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This dissertation examines contemporary U.S. women writing about war, with primarily women subjects and protagonists, from 1991-2013, in fiction, memoir, and media. The writers situate women at the center of war texts and privilege their voices as authoritative speakers in war, whether as civilians and soldiers trying to survive or indigenous women preparing for the possibility of war. I argue that these authors are rewriting scripts of war to reflect gendered experiences and opening new ways of thinking about war. Women Rewriting Scripts of War argues that Leslie Marmon Silko’s novel Almanac of the Dead juxtaposes an indigenous Story concept against a white industrialized national “Truth,” and indigenous women characters will resort to war if needed to oppose it. Silko’s and the other texts here challenge readers to unseat assumptions about the sovereignty of the U.S. and other countries, about the fixedness of gender, of capitalism, and of how humans relate to each other‒and how we should. I argue in Essay 3 that the script of “the body” or “the soldier” in military service can be expanded by moving toward language and concepts from feminist and queer theory and spectrums of gender and sexuality. This can contribute to positive change for all military members. In each of the texts, there are some similarities in connections with others. Connections enable solidarity for change, possibilities for healing, and survival; indeed, without connections with others to work together, survival is not possible. Changes to established economic structures become necessary for women in Barbara Kingsolver’s novel The Poisonwood Bible; I argue that women engaging in alternative modes of economy subvert the dominant economic constraints, gender hierarchies, and social isolation during and after war in the Congo. In Essay 5, I explore two fictional texts about the U.S. wars in Iraq and Afghanistan, Helen Benedict's novel Sand Queen and Katey Schultz’s short story collection Flashes of War. The connections in these women’s texts about war are not idealized, and they function as the antithesis to the fragmentation and isolation of postmodern texts.
This dissertation examines contemporary U.S. women writing about war, with primarily women subjects and protagonists, from 1991-2013, in fiction, memoir, and media. The writers situate women at the center of war texts and privilege their voices as authoritative speakers in war, whether as civilians and soldiers trying to survive or indigenous women preparing for the possibility of war. I argue that these authors are rewriting scripts of war to reflect gendered experiences and opening new ways of thinking about war. Women Rewriting Scripts of War argues that Leslie Marmon Silko’s novel Almanac of the Dead juxtaposes an indigenous Story concept against a white industrialized national “Truth,” and indigenous women characters will resort to war if needed to oppose it. Silko’s and the other texts here challenge readers to unseat assumptions about the sovereignty of the U.S. and other countries, about the fixedness of gender, of capitalism, and of how humans relate to each other‒and how we should. I argue in Essay 3 that the script of “the body” or “the soldier” in military service can be expanded by moving toward language and concepts from feminist and queer theory and spectrums of gender and sexuality. This can contribute to positive change for all military members. In each of the texts, there are some similarities in connections with others. Connections enable solidarity for change, possibilities for healing, and survival; indeed, without connections with others to work together, survival is not possible. Changes to established economic structures become necessary for women in Barbara Kingsolver’s novel The Poisonwood Bible; I argue that women engaging in alternative modes of economy subvert the dominant economic constraints, gender hierarchies, and social isolation during and after war in the Congo. In Essay 5, I explore two fictional texts about the U.S. wars in Iraq and Afghanistan, Helen Benedict's novel Sand Queen and Katey Schultz’s short story collection Flashes of War. The connections in these women’s texts about war are not idealized, and they function as the antithesis to the fragmentation and isolation of postmodern texts.
ContributorsStamper, Cambria A (Author) / Clarke, Deborah (Thesis advisor) / Hogue, Cynthia (Committee member) / Fonow, Mary Margaret (Committee member) / Arizona State University (Publisher)
Created2015
Description
Background: Heart failure is the leading cause of hospitalization in older adults and has the highest 30-day readmission rate of all diagnoses. An estimated 30 to 60 percent of older adults lose some degree of physical function in the course of an acute hospital stay. Few studies have addressed the role of posture and mobility in contributing to, or improving, physical function in older hospitalized adults. No study to date that we are aware of has addressed this in the older heart failure population.
