This special issue of TLDKS contains two kinds of papers. First, it contains a sel- th tion of the best papers from the 11 International Conference on Data Warehousing and Knowledge Discovery (DaWaK 2009), which was held from August 31 to S- tember 2, 2009 in Linz, Austria. Second, it contains a special section of papers on a particularly challenging domain in information retrieval, namely patent retrieval. Over the last decade, the International Conference on Data Warehousing and Knowledge Discovery (DaWaK) has established itself as one of the most important international scientific events within data warehousing and knowledge discovery. DaWaK brings together a wide range of researchers and practitioners working on these topics. The DaWaK conference series thus serves as a leading forum for discu- th ing novel research results and experiences within the field. The 11 International Conference on Data Warehousing and Knowledge Discovery (DaWaK 2009) cont- ued the tradition by disseminating and discussing innovative models, methods, al- rithms, and solutions to the challenges faced by data warehousing and knowledge discovery technologies.
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, the 33rd issue of Transactions on Large-Scale Data- and Knowledge-Centered Systems, contains five revised selected regular papers. Topics covered include distributed massive data streams, storage systems, scientific workflow scheduling, cost optimization of data flows, and fusion strategies.