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- Creators: Dean, W.P. Carey School of Business
- Resource Type: Text
- Status: Published
Description
Approximately 1.7 million people in the United States are living with limb loss and are in need of more sophisticated devices that better mimic human function. In the Human Machine Integration Laboratory, a powered, transtibial prosthetic ankle was designed and build that allows a person to regain ankle function with improved ankle kinematics and kinetics. The ankle allows a person to walk normally and up and down stairs, but volitional control is still an issue. This research tackled the problem of giving the user more control over the prosthetic ankle using a force/torque circuit. When the user presses against a force/torque sensor located inside the socket the prosthetic foot plantar flexes or moves downward. This will help the user add additional push-off force when walking up slopes or stairs. It also gives the user a sense of control over the device.
ContributorsFronczyk, Adam (Author) / Sugar, Thomas G. (Thesis advisor) / Helms-Tillery, Stephen (Thesis advisor) / Santello, Marco (Committee member) / Arizona State University (Publisher)
Created2012
Description
Understanding where our bodies are in space is imperative for motor control, particularly for actions such as goal-directed reaching. Multisensory integration is crucial for reducing uncertainty in arm position estimates. This dissertation examines time and frequency-domain correlates of visual-proprioceptive integration during an arm-position maintenance task. Neural recordings were obtained from two different cortical areas as non-human primates performed a center-out reaching task in a virtual reality environment. Following a reach, animals maintained the end-point position of their arm under unimodal (proprioception only) and bimodal (proprioception and vision) conditions. In both areas, time domain and multi-taper spectral analysis methods were used to quantify changes in the spiking, local field potential (LFP), and spike-field coherence during arm-position maintenance.
In both areas, individual neurons were classified based on the spectrum of their spiking patterns. A large proportion of cells in the SPL that exhibited sensory condition-specific oscillatory spiking in the beta (13-30Hz) frequency band. Cells in the IPL typically had a more diverse mix of oscillatory and refractory spiking patterns during the task in response to changing sensory condition. Contrary to the assumptions made in many modelling studies, none of the cells exhibited Poisson-spiking statistics in SPL or IPL.
Evoked LFPs in both areas exhibited greater effects of target location than visual condition, though the evoked responses in the preferred reach direction were generally suppressed in the bimodal condition relative to the unimodal condition. Significant effects of target location on evoked responses were observed during the movement period of the task well.
In the frequency domain, LFP power in both cortical areas was enhanced in the beta band during the position estimation epoch of the task, indicating that LFP beta oscillations may be important for maintaining the ongoing state. This was particularly evident at the population level, with clear increase in alpha and beta power. Differences in spectral power between conditions also became apparent at the population level, with power during bimodal trials being suppressed relative to unimodal. The spike-field coherence showed confounding results in both the SPL and IPL, with no clear correlation between incidence of beta oscillations and significant beta coherence.
In both areas, individual neurons were classified based on the spectrum of their spiking patterns. A large proportion of cells in the SPL that exhibited sensory condition-specific oscillatory spiking in the beta (13-30Hz) frequency band. Cells in the IPL typically had a more diverse mix of oscillatory and refractory spiking patterns during the task in response to changing sensory condition. Contrary to the assumptions made in many modelling studies, none of the cells exhibited Poisson-spiking statistics in SPL or IPL.
Evoked LFPs in both areas exhibited greater effects of target location than visual condition, though the evoked responses in the preferred reach direction were generally suppressed in the bimodal condition relative to the unimodal condition. Significant effects of target location on evoked responses were observed during the movement period of the task well.
In the frequency domain, LFP power in both cortical areas was enhanced in the beta band during the position estimation epoch of the task, indicating that LFP beta oscillations may be important for maintaining the ongoing state. This was particularly evident at the population level, with clear increase in alpha and beta power. Differences in spectral power between conditions also became apparent at the population level, with power during bimodal trials being suppressed relative to unimodal. The spike-field coherence showed confounding results in both the SPL and IPL, with no clear correlation between incidence of beta oscillations and significant beta coherence.
