Matching Items (12,530)
Filtering by

Clear all filters

161790-Thumbnail Image.png
Description
The seminal work of Lasry and Lion showed the existence of Nash equilibria in thecontinuum limit of agents who try to optimize their own utility functions. However, a lot of work in this region is predicated on strong assumptions on the asymptotic independence of the agents and their homogeneity. This work explores

The seminal work of Lasry and Lion showed the existence of Nash equilibria in thecontinuum limit of agents who try to optimize their own utility functions. However, a lot of work in this region is predicated on strong assumptions on the asymptotic independence of the agents and their homogeneity. This work explores the existence of Equilibria under the limit for Markov Decision Processes for density dependent continuous time Markov chains. Under suitable conditions it is possible to show that the empirical measure of the agents converges in finite time to a time invariant distribution which makes the solution of the MDP tractable. This key step allows one to show not only the existence of equilibria for these MDPs without asymptotic independence but also a tractable means to find said equilibria. Finally, this work shows that a fixed point does exist in the in finite state limit. However, to show that such a limit is indeed a Nash equilibrium remains an open problem.
ContributorsNarasimha, Dheeraj (Author) / Ying, Lei (Thesis advisor) / Dasarathy, Gautam (Thesis advisor) / Liu, Yongmin (Committee member) / Shakkottai, Srinivas (Committee member) / Arizona State University (Publisher)
Created2021
161791-Thumbnail Image.png
Description
In order to perceive the heaviness of an object, one must wield it. This requires muscle activity and its resulting movements. Research has shown that muscle activity and movement combine for this perception in a manner inspired by Newton’s 2nd Law of Motion. Research in this area

In order to perceive the heaviness of an object, one must wield it. This requires muscle activity and its resulting movements. Research has shown that muscle activity and movement combine for this perception in a manner inspired by Newton’s 2nd Law of Motion. Research in this area has relied on specific movement and muscle activity measures that often capture one moment of a lift. The current set of experiments set out to determine which measures best capture the underlying phenomena that lead to heaviness perception during a lift. In the first experiment, participants lifted stimuli with an elbow flexion lift while their muscle activity and movement were recorded. Participants reported their perceived heaviness of the stimuli as soon as they reached it, which resulted in an average decision angle of around 30-degrees. In the second and third experiments, participants the same stimuli with the same elbow flexion lift in four perturbation conditions – they experienced perturbations at 15-degrees of the lift, 30-degrees, 45-degrees, and with no perturbation. In the second experiment, participants experienced a physical perturbation and a cognitive perturbation in the third experiment. Across Experiments 2 and 3, the pattern of results suggested that the more time participants have in a lift, the more proportion correct, muscle activity, and movement measures appears like they do in the no perturbation condition. Additionally, a logistic least absolute shrinkage and selection operator (LASSO) regression was used to determine which measures best predicted perception. Results show that the integrated electromyogram of the biceps brachii that occurs after peak acceleration (iEMG BB after pACC) and Average Acceleration, which are both measures that capture more than one point of a lift, predicted heaviness perception. A new model of heaviness perception was then developed, using these new measures. Comparing this New Model to an Original Model from Waddell et al., 2016 resulted in better prediction from the New Model – suggesting that measure that capture more of a lift better predict heaviness perception, meaning that an entire ongoing action event is important for perception.
ContributorsWaddell, Morgan Leigh (Author) / Amazeen, Eric L (Thesis advisor) / Amazeen, Polemnia G (Committee member) / Glenberg, Arthur M (Committee member) / Gray, Rob (Committee member) / Arizona State University (Publisher)
Created2021
161792-Thumbnail Image.png
Description
Various activities move online in the era of the digital economy. Platform design and policy can heavily affect online user activities and result in many expected and unexpected consequences. In this dissertation, I conduct empirical studies on three types of online platforms to investigate the influence of their platform policy

