Lujun Li


2025

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Small Language Models in the Real World: Insights from Industrial Text Classification
Lujun Li | Lama Sleem | Niccolo’ Gentile | Geoffrey Nichil | Radu State
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 6: Industry Track)

With the emergence of ChatGPT, Transformer models have significantly advanced text classification and related tasks. Decoder-only models such as Llama exhibit strong performance and flexibility, yet they suffer from inefficiency on inference due to token-by-token generation, and their effectiveness in text classification tasks heavily depends on prompt quality. Moreover, their substantial GPU resource requirements often limit widespread adoption. Thus, the question of whether smaller language models are capable of effectively handling text classification tasks emerges as a topic of significant interest. However, the selection of appropriate models and methodologies remains largely underexplored. In this paper, we conduct a comprehensive evaluation of prompt engineering and supervised fine-tuning methods for transformer-based text classification. Specifically, we focus on practical industrial scenarios, including email classification, legal document categorization, and the classification of extremely long academic texts. We examine the strengths and limitations of smaller models, with particular attention to both their performance and their efficiency in Video Random-Access Memory (VRAM) utilization, thereby providing valuable insights for the local deployment and application of compact models in industrial settings.

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BayesKD: Bayesian Knowledge Distillation for Compact LLMs in Constrained Fine-tuning Scenarios
Wei Li | Lujun Li | Mark G. Lee | Shengjie Sun | Lei Zhang | Wei Xue | Yike Guo
Findings of the Association for Computational Linguistics: ACL 2025

Large language models (LLMs) have revolutionized various domains with their remarkable capabilities, but their massive parameter sizes pose significant challenges for fine-tuning and inference, especially in resource-constrained environments. Conventional compression methods often result in substantial performance degradation within LLMs and struggle to restore model quality during fine-tuning. To address this challenge, we present Bayesian Knowledge Distillation (BayesKD), a novel distillation framework meticulously designed for compact LLMs in resource-constrained fine-tuning scenarios. Departing from conventional LLM distillation methods that introduce time-consuming paradigms and fail to generalize in compressed LLM fine-tuning scenarios, our BayesKD develops the Logits Dual-Scaling, Knowledge Alignment Module, and Bayesian Distillation Optimization. In particular, our Logits Dual-Scaling strategy adaptively aligns the strength of the teacher’s knowledge transfer, while the Knowledge Alignment Module bridges the gap between the teacher and student models by projecting their knowledge representations into a shared interval. Additionally, we employ Logits-Aware Bayesian Optimization to swiftly identify optimal settings based on these strategies, thereby enhancing model performance. Extensive experiments across diverse tasks demonstrate that BayesKD consistently outperforms baseline methods on various state-of-the-art LLMs, including LLaMA, Qwen2, Bloom, and Vicuna. Notably, our BayesKD achieves average accuracy gains of 2.99% and 4.05% over standard KD for the 8B parameter LLaMA and Qwen2 model. Codes are available in the supplementary materials.

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How LLMs React to Industrial Spatio-Temporal Data? Assessing Hallucination with a Novel Traffic Incident Benchmark Dataset
Qiang Li | Mingkun Tan | Xun Zhao | Dan Zhang | Daoan Zhang | Shengzhao Lei | Anderson S. Chu | Lujun Li | Porawit Kamnoedboon
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 3: Industry Track)

Large language models (LLMs) hold revolutionary potential to digitize and enhance the Health & Public Services (H&PS) industry. Despite their advanced linguistic abilities, concerns about accuracy, stability, and traceability still persist, especially in high-stakes areas such as transportation systems. Moreover, the predominance of English in LLM development raises questions about how they perform in non-English contexts. This study originated from a real world industrial GenAI application, introduces a novel cross-lingual benchmark dataset comprising nearly 99,869 real traffic incident records from Vienna (2013-2023) to assess the robustness of state-of-the-art LLMs ( 9) in the spatio vs temporal domain for traffic incident classification. We then explored three hypotheses — sentence indexing, date-to-text conversion, and German-to-English translation — and incorporated Retrieval Augmented Generation (RAG) to further examine the LLM hallucinations in both spatial and temporal domain. Our experiments reveal significant performance disparities in the spatio-temporal domain and demonstrate what types of hallucinations that RAG can mitigate and how it achieves this. We also provide open access to our H&PS traffic incident dataset, with the project demo and code available at Website https://sites.google.com/view/llmhallucination/home

2024

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LPZero: Language Model Zero-cost Proxy Search from Zero
Peijie Dong | Lujun Li | Xiang Liu | Zhenheng Tang | Xuebo Liu | Qiang Wang | Xiaowen Chu
Findings of the Association for Computational Linguistics: EMNLP 2024

Despite the outstanding performance, Neural Architecture Search (NAS) is criticized for massive computation. Recently, Zero-shot NAS has emerged as a promising approach by exploiting Zero-cost (ZC) proxies, which markedly reduce computational demands. Despite this, existing ZC proxies heavily rely on expert knowledge and incur significant trial-and-error costs. Particularly in NLP tasks, most existing ZC proxies fail to surpass the performance of the naive baseline. To address these challenges, we introduce a novel framework, LPZero, which is the first to automatically design zero-cost (ZC) proxies for various tasks, achieving higher ranking consistency than human-designed proxies. Specifically, we model the ZC proxy as a symbolic equation and incorporate a unified proxy search space that encompasses existing ZC proxies, which are composed of a predefined set of mathematical symbols. To heuristically search for the best ZC proxy, LPZero incorporates genetic programming to find the optimal symbolic composition. We propose a Predictive-Pruning Strategy (PPS), which preemptively eliminates unpromising proxies, thereby mitigating the risk of proxy degradation. Extensive experiments on FlexiBERT, GPT-2, and LLaMA-7B demonstrate LPZero’s superior ranking ability and performance on downstream tasks compared to current approaches.