Top-k Retrieval in Description Logic Programs Under Vagueness for the Semantic Web

Abstract

Abstract. Description logics (DLs) and logic programs (LPs) are important representation languages for the Semantic Web. In this paper, we address an emerging problem in such languages, namely, the problem of evaluating ranked top-k queries. Specifically, we show how to compute the top-k answers in a datacomplexity tractable combination of DLs and LPs under vagueness.

Fuzzy matchmaking in e-marketplaces of peer entities using Datalog

“…We extend it by allowing soft constraint predicates to appear in rules and queries (we call the language Top-k-Datalog). The proposal here extends the work [35] in which soft constraint predicates, i.e., fuzzy predicates, may appear in queries only and is conceptually equivalent to [23,36]. Basically, we allow vague/fuzzy predicates to occur in rule bodies, which have the effect that each tuple in the answer set of a query has a score in [0,1].…”

“…Observe that b and v 3 are variables, that can unify only with a buyer and a seller, respectively, due to the new definitions (22)(23) of Buyer and Seller. Now we can have two matchmaking services in the marketplace.…”

Fuzzy Methods on the Web: A Critical Discussion

“…Sound and complete reasoning procedures were introduced in [100] for a basic fuzzy description logic and a particular choice for the fuzzy logic connectives. More recently, among others, more expressive description logics have been considered [97,99], larger classes of fuzzy logic connectives [37], and more complex reasoning tasks [54]. Of particular interest are fuzzy description logics with concrete domains [101], which allow to explicitly define fuzzy predicates which can then be used in the definition of concepts.…”

Semantic-Based Top-k Retrieval for Competence Management

“…The logic extends DLR-Lite by enriching it with built-in predicates. Conjunctive queries are enriched with scoring functions that allow to rank and retrieve the top-k answers, that is, we support Top-k Query Answering [14,17,18,19,20], (find top-k scored tuples satisfying query), e.g., "find candidates with excellent knowledge in DLR-Lite", where EXCELLENT is a function of the years of experience.…”