Giora Slutzki

Package-Based Description Logics

We present the syntax and semantics of a family of modular ontology languages, Package-based Description Logics (P-DL), to support context- specific reuse of knowledge from multiple ontology modules. In particular, we describe a P-DL

Privacy-Preserving Reasoning on the SemanticWeb

{\mathcal SHOIQP}

Ranking participants in generalized tournaments

that allows the importing of concept, role and nominal names between multiple ontology modules (each of which can be viewed as a

Pursuit-evasion using beam detection

{\mathcal SHOIQ}

Using sparsification for parametric minimum spanning tree problems

ontology).

Complexity of Some Problems Concerning Varieties and Quasi-Varieties of Algebras

{\mathcal SHOIQP}

Multi-valued logic programming semantics: an algebraic approach

supports contextualized interpretation, i.e., interpretation from the point of view of a specific package. We establish the necessary and sufficient conditions on domain relations (i.e., the relations between individuals in different local domains) that need to hold in order to preserve the unsatisfiability of concept formulae, monotonicity of inference, transitive reuse of knowledge across modules.

COMPUTATIONAL COMPLEXITY OF TERM-EQUIVALENCE

Many semantic web applications require selective sharing of ontologies between autonomous entities due to copyright, privacy or security concerns. In such cases, an agent might want to hide a part of its ontology while sharing the rest. However, prohibiting any use of the hidden part of the ontology in answering queries from other agents may be overly restrictive. We provide a framework for privacy- preserving reasoning in which an agent can safely answer queries against its knowledge base using inferences based on both the hidden and visible part of the knowledge base, without revealing the hidden knowledge. We show an application of this framework in the widely used special case of hierarchical ontologies.In this paper, we discover the changes of students’ learning interest from their usage data in web-based learning environment. Due to the effects on each other of the changes in web students and web lectures, we seek a method that integrates the changes in both sides to measure the changes of learning interest. We implement our work on our webbased learning environment: tele-TASK. The mined results help teachers to know their students clearly and adjust their teaching schedules efficiently.

CLEARING A POLYGON WITH TWO 1-SEARCHERS

Consider the problem of ranking social alternatives based on the number of voters that prefer one alternative to the other. Or consider the problem of ranking chess players by their past performance. A wide variety of ranking methods have been proposed to deal with these problems. Using six independent axioms, we characterize the fair-bets ranking method proposed by Daniels [4] and Moon and Pullman [14].

Parametric multiple sequence alignment and phylogeny construction

We present an algorithm for searching a 2D environment for unpredictable moving targets using only beam-based detection. One or more pursuers move along the environment boundary, and carry a rotating beam that detects evaders. The beam could correspond in practice to a laser or a camera. The task is to compute motions for pursuers and their beams that ensure that all evaders will be detected. For a 2D polygonal environment, we solve a long-standing open problem by presenting a complete O(n/sup 3/)-time algorithm that is guaranteed to find a successful motion strategy for a single pursuer and its beam, if a solution exists. This algorithm is extended to the case of coordinating multiple pursuers, but the number of pursuers used in a solution is not necessarily optimal. An implementation is presented, and several computed examples are shown.