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  • Thesis

  • Authors: Gowing, Glyn Thomas (2007)

  • Computer networks continue to be the targets of numerous types of attacks, which can expose sensitive data or simply deny service to legitimate users. Current intrusion detection technologies utilize signature bases that allow them to rapidly and accurately identify known attacks. This, however, leaves them vulnerable to previously unknown attacks. An adaptive approach, capable of recognizing novel attacks, is warranted. The proposed research presents an adaptive agent-based intrusion detection sys¬tem. The approach is innovative in several respects: the agents self-organize into a scale-free peer-to-peer network, emergent behavior is facilitated by allowing simple communication between the agents, and the system is adaptive both to recognize new attacks and to the loss of agents, ...

  • Thesis

  • Authors: Boicu, Cristina E. (2007)

  • Our research addresses the problem of developing knowledge-based agents that incorporate the knowledge of subject matter experts. Our approach is to develop a learning and problem solving agent, which can be directly taught by a subject matter expert by explaining it how to solve specific problems, and by critiquing its attempts to solve new problems. Because the accuracy of the agent's reasoning depends on the rules from its knowledge base, the process of rule improvement is very important. This dissertation presents an integrated set of methods to assist a subject matter expert in refining the rules from an agent's knowledge base, to incorporate his problem solving expertise. This dissertation presents methods to discover incompletely refined rules and to propose suggestions for t...

  • Thesis

  • Authors: Hà, Tùng Anh. (2007)

  • Due to degradation during aging, most elastomers lose their particularly high extensibility as well as their ability to completely recover after deformation. In this study, the effect of thermo-oxidative aging on mechanical behaviors was investigated for neoprene (polychloroprene rubber). The results from tensile tests have shown that thermal aging resulted in an increase in crosslink density, tensile stress and modulus, as well as a decrease in ultimate elongation. The tensile stress-strain relationship at large strain obeys the eight-chains model. However, Mooney-Rivlin equation shows the best fit for the experimental data in the range of moderate strain and its parameters dependence on aging could be predicted using Arrhenius-type kinetic relation. With prolonged aging or/and at...