Matching Items (43,917)
Description
There is increasing interest in the medical and behavioral health communities towards developing effective strategies for the treatment of chronic diseases. Among these lie adaptive interventions, which consider adjusting treatment dosages over time based on participant response. Control engineering offers a broad-based solution framework for optimizing the effectiveness of such interventions. In this thesis, an approach is proposed to develop dynamical models and subsequently, hybrid model predictive control schemes for assigning optimal dosages of naltrexone, an opioid antagonist, as treatment for a chronic pain condition known as fibromyalgia. System identification techniques are employed to model the dynamics from the daily diary reports completed by participants of a blind naltrexone intervention trial. These self-reports include assessments of outcomes of interest (e.g., general pain symptoms, sleep quality) and additional external variables (disturbances) that affect these outcomes (e.g., stress, anxiety, and mood). Using prediction-error methods, a multi-input model describing the effect of drug, placebo and other disturbances on outcomes of interest is developed. This discrete time model is approximated by a continuous second order model with zero, which was found to be adequate to capture the dynamics of this intervention. Data from 40 participants in two clinical trials were analyzed and participants were classified as responders and non-responders based on the models obtained from system identification. The dynamical models can be used by a model predictive controller for automated dosage selection of naltrexone using feedback/feedforward control actions in the presence of external disturbances. The clinical requirement for categorical (i.e., discrete-valued) drug dosage levels creates a need for hybrid model predictive control (HMPC). The controller features a multiple degree-of-freedom formulation that enables the user to adjust the speed of setpoint tracking, measured disturbance rejection and unmeasured disturbance rejection independently in the closed loop system. The nominal and robust performance of the proposed control scheme is examined via simulation using system identification models from a representative participant in the naltrexone intervention trial. The controller evaluation described in this thesis gives credibility to the promise and applicability of control engineering principles for optimizing adaptive interventions.
Contributors
Deśapāṇḍe, Sunīla (Author) / Rivera, Daniel E. (Thesis advisor) / Si, Jennie (Committee member) / Tsakalis, Konstantinos (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Thousands of children are being injured every day in bicycling accidents. Interventions, like Safe Routes to School, are currently in place to combat injury rates by providing programs to teach children safe biking behaviors. In order to develop effective behavioral change programs, behavior and the components of which it is composed must be understood. Attitudes, subjective norms, and self-efficacy are important predictors of intention to perform a behavior. The purpose of this study was to ascertain the extent to which attitude, subjective norms, self-efficacy, and bike rodeo participation explain third through eighth graders' intentions to bike safely. These constructs were tested using a survey research design in a purposive sample of fifty-seven third through eighth grade students in Safe Routes to School schools in the Southwest. Students took an online survey in the computer lab at their respective schools supervised by a teacher. The study found attitudes to be comprised of three factors: happy/safe, not afraid, and calm. Overall, the model explained approximately 71% of the variance in children's intentions to bike safely, R2=.749, Adjusted R2=.713, F(7, 49)=20.854, p<.01. The significant predictors were happy/safe attitudes, subjective norms, self-efficacy, and a quadratic self-efficacy term explaining 10% (p=.019), 28% (p<.01), 18% (p<.01), and 15% (p<.01) respectively. The results of the study can be used to create future and improve current bike safety interventions for children.
Contributors
Payton, Kayla G (Author) / Rodriguez, Ariel (Thesis advisor) / Tyrrell, Timothy (Committee member) / Maruyama, Kenichi (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Nucleosomes are the basic repetitive unit of eukaryotic chromatin and are responsible for packing DNA inside the nucleus of the cell. They consist of a complex of eight histone proteins (two copies of four proteins H2A, H2B, H3 and H4) around which 147 base pairs of DNA are wrapped in ~1.67 superhelical turns. Although the nucleosomes are stable protein-DNA complexes, they undergo spontaneous conformational changes that occur in an asynchronous fashion. This conformational dynamics, defined by the "site-exposure" model, involves the DNA unwrapping from the protein core and exposing itself transiently before wrapping back. Physiologically, this allows regulatory proteins to bind to their target DNA sites during cellular processes like replication, DNA repair and transcription. Traditional biochemical assays have stablished the equilibrium constants for the accessibility to various sites along the length of the nucleosomal DNA, from its end to the middle of the dyad axis. Using fluorescence correlation spectroscopy (FCS), we have established the position dependent rewrapping rates for nucleosomes. We have also used Monte Carlo simulation methods to analyze the applicability of FRET fluctuation spectroscopy towards conformational dynamics, specifically motivated by nucleosome dynamics. Another important conformational change that is involved in cellular processes is the disassembly of nucleosome into its constituent particles. The exact pathway adopted by nucleosomes is still not clear. We used dual color fluorescence correlation spectroscopy to study the intermediates during nucleosome disassembly induced by changing ionic strength. Studying the nature of nucleosome conformational change and the kinetics is very important in understanding gene expression. The results from this thesis give a quantitative description to the basic unit of the chromatin.
