Qucosa - Technische Universität Dresden: Closed-World Semantics for Query Answering in Temporal Description Logics

AutorIn

Walter Forkel

Titel

Closed-World Semantics for Query Answering in Temporal Description Logics

Zitierfähige Url:

https://nbn-resolving.org/urn:nbn:de:bsz:14-qucosa2-737736

Datum der Einreichung

06.10.2020

Datum der Verteidigung

18.12.2020

Abstract (EN)

Ontology-mediated query answering is a popular paradigm for enriching answers to user queries with background knowledge. For querying the absence of information, however, there exist only few ontology-based approaches. Moreover, these proposals conflate the closed-domain and closed-world assumption, and therefore are not suited to deal with the anonymous objects that are common in ontological reasoning. Many real-world applications, like processing electronic health records (EHRs), also contain a temporal dimension, and require efficient reasoning algorithms. Moreover, since medical data is not recorded on a regular basis, reasoners must deal with sparse data with potentially large temporal gaps. Our contribution consists of three main parts: Firstly, we introduce a new closed-world semantics for answering conjunctive queries with negation over ontologies formulated in the description logic ELH⊥, which is based on the minimal universal model. We propose a rewriting strategy for dealing with negated query atoms, which shows that query answering is possible in polynomial time in data complexity. Secondly, we introduce a new temporal variant of ELH⊥ that features a convexity operator. We extend this minimal-world semantics for answering metric temporal conjunctive queries with negation over the logic and obtain similar rewritability and complexity results. Thirdly, apart from the theoretical results, we evaluate minimal-world semantics in practice by selecting patients, based their EHRs, that match given criteria.

Freie Schlagwörter (DE)

Klinische Studien, Temporale Logik, Nicht-Monotones Schlussfolgern

Freie Schlagwörter (EN)

Clinical Trials, Patient Selection, Temporal Logics, Non-Monotonic Reasoning, Closed-World Reasoning

Klassifikation (DDC)

004

Klassifikation (RVK)

ST 640

ST 265

GutachterIn