Lijun Zhang

Dr. Lijun Zhang


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

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

Representative Publications

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28 June 2024 in Applied Sciences
Verified
Journal Article
Open access
PDF file
HZHanwei Zhang
Hanwei Zhang
YZYing Zhu
Ying Zhu
DWDan Wang
Dan Wang
LZLijun Zhang
Lijun Zhang
TCTianxiang Chen
Tianxiang Chen
ZYZi Ye
Zi Ye
State space models (SSM) with selection mechanisms and hardware-aware architectures, namely Mamba, have recently shown significant potential in long-sequence modeling. Since the complexity of transformers’ self-attention mechanism is quadratic with image size, as well as increasing computational demands, researchers are currently exploring how to adapt Mamba for computer vision tasks. This paper is the first comprehensive survey that aims to provide an in-depth analysis of Mamba models within the domain of computer vision. It begins by exploring the foundational concepts contributing to Mamba’s success, including the SSM framework, selection mechanisms, and hardware-aware design. Then, we review these vision Mamba models by categorizing them into foundational models and those enhanced with techniques including convolution, recurrence, and attention to improve their sophistication. Furthermore, we investigate the widespread applications of Mamba in vision tasks, which include their use as a backbone in various levels of vision processing. This encompasses general visual tasks, medical visual tasks (e.g., 2D/3D segmentation, classification, image registration, etc.), and remote sensing visual tasks. In particular, we introduce general visual tasks from two levels: high/mid-level vision (e.g., object detection, segmentation, video classification, etc.) and low-level vision (e.g., image super-resolution, image restoration, visual generation, etc.). We hope this endeavor will spark additional interest within the community to address current challenges and further apply Mamba models in computer vision.

26 December 2024 in Formal Aspects of Computing
Verified
Journal Article
Open access
MBMaurice H. ter Beek
Maurice H. ter Beek
RCRod Chapman
Rod Chapman
RCRance Cleaveland
Rance Cleaveland
HGHubert Garavel
Hubert Garavel
RGRong Gu
Rong Gu
LZLijun Zhang
Lijun Zhang
Formal methods encompass a wide choice of techniques and tools for the specification, development, analysis, and verification of software and hardware systems. Formal methods are widely applied in industry, in activities ranging from the elicitation of requirements and the early design phases all the way to the deployment, configuration, and runtime monitoring of actual systems. Formal methods allow one to precisely specify the environment in which a system operates, the requirements and properties that the system should satisfy, the models of the system used during the various design steps, and the code embedded in the final implementation, as well as to express conformance relations between these specifications. We present a broad scope of successful applications of formal methods in industry, not limited to the well-known success stories from the safety-critical domain, like railways and other transportation systems, but also covering other areas such as lithography manufacturing and cloud security in e-commerce, to name but a few. We also report testimonies from a number of representatives from industry who, either directly or indirectly, use or have used formal methods in their industrial project endeavours. These persons are spread geographically, including Europe, Asia, North and South America, and the involved projects witness the large coverage of applications of formal methods, not limited to the safety-critical domain. We thus make a case for the importance of formal methods, and in particular of the capacity to abstract and mathematical reasoning that are taught as part of any formal methods course. These are fundamental Computer Science skills that graduates should profit from when working as computer scientists in industry, as confirmed by industry representatives.

1 September 2025 in Scientific Reports
Verified
Journal Article
Open access
PDF file
ZYZi Ye
Zi Ye
TCTianxiang Chen
Tianxiang Chen
FWFangyijie Wang
Fangyijie Wang
HZHanwei Zhang
Hanwei Zhang
LZLijun Zhang
Lijun Zhang
Segmenting echocardiographic images is a crucial step in assessing heart function, as clinical indicators can be obtained by precisely delineating the left ventricle. The success of subsequent heart analyses depends entirely on the precision of this segmentation. However, echocardiography is characterized by ambiguity and heavy background noise interference, making accurate segmentation more challenging. Present methods lack efficiency and are prone to mistakenly segmenting some background noise areas, such as the left ventricular area, due to noise disturbance. To address these issues, we introduce P-Mamba, which integrates the Mixture of Experts (MoE) concept for efficient pediatric echocardiographic left ventricular segmentation. Specifically, we utilize the recently proposed ViM layers from the vision mamba to enhance our model’s computational and memory efficiency while modeling global dependencies. In the DWT-based (Discrete Wavelet Transform) Perona-Malik Diffusion (PMD) Block, we introduce a block that suppresses noise while preserving the left ventricle’s local shape cues. Consequently, our proposed P-Mamba innovatively combines the PMD’s noise suppression and local feature extraction capabilities with Mamba’s efficient design for global dependency modeling. We conducted segmentation experiments on two pediatric ultrasound datasets and a general ultrasound dataset, namely Echonet-dynamic, and achieved state-of-the-art (SOTA) results. Specifically, on the Pediatric PSAX (8959 images) and Pediatric A4C datasets (6425 images), we achieved Dice scores of 0.922 and 0.906, respectively; on the EchoNet-Dynamic dataset (19882 images), we achieved a Dice score of 0.931. Leveraging the strengths of the P-Mamba block, our model demonstrates superior accuracy and efficiency compared to established models, including vision transformers with quadratic and linear computational complexity.