Purpose: To investigate the predictive value of mobility during a hospital stay and patterns of mobility during the month following discharge on hospital readmission and 30-day changes in functional status in older heart failure patients.
Methods: This was a prospective observational study of 21 older (ages 60+) patients admitted with a primary diagnosis of heart failure. Patients wore two inclinometric accelerometers (rib area and thigh) to record posture and an accelerometer placed at the ankle to record ambulatory activity. Patients wore all sensors continuously during hospitalization and the ankle accelerometer for 30 days after hospital discharge. Function was assessed in all patients the day after hospital discharge and again at 30 days post-discharge.
Results: Five patients (23.8%) were readmitted within the 30 day post-discharge period. None of the hospital or post-discharge mobility measures were associated with readmission after adjustment for covariates. Higher percent lying time in the hospital was associated with slower Timed Up and Go (TUG) time (b = .08, p = .01) and poorer hand grip strength (b = -13.94, p = .02) at 30 days post-discharge. Higher daily stepping activity during the 30 day post-discharge period was marginally associated with improvements in SPPB scores at 30 days (b = <.001, p = .06).
Conclusion: For older heart failure patients, increased time lying while hospitalized is associated with slower walking time and poor hand grip strength 30 days after discharge. Higher daily stepping after discharge may be associated with improvements in physical function at 30 days.
Purpose: To investigate the predictive value of mobility during a hospital stay and patterns of mobility during the month following discharge on hospital readmission and 30-day changes in functional status in older heart failure patients.
Methods: This was a prospective observational study of 21 older (ages 60+) patients admitted with a primary diagnosis of heart failure. Patients wore two inclinometric accelerometers (rib area and thigh) to record posture and an accelerometer placed at the ankle to record ambulatory activity. Patients wore all sensors continuously during hospitalization and the ankle accelerometer for 30 days after hospital discharge. Function was assessed in all patients the day after hospital discharge and again at 30 days post-discharge.
Results: Five patients (23.8%) were readmitted within the 30 day post-discharge period. None of the hospital or post-discharge mobility measures were associated with readmission after adjustment for covariates. Higher percent lying time in the hospital was associated with slower Timed Up and Go (TUG) time (b = .08, p = .01) and poorer hand grip strength (b = -13.94, p = .02) at 30 days post-discharge. Higher daily stepping activity during the 30 day post-discharge period was marginally associated with improvements in SPPB scores at 30 days (b = <.001, p = .06).
Conclusion: For older heart failure patients, increased time lying while hospitalized is associated with slower walking time and poor hand grip strength 30 days after discharge. Higher daily stepping after discharge may be associated with improvements in physical function at 30 days.
ContributorsFloegel, Theresa A (Author) / Buman, Matthew P (Thesis advisor) / Hooker, Steven (Committee member) / Dickinson, Jared (Committee member) / DerAnanian, Cheryl (Committee member) / McCarthy, Marianne (Committee member) / Arizona State University (Publisher)
Created2015
Description
This dissertation examines a planned missing data design in the context of mediational analysis. The study considered a scenario in which the high cost of an expensive mediator limited sample size, but in which less expensive mediators could be gathered on a larger sample size. Simulated multivariate normal data were generated from a latent variable mediation model with three observed indicator variables, M1, M2, and M3. Planned missingness was implemented on M1 under the missing completely at random mechanism. Five analysis methods were employed: latent variable mediation model with all three mediators as indicators of a latent construct (Method 1), auxiliary variable model with M1 as the mediator and M2 and M3 as auxiliary variables (Method 2), auxiliary variable model with M1 as the mediator and M2 as a single auxiliary variable (Method 3), maximum likelihood estimation including all available data but incorporating only mediator M1 (Method 4), and listwise deletion (Method 5).
