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Auflistung nach Autor:in "Herschel, Sven"

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  • Konferenzbeitrag
    Goya - Vom Programmierwettbewerb zum Verwaltungssystem
    (INFORMATIK 2003 – Innovative Informatikanwendungen, Band 2, Beiträge der 33. Jahrestagung der Gesellschaft für Informatik e.V. (GI), 2003) Herschel, Sven
    Entstanden im Rahmen eines Programmierwettbewerbes am In- stitut für Informatik der Humboldt-Universität zu Berlin, entwickelte sich das studentische Verwaltungssystem "Goya" schnell zur Standardplattform im universitären Übungsbetrieb des Instituts. Dieser Beitrag beschäftigt sich mit der Entstehung des Systems im Rahmen des Wettbewerbs, den Grundprinzipien, die ihm zugrunde liegen, seiner Funktionalität sowie den Erfahrungen, die mit dem System gesammelt wurden.
  • Konferenzbeitrag
    Indexing dynamic networks
    (Informatk 2005. Informatik Live! Band 1, 2005) Herschel, Sven
    While Peer-To-Peer (P2P) networks have evolved largely outside the academic community, they became increasingly popular with computer science researchers lately due to their compelling properties like robustness, scalability and resistance to failure. Due to lack of centralized control a major problem in any P2P system is the location of suitable information sources, a problem especially challenging in dynamic scenarios, where nodes join and leave the network regularly. In order to meet these challenges we developed an architecture for query processing which we call “The Query Web”, based on a hybrid P2P index combining a distributed hash table approach with an unstructured P2P network. By assigning the high-level indexing task to the reliable nodes in the P2P network, we expect the index to be reasonably insensitive to both changes of the network structure as well as updates of the data instances.
  • Konferenzbeitrag
    Self-extending peer data management
    (Datenbanksysteme in Business, Technologie und Web, 11. Fachtagung des GIFachbereichs “Datenbanken und Informationssysteme” (DBIS), 2005) Heese, Ralf; Herschel, Sven; Naumann, Felix; Roth, Armin
    Peer data management systems (PDMS) are the natural extension of integrated information systems. Conventionally, a single integrating system manages an integrated schema, distributes queries to appropriate sources, and integrates incoming data to a common result. In contrast, a PDMS consists of a set of peers, each of which can play the role of an integrating component. A peer knows about its neighboring peers by mappings, which help to translate queries and transform data. Queries submitted to one peer are answered by data residing at that peer and by data that is reached along paths of mappings through the network of peers. The only restriction for PDMS to cover unbounded data is the need to formulate at least one mapping from some known peer to a new data source. We propose a Semantic Web based method that overcomes this restriction, albeit at a price. As sources are dynamically and automatically included in a PDMS, three factors diminish quality: The new source itself might store data of poor quality, the mapping to the PDMS might be incorrect, and the mapping to the PDMS might be incomplete. To compensate, we propose a quality model to measure this effect, a cost model to restrict query planning to the best paths through the PDMS, and techniques to answer queries in such Webscale PDMS efficiently.