Matching Items (299)
Description
The ability to identify unoccupied resources in the radio spectrum is a key capability for opportunistic users in a cognitive radio environment. This paper draws upon and extends geometrically based ideas in statistical signal processing to develop estimators for the rank and the occupied subspace in a multi-user environment from multiple temporal samples of the signal received at a single antenna. These estimators enable identification of resources, such as the orthogonal complement of the occupied subspace, that may be exploitable by an opportunistic user. This concept is supported by simulations showing the estimation of the number of users in a simple CDMA system using a maximum a posteriori (MAP) estimate for the rank. It was found that with suitable parameters, such as high SNR, sufficient number of time epochs and codes of appropriate length, the number of users could be correctly estimated using the MAP estimator even when the noise variance is unknown. Additionally, the process of identifying the maximum likelihood estimate of the orthogonal projector onto the unoccupied subspace is discussed.
ContributorsBeaudet, Kaitlyn (Author) / Cochran, Douglas (Thesis advisor) / Turaga, Pavan (Committee member) / Berisha, Visar (Committee member) / Arizona State University (Publisher)
Created2014
Description
Motion estimation is a core task in computer vision and many applications utilize optical flow methods as fundamental tools to analyze motion in images and videos. Optical flow is the apparent motion of objects in image sequences that results from relative motion between the objects and the imaging perspective. Today, optical flow fields are utilized to solve problems in various areas such as object detection and tracking, interpolation, visual odometry, etc. In this dissertation, three problems from different areas of computer vision and the solutions that make use of modified optical flow methods are explained.
The contributions of this dissertation are approaches and frameworks that introduce i) a new optical flow-based interpolation method to achieve minimally divergent velocimetry data, ii) a framework that improves the accuracy of change detection algorithms in synthetic aperture radar (SAR) images, and iii) a set of new methods to integrate Proton Magnetic Resonance Spectroscopy (1HMRSI) data into threedimensional (3D) neuronavigation systems for tumor biopsies.
In the first application an optical flow-based approach for the interpolation of minimally divergent velocimetry data is proposed. The velocimetry data of incompressible fluids contain signals that describe the flow velocity. The approach uses the additional flow velocity information to guide the interpolation process towards reduced divergence in the interpolated data.
In the second application a framework that mainly consists of optical flow methods and other image processing and computer vision techniques to improve object extraction from synthetic aperture radar images is proposed. The proposed framework is used for distinguishing between actual motion and detected motion due to misregistration in SAR image sets and it can lead to more accurate and meaningful change detection and improve object extraction from a SAR datasets.
In the third application a set of new methods that aim to improve upon the current state-of-the-art in neuronavigation through the use of detailed three-dimensional (3D) 1H-MRSI data are proposed. The result is a progressive form of online MRSI-guided neuronavigation that is demonstrated through phantom validation and clinical application.
The contributions of this dissertation are approaches and frameworks that introduce i) a new optical flow-based interpolation method to achieve minimally divergent velocimetry data, ii) a framework that improves the accuracy of change detection algorithms in synthetic aperture radar (SAR) images, and iii) a set of new methods to integrate Proton Magnetic Resonance Spectroscopy (1HMRSI) data into threedimensional (3D) neuronavigation systems for tumor biopsies.
In the first application an optical flow-based approach for the interpolation of minimally divergent velocimetry data is proposed. The velocimetry data of incompressible fluids contain signals that describe the flow velocity. The approach uses the additional flow velocity information to guide the interpolation process towards reduced divergence in the interpolated data.
In the second application a framework that mainly consists of optical flow methods and other image processing and computer vision techniques to improve object extraction from synthetic aperture radar images is proposed. The proposed framework is used for distinguishing between actual motion and detected motion due to misregistration in SAR image sets and it can lead to more accurate and meaningful change detection and improve object extraction from a SAR datasets.
In the third application a set of new methods that aim to improve upon the current state-of-the-art in neuronavigation through the use of detailed three-dimensional (3D) 1H-MRSI data are proposed. The result is a progressive form of online MRSI-guided neuronavigation that is demonstrated through phantom validation and clinical application.
ContributorsKanberoglu, Berkay (Author) / Frakes, David (Thesis advisor) / Turaga, Pavan (Thesis advisor) / Spanias, Andreas (Committee member) / Berisha, Visar (Committee member) / Arizona State University (Publisher)
Created2018
Description
When dancers are granted agency over music, as in interactive dance systems, the actors are most often concerned with the problem of creating a staged performance for an audience. However, as is reflected by the above quote, the practice of Argentine tango social dance is most concerned with participants internal experience and their relationship to the broader tango community. In this dissertation I explore creative approaches to enrich the sense of connection, that is, the experience of oneness with a partner and complete immersion in music and dance for Argentine tango dancers by providing agency over musical activities through the use of interactive technology. Specifically, I create an interactive dance system that allows tango dancers to affect and create music via their movements in the context of social dance. The motivations for this work are multifold: 1) to intensify embodied experience of the interplay between dance and music, individual and partner, couple and community, 2) to create shared experience of the conventions of tango dance, and 3) to innovate Argentine tango social dance practice for the purposes of education and increasing musicality in dancers.
