Complexity of Inconsistency-Tolerant Query Answering in Datalog+/–

Lukasiewicz, Thomas; Martínez, María Vanina; Simari, Gerardo I.

doi:10.1007/978-3-642-41030-7_35

Cited by 22 publications

(18 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, there are two main differences: first, the framework of [73] does not consider valuedomains, hence many of the issues dealt with by our technique are not present in the above Datalog+/-framework; moreover, although identification constraints correspond to EGDs, they are not captured by the restricted form of EGDs (called non-conflicting EGDs) considered in [73]. The work of [73] has been further extended in [74], which presents a set of complexity results about reasoning in Datalog+/-programs under both the IAR-semantics and the ICR-semantics.…”

Section: Instance-level Inconsistency Tolerance In Dlsmentioning

confidence: 94%

Inconsistency-tolerant query answering in ontology-based data access

Lembo

Lenzerini

Rosati

et al. 2015

Journal of Web Semantics

View full text Add to dashboard Cite

a b s t r a c tOntology-based data access (OBDA) is receiving great attention as a new paradigm for managing information systems through semantic technologies. According to this paradigm, a Description Logic ontology provides an abstract and formal representation of the domain of interest to the information system, and is used as a sophisticated schema for accessing the data and formulating queries over them. In this paper, we address the problem of dealing with inconsistencies in OBDA. Our general goal is both to study DL semantical frameworks that are inconsistency-tolerant, and to devise techniques for answering unions of conjunctive queries under such inconsistency-tolerant semantics. Our work is inspired by the approaches to consistent query answering in databases, which are based on the idea of living with inconsistencies in the database, but trying to obtain only consistent information during query answering, by relying on the notion of database repair. We first adapt the notion of database repair to our context, and show that, according to such a notion, inconsistency-tolerant query answering is intractable, even for very simple DLs. Therefore, we propose a different repair-based semantics, with the goal of reaching a good compromise between the expressive power of the semantics and the computational complexity of inconsistency-tolerant query answering. Indeed, we show that query answering under the new semantics is first-order rewritable in OBDA, even if the ontology is expressed in one of the most expressive members of the DL-Lite family.

show abstract

Section: Instance-level Inconsistency Tolerance In Dlsmentioning

confidence: 94%

Inconsistency-tolerant query answering in ontology-based data access

Lembo

Lenzerini

Rosati

et al. 2015

Journal of Web Semantics

View full text Add to dashboard Cite

show abstract

“…However, there are two main differences: first, the framework of [52] does not consider value-domains, hence many of the issues dealt with by our technique are not present in the above Datalog+/framework; moreover, although identification constraints correspond to EGDs, they are not captured by the restricted form of EGDs (called non-conflicting EGDs) considered in [52]. The work of [52] has been further extended in [53], which presents a set of complexity results about reasoning in Datalog+/-programs under both the IAR-semantics and the ICR-semantics.…”

Section: Instance-level Inconsistency Tolerance In Dlsmentioning

confidence: 99%

Inconsistency-Tolerant Query Answering in Ontology-Based Data Access

Lembo¹,

Lenzerini²,

Rosati³

et al. 2015

SSRN Journal

View full text Add to dashboard Cite

Ontology-based data access (OBDA) is receiving great attention as a new paradigm for managing information systems through semantic technologies. According to this paradigm, a Description Logic ontology provides an abstract and formal representation of the domain of interest to the information system, and is used as a sophisticated schema for accessing the data and formulating queries over them. In this paper, we address the problem of dealing with inconsistencies in OBDA. Our general goal is both to study DL semantical frameworks that are inconsistency-tolerant, and to devise techniques for answering unions of conjunctive queries under such inconsistency-tolerant semantics. Our work is inspired by the approaches to consistent query answering in databases, which are based on the idea of living with inconsistencies in the database, but trying to obtain only consistent information during query answering, by relying on the notion of database repair. We first adapt the notion of database repair to our context, and show that, according to such a notion, inconsistency-tolerant query answering is intractable, even for very simple DLs. Therefore, we propose a different repair-based semantics, with the goal of reaching a good compromise between the expressive power of the semantics and the computational complexity of inconsistency-tolerant query answering. Indeed, we show that query answering under the new semantics is first-order rewritable in OBDA, even if the ontology is expressed in one of the most expressive members of the DL-Lite family.The results presented in this paper appeared in preliminary form in [46,47,45]. PreliminariesDescription Logics [5] are decidable fragments of first-order logic (FOL) that can be used to represent the knowledge of a domain of interest in a structured and formally well-understood way. They model the domain of interest in terms of objects, i.e., individuals, concepts, that are abstractions for sets of objects, and roles, that denote binary relations between objects. In addition, some DLs distinguish concepts from value-domains, that denote sets of values, and roles from attributes, that denote binary relations between objects and values.We consider an overall alphabet Γ, partitioned in two disjoint alphabets, namely, Γ P , containing symbols for predicates, and Γ C , containing symbols for individual (object and value) constants. We further partition Γ P into four disjoint sets containing symbols denoting atomic concepts, atomic roles, attributes, and value-domains, respectively, and partition Γ C into two disjoint sets, called Γ O and Γ V , which are the set of constants denoting objects, and the set of constants denoting values, respectively. In the rest of the paper, when it is clear from the context, we often implicitly refer to Γ.Complex concept, role, and attribute expressions are constructed by applying suitable operators to atomic concepts and roles, attributes, and value-domains. Different DL languages allow for different operators in the constructs.Given a DL language L, an L ...

show abstract

“…Consistent query answering was first proposed in [20]. Query answering under various inconsistency-tolerant semantics for ontologies expressed in DL languages has been studied in [21][22][23][24][25][26][27], and in [28][29][30][31] for ontologies expressed by fragments of Datalog+/-. Several notions of maximality for a repair have been considered in [32].…”

Section: Dealing With Incomplete and Inconsistent Datamentioning

confidence: 99%

Evaluating User Behaviour in a Cooperative Environment

Bazzi¹,

Cassavia

Chiggiato³

et al. 2018

Information

View full text Add to dashboard Cite

Big Data, as a new paradigm, has forced both researchers and industries to rethink data management techniques which has become inadequate in many contexts. Indeed, we deal everyday with huge amounts of collected data about user suggestions and searches. These data require new advanced analysis strategies to be devised in order to profitably leverage this information. Moreover, due to the heterogeneous and fast changing nature of these data, we need to leverage new data storage and management tools to effectively store them. In this paper, we analyze the effect of user searches and suggestions and try to understand how much they influence a user’s social environment. This task is crucial to perform efficient identification of the users that are able to spread their influence across the network. Gathering information about user preferences is a key activity in several scenarios like tourism promotion, personalized marketing, and entertainment suggestions. We show the application of our approach for a huge research project named D-ALL that stands for Data Alliance. In fact, we tried to assess the reaction of users in a competitive environment when they were invited to judge each other. Our results show that the users tend to conform to each other when no tangible rewards are provided while they try to reduce other users’ ratings when it affects getting a tangible prize.

show abstract

Complexity of Inconsistency-Tolerant Query Answering in Datalog+/–

Cited by 22 publications

References 20 publications

Inconsistency-tolerant query answering in ontology-based data access

Inconsistency-tolerant query answering in ontology-based data access

Inconsistency-Tolerant Query Answering in Ontology-Based Data Access

Evaluating User Behaviour in a Cooperative Environment

Contact Info

Product

Resources

About