Optimizing Secure Multi-User ISAC Systems With STAR-RIS: A Deep Reinforcement Learning Approach for 6G Networks. - Mian Muhammad Kamal; Syed Zain Ul Abideen; Mahmoud Ahmad Al-Khasawneh; Amerah A. Alabrah; Raja Sohail Ahmed Larik; Muhammad Irfan Marwat (IEEE Access, 2025)