abstract: Woven fabric composite materials are widely used in the construction of aircraft engine fan containment systems, mostly due to their high strength to weight ratios and ease of implementation. The development of a predictive model for fan blade containment would provide great benefit to engine manufactures in shortened development cycle time, less risk in certification and fewer dollars lost to redesign/recertification cycles. A mechanistic user-defined material model subroutine has been developed at Arizona State University (ASU) that captures the behavioral response of these fabrics, namely Kevlar® 49, under ballistic loading. Previously developed finite element models used to validate the consistency of this material model neglected the effects of the physical constraints imposed on the test setup during ballistic testing performed at NASA Glenn Research Center (NASA GRC). Part of this research was to explore the effects of these boundary conditions on the results of the numerical simulations. These effects were found to be negligible in most instances. Other material models for woven fabrics are available in the LS-DYNA finite element code. One of these models, MAT234: MAT_VISCOELASTIC_LOOSE_FABRIC (Ivanov & Tabiei, 2004) was studied and implemented in the finite element simulations of ballistic testing associated with the FAA ASU research. The results from these models are compared to results obtained from the ASU UMAT as part of this research. The results indicate an underestimation in the energy absorption characteristics of the Kevlar 49 fabric containment systems. More investigation needs to be performed in the implementation of MAT234 for Kevlar 49 fabric. Static penetrator testing of Kevlar® 49 fabric was performed at ASU in conjunction with this research. These experiments are designed to mimic the type of loading experienced during fan blade out events. The resulting experimental strains were measured using a non-contact optical strain measurement system (ARAMIS). / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2012

This thesis offers a feminist analysis of the gendered public discourses surrounding notions of talent, authenticity and containment. Using two of the most polarizing stars in North America – ‘Snooki’ and Kim Kardashian – the author offers an analysis of how both hard and soft news frame our everyday understanding of women’s public work. Textual analyses of news articles demonstrated that displays of sexual power were most undermined by the media while attempts to venture beyond the reality television texts were contained. On the other hand, the news media were more likely to use positive framing when women were seen to be fulfilling more traditional roles such as wife and mother. The empirical research approach provides an original framework which can be applied to other female public figures to examine how such ideological and gendered discourses shape our understanding of women’s work as well as, more generally, women’s roles in our society.

The following dissertation is an attempt of analysis and understanding of the foreign policy of the United States in the Middle East region and its evolution through time. Considering the fact that the Middle East region is or at least used to be a vital region for the United States national interests, the dissertation presents an exhaustive list of major events that have been major shifts in the US foreign policy in the region. The more or less chronological timeline allows the reader to have a better understanding of the evolution of the US foreign policy. The result of the dissertation is the identification of different patterns of foreign policy and to put the spot on the reasons of the changes of these patterns. Nevertheless, the history of the Middle East region and the incredible number of major events through the 2Oth century and the early 21st century make impossible to deal with all of them. Moreover, analysis and comments are based on academic research, but the dissertation remains subjective and may lead to discussions and debates.

