A Secure and Interoperable Big Data Platform for AI-Driven Healthcare Solutions: Insights From the GATEKEEPER Project - Christian Temporale; E. De Salvo; Eugenio Gaeta; Miguel Rujas; Laura Lopez-Perez; Muhammad Salman Haleem; Vasilis Aidonis; Eleni I. Georga; Dimitrios Fotiadis; Leandro Pecchia; Giuseppe Fico (IEEE ACCESS, 2026)