The main outcome of interest was empirical power to detect the mediated effect. The main effects of mediation effect size, sample size, and missing data rate performed as expected with power increasing for increasing mediation effect sizes, increasing sample sizes, and decreasing missing data rates. Consistent with expectations, power was the greatest for analysis methods that included all three mediators, and power decreased with analysis methods that included less information. Across all design cells relative to the complete data condition, Method 1 with 20% missingness on M1 produced only 2.06% loss in power for the mediated effect; with 50% missingness, 6.02% loss; and 80% missingess, only 11.86% loss. Method 2 exhibited 20.72% power loss at 80% missingness, even though the total amount of data utilized was the same as Method 1. Methods 3 – 5 exhibited greater power loss. Compared to an average power loss of 11.55% across all levels of missingness for Method 1, average power losses for Methods 3, 4, and 5 were 23.87%, 29.35%, and 32.40%, respectively. In conclusion, planned missingness in a multiple mediator design may permit higher quality characterization of the mediator construct at feasible cost.
The main outcome of interest was empirical power to detect the mediated effect. The main effects of mediation effect size, sample size, and missing data rate performed as expected with power increasing for increasing mediation effect sizes, increasing sample sizes, and decreasing missing data rates. Consistent with expectations, power was the greatest for analysis methods that included all three mediators, and power decreased with analysis methods that included less information. Across all design cells relative to the complete data condition, Method 1 with 20% missingness on M1 produced only 2.06% loss in power for the mediated effect; with 50% missingness, 6.02% loss; and 80% missingess, only 11.86% loss. Method 2 exhibited 20.72% power loss at 80% missingness, even though the total amount of data utilized was the same as Method 1. Methods 3 – 5 exhibited greater power loss. Compared to an average power loss of 11.55% across all levels of missingness for Method 1, average power losses for Methods 3, 4, and 5 were 23.87%, 29.35%, and 32.40%, respectively. In conclusion, planned missingness in a multiple mediator design may permit higher quality characterization of the mediator construct at feasible cost.
ContributorsBaraldi, Amanda N (Author) / Enders, Craig K. (Thesis advisor) / Mackinnon, David P (Thesis advisor) / Aiken, Leona S. (Committee member) / Tein, Jenn-Yun (Committee member) / Arizona State University (Publisher)
Created2015
Description
There is a strong medical need and important therapeutic applications for improved wireless bioelectric interfaces to the nervous system. Multichannel devices are desired for neural control of robotic prosthetics that interface to remaining nerves in limb stumps of amputees and as alternatives to traditional wired arrays used in for some types of brain stimulation. This present work investigates a new approach to ultrasound-powering of implantable microelectronic devices within the tissue that may better support such applications. These devices are of ultra-miniature size that is enabled by a wireless technique. This study investigates two types of ultrasound-powered neural interfaces for multichannel sensory feedback in neurostimulation. The piezoceramics lead zirconate titanate (PZT) ceramic and polyvinylidene fluoride (PVDF) polymer were the primary materials used to build the devices. They convert ultrasound to electricity that when rectified by a diode produce a current output that is neuro stimulatory to peripheral nerve or the neurons in the brain. Multichannel devices employ a form of spatial multiplexing that directs focused ultrasound towards localized and segmented regions of PVDF or PZT that allows independent channels of nerve actuation. Different frequencies of ultrasound were evaluated for best results. Firstly, a 2.25 MHz frequency signal that is reasonably penetrating through body tissue to an implant several centimeters deep and also a 5 MHz frequency more suited to application for actuation of devices within a less than a centimeter of nerve. Results show multichannel device performance to have a complex inter-relationship with frequency, size and thickness, angular incidence, channel separations, and number of folds (layers connected in series and parallel). The output electrical port impedances of PVDF devices were examined in relationship to that of stimulating electrodes and tissue interfaces. Miniature multichannel devices were constructed using an unreported method of employing state of the art laser cutting systems. The results show that PVDF based devices have advantages over PZT, because of better acoustic coupling with tissue, known better biocompatibility, and better separation between multiple channels. However, the PZT devices proved to be better overall in terms of compactness and higher outputs for a given ultrasound power level.
