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.
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One of the main challenges in planetary robotics is to traverse the shortest path through a set of waypoints. The shortest distance between any two waypoints is a direct linear traversal. Often times, there are physical restrictions that prevent a rover form traversing straight to a waypoint. Thus, knowledge of the terrain is needed prior to traversal. The Digital Terrain Model (DTM) provides information about the terrain along with waypoints for the rover to traverse. However, traversing a set of waypoints linearly is burdensome, as the rovers would constantly need to modify their orientation as they successively approach waypoints. Although there are various solutions to this problem, this research paper proposes the smooth traversability of the rover using splines as a quick and easy implementation to traverse a set of waypoints. In addition, a rover was used to compare the smoothness of the linear traversal along with the spline interpolations. The data collected illustrated that spline traversals had a less rate of change in the velocity over time, indicating that the rover performed smoother than with linear paths.
ContributorsKamasamudram, Anurag (Author) / Saripalli, Srikanth (Thesis advisor) / Fainekos, Georgios (Thesis advisor) / Turaga, Pavan (Committee member) / Arizona State University (Publisher)
Created2013
Description
As the complexity of robotic systems and applications grows rapidly, development of high-performance, easy to use, and fully integrated development environments for those systems is inevitable. Model-Based Design (MBD) of dynamic systems using engineering software such as Simulink® from MathWorks®, SciCos from Metalau team and SystemModeler® from Wolfram® is quite popular nowadays. They provide tools for modeling, simulation, verification and in some cases automatic code generation for desktop applications, embedded systems and robots. For real-world implementation of models on the actual hardware, those models should be converted into compilable machine code either manually or automatically. Due to the complexity of robotic systems, manual code translation from model to code is not a feasible optimal solution so we need to move towards automated code generation for such systems. MathWorks® offers code generation facilities called Coder® products for this purpose. However in order to fully exploit the power of model-based design and code generation tools for robotic applications, we need to enhance those software systems by adding and modifying toolboxes, files and other artifacts as well as developing guidelines and procedures. In this thesis, an effort has been made to propose a guideline as well as a Simulink® library, StateFlow® interface API and a C/C++ interface API to complete this toolchain for NAO humanoid robots. Thus the model of the hierarchical control architecture can be easily and properly converted to code and built for implementation.
ContributorsRaji Kermani, Ramtin (Author) / Fainekos, Georgios (Thesis advisor) / Lee, Yann-Hang (Committee member) / Sarjoughian, Hessam S. (Committee member) / Arizona State University (Publisher)
Created2013
Description
The academic literature on science communication widely acknowledges a problem: science communication between experts and lay audiences is important, but it is not done well. General audience popular science books, however, carry a reputation for clear science communication and are understudied in the academic literature. For this doctoral dissertation, I utilize Sam Harris's The Moral Landscape, a general audience science book on the particularly thorny topic of neuroscientific approaches to morality, as a case-study to explore the possibility of using general audience science books as models for science communication more broadly. I conduct a literary analysis of the text that delimits the scope of its project, its intended audience, and the domains of science to be communicated. I also identify seven literary aspects of the text: three positive aspects that facilitate clarity and four negative aspects that interfere with lay public engagement. I conclude that The Moral Landscape relies on an assumed knowledge base and intuitions of its audience that cannot reasonably be expected of lay audiences; therefore, it cannot properly be construed as popular science communication. It nevertheless contains normative lessons for the broader science project, both in literary aspects to be salvaged and literary aspects and concepts to consciously be avoided and combated. I note that The Moral Landscape's failings can also be taken as an indication that typical descriptions of science communication offer under-detailed taxonomies of both audiences for science communication and the varieties of science communication aimed at those audiences. Future directions of study include rethinking appropriate target audiences for science literacy projects and developing a more discriminating taxonomy of both science communication and lay publics.
ContributorsJohnson, Nathan W (Author) / Robert, Jason S (Thesis advisor) / Creath, Richard (Committee member) / Martinez, Jacqueline (Committee member) / Sylvester, Edward (Committee member) / Lynch, John (Committee member) / Arizona State University (Publisher)
Created2013
Description
After decades of dormancy, character is re-emerging as an important research topic among organizational leadership researchers in response to the need to better explain the source of certain exemplary and ethical leader performance (Hannah & Avolio, 2011; Leonard, 1997; Thompson & Riggio, 2010; Wright & Goodstein, 2007). However, efforts to operationalize character are criticized for their abstract and idealistic trait-based conceptualizations that fail to capture the reality of leadership and situational dynamics (Conger & Hollenbeck, 2010). The purpose of this study is to develop a more robust theoretical approach to character that is empirically grounded in the real life complexities of leadership. Combat provides the context for this study because the adversity of such an extreme context tends to make character a more salient and readily observable phenomenon than in more conventional organizational contexts (Wright & Quick, 2011; Hannah, Uhl-Bien, Avolio, & Cavarretta, 2009). I employed an ethnographic grounded theory design to gain a unique insider's perspective absent in many studies of leader character (Charmaz, 2009; Parry & Meindl, 2002). Data collection involved (1) physically embedding for six months with U.S. Army small unit infantry leaders operating in combat in Afghanistan; (2) participant observation in the full range of combat activities engaged in by these leaders; and (3) in-depth semi-structured interviews with key informants. An important contribution of this study is that the emergent concept of leader character is fully situated in the leader's social and environmental context represented by the leader's inner struggle to resist the adversity of combat and uphold the standards of leadership. In this dialectical framework, certain agentic resources important to resolving this inner struggle emerge as the locus of leader character. This agency-based concept of character is rooted in the internalization of the standards of leadership through identity-conferring normative commitments and entails particular motivational and volitional capacities. These produce a distinct mode of functioning--a strong form of personal moral agency--characterized by the leader's willingness to sacrifice in upholding standards in the face of adversity. This primacy of leader agency over adversity is the hallmark of leader character--what I call the character to lead.
ContributorsJennings, Peter L. (Author) / Corley, Kevin (Thesis advisor) / Waldman, David (Thesis advisor) / Hannah, Sean T (Committee member) / Arizona State University (Publisher)
Created2013
Description
The development of advanced, anthropomorphic artificial hands aims to provide upper extremity amputees with improved functionality for activities of daily living. However, many state-of-the-art hands have a large number of degrees of freedom that can be challenging to control in an intuitive manner. Automated grip responses could be built into artificial hands in order to enhance grasp stability and reduce the cognitive burden on the user. To this end, three studies were conducted to understand how human hands respond, passively and actively, to unexpected perturbations of a grasped object along and about different axes relative to the hand. The first study investigated the effect of magnitude, direction, and axis of rotation on precision grip responses to unexpected rotational perturbations of a grasped object. A robust "catch-up response" (a rapid, pulse-like increase in grip force rate previously reported only for translational perturbations) was observed whose strength scaled with the axis of rotation. Using two haptic robots, we then investigated the effects of grip surface friction, axis, and direction of perturbation on precision grip responses for unexpected translational and rotational perturbations for three different hand-centric axes. A robust catch-up response was observed for all axes and directions for both translational and rotational perturbations. Grip surface friction had no effect on the stereotypical catch-up response. Finally, we characterized the passive properties of the precision grip-object system via robot-imposed impulse perturbations. The hand-centric axis associated with the greatest translational stiffness was different than that for rotational stiffness. This work expands our understanding of the passive and active features of precision grip, a hallmark of human dexterous manipulation. Biological insights such as these could be used to enhance the functionality of artificial hands and the quality of life for upper extremity amputees.
ContributorsDe Gregorio, Michael (Author) / Santos, Veronica J. (Thesis advisor) / Artemiadis, Panagiotis K. (Committee member) / Santello, Marco (Committee member) / Sugar, Thomas (Committee member) / Helms Tillery, Stephen I. (Committee member) / Arizona State University (Publisher)
Created2013
Description
Human fingertips contain thousands of specialized mechanoreceptors that enable effortless physical interactions with the environment. Haptic perception capabilities enable grasp and manipulation in the absence of visual feedback, as when reaching into one's pocket or wrapping a belt around oneself. Unfortunately, state-of-the-art artificial tactile sensors and processing algorithms are no match for their biological counterparts. Tactile sensors must not only meet stringent practical specifications for everyday use, but their signals must be processed and interpreted within hundreds of milliseconds. Control of artificial manipulators, ranging from prosthetic hands to bomb defusal robots, requires a constant reliance on visual feedback that is not entirely practical. To address this, we conducted three studies aimed at advancing artificial haptic intelligence. First, we developed a novel, robust, microfluidic tactile sensor skin capable of measuring normal forces on flat or curved surfaces, such as a fingertip. The sensor consists of microchannels in an elastomer filled with a liquid metal alloy. The fluid serves as both electrical interconnects and tunable capacitive sensing units, and enables functionality despite substantial deformation. The second study investigated the use of a commercially-available, multimodal tactile sensor (BioTac sensor, SynTouch) to characterize edge orientation with respect to a body fixed reference frame, such as a fingertip. Trained on data from a robot testbed, a support vector regression model was developed to relate haptic exploration actions to perception of edge orientation. The model performed comparably to humans for estimating edge orientation. Finally, the robot testbed was used to perceive small, finger-sized geometric features. The efficiency and accuracy of different haptic exploratory procedures and supervised learning models were assessed for estimating feature properties such as type (bump, pit), order of curvature (flat, conical, spherical), and size. This study highlights the importance of tactile sensing in situations where other modalities fail, such as when the finger itself blocks line of sight. Insights from this work could be used to advance tactile sensor technology and haptic intelligence for artificial manipulators that improve quality of life, such as prosthetic hands and wheelchair-mounted robotic hands.
ContributorsPonce Wong, Ruben Dario (Author) / Santos, Veronica J (Thesis advisor) / Artemiadis, Panagiotis K (Committee member) / Helms Tillery, Stephen I (Committee member) / Posner, Jonathan D (Committee member) / Runger, George C. (Committee member) / Arizona State University (Publisher)
Created2013
Description
Electromyogram (EMG)-based control interfaces are increasingly used in robot teleoperation, prosthetic devices control and also in controlling robotic exoskeletons. Over the last two decades researchers have come up with a plethora of decoding functions to map myoelectric signals to robot motions. However, this requires a lot of training and validation data sets, while the parameters of the decoding function are specific for each subject. In this thesis we propose a new methodology that doesn't require training and is not user-specific. The main idea is to supplement the decoding functional error with the human ability to learn inverse model of an arbitrary mapping function. We have shown that the subjects gradually learned the control strategy and their learning rates improved. We also worked on identifying an optimized control scheme that would be even more effective and easy to learn for the subjects. Optimization was done by taking into account that muscles act in synergies while performing a motion task. The low-dimensional representation of the neural activity was used to control a two-dimensional task. Results showed that in the case of reduced dimensionality mapping, the subjects were able to learn to control the device in a slower pace, however they were able to reach and retain the same level of controllability. To summarize, we were able to build an EMG-based controller for robot devices that would work for any subject, without any training or decoding function, suggesting human-embedded controllers for robotic devices.
ContributorsAntuvan, Chris Wilson (Author) / Artemiadis, Panagiotis (Thesis advisor) / Muthuswamy, Jitendran (Committee member) / Santos, Veronica J (Committee member) / Arizona State University (Publisher)
Created2013
Description
Linear Temporal Logic is gaining increasing popularity as a high level specification language for robot motion planning due to its expressive power and scalability of LTL control synthesis algorithms. This formalism, however, requires expert knowledge and makes it inaccessible to non-expert users. This thesis introduces a graphical specification environment to create high level motion plans to control robots in the field by converting a visual representation of the motion/task plan into a Linear Temporal Logic (LTL) specification. The visual interface is built on the Android tablet platform and provides functionality to create task plans through a set of well defined gestures and on screen controls. It uses the notion of waypoints to quickly and efficiently describe the motion plan and enables a variety of complex Linear Temporal Logic specifications to be described succinctly and intuitively by the user without the need for the knowledge and understanding of LTL specification. Thus, it opens avenues for its use by personnel in military, warehouse management, and search and rescue missions. This thesis describes the construction of LTL for various scenarios used for robot navigation using the visual interface developed and leverages the use of existing LTL based motion planners to carry out the task plan by a robot.
ContributorsSrinivas, Shashank (Author) / Fainekos, Georgios (Thesis advisor) / Baral, Chitta (Committee member) / Burleson, Winslow (Committee member) / Arizona State University (Publisher)
Created2013
Description
"YouTube Shakespeares" is a study of Shakespeare online videos and the people who create, upload, and view them on YouTube. Employing an interdisciplinary approach, this work is a remix of theories and methodologies from literary, performance, (social) media, fan, and Internet studies that expands the field of Shakespeare studies. This dissertation explores the role of YouTube users and their activities, the expansion of literary research methods onto digital media venues, YouTube as site of Shakespeare performance, and YouTube Shakespeares' fan communities. It analyzes a broad array of Shakespeare visual performances including professional and user-generated mashups, remixes, film clips, auditions, and high school performances. A rich avenue for the study of people's viewing and reception of Shakespeare, YouTube tests the (un)limitations of Shakespeare adaptation. This work explores the ethical implications of researching performances that include human subjects, arguing that their presence frequently complicates common concepts of public and private identities. Although YouTube is a "published" forum for social interactivity and video repository, this work urges digital humanities scholars to recognize and honor the human users entailed in the videos not as text, but as human subjects. Shifting the study focus to human subjects demands a revision of research methods and publications protocols as the researcher repositions herself into the role of virtual ethnographer. "YouTube Shakespeares" develops its own ethics-based, online research method, which includes seeking Institutional Board Review approval and online interviews. The second half of the dissertation shifts from methodology to theorizing YouTube Shakespeares' performance spaces as analogs to the interactive and imaginary areas of Shakespeare's early modern theatre. Additionally, this work argues that YouTube Shakespeares' creators and commentators are fans. "YouTube Shakespeares" is one of the first Shakespeare-centric studies to employ fan studies as a critical lens to explore the cultural significance and etiquette of people's online Shakespeare performance activities. The work ends with a conversation about the issues of ephemerality, obsolescence, and concerns about the instability of digital and online materials, noting the risk of evidentiary loss of research materials is far outweighed by a scholarly critical registration of YouTube in the genealogy of Shakespeare performance.
ContributorsFazel, Valerie Margaret (Author) / Thompson, Ayanna (Thesis advisor) / Ryner, Bradley (Committee member) / Fox, Cora (Committee member) / Arizona State University (Publisher)
Created2013
Description
This dissertation provides a critical analysis of public administration's understanding of the relationship between rational thought and action in its discourse on ethics. It argues that rationalist ethics assume a particular relationship between thought and action: that good knowledge leads to good, proper action. While there have been many critiques of rationalist administrative ethics, scholars have not examined the way in which rationalism persists in the way in which the teaching of ethics is conducted. The use of the case study figures prominently in this. Thus, the dissertation explores the historical and theoretical intersection of rationalism, ethics, and teaching through the lens of the case study. It begins with a history of the pedagogical use of the case study and the institutional transformations of the university. While conventional accounts of the field locate its founding in the United States in the municipal reform movement, here the founding of the field of public administration is recast through connections to reforms in the university including changes in epistemic assumptions, pedagogical methods, and curricular changes in ethics in which the case study is central and remains so as the field develops. The dissertation then considers scholarship in public administration that raises questions about rationalist ethics. Three critical approaches are explored: recognition of the uncertainty and complexity of administrative practice, critique as unmasking of power relationships, and the shift of ethics from an epistemological to an ontological inquiry. The dissertation builds on the work in this third approach and shows how it attempts to articulate a non-rationalist, or immanent, ethics. This ethics is concerned with exploring the conditions that make possible mutually beneficial relationships and meaningful lives from which categorical norms of the good life could emerge. Drawing on the philosophy of Gilles Deleuze and Felix Guattari, it is argued that the distinction Deleuze and Guattari make between "arborescent" and "rhizomatic" knowledge gets to the root of the tension between thought and action and offers an innovative and useful way to advance an immanent, non-rational ethics. The challenge digital technologies and the information society present to the field is considered to illustrate the need to rethink administrative ethics and also the particular usefulness of Deleuze and Guattari in doing so. The dissertation concludes with a discussion of pedagogical practices and classroom examples that encourage a rhizomatic understanding of the theory and practice of public administration.
ContributorsCallen, Jeffrey Craig (Author) / Catlaw, Thomas J (Thesis advisor) / Corley, Elizabeth (Committee member) / Kim, Yushim (Committee member) / Arizona State University (Publisher)
Created2013