Özgür L. Özçep

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The paper contributes to the recent efforts on temporalizing and streamifiying ontology based data access (OBDA) by discussing aspects of rewritability, i.e., compilability of the TBox into ontology-level queries, and unfoldability, i.e., transformability of ontology-level queries to queries on datasource level, for the new query-language framework STARQL.(More)
We present a description and analysis of the data access challenge in the Siemens Energy. We advocate for Ontology Based Data Access (OBDA) as a suitable Semantic Web driven technology to address the challenge. We derive requirements for applying OBDA in Siemens, review existing OBDA systems and discuss their limitations with respect to the Siemens(More)
Ontology-based query answering has to be supported w.r.t. secondary memory and very expressive ontologies to meet practical requirements in some applications. Recently, advances for the expressive DL SHI have been made in the dissertation of S. Wandelt for conceptbased instance retrieval on Big Data descriptions stored in secondary memory. In this paper we(More)
First order logic (FOL) rewritability is a desirable feature for query answering over geo-thematic ontologies because in most geoprocessing scenarios one has to cope with large data volume. Hence, there is a need for combined geo-thematic logics that provide a sufficiently expressive query language allowing for FOL rewritability. The DL-Lite family of(More)
Rational agents perceiving data from a dynamic environment and acting in it have to be equipped with capabilities such as decision making, planning etc. We assume that these capabilities are based on query answering with respect to (high-level) streams of symbolic descriptions, which are grounded in (low-level) data streams. Queries need to be answered(More)
6 Scalable End-user Access to Big Data 1 6.1 The Data Access Problem of Big Data . . . . . . . . . . . . . . . . . . . . . 2 6.2 Ontology-Based Data Access . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.2.1 Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.2.2 Limitations of the State of the Art in OBDA . . . . . . .(More)
Despite the dramatic growth of data accumulated by enterprises, obtaining value out of it is extremely challenging. In particular, the data access bottleneck prevents domain experts from getting the right piece of data within a constrained time frame. The Optique Platform unlocks the access to Big Data by providing end users support for directly formulating(More)