ContributorsNanda Kumar, Yashwanth (Author) / Towe, Bruce (Thesis advisor) / Muthuswamy, Jitendran (Committee member) / Nikkhah, Mehdi (Committee member) / Arizona State University (Publisher)
Created2015
Description
Excessive gestational weight gain (GWG) during pregnancy is a major public health concern. Studies have reported more than 70% of pregnant women gain excessive weight which may pose increased maternal and fetal risks. Little is known about the relationships of GWG to behavioral factors (i.e., physical activity, sleep, social support) and maternal mental health (i.e., stress, anxiety, depression) during pregnancy. This descriptive, cross-sectional study explored the relationships of GWG to behavioral factors and maternal mental health during pregnancy. Secondarily, this study described the preferences, uses of, and interests in alternative approaches as well as the mental health differences between users and non-users of alternative approaches during pregnancy. A national survey was administered to women ≥8 weeks pregnant, ≥18 years old, and residing in the United States (N=968). Bivariate correlations were used to determine relationships between GWG and variables of interest. Independent t-tests were used to observe mental health differences between users and non-users of alternative approaches. Data were analyzed throughout pregnancy and by trimester. Throughout pregnancy, significant relationships were found in GWG to stressful events (r=-.112, p<.01), depression (r=.066, p<.05), mindfulness (r=-.067, p<.05), and sleep (r=.089, p<.01). When GWG was assessed by trimester, stressful events were significant in the second (r=-.216, p<.01) and third trimesters (r=-.085, p<.05). Depression remained positively related to GWG in the first (r=.409, p<.01) and second trimesters (r=.162, p<.01). A positive relationship emerged between GWG and anxiety in the first trimester (r=.340, p<.01) and physical activity became significant in the second (r=-.136; p<.05) and third trimesters (r=-.100; p<.05). Mindfulness was the only variable significantly related to GWG throughout all time points. Mean anxiety (d=.236; p=.001) and depression (d=.265; p<.001) scores were significantly lower in users compared to non-users of alternative approaches throughout pregnancy and when assessed by trimester anxiety (d=.424; p=.001) and depression (d=.526; p<.001) were significant in the second trimester. This study provides a framework for future analyses in GWG and maternal mental health. The information presented here may inform future interventions to test the effectiveness of alternative approaches to simultaneously manage maternal mental health and GWG due to the integrative nature of alternative approaches.
ContributorsMatthews, Jennifer L. (Author) / Huberty, Jennifer L (Thesis advisor) / Leiferman, Jenn (Committee member) / Larkey, Linda (Committee member) / McClain, Darya (Committee member) / Arizona State University (Publisher)
Created2015
Description
Vitamin D deficiency has been previously associated with a higher Alzheimer’s disease (AD) risk, a condition marked by dependent living and severe cognitive impairment. AD is histologically defined by the presence of brain amyloid beta (Aβ) plaques and neurofibrillary tangles. Ways to enhance Aβ clearance have been examined in order to sustain cognition and delay AD onset. In vitro and in vivo studies suggest that vitamin D might enhance brain Aβ transportation to the periphery by up-regulating P-glycoprotein production. The purpose of this study was to examine the effect of vitamin D supplementation on plasma Aβ in an older population.
This study was a parallel-arm, double-blinded, randomized control trial. Participants consumed either a vitamin D supplement or placebo once a week for eight weeks (n=23). Only vitamin D insufficient (serum total 25-OH, D < 30 ng/mL) people were included in the study, and all participants were considered to be cognitively normal (MMSE scores > 27). Serum total 25-OH, D and plasma Aβ1-40 measurements were recorded before and after the eight-week trial. The plasma Aβ1-40 change was compared between the vitamin D group and control group.