Contributors
Gurunathan, Kaushik (Author) / Levitus, Marcia (Thesis advisor) / Lindsay, Stuart (Committee member) / Woodbury, Neal (Committee member) / Yan, Hao (Committee member) / Arizona State University (Publisher)
Created
2011
Description
This dissertation investigates socio-economic strategies adopted by a small craftworking community situated on the edge of one of the earliest, largest and most complex cities in Mesoamerica. The focus of investigation is San Jose 520, a hamlet located on the southeastern margin of Teotihuacan and occupied primarily during the Tlamimilolpa and Xolalpan phases (ca. A.D. 200-500). Its inhabitants were potters of low socio-economic status living in small, architecturally simple residential structures. The investigation complements much more numerous studies of higher-status groups residing in Teotihuacan's famous apartment compounds, much larger and architecturally more formal structures clustered primarily within built-up parts of the city. The founding residents of San Jose 520 might have initially been immigrants, arriving at Teotihuacan after most of the city was already filled in and occupied, and therefore settling in a spatially marginal area with limited potential for farming. Archaeological field and lab investigations demonstrate that they adopted ceramic production as a strategy of economic survival in a competitive urban system. They specialized in the manufacture of the outcurving bowl--a vessel widely used at Teotihuacan for food service and certain ritual activities. At smaller scales of production, these potters also made other types of serving and ritual vessels and figurines. Evidence relating to mortuary and domestic rituals indicates participation in a number of the rituals typical of other sectors of Teotihuacan society, but not all. The most general goal of this investigation is to improve understanding of how socially and spatially marginal peoples possessing low economic status developed and exploited viable economic niches in pre-industrial urban systems. The San Jose 520 potters appear dynamic in their economic adjustment--in part by enhancing their production system over time through the adoption of various specialized pot-making tools (some as yet undocumented for Teotihuacan), and to some extent by modifying their product line, they survived for many generations. Nevertheless, they never succeeded in significantly raising their economic status; at the time of their apparent disappearance sometime in the Xolalpan phase, these potters and their households continued to constitute a case study of urban poverty in a massive pre-industrial city.
Contributors
Cabrera Cortes, Mercedes Oralia (Author) / Stark, Barbara L. (Thesis advisor) / Cowgill, George L. (Thesis advisor) / Falconer, Steven E. (Committee member) / Spielmann, Katherine A. (Committee member) / Arizona State University (Publisher)
Created
2011
Description
This dissertation is focused on building scalable Attribute Based Security Systems (ABSS), including efficient and privacy-preserving attribute based encryption schemes and applications to group communications and cloud computing. First of all, a Constant Ciphertext Policy Attribute Based Encryption (CCP-ABE) is proposed. Existing Attribute Based Encryption (ABE) schemes usually incur large, linearly increasing ciphertext. The proposed CCP-ABE dramatically reduces the ciphertext to small, constant size. This is the first existing ABE scheme that achieves constant ciphertext size. Also, the proposed CCP-ABE scheme is fully collusion-resistant such that users can not combine their attributes to elevate their decryption capacity. Next step, efficient ABE schemes are applied to construct optimal group communication schemes and broadcast encryption schemes. An attribute based Optimal Group Key (OGK) management scheme that attains communication-storage optimality without collusion vulnerability is presented. Then, a novel broadcast encryption model: Attribute Based Broadcast Encryption (ABBE) is introduced, which exploits the many-to-many nature of attributes to dramatically reduce the storage complexity from linear to logarithm and enable expressive attribute based access policies. The privacy issues are also considered and addressed in ABSS. Firstly, a hidden policy based ABE schemes is proposed to protect receivers' privacy by hiding the access policy. Secondly,a new concept: Gradual Identity Exposure (GIE) is introduced to address the restrictions of hidden policy based ABE schemes. GIE's approach is to reveal the receivers' information gradually by allowing ciphertext recipients to decrypt the message using their possessed attributes one-by-one. If the receiver does not possess one attribute in this procedure, the rest of attributes are still hidden. Compared to hidden-policy based solutions, GIE provides significant performance improvement in terms of reducing both computation and communication overhead. Last but not least, ABSS are incorporated into the mobile cloud computing scenarios. In the proposed secure mobile cloud data management framework, the light weight mobile devices can securely outsource expensive ABE operations and data storage to untrusted cloud service providers. The reported scheme includes two components: (1) a Cloud-Assisted Attribute-Based Encryption/Decryption (CA-ABE) scheme and (2) An Attribute-Based Data Storage (ABDS) scheme that achieves information theoretical optimality.