20 March 2021
Verified
Book Chapter
Open access
PDF file
PYPengfei Yang
Pengfei Yang
RLRenjue Li
Renjue Li
JLJianlin Li
Jianlin Li
CHCheng-Chao Huang
Cheng-Chao Huang
JWJingyi Wang
Jingyi Wang
LZLijun Zhang
Lijun Zhang
We propose a spurious region guided refinement approach for robustness verification of deep neural networks. Our method starts with applying the DeepPoly abstract domain to analyze the network. If the robustness property cannot be verified, the result is inconclusive. Due to the over-approximation, the computed region in the abstraction may be spurious in the sense that it does not contain any true counterexample. Our goal is to identify such spurious regions and use them to guide the abstraction refinement. The core idea is to make use of the obtained constraints of the abstraction to infer new bounds for the neurons. This is achieved by linear programming techniques. With the new bounds, we iteratively apply DeepPoly, aiming to eliminate spurious regions. We have implemented our approach in a prototypical tool DeepSRGR. Experimental results show that a large amount of regions can be identified as spurious, and as a result, the precision of DeepPoly can be significantly improved. As a side contribution, we show that our approach can be applied to verify quantitative robustness properties.

1 September 2011
Verified
Conference Paper
Open access
EHErnst Moritz Hahn
Ernst Moritz Hahn
Gethin NormanGethin Norman
Gethin Norman
DPDavid Parker
David Parker
BWBjorn Wachter
Bjorn Wachter
LZLijun Zhang
Lijun Zhang
We consider a class of hybrid systems that involve random phenomena, in addition to discrete and continuous behaviour. Examples of such systems include wireless sensing and control applications. We propose and compare two abstraction techniques for this class of models, which yield lower and upper bounds on the optimal probability of reaching a particular class of states. We also demonstrate the applicability of these abstraction techniques to the computation of long-run average reward properties and the synthesis of controllers. The first of the two abstractions yields more precise information, while the second is easier to construct. For the latter, we demonstrate how existing solvers for hybrid systems can be leveraged to perform the computation.

1 June 2021 in Formal Aspects of Computing
Verified
Journal Article
Open access
PYPengfei Yang
Pengfei Yang
JLJianlin Li
Jianlin Li
JLJiangchao Liu
Jiangchao Liu
CHCheng-Chao Huang
Cheng-Chao Huang
RLRenjue Li
Renjue Li
LZLijun Zhang
Lijun Zhang
Deep neural networks (DNNs) have been shown lack of robustness, as they are vulnerable to small perturbations on the inputs. This has led to safety concerns on applying DNNs to safety-critical domains. Several verification approaches based on constraint solving have been developed to automatically prove or disprove safety properties for DNNs. However, these approaches suffer from the scalability problem, i.e., only small DNNs can be handled. To deal with this, abstraction based approaches have been proposed, but are unfortunately facing the precision problem, i.e., the obtained bounds are often loose. In this paper, we focus on a variety of local robustness properties and a (δ,ε) -global robustness property of DNNs, and investigate novel strategies to combine the constraint solving and abstraction-based approaches to work with these properties: We propose a method to verify local robustness, which improves a recent proposal of analyzing DNNs through the classic abstract interpretation technique, by a novel symbolic propagation technique. Specifically, the values of neurons are representedsymbolicallyand propagated from the input layer to the output layer, on top of the underlying abstract domains. It achieves significantly higher precision and thus can prove more properties. We propose a Lipschitz constant based verification framework. By utilising Lipschitz constants solved by semidefinite programming, we can prove global robustness of DNNs. We show how the Lipschitz constant can be tightened if it is restricted to small regions. A tightened Lipschitz constantcan be helpful in proving local robustness properties. Furthermore, a global Lipschitz constant can be used to accelerate batch local robustness verification, and thus support the verification of global robustness. We show how the proposed abstract interpretation and Lipschitz constant based approaches can benefit from each other to obtain more precise results. Moreover, they can be also exploited and combined to improve constraints based approach. We implement our methods in the tool PRODeep, and conduct detailed experimental results on several benchmarks