Matching Items (72)
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In this thesis I introduce a new direction to computing using nonlinear chaotic dynamics. The main idea is rich dynamics of a chaotic system enables us to (1) build better computers that have a flexible instruction set, and (2) carry out computation that conventional computers are not good at it.

In this thesis I introduce a new direction to computing using nonlinear chaotic dynamics. The main idea is rich dynamics of a chaotic system enables us to (1) build better computers that have a flexible instruction set, and (2) carry out computation that conventional computers are not good at it. Here I start from the theory, explaining how one can build a computing logic block using a chaotic system, and then I introduce a new theoretical analysis for chaos computing. Specifically, I demonstrate how unstable periodic orbits and a model based on them explains and predicts how and how well a chaotic system can do computation. Furthermore, since unstable periodic orbits and their stability measures in terms of eigenvalues are extractable from experimental times series, I develop a time series technique for modeling and predicting chaos computing from a given time series of a chaotic system. After building a theoretical framework for chaos computing I proceed to architecture of these chaos-computing blocks to build a sophisticated computing system out of them. I describe how one can arrange and organize these chaos-based blocks to build a computer. I propose a brand new computer architecture using chaos computing, which shifts the limits of conventional computers by introducing flexible instruction set. Our new chaos based computer has a flexible instruction set, meaning that the user can load its desired instruction set to the computer to reconfigure the computer to be an implementation for the desired instruction set. Apart from direct application of chaos theory in generic computation, the application of chaos theory to speech processing is explained and a novel application for chaos theory in speech coding and synthesizing is introduced. More specifically it is demonstrated how a chaotic system can model the natural turbulent flow of the air in the human speech production system and how chaotic orbits can be used to excite a vocal tract model. Also as another approach to build computing system based on nonlinear system, the idea of Logical Stochastic Resonance is studied and adapted to an autoregulatory gene network in the bacteriophage λ.
ContributorsKia, Behnam (Author) / Ditto, William (Thesis advisor) / Huang, Liang (Committee member) / Lai, Ying-Cheng (Committee member) / Helms Tillery, Stephen (Committee member) / Arizona State University (Publisher)
Created2011
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Complex dynamical systems consisting interacting dynamical units are ubiquitous in nature and society. Predicting and reconstructing nonlinear dynamics of units and the complex interacting networks among them serves the base for the understanding of a variety of collective dynamical phenomena. I present a general method to address the two outstanding

Complex dynamical systems consisting interacting dynamical units are ubiquitous in nature and society. Predicting and reconstructing nonlinear dynamics of units and the complex interacting networks among them serves the base for the understanding of a variety of collective dynamical phenomena. I present a general method to address the two outstanding problems as a whole based solely on time-series measurements. The method is implemented by incorporating compressive sensing approach that enables an accurate reconstruction of complex dynamical systems in terms of both nodal equations that determines the self-dynamics of units and detailed coupling patterns among units. The representative advantages of the approach are (i) the sparse data requirement which allows for a successful reconstruction from limited measurements, and (ii) general applicability to identical and nonidentical nodal dynamics, and to networks with arbitrary interacting structure, strength and sizes. Another two challenging problem of significant interest in nonlinear dynamics: (i) predicting catastrophes in nonlinear dynamical systems in advance of their occurrences and (ii) predicting the future state for time-varying nonlinear dynamical systems, can be formulated and solved in the framework of compressive sensing using only limited measurements. Once the network structure can be inferred, the dynamics behavior on them can be investigated, for example optimize information spreading dynamics, suppress cascading dynamics and traffic congestion, enhance synchronization, game dynamics, etc. The results can yield insights to control strategies design in the real-world social and natural systems. Since 2004, there has been a tremendous amount of interest in graphene. The most amazing feature of graphene is that there exists linear energy-momentum relationship when energy is low. The quasi-particles inside the system can be treated as chiral, massless Dirac fermions obeying relativistic quantum mechanics. Therefore, the graphene provides one perfect test bed to investigate relativistic quantum phenomena, such as relativistic quantum chaotic scattering and abnormal electron paths induced by klein tunneling. This phenomenon has profound implications to the development of graphene based devices that require stable electronic properties.
ContributorsYang, Rui (Author) / Lai, Ying-Cheng (Thesis advisor) / Duman, Tolga M. (Committee member) / Akis, Richard (Committee member) / Huang, Liang (Committee member) / Arizona State University (Publisher)
Created2012
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Description
What can classical chaos do to quantum systems is a fundamental issue highly relevant to a number of branches in physics. The field of quantum chaos has been active for three decades, where the focus was on non-relativistic quantumsystems described by the Schr¨odinger equation. By developing an efficient method to

