Zhixuan Liu
2024
Inference-Time Language Model Alignment via Integrated Value Guidance
Zhixuan Liu
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Zhanhui Zhou
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Yuanfu Wang
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Chao Yang
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Yu Qiao
Findings of the Association for Computational Linguistics: EMNLP 2024
Large language models are typically fine-tuned to align with human preferences, but tuning large models is computationally intensive and complex. In this work, we introduce **Integrated Value Guidance (IVG)**, a method that uses implicit and explicit value functions to guide language model decoding at token and chunk-level respectively, efficiently aligning large language models purely at inference time.This approach circumvents the complexities of direct fine-tuning and outperforms traditional methods.Empirically, we demonstrate the versatility of IVG across various tasks. In controlled sentiment generation and summarization tasks, our method significantly improves the alignment of large models using inference-time guidance from **gpt2**-based value functions. Moreover, in a more challenging instruction-following benchmark AlpacaEval 2.0, we show that both specifically tuned and off-the-shelf value functions greatly improve the length-controlled win rates of large models against gpt-4-turbo (e.g., 19.51 % → 26.51% for **Mistral-7B-Instruct-v0.2** and 25.58 % → 33.75 % for **Mixtral-8x7B-Instruct-v0.1** with Tulu guidance).
2022
A Neural-Symbolic Approach to Natural Language Understanding
Zhixuan Liu
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Zihao Wang
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Yuan Lin
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Hang Li
Findings of the Association for Computational Linguistics: EMNLP 2022
Deep neural networks, empowered by pre-trained language models, have achieved remarkable results in natural language understanding (NLU) tasks. However, their performances can drastically deteriorate when logical reasoning is needed. This is because NLU in principle depends on not only analogical reasoning, which deep neural networks are good at, but also logical reasoning. According to the dual-process theory, analogical reasoning and logical reasoning are respectively carried out by System 1 and System 2 in the human brain. Inspired by the theory, we present a novel framework for NLU called Neural-Symbolic Processor (NSP), which performs analogical reasoning based on neural processing and logical reasoning based on both neural and symbolic processing. As a case study, we conduct experiments on two NLU tasks, question answering (QA) and natural language inference (NLI), when numerical reasoning (a type of logical reasoning) is necessary. The experimental results show that our method significantly outperforms state-of-the-art methods in both tasks.
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Co-authors
- Zhanhui Zhou 1
- Yuanfu Wang 1
- Chao Yang 1
- Yu Qiao 1
- Zihao Wang 1
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