Cooperative localization for mobile agents: a recursive decentralized algorithm based on Kalman filter decoupling

We consider cooperative localization technique for mobile agents with communication and computation capabilities. We start by provide and overview of different decentralization strategies in the literature, with special focus on how these algorithms maintain an account of intrinsic correlations between state estimate of team members. Then, we present a novel decentralized cooperative localization algorithm that is a decentralized implementation of a centralized Extended Kalman Filter for cooperative localization. In this algorithm, instead of propagating cross-covariance terms, each agent propagates new intermediate local variables that can be used in an update stage to create the required propagated cross-covariance terms. Whenever there is a relative measurement in the network, the algorithm declares the agent making this measurement as the interim master. By acquiring information from the interim landmark, the agent the relative measurement is taken from, the interim master can calculate and broadcast a set of intermediate variables which each robot can then use to update its estimates to match that of a centralized Extended Kalman Filter for cooperative localization. Once an update is done, no further communication is needed until the next relative measurement

A Macroscopic Study of Network Security Threats at the Organizational Level.

Defenders of today's network are confronted with a large number of malicious activities such as spam, malware, and denial-of-service attacks. Although many studies have been performed on how to mitigate security threats, the interaction between attackers and defenders is like a game of Whac-a-Mole, in which the security community is chasing after attackers rather than helping defenders to build systematic defensive solutions. As a complement to these studies that focus on attackers or end hosts, this thesis studies security threats from the perspective of the organization, the central authority that manages and defends a group of end hosts. This perspective provides a balanced position to understand security problems and to deploy and evaluate defensive solutions. This thesis explores how a macroscopic view of network security from an organization's perspective can be formed to help measure, understand, and mitigate security threats. To realize this goal, we bring together a broad collection of reputation blacklists. We first measure the properties of the malicious sources identified by these blacklists and their impact on an organization. We then aggregate the malicious sources to Internet organizations and characterize the maliciousness of organizations and their evolution over a period of two and half years. Next, we aim to understand the cause of different maliciousness levels in different organizations. By examining the relationship between eight security mismanagement symptoms and the maliciousness of organizations, we find a strong positive correlation between mismanagement and maliciousness. Lastly, motivated by the observation that there are organizations that have a significant fraction of their IP addresses involved in malicious activities, we evaluate the tradeoff of one type of mitigation solution at the organization level --- network takedowns.PhDComputer Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/116714/1/jingzj_1.pd

The Effect of Defense R&D on Military Capability and Technological Spillover

Generally, the purpose of defense research and development (R&D) is to expand military capability for the armed forces of a country. Any spin-off of technologies from defense R&D programs is usually not a prime motivation but more often an unintended consequence. Nevertheless, many of the technologies used in civilian life were initially research and development projects for military purposes. These technologies eventually become adapted to civilian applications since they had beneficial economic and social \u27\u27spillover\u27\u27 effects. However, there is a lack of research measuring the final outputs of defense R&D, including technology \u27\u27spin-offs.\u27\u27 This study mainly tried to understand the effect of defense R&D expenditures on military capability and technological spillover. Statistical measures such as correlations were used to understand these effects. The study revealed that there is a highly positive correlation between defense R&D expenditure and military capability, as well as between defense R&D expenditure and technological spillover index. The study contributed to the academic literature in three ways by providing: new measures of military capability, a new estimation method for defense R&D expenditures, and a new method to measure technological spillover effect from defense R&D expenditures

Factors and Interactions That Affect Air Force C-17 Aircraft Mission Capable Rates

Given the high demand for mission capable airlift aircraft and considering increasing budget pressures, Air Mobility Command decision makers need a better understanding of mission capable (MC) rate-related factors and their interactions for mobility aircraft. This is needed to comprehend how issues such as airlift funding, current and future force reductions, and manning and experience levels may impact future MC rates for air mobility assets. Existing tools do not incorporate several key variables that the literature suggests are related to MC rates. Using a longitudinal approach, this thesis combines C-17 aircraft data with a structural equations modeling approach to evaluate relationships between MC rates and selected variables. The research addresses linkages between several areas not addressed in prior research and currently used models, and provides recommendations for both existing tools and for further research