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SHARP POINTWISE-IN-TIME ERROR ESTIMATE OF L1 SCHEME FOR NONLINEAR SUBDIFFUSION EQUATIONS

Journal of Computational Mathematics 2024年第3期42卷 662-678页

作者： Dongfang Li Hongyu Qin Jiwei Zhang School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and TechnologyWuhan 430074China School of Mathematics and Statistics Wuhan UniversityWuhan 430072China

An essential feature of the subdiffusion equations with theα-order time fractional derivative is the weak singularity at the initial *** weak regularity of the solution is usually characterized by a regularity parameterσ∈(0,1)∪(1,2).Under this general regularity assumption,we present a rigorous analysis for the truncation errors and develop a new tool to obtain the stability results,i.e.,a refined discrete fractional-type Grönwall inequality(DFGI).After that,we obtain the pointwise-in-time error estimate of the widely used L1 scheme for nonlinear subdiffusion *** present results fill the gap on some interesting convergence results of L1 scheme onσ∈(0,α)∪(α,1)∪(1,2].Numerical experiments are provided to demonstrate the effectiveness of our theoretical analysis.

关键词： Sharp pointwise-in-time error estimate Ll scheme Nonlinear subdiffusion equations Non-smooth solutions

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Differentiating Malicious and Benign Android App Operations Using Second-Step Behavior Features

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Chinese Journal of Electronics 2019年第5期28卷 944-952页

作者： LI Pengwei FU Jianming XU Chao CHENG Binlin ZHANG Huanguo School of Information Engineering Nanjing Audit University School of Cyber Science and Engineering Wuhan University Key Laboratory of Aerospace Information Security and Trusted Computing Ministry of Education Wuhan University College of Computer Science and Technology Hubei Normal University

Security-sensitive operations in Android applications(apps for short) can either be benign or malicious. In this work, we introduce an approach of static program analysis that extracts "second-step behavior features", i.e., what was triggered by the security-sensitive operation, to assist app analysis in differentiating between malicious and benign operations. Firstly, we summarized the characteristics of malicious operations, such as spontaneity, independence, stealthiness and continuity,which can be used to classify the malicious operations and benign ones. Secondly, according to these characteristics,Second step behavior features(SSBFs for short) have been presented, including structural features and semantic features. Thirdly, an analysis prototype named SSdroid has been implemented to automatically extract SSBFs of security-sensitive operations. Finally, experiments on 9285 operations from both benign and malicious apps show that SSBFs are effective and usefulness. Our evaluation results suggest that the second-step behavior can greatly assist in Android malware detection.

关键词： Android malware Security-sensitive operations Static program analysis Classification

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A bipartite model for load balancing in grid computing environments

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中国高等学校学术文摘·计算机科学 2009年第4期3卷 503-523页

作者： Wenchao JIANG Matthias BAUMGARTEN Yanhong ZHOU Hai JIN School of Computer Science and Technology Hubei bioinformatics and molecular imaging key laboratoryHuazhong University of Science and TechnologyWuhan 430074China Information Engineering College of Faculty of Computing and Engineering University of UlsterShore RoadNewtownabbey BT37 0QBUK School of Computer Science and Technology Hubei bioinformatics and molecular imaging key laboratoryHuazhong University of Science and TechnologyWuhan 430074China

In this paper,a bipartite model for load balanchag (LB) in grid computing environments,called Transverse viewpoint-based Bi-Tier model (TBT),is *** can efficiently eliminate topology mismatching between overlay-and physical-networks during the load transfer *** an implementation of TBT,a novel LB policy called M~2ON (Min-cost and Max-flow Channel based Overlay Network) is *** M~2ON,the communication capability is denoted as M~2C (Min-cost and Max-flow Channel) which is obtained using a Labeled Tree Probing (LTP) *** computing capacity is denoted as the Idle Factor (IF) which is obtained from the semantic *** higher-and lower-level characteristics are combined into an Integrated Impacting Factor (IIF) using a Double Linear Inserting (DLI) *** on IIF,optimal topology matching can be achieved in the LB *** experiments and simulations have been performed and will be *** results show that M~2ON achieves more accurate topology matching with a minimum increment in the overall locating time yet achieving higher system performance as a whole.