ContributorsVanGilder, Paul (Author) / Buneo, Christopher A (Thesis advisor) / Helms-Tillery, Stephen (Committee member) / Santello, Marco (Committee member) / Muthuswamy, Jit (Committee member) / Foldes, Stephen (Committee member) / Arizona State University (Publisher)
Created2017
Description
Growing understanding of the neural code and how to speak it has allowed for notable advancements in neural prosthetics. With commercially-available implantable systems with bi- directional neural communication on the horizon, there is an increasing imperative to develop high resolution interfaces that can survive the environment and be well tolerated by the nervous system under chronic use. The sensory encoding aspect optimally interfaces at a scale sufficient to evoke perception but focal in nature to maximize resolution and evoke more complex and nuanced sensations. Microelectrode arrays can maintain high spatial density, operating on the scale of cortical columns, and can be either penetrating or non-penetrating. The non-penetrating subset sits on the tissue surface without puncturing the parenchyma and is known to engender minimal tissue response and less damage than the penetrating counterpart, improving long term viability in vivo. Provided non-penetrating microelectrodes can consistently evoke perception and maintain a localized region of activation, non-penetrating micro-electrodes may provide an ideal platform for a high performing neural prosthesis; this dissertation explores their functional capacity.
The scale at which non-penetrating electrode arrays can interface with cortex is evaluated in the context of extracting useful information. Articulate movements were decoded from surface microelectrode electrodes, and additional spatial analysis revealed unique signal content despite dense electrode spacing. With a basis for data extraction established, the focus shifts towards the information encoding half of neural interfaces. Finite element modeling was used to compare tissue recruitment under surface stimulation across electrode scales. Results indicated charge density-based metrics provide a reasonable approximation for current levels required to evoke a visual sensation and showed tissue recruitment increases exponentially with electrode diameter. Micro-scale electrodes (0.1 – 0.3 mm diameter) could sufficiently activate layers II/III in a model tuned to striate cortex while maintaining focal radii of activated tissue.
In vivo testing proceeded in a nonhuman primate model. Stimulation consistently evoked visual percepts at safe current thresholds. Tracking perception thresholds across one year reflected stable values within minimal fluctuation. Modulating waveform parameters was found useful in reducing charge requirements to evoke perception. Pulse frequency and phase asymmetry were each used to reduce thresholds, improve charge efficiency, lower charge per phase – charge density metrics associated with tissue damage. No impairments to photic perception were observed during the course of the study, suggesting limited tissue damage from array implantation or electrically induced neurotoxicity. The subject consistently identified stimulation on closely spaced electrodes (2 mm center-to-center) as separate percepts, indicating sub-visual degree discrete resolution may be feasible with this platform. Although continued testing is necessary, preliminary results supports epicortical microelectrode arrays as a stable platform for interfacing with neural tissue and a viable option for bi-directional BCI applications.
The scale at which non-penetrating electrode arrays can interface with cortex is evaluated in the context of extracting useful information. Articulate movements were decoded from surface microelectrode electrodes, and additional spatial analysis revealed unique signal content despite dense electrode spacing. With a basis for data extraction established, the focus shifts towards the information encoding half of neural interfaces. Finite element modeling was used to compare tissue recruitment under surface stimulation across electrode scales. Results indicated charge density-based metrics provide a reasonable approximation for current levels required to evoke a visual sensation and showed tissue recruitment increases exponentially with electrode diameter. Micro-scale electrodes (0.1 – 0.3 mm diameter) could sufficiently activate layers II/III in a model tuned to striate cortex while maintaining focal radii of activated tissue.