ContributorsBrown, Courtney Douglass (Author) / Paine, Garth (Thesis advisor) / Feisst, Sabine (Committee member) / Turaga, Pavan (Committee member) / Arizona State University (Publisher)
Created2017
Description
The human motion is defined as an amalgamation of several physical traits such as bipedal locomotion, posture and manual dexterity, and mental expectation. In addition to the “positive” body form defined by these traits, casting light on the body produces a “negative” of the body: its shadow. We often interchangeably use with silhouettes in the place of shadow to emphasize indifference to interior features. In a manner of speaking, the shadow is an alter ego that imitates the individual.
The principal value of shadow is its non-invasive behaviour of reflecting precisely the actions of the individual it is attached to. Nonetheless we can still think of the body’s shadow not as the body but its alter ego.
Based on this premise, my thesis creates an experiential system that extracts the data related to the contour of your human shape and gives it a texture and life of its own, so as to emulate your movements and postures, and to be your extension. In technical terms, my thesis extracts abstraction from a pre-indexed database that could be generated from an offline data set or in real time to complement these actions of a user in front of a low-cost optical motion capture device like the Microsoft Kinect. This notion could be the system’s interpretation of the action which creates modularized art through the abstraction’s ‘similarity’ to the live action.
Through my research, I have developed a stable system that tackles various connotations associated with shadows and the need to determine the ideal features that contribute to the relevance of the actions performed. The implication of Factor Oracle [3] pattern interpretation is tested with a feature bin of videos. The system also is flexible towards several methods of Nearest Neighbours searches and a machine learning module to derive the same output. The overall purpose is to establish this in real time and provide a constant feedback to the user. This can be expanded to handle larger dynamic data.
In addition to estimating human actions, my thesis best tries to test various Nearest Neighbour search methods in real time depending upon the data stream. This provides a basis to understand varying parameters that complement human activity recognition and feature matching in real time.
The principal value of shadow is its non-invasive behaviour of reflecting precisely the actions of the individual it is attached to. Nonetheless we can still think of the body’s shadow not as the body but its alter ego.
Based on this premise, my thesis creates an experiential system that extracts the data related to the contour of your human shape and gives it a texture and life of its own, so as to emulate your movements and postures, and to be your extension. In technical terms, my thesis extracts abstraction from a pre-indexed database that could be generated from an offline data set or in real time to complement these actions of a user in front of a low-cost optical motion capture device like the Microsoft Kinect. This notion could be the system’s interpretation of the action which creates modularized art through the abstraction’s ‘similarity’ to the live action.
Through my research, I have developed a stable system that tackles various connotations associated with shadows and the need to determine the ideal features that contribute to the relevance of the actions performed. The implication of Factor Oracle [3] pattern interpretation is tested with a feature bin of videos. The system also is flexible towards several methods of Nearest Neighbours searches and a machine learning module to derive the same output. The overall purpose is to establish this in real time and provide a constant feedback to the user. This can be expanded to handle larger dynamic data.
In addition to estimating human actions, my thesis best tries to test various Nearest Neighbour search methods in real time depending upon the data stream. This provides a basis to understand varying parameters that complement human activity recognition and feature matching in real time.
ContributorsSeshasayee, Sudarshan Prashanth (Author) / Sha, Xin Wei (Thesis advisor) / Turaga, Pavan (Thesis advisor) / Tinapple, David A (Committee member) / Arizona State University (Publisher)
Created2016
Description
This study examined upper extremity function, including manual dexterity, in chronic stroke survivors following a 10-week high intensity interval treadmill walking intervention. Six stroke survivors completed two 35-minute high intensity interval treadmill walking sessions based on ventilatory threshold per week. In addition, each participant completed one 30-minute low-intensity walking session at home. Participants completed upper extremity and manual dexterity testing at baseline, acutely, and after the 10-week intervention. Contrary to the prediction made, significant improvements in both paretic and non-paretic upper-extremity function including manual dexterity were not found. While time to complete the Nine Hole Peg Test (9HPB) somewhat decreased and the number of blocks transferred in the Box and Blocks Test (BBT) slightly increased, results were not found to be statistically significant. The results do suggest, nonetheless, that high intensity interval treadmill training may lead to improvements in upper extremity function and potentially daily living in chronic stroke survivors.
