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.
Displaying 41 - 50 of 117
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- Creators: Shen, Wei
- Creators: Tsakalis, Konstantinos
Description
This study seeks to develop a framework that can help firms in China’s guarantee industry to better identify and prevent risk when they offer guarantee services to small and medium-sized enterprises (SME). With the continuously increasing demands of SME financing, the guarantee industry has developed rapidly in China. Meanwhile, the turmoil in global financial markets and the significant slowdown of global economy have started to have a negative impact on China’s economy, increasing the risk exposure of China’s guarantee industry. In this context, risk identification and prevention becomes the core competence of a guarantee company. Based on a review of the existing research, two in-depth case studies, and the author’s personal experiences in this industry, this paper does not only provide a comprehensive list of the risks that guarantee firms face in China but also measures for risk identification and prevention.
This thesis is organized as follows. First, I provide a brief description about the emergence and development of China’s guarantee industry, as well as its current status. Next, I explain what kinds of risks faced by guarantee firms in China that influence their performance and survival, and summarize the various external and internal risk factors. I also conduct one in-depth case analysis to illustrate how a guarantee firm can better identify the risks it is exposed to. Next, on the basis of another in-depth case analysis, I develop a framework that can help guarantee firms to systematically develop effective measures of risk identification and prevention. I conclude with a discussion of this study’s implications for guarantee firms and the regulatory governmental agencies in China.
This thesis is organized as follows. First, I provide a brief description about the emergence and development of China’s guarantee industry, as well as its current status. Next, I explain what kinds of risks faced by guarantee firms in China that influence their performance and survival, and summarize the various external and internal risk factors. I also conduct one in-depth case analysis to illustrate how a guarantee firm can better identify the risks it is exposed to. Next, on the basis of another in-depth case analysis, I develop a framework that can help guarantee firms to systematically develop effective measures of risk identification and prevention. I conclude with a discussion of this study’s implications for guarantee firms and the regulatory governmental agencies in China.
ContributorsWu, Daorong (Author) / Shen, Wei (Thesis advisor) / Liu, Jun (Thesis advisor) / Chang, Chun (Committee member) / Arizona State University (Publisher)
Created2016
Description
Vertical taking off and landing (VTOL) drones started to emerge at the beginning of this century, and finds applications in the vast areas of mapping, rescuing, logistics, etc. Usually a VTOL drone control system design starts from a first principles model. Most of the VTOL drones are in the shape of a quad-rotor which is convenient for dynamic analysis.
In this project, a VTOL drone with shape similar to a Convair XFY-1 is studied and the primary focus is developing and examining an alternative method to identify a system model from the input and output data, with which it is possible to estimate system parameters and compute model uncertainties on discontinuous data sets. We verify the models by designing controllers that stabilize the yaw, pitch, and roll angles for the VTOL drone in the hovering state.
This project comprises of three stages: an open-loop identification to identify the yaw and pitch dynamics, an intermediate closed-loop identification to identify the roll action dynamic and a closed-loop identification to refine the identification of yaw and pitch action. In open and closed loop identifications, the reference signals sent to the servos were recorded as inputs to the system and the angles and angular velocities in yaw and pitch directions read by inertial measurement unit were recorded as outputs of the system. In the intermediate closed loop identification, the difference between the reference signals sent to the motors on the contra-rotators was recorded as input and the roll angular velocity is recorded as output. Next, regressors were formed by using a coprime factor structure and then parameters of the system were estimated using the least square method. Multiplicative and divisive uncertainties were calculated from the data set and were used to guide PID loop-shaping controller design.
In this project, a VTOL drone with shape similar to a Convair XFY-1 is studied and the primary focus is developing and examining an alternative method to identify a system model from the input and output data, with which it is possible to estimate system parameters and compute model uncertainties on discontinuous data sets. We verify the models by designing controllers that stabilize the yaw, pitch, and roll angles for the VTOL drone in the hovering state.
