Kaihe Xu


2024

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Reinforcement Learning with Token-level Feedback for Controllable Text Generation
Wendi Li | Wei Wei | Kaihe Xu | Wenfeng Xie | Dangyang Chen | Yu Cheng
Findings of the Association for Computational Linguistics: NAACL 2024

To meet the requirements of real-world applications, it is essential to control generations of large language models (LLMs). Prior research has tried to introduce reinforcement learning (RL) into controllable text generation while most existing methods suffer from overfitting issues (finetuning-based methods) or semantic collapse (post-processing methods). However, current RL methods are generally guided by coarse-grained (sentence/paragraph-level) feedback, which may lead to suboptimal performance owing to semantic twists or progressions within sentences. To tackle that, we propose a novel reinforcement learning algorithm named TOLE which formulates TOken-LEvel rewards for controllable text generation, and employs a “first-quantize-then-noise” paradigm to enhance the robustness of the RL algorithm. Furthermore, TOLE can be flexibly extended to multiple constraints with little computational expense. Experimental results show that our algorithm can achieve superior performance on both single-attribute and multi-attribute control tasks. We have released our codes at https://github.com/WindyLee0822/CTG.

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CNEQ: Incorporating numbers into Knowledge Graph Reasoning
Xianshu Peng | Wei Wei | Kaihe Xu | Dangyang Chen
Findings of the Association for Computational Linguistics: EMNLP 2024

Complex logical reasoning over knowledge graphs lies at the heart of many semantic downstream applications and thus has been extensively explored in recent years. However, nearly all of them overlook the rich semantics of numerical entities (e.g., magnitude, unit, and distribution) and are simply treated as common entities, or even directly removed. It may severely hinder the performance of answering queries involving numerical comparison or numerical computation. To address this issue, we propose the Complex Number and Entity Query model (CNEQ), which comprises a Number-Entity Predictor and an Entity Filter. The Number-Entity Predictor can independently learn the structural and semantic features of entities and numerical values, thereby enabling better prediction of entities as well as numerical values. The Entity Filter can compare or calculate numerical values to filter out entities that meet certain numerical constraints. To evaluate our model, we generated a variety of multi-hop complex logical queries including numerical values on three widely-used Knowledge Graphs: FB15K, DB15K, and YAGO15K. Experimental results demonstrate that CNEQ achieves state-of-the-art results.