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  • Thesis


  • Authors: Lakhina, Anukool (2006)

  • To attack this problem we adopt the general strategy of seeking low-dimensional approximations that preserve important traffic properties. Our starting point, and the first contribution of this dissertation, is to demonstrate that accurate low-dimensional approximations of network traffic often exist. We show that network-wide traffic measurements that exhibit as many as hundreds of dimensions can be approximated well using a much smaller set of dimensions (for example, less than ten). This observation of low effective dimensionality is key, and provides leverage on a number of problems related to network operations. In particular, low effective dimensionality leads us to make use of subspace methods. These methods systematically exploit the low dimensionality of multi-feature traf...

  • Thesis


  • Authors: Pascu, Stefan (2006)

  • In this thesis we propose a novel way to achieve global network information dissemination in which some wavelengths are reserved exclusively for global control information exchange. We study the routing and wavelength assignment problem for the special communication pattern of non-blocking all-to-all broadcast in WDM optical networks. We provide efficient solutions to reduce the number of wavelengths needed for non-blocking all-to-all broadcast, in the absence of wavelength converters, for network information dissemination. We adopt an approach in which we consider all nodes to be tap-and-continue capable thus studying lighttrees rather than lightpaths. To the best of our knowledge, this thesis is the first to consider “tap-and-continue” capable nodes in the context of conflict-fre...

  • Thesis


  • Authors: Zhu, Ge (2006)

  • Buffer overflow happens when the runtime process loads more data into the buffer than its design capacity. Bad programming style and lack of security concern cause overflow vulnerabilities in almost all applications on all the platforms. As a common vulnerability, buffer overflow accounts for more than 20% of the public vulnerabilities reported in Common Vulnerabilities and Exposures (version 20040901). Buffer overflow attack can target any data in stack or heap. A common target of overflow attack is return address stored in the stack during runtime. By overflowing the return address, the attacker could redirect the program control flow when the current function returns. Many solutions have been proposed to protect return address from being overflowed, like StackGaurd, StackShield ...

  • Thesis


  • Authors: Guirguis, Mina (2006)

  • One important consideration in realizing dependable computing systems and networks is to uncover vulnerabilities in their designs to adversarial attacks. Currently, the designs of these systems employ different forms of adaptation mechanisms in order to optimize their performance by ensuring that desirable properties, such as stability, efficiency and fairness, are not compromised. This thesis discovers and studies a new type of adversarial attacks that target such adaptation mechanisms by exploiting their dynamics of operation - i.e., the characteristics of their transient behavior. We coin this new breed of adversarial attacks, Reduction of Quality (RoQ) attacks. The premise of RoQ attacks is to keep an adaptive mechanism constantly in a transient state, effectively depriving the ...

  • Thesis


  • Authors: Kothapalli, Kishore (2006)

  • In this age of information, new models of information exchange methodologies based on overlay networks are gaining popular attention. Overlay networks provide a logical interconnection topology over an existing physical network. Overlay networks offer bene¬fits such as ease of implementation, flexibility, adaptability, and incremental deployability. Due to the wide range of applications and advantages, formal study of overlay networks is required to understand the various research challenges in this context. In this thesis, we study two classes of overlay networks namely peer-to-peer networks and wireless ad hoc networks. Our focus will be along two central issues in overlay net works: how to arrive at efficient topologies and how to provide efficient routing strategies. Peer-t...