Heinz Schweppe

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While traditional fixed-wired network protocols like 2Phase-Commit guarantee atomicity, we cannot use them in mobile low bandwidth networks where network partitioning, node failure, and message loss may result in blocking. To deploy traditional database applications easily into a mobile environment, there is a demand for a protocol which guarantees an(More)
RDF is the first W3C standard for enriching information resources of the Web with detailed meta data. The semantics of RDF data is defined using a RDF schema. The most expressive language for querying RDF is RQL, which enables querying of semantics. In order to support RQL, a RDF storage system has to map the RDF graph model onto its storage structure.(More)
The high publication rate of scholarly material makes searching and br owsing an inconvenient way to keep oneself up-to-date. Instead of being the active part in information access, researchers want to be notified whenever a new paper in one's research area is published. While more and more publishing houses or portal sites offer notification services this(More)
ion and Decomposition in Interoperable GIS Agn es Voisard Heinz Schweppe Institut f ur Informatik Freie Universitat Berlin Takustr. 9 D-14195 Berlin fvoisard,schweppeg@inf.fu-berlin.de Abstract With the advent of distributed computing and the increasing trend towards the reuse of geographic data, a new generation of geographic information systems (GIS) is(More)
Service oriented computing provides suitable means to technically support distributed collaboration of heterogeneous devices such as in mobile environments. However, wireless communication links are unstable. When supporting collaboration in such environments, failures have to be optimistically coped with in order to still provide suitable correctness(More)
The classical paradigm of nding information in the WWW by initiating retrieval and browsing becomes more and more ineeective. Other techniques in the context of digital libraries have to be considered. Automatic delivery of contents to the user according to her needs and ltered by her proole of interests is required. Current implementations of such alerting(More)