关键词： grid computing load balancing (LB) min-cost and max-flow channel (M2C) topology mismatching labeled tree probing (LTP) double linear inserting (DLI)

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Numerical Investigations of a Class of Biological Models on Unbounded Domain

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Numerical Mathematics(Theory,Methods and Applications) 2019年第1期12卷 169-186页

作者： Qiumei Huang Dongfang Li Jiwei Zhang Beijing Institute for Scientific and Engineering Computing Beijing University of TechnologyBeijing 100124China School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratoryof Engineering Modeling and Scientific Computing Huazhong University of Science and TechnologyWuhan 430074China Beijing Computational Science Research Center Beijing1000193China

This paper is concerned with numerical computations of a class of biologi-cal models on unbounded spatial *** overcome the unboundedness of spatial domain,we first construct efficient local absorbing boundary conditions(LABCs)to re-formulate the Cauchy problem into an initial-boundary value(IBV)*** that,we construct a linearized finite difference scheme for the reduced IVB problem,and provide the corresponding error estimates and stability *** delay-dependent dynamical properties on the Nicholson’s blowflies equation and the Mackey-Glass equa-tion are numerically ***,numerical examples are given to demonstrate the efficiency of our LABCs and theoretical results of the numerical scheme.

关键词： Biological models artificial boundary method absorbing boundary conditions finite difference method stability,convergence

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Electronic band energy of a bent ZnO piezoelectric semiconductor nanowire

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Applied Mathematics and Mechanics(English Edition) 2020年第6期41卷 833-844页

作者： Wanli YANG Yuantai HU E.N.PAN Department of Mechanics Hubei Key Laboratory of Engineering Structural Analysis and Safety AssessmentHuazhong University of Science and TechnologyWuhan 430074China Computer Modeling and Simulation Group College of EngineeringUniversity of AkronAkronOhio 44325U.S.A.

The electric band energy variation in a bent piezoelectric semiconductor(PSC) nanowire of circular cross-section induced by the mechanical force is analyzed based on a six-band k · p method. The electric-mechanical fields are first obtained analytically in a cantilever bent PSC nanowire by solving the fully-coupled electro-mechanical equations. Then, the band energy is acquired numerically via the six-band *** considering further the nonlinear coupling between the piezoelectric and semiconducting quantities, the contribution of the redistribution carriers to the electric field is analyzed from the Gauss’ s law. Numerical examples are carried out for an n-type Zn O nanowire in different locations induced by an applied concentrated end force. They include the electric potential, heavy hole(HH), light hole(LH), spin-orbit split-off(SO),and conduction band(CB) edges along the axial and thickness directions. Our results show that the applied force has a significant effect on the band energies. For instance, on the bottom surface along the axial direction, the bandgaps near the fixed end are greater than those near the loading end, and this trend is reversed on the top surface. Moreover,at a fixed axial location, the energy level of the lower side can be enhanced by applying a bending force at the end. The present results could be of significant guidance to the electronic devices and piezotronics.

