H-Mem: Hybrid Multi-Dimensional Memory Management for Long-Context Conversational Agents

Zihe Ye, Jingyuan Huang, Weixin Chen, Yongfeng Zhang


Abstract
Long-context conversational agents require robust memory, but existing frameworks struggle to organize information effectively across dimensions like time and topic, leading to poor retrieval. To address this, we introduce H-Mem, a novel Hybrid Multi-Dimensional Memory architecture. H-Mem stores conversational facts in two parallel, hierarchical data structures: a temporal tree that organizes information chronologically and a semantic tree that organizes it conceptually. This dual-tree design enables a hybrid retrieval mechanism managed by an intelligent Mode Controller. Based on the query, the controller dynamically chooses between a sequential search using semantic anchors and an intersective search combining both hierarchies. Our experiments on long-context QA datasets demonstrate that H-Mem provides a more flexible approach to memory management, leading to significant improvements of over 8.4% compared to other state-of-the-art systems.
Anthology ID:
2026.eacl-long.363
Volume:
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
EACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
7756–7775
Language:
URL:
https://preview.aclanthology.org/ingest-eacl/2026.eacl-long.363/
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Bibkey:
Cite (ACL):
Zihe Ye, Jingyuan Huang, Weixin Chen, and Yongfeng Zhang. 2026. H-Mem: Hybrid Multi-Dimensional Memory Management for Long-Context Conversational Agents. In Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 7756–7775, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
H-Mem: Hybrid Multi-Dimensional Memory Management for Long-Context Conversational Agents (Ye et al., EACL 2026)
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https://preview.aclanthology.org/ingest-eacl/2026.eacl-long.363.pdf