This project comprises of three stages: an open-loop identification to identify the yaw and pitch dynamics, an intermediate closed-loop identification to identify the roll action dynamic and a closed-loop identification to refine the identification of yaw and pitch action. In open and closed loop identifications, the reference signals sent to the servos were recorded as inputs to the system and the angles and angular velocities in yaw and pitch directions read by inertial measurement unit were recorded as outputs of the system. In the intermediate closed loop identification, the difference between the reference signals sent to the motors on the contra-rotators was recorded as input and the roll angular velocity is recorded as output. Next, regressors were formed by using a coprime factor structure and then parameters of the system were estimated using the least square method. Multiplicative and divisive uncertainties were calculated from the data set and were used to guide PID loop-shaping controller design.
ContributorsLiu, Yiqiu (Author) / Tsakalis, Konstantinos (Thesis advisor) / Rodriguez, Armando (Thesis advisor) / Rivera, Daniel (Committee member) / Arizona State University (Publisher)
Created2015
Description
Informal finance in this paper refers to the financing activities of individuals or households to borrow money through channels other than formal financial institutions such as commercial banks. Using data from China Household Finance Survey (CHFS) conducted by Southwestern University of Finance and Economics (SWUFE) and the People's Bank of China, this paper employs Probit model to analyze the factors that may influence the financing needs of Chinese households and factors that influence their likelihood of obtaining loans from formal financial institutions versus from informal channels. Results show that household wealth, family structure, and household head’s characteristics are the major factors that influence their financing needs. Moreover, the results suggest that (a) richer families are more likely to obtain loans from formal financial channels while poorer families are more likely to do so from informal channels; (b) families with stronger social ties are more likely to obtain loans from formal financial channels, but this relationship is weaker in regions where the financial market is more competitive;and (c) the increase of formal financial services is positively related to the probability of households obtaining formal finance, but has no relationship with the probability of households obtaining informal finance. These findings have important implications for finance policy making.
ContributorsZhang, Linchao (Author) / Shen, Wei (Thesis advisor) / Chen, Xiaoping (Thesis advisor) / Liu, Jun (Committee member) / Arizona State University (Publisher)
Created2016
Description
This thesis investigates whether mergers and acquisitions (M&As) help increase the competitive advantage and core competency of Chinese securities companies. Although M&As among Chinese securities companies were almost exclusively guided by the Chinese government in the earlier years, they have increasingly become more market-driven in recent years. Many large Chinese securities companies have engaged in horizontal mergers, cross-industry mergers, and cross-border mergers to increase their market positions. However, there is little up-to-date evidence about how these market-driven M&As influence the competitive advantage and core competency of securities companies in China. I seek to fill this gap by conducting a systematic analysis about whether M&As increase the core competency of the acquiring companies using data collected over a five-year window from 2010 to 2014.
On the basis of prior research findings and the current situation of the Chinese securities industry, I first develop a theoretical model about the sources of competitive advantage for Chinese securities companies, and then compile a comprehensive list of observable indicators that can be used to assess a Chinese securities company’s core competency. Next, I conduct a quantitative analysis to assess the core competency and relative market positions of the leading Chinese securities companies using data from 2010 to 2014. Overall, the results suggest that market-driven M&As increases the core competency of the acquiring securities companies. I then conduct four in-depth case analyses to better understand the mechanisms through which M&As can help increase the acquiring firms' core competency. I conclude with a discussion of the findings and their implications for Chinese securities companies and the overseeing governmental agencies.
On the basis of prior research findings and the current situation of the Chinese securities industry, I first develop a theoretical model about the sources of competitive advantage for Chinese securities companies, and then compile a comprehensive list of observable indicators that can be used to assess a Chinese securities company’s core competency. Next, I conduct a quantitative analysis to assess the core competency and relative market positions of the leading Chinese securities companies using data from 2010 to 2014. Overall, the results suggest that market-driven M&As increases the core competency of the acquiring securities companies. I then conduct four in-depth case analyses to better understand the mechanisms through which M&As can help increase the acquiring firms' core competency. I conclude with a discussion of the findings and their implications for Chinese securities companies and the overseeing governmental agencies.
