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CToMP: a cycle-task-oriented memory protection scheme for unmanned systems

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Science China(Information Sciences) 2024年第6期67卷 399-417页

作者： Chengyan ma Ning XI Di LU Yebo FENG Jianfeng ma School of Cyber Engineering Xidian University School of Computer Science and Technology Xidian University Department of Computer and Information Science University of Oregon

Memory corruption attacks(MCAs) refer to malicious behaviors of system intruders that modify the contents of a memory location to disrupt the normal operation of computing systems, causing leakage of sensitive data or perturbations to ongoing processes. Unlike general-purpose systems, unmanned systems cannot deploy complete security protection schemes, due to their limitations in size, cost and *** in unmanned systems are particularly difficult to defend against. Furthermore, MCAs have diverse and unpredictable attack interfaces in unmanned systems, severely impacting digital and physical sectors. In this paper, we first generalize, model and taxonomize MCAs found in unmanned systems currently, laying the foundation for designing a portable and general defense approach. According to different attack mechanisms,we found that MCAs are mainly categorized into two types — return2libc and return2shellcode. To tackle return2libc attacks, we model the erratic operation of unmanned systems with cycles and then propose a cycle-task-oriented memory protection(CToMP) approach to protect control flows from tampering. To defend against return2shellcode attacks, we introduce a secure process stack with a randomized memory address by leveraging the memory pool to prevent Shellcode from being executed. Moreover, we discuss the mechanism by which CTo MP resists the return-oriented programming(ROP) attack, a novel variant of return2libc attacks. Finally, we implement CTo MP on CUAV V5+ with Ardupilot and Crazyflie. The evaluation and security analysis results demonstrate that the proposed approach CTo MP is resilient to various MCAs in unmanned systems with low footprints and system overhead.

关键词： unmanned system memory corruption attack memory protection system security randomized memory address

Aero-structural design of joined-wing aircraft based on high-fidelity model

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Chinese Journal of Aeronautics 2024年第4期37卷 363-377页

作者： Cheng HE Fengjiang ZHAN Luchuang ma Gang CHEN Jianying ma Unmanned Air Vehicle Research Institute Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Advanced Technology for Small and Medium-sized UAV Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China Aerospace System Engineering Shanghai Shanghai 201108China

The joined-wing configuration reduces induced drag and structural weight by connecting the rear wing to the front *** addition,the rear wing can replace the role of the horizontal tail of a conventional aircraft,thus eliminating the aerodynamic drag and weight associated with the horizontal *** particular shape creates a highly coupled relationship between aerodynamics and structure,which must be fully considered during the overall design process to enhance aircraft *** this research,an aero-structural design model of the joined-wing aircraft is constructed based on high-fidelity computational fluid dynamics and structural finite element *** model is able to obtain accurate aerodynamic loads for the non-planar wing and to simulate the statically indeterminate structure of the closed wing *** influence of the joined-wing shape parameters on the aerodynamic and structural disciplines,as well as the influence of geometric nonlinear characteristics,deformation constraints and buckling constraints on the structural weight are all taken into *** model is applied to complete the aero-structural design optimization of a high-altitude long-endurance joined-wing aircraft,and wind tunnel tests are *** test results verify the credibility of the design model proposed and the validity of the design environment.

关键词： Joined-wing configuration Aircraft design Aero-structural design Finite element Wind tunnel test

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人工智能在青光眼图像诊断中的应用

中华实验眼科杂志 2020年第5期38卷 438-441页

作者：马婧一(综述) 李元媛原慧萍(审校) 哈尔滨医科大学 150086 哈尔滨医科大学附属第二医院眼科 150086

随着计算机技术及图像识别技术的不断发展,人工智能(AI)在医学领域的应用不断拓展,对于利用机器学习及深度学习诊疗眼科疾病的研究日益增多。青光眼作为首位不可逆性致盲眼病,早期诊断、及时治疗对于维持患者视功能和生活质量至关重要... 详细信息

随着计算机技术及图像识别技术的不断发展,人工智能(AI)在医学领域的应用不断拓展,对于利用机器学习及深度学习诊疗眼科疾病的研究日益增多。青光眼作为首位不可逆性致盲眼病,早期诊断、及时治疗对于维持患者视功能和生活质量至关重要。目前,AI在青光眼诊疗过程中的应用主要集中在青光眼辅助诊断图像,如眼底照相、视野、光相干断层扫描(OCT)等的结合,研究者们通过建立AI模型,对图像检查结果进行分割、分类及预测,达到辅助诊断及预测青光眼进展的目的。随着算法、技术的不断发展,诊断的准确性、灵敏度及特异性都在日趋完善。青光眼的诊治需要综合考量多方面辅助检查结果,因此,筛选高质量的数据并开发更加系统、全面的AI模型仍待探索。目前与青光眼相关的眼前节辅助诊断AI模型屈指可数,因此我们可以着手研究与超声生物显微镜和眼前节OCT相关的机器、深度学习模型。本文就AI在青光眼图像诊断中应用的研究进展进行综述。

关键词：青光眼人工智能图像诊断

Unconfined compressive strength and failure behaviour of completely weathered granite from a fault zone

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Journal of Mountain Science 2024年第6期21卷 2140-2158页

作者： DU Shaohua ma Jinyin ma Liyao ZHAO Yaqian School of Civil Engineering and Architecture Henan University of Science and TechnologyLuoyang 471023China School of Resources and Safety Engineering Central South UniversityChangsha 410083China China Railway 18th Bureau Group Co. LtdTianjin 300222 China China General Nuclear Power Corporation Shenzhen 518031China

Understanding the strength characteristics and deformation behaviour of the tunnel surrounding rock in a fault zone is significant for tunnel stability *** this study,a series of unconfined compression tests were conducted to investigate the mechanical characteristics and failure behaviour of completely weathered granite(CWG)from a fault zone,considering with height-diameter(h/d)ratio,dry densities(ρd)and moisture contents(ω).Based on the experimental results,a regression mathematical model of unconfined compressive strength(UCS)for CWