The LNCS journal Transactions on Large-scale Data and Knowledge-centered Systemsfocuses on data management, knowledge discovery, and knowledge processing, which arecore and hot topics in computer science. Since the 1990s, the Internet has become the maindriving force behind application development in all domains. An increase in the demand forresource sharing (e.g. computing resources, services, metadata, data sources) across differentsites connected through networks has led to an evolution of data- and knowledge-managementsystems from centralized systems to decentralized systems enabling large-scale distributedapplications providing high scalability.This, the 57th issue of Transactions on Large-scale Data and Knowledge-centered Systems, contains five fully revised selected regular papers. Topics covered include leveraging machinelearning for effective data management, access control models, reciprocal authorizations, Internet of Things, digital forensics, code similarity search, volunteered geographicinformation, and spatial data quality.