Various activities move online in the era of the digital economy. Platform design and policy can heavily affect online user activities and result in many expected and unexpected consequences. In this dissertation, I conduct empirical studies on three types of online platforms to investigate the influence of their platform policy on their user engagement and associated outcomes. Specifically, in Study 1, I focus on goal-directed platforms and study how the introduction of the mobile channel affects users’ goal pursuit engagement and persistence. In Study 2, I focus on social media and online communities. I study the introduction of machine-powered platform regulation and its impacts on volunteer moderators’ engagement. In Study 3, I focus on online political discourse forums and examine the role of identity declaration in user participation and polarization in the subsequent political discourse. Overall, my results highlight how various platform policies shape user behavior. Implications on multi-channel adoption, human-machine collaborative platform governance, and online political polarization research are discussed.
ContributorsHe, Qinglai (Author) / Santanam, Raghu (Thesis advisor) / Hong, Yili (Thesis advisor) / Burtch, Gordon (Committee member) / Arizona State University (Publisher)
Created2021
161793-Thumbnail Image.png
Description
Spatial and temporal patterns of biodiversity are shaped, in part, by the resources available to biota, the efficiency of resource transfer through the food web, and variation in environmental conditions. Stream and riparian zones are dynamic systems connected through reciprocal resource exchange and shaped by floods, droughts, and long-term patterns

Spatial and temporal patterns of biodiversity are shaped, in part, by the resources available to biota, the efficiency of resource transfer through the food web, and variation in environmental conditions. Stream and riparian zones are dynamic systems connected through reciprocal resource exchange and shaped by floods, droughts, and long-term patterns in the quantity, timing, and variability of streamflow (flow regime). The interdependent nature of the stream-riparian ecosystem defies the scope of any single discipline, requiring novel approaches to untangle the controls on ecological processes. In this dissertation, I explored multiple mechanisms through which streamflow and energy flow pathways maintain the community and trophic dynamics of desert stream and riparian food webs. I conducted seasonal sampling of Arizona streams on a gradient of flow regime variability to capture fluctuations in aquatic communities and ecosystem production. I found that flow regime shapes fish community structure and the trajectory of community response following short-term flow events by constraining the life history traits of communities, which fluctuate in prevalence following discrete events. Streamflow may additionally constrain the efficiency of energy flow from primary producers to consumers. I estimated annual food web efficiency and found that efficiency decreased with higher temperature and more variable flow regime. Surprisingly, fish production was not related to the rate of aquatic primary production. To understand the origin of resources supporting aquatic and riparian food webs, I studied the contribution of aquatic and terrestrial primary production to consumers in both habitats. I demonstrated that emergent insects “recycled” terrestrial primary production back to the riparian zone, reducing the proportion of aquatic primary production in emergent insect biomass and riparian predator diet. To expand the concept of stream and riparian zones as an integrated ecosystem connected by resource cycling through the food web, I introduced a quantitative framework describing reciprocal interconnections across spatial boundaries and demonstrated strong aquatic-riparian interdependencies along an Arizona river. In this dissertation, I develop a novel perspective on the stream-riparian ecosystem as an intertwined food web, which may be vulnerable to unforeseen impacts of global change if not considered in the context of streamflow and resource dynamics.
ContributorsBaruch, Ethan Max (Author) / Sabo, John (Thesis advisor) / Bateman, Heather (Committee member) / Cease, Arianne (Committee member) / Grimm, Nancy (Committee member) / Arizona State University (Publisher)
Created2021
161794-Thumbnail Image.png
Description
Through an interdisciplinary American Studies approach, this thesis examines access to education and immigrant “illegality” as tools of racial domination by investigating colonial legacies and structural inequalities linked with immigration policy. Providing a background on the political formation of immigrant “illegality”, this research focuses on how race relations have influenced

Through an interdisciplinary American Studies approach, this thesis examines access to education and immigrant “illegality” as tools of racial domination by investigating colonial legacies and structural inequalities linked with immigration policy. Providing a background on the political formation of immigrant “illegality”, this research focuses on how race relations have influenced immigration policies, as well as political efforts to exclude racialized and minoritized groups from lawful immigration, naturalization, and national belonging. These historic texts shed light on overarching connections between the racialized policy construction of immigrant “illegality” and the role of education in nation building and class conservation. Comprising three analytic chapters; the first historicizes how education was used as a tool of the nation-state in the early formation of U.S. territories, the second chapter applies discourse analysis to link contemporary political rhetoric with color-blind ideologies. The third analytic chapter is a critical review of existing quantitative findings on the effects of legal status on educational attainment for Mexican and Central American immigrants and their descendants living in the United States. Challenging the dominant narrative around immigrant “illegality”, this work highlights the racist formation and continued application of unequal access (to both education and citizenship), further demonstrating how structural inequalities remain racialized.
ContributorsOlsen-Medina, Kira (Author) / Yellow Horse, Aggie (Thesis advisor) / Vega, Sujey (Committee member) / Diaz McConnell, Eileen (Committee member) / Arizona State University (Publisher)
Created2021
161795-Thumbnail Image.png
Description