In vivo testing proceeded in a nonhuman primate model. Stimulation consistently evoked visual percepts at safe current thresholds. Tracking perception thresholds across one year reflected stable values within minimal fluctuation. Modulating waveform parameters was found useful in reducing charge requirements to evoke perception. Pulse frequency and phase asymmetry were each used to reduce thresholds, improve charge efficiency, lower charge per phase – charge density metrics associated with tissue damage. No impairments to photic perception were observed during the course of the study, suggesting limited tissue damage from array implantation or electrically induced neurotoxicity. The subject consistently identified stimulation on closely spaced electrodes (2 mm center-to-center) as separate percepts, indicating sub-visual degree discrete resolution may be feasible with this platform. Although continued testing is necessary, preliminary results supports epicortical microelectrode arrays as a stable platform for interfacing with neural tissue and a viable option for bi-directional BCI applications.
ContributorsOswalt, Denise (Author) / Greger, Bradley (Thesis advisor) / Buneo, Christopher (Committee member) / Helms-Tillery, Stephen (Committee member) / Mirzadeh, Zaman (Committee member) / Papandreou-Suppappola, Antonia (Committee member) / Arizona State University (Publisher)
Created2018
Description
Proprioception is the sense of body position, movement, force, and effort. Loss of proprioception can affect planning and control of limb and body movements, negatively impacting activities of daily living and quality of life. Assessments employing planar robots have shown that proprioceptive sensitivity is directionally dependent within the horizontal plane however, few studies have looked at proprioceptive sensitivity in 3d space. In addition, the extent to which proprioceptive sensitivity is modifiable by factors such as exogenous neuromodulation is unclear. To investigate proprioceptive sensitivity in 3d we developed a novel experimental paradigm employing a 7-DoF robot arm, which enables reliable testing of arm proprioception along arbitrary paths in 3d space, including vertical motion which has previously been neglected. A participant’s right arm was coupled to a trough held by the robot that stabilized the wrist and forearm, allowing for changes in configuration only at the elbow and shoulder. Sensitivity to imposed displacements of the endpoint of the arm were evaluated using a “same/different” task, where participant’s hands were moved 1-4 cm from a previously visited reference position. A measure of sensitivity (d’) was compared across 6 movement directions and between 2 postures. For all directions, sensitivity increased monotonically as the distance from the reference location increased. Sensitivity was also shown to be anisotropic (directionally dependent) which has implications for our understanding of the planning and control of reaching movements in 3d space.
The effect of neuromodulation on proprioceptive sensitivity was assessed using transcutaneous electrical nerve stimulation (TENS), which has been shown to have beneficial effects on human cognitive and sensorimotor performance in other contexts. In this pilot study the effects of two frequencies (30hz and 300hz) and three electrode configurations were examined. No effect of electrode configuration was found, however sensitivity with 30hz stimulation was significantly lower than with 300hz stimulation (which was similar to sensitivity without stimulation). Although TENS was shown to modulate proprioceptive sensitivity, additional experiments are required to determine if TENS can produce enhancement rather than depression of sensitivity which would have positive implications for rehabilitation of proprioceptive deficits arising from stroke and other disorders.
The effect of neuromodulation on proprioceptive sensitivity was assessed using transcutaneous electrical nerve stimulation (TENS), which has been shown to have beneficial effects on human cognitive and sensorimotor performance in other contexts. In this pilot study the effects of two frequencies (30hz and 300hz) and three electrode configurations were examined. No effect of electrode configuration was found, however sensitivity with 30hz stimulation was significantly lower than with 300hz stimulation (which was similar to sensitivity without stimulation). Although TENS was shown to modulate proprioceptive sensitivity, additional experiments are required to determine if TENS can produce enhancement rather than depression of sensitivity which would have positive implications for rehabilitation of proprioceptive deficits arising from stroke and other disorders.
