaces opens up exciting possibilities of micro-robots performing standard electrophysiological techniques that would previously take researchers several hundred hours to train and achieve the desired skill level. It would result in more reliable and adaptive neural interfaces that could record optimal neural activity 24/7 with high fidelity signals, high yield and increased throughput. The main contribution here is validating adaptive strategies to overcome challenges in autonomous navigation of microelectrodes inside the brain. The following issues pose significant challenges as brain tissue is both functionally and structurally dynamic: a) time varying mechanical properties of the brain tissue-microelectrode interface due to the hyperelastic, viscoelastic nature of brain tissue b) non-stationarities in the neural signal caused by mechanical and physiological events in the interface and c) the lack of visual feedback of microelectrode position in brain tissue. A closed loop control algorithm is proposed here for autonomous navigation of microelectrodes in brain tissue while optimizing the signal-to-noise ratio of multi-unit neural recordings. The algorithm incorporates a quantitative understanding of constitutive mechanical properties of soft viscoelastic tissue like the brain and is guided by models that predict stresses developed in brain tissue during movement of the microelectrode. An optimal movement strategy is developed that achieves precise positioning of microelectrodes in the brain by minimizing the stresses developed in the surrounding tissue during navigation and maximizing the speed of movement. Results of testing the closed-loop control paradigm in short-term rodent experiments validated that it was possible to achieve a consistently high quality SNR throughout the duration of the experiment. At the systems level, new generation of MEMS actuators for movable microelectrode array are characterized and the MEMS device operation parameters are optimized for improved performance and reliability. Further, recommendations for packaging to minimize the form factor of the implant; design of device mounting and implantation techniques of MEMS microelectrode array to enhance the longevity of the implant are also included in a top-down approach to achieve a reliable brain interface.
ContributorsAnand, Sindhu (Author) / Muthuswamy, Jitendran (Thesis advisor) / Tillery, Stephen H (Committee member) / Buneo, Christopher (Committee member) / Abbas, James (Committee member) / Tsakalis, Konstantinos (Committee member) / Arizona State University (Publisher)
Created2013
Description
Generally speaking, many programs of interior design have had a gender imbalance in the student population. As a case in point, the interior design program at Arizona State University (ASU) is at present ninety percent female. While other design programs such as architecture or industrial design have achieved gender balance, interior design has not. This research explores the reasons why male students are not enrolling in the interior design program at ASU and to what degree gender influences the selection of a major. The objectives of this research are to determine: 1) what role gender plays in the selection of interior design as a choice of a major at ASU; 2) why might male students be hesitant to join the interior design program; 3) why female students are attracted to interior design; 4) if there are gender differences in design approach; and 5) if curricular differences between interior architecture and interior design impact the gender imbalance. A mixed method approach is used in order to answer the research questions including: a literature review, a visual ethnography, and interviews of interior design students and faculty members at ASU. The results reveal that gender might have an effect on students' decision to join the interior design program. For a male student, people questioned his sexuality because they assumed he would have to be of a certain sexual orientation to study interior design. According to a male faculty member upon visiting a middle school on career day, young boys would be interested in the projects displayed at the interior design booth until they figured out what it was. Even at a young age, the boys seemed to know that interior design was a female's domain. A participant stated that women seemed to be less critical of the men's projects and were more critical of each other. A male respondent stated that on the occasion there were no men in the class the studio culture changed. Another stated that interior design students did not take feedback as well as others and need to be affirmed more often. Gender socialization, the history of interior design as a feminine career, and the title "interior design" itself are all possible factors that could deter male students from joining the program. The insights acquired from this research will provide students and faculty members from The Design School and beyond a better understanding of gender socialization and what the interior design program has to offer.
ContributorsRuff, Charlene (Author) / Giard, Jacques (Thesis advisor) / Heywood, William (Committee member) / Margolis, Eric (Committee member) / Arizona State University (Publisher)
Created2014
Description
The study of lighting design has important implications for consumer behavior and is an important aspect of consideration for the retail industry. In today's global economy consumers can come from a number of cultural backgrounds. It is important to understand various cultures' perceptions of lighting design in order for retailers to better understand how to use lighting as a benefit to provide consumers with a desirable shopping experience. This thesis provides insight into the effects of ambient lighting on product perception among Americans and Middle Easterners. Both cultural groups' possess significant purchasing power in the worldwide market place. This research will allow marketers, designers and consumers a better understanding of how culture may play a role in consumer perceptions and behavior Results of this study are based on data gathered from 164 surveys from individuals of American and Middle Eastern heritage. Follow up interviews were also conducted to examine the nuances of product perception and potential differences across cultures. This study, using qualitative and quantitative methods, was executed using a Sequential Explanatory Strategy. Survey data were analyzed to uncover significant correlations and relationships using measures of descriptive analysis, analysis of variance (ANOVA), and regression analysis. Interviews were analyzed using theme-based coding and reported in narrative form. The results suggest that lighting does in fact have an impact on product perception, however despite minor differences, this perception does not vary much between individuals from American and Middle Eastern cultures. It was found that lighting could affect price and quality perception with reference to store-image and store atmospherics. Additionally, lighting has a higher impact on subjective impressions of product (such as Freshness, Pleasantness, and Attractiveness), more than Price and Quality perceptions. This study suggests that particular lighting characteristics could be responsible for differences in product perception between these two cultures. This is important to note for lighting designers and marketers to create retail atmospheres that are preferable to both cultures.
ContributorsAlsharhan, Dalal Anwar (Author) / Kroelinger, Michael D. (Thesis advisor) / Eaton, John (Committee member) / Heywood, William (Committee member) / Arizona State University (Publisher)
Created2013
Description
The development of literacy abilities in young children has been a major concern for authorities and teachers in the USA for the last two decades. Significant effort has been devoted to ensure that preschool settings allow and motivate children to engage in literacy activities before entering kindergarten. Research has found that a rich classroom environment in preschool settings enables teachers to encourage literacy interest in children at a young age. While a large amount of research has concentrated in testing the effect of prescriptive modifications in the classroom environment, few have focused on studying the design process and tools that teachers follow to design their classrooms. Public policy and research studies in the United States, mention the design of the classroom environment among teacher's responsibilities, but they do not include practical or methodological guides for them to use. The purpose of this research was to study the design process and tools that teachers use to design literacy rich classrooms in preschool settings. A case study was conducted at the ASU Mary Lou Fulton Teachers College Preschool at Arizona State University. This setting provides a unique opportunity for an exploratory study of this nature because it is a private child development laboratory with a flexible curriculum. Participant observation sessions and in depth semi-structured interviews were conducted to explore the design process used and experienced by the teachers. Findings revealed an iterative and cyclic design process that is repeated over time adjusting to the influence of numerous factors. Results also suggest that teacher's knowledge and beliefs highly influence the organization of their classrooms. Considering these factors as a standpoint allows for further exploration to determine a design process suitable for teachers when designing their learning environments. The use of a structured yet flexible design process, can be a potential tool for educators to design their classrooms, collaborate, document and transmit their knowledge. Although the findings correspond to a specific site studied, the implications are wide reaching as problems and opportunities expressed by the staff are common to other educational settings with similar characteristics.
ContributorsCortes, Catalina (Author) / Patel, Mookesh (Thesis advisor) / Heywood, William (Committee member) / Christie, James (Committee member) / Arizona State University (Publisher)
Created2013