关键词： piezoelectric semiconductor(PSC) mechanical bending energy band ZnO

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TVIDS: Trusted Virtual IDS With SGX

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China Communications 2019年第10期16卷 133-150页

作者： Juan Wang Shirong Hao Yi Li Zhi Hong Fei Yan Bo Zhao Jing Ma Huanguo Zhang Key Laboratory of Aerospace Information Security and Trust Computing Ministry of EducationSchool of Cyber Science and EngineeringWuhan UniversityWuhan 430072HubeiChina School of Cyber Science and Engineering Wuhan UniversityWuhan 430072China Science and Technology on Information Assurance Laboratory Beijing 100072China

Network functions such as intrusion detection systems (IDS) have been increasingly deployed as virtual network functions or outsourced to cloud service providers so as to achieve the scalability and agility, and reducing equipment costs and operational cost. However, virtual intrusion detection systems (VIDS) face more serious security threats due to running in a shared and virtualized environment instead of proprietary devices. Cloud service providers or malicious tenants may illegally access and tamper with the policies, packet information, and internal processing states of intrusion detection systems, thereby violating the privacy and security of tenant’s networks. To address these challenges, we use Intel Software Guard Extensions (SGX) to build a Trusted Virtual Intrusion Detection System (TVIDS). For TVIDS, to prevent cloud service providers from accessing sensitive information about the users’ network, we build a trusted execution environment for security policy, packets processing, and internal state so that cloud service providers and other malicious tenants can’t access the protected code, policy, processing states, and packets information of the intrusion detection system. We implemented TVIDS on the basis of the Snort which is a famous open-source IDS and evaluated its results on real SGX *** results show that our method can protect the security of the virtual IDS and brings acceptable performance overhead.

关键词： network function virtualization intrusion detection system SGX trusted execution environment

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Attribute-Based Access Control Encryption

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IEEE Transactions on Dependable and Secure computing 2024年第3期22卷 2227-2242页

作者： Wang, Xiuhua Yu, Mengyang Wang, Yaohui Pi, Yinjia Xu, Peng Wang, Shuai Jin, Hai Han, Min Huazhong University of Science and Technology Hubei Key Laboratory of Distributed System Security School of Cyber Science and Engineering Wuhan430074 China State Key Laboratory of Cryptology Beijing100878 China Huazhong University of Science and Technology National Engineering Research Center for Big Data Technology and System Services Computing Technology and System Lab Hubei Key Laboratory of Distributed System Security Hubei Engineering Research Center on Big Data Security School of Cyber Science and Engineering Wuhan430074 China University of Electronic Science and Technology of China National Key Laboratory of Wireless Communications Chengdu611731 China Huazhong University of Science and Technology National Engineering Research Center for Big Data Technology and System School of Computer Science and Technology Cluster and Grid Computing Lab Services Computing Technology and System Lab Wuhan430074 China

The burgeoning complexity of communication necessitates a high demand for security. Access control encryption is a promising primitive to meet the security demand but the bulk of its constructions rely on formulating the access control policy with identities. Attribute-based access control policy in attribute-based encryption (ABE) is known to be more expressive without relying on enumerating identities. We propose a generic framework to build attribute-based access control encryption from ciphertext-policy ABE. Our instantiations prioritize different emphases on expressiveness and efficiency. The first instantiation supports multi-valued AND-gate access control structures, while the second supports the linear-secret-sharing access structure. Both are prototyped with efficiency validated empirically. © 2004-2012 IEEE.

关键词： Ciphertext

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Semi-Supervised Nuclei Instance Segmentation with Category-Adaptive Sampling and Region-Adaptive Attention

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Applied sciences (Switzerland) 2025年第9期15卷

作者： Li, Xunci Luo, Die Wei, Zimei Long, Junan Ye, Zhiwei School of Computer Science Hubei University of Technology Wuhan430068 China Hubei Provincial Key Laboratory of Green Intelligent Computing Power Network Hubei University of Technology Wuhan430068 China Faculty of Engineering Sciences University College London LondonWC1E 6BT United Kingdom