This dissertation explores the representation of female imagery associated with the Yuan pleasure quarters by examining a reservoir of Yuan sanqu. Previous scholarship has studied this topic using either historical material or zaju drama texts but has more or less ignored the voluminous corpus of sanqu. Furthermore, scholarly inquiries of

This dissertation explores the representation of female imagery associated with the Yuan pleasure quarters by examining a reservoir of Yuan sanqu. Previous scholarship has studied this topic using either historical material or zaju drama texts but has more or less ignored the voluminous corpus of sanqu. Furthermore, scholarly inquiries of Yuan sanqu either have emphasized its development from the Song ci lyrical tradition or its colloquial features. In consequence, the complexity of sanqu as an independent literary genre has been neglected. Using the representation of female imagery of the pleasure quarters in Yuan sanqu as an entry point, on one hand, this dissertation examines the dynamics of this urban and textual space. On the other, it focuses on rarely-studied sanqu pieces and analyzes them in a new light. The pleasure quarters and the production of Yuan sanqu are closely related to each other. In particular, the pleasure quarters are both revealed through the creative process of sanqu and have established sanqu as a distinctive aesthetic experience. The first chapter will focus on women of the pleasure quarters from the perspective of their hierarchical distinctions in terms of beauty, performative nature, and desirability as companions. Chapter two discusses the representation of women of the pleasure quarters in Yuan sanqu. Distinctive from the exclusive focus on privileged outstanding courtesans in poetic and lyrical tradition, Yuan sanqu depicted women from different registers of pleasure quarters. Thus, the genre formulated a diverse picture of images, rhetoric, and modalities. Chapter three examines a major literary tradition mainly sustained by the Yuan sanqu tradition, which is the story of Shuang Jian and Su Xiaoqing. As one of the most important and widespread literary traditions at play during the Yuan, Yuan sanqu writers’ representation of this pleasure-quarters-based story manifests the fulness and diversity of Yuan sanqu as a distinctive literary genre. In the epilogue, I focus on a zaju script by Ma Zhiyuan and an anonymous song suite in relation to this story. By so doing, I intend to show how Yuan qu lyrics incorporated the poetic, lyrical, and dramatic traditions in a somewhat promiscuous way.

ContributorsChen, Tianjun (Author) / West, Stephen H (Thesis advisor) / Ling, Xiaoqiao (Thesis advisor) / Oh, Young (Committee member) / Brown, Claudia (Committee member) / Arizona State University (Publisher)
Created2021
161796-Thumbnail Image.png
Description
Sexual minorities use social media platforms at higher rates than heterosexual individuals, often to find and connect with other sexual minorities and the broader online LGBTQ+ community. These online connections may help normalize feelings and experiences as a sexual minority in a heterosexual-normed society by increasing exposure to more meaningful