ContributorsKlein, Joshua (Author) / Buneo, Christopher (Thesis advisor) / Helms-Tillery, Stephen (Committee member) / Kleim, Jeffrey (Committee member) / Santello, Marco (Committee member) / Arizona State University (Publisher)
Created2018
Description
This project uses Kenneth Burke’s theory of dramatism and the pentad to analyze popular narrative films about human sex trafficking. It seeks to understand the relationship between a film’s dominant philosophy (as highlighted by utilizing Burke’s pentad), its inherently suggested solutions to trafficking, and the effect that the film has on viewers’ perception of trafficking. 20 narrative feature films about sex trafficking such as the 2008 film Taken were analyzed for this study. Three out of five of Burke’s philosophies were uncovered after analysis: idealism, mysticism, and materialism. Films that aligned with idealism were found to implicitly blame women for their own trafficking. Films that aligned with mysticism were found to rally audiences around violence and racism as opposed to women’s freedom. Films that aligned with materialism were found to be the most empathetic towards trafficked women. The conclusion of this paper is that films about sex trafficking have a high potential to be harmful to women who have exited trafficking. This paper asserts that the most valuable films about trafficking are those that are not simply based on a true story but are created by trafficking survivors themselves, such as the 2016 film Apartment 407.
ContributorsHamby, Hannah Mary (Co-author) / Raum, Brionna (Co-author) / Edson, Belle (Thesis director) / Zanin, Alaina (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Hugh Downs School of Human Communication (Contributor) / School of Film, Dance and Theatre (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
This document is a proposal for a research project, submitted as an Honors Thesis to Barrett, The Honors College at Arizona State University. The proposal summarizes previous findings and literature about women survivors of domestic violence who are suffering from post-traumatic stress disorder as well as outlining the design and measures of the study. At this time, the study has not been completed. However, it may be completed at a future time.
ContributorsKunst, Jessica (Author) / Hernandez Ruiz, Eugenia (Thesis director) / Belgrave, Melita (Committee member) / School of Music (Contributor) / Dean, W.P. Carey School of Business (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
While there are many characteristics that make up a woman, femininity is one that is difficult to define because it is a communication and expression practice defined by culture. This research explores historical accounts of femininity in the 1950s as seen through the exemplar of the white, middle-class "happy homemaker" or "happy housewife." The 1950s is important to study in light of changing gender and social dynamics due to the transition from World War II to a period of prosperity. By using primary sources from the 1950s and secondary historical analyses, this research takes the form of a sociological accounting of 1950s' femininity and the lessons that can be applied today. Four cultural forces led to homemakers having an unspoken identity crisis because they defined themselves in terms of relationship with others and struggled to uphold a certain level of femininity. The forces are: the feminine mystique, patriotism, cultural normalcy, and unnecessary choices. These forces caused women to have unhealthy home relationships in their marriages and motherhood while persistently doing acts to prove their self-worth, such as housework and consuming. It is important to not look back at the 1950s as an idyllic time without also considering the social and cultural practices that fostered a feminine conformity in women. Today, changes can be made to allow women to express femininity in modern ways by adapting to reality instead of to outdated values. For example, changes in maternity leave policies allow women to be mothers and still be in the workforce. Additionally, women should find fulfillment in themselves by establishing a strong personal identity and confidence in their womanhood before identifying through other people or through society.
ContributorsHeinauer, Richelle Diane (Author) / Brouwer, Daniel (Thesis director) / Haskin, Jennifer (Committee member) / Hugh Downs School of Human Communication (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
The Centers for Disease Control and Prevention in the United States announced that there has been roughly a 50% increase in the prevalence of food allergies among people between the years of 1997 - 2011. A food allergy can be described as a medical condition where being exposed to a certain food triggers a harmful immune response in the body, known as an allergic reaction. These reactions can range from mild to fatal, and they are caused mainly by the top 8 major food allergens: dairy, eggs, peanuts, tree nuts, wheat, soy, fish, and shellfish. Food allergies mainly plague children under the age of 3, as some of them will grow out of their allergy sensitivity over time, and most people develop their allergies at a young age, and not when they are older. The rise in prevalence is becoming a frightening problem around the world, and there are emerging theories that are attempting to ascribe a cause. There are three well-known hypotheses that will be discussed: the Hygiene Hypothesis, the Dual-Allergen Exposure Hypothesis, and the Vitamin-D Deficiency Hypothesis. Beyond that, this report proposes that a new hypothesis be studied, the Food Systems Hypothesis. This hypothesis theorizes that the cause of the rise of food allergies is actually caused by changes in the food itself and particularly the pesticides that are used to cultivate it.
