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Description
The theme for this work is the development of fast numerical algorithms for sparse optimization as well as their applications in medical imaging and source localization using sensor array processing. Due to the recently proposed theory of Compressive Sensing (CS), the $\ell_1$ minimization problem attracts more attention for its ability to exploit sparsity. Traditional interior point methods encounter difficulties in computation for solving the CS applications. In the first part of this work, a fast algorithm based on the augmented Lagrangian method for solving the large-scale TV-$\ell_1$ regularized inverse problem is proposed. Specifically, by taking advantage of the separable structure, the original problem can be approximated via the sum of a series of simple functions with closed form solutions. A preconditioner for solving the block Toeplitz with Toeplitz block (BTTB) linear system is proposed to accelerate the computation. An in-depth discussion on the rate of convergence and the optimal parameter selection criteria is given. Numerical experiments are used to test the performance and the robustness of the proposed algorithm to a wide range of parameter values. Applications of the algorithm in magnetic resonance (MR) imaging and a comparison with other existing methods are included. The second part of this work is the application of the TV-$\ell_1$ model in source localization using sensor arrays. The array output is reformulated into a sparse waveform via an over-complete basis and study the $\ell_p$-norm properties in detecting the sparsity. An algorithm is proposed for minimizing a non-convex problem. According to the results of numerical experiments, the proposed algorithm with the aid of the $\ell_p$-norm can resolve closely distributed sources with higher accuracy than other existing methods.
ContributorsShen, Wei (Author) / Mittlemann, Hans D (Thesis advisor) / Renaut, Rosemary A. (Committee member) / Jackiewicz, Zdzislaw (Committee member) / Gelb, Anne (Committee member) / Ringhofer, Christian (Committee member) / Arizona State University (Publisher)
Created2011
Description
Recognizing that CEOs are less capable of diversifying their employment risks than shareholders who could diversify their investment risks through portfolio investments, agency theory assumes that CEOs tend to be risk averse compared with shareholders. Based on this assumption, agency theory scholars suggest that to align the risk preference of CEOs with that of shareholders, CEOs need to be closely monitored and have less power. SEC regulators have been adopting the suggestion and accordingly CEO power has been reduced in the past decades. However, the empirical results are mixed and cannot provide solid support for the suggestion that reducing CEO power could lead the CEO to take more risks.
Considering that managerial risk taking is an important issue in strategic management research and agency theory has been widely adopted in academia and business worlds, it is imperative to clarify the mechanism behind the relationship between CEO power and risk taking. My study aims to fill this research gap. In this study I follow agency theory to take an employment security perspective and fully consider how CEOs’ concern about employment security is affected by their power and ownership structure to enrich the understanding of the effects of CEO power and ownership structure on risk taking. I fine-tune the key concept CEO power into the CEO power over board and introduce a key aspect of ownership structure - nontransient investor ownership. I further suggest that CEO power over board and nontransient investor ownership affect CEOs’ employment security and the resulting CEO risk taking. In addition, I consider a set of industry and firm characteristics as the boundary conditions for the effects of CEO power and nontransient investor ownership on CEO risk-taking. This set of industry and firm characteristics include industry complexity, industry dynamism, industry munificence and firm slack.
I test my theory using a large-scale, multi-year sample of U.S. publicly listed S&P 1500 firms between 2001 and 2017. My main hypotheses about the effects of CEO power over board and nontransient investor ownership on CEO risk taking receive strong support.
Considering that managerial risk taking is an important issue in strategic management research and agency theory has been widely adopted in academia and business worlds, it is imperative to clarify the mechanism behind the relationship between CEO power and risk taking. My study aims to fill this research gap. In this study I follow agency theory to take an employment security perspective and fully consider how CEOs’ concern about employment security is affected by their power and ownership structure to enrich the understanding of the effects of CEO power and ownership structure on risk taking. I fine-tune the key concept CEO power into the CEO power over board and introduce a key aspect of ownership structure - nontransient investor ownership. I further suggest that CEO power over board and nontransient investor ownership affect CEOs’ employment security and the resulting CEO risk taking. In addition, I consider a set of industry and firm characteristics as the boundary conditions for the effects of CEO power and nontransient investor ownership on CEO risk-taking. This set of industry and firm characteristics include industry complexity, industry dynamism, industry munificence and firm slack.
I test my theory using a large-scale, multi-year sample of U.S. publicly listed S&P 1500 firms between 2001 and 2017. My main hypotheses about the effects of CEO power over board and nontransient investor ownership on CEO risk taking receive strong support.
