ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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- Creators: Shen, Wei
- Creators: Sugar, Thomas
Description
This work endeavors to lay a solid foundation for the exploration and the considerations of exoskeletons, exosuits, and medical devices concerning proprioceptive feedback. This investigation is situated at the nexus of engineering, neuroscience, and rehabilitation medicine, striving to cultivate a holistic understanding of how mechanical augmentation, interfaced synergistically with human proprioception, can foster enhanced mobility and safety. This is especially pertinent for individuals with compromised motor functions.British Neurologist Oliver Wolf Sacks in 1985 published “The Man who Mistook His Wife for a Hat” a series of his most memorable neurological case describing the brain's strangest pathways. One of these cases is “The Disembodied Lady”, Christina a 27-year-old woman that lost entirely the sense of proprioception due to polyneuropathy. This caused her to not be able to control her body, and she declares that “I feel the wind on my arms and face, and then I know, faintly, I have arms and a face. It’s not the real thing, but it’s something—it lifts this horrible, dead veil for a while. ” Finally, she was able to control her body using vision alone. Dr. Sacks introduced, for the first time, the importance of proprioception, as the sense of position of body parts relative to other parts of the body, to western culture. This document’s mission is to identify unexplored concepts in the literature regarding exoskeletons, wearables and assistive technology and a user’s proprioception, embodiment and utilization when wearing devices. Dr. Philipp Beckerle suggests the need to research the connections between wearable hardware and human sense of proprioception. He also emphasizes the need for functional assessment protocols for wearables devices and the role of embodiment. He criticizes the current commercially available upper-limb prostheses since they only restore limited functions and therefore impede embodiment.
This document’s goal is to identify operative solutions through the adaptation of existing technologies and to use effective solutions to improve the quality of life of people suffering from pathologies or traumatic injuries.
ContributorsVignola, Claudio (Author) / Sugar, Thomas (Thesis advisor) / Redkar, Sangram (Committee member) / McDaniels, Troy (Committee member) / Arizona State University (Publisher)
Created2023
Description
Soft robotics has garnered attention for its substantial prospective in various domains, such as manipulation and interactions with humans, by offering competitive advantages against rigid robotic systems, including inherent compliance and variable stiffness. Despite these benefits, their theoretically infinite degrees of freedom and prominent nonlinearities pose significant challenges in developing dynamic models and guiding the robots along desired paths. Additionally, soft robots may exhibit rigid behaviors and potentially collide with their surroundings during path tracking tasks, particularly when possible contact points are unknown. In this dissertation, reduced-order models are used to describe the behaviors of three different soft robot designs, including both linear parameter varying (LPV) and augmented rigid robot (ARR) models. While the reduced-order model captures the majority of the soft robot's dynamics, modeling uncertainties notably remain. Non-repeated modeling uncertainties are addressed by categorizing them as a lumped disturbance, employing two methodologies, $H_\infty$ method and nonlinear disturbance observer (NDOB) based sliding mode control, for its rejection. For repeated disturbances, an iterative learning control (ILC) with a P-type learning function is implemented to enhance trajectory tracking efficacy. Furthermore,for non-repeated disturbances, the NDOB facilitates the contact estimation, and its results are jointly used with a switching algorithm to modify the robot trajectories. The stability proof of all controllers and corresponding simulation and experimental results are provided. For a path tracking task of a soft robot with multi-segments, a robust control strategy that combines a LPV model with an innovative improved nonlinear disturbance observer-based adaptive sliding mode control (INASMC). The control framework employs a first-order LPV model for dynamic representation, leverages an improved disturbance observer for accurate disturbance forecasting, and utilizes adaptive sliding mode control to effectively counteract uncertainties. The tracking error under the proposed controller is proven to be asymptotically stable, and the controller's effectiveness is is validated with simulation and experimental results. Ultimately, this research mitigates the inherent uncertainty in soft robot modeling, thereby enhancing their functionality in contact-intensive tasks.
ContributorsQIAO, ZHI (Author) / Zhang, Wenlong (Thesis advisor) / Marvi, Hamidreza (Committee member) / Lee, Hyunglae (Committee member) / Berman, Spring (Committee member) / Sugar, Thomas (Committee member) / Arizona State University (Publisher)
Created2023
Description
Walking and mobility are essential aspects of our daily lives, enabling us to engage in various activities. Gait disorders and impaired mobility are widespread challenges faced by older adults and people with neurological injuries, as these conditions can significantly impact their quality of life, leading to a loss of independence and an increased risk of mortality. In response to these challenges, rehabilitation, and assistive robotics have emerged as promising alternatives to conventional gait therapy, offering potential solutions that are less labor-intensive and costly. Despite numerous advances in wearable lower-limb robotics, their current applicability remains confined to laboratory settings. To expand their utility to broader gait impairments and daily living conditions, there is a pressing need for more intelligent robot controllers. In this dissertation, these challenges are tackled from two perspectives: First, to improve the robot's understanding of human motion and intentions which is crucial for assistive robot control, a robust human locomotion estimation technique is presented, focusing on measuring trunk motion. Employing an invariant extended Kalman filtering method that takes sensor misplacement into account, improved convergence properties over the existing methods for different locomotion modes are shown. Secondly, to enhance safe and effective robot-aided gait training, this dissertation proposes to directly learn from physical therapists' demonstrations of manual gait assistance in post-stroke rehabilitation.
Lower-limb kinematics of patients and assistive force applied by therapists to the patient's leg are measured using a wearable sensing system which includes a custom-made force sensing array. The collected data is then used to characterize a therapist's strategies. Preliminary analysis indicates that knee extension and weight-shifting play pivotal roles in shaping a therapist's assistance strategies, which are then incorporated into a virtual impedance model that effectively captures high-level therapist behaviors throughout a complete training session. Furthermore, to introduce safety constraints in the design of such controllers, a safety-critical learning framework is explored through theoretical analysis and simulations. A safety filter incorporating an online iterative learning component is introduced to bring robust safety guarantees for gait robotic assistance and training, addressing challenges such as stochasticity and the absence of a known prior dynamic model.
ContributorsRezayat Sorkhabadi, Seyed Mostafa (Author) / Zhang, Wenlong (Thesis advisor) / Berman, Spring (Committee member) / Lee, Hyunglae (Committee member) / Marvi, Hamid (Committee member) / Sugar, Thomas (Committee member) / Arizona State University (Publisher)
Created2023
Description
In this study I investigate the organizational mechanisms (pathways) through which strategic investors can help a firm improve performance. Many commercial banks in China have recently invited foreign banks as strategic investors since China’s entry into the World Trade Organization (WTO), hoping to gain managerial and technological knowhow from the foreign banks. Using Shanghai Pudong Development Bank as a representative example, I conduct an in-depth qualitative analysis about how the joining of Citi Bank as a strategic investor has helped the local Chinese bank improve its financial performance. On the basis of a comprehensive review of the relevant literature, I first develop a theoretical model that describes the organizational mechanisms (pathways) through which foreign strategic investors can influence the local bank’s performance. Specifically, by participation in corporate governance, the foreign strategic investor can have a positive influence over the local bank’s strategy development, operational targets, incentive systems, and organizational culture, which consequently lead to improvements in the local banks operations and financial performance. I then use a case study method to substantiate the logic and the pathways of the model with the detailed information collected from the Shanghai Pudong Development Bank and Citi Bank strategic alliance. The results are consistent with the model’s descriptive validity.
ContributorsLiu, Xinyi (Author) / Pei, Ker-Wei (Thesis advisor) / Chen, Hong (Committee member) / Shen, Wei (Committee member) / Arizona State University (Publisher)
Created2015
Description
This study investigates the performance effects of cross-industry mergers and acquisitions (M&A) using a sample of firms listed in China’s Growth Entrepreses Market (GEM). Compared to firms listed in the Shanghai and Shenzhen Stock Exchanges, firms listed in the GEM are much smaller and tend to derive the majority of their revenues from a single industry. I first analyze the motives for firms listed in the GEM to engage in M&As and propose a set of factors that may influence their likelihood of M&A activities. Using data on 55 cross-industry M&As between January 1, 2012 and December 31, 2016, I find that investor generally responded positively in short-term, as indicated by the positive accumulated abonormal returns over the first five trading days following the announcements. Meanwhile, I found no evidence that investors benefited from cross-industry M&As in long-term over three years after the event. Further analysis suggests that the short-term effects of cross-industry M&As by GEM listed firms were influenced by the target firm’s market valuation, whether the M&A was paid by cash, the amount of the payment, and the degree of difference between the acquiring firm’s and the target firm’s industries. These findings have important implications for the investors and senior executives of firms listed in the GEM.
ContributorsZhou, Wei (Author) / Shen, Wei (Thesis advisor) / Yu, Xiaoyun (Thesis advisor) / Jiang, Zhan (Committee member) / Arizona State University (Publisher)
Created2018
Description
This thesis aims to investigate the impacts of foreign banks’ management model on their degree of localization and operating efficiency. I decompose their management model into five major factors, including two formative factors and three reflective factors. The two formative factors are (1) strategic orientation and (2) target customers, and the three reflective factors are (1) top management team composition, (2) organizational structure, and (3) managerial authority and incentives. I propose that the formative factors influence foreign banks’ degree of localization, as demonstrated by the reflective factors, which subsequently influence foreign banks’ operating efficiency in China.
To test the above proposition, I conduct the empirical analysis in three steps. In the first step, I investigate foreign banks’ management model by surveying 13 major foreign banks locally incorporated in Mainland China. The results suggest that these 13 foreign banks can be categorized into three distinct groups based on their management model: intergrators, customer-followers, and parent-followers. The results also indicate that intergrators have the highest level of localization while parent-followers have the lowest level of localization.
In the second step, I conduct DEA (Data Envelope Analysis) and CAMEL (Capital Adequacy, Asset Quality, Management, Earnings, Liquidity Analysis) to assess the operating efficiency of these 13 foreign banks. The assessment is conducted in two ways: 1) the inter-group comparison between foreign banks and local Chinese banks; 2) the intra-group comparison between the three distinct groups of foreign banks identified in the first step. The results indicates that the principal factor driving the operating efficiency of both local Chinese banks and foreign banks is the comprehensive technical efficiency, which includes both the quality of management and the quality of technical elements. I also find the uptrend of technical efficiency of the integrators is more stable than that of the other two groups of foreign banks.
Finally, I integrate the results from step one and step two to assess the relevance between foreign banks’ localization level and operating efficiency. I find that foreign banks that score higher in localization tend to have a higher level of operating efficiency. Although this finding is not conclusive about the causal relationship between localization and operating efficiency, it nevertheless suggests that the management model of the higher performing integrators can serve as references for the other foreign banks attempting to enhance their localization and operating efficiency. I also discuss the future trends of development in the banking industry in China and what foreign banks can learn from local Chinese banks to improve their market positions.
To test the above proposition, I conduct the empirical analysis in three steps. In the first step, I investigate foreign banks’ management model by surveying 13 major foreign banks locally incorporated in Mainland China. The results suggest that these 13 foreign banks can be categorized into three distinct groups based on their management model: intergrators, customer-followers, and parent-followers. The results also indicate that intergrators have the highest level of localization while parent-followers have the lowest level of localization.
In the second step, I conduct DEA (Data Envelope Analysis) and CAMEL (Capital Adequacy, Asset Quality, Management, Earnings, Liquidity Analysis) to assess the operating efficiency of these 13 foreign banks. The assessment is conducted in two ways: 1) the inter-group comparison between foreign banks and local Chinese banks; 2) the intra-group comparison between the three distinct groups of foreign banks identified in the first step. The results indicates that the principal factor driving the operating efficiency of both local Chinese banks and foreign banks is the comprehensive technical efficiency, which includes both the quality of management and the quality of technical elements. I also find the uptrend of technical efficiency of the integrators is more stable than that of the other two groups of foreign banks.
Finally, I integrate the results from step one and step two to assess the relevance between foreign banks’ localization level and operating efficiency. I find that foreign banks that score higher in localization tend to have a higher level of operating efficiency. Although this finding is not conclusive about the causal relationship between localization and operating efficiency, it nevertheless suggests that the management model of the higher performing integrators can serve as references for the other foreign banks attempting to enhance their localization and operating efficiency. I also discuss the future trends of development in the banking industry in China and what foreign banks can learn from local Chinese banks to improve their market positions.
ContributorsSun, Minjie (Author) / Shen, Wei (Thesis advisor) / Qian, Jun (Thesis advisor) / Pei, Ker-Wei (Committee member) / Arizona State University (Publisher)
Created2016
Description
This study investigates the impact of a specific organizational form – partnership – on employees’ awareness of risk control and job engagement in securities companies. Given that their organizational performance relies heavily on the performance of individual employees, it is critical for securities companies in China to adopt appropriate organizational forms so that they can better captalize on their employees’ human capital to cope with the increasingly intense market competition. Partnership, as one of the few organizational forms, has been widely adopted in industries that rely on the performance of individuals, such as law, auditing, consulting, and investment banking, around the world. In the context of China’s emerging economy, it has also been adopted as an incentive system by market leaders across several industries, including Alibaba in online shopping, Vanke in real estate, and Fosun in investments. In contrast, partnership has not been adopted or implemented by securities companies in China as most of them are still state-owned enterprises.
Based on my review of the corporate governance literature and qualitative analysis of partnership adoption in China, I propose that partnership can help better alighn the interests of employees with owners in securities companies as well. Specifically, the prospect of becoming a partner in the future can improve employees’ awareness of risk control and increase their job engagement. Taking advantage of partnership adoption at a Chinese securities company as a natural field experienment, I surveyed its employees about their awareness of risk contrl and job dedication before and after the adoption. The results from 505 matched surveys showed an increase in the average scores of both awareness of risk control and job dedication after the company adopted partnership as a new organizational form. Findings of this study have important implications for organizational and incentive design for securities companies in China.
Based on my review of the corporate governance literature and qualitative analysis of partnership adoption in China, I propose that partnership can help better alighn the interests of employees with owners in securities companies as well. Specifically, the prospect of becoming a partner in the future can improve employees’ awareness of risk control and increase their job engagement. Taking advantage of partnership adoption at a Chinese securities company as a natural field experienment, I surveyed its employees about their awareness of risk contrl and job dedication before and after the adoption. The results from 505 matched surveys showed an increase in the average scores of both awareness of risk control and job dedication after the company adopted partnership as a new organizational form. Findings of this study have important implications for organizational and incentive design for securities companies in China.
ContributorsSha, Changming (Author) / Shen, Wei (Thesis advisor) / Li, Feng (Thesis advisor) / Gu, Bin (Committee member) / Arizona State University (Publisher)
Created2018
Description
China's city commercial banks were reorganized by the urban credit cooperatives in the same city in the 1990s. Although they are allowed to open branches outside the registered city, the location and the number of their branches have been strictly restricted. It is fatal to them to increase the competitiveness of their branches. Based on the diversity theory and its mechanism, in this study I examined the impact of source diversity of the senior management in the branches of the city commercial bank on the branches’ productivity and their asset yield. Invoking the resource-based theory and the social capital framework, the source diversity lead to the organization resources diversity and the organization knowledge diversity. The results demonstrate that the source diversity contribute to the branches’ competitiveness advantage. Both internal trained personnel and external introduction personnel are important for the branches’ top management team. But one of the two kinds of personnel is more suitable to their middle management team.
