Computer attackers frequently relay their attacks through a compromised host at an innocent site, thereby obscuring the true origin of the attack. There is a growing literature on ways to detect that an interactive connection into a site and another outbound from the site give evidence of such a “stepping stone.” This has been done based on monitoring the access link connecting the site to the ...

SAT (Boolean satisfiability) has become the primary Boolean reasoning engine for many EDA applications, so the efficiency of SAT solving is of great practical importance. Recently, Goldberg et al. introduced supercubing, a different approach to search-space pruning that unifies many existing methods. Their implementation reduced the number of decisions, but no speedup was obtained. In this pape...

We propose a variable ordering heuristic for SAT, which is based on a structural analysis of the SAT problem. We show that when the heuristic is used by a Davis-Putnam SAT solver that employs conflict-directed backtracking, it produces a divide-and-conquer behavior in which the SAT problem is recursively decomposed into smaller problems that are solved independently. We discuss the implications...

Recent work has shown how to use OBDDs for satisfiability solving. The idea of this approach, which we call symbolic quantifier elimination, is to view an instance of propositional satisfiability as an existentially quantified propositional formula. Satisfiability solving then amounts to quantifier elimination; once all quantifiers have been eliminated we are left with either 1 or 0. Our goal i...

We present a new approach to SAT solvers, supporting efficient implementation of highly sophisticated search heuristics over a range of propositional inputs, including CNF formulas, but particularly BDDs. The approach memoizes search information using a new form of lookahead, called local-functioncomplete lookahead, during an extensive preprocessing phase; we expect to do further experimentatio...

Within the millions of digital communications posted in online social networks, there is undoubtedly some valuable and useful information. Although a large portion of social media content is considered to be babble, research shows that people share useful links, provide recommendations to friends, answer questions, and solve problems. In this paper, we report on a qualitative investigation into...

We address the problem of ranking relationships in an automatically constructed knowledge graph. We propose a probabilistic ranking mechanism that utilizes entity popularity, entity affinity, and support from text corpora for the relationships. Results obtained from preliminary experiments on a standard dataset are encouraging and show that our proposed ranking mechanism can find more informati...