The vitamin D group experienced a 45% greater change in plasma Aβ1-40 than the control group. The effect size was 0.228 when controlling for baseline plasma Aβ1-40 (p=0.045), 0.197 when controlling for baseline plasma Aβ1-40 and baseline physical activity (p=0.085), and 0.179 when controlling for baseline plasma Aβ1-40, baseline physical activity, and age (p=0.116). In conclusion, vitamin D supplementation might increase brain Aβ clearance in humans, but physical activity and age also appear to modulate Aβ metabolism.
This study was a parallel-arm, double-blinded, randomized control trial. Participants consumed either a vitamin D supplement or placebo once a week for eight weeks (n=23). Only vitamin D insufficient (serum total 25-OH, D < 30 ng/mL) people were included in the study, and all participants were considered to be cognitively normal (MMSE scores > 27). Serum total 25-OH, D and plasma Aβ1-40 measurements were recorded before and after the eight-week trial. The plasma Aβ1-40 change was compared between the vitamin D group and control group.
The vitamin D group experienced a 45% greater change in plasma Aβ1-40 than the control group. The effect size was 0.228 when controlling for baseline plasma Aβ1-40 (p=0.045), 0.197 when controlling for baseline plasma Aβ1-40 and baseline physical activity (p=0.085), and 0.179 when controlling for baseline plasma Aβ1-40, baseline physical activity, and age (p=0.116). In conclusion, vitamin D supplementation might increase brain Aβ clearance in humans, but physical activity and age also appear to modulate Aβ metabolism.
ContributorsMiller, Brendan Joseph (Author) / Johnston, Carol (Thesis advisor) / Whisner, Corrie (Committee member) / Tasevska, Natasha (Committee member) / Arizona State University (Publisher)
Created2015
Description
Biological soil crusts (BSCs) dominate the soil surface of drylands in the western United States and possess properties thought to influence local hydrology. Little agreement exists, however, on the effects of BSCs on runoff, infiltration, and evaporative rates. This study aims to improve the predictive capability of an ecohydrology model in order to understand how BSCs affect the storage, retention, and infiltration of water into soils characteristic of the Colorado Plateau. A set of soil moisture measurements obtained at a climate manipulation experiment near Moab, Utah, are used for model development and testing. Over five years, different rainfall treatments over experimental plots resulted in the development of BSC cover with different properties that influence soil moisture differently. This study used numerical simulations to isolate the relative roles of different BSC properties on the hydrologic response at the plot-scale. On-site meteorological, soil texture and vegetation property datasets are utilized as inputs into a ecohydrology model, modified to include local processes: (1) temperature-dependent precipitation partitioning, snow accumulation and melt, (2) seasonally-variable potential evapotranspiration, (3) plant species-specific transpiration factors, and (4) a new module to account for the water balance of the BSC. Soil, BSC and vegetation parameters were determined from field measurements or through model calibration to the soil moisture observations using the Shuffled Complex Evolution algorithm. Model performance is assessed against five years of soil moisture measurements at each experimental site, representing a wide range of crust cover properties. Simulation experiments were then carried out using the calibrated ecohydrology model in which BSC parameters were varied according to the level of development of the BSC, as represented by the BSC roughness. These results indicate that BSCs act to both buffer against evaporative soil moisture losses by enhancing BSC moisture evaporation and significantly alter the rates of soil water infiltration by reducing moisture storage and increasing conductivity in the BSC. The simulation results for soil water infiltration, storage and retention across a wide range of meteorological events help explain the conflicting hydrologic outcomes present in the literature on BSCs. In addition, identifying how BSCs mediate infiltration and evaporation processes has implications for dryland ecosystem function in the western United States.
ContributorsWhitney, Kristen M (Author) / Vivoni, Enrique R (Thesis advisor) / Farmer, Jack D (Committee member) / Garcia-Pichel, Ferran (Committee member) / Arizona State University (Publisher)
Created2015
Description
In 1975 the Canadian Broadcasting Company (CBC) invited John Cage to write a composition for the bicentennial birthday of the United States. The result was Lecture on the Weather, a multi-media work for twelve expatriate vocalists and/or players with independent sound systems, magnetic tape, and film. Cage used texts by Henry David Thoreau, recordings of environmental sounds made by American composer Maryanne Amacher and a nature-inspired film by Chilean visual artist Luis Frangella. The composition opens with a spoken Preface and is arguably one of Cage’s most overtly political pieces. A year later the National Endowment of the Arts (NEA) and six major United States orchestras commissioned Cage to compose another work commemorating the United States bicentennial of the American Revolution. In response, he created Renga with Apartment House 1776, which follows his concept of a “music circus,” or simply, a musical composition with a multiplicity of events occurring simultaneously. Scored for voices, instrumental soloists and quartets, Renga with Apartment House is a multi-faceted work marked by layers of American hymns and folk tunes.
Cage’s United States Bicentennial compositions – and his other pieces created in the 1970s and 1980s – have received little attention from music scholars. Unique and provocative works within his oeuvre, these compositions raise many questions. Why was Cage commissioned to write these works? How did Cage pay tribute to this celebratory event in American history? What socio–political meanings are implied in these pieces? In this thesis I will provide political, cultural, and biographical contexts of these works. I will further examine their genesis, analyze their scores and selected performances, reflect on their meaning and critical implications and consider the reception of these works. My research draws on unpublished documents housed in the CBC’s archives at McGill University, the archives of C. F. Peters, the New York Public Library and it builds on research of such scholars as David W. Bernstein, William Brooks, Benjamin Piekut, and Christopher Shultis. This thesis offers new information and perspectives on Cage’s creative work in the 1970s and aims at filling a significant gap in Cage scholarship.
Cage’s United States Bicentennial compositions – and his other pieces created in the 1970s and 1980s – have received little attention from music scholars. Unique and provocative works within his oeuvre, these compositions raise many questions. Why was Cage commissioned to write these works? How did Cage pay tribute to this celebratory event in American history? What socio–political meanings are implied in these pieces? In this thesis I will provide political, cultural, and biographical contexts of these works. I will further examine their genesis, analyze their scores and selected performances, reflect on their meaning and critical implications and consider the reception of these works. My research draws on unpublished documents housed in the CBC’s archives at McGill University, the archives of C. F. Peters, the New York Public Library and it builds on research of such scholars as David W. Bernstein, William Brooks, Benjamin Piekut, and Christopher Shultis. This thesis offers new information and perspectives on Cage’s creative work in the 1970s and aims at filling a significant gap in Cage scholarship.
ContributorsFinkel, Joseph Christopher (Author) / Feisst, Sabine M (Thesis advisor) / Rogers, Rodney (Committee member) / Solís, Ted (Committee member) / Arizona State University (Publisher)
Created2015
Description
The holy grail of computer hardware across all market segments has been to sustain performance improvement at the same pace as silicon technology scales. As the technology scales and the size of transistors shrinks, the power consumption and energy usage per transistor decrease. On the other hand, the transistor density increases significantly by technology scaling. Due to technology factors, the reduction in power consumption per transistor is not sufficient to offset the increase in power consumption per unit area. Therefore, to improve performance, increasing energy-efficiency must be addressed at all design levels from circuit level to application and algorithm levels.
At architectural level, one promising approach is to populate the system with hardware accelerators each optimized for a specific task. One drawback of hardware accelerators is that they are not programmable. Therefore, their utilization can be low as they perform one specific function. Using software programmable accelerators is an alternative approach to achieve high energy-efficiency and programmability. Due to intrinsic characteristics of software accelerators, they can exploit both instruction level parallelism and data level parallelism.
