Jianshu Zhang


2025

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VLM2-Bench: A Closer Look at How Well VLMs Implicitly Link Explicit Matching Visual Cues
Jianshu Zhang | Dongyu Yao | Renjie Pi | Paul Pu Liang | Yi R. Fung
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Visually linking matching cues is a crucial ability in daily life, such as identifying the same person in multiple photos based on their cues, even without knowing who they are. Despite the extensive knowledge that vision-language models (VLMs) possess, it remains largely unexplored whether they are capable of performing this fundamental task. To address this, we introduce VLM2-Bench, a benchmark designed to assess whether VLMs can Visually Link Matching cues, with 9 subtasks and over 3,000 test cases. Comprehensive evaluation across twelve VLMs, along with further analysis of various language-side and vision-side prompting methods, leads to a total of eight key findings. We identify critical challenges in models’ ability to link visual cues, highlighting a significant performance gap. Based on these insights, we advocate for (i) enhancing core visual capabilities to improve adaptability and reduce reliance on prior knowledge, (ii) establishing clearer principles for integrating language-based reasoning in vision-centric tasks to prevent unnecessary biases, and (iii) shifting vision-text training paradigms toward fostering models’ ability to independently structure and infer relationships among visual cues.

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Bridge-Coder: Transferring Model Capabilities from High-Resource to Low-Resource Programming Language
Jipeng Zhang | Jianshu Zhang | Yuanzhe Li | Renjie Pi | Rui Pan | Runtao Liu | Zheng Ziqiang | Tong Zhang
Findings of the Association for Computational Linguistics: ACL 2025

Most LLMs universally excel at generating code for high-resource programming languages (HRPLs) like Python, a capability that has become standard due to the abundance of training data. However, they struggle significantly with low-resource programming languages (LRPLs) such as D, exacerbating the digital divide. This gap limits developers using LRPLs from equally benefiting and hinders innovation within underrepresented programming communities. To make matters worse, manually generating data for LRPLs is highly labor intensive and requires expensive expert effort. In this work, we begin by analyzing the NL-PL Gap, where LLMs’ direct-generated LRPL data often suffers from subpar quality due to the misalignment between natural language (NL) instructions and programming language (PL) outputs. To address this issue, we introduce Bridge-Assist Generation, a method to generate LRPL data utilizing LLM’s general knowledge, HRPL proficiency, and in-context learning capabilities. To further maximize the utility of the generated data, we propose Bridged Alignment to obtain Bridge-Coder. To thoroughly evaluate our approach, we select four relatively LRPLs: R, D, Racket, and Bash. Experimental results reveal that Bridge-Coder achieves significant improvements over the original model, with average gains of 18.71 and 10.81 on two comprehensive benchmarks, M-HumanEval and M-MBPP.

2024

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FIRST: Teach A Reliable Large Language Model Through Efficient Trustworthy Distillation
KaShun Shum | Minrui Xu | Jianshu Zhang | Zixin Chen | Shizhe Diao | Hanze Dong | Jipeng Zhang | Muhammad Omer Raza
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing

Large language models (LLMs) have become increasingly prevalent in our daily lives, leading to an expectation for LLMs to be trustworthy —- both accurate and well-calibrated (the prediction confidence should align with its ground truth correctness likelihood). Nowadays, fine-tuning has become the most popular method for adapting a model to practical usage by significantly increasing accuracy on downstream tasks. Despite the great accuracy it achieves, we found fine-tuning is still far away from satisfactory trustworthiness due to “tuning-induced mis-calibration”. In this paper, we delve deeply into why and how mis-calibration exists in fine-tuned models, and how distillation can alleviate the issue. Then we further propose a brand new method named Efficient Trustworthy Distillation (FIRST), which utilizes a small portion of teacher’s knowledge to obtain a reliable language model in a cost-efficient way. Specifically, we identify the “concentrated knowledge” phenomenon during distillation, which can significantly reduce the computational burden. Then we apply a “trustworthy maximization” process to optimize the utilization of this small portion of concentrated knowledge before transferring it to the student. Experimental results demonstrate the effectiveness of our method, where better accuracy (+2.3%) and less mis-calibration (-10%) are achieved on average across both in-domain and out-of-domain scenarios, indicating better trustworthiness.

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MLLM-Protector: Ensuring MLLM’s Safety without Hurting Performance
Renjie Pi | Tianyang Han | Jianshu Zhang | Yueqi Xie | Rui Pan | Qing Lian | Hanze Dong | Jipeng Zhang | Tong Zhang
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing

The deployment of multimodal large language models (MLLMs) has brought forth a unique vulnerability: susceptibility to malicious attacks through visual inputs. This paper investigates the novel challenge of defending MLLMs against such attacks. Compared to large language models (LLMs), MLLMs include an additional image modality. We discover that images act as a “foreign language” that is not considered during safety alignment, making MLLMs more prone to producing harmful responses. Unfortunately, unlike the discrete tokens considered in text-based LLMs, the continuous nature of image signals presents significant alignment challenges, which poses difficulty to thoroughly cover all possible scenarios. This vulnerability is exacerbated by the fact that most state-of-the-art MLLMs are fine-tuned on limited image-text pairs that are much fewer than the extensive text-based pretraining corpus, which makes the MLLMs more prone to catastrophic forgetting of their original abilities during safety fine-tuning. To tackle these challenges, we introduce MLLM-Protector, a plug-and-play strategy that solves two subtasks: 1) identifying harmful responses via a lightweight harm detector, and 2) transforming harmful responses into harmless ones via a detoxifier. This approach effectively mitigates the risks posed by malicious visual inputs without compromising the original performance of MLLMs. Our results demonstrate that MLLM-Protector offers a robust solution to a previously unaddressed aspect of MLLM security.

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UniTabNet: Bridging Vision and Language Models for Enhanced Table Structure Recognition
Zhenrong Zhang | Shuhang Liu | Pengfei Hu | Jiefeng Ma | Jun Du | Jianshu Zhang | Yu Hu
Findings of the Association for Computational Linguistics: EMNLP 2024

In the digital era, table structure recognition technology is a critical tool for processing and analyzing large volumes of tabular data. Previous methods primarily focus on visual aspects of table structure recovery but often fail to effectively comprehend the textual semantics within tables, particularly for descriptive textual cells. In this paper, we introduce UniTabNet, a novel framework for table structure parsing based on the image-to-text model. UniTabNet employs a “divide-and-conquer” strategy, utilizing an image-to-text model to decouple table cells and integrating both physical and logical decoders to reconstruct the complete table structure. We further enhance our framework with the Vision Guider, which directs the model’s focus towards pertinent areas, thereby boosting prediction accuracy. Additionally, we introduce the Language Guider to refine the model’s capability to understand textual semantics in table images. Evaluated on prominent table structure datasets such as PubTabNet, PubTables1M, WTW, and iFLYTAB, UniTabNet achieves a new state-of-the-art performance, demonstrating the efficacy of our approach. The code will also be made publicly available.