ContributorsWang, Lijuan (Author) / Shen, Wei (Thesis advisor) / Qian, Jun (Thesis advisor) / Liu, Jun (Committee member) / Arizona State University (Publisher)
Created2016
Description
Buck converters are electronic devices that changes a voltage from one level to a lower one and are present in many everyday applications. However, due to factors like aging, degradation or failures, these devices require a system identification process to track and diagnose their parameters. The system identification process should be performed on-line to not affect the normal operation of the device. Identifying the parameters of the system is essential to design and tune an adaptive proportional-integral-derivative (PID) controller.
Three techniques were used to design the PID controller. Phase and gain margin still prevails as one of the easiest methods to design controllers. Pole-zero cancellation is another technique which is based on pole-placement. However, although these controllers can be easily designed, they did not provide the best response compared to the Frequency Loop Shaping (FLS) technique. Therefore, since FLS showed to have a better frequency and time responses compared to the other two controllers, it was selected to perform the adaptation of the system.
An on-line system identification process was performed for the buck converter using indirect adaptation and the least square algorithm. The estimation error and the parameter error were computed to determine the rate of convergence of the system. The indirect adaptation required about 2000 points to converge to the true parameters prior designing the controller. These results were compared to the adaptation executed using robust stability condition (RSC) and a switching controller. Two different scenarios were studied consisting of five plants that defined the percentage of deterioration of the capacitor and inductor within the buck converter. The switching logic did not always select the optimal controller for the first scenario because the frequency response of the different plants was not significantly different. However, the second scenario consisted of plants with more noticeable different frequency responses and the switching logic selected the optimal controller all the time in about 500 points. Additionally, a disturbance was introduced at the plant input to observe its effect in the switching controller. However, for reasonable low disturbances no change was detected in the proper selection of controllers.
Three techniques were used to design the PID controller. Phase and gain margin still prevails as one of the easiest methods to design controllers. Pole-zero cancellation is another technique which is based on pole-placement. However, although these controllers can be easily designed, they did not provide the best response compared to the Frequency Loop Shaping (FLS) technique. Therefore, since FLS showed to have a better frequency and time responses compared to the other two controllers, it was selected to perform the adaptation of the system.
An on-line system identification process was performed for the buck converter using indirect adaptation and the least square algorithm. The estimation error and the parameter error were computed to determine the rate of convergence of the system. The indirect adaptation required about 2000 points to converge to the true parameters prior designing the controller. These results were compared to the adaptation executed using robust stability condition (RSC) and a switching controller. Two different scenarios were studied consisting of five plants that defined the percentage of deterioration of the capacitor and inductor within the buck converter. The switching logic did not always select the optimal controller for the first scenario because the frequency response of the different plants was not significantly different. However, the second scenario consisted of plants with more noticeable different frequency responses and the switching logic selected the optimal controller all the time in about 500 points. Additionally, a disturbance was introduced at the plant input to observe its effect in the switching controller. However, for reasonable low disturbances no change was detected in the proper selection of controllers.
ContributorsSerrano Rodriguez, Victoria Melissa (Author) / Tsakalis, Konstantinos (Thesis advisor) / Bakkaloglu, Bertan (Thesis advisor) / Rodriguez, Armando (Committee member) / Spanias, Andreas (Committee member) / Arizona State University (Publisher)
Created2016
Description
For a sensor array, part of its elements may fail to work due to hardware failures. Then the missing data may distort in the beam pattern or decrease the accuracy of direction-of-arrival (DOA) estimation. Therefore, considerable research has been conducted to develop algorithms that can estimate the missing signal information. On the other hand, through those algorithms, array elements can also be selectively turned off while the missed information can be successfully recovered, which will save power consumption and hardware cost.
Conventional approaches focusing on array element failures are mainly based on interpolation or sequential learning algorithm. Both of them rely heavily on some prior knowledge such as the information of the failures or a training dataset without missing data. In addition, since most of the existing approaches are developed for DOA estimation, their recovery target is usually the co-variance matrix but not the signal matrix.
In this thesis, a new signal recovery method based on matrix completion (MC) theory is introduced. It aims to directly refill the absent entries in the signal matrix without any prior knowledge. We proposed a novel overlapping reshaping method to satisfy the applying conditions of MC algorithms. Compared to other existing MC based approaches, our proposed method can provide us higher probability of successful recovery. The thesis describes the principle of the algorithms and analyzes the performance of this method. A few application examples with simulation results are also provided.