Sexual minorities use social media platforms at higher rates than heterosexual individuals, often to find and connect with other sexual minorities and the broader online LGBTQ+ community. These online connections may help normalize feelings and experiences as a sexual minority in a heterosexual-normed society by increasing exposure to more meaningful reference groups and helping to mitigate the negative impact of heterosexist norms. There has been relatively little research investigating online social connectedness (OSC) among sexual minority adults, the relation between OSC and positive psychological outcomes, and the role of OSC in lessening the impact of heterosexist norms. The goal of the present thesis was to examine the relation between OSC and positive psychological outcomes, and whether such a relation is mediated by compulsory heterosexuality (CH; i.e., heterosexist norms) and internalized heterosexism (IH; i.e., internalizing and accepting heterosexist norms). A sample of 298 sexual minority adults in the U.S. completed an online survey that included measures of OSC, CH, IH, and positive psychological outcomes including resilience, well-being, self-acceptance, and self-esteem. The hypothesized model, with CH and IH as serial mediators of the relation between OSC and positive psychological outcomes, along with a series of alternative models, were tested using structural equation modeling. Support was found for the hypothesized model, such that greater OSC predicted lower CH, which then predicted lower IH, which in turn predicted greater positive psychological outcomes. While several alternative models had adequate fit, the hypothesized model was best supported statistically and by previous literature. These findings provide insights into the psychological benefits of social media connections for sexual minorities and the potential for OSC to lessen the impact of heterosexist norms. This study also adds to the existing literature regarding OSC and sexual minority adults, expanding the literature from primarily focusing on sexual minority youth. Future studies should be more socio-demographically diverse and longitudinal in nature in order to help better understand the directionality of the relationship between CH and IH. The present findings may also inform the development of interventions aimed at decreasing CH and IH, which future studies should investigate more fully.
ContributorsBaumel, Katie (Author) / Hall, Deborah (Thesis advisor) / Mickelson, Kristin (Committee member) / Salerno, Jessica (Committee member) / Arizona State University (Publisher)
Created2021
161797-Thumbnail Image.png
Description
This dissertation aims to study the electron and spin transport, scattering in two dimensional pseudospin-1 lattice systems, hybrid systems of topological insulator and magnetic insulators, and molecule chain systems. For pseudospin-1 systems, the energy band consists of a pair of Dirac cones and a flat band through the connecting point

This dissertation aims to study the electron and spin transport, scattering in two dimensional pseudospin-1 lattice systems, hybrid systems of topological insulator and magnetic insulators, and molecule chain systems. For pseudospin-1 systems, the energy band consists of a pair of Dirac cones and a flat band through the connecting point of the cones. First, contrary to the conditional wisdom that flatband can localize electrons, I find that in a non-equilibrium situation where a constant electric field is suddenly switched on, the flat band can enhance the resulting current in both the linear and nonlinear response regimes compared to spin-1/2 system. Second, in the setup of massive pseudospin-1 electron scattering over a gate potential scatterer, I discover the large resonant skew scattering called super skew scattering, which does not arise in the corresponding spin-1/2 system and massless pseudospin-1 system. Third, by applying an appropriate gate voltage to generate a cavity in an alpha-T3 lattice, I find the exponential decay of the quasiparticles from a chaotic cavity, with a one-to-one correspondence between the exponential decay rate and the Berry phase for the entire family of alpha-T3 materials. Based on the hybrid system of a ferromagnetic insulator on top of a topological insulator, I first investigate the magnetization dynamics of a pair of ferromagnetic insulators deposited on the surface of a topological insulator. The spin polarized current on the surface of topological insulator can affect the magnetization of the two ferromagnetic insulators through proximity effect, which in turn modulates the electron transport, giving rise to the robust phase locking between the two magnetization dynamics. Second, by putting a skyrmion structure on top of a topological insulator, I find robust electron skew scattering against skyrmion structure even with deformation, due to the emergence of resonant modes. The chirality of molecule can lead to spin polarized transport due to the spin orbit interaction. I investigate spin transport through a chiral polyacetylene molecule and uncover the emergence of spin Fano resonances as a manifestation of the chiral induced spin selectivity effect.
ContributorsWang, Chengzhen (Author) / Lai, Ying-Cheng (Thesis advisor) / Yu, Hongbin (Committee member) / Wang, Chao (Committee member) / Zhao, Yuji (Committee member) / Arizona State University (Publisher)
Created2021
161798-Thumbnail Image.png
Description
Computational social choice theory is an emerging research area that studies the computational aspects of decision-making. It continues to be relevant in modern society because many people often work as a group and make decisions in a group setting. Among multiple research topics, rank aggregation is a central problem in

