The LNCS journal Transactions on Large-Scale Data- and
Knowledge-Centered Systems focuses on data management, knowledge
discovery, and knowledge processing, which are core and hot topics in
computer science. Since the 1990s, the Internet has become the main
driving force behind application development in all domains. An increase
in the demand for resource sharing across different sites connected
through networks has led to an evolution of data- and
knowledge-management systems from centralized systems to decentralized
systems enabling large-scale distributed applications providing high
scalability. Current decentralized systems still focus on data and
knowledge as their main resource. Feasibility of these systems relies
basically on P2P (peer-to-peer) techniques and the support of agent
systems with scaling and decentralized control. Synergy between Grids,
P2P systems, and agent technologies is the key to data- and
knowledge-centered systems in large-scale environments. This special
issue of Transactions on Large-Scale Data- and Knowledge-Centered
Systems highlights some of the major challenges emerging from the
biomedical applications that are currently inspiring and promoting
database research. These include the management, organization, and
integration of massive amounts of heterogeneous data; the semantic gap
between high-level research questions and low-level data; and privacy
and efficiency. The contributions cover a large variety of biological
and medical applications, including genome-wide association studies,
epidemic research, and neuroscience.