This, the24th issue of Transactions on Large-Scale Data- and Knowledge-Centered Systems,contains extended and revised versions of seven papers presented at the 25thInternational Conference on Database and Expert Systems Applications, DEXA2014, held in Munich, Germany, in September 2014.

Reflective Constraint Writing.- PPP-Codes for Large-Scale Similarity Searching.- Solving Data Mismatches in Bioinformatics Workflows by Generating Data Converters.- A Framework for Sampling-Based XML Data Pricing.- kdANN+: A Rapid AkNN Classifier for Big Data.- Optimizing Inter-Data-Center Large-Scale Database Parallel Replication with Workload-Driven Partitioning.- Anonymization of Data Sets with NULL Values.

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 24th issue of Transactions on Large-Scale Data- and Knowledge-Centered Systems, contains extended and revised versions of seven papers presented at the 25th International Conference on Database and Expert Systems Applications, DEXA 2014, held in Munich, Germany, in September 2014. Following the conference, and two further rounds of reviewing and selection, six extended papers and one invited keynote paper were chosen for inclusion in this special issue. Topics covered include systems modeling, similarity search, bioinformatics, data pricing, k-nearest neighbor querying, database replication, and data anonymization.

Contains extended and improved versions of papers selected from DEXA 2014Includes an extensive keynote paper focusing on systems modelingCovers a wide range of topics on database- and expert-system applicationsIncludes supplementary material: sn.pub/extras