Shuqi Cao Jingyi He Fei Tan HiGMem: A Hierarchical and LLM-Guided Memory System for Long-Term Conversational Agents. 33853-33862 2026 ACL (Findings) https://doi.org/10.18653/v1/2026.findings-acl.1690 https://aclanthology.org/2026.findings-acl.1690/ conf/acl/2026f db/conf/acl/acl2026f.html#CaoHT26