Christopher T Griffin

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Transactions between peers in social networks generate direct reputation (social capital) information. This can be augmented with indirect referrals, on demand or continually, thus giving peers additional information prior to engaging in transactions with others. Despite proposed deterrents such as identity acquisition costs, false referrals through sybil(More)
The sensor network paradigm uses multiple autonomous sensor nodes to cooperatively construct an ad hoc computational entity. The authors have implemented applications using this approach with a network of sensor prototypes. In the paper, entity tracking is described as a two-tier process: (i) clusters of nodes locally estimate parameters used in entity(More)
Autonomous networks of sensor platforms can be designed to interact in dynamic and noisy environments to determine the occurrence of specified transient events that define the dynamic process of interest. For example, a sensor network may be used for battlefield surveillance with the purpose of detecting, identifying, and tracking enemy activity. When the(More)
Social sites frequently ask for rich sets of user identity properties before granting access. Users are given the freedom to fail to respond to some of these requests, or can choose to submit fake identity properties, so as to reduce the risk of identification, surveillance or observation of any kind. However, this freedom has led to serious security and(More)
Markov models are commonly used to analyze real-world problems. Their combination of discrete states and stochastic transitions is suited to applications with deterministic and stochastic components. Hidden Markov models (HMMs) are a class of Markov models commonly used in pattern recognition. Currently, HMMs recognize patterns using a maximum-likelihood(More)
Two-player pursuit-evasion games in the literature typically either assume both players have perfect knowledge of the opponent's positions or use primitive sensing models. This unrealistically skews the problem in favor of the pursuer who needs only maintain a faster velocity at all turning radii. In real life, an evader usually escapes when the pursuer no(More)
The emergence of online social networks and the growing popularity of digital communication has resulted in an increasingly amount of information about individuals available on the Internet. Social network users are given the freedom to create complex digital identities, and enrich them with truthful or even fake personal information. However, this freedom(More)
Cyberbullying is an increasingly prevalent phenomenon impacting young adults. In this paper, we present a study on both detecting cyberbullies in online social networks and identifying the pairwise interactions between users through which the influence of bullies seems to spread. In particular, we investigate the role of user demographics and social network(More)
In this paper, we develop techniques for automated hypothesis-space exploration over data sets that may contain contradictions. To do so, we make use of the equivalence between two formulations: those of first-order predicate logic with prefix modal quantifiers under the finite-model hypothesis and those of mixed-integer linear programming (MILP) problems.(More)