Jonathan Traupman

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Network applications of the future will require advanced mechanisms for automatic failure recovery in order to provide an acceptable quality of service. Because of this requirement , there is a need for tools that can inject simulated faults to verify a system's fault detection and recovery methods. We present a set of objectives that such a fault injection(More)
We describe LASER, a scalable response prediction platform currently used as part of a social network advertising system. LASER enables the familiar logistic regression model to be applied to very large scale response prediction problems, including ones beyond advertising. Though the underlying model is well understood, we apply a whole-system approach to(More)
We have developed EM-trust, a robust algorithm for evaluating reputations in peer-to-peer marketplaces. EM-trust is robust in the sense that it is far less susceptible than are previous algorithms to errors due to inaccurate feedback. Moreover, a Bayesian version of EM-trust seems ideally suited to real peer-to-peer marketplaces, in which participants are(More)
Most contemporary software applications presuppose an error-free system environment. While this assumption is often correct, the system can break down under exceptional situations, such as resource exhaustion or network failures. Unfortunately, too few developers deal with these issues, since they rarely arise in normal testing scenarios and are usually(More)
We describe two techniques for reducing the effectiveness of sybil attacks, in which an attacker uses a large number of fake user accounts to increase his reputation. The first technique uses a novel transformation of the ranks returned by the PageRank system. This transformation not only reduces susceptibility to sybil attacks but also provides an(More)
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