Chengming Xu

Chengming Xu


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 June 2024 in Proceedings of the ACM on Programming Languages
Verified
Journal Article
Open access
DBDebangshu Banerjee
Debangshu Banerjee
CXChengming Xu
Chengming Xu
GSGagandeep Singh
Gagandeep Singh
We consider the verification of input-relational properties defined over deep neural networks (DNNs) such as robustness against universal adversarial perturbations, monotonicity, etc. Precise verification of these properties requires reasoning about multiple executions of the same DNN. We introduce a novel concept of difference tracking to compute the difference between the outputs of two executions of the same DNN at all layers. We design a new abstract domain, DiffPoly for efficient difference tracking that can scale large DNNs. DiffPoly is equipped with custom abstract transformers for common activation functions (ReLU, Tanh, Sigmoid, etc.) and affine layers and can create precise linear cross-execution constraints. We implement an input-relational verifier for DNNs called RaVeN which uses DiffPoly and linear program formulations to handle a wide range of input-relational properties. Our experimental results on challenging benchmarks show that by leveraging precise linear constraints defined over multiple executions of the DNN, RaVeN gains substantial precision over baselines on a wide range of datasets, networks, and input-relational properties.

30 June 2025 in Foundations and Trends® in Programming Languages
Verified
Journal Article
Open access
PDF file
GSGagandeep Singh
Gagandeep Singh
JLJacob Laurel
Jacob Laurel
SMSasa Misailovic
Sasa Misailovic
DBDebangshu Banerjee
Debangshu Banerjee
ASAvaljot Singh
Avaljot Singh
HZHuan Zhang
Huan Zhang
Deep neural networks (DNNs) now dominate the AI landscape and have shown impressive performance in diverse application domains, including vision, natural language processing (NLP), and healthcare. However, both public and private entities have been increasingly expressing significant concern about the potential of state-of-the-art AI models to cause societal and financial harm. This lack of trust arises from their black-box construction and vulnerability against natural and adversarial noise. As a result, researchers have spent considerable time developing automated methods for building safe and trustworthy DNNs. Abstract interpretation has emerged as the most popular framework for efficiently analyzing realistic DNNs among the various approaches. However, due to fundamental differences in the computational structure (e.g., high nonlinearity) of DNNs compared to traditional programs, developing efficient DNN analyzers has required tackling significantly different research challenges than encountered for programs. In this monograph, we describe state-of-the-art approaches based on abstract interpretation for analyzing DNNs. These approaches include the design of new abstract domains, synthesis of novel abstract transformers, abstraction refinement, and incremental analysis. We will discuss how the analysis results can be used to: (i) formally check whether a trained DNN satisfies desired output and gradient-based safety properties, (ii) guide the model updates during training towards satisfying safety properties, and (iii) reliably explain and interpret the black-box workings of DNNs.

21 November 2024
Verified
Book Chapter
Closed access
PDF file
CXChengming Xu
Chengming Xu
GSGagandeep Singh
Gagandeep Singh

6 January 2023 in arXiv
Verified
Preprint
Open access
PDF file
CXChengming Xu
Chengming Xu
SYSiqian Yang
Siqian Yang
YWYabiao Wang
Yabiao Wang
ZWZhanxiong Wang
Zhanxiong Wang
Yanwei FuYanwei Fu
Yanwei Fu
XXXiangyang Xue
Xiangyang Xue
The task of Few-shot Learning (FSL) aims to do the inference on novel categories containing only few labeled examples, with the help of knowledge learned from base categories containing abundant labeled training samples. While there are numerous works into FSL task, Vision Transformers (ViTs) have rarely been taken as the backbone to FSL with few trials focusing on naive finetuning of whole backbone or classification layer.} Essentially, despite ViTs have been shown to enjoy comparable or even better performance on other vision tasks, it is still very nontrivial to efficiently finetune the ViTs in real-world FSL scenarios. To this end, we propose a novel efficient Transformer Tuning (eTT) method that facilitates finetuning ViTs in the FSL tasks. The key novelties come from the newly presented Attentive Prefix Tuning (APT) and Domain Residual Adapter (DRA) for the task and backbone tuning, individually. Specifically, in APT, the prefix is projected to new key and value pairs that are attached to each self-attention layer to provide the model with task-specific information. Moreover, we design the DRA in the form of learnable offset vectors to handle the potential domain gaps between base and novel data. To ensure the APT would not deviate from the initial task-specific information much, we further propose a novel prototypical regularization, which maximizes the similarity between the projected distribution of prefix and initial prototypes, regularizing the update procedure. Our method receives outstanding performance on the challenging Meta-Dataset. We conduct extensive experiments to show the efficacy of our model.

13 June 2025 in arXiv
Verified
Preprint
Open access
PDF file
CXChengming Xu
Chengming Xu
GSGagandeep Singh
Gagandeep Singh
Deep neural networks deployed in safety-critical, resource-constrained environments must balance efficiency and robustness. Existing methods treat compression and certified robustness as separate goals, compromising either efficiency or safety. We propose CACTUS (Compression Aware Certified Training Using network Sets), a general framework for unifying these objectives during training. CACTUS models maintain high certified accuracy even when compressed. We apply CACTUS for both pruning and quantization and show that it effectively trains models which can be efficiently compressed while maintaining high accuracy and certifiable robustness. CACTUS achieves state-of-the-art accuracy and certified performance for both pruning and quantization on a variety of datasets and input specifications.

25 October 2026 in Electronics
Verified
Journal Article
Open access
PDF file
QMQingxia Meng
Qingxia Meng
CXChengming Xu
Chengming Xu
ZLZhirui Liu
Zhirui Liu
SYSheng-Zhi Yang
Sheng-Zhi Yang
QYQian Yu
Qian Yu
Wenqi RenWenqi Ren
Wenqi Ren
The development of diffusion models (DMs) has greatly enhanced text-to-image generation, outperforming previous methods like generative adversarial networks (GANs) in terms of image quality and text alignment. However, accurately generating human body images remains challenging, often resulting in disproportionate figures and anatomical errors, which limits their practical applications in areas such as portrait generation. While previous methods such as HcP have shown promising results, limitations, including the retention of noisy priors, limited understanding of human representation, and restriction of generalization power, still exist due to the specific design of fully supervised learning with only pose-related information. In this study, we introduce a novel method to enhance pretrained diffusion models for realistic human body generation by incorporating dual-level human prior knowledge. Our approach involves learning shape-level details with the human-related tokens in the original prompts, and learning pose-level priors by adding a learnable pose-aware token to each text prompt. We use a two-stage training strategy to rectify the cross-attentions with a bind-then-generalize process, leveraging multiple novel objectives along with adversarial training. Paired comparisons on SD1.5 and SDXL, under identical prompts and generation seeds, show more coherent human bodies than the pretrained models and a LoRA baseline trained on the same images. Image-level metrics improve on SDXL. Those metrics measure image quality, distributional similarity, and preference. The anatomical comparison is carried by the paired images and the attention maps.