Conventional approaches focusing on array element failures are mainly based on interpolation or sequential learning algorithm. Both of them rely heavily on some prior knowledge such as the information of the failures or a training dataset without missing data. In addition, since most of the existing approaches are developed for DOA estimation, their recovery target is usually the co-variance matrix but not the signal matrix.
In this thesis, a new signal recovery method based on matrix completion (MC) theory is introduced. It aims to directly refill the absent entries in the signal matrix without any prior knowledge. We proposed a novel overlapping reshaping method to satisfy the applying conditions of MC algorithms. Compared to other existing MC based approaches, our proposed method can provide us higher probability of successful recovery. The thesis describes the principle of the algorithms and analyzes the performance of this method. A few application examples with simulation results are also provided.
ContributorsFan, Jie (Author) / Spanias, Andreas (Thesis advisor) / Tepedelenlioğlu, Cihan (Committee member) / Tsakalis, Konstantinos (Committee member) / Arizona State University (Publisher)
Created2016
Description
From time immemorial, epilepsy has persisted to be one of the greatest impediments to human life for those stricken by it. As the fourth most common neurological disorder, epilepsy causes paroxysmal electrical discharges in the brain that manifest as seizures. Seizures have the effect of debilitating patients on a physical and psychological level. Although not lethal by themselves, they can bring about total disruption in consciousness which can, in hazardous conditions, lead to fatality. Roughly 1\% of the world population suffer from epilepsy and another 30 to 50 new cases per 100,000 increase the number of affected annually. Controlling seizures in epileptic patients has therefore become a great medical and, in recent years, engineering challenge.
In this study, the conditions of human seizures are recreated in an animal model of temporal lobe epilepsy. The rodents used in this study are chemically induced to become chronically epileptic. Their Electroencephalogram (EEG) data is then recorded and analyzed to detect and predict seizures; with the ultimate goal being the control and complete suppression of seizures.
Two methods, the maximum Lyapunov exponent and the Generalized Partial Directed Coherence (GPDC), are applied on EEG data to extract meaningful information. Their effectiveness have been reported in the literature for the purpose of prediction of seizures and seizure focus localization. This study integrates these measures, through some modifications, to robustly detect seizures and separately find precursors to them and in consequence provide stimulation to the epileptic brain of rats in order to suppress seizures. Additionally open-loop stimulation with biphasic currents of various pairs of sites in differing lengths of time have helped us create control efficacy maps. While GPDC tells us about the possible location of the focus, control efficacy maps tells us how effective stimulating a certain pair of sites will be.
The results from computations performed on the data are presented and the feasibility of the control problem is discussed. The results show a new reliable means of seizure detection even in the presence of artifacts in the data. The seizure precursors provide a means of prediction, in the order of tens of minutes, prior to seizures. Closed loop stimulation experiments based on these precursors and control efficacy maps on the epileptic animals show a maximum reduction of seizure frequency by 24.26\% in one animal and reduction of length of seizures by 51.77\% in another. Thus, through this study it was shown that the implementation of the methods can ameliorate seizures in an epileptic patient. It is expected that the new knowledge and experimental techniques will provide a guide for future research in an effort to ultimately eliminate seizures in epileptic patients.
In this study, the conditions of human seizures are recreated in an animal model of temporal lobe epilepsy. The rodents used in this study are chemically induced to become chronically epileptic. Their Electroencephalogram (EEG) data is then recorded and analyzed to detect and predict seizures; with the ultimate goal being the control and complete suppression of seizures.
Two methods, the maximum Lyapunov exponent and the Generalized Partial Directed Coherence (GPDC), are applied on EEG data to extract meaningful information. Their effectiveness have been reported in the literature for the purpose of prediction of seizures and seizure focus localization. This study integrates these measures, through some modifications, to robustly detect seizures and separately find precursors to them and in consequence provide stimulation to the epileptic brain of rats in order to suppress seizures. Additionally open-loop stimulation with biphasic currents of various pairs of sites in differing lengths of time have helped us create control efficacy maps. While GPDC tells us about the possible location of the focus, control efficacy maps tells us how effective stimulating a certain pair of sites will be.
