scholarly journals Revisiting Controlled Query Evaluation in Description Logics

2019 ◽  
Author(s):  
Domenico Lembo ◽  
Riccardo Rosati ◽  
Domenico Fabio Savo
Keyword(s):  
Private Information ◽  
Description Logics ◽  
Study Data ◽  
Query Answering ◽  
Query Evaluation ◽  
Data Complexity ◽  
Complexity Results ◽  
Controlled Query Evaluation ◽  
Consistent Query Answering ◽  
The Relationship

Controlled Query Evaluation (CQE) is a confidentiality-preserving framework in which private information is protected through a policy, and a (optimal) censor guarantees that answers to queries are maximized without violating the policy. CQE has been recently studied in the context of ontologies, where the focus has been mainly on the problem of the existence of an optimal censor. In this paper we instead consider query answering over all possible optimal censors. We study data complexity of this problem for ontologies specified in the Description Logics DL-LiteR and EL_bottom and for variants of the censor language, which is the language used by the censor to enforce the policy. In our investigation we also analyze the relationship between CQE and the problem of Consistent Query Answering (CQA). Some of the complexity results we provide are indeed obtained through mutual reduction between CQE and CQA.

scholarly journals Controlled Query Evaluation in Description Logics Through Instance Indistinguishability

2020 ◽  
Author(s):  
Gianluca Cima ◽  
Domenico Lembo ◽  
Riccardo Rosati ◽  
Domenico Fabio Savo
Keyword(s):  
Description Logics ◽  
Privacy Preserving ◽  
Query Answering ◽  
Query Evaluation ◽  
Data Complexity ◽  
First Order ◽  
Complexity Results ◽  
Controlled Query Evaluation

We study privacy-preserving query answering in Description Logics (DLs). Specifically, we consider the approach of controlled query evaluation (CQE) based on the notion of instance indistinguishability. We derive data complexity results for query answering over DL-LiteR ontologies, through a comparison with an alternative, existing confidentiality-preserving approach to CQE. Finally, we identify a semantically well-founded notion of approximated query answering for CQE, and prove that, for DL-LiteR ontologies, this form of CQE is tractable with respect to data complexity and is first-order rewritable, i.e., it is always reducible to the evaluation of a first-order query over the data instance.

scholarly journals Inconsistency-Tolerant Ontology-Based Data Access Revisited: Taking Mappings into Account

2018 ◽  
Author(s):  
Meghyn Bienvenu
Keyword(s):  
Detailed Analysis ◽  
Description Logics ◽  
Data Access ◽  
Query Answering ◽  
Symmetric Difference ◽  
Relational Data ◽  
Data Complexity

Inconsistency-tolerant query answering in the presence of ontologies has received considerable attention in recent years. However, existing work assumes that the data is expressed using the vocabulary of the ontology and is therefore not directly applicable to ontology-based data access (OBDA), where relational data is connected to the ontology via mappings. This motivates us to revisit existing results in the wider context of OBDA with mappings. After formalizing the problem, we perform a detailed analysis of the data complexity of inconsistency-tolerant OBDA for ontologies formulated in DL-Lite and other data-tractable description logics, considering three different semantics (AR, IAR, and brave), two notions of repairs (subset and symmetric difference), and two classes of global-as-view (GAV) mappings. We show that adding plain GAV mappings does not affect data complexity, but there is a jump in complexity if mappings with negated atoms are considered.

scholarly journals Data complexity of query answering in description logics

2013 ◽  
Vol 195 ◽  
pp. 335-360 ◽  
Author(s):  
Diego Calvanese ◽  
Giuseppe De Giacomo ◽  
Domenico Lembo ◽  
Maurizio Lenzerini ◽  
Riccardo Rosati
Keyword(s):  
Description Logics ◽  
Query Answering ◽  
Data Complexity

On the Data Complexity of Consistent Query Answering

2014 ◽  
Vol 57 (4) ◽  
pp. 843-891 ◽  
Author(s):  
Balder ten Cate ◽  
Gaëlle Fontaine ◽  
Phokion G. Kolaitis
Keyword(s):  
Query Answering ◽  
Data Complexity ◽  
Consistent Query Answering

scholarly journals Data Complexity of Query Answering in Expressive Description Logics via Tableaux

2008 ◽  
Vol 41 (1) ◽  
pp. 61-98 ◽  
Author(s):  
Magdalena Ortiz ◽  
Diego Calvanese ◽  
Thomas Eiter
Keyword(s):  
Description Logics ◽  
Query Answering ◽  
Data Complexity

scholarly journals Query answering in circumscribed OWL2 profiles

2021 ◽  
Author(s):  
Piero A. Bonatti
Keyword(s):  
Description Logics ◽  
Knowledge Bases ◽  
Query Answering ◽  
Data Complexity ◽  
Conjunctive Query ◽  
Conjunctive Queries

AbstractThis paper partially bridges a gap in the literature on Circumscription in Description Logics by investigating the tractability of conjunctive query answering in OWL2’s profiles. It turns out that the data complexity of conjunctive query answering is coNP-hard in circumscribed $\mathcal {E}{\mathscr{L}}$ E L and DL-lite, while in circumscribed OWL2-RL conjunctive queries retain their classical semantics. In an attempt to capture nonclassical inferences in OWL2-RL, we consider conjunctive queries with safe negation. They can detect some of the nonclassical consequences of circumscribed knowledge bases, but data complexity becomes coNP-hard. In circumscribed $\mathcal {E}{\mathscr{L}}$ E L , answering queries with safe negation is undecidable.

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