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The use of tabling in logic programming allows bottom-up evaluation to be incorporated in a top-down framework, combining advantages of both. At the engine level, tabling also introduces issues not present in pure top-down evaluation, due to the need for subgoais and answers to access tables during resolution. This article describes the design,(More)
We describe several new bottom-up approaches to problems in role engineering for Role-Based Access Control (RBAC). The salient problems are all NP-complete, even to approximate, yet we find that in instances that arise in practice these problems can be solved in minutes. We first consider role minimization, the process of finding a smallest collection of(More)
Tabled resolution improves eeciency as well as termination properties of logic programs by sharing answer computations across sim-ilar" subgoals. Similarity based on subsumption of subgoals rather than variance i.e., identity modulo variable renaming promotes more aggressive sharing, but requires mechanisms to index answers from dynamically growing sets.(More)
Twenty four patients diagnosed to be suffering from Obsessive Compulsive Neurosis for the first time and individually matched controls were rated on a Life Events Scale. Leyton Obsessional Inventory was also administered to the patients and controls. It was seen that patients had significantly higher scores on life events for a time span of one year prior(More)
—Providers of location-based services seek new methods to authenticate the location of their clients. We propose a novel infrastructure-based solution that provides spontaneous and transaction-oriented mobile device location authentication via an integrated 802.11x wireless access point and 3G femtocell access system. By simply making a voice call while(More)
Recently tuple-at-a-time evaluation strategies have begun receiving renewed attention for in-memory data queries, due to the existence of eecient techniques for their implementation. One such technique, the SLG-WAM, forms the basis of the XSB systemm9]; performance tests indicate it to be an order of magnitude faster than current deductive databases for a(More)