The results from computations performed on the data are presented and the feasibility of the control problem is discussed. The results show a new reliable means of seizure detection even in the presence of artifacts in the data. The seizure precursors provide a means of prediction, in the order of tens of minutes, prior to seizures. Closed loop stimulation experiments based on these precursors and control efficacy maps on the epileptic animals show a maximum reduction of seizure frequency by 24.26\% in one animal and reduction of length of seizures by 51.77\% in another. Thus, through this study it was shown that the implementation of the methods can ameliorate seizures in an epileptic patient. It is expected that the new knowledge and experimental techniques will provide a guide for future research in an effort to ultimately eliminate seizures in epileptic patients.
ContributorsShafique, Md Ashfaque Bin (Author) / Tsakalis, Konstantinos (Thesis advisor) / Rodriguez, Armando (Committee member) / Muthuswamy, Jitendran (Committee member) / Spanias, Andreas (Committee member) / Arizona State University (Publisher)
Created2016
Description
University graduates play a significant role in the labor market of China. Universities continuously supply senior talents and provide a strong guarantee to the country’s development. However, with the enlargement of the enrollment scale, more and more graduates become unemployed or forced to be employed. Most literatures mainly focus on the unemployed phenomenon or reasons, but had neglected the relationship among the employment, universities and the labor market. This assay is trying to using the supply and demand theory of classical economics to analyze the training direction and model of university from the perspective of the supply and demand of labor market. This assay proposes that universities have to integrate with the demand of the labor market so that to cultivate the talents to meet the social needs.
Firstly, the essay analyzes the relationship between the universities education and the supply and demand labor market by using the view of labor economics, and shows the mainly phenomenon and features of supply-demand imbalance. And then, the writer considered that universities talent cultivation development of China has gone through “absolute shortage”, “relative shortage” and “structural unbalanced” three stages. Thirdly, the survey results confirmed that the talent cultivation in universities does not match the demand of the labor market. On one other hand, over educated is a common phenomenon in the academic education. On the other hand, the graduates are lack of education skills training. Fourthly, the essay analyzes the reasons which lead to the unbalance. The unbalance is not only affected by the macro factors, but also by the micro factors. Fifthly, build up the interaction system model “UPT-LM” for the universities talent cultivation and the labor market, and separately building up the macro interaction system and the micro interaction system to analyze the balance of supply and demand. Based on this, it should strengthen the interaction on the feedback mechanism. At last, strengthening the connection of universities talent cultivation and labor market is a systematic program which needs the corporation from the government, the universities and the labor market.
Firstly, the essay analyzes the relationship between the universities education and the supply and demand labor market by using the view of labor economics, and shows the mainly phenomenon and features of supply-demand imbalance. And then, the writer considered that universities talent cultivation development of China has gone through “absolute shortage”, “relative shortage” and “structural unbalanced” three stages. Thirdly, the survey results confirmed that the talent cultivation in universities does not match the demand of the labor market. On one other hand, over educated is a common phenomenon in the academic education. On the other hand, the graduates are lack of education skills training. Fourthly, the essay analyzes the reasons which lead to the unbalance. The unbalance is not only affected by the macro factors, but also by the micro factors. Fifthly, build up the interaction system model “UPT-LM” for the universities talent cultivation and the labor market, and separately building up the macro interaction system and the micro interaction system to analyze the balance of supply and demand. Based on this, it should strengthen the interaction on the feedback mechanism. At last, strengthening the connection of universities talent cultivation and labor market is a systematic program which needs the corporation from the government, the universities and the labor market.
ContributorsLin, Xiaoya (Author) / Shen, Wei (Thesis advisor) / Qian, Jun (Thesis advisor) / Li, Feng (Committee member) / Arizona State University (Publisher)
Created2017
Description
After the 2008 financial crisis, along with information technology and its application
innovation into the burst period, Shared faster economic growth, and then entered into a
rapid expansion in 2014, quickly penetrate into many areas and market segments.