ContributorsZhang, Xiande (Author) / Gu, Bin (Thesis advisor) / Wang, Tan (Thesis advisor) / Shen, Wei (Committee member) / Arizona State University (Publisher)
Created2017
Description
Solar power, as an important part of renewable energy, has become one of the main choices for countries around the world in their energy strategic layout due to its cleanliness, renewability, and distributed attributes. In the context of the booming photovoltaic industry, China has emerged a large number of excellent photovoltaic companies, driving the whole industry to reduce costs and increase efficiency, making many contributions to the grid parity of photovoltaic power generation. In the development lifecycle of the photovoltaic industry, various companies choose different competitive strategies to deal with industry cyclical changes and external uncertainty based on their core competitiveness and market opportunities. Vertical integration is one of the strategic paths chosen by many photovoltaic companies. Therefore, it is an important issue to explore the impact of vertical integration on the development of Chinese photovoltaic companies.Based on the data of China's A-share listed photovoltaic companies from 2018 to 2022, this paper uses panel fixed effect model to empirically test the impact of vertical integration on corporate valuation, explores its influencing mechanism, and further analyzes the moderating effect of enterprise heterogeneity factors. The research in this paper shows that: (1) under other conditions unchanged, vertical integration significantly improves the valuation level of enterprises, and this positive impact will not change with the measurement method of enterprise valuation level. This is because the higher the vertical integration degree of enterprises, the stronger their ability to respond to external uncertainty. The more enterprises can obtain capital market preferences, the higher the enterprise valuation will be. This also means that the higher the vertical integration degree of photovoltaic enterprises, the higher their market share is, and they are more able to avoid the impact of external uncertainty, thus obtaining a higher valuation level in the secondary market. (2) The intermediary effect test shows that the channel for vertical integration of photovoltaic enterprises to affect enterprise valuation levels is to increase their market share. (3) Further heterogeneity analysis shows that enterprise profitability and enterprise size positively regulate the impact of vertical integration on enterprise valuation, while enterprise management shareholding ratio and enterprise operating cost ratio will weaken the positive promotion effect of vertical integration.
The research conclusions of this paper provide micro-empirical evidence for how photovoltaic companies can improve their enterprise valuation, and also provide some management references for other unlisted companies in the same industry.
Keywords: Photovoltaic enterprises; Vertical integration; Corporate valuation; Fixed effect model
ContributorsZheng, Ren (Author) / Shen, Wei (Thesis advisor) / Wu, Fei (Thesis advisor) / Zhao, Yanfei (Committee member) / Arizona State University (Publisher)
Created2024
Description
The field of unmanned aerial vehicle, or UAV, navigation has been moving towards collision inclusive path planning, yet work has not been done to consider what a UAV is colliding with, and if it should or not. Therefore, there is a need for a framework that allows a UAV to consider what is around it and find the best collision candidate. The following work presents a framework that allows UAVs to do so, by considering what an object is and the properties associated with it. Specifically, it considers an object’s material and monetary value to decide if it is good to collide with or not. This information is then published on a binary occupancy map that contains the objects’ size and location with respect to the current position of the UAV. The intent is that the generated binary occupancy map can be used with a path planner to decide what the UAV should collide with. The framework was designed to be as modular as possible and to work with conventional UAV's that have some degree of crash resistance incorporated into their design. The framework was tested by using it to identify various objects that could be collision candidates or not, and then carrying out collisions with some of the objects to test the framework’s accuracy. The purpose of this research was to further the field of collision inclusive path planning by allowing UAVs to know, in a way, what they are intending to collide with and decide if they should or not in order to make safer and more efficient collisions.
ContributorsMolnar, Madelyn Helena (Author) / Zhang, Wenlong (Thesis advisor) / Sugar, Thomas (Committee member) / Guo, Shenghan (Committee member) / Arizona State University (Publisher)
Created2024