ContributorsHatty, Laura Elizabeth (Author) / Ringenbach, Shannon (Thesis director) / Bosch, Pamela (Committee member) / Holzapfel, Simon (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Background: Physical inactivity is a major cause of obesity, hypertension, cardiovascular disease, and diabetes and has become a major public health problem. Physical inactivity is detrimental to one's health, but it has also created a significant healthcare burden. Within the past decade, many health-based interventions have been implemented to encourage physically inactive individuals to adopt a more active lifestyle. These health-based interventions have used social media websites, particularly Facebook, to establish social support between the participants of those interventions. There is currently limited research on this topic. This study aims to add to that literature by exploring strategies to encourage participants of health-based interventions to interact with a Facebook group. Purpose: An exercise and nutrition-based intervention called Athletes for Life (AFL) has been using a Facebook page over the past 2.5 years to establish social support between participants of the program, among other functions. The level of interaction that participants had with the Facebook page has declined over the past year. The objective of this study is to redesign and refine the AFL Facebook page so that it is more appealing and interactive to AFL participants. Methods: Redesigning and refining the AFL Facebook page were achieved through three strategies. The first strategy was to recruit approximately twenty participants to the new AFL Facebook group. The next strategy was to select a participant to become the group champion who would post encouraging content on the Facebook group wall. The final strategy was to maintain the consistency with which participants liked and viewed posts on the group wall. Results: The results of this study showed nine participants joined the group and these participants had a combined total of 62 likes and 110 views on the group wall over an eleven-week period. Participants interacted with the content posted by the Facebook group administrators on a consistent basis, but only one participant posted a recipe to the group wall. Measuring the level of interaction for each individual post was significant because it illustrated that the level of interaction participants had with posts depended on the identity of the posts' author. Conclusions: Future research should test the effectiveness of a Facebook group page for promoting physical activity and implementing the suggestions from study participants to increase Facebook usage.
ContributorsNasef, Amr Sherif (Author) / Crespo, Noe (Thesis director) / Hekler, Eric (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The Student Health Outreach for Wellness (SHOW) is a free, student-led interprofessional clinic and community outreach initiative that aims to serve individuals experiencing homelessness in Phoenix, AZ. Individuals experiencing homelessness face many situational and financial barriers to finding healthcare. In order to better understand these barriers, a community needs assessment (CNA) was conducted in Fall 2014 on the Human Services Campus (HSC), a hub of resources for the population. Results indicated chronic disease is moderately prevalent (37.21% and 27.91% reported obesity and hypertension, respectively, among others). Since chronic diseases can lead to more severe health issues, it is imperative to address, manage, and avoid these conditions. Health education programs are a key component of the SHOW clinic model and a means to address chronic disease. The Health Belief Model (HBM) is a theory-based behavior change model used in programs to increase patient adherence to and promotion of preventative health behaviors. SHOW health education programs will use the constructs of this model to inform program development. Since many student volunteers are not well-versed in health education literature, a SHOW Program Development Guide based on the HBM has been created. The guide will help ensure SHOW delivers high-quality and efficacious programs that have a long-lasting impact on patients now and as the organization continues to grow.
ContributorsReeve, Emma Christine (Author) / Hoffner, Kristin (Thesis director) / Harrell, Susan (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The purpose of this study was to determine if there was a relationship between the constructs of motivational theories, Self-Determination Theory and Health Belief Model, and adherence to a home exercise program. The constructs of Self-Determination Theory are autonomy, competence, and social relatedness. The constructs of Health Belief Model are perceived benefits, perceived barriers, perceived severity, and perceived susceptibility. Participants were receiving therapy at two outpatient clinics located in the Phoenix metropolitan area (n=40). Autonomy was assessed with a modified Treatment Self-Regulation Questionnaire. Competence was assessed with a modified Perceived Competence Scale. Social relatedness was assessed with a modified Health Care Climate Questionnaire. Perceived benefits and barriers were measured with a modified Exercise Benefits/Barriers Scale. Perceived severity and susceptibility were measured with a modified Health Beliefs Questionnaire. Adherence was measured with one Likert-type question that was created by the researchers. The data was scored and analyzed with the scoring guidelines provided by the questionnaires and the statistics software, IBM Statistical Package for the Social Sciences. The results showed that competence was the only construct that was significantly correlated with home exercise program adherence. The results from this study should be used for further research that focuses on creating a competence-supportive environment in physical therapy settings.
ContributorsAutrey, Makenna Noelle (Co-author) / Hamilton, Marissa (Co-author) / Hoffner, Kristin (Thesis director) / Broman, Tannah (Committee member) / School of Nutrition and Health Promotion (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
According to the Center for Disease Control, 1 in every 3 individuals will fall in their lifetime. Treadmill perturbation training has been a beneficial tool to increase reactive postural control and decrease the amount of falls. This study looked at the extent of the training effects on 29 healthy young adults to evaluate if stepping improvements in one direction could generalize to improvements in the quality of stepping in other directions. Outcome variables of Margin of Stability (MOS), step length, and step latency were evaluated for all 15 participants trained with forward perturbations and 14 participants trained with backward perturbations. From the paired t-tests, there were limited significant improvements in stepping with regards to motor learning and generalization. The only significant outcome was an increase in step length for the participants who trained in the backward direction (p=0.014; p<0.05). However, this significant increase in step length for this backward group did not generalize when the participants stepped in the forward direction post training. From the correlation tests, there was a significant, moderate correlation between motor learning and generalization (rho =0.527, p= 0.043; p<0.05), thus suggesting there may be a relationship between the amount of learning and the amount of generalization observed. Further evaluation of the second step and the foot motion during stepping may reveal more information and explain the changes in stepping to describe how healthy young adults were able to regain balance with each perturbation given.
ContributorsNowak, Rachael Teresa (Author) / Peterson, Daniel (Thesis director) / Dounskaia, Natalia (Committee member) / School of Nutrition and Health Promotion (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2018-12