ContributorsZhu, Qi (Author) / Shen, Wei (Thesis advisor) / Zhu, David (Thesis advisor) / Certo, Trevis (Committee member) / Arizona State University (Publisher)
Created2019
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
Entrepreneurship entails a transition from status quo to a founder/leader of a new organization, and the dominant view in the literature focuses on opportunities in a hypothetical situation, namely an entrepreneurial option. This study shifts the attention from an entrepreneurial option to a current situation and proposes that a perception of costliness in status quo as a driver of entrepreneurial decisions and strategies. Specifically, I propose that a perception of inequality due to the local hierarchy of an organization engenders motivation of disadvantaged employees to become a leader of his/her own entrepreneurial organization. Utilizing hierarchy-based power dynamics and attribution biases, I theorize that i) status gap between a leader and a member and ii) status distinctiveness of a leader in the current organization affect an entrepreneurial decision because of inequality perception. Furthermore, I hypothesize that entrepreneurial organizations driven by such status inequality are more likely to replicate the local structure of the previous employer in terms of status hierarchy to compensate for the perceived disadvantages in the previous employer. The empirical analyses of this study investigate entrepreneurial decisions and entrepreneurial team formation of jazz musicians from jazz discographies between 1950 and 2018, and I found supportive results. This study contributes to the entrepreneurship and inequality literature by bridging two research spaces. It first uncovers the roles of a negative perception of the status quo in entrepreneurship, in addition to the established idea of a positive perception of an alternative option. It also suggests a novel explanation of the long-standing question of inequality reproduction by looking at whether and how inequality spreads via entrepreneurship.
ContributorsJeon, Chunhu (Author) / Shen, Wei (Thesis advisor) / Bundy, Jonathan N (Thesis advisor) / Certo, S. Trevis (Committee member) / Arizona State University (Publisher)
Created2022
Description
This paper analyzes China's transformative changes over the past four decades through a microeconomic lens focused on enterprises. Market-oriented non-state-owned enterprises have emerged as a pivotal force driving China's economic development within this context. The article investigates the determinants of their development. Notably, more than half of market-oriented non-state-owned enterprises have entered the inheritance stage, necessitating the exploration of novel attributes for sustained growth.The study's research scope is defined across four dimensions, with a specific focus on approximately 4,000 market-oriented non-state-owned enterprises. It investigates the driving factors behind sustained performance growth at various stages of these enterprises, emphasizing five variables: "partnership governance, entrepreneurial spirit, development strategy, incentive mechanisms, and innovation capability." Employing a combination of "typical case studies" and "group validation" methods, the research examines the factors influencing sustained growth in these enterprises and their interrelationships. The goal is to construct a model for enterprise succession and development, ultimately offering recommendations to foster sustained growth.
The research paper is structured into an introduction, literature review and theoretical foundation, typical case studies, empirical research on a group, and a conclusion.
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Key findings include: Partnership governance positively impacts partners' entrepreneurial spirit, promoting sustained performance growth. Trajectory-oriented development strategies, effective incentive mechanisms, and leading innovation capabilities have a positive moderating effect on entrepreneurial spirit, fostering sustained performance growth. During the innovation development phase, partnership governance significantly influences entrepreneurial spirit with a noteworthy environmental moderation effect.
The paper recommends implementing a "Dual-Factor Improvement Model" that enhances both partnership governance systems and the selection and functioning mechanisms of entrepreneurial spirit partners. This approach aims to boost partners' entrepreneurial spirit and facilitate high-quality succession in market-oriented non-state-owned enterprises，，ultimately achieving sustained high-quality growth.
In conclusion, this research contributes to a deeper understanding of sustained performance growth in enterprises. It offers valuable insights for the succession and development of market-oriented non-state-owned enterprises and innovation-driven entrepreneurship. This research holds significant value in advancing sustained high-quality development among market-oriented non-state-owned enterprises in China, optimizing resource allocation, and nurturing talented individuals.
ContributorsDeng, Cheng (Author) / Shen, Wei (Thesis advisor) / Cheng, Shijun (Thesis advisor) / Wu, Fei (Committee member) / Arizona State University (Publisher)
Created2023
Description
With the increasing aging population in China, the public's emphasis on health has been on the rise. Many innovative pharmaceutical companies have undertaken multiple rounds of financing, with some going public through IPOs. As a high-tech industry, it is essential to study the relationship between the level of corporate publicity and the financing process.This study collected information on the number of promotional articles, timing, and platforms of dozens of pharmaceutical companies that have already gone public through IPOs using Python. An analysis was conducted on the temporal variations of promotional articles for ten representative companies. It was found that the number of promotional articles experienced a significant increase in the month of IPO or the month before, and remained relatively high even after the IPO.
Furthermore, the Pearson correlation coefficient method was used to analyze the correlation between the number of promotional articles and various stages of financing. The study found a positive correlation between the daily average number of promotional articles before IPO and the final financing amount. Additionally, a strong positive correlation was observed between the daily average number of promotional articles from 7 days before IPO to IPO day and the turnover rate on IPO day. Grey correlation analysis was also employed to analyze the impact of publicity on the financing amount of each
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financing round, revealing that the financing round and the Shanghai Composite Index had a significant influence.
Finally, a multiple regression analysis was conducted to examine the relationship between the pre-IPO financing scale, IPO-day trading amount, and the level of corporate publicity. The regression results indicated that the pre-IPO financing scale was mainly influenced by the number of promotional articles in the 7 days preceding IPO, particularly for pharmaceutical companies listed on the A-share market. Moreover, a negative correlation was observed between the financing round and the financing amount, particularly among companies that experienced a decline in share price on the IPO day. However, the study found a weak association between the IPO-day trading amount and the level of corporate publicity, primarily observed among pharmaceutical companies listed on the A-share market.
ContributorsMiao, Yujia (Author) / Shen, Wei (Thesis advisor) / Jiang, Zhan (Thesis advisor) / Cheng, Shijun (Committee member) / Arizona State University (Publisher)
Created2024
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