Contributors
Zhou, Zhibin (Author) / Huang, Dijiang (Thesis advisor) / Yau, Sik-Sang (Committee member) / Ahn, Gail-Joon (Committee member) / Reisslein, Martin (Committee member) / Arizona State University (Publisher)
Created
2011
Description
In the rural, modern American West, two Manichean perspectives of the human-nature relationship have contributed to vehement environmental conflicts. Adopting developer Calvin Black and writer Edward Abbey as archetypes, I explore the endurance of these two ideologies in the redrock canyon country of southern Utah and northern Arizona. Black represents the historically dominant anthropocentric view among Euro Americans that nature ought to be domesticated and commoditized; the competing view, represented by Abbey, is eco-centric and considers the intrinsic value of the broader ecological community beyond its utilitarian function. I argue that environmental conflict in the canyon country has been driven by ideologues who espouse one of these two deeply entrenched and seemingly irreconcilable perspectives. Modern-day conflicts over wilderness, land use, and rural development are endemic, rooted in heritage and culture and driven by particular Anglo-American religious and secular beliefs that reflect differing ways of “seeing” the land. In particular these contending perspectives are reflected in the “built” landscape. Using one especially ubiquitous human imprint on the land as both trope and subject, I explore the political and cultural meanings of roads as symbols variously of progress and of exploitation. Questions of road development and public lands access became the center point of environmental conflict driven by dichotomous worldviews that demonized the opposition and its position. What developed in the last half century is a discourse dictated by categories created by ideologues. This dissertation not only explores the particular circumstances that made these environmental contests volatile in an American desert, but it also meditates broadly on the nature of environmental compromise and conflict, the place of people in "wild" landscapes, and the discontents of rural communities upended by new economic realities. This study illustrates generally how people perceive the land, the technology they wield to manipulate it, and the broader cultural and political transformations that result.
Contributors
Rogers, Jedediah S. (Jedediah Smart), 1978- (Author) / Hirt, Paul W. (Thesis advisor) / Pyne, Stephen J. (Committee member) / Fixico, Donald L. (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Thermoelectric devices (TED's) continue to be an area of high interest in both thermal management and energy harvesting applications. Due to their compact size, reliable performance, and their ability to accomplish sub-ambient cooling, much effort is being focused on optimized methods for characterization and integration of TED's for future applications. Predictive modeling methods can only achieve accurate results with robust input physical parameters, therefore TED characterization methods are critical for future development of the field. Often times, physical properties of TED sub-components are very well known, however the "effective" properties of a TED module can be difficult to measure with certainty. The module-level properties must be included in predictive modeling, since these include electrical and thermal contact resistances which are difficult to analytically derive. A unique characterization method is proposed, which offers the ability to directly measure all device-level physical parameters required for accurate modeling. Among many other unique features, the metrology allows the capability to perform an independent validation of empirical parameters by measuring parasitic heat losses. As support for the accuracy of the measured parameters, the metrology output from an off-the-shelf TED is used in a system-level thermal model to predict and validate observed metrology temperatures. Finally, as an extension to the benefits of this metrology, it is shown that resulting data can be used to empirically validate a device-level dimensionless relationship. The output provides a powerful performance prediction tool, since all physical behavior in a performance domain is captured using a single analytical relationship and can be plotted on a singe graph.
