2 citations · 2 across the 6 of their papers we have counts for
6 papers · 1 filter
Tight Lower Bounds for Query Processing on Streaming and External Memory Data
Martin Grohe, Christoph Koch, Nicole Schweikardt
We study a clean machine model for external memory and stream processing. We show that the number of scans of the external data induces a strict hierarchy (as long as work space is…
On the Complexity of Nonrecursive XQuery and Functional Query Languages on Complex Values
Christoph Koch
This paper studies the complexity of evaluating functional query languages for complex values such as monad algebra and the recursion-free fragment of XQuery. We show that monad al…
Schema-based Scheduling of Event Processors and Buffer Minimization for Queries on Structured Data Streams
Christoph Koch, Stefanie Scherzinger, Nicole Schweikardt +1
We introduce an extension of the XQuery language, FluX, that supports event-based query processing and the conscious handling of main memory buffers. Purely event-based queries of…
A Formal Comparison of Visual Web Wrapper Generators
Georg Gottlob, Christoph Koch
We study the core fragment of the Elog wrapping language used in the Lixto system (a visual wrapper generator) and formally compare Elog to other wrapping languages proposed in the…
Monadic Datalog and the Expressive Power of Languages for Web Information Extraction
Georg Gottlob, Christoph Koch
Research on information extraction from Web pages (wrapping) has seen much activity recently (particularly systems implementations), but little work has been done on formally study…
Optimizing Queries Using a Meta-level Database
Christoph Koch
Graph simulation (using graph schemata or data guides) has been successfully proposed as a technique for adding structure to semistructured data. Design patterns for description (s…