Zongfang Liu
Author directory2026
How to Score Experts for One-Shot MoE Expert Pruning: A Systematic Formulation and Selection Principle
Zongfang Liu | Jinghui Zhang | Zijian Ma | Guangyi Chen | Xin Yuan
Findings of the Association for Computational Linguistics: EMNLP 2026
Zongfang Liu | Jinghui Zhang | Zijian Ma | Guangyi Chen | Xin Yuan
Findings of the Association for Computational Linguistics: EMNLP 2026
Mixture-of-Experts (MoE) language models reduce per-token computation through sparse expert activation, yet deployment still requires storing the full expert pool, making one-shot expert pruning a practical approach for reducing memory usage. Although effective, existing criteria are largely heuristic, and no single criterion is universally optimal. Thus, establishing a principle for selecting pruning criteria suited to different deployment objectives remains an important yet largely underexplored problem in one-shot expert pruning. To this end, we introduce a systematic formulation for one-shot MoE expert pruning organized around three factors: routing frequency, gate weighting, and activation strength. The formulation yields a criteria selection principle: task-agnostic pruning should favor routed-token-averaged, gate-free activation-based criteria, whereas task-specific pruning can benefit from retaining routing-frequency and gate-weight information. Beyond this principle, the formulation also provides a systematic view of existing heuristic criteria and gives rise to two new task-agnostic criteria, Mean Activation Norm (MAN) and Mean Squared Activation Norm (MSAN). Across four representative MoE models and 16 diverse benchmarks, MAN and MSAN are consistently strong in the task-agnostic setting, obtain the top-two average ranks, and improve average performance by 4.0 points on average and up to 8.8 points over the strongest baseline.
AIMER: Calibration-Free Task-Agnostic MoE Expert Pruning
Zongfang Liu | Guangyi Chen | Yifan Shen | Shengkun Tang | Huan Wang | Xin Yuan
Findings of the Association for Computational Linguistics: EMNLP 2026
Zongfang Liu | Guangyi Chen | Yifan Shen | Shengkun Tang | Huan Wang | Xin Yuan
Findings of the Association for Computational Linguistics: EMNLP 2026
Mixture-of-Experts (MoE) language models increase parameter capacity without proportional per-token computation, yet deployment still requires storing the full expert pool, making expert pruning important for reducing memory and serving overhead. Existing task-agnostic expert-pruning methods are typically calibration-dependent: they estimate expert importance from routing or activation statistics on a calibration set, making pruning decisions sensitive to calibration-data variation while introducing substantial preprocessing cost. We propose AIMER (Absolute mean over root mean square IMportance for Expert Ranking), a simple calibration-free criterion that identifies more distinct experts by capturing the concentration pattern of expert weights, making it well suited for task-agnostic expert pruning. Across 7B to 47B MoE language models with distinct architectures and 16 diverse benchmarks, AIMER consistently delivers stronger capability balance across diverse tasks than existing calibration-free methods. Surprisingly, AIMER also achieves better balance than strong calibration-based expert-pruning baselines calibrated on the widely used task-agnostic C4 corpus, while requiring only 0.22–2.06 seconds to score all experts.
2025
Decoding Echo Chambers: LLM-Powered Simulations Revealing Polarization in Social Networks
Chenxi Wang | Zongfang Liu | Dequan Yang | Xiuying Chen
Proceedings of the 31st International Conference on Computational Linguistics
Chenxi Wang | Zongfang Liu | Dequan Yang | Xiuying Chen
Proceedings of the 31st International Conference on Computational Linguistics
The impact of social media on critical issues such as echo chambers, needs to be addressed, as these phenomena can have disruptive consequences for our society. Traditional research often oversimplifies emotional tendencies and opinion evolution into numbers and formulas, neglecting that news and communication are conveyed through text, which limits these approaches. Hence, in this work, we propose an LLM-based simulation for the social opinion network to evaluate and counter polarization phenomena. We first construct three typical network structures to simulate different characteristics of social interactions. Then, agents interact based on recommendation algorithms and update their strategies through reasoning and analysis. By comparing these interactions with the classic Bounded Confidence Model (BCM), the Friedkin-Johnsen (FJ) model, and using echo chamber-related indices, we demonstrate the effectiveness of our framework in simulating opinion dynamics and reproducing phenomena such as opinion polarization and echo chambers. We propose two mitigation methods—active and passive nudges—that can help reduce echo chambers, specifically within language-based simulations. We hope our work will offer valuable insights and guidance for social polarization mitigation.