As the securities industry practitioners and Internet financial practitioners, I am
very concerned about sharing economic model in the development of securities
investment niche. As the Internet and mobile penetration rate rise in recent years, the
Internet financial in the rapid development of our country, investors get used for
investment decision-making information via the Internet. Internet social investment
sharing platform based on knowledge sharing and rapid development, has formed
"opinion leaders", "combined with", "automated financial innovation model". The
emergence of these new patterns, provide investors with investment of knowledge sharing,
the investors behavior changes, many small and medium-sized investors into social
sharing platform for the combination of investment talent information and follow orders,
and centered on investment talent view form fan interaction.
This article around the "Shared economic environment on the impact of portfolio
share on investor behavior research," the theme, the relevant literature and resources, and
to detect Shared economic environment provided by the social share portfolio, whether to
change the traditional information decision and disadvantages of small and medium-sized
investors, whether really improved the small and medium-sized investors return on
investment, its conclusion try to explain the traditional period research literature on active
investment and passive investment, the relevant conclusions of small and medium-sized
investors and institutional investors, sharing in the Internet the rapid development of
economic period is changed.
innovation into the burst period, Shared faster economic growth, and then entered into a
rapid expansion in 2014, quickly penetrate into many areas and market segments.
As the securities industry practitioners and Internet financial practitioners, I am
very concerned about sharing economic model in the development of securities
investment niche. As the Internet and mobile penetration rate rise in recent years, the
Internet financial in the rapid development of our country, investors get used for
investment decision-making information via the Internet. Internet social investment
sharing platform based on knowledge sharing and rapid development, has formed
"opinion leaders", "combined with", "automated financial innovation model". The
emergence of these new patterns, provide investors with investment of knowledge sharing,
the investors behavior changes, many small and medium-sized investors into social
sharing platform for the combination of investment talent information and follow orders,
and centered on investment talent view form fan interaction.
This article around the "Shared economic environment on the impact of portfolio
share on investor behavior research," the theme, the relevant literature and resources, and
to detect Shared economic environment provided by the social share portfolio, whether to
change the traditional information decision and disadvantages of small and medium-sized
investors, whether really improved the small and medium-sized investors return on
investment, its conclusion try to explain the traditional period research literature on active
investment and passive investment, the relevant conclusions of small and medium-sized
investors and institutional investors, sharing in the Internet the rapid development of
economic period is changed.
ContributorsMa, Gang (Author) / Gu, Bin (Thesis advisor) / Yan, Hong (Thesis advisor) / Shen, Wei (Committee member) / Arizona State University (Publisher)
Created2017
Description
This thesis examines themodeling, analysis, and control system design issues for scramjet powered hypersonic vehicles. A nonlinear three degrees of freedom longitudinal model which includes aero-propulsion-elasticity effects was used for all analyses. This model is based upon classical compressible flow and Euler-Bernouli structural concepts. Higher fidelity computational fluid dynamics and finite element methods are needed for more precise intermediate and final evaluations. The methods presented within this thesis were shown to be useful for guiding initial control relevant design. The model was used to examine the vehicle's static and dynamic characteristics over the vehicle's trimmable region. The vehicle has significant longitudinal coupling between the fuel equivalency ratio (FER) and the flight path angle (FPA). For control system design, a two-input two-output plant (FER - elevator to speed-FPA) with 11 states (including 3 flexible modes) was used. Velocity, FPA, and pitch were assumed to be available for feedback. Aerodynamic heat modeling and design for the assumed TPS was incorporated to original Bolender's model to study the change in static and dynamic properties. De-centralized control stability, feasibility and limitations issues were dealt with the change in TPS elasticity, mass and physical dimension. The impact of elasticity due to TPS mass, TPS physical dimension as well as prolonged heating was also analyzed to understand performance limitations of de-centralized control designed for nominal model.
ContributorsKhatri, Jaidev (Author) / Rodriguez, Armando Antonio (Thesis advisor) / Tsakalis, Konstantinos (Committee member) / Wells, Valana (Committee member) / Arizona State University (Publisher)
Created2011