Cell nuclei instance segmentation plays a critical role in pathological image analysis. In recent years, fully supervised methods for cell nuclei instance segmentation have achieved significant results. However, in practical medical image processing, annotating dense cell nuclei at the instance level is often costly and time-consuming, making it challenging to acquire large-scale labeled datasets. This challenge has motivated researchers to explore ways to further enhance segmentation performance under limited labeling conditions. To address this issue, this paper proposes a network based on category-adaptive sampling and attention mechanisms for semi-supervised nuclei instance segmentation. Specifically, we design a category-adaptive sampling method that forces the model to focus on rare categories and dynamically adapt to different data distributions. By dynamically adjusting the sampling strategy, the balance of samples across different cell types is improved. Additionally, we propose a strong–weak contrast consistency method that significantly expands the perturbation space. Strong perturbations enhance the model’s ability to discriminate key nuclei features, while weak perturbations improve its robustness against noise and interference. Furthermore, we introduce a region-adaptive attention mechanism that dynamically assigns higher weights to key regions, guiding the model to prioritize learning discriminative features in challenging areas such as blurred or ambiguous cell boundaries. This improves the morphological accuracy of the segmentation masks. Our method effectively leverages the potential information in unlabeled data, thereby reducing reliance on large-scale, high-quality labeled datasets. Experimental results on public datasets demonstrate the effectiveness of our approach. © 2025 by the authors.

关键词： Image segmentation

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REQUIRED NUMBER OF ITERATIONS FOR SPARSE SIGNAL RECOVERY VIA ORTHOGONAL LEAST SQUARES

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Journal of Computational Mathematics 2023年第1期41卷 1-17页

作者： Haifeng Li Jing Zhang Jinming Wen Dongfang Li Henan Engineering Laboratory for Big Data Statistical Analysis and Optimal Control College of Mathematics and Information ScienceHenan Normal UniversityXinxiang 453007China College of Information Science and Technology Jinan UniversityGuangzhou 510632China School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and TechnologyWuhan 430074China

In countless applications,we need to reconstruct a K-sparse signal x∈R n from noisy measurements y=Φx+v,whereΦ∈R^(m×n)is a sensing matrix and v∈R m is a noise *** least squares(OLS),which selects at each step the column that results in the most significant decrease in the residual power,is one of the most popular sparse recovery *** this paper,we investigate the number of iterations required for recovering x with the OLS *** show that OLS provides a stable reconstruction of all K-sparse signals x in[2.8K]iterations provided thatΦsatisfies the restricted isometry property(RIP).Our result provides a better recovery bound and fewer number of required iterations than those proposed by Foucart in 2013.

关键词： Sparse signal recovery Orthogonal least squares(OLS) Restricted isometry property(RIP)

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Recognizing Malicious Behaviors of Chrome Extensions through Direct JavaScript Execution

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Wuhan University Journal of Natural sciences 2021年第1期26卷 89-101页

作者： FU Jianming HE Jia XE Mengfei MEI Xufen School of Cyber Science and Engineering Wuhan UniversityWuhan 430072HubeiChina Key Laboratory of Aerospace Information Security and Trusted Computing Wuhan UniversityWuhan 430072HubeiChina

There are a large number of extensions with many users in Google Chrome,which greatly enriches the functionalities of ***,due to inadequate security auditing,vulnerable updating mechanisms and time-delayed maintenance of Chrome Web Store,the store becomes a platform for attackers to distribute malicious *** static analysis methods can hardly detect obfuscated codes and dynamic codes injected by extensions,while dynamic detection methods have low coverage due to the need to meet various constraints when extensions are being *** propose a method to analyze Chrome extension behaviors dynamically based on direct execution of Java Script(JS).The core idea of this method is to convert the analysis of the whole extension into the analysis of each JS in the extension,bypassing the constraints(***,region,URL)of the extension itself,and improving the coverage of *** analysis of more than 44000 extensions showed that the method can effectively identify predefined *** them,20 extensions had access to malicious domains,1113 extensions injected advertisements and 381 extensions collected users’passwords or *** the same time,the number of URL requests obtained from this method is 177893,which is 52.44%more than that from traditional dynamic analysis method.

关键词： Chrome extension malicious extension browser security behavior monitoring

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