Auflistung nach Autor:in "Voigt, Hannes"
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- KonferenzbeitragAnfragegetriebene Indizierung räumlicher Daten(Informatik 2009 – Im Focus das Leben, 2009) Voigt, Hannes; Preißler, Steffen; Böhm, Matthias; Lehner, Wolfgang
- KonferenzbeitragEin begriffsbasierter Ansatz zur semantischen Extraktion von Datenbankschemata(Software Engineering 2010 – Workshopband (inkl. Doktorandensymposium), 2010) Mühle, Henri; Voigt, Hannes; Lehner, WolfgangDie durch das rasante Anwachsen digitaler Datenbestände in Volumen und Vielfalt notwendig gewordene effiziente Verwaltung der erhobenen Datenbestände, bringt herkömmliche Datenbankmethoden an ihre Grenzen. Ein modelliertes Datenbankschema zur Grundstrukturierung der Datenbank kann längst nicht mehr statisch rigide modelliert werden. Vielmehr werden schemaflexible Datenbanken benötigt, die ihr Schema entsprechend an Änderungen im Datenbestand anpassen können. Da das Datenbankschema basierend auf einer konzeptuellen Datenbanksicht modelliert wird, präsentieren wir einen Ansatz, der die Formale Begriffsanalyse als Modellierungsmethode einsetzt. Die Formale Begriffsanalyse greift genau diese begriffsorientierte Weltsicht auf. Damit können wir Schemaextraktion und weiterführende Problemstellungen mit wohl verstandenen und gut untersuchten Mechanismen behandeln. Im Rahmen dieses Beitrages stellen wir ein begriffsbasiertes Verfahren zur Schemaextraktion vor, das sich genau diese konzeptuelle Weltsicht zu Nutze macht.
- ZeitschriftenartikelBig Graph Data Analytics on Single Machines – An Overview(Datenbank-Spektrum: Vol. 17, No. 2, 2017) Paradies, Marcus; Voigt, HannesDriven by a multitude of use cases, graph data analytics has become a hot topic in research and industry. Particularly on big graphs, performing complex analytical queries efficiently to derive new insights is a challenging task. Systems that aim at solving the technical part of this challenge are often referred to as graph processing systems. They allow expressing and executing analytic algorithms and queries, while hiding most of the technical details related to efficiently storing and processing graph data. Since 2010, work on graph processing systems for distributed systems as well as shared memory systems has virtually exploded. In this article, we give an overview of this work with the particular focus on graph processing systems for large multiprocessor machines. We describe the state of the art established in recent years and outline trends and challenges in research and development that point towards the future of graph processing systems.
- ZeitschriftenartikelEditorial(Datenbank-Spektrum: Vol. 17, No. 2, 2017) Voigt, Hannes; Paradies, Marcus; Härder, Theo
- KonferenzbeitragInVerDa – The Liquid Database(Datenbanksysteme für Business, Technologie und Web (BTW 2017), 2017) Herrmann, Kai; Voigt, Hannes; Seyschab, Thorsten; Lehner, WolfgangMultiple applications, which share one common database, will evolve over time by their very nature. Often, former versions need to stay available, so database developers find themselves maintaining co-existing schema versions of multiple applications in multiple versions—usually with handwritten delta code—which is highly error-prone and explains significant costs in software projects. We showcase I V D , a tool using the richer semantics of a bidirectional database evolution language to generate all the delta code automatically, easily providing co-existing schema versions within one database. I V D automatically decides on an optimized physical database schema serving all schema versions to transparently optimize the performance for the current workload.
- KonferenzbeitragMOAW: an agile visual modeling and exploration tool for irregularly structured data(Datenbanksysteme für Business, Technologie und Web (BTW), 2011) Werner, Horst; Bornhoevd, Christof; Kubis, Robert; Voigt, HannesThe Mother of all Whiteboards (MOAW) is an innovative visual modeling and exploration tool for semi-structured information. It combines gesture-based user interaction with deep zooming, particle dynamics and the powerful data processing capabilities of SAP's newly developed Active Information Store. This application has been designed to convey complex information by easily created visual models which are backed by a formal representation and thus allow the fluid navigation to unlimited levels of detail and creation of different angles of view.