Coarse-Grained Reconfigurable Architecture (CGRA) is a software programmable accelerator consists of a number of word-level functional units. Motivated by promising characteristics of software programmable accelerators, the potentials of CGRAs in future computing platforms is studied and an end-to-end CGRA research framework is developed. This framework consists of three different aspects: CGRA architectural design, integration in a computing system, and CGRA compiler. First, the design and implementation of a CGRA and its instruction set is presented. This design is then modeled in a cycle accurate system simulator. The simulation platform enables us to investigate several problems associated with a CGRA when it is deployed as an accelerator in a computing system. Next, the problem of mapping a compute intensive region of a program to CGRAs is formulated. From this formulation, several efficient algorithms are developed which effectively utilize CGRA scarce resources very well to minimize the running time of input applications. Finally, these mapping algorithms are integrated in a compiler framework to construct a compiler for CGRA
At architectural level, one promising approach is to populate the system with hardware accelerators each optimized for a specific task. One drawback of hardware accelerators is that they are not programmable. Therefore, their utilization can be low as they perform one specific function. Using software programmable accelerators is an alternative approach to achieve high energy-efficiency and programmability. Due to intrinsic characteristics of software accelerators, they can exploit both instruction level parallelism and data level parallelism.
Coarse-Grained Reconfigurable Architecture (CGRA) is a software programmable accelerator consists of a number of word-level functional units. Motivated by promising characteristics of software programmable accelerators, the potentials of CGRAs in future computing platforms is studied and an end-to-end CGRA research framework is developed. This framework consists of three different aspects: CGRA architectural design, integration in a computing system, and CGRA compiler. First, the design and implementation of a CGRA and its instruction set is presented. This design is then modeled in a cycle accurate system simulator. The simulation platform enables us to investigate several problems associated with a CGRA when it is deployed as an accelerator in a computing system. Next, the problem of mapping a compute intensive region of a program to CGRAs is formulated. From this formulation, several efficient algorithms are developed which effectively utilize CGRA scarce resources very well to minimize the running time of input applications. Finally, these mapping algorithms are integrated in a compiler framework to construct a compiler for CGRA
ContributorsHamzeh, Mahdi (Author) / Vrudhula, Sarma (Thesis advisor) / Gopalakrishnan, Kailash (Committee member) / Shrivastava, Aviral (Committee member) / Wu, Carole-Jean (Committee member) / Arizona State University (Publisher)
Created2015
Description
Emerging trends in cyber system security breaches in critical cloud infrastructures show that attackers have abundant resources (human and computing power), expertise and support of large organizations and possible foreign governments. In order to greatly improve the protection of critical cloud infrastructures, incorporation of human behavior is needed to predict potential security breaches in critical cloud infrastructures. To achieve such prediction, it is envisioned to develop a probabilistic modeling approach with the capability of accurately capturing system-wide causal relationship among the observed operational behaviors in the critical cloud infrastructure and accurately capturing probabilistic human (users’) behaviors on subsystems as the subsystems are directly interacting with humans. In our conceptual approach, the system-wide causal relationship can be captured by the Bayesian network, and the probabilistic human behavior in the subsystems can be captured by the Markov Decision Processes. The interactions between the dynamically changing state graphs of Markov Decision Processes and the dynamic causal relationships in Bayesian network are key components in such probabilistic modelling applications. In this thesis, two techniques are presented for supporting the above vision to prediction of potential security breaches in critical cloud infrastructures. The first technique is for evaluation of the conformance of the Bayesian network with the multiple MDPs. The second technique is to evaluate the dynamically changing Bayesian network structure for conformance with the rules of the Bayesian network using a graph checker algorithm. A case study and its simulation are presented to show how the two techniques support the specific parts in our conceptual approach to predicting system-wide security breaches in critical cloud infrastructures.
ContributorsNagaraja, Vinjith (Author) / Yau, Stephen S. (Thesis advisor) / Ahn, Gail-Joon (Committee member) / Davulcu, Hasan (Committee member) / Arizona State University (Publisher)
Created2015