Computational social choice theory is an emerging research area that studies the computational aspects of decision-making. It continues to be relevant in modern society because many people often work as a group and make decisions in a group setting. Among multiple research topics, rank aggregation is a central problem in computational social choice theory. Oftentimes, rankings may involve a large number of alternatives, contain ties, and/or be incomplete, all of which complicate the use of robust aggregation methods. To address these challenges, firstly, this work introduces a correlation coefficient that is designed to deal with a variety of ranking formats including those containing non-strict (i.e., with-ties) and incomplete (i.e., unknown) preferences. The new measure, which can be regarded as a generalization of the seminal Kendall tau correlation coefficient, is proven to satisfy a set of metric-like axioms and to be equivalent to a recently developed ranking distance function associated with Kemeny aggregation. Secondly, this work derives an exact binary programming formulation for the generalized Kemeny rank aggregation problem---whose ranking inputs may be complete and incomplete, with and without ties. It leverages the equivalence of minimizing the Kemeny-Snell distance and maximizing the Kendall-tau correlation, to compare the newly introduced binary programming formulation to a modified version of an existing integer programming formulation associated with the Kendall-tau distance. Thirdly, this work introduces a new social choice property for decomposing large-size problems into smaller subproblems, which allows solving the problem in a distributed fashion. The new property is adequate for handling complete rankings with ties. The property is leveraged to develop a structural decomposition algorithm, through which certain large instances of the NP-hard Kemeny rank aggregation problem can be solved exactly in a practical amount of time. Lastly, this work applies these rank aggregation mechanisms to novel contexts for extracting collective wisdom in crowdsourcing tasks. Through this crowdsourcing experiment, we assess the capability of aggregation frameworks to recover underlying ground truth and the usefulness of multimodal information in overcoming anchoring effects, which shows its ability to enhance the wisdom of crowds and its practicability to the real-world problem.
ContributorsYoo, Yeawon (Author) / Escobedo, Adolfo R (Thesis advisor) / Mirchandani, Pitu B (Committee member) / Pavlic, Ted P (Committee member) / Chiou, Erin K (Committee member) / Arizona State University (Publisher)
Created2021
161799-Thumbnail Image.png
Description
The control, function, and evolution of sleep in animals has received little attention compared to many other fitness-relevant animal behaviors. Though natural selection has largely been thought of as the driving evolutionary force shaping sleep biology, sexual and social selection may also have transformative effects on sleep quantity and quality

The control, function, and evolution of sleep in animals has received little attention compared to many other fitness-relevant animal behaviors. Though natural selection has largely been thought of as the driving evolutionary force shaping sleep biology, sexual and social selection may also have transformative effects on sleep quantity and quality in animals. An overarching hypothesis is that increased levels of investment into inter-sexual choice and intra-sexual competition will reduce sleep. An alternative hypothesis is that sexual ornamentation (e.g. avian plumage coloration and song) may have evolved to communicate sleep health and may therefore be positively related to sleep investment. In this dissertation, I studied how sleep is related to components of sexual and social selection in animals (mostly in birds). I first reviewed the literature for empirical examples of how social and sexual selection drive animal sleep patterns and found support for this relationship in some common types of inter-individual interactions (e.g. mating, intra-sexual competition, parent-offspring interactions, group interactions); I also provided new ideas and hypotheses for future research. I then tested associations between sleep behavior with expression of ornaments (song and plumage coloration), using the house finch (Haemorhous mexicanus) as a model system. For both color and song, I found support for the hypothesis that individuals with exaggerated ornaments slept deeper and longer, suggesting that sleep is a critical resource for ornament elaboration and/or may be communicated by both types of sexual signal. Following this, I tested the phylogenetic association between sleep and social/sexual selection as well as other life-history traits across birds. I found that more territorial bird species sleep less, that polygynous birds sleep more than monogamous and polygynandrous birds, and that birds migrating longer distances sleep less and have less REM sleep. Finally, in the interest of applying basic knowledge about sleep biology to current global problems, I found support for the hypothesis that house finches from city environments have developed resilience to artificial light pollution at night. Altogether, I found that social, sexual, and life-history traits are indeed important and overlooked drivers of sleep behavior from multiple levels of analysis.
ContributorsHutton, Pierce (Author) / McGraw, Kevin J (Thesis advisor) / Rutowski, Ronald L (Committee member) / Deviche, Pierre J (Committee member) / Sweazea, Karen L (Committee member) / Lesku, John A (Committee member) / Arizona State University (Publisher)
Created2021