- KonferenzbeitragPack indexing for time-constrained in-memory query processing(Datenbanksysteme für Business, Technologie und Web (BTW) 2023, 2013) Jaekel, Tobias; Voigt, Hannes; Kissinger, Thomas; Lehner, WolfgangMain memory databases management systems are used more often and in a wide spread of application scenarios. To take significant advantage of the main memory read performance, most techniques known from traditional disk-centric database systems have to be adapted and re-designed. In the field of indexing, many mainmemory-optimized index structures have been proposed. Most of these works aim at primary indexing. Secondary indexes are rarely considered in the context of main memory databases. Either query performance is sufficiently good without secondary indexing or main memory is a resource too scarce to invest in huge secondary indexes. A more subtle trade between benefit and costs of secondary indexing has not been considered so far. In this paper we present Pack Indexing, a secondary indexing technique for main memory databases that allows a precise trade-off between the benefit in query execution time gained with a secondary index and main memory invested for that index. Compared to traditional indexing, Pack Indexing achieves this by varying the granularity of indexing. We discuss the Pack Indexing concept in detail and describe how the concept can be implemented. To demonstrate the usefulness and the effectiveness of our approach, we present several experiments with different datasets.
- KonferenzbeitragRelationships for dynamic data types in RSQL(Datenbanksysteme für Business, Technologie und Web (BTW 2015), 2015) Jäkel, Tobias; Kühn, Thomas; Hinkel, Stefan; Voigt, Hannes; Lehner, WolfgangCurrently, there is a mismatch between the conceptual model of an information system and its implementation in a database management system (DBMS). Most of the conceptual modeling languages relate their conceptual entities with relationships, but relational database management systems solely rely on the notion of relations to model both, entities and relationships. To make things worse, real world objects are not static as assumed in such modeling languages, but change over time. Thus, modeling languages were enriched to model those scenarios, as well. However, mapping these models onto relational databases requires the use of object-relational mapping engines, which in turn hide the semantics of the conceptual model from the DBMS. Consequently, traditional relational database systems cannot directly ensure specific consistency constraints and thus lose their meaning as single point of truth for highly distributed information systems. To overcome these issues we have proposed RSQL, a data model and query language introducing role-based data structures in DBMSs. Despite the fact that RSQL is able to handle complex objects, it does not support relationships between those objects. Therefore, this work adds relationships to RSQL by augmenting the data model and extending its query language. As a result, this extension allows for the direct representation of conceptual models with complex objects and relationships in the DBMS. Thus, relationships can be directly addressed in queries and the DBMS automatically ensures relationship consistency constraints as well as cardinality. In sum, a DBMS equipped with the extended RSQL is apt for storing and querying conceptual models and thus regains its rightful position as the single point of truth for highly distributed information systems.
- KonferenzbeitragSPARQLytics: Multidimensional Analytics for RDF(Datenbanksysteme für Business, Technologie und Web (BTW 2017), 2017) Rudolf, Michael; Voigt, Hannes; Lehner, WolfgangWith the rapid growth of open RDF data in recent years, being able to perform multidimensional analytics with it has become more and more important, in particular for the data analyst performing explorative business intelligence tasks. Existing analytic approaches are often not flexible enough to address the needs of data analysts and enthusiasts with iterative exploratory workflows. In this paper we propose SPARQLytics, a tool that exposes the concepts of multidimensional graph analytics by offering standard OLAP cube operations and generating SPARQL queries. Our evaluation shows that SPARQLytics unburdens data analysts from writing many lines of SPARQL code in iterative data explorations and at the same time it does not impose any overhead to query execution. SPARQLytics fits well with interactive computing tools, such as Jupyter, providing data enthusiasts with a familiar work environment.
- KonferenzbeitragStream-based web service invocation(Datenbanksysteme in Business, Technologie und Web (BTW) – 13. Fachtagung des GI-Fachbereichs "Datenbanken und Informationssysteme" (DBIS), 2009) Preißler, Steffen; Voigt, Hannes; Habich, Dirk; Lehner, WolfgangService-oriented architectures (SOA) based on Web service technology play an increasingly important role in many different application areas. The current service invocation methodology suffers from performance problems and heavy resource consumption when