ContributorsCromer, Kelly (Author) / Lee, Rebecca (Thesis director) / MacFadyen, Joshua (Committee member) / Sanford School of Social and Family Dynamics (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Fashion is individual in its expression. It is also universal. Fashion is a cumulation of different influences and different interpretations. We currently live in a climate divided by race, culture, gender, and so much more. It is so difficult to find common ground on a global platform. Something that stands alone is fashion. Fashion is influenced by so many aspects. Of these, aspects that I am interested in are culture and sustainability. When combined with culture, fashion can anchor and have a root to the generations that came before us. When combined with sustainability, we have an anchor to the planet that we share with everyone. The result of fashion is always the same, beautiful art. I want people to see the beauty not only in the art itself, but the differences and similarities that such art provides. We all come from the same world but have different ways of expressing that world. My goal is to show people that they need to acknowledge the differences but can choose to see the similarities of each culture. Additionally, I redesign garments that capture an emotion and a story. Making each piece individual yet serving a greater purpose sustainability wise. I envision the principle of sustainable fashion to be the basis of each piece of clothing. Therefore, for my creative project I am constructing five art pieces representing five cultures that has had a significant influence on my life and personal style. These cultures are those of UAE, Germany, Nepal, Mexico, and Spain. Each of these garments are made from recycled fabric and clothing donated by family and friends. My objective is to display sustainable fashion that has deep cultural influence. Every piece has a story and an emotion attached as well to create a connection with the clothing itself.
ContributorsKreiser, Samantha Miren (Author) / Chhetri, Nalini (Thesis director) / Ellis, Naomi (Committee member) / Dean, W.P. Carey School of Business (Contributor, Contributor) / Department of Economics (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Everyone has a story to tell. Marketing nowadays is less about what is being made and more about how it is being told. Integrate an exciting or interesting story with sports and that is the ultimate storytelling experience. Social media has completely changed the game for professional teams when it comes to how teams are telling their digital stories and engaging with fans. Entire social media teams exist in these organizations, which is something that did not exist not too long ago. The rise in fans experiencing and viewing social media platforms is altering how teams engage, connect, and communicate with fans.
When it comes to my story, I wanted to make sure I told one that was interesting, relevant and worthwhile. I felt lost for quite some time in regards to what direction I wanted to take with my thesis. After meeting with Dan Moriarty and Kevin Brilliant of the Chicago Bulls during an outreach trip with the Sports Business Association, I knew I wanted to gain more insight into how teams are telling their digital stories and connecting with their fans. I wanted to learn more about how teams across the country are playing the game of social media and what strategies they put into place to be impactful and successful. I wanted to learn the value teams found in social media and how social media impacts the organizations as a whole, specifically in revenue generation. Most importantly, I wanted to learn how teams are engaging with fans and how social media has changed the world of sports. This research includes insights from various individuals in the industry as well as survey data from W. P. Carey students. The accumulation of this thesis has resulted in a closer look into social media in the sports industry and how teams are measuring success in the digital space.
When it comes to my story, I wanted to make sure I told one that was interesting, relevant and worthwhile. I felt lost for quite some time in regards to what direction I wanted to take with my thesis. After meeting with Dan Moriarty and Kevin Brilliant of the Chicago Bulls during an outreach trip with the Sports Business Association, I knew I wanted to gain more insight into how teams are telling their digital stories and connecting with their fans. I wanted to learn more about how teams across the country are playing the game of social media and what strategies they put into place to be impactful and successful. I wanted to learn the value teams found in social media and how social media impacts the organizations as a whole, specifically in revenue generation. Most importantly, I wanted to learn how teams are engaging with fans and how social media has changed the world of sports. This research includes insights from various individuals in the industry as well as survey data from W. P. Carey students. The accumulation of this thesis has resulted in a closer look into social media in the sports industry and how teams are measuring success in the digital space.
ContributorsMaguire, Allison Marie (Author) / Eaton, John (Thesis director) / Mokwa, Michael (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Department of Marketing (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05