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.
the 42nd issue of Transactions on Large-Scale Data- and Knowledge-Centered Systems, consists of five revised selected regular
papers, presenting the following topics: Privacy-Preserving Top-k Query Processing in Distributed Systems; Trust Factors and
Insider Threats in Permissioned Distributed Ledgers: An Analytical Study and Evaluation of Popular DLT Frameworks; Polystore
and Tensor Data Model for Logical Data Independence and Impedance Mismatch in Big Data Analytics; A General Framework for
Multiple Choice Question Answering Based on Mutual Information and Reinforced Co-occurrence; Rejig: A Scalable Online Algorithm
for Cache Server Configuration Changes.