Heterogeneous Knowledge Fusion: A Novel Approach for Personalized Recommendation via LLM

In the context of Meituan Waimai, user behavior exhibits heterogeneous characteristics, including various behavior subjects, content, scenarios. The current industry approach mostly involves continuously adding various heterogeneous behavior to the traditional recommendation models, which brings two obvious problems. Firstly, the multitude of behavior subjects leads to sparse features that pose challenges to efficient modeling. Secondly, separating the modeling of user, merchant, and commodity behavior ignores the fusion of heterogeneous knowledge among behavior. However, we have noticed that heterogeneous user behavior contain rich semantic knowledge, and using semantics to represent and reason about user behavior can more effectively promote heterogeneous knowledge fusion and capture user interests. LLMs have shown remarkable capabilities in various fields, thanks to rich semantic knowledge and powerful inferential reasoning [1, 10]. We have designed a new user behavior modeling framework via LLM, which extracts and integrates heterogeneous knowledge from heterogeneous behavior information of users, and transforms structured user behavior into unstructured heterogeneous knowledge. In the field of recommendation, there have been some attempts to use LLM for personalized recommendation.