What can classical chaos do to quantum systems is a fundamental issue highly relevant to a number of branches in physics. The field of quantum chaos has been active for three decades, where the focus was on non-relativistic quantumsystems described by the Schr¨odinger equation. By developing an efficient method to solve the Dirac equation in the setting where relativistic particles can tunnel between two symmetric cavities through a potential barrier, chaotic cavities are found to suppress the spread in the tunneling rate. Tunneling rate for any given energy assumes a wide range that increases with the energy for integrable classical dynamics. However, for chaotic underlying dynamics, the spread is greatly reduced. A remarkable feature, which is a consequence of Klein tunneling, arise only in relativistc quantum systems that substantial tunneling exists even for particle energy approaching zero. Similar results are found in graphene tunneling devices, implying high relevance of relativistic quantum chaos to the development of such devices. Wave propagation through random media occurs in many physical systems, where interesting phenomena such as branched, fracal-like wave patterns can arise. The generic origin of these wave structures is currently a matter of active debate. It is of fundamental interest to develop a minimal, paradigmaticmodel that can generate robust branched wave structures. In so doing, a general observation in all situations where branched structures emerge is non-Gaussian statistics of wave intensity with an algebraic tail in the probability density function. Thus, a universal algebraic wave-intensity distribution becomes the criterion for the validity of any minimal model of branched wave patterns. Coexistence of competing species in spatially extended ecosystems is key to biodiversity in nature. Understanding the dynamical mechanisms of coexistence is a fundamental problem of continuous interest not only in evolutionary biology but also in nonlinear science. A continuous model is proposed for cyclically competing species and the effect of the interplay between the interaction range and mobility on coexistence is investigated. A transition from coexistence to extinction is uncovered with a non-monotonic behavior in the coexistence probability and switches between spiral and plane-wave patterns arise. Strong mobility can either promote or hamper coexistence, while absent in lattice-based models, can be explained in terms of nonlinear partial differential equations.
ContributorsNi, Xuan (Author) / Lai, Ying-Cheng (Thesis advisor) / Huang, Liang (Committee member) / Yu, Hongbin (Committee member) / Akis, Richard (Committee member) / Arizona State University (Publisher)
Created2012
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Description

This study looked at the accuracy in sexual orientation judgment in college-age students from Arizona State University’s West Campus while viewing female actors. One actor was straight and the other bisexual. Participants viewed a 3-minute-long video with audio and visual of a mock forensic interview between Taylor Addams (played by

This study looked at the accuracy in sexual orientation judgment in college-age students from Arizona State University’s West Campus while viewing female actors. One actor was straight and the other bisexual. Participants viewed a 3-minute-long video with audio and visual of a mock forensic interview between Taylor Addams (played by one of the actors) and Officer Carter (played by Kiersten Carter), and were not told this was a test of their gaydar. It was found that though each group was biased toward straight responses, the straight actor group scored significantly higher on the straightness measure than the bisexual actor group. There was also no significant difference between the two groups in their confidence in their answers.

ContributorsCarter, Kiersten M (Author) / Holloway, Steven (Thesis director) / Walker, Michael (Committee member) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Critical flicker fusion thresholds (CFFTs) describe when quick amplitude modulations of a light source become undetectable as the frequency of the modulation increases and are thought to underlie a number of visual processing skills, including reading. Here, we compare the impact of two vision-training approaches, one involving contrast sensitivity training

Critical flicker fusion thresholds (CFFTs) describe when quick amplitude modulations of a light source become undetectable as the frequency of the modulation increases and are thought to underlie a number of visual processing skills, including reading. Here, we compare the impact of two vision-training approaches, one involving contrast sensitivity training and the other directional dot-motion training, compared to an active control group trained on Sudoku. The three training paradigms were compared on their effectiveness for altering CFFT. Directional dot-motion and contrast sensitivity training resulted in significant improvement in CFFT, while the Sudoku group did not yield significant improvement. This finding indicates that dot-motion and contrast sensitivity training similarly transfer to effect changes in CFFT. The results, combined with prior research linking CFFT to high-order cognitive processes such as reading ability, and studies showing positive impact of both dot-motion and contrast sensitivity training in reading, provide a possible mechanistic link of how these different training approaches impact reading abilities.

ContributorsZhou, Tianyou (Author) / Nanez, Jose (Author) / Zimmerman, Daniel (Author) / Holloway, Steven (Author) / Seitz, Aaron (Author) / New College of Interdisciplinary Arts and Sciences (Contributor)
Created2016-10-26
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Although autism spectrum disorder (ASD) is a serious lifelong condition, its underlying neural mechanism remains unclear. Recently, neuroimaging-based classifiers for ASD and typically developed (TD) individuals were developed to identify the abnormality of functional connections (FCs). Due to over-fitting and interferential effects of varying measurement conditions and demographic distributions, no

Although autism spectrum disorder (ASD) is a serious lifelong condition, its underlying neural mechanism remains unclear. Recently, neuroimaging-based classifiers for ASD and typically developed (TD) individuals were developed to identify the abnormality of functional connections (FCs). Due to over-fitting and interferential effects of varying measurement conditions and demographic distributions, no classifiers have been strictly validated for independent cohorts. Here we overcome these difficulties by developing a novel machine-learning algorithm that identifies a small number of FCs that separates ASD versus TD. The classifier achieves high accuracy for a Japanese discovery cohort and demonstrates a remarkable degree of generalization for two independent validation cohorts in the USA and Japan. The developed ASD classifier does not distinguish individuals with major depressive disorder and attention-deficit hyperactivity disorder from their controls but moderately distinguishes patients with schizophrenia from their controls. The results leave open the viable possibility of exploring neuroimaging-based dimensions quantifying the multiple-disorder spectrum.

ContributorsYahata, Noriaki (Author) / Morimoto, Jun (Author) / Hashimoto, Ryuichiro (Author) / Lisi, Giuseppe (Author) / Shibata, Kazuhisa (Author) / Kawakubo, Yuki (Author) / Kuwabara, Hitoshi (Author) / Kuroda, Miho (Author) / Yamada, Takashi (Author) / Megumi, Fukuda (Author) / Imamizu, Hiroshi (Author) / Nanez, Jose (Author) / Takahashi, Hidehiko (Author) / Okamoto, Yasumasa (Author) / Kasai, Kiyoto (Author) / Kato, Nobumasa (Author) / Sasaki, Yuka (Author) / Watanabe, Takeo (Author) / Kawato, Mitsuo (Author) / New College of Interdisciplinary Arts and Sciences (Contributor)
Created2016-04-14
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Fetal androgen exposure and childhood experiences are believed to contribute to the development and organization of the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes, which are responsible for the regulation and release of stress and sex hormones, respectively. Evidence suggests the HPA and HPG axes can couple in response to childhood

Fetal androgen exposure and childhood experiences are believed to contribute to the development and organization of the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes, which are responsible for the regulation and release of stress and sex hormones, respectively. Evidence suggests the HPA and HPG axes can couple in response to childhood adversity, and that hormonal dysregulation contributes to psychopathological disorders such as anxiety and depression. Recent research also suggests self-compassion interventions could reduce PTSD symptoms, and that the experience of childhood trauma is related to increased empathy. Still, little is known regarding the impact of fetal androgen exposure on PTSD susceptibility and the relationships between self-compassion, compassion for others, and empathy. The current study aims to determine whether fetal androgen exposure mitigates PTSD susceptibility, and to clarify the relationships between empathy, compassion for others, self-compassion, and PTSD symptoms. A sample of 208 adults completed an online survey designed to measure fetal androgen exposure, childhood maltreatment, self-compassion, compassion for others, empathy, and PTSD symptoms. Findings show a significant difference in PTSD symptoms between individuals in high and low fetal androgen exposure groups, and significant correlations were discovered between empathy and compassion for others, empathy and self-compassion, but not compassion for others and self-compassion. Future studies could explore the extent to which fetal androgen exposure influences PTSD symptom susceptibility and the clinical implications therein.

ContributorsMoore, Robin Ann (Author) / Holloway, Steven (Thesis director) / Lewis, Stephen (Committee member) / Nanez, Jose (Committee member) / School of Public Affairs (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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This study evaluated the differences in male and female representation in six different United States law magazines issued from 2005-2017. The initial prediction was that women would appear less often than men in these journals. Four periodicals came from Republican-dominated states, including the Arizona Attorney, Duke Law (NC), S.J.

This study evaluated the differences in male and female representation in six different United States law magazines issued from 2005-2017. The initial prediction was that women would appear less often than men in these journals. Four periodicals came from Republican-dominated states, including the Arizona Attorney, Duke Law (NC), S.J. Quinney’s Res Gestae (UT), and the Notre Dame Lawyer (IN) (no issues published in 2014 through 2016). Two of these magazines were from Democratic regions: Berkeley’s Boalt Hall Transcript (now known as Transcript) (CA) and Richmond Law (VA). Photographic depictions of people within the magazines were recorded, only if text directly referenced the individual(s) as being a lawyer (i.e., attorney, public defender, counselor, associate, and lawyer). The number of male and female depictions in each journal were totaled, and means were compared. The data showed that women were underrepresented in all six of the journals, with effect sizes varying from medium to large. It was also found that although the unequal representation was evident in both red and blue states, the inequity gap was much larger in the red states. Overall, this data supports the notion that depictions of women are underrepresented in law magazines in a profession where they make up half of law school graduates as well as students preparing to enter the legal workforce. However, the gender percentages of those who pass the Bar exam would need to be examined to know more. This lack of parity in gender representations is likely due to society’s stereotypical views of women’s and men’s roles in the context of male-dominated professions, but it also seems to be exacerbated, in part, by a state’s political affiliation. This potential equality issue may have gone unnoticed if it weren’t for research that looks into gender differences, such as this study, which should be taken further by others to gather more data on possible discrimination and produce necessary solutions.
ContributorsReissen, Emily Brook (Author) / Holloway, Steven (Thesis director) / Van Etten, Kathryn (Committee member) / School of Social and Behavioral Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
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Lutein and zeaxanthin are two important carotenoid vitamins related to ocular health and human visual processing. These vitamins can be ingested through supplementation and in regular diet. They concentrate in the central retina where they form a filter of macular pigment and protect the eye from high energy blue and

Lutein and zeaxanthin are two important carotenoid vitamins related to ocular health and human visual processing. These vitamins can be ingested through supplementation and in regular diet. They concentrate in the central retina where they form a filter of macular pigment and protect the eye from high energy blue and yellow light. We examined participants who had a natural diet of high vs low lutein and zeaxanthin intake on tests of contrast sensitivity and glare disability. We also examined participant performance while wearing blue light blocking glasses in order to determine whether these glasses serve a similar protective function as macular pigment in benefiting participants on contrast sensitivity and glare disability tasks. Most of our data did not show statistically significant differences between the high and low lutein and zeaxanthin groups. An unexpected result that the blue blocker glasses hindered the ability of low lutein participants on their glare disability test was observed. We hypothesize that this is due to light scatter produced by the by glasses resulting in an impoverish retinal image reaching the primary visual cortex. Further research is required to examine this new finding.
ContributorsHormann, Breanna Susanne (Author) / Holloway, Steven (Thesis director) / Náñez Sr., José E (Committee member) / School of Mathematical and Natural Sciences (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
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Androgen has been shown to affect functioning of the central nervous system by modulating neural circuitry during in-utero development subsequently affecting parts of the brain implicated in the evaluation of socially relevant stimuli. This can suggest an examination of underlying neurobiological mechanisms that may influence androgen in the brain and

Androgen has been shown to affect functioning of the central nervous system by modulating neural circuitry during in-utero development subsequently affecting parts of the brain implicated in the evaluation of socially relevant stimuli. This can suggest an examination of underlying neurobiological mechanisms that may influence androgen in the brain and likewise human cognition and behavior. Since the index and ring finger ratio is associated with androgen related outcomes, this study sought to identify a relationship between a participant's implicit race association test score and left-handed ring (4D) and index (2D) finger ratio. Specifically, we found that higher androgen exposure in our female subjects equated to a stronger bias for European American faces over African American faces.
ContributorsSaari, Sydney (Author) / Holloway, Steven (Thesis director) / Kim, Linda (Committee member) / Nanez, Jose (Committee member) / Barrett, The Honors College (Contributor)
Created2018-05