Many real word networks exhibit cascading phenomena, e.g., disease outbreaks in social contact networks, malware propagation in computer networks, failures in cyber-physical systems such as power grids. As they grow in size and complexity, their security becomes increasingly important. In this thesis, we address the problems of controlling cascading failures in various network settings. We address the cascading phenomena which are either natural (e.g., disease outbreaks) or malicious (e.g., cyber attacks). We consider the nodes of a network as being individually or collectively controlled by self-interested autonomous agents and study their strategic decisions in the presence of these failure cascades. There are many models of cascading failures which specify how a node would fail when some neighbors have failed, such as: (i) epidemic spread models in which the cascading can be viewed as a natural and stochastic process and (ii) cyber attack models where the cascade is driven by malicious intents. We present our analyses and algorithms for these models in two parts. Part I focuses on problems of controlling epidemic spread. Epidemic outbreaks are generally modeled as stochastic diffusion processes. In particular, we consider the SIS model on networks. There exist heuristic centralized approaches in the literature for containing epidemic spread in SIS/SIR models; however no rigorous performance bounds are known for these approaches. We develop algorithms with provable approximation guarantees that involve either protective intervention (e.g., vaccination) or link removal (e.g., unfriending). Our approach relies on the characterization of the SIS model in terms of the spectral radius of the network. The centralized approaches, however, are sometimes not feasible in practice. For example, targeted vaccination is often not feasible because of limited compliance to directives. This issue has been addressed in the literature by formulating game theoretic models for the containment of epidemic spread. However they generally assume simplistic propagation models or homogeneous network structures. We develop novel game formulations which rely on the spectral characterization of the SIS model. In these formulations, the failures start from a random set of nodes and propagate through the network links. Each node acts as a self-interested agent and makes strategic intervention decisions (e.g., taking vaccination). Each agent decides its strategy to optimize its payoff (modeled by some payoff function). We analyze the complexity of finding Nash equilibria (NE) and study the structure of NE for different networks in these game settings. Part II focuses on malware spread in networks. In cybersecurity literature malware spreads are often studied in the framework of ``attack graph" models. In these models, a node represents either a physical computing unit or a network configuration and an edge represents a physical or logical vulnerability dependency. A node gets compromised if a certain set of its neighbors are compromised. Attack graphs describe explicit scenarios in which a single vulnerability exploitation cascades further into the network exploiting inherent dependencies among the network components. Attack graphs are used for studying cascading effects in many cybersecurity applications, e.g., component failure in enterprise networks, botnet spreads, advanced persistent attacks. One distinct feature of cyber attack cascades is the stealthy nature of the attack moves. Also, cyber attacks are generally repeated. How to control stealthy and repeated attack cascades is an interesting problem. Dijk et. al.~cite{van2013flipit} first proposed a game framework called ``FlipIt" for reasoning about the stealthy interaction between a defender and an attacker over the control of a system resource. However, in cybersecurity applications, systems generally consists of multiple resources connected by a network. Therefore it is imperative to study the stealthy attack and defense in networked systems. We develop a generalized framework called ``FlipNet" which extends the work of Dijk et. al.~cite{van2013flipit} for network. We present analyses and algorithms for different problems in this framework. On the other hand, if the security of a system is limited to the vulnerabilities and exploitations that are known to the security community, often the objective of the system owner is to take cost-effective steps to minimize potential damage in the network. This problem has been formulated in the cybersecurity literature as hardening attack graphs. Several heuristic approaches have been shown in the litrature so far but no algorithmic analysis have been shown. We analyze the inherent vulnerability of the network and present approximation hardening algorithms. / Ph. D.

The purpose of this research was to understand cost containment strategies used by private hospitals under managed care plans and their relationship to quality of care within the South African environment. The data was collected using a questionnaire consisting of closed questions requesting respondents to rate statements about costs and quality of care, as well as open questions for additional information about costs and quality of care. The study found that managed care has the ability to control costs and that hospitals monitor LOS and prescribe generic medication in order to control costs. The study also found that cost control strategies have a negative impact on quality of care and that hospitals place more emphasis on cost control than quality of care. In addition, large hospitals that enjoy high occupancy rates experienced an increase in patient complaints since the introduction of managed care, compared to small and medium hospitals. The study found that managed care has had a better than average impact on controlling costs and a better than average impact in quality reduction, however the correlation between cost control and quality reduction was negative. Finally, the study found that technology has an impact on rising healthcare costs and that any constraints placed on rising costs associated with technology will have a negative impact on quality of care. Copyright / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted

No description available.

No description available.

No description available.

No description available.

The aim of this thesis project has been to explore stages for performance that promotes situational displacement and questions cultural containment and inclusion. By implementing stages that merges with and leaks out in to the surrounding urban environment the aspiration has been to manipulate adjacent urban spaces and by doing so offer an alternative spatial imagination that provokes public consciousness and the possiblity of new subjective and collective engagement within our built environment.