In the paper we describe the problem of grouping and aggregation in the concept-oriented data model. The model is based on ordering its elements within a hierarchical multidimensi...
In heterogeneous data warehousing environments, autonomous data sources are integrated into a materialized integrated database. The schemas of the data sources and the integrated ...
We give two sufficient conditions on XPath like languages for having first order expressivity, meaning that every first order definable set of paths in an ordered node-labeled t...
We give a complexity theoretic classification of homomorphism problems for graphs and, more generally, relational structures obtained by restricting the left hand side structure ...
Web documents present new challenges to conventional Information Retrieval (IR) technologies. This paper describes how these challenges are faced in FameIR, a multilingual multime...