Contributors
Lofgreen, Kelly (Author) / Phelan, Patrick E (Thesis advisor) / Posner, Jonathan (Committee member) / Devasenathipathy, Shankar (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Children removed from methamphetamine laboratories are a severely understudied population despite the widespread deprivation parental methamphetamine abuse has on children, particularly in homes where methamphetamine is produced. Arizona's children are uniquely affected by the use and manufacturing of methamphetamine due to the geographic location and landscape of the state. A sample of 144 children removed from their homes during the seizure of methamphetamine laboratories, as part of the Arizona Drug Endangered Children program between 1999 and 2003, was investigated. Results indicate that younger children were more likely to be reported by Child Protective Services as high or moderate risk of further abuse, test positive for methamphetamine, and have maternal alleged perpetrators of abuse. Older children were more likely to be reported as low risk for further abuse, test negative for methamphetamine, and have paternal alleged perpetrators of abuse. Results also show that children initially placed in foster care were more likely to remain in foster care at the final assessment than to be living with a parent or kin. These findings have implications for individuals working with children removed from methamphetamine laboratories, including Child Protective Services case workers, medical personnel, temporary and permanent child caregivers (i.e., foster care, kin care, adoptive parents, and shelters), and community members (i.e., teachers). Recommendations based on study findings are offered to child and family advocates and interventionists.
Contributors
Pennar, Amy LaRae (Author) / Shapiro, Alyson F. (Thesis advisor) / Bradley, Robert H (Committee member) / Krysik, Judy (Committee member) / Arizona State University (Publisher)
Created
2011
Description
In the former British colony of Malaya, communism is a controversial subject that often invites significant scrutiny from government officials and pro-British scholars who describes the radical movement as a foreign conspiracy to dominate the small Southeast Asian nation. The primary goal of this thesis, therefore, is to reinterpret and revise the current established history of Malayan communism in a chronological and unbiased manner that would illustrate that the authoritative accounts of the movement was not only incomplete but was also written with explicit prejudice. The secondary goal of this thesis is to argue that the members of the Malayan Communist Party were actually nationalists who embraced leftist ideology as a means to fight against colonialism. By examining the programs and manifestoes issued by the Party over the years, it is clear that the communists were in fact had been arguing for social reforms and independence rather than a Russian-style proletarian revolution. This research scrutinizes the authoritative texts written by Cold War-era scholars such as Gene Hanrahan as well as newly published historical analysis of the period by Cheah Boon Kheng in addition to memoirs of surviving members of the Party such as Chin Peng and Abdullah C.D. The evidence indicates that early understandings of the Malayan communist movement were heavily influenced by Cold War paranoia and that over time it had become the accepted version of history.
Contributors
Ng, Sze-Chieh (Author) / Rush, James R (Thesis advisor) / MacKinnon, Stephen R. (Committee member) / Moore, Aaron S (Committee member) / Arizona State University (Publisher)
Created
2011
Description
The Toledo Core Based Statistical Area (CBSA) presents an interesting case study for the new sulfur dioxide (SO2) one hour standard. Since no SO2 monitor within 75 miles to estimate the attainment status of the area, American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) was used in this study to predict potential problems associated with the newly revised standard. The Toledo CBSA is home to two oil refineries, a glass making industry, several coal fired lime kilns, and a sulfuric acid regeneration plant, The CBSA 3 has coal fired power plants within a 30 mile radius of its center. Additionally, Toledo is a major Great Lakes shipping port visited by both lake and ocean going vessels. As a transportation hub, the area is also traversed by several rail lines which feed four rail switching yards. Impacts of older generation freighters, or "steamers", utilizing high sulfur "Bunker C" fuel oil in the area is also an issue. With the unique challenges presented by an SO2 one hour standard, this study attempted to estimate potential problem areas in advance of any monitoring data being gathered. Based on the publicly available data as inputs, it appears that a significant risk of non-attainment may exist in the Toledo CBSA. However, future on-the-books controls and currently proposed regulatory actions appear to drive the risk below significance by 2015. Any designation as non-attainment should be self-correcting and without need for controls other than those used in these models. The outcomes of this screening study are intended for use as a basis for assessments for other mid-sized, industrial areas without SO2 monitors. The results may also be utilized by industries and planning groups within the Toledo CBSA to address potential issues in advance of monitoring system deployment to lower the risk of attaining long term or perpetual non-attainment status.
Contributors
Myers, Greg Francis (Author) / Olson, Larry (Thesis advisor) / Edwards, David (Committee member) / Hristovski, Kiril (Committee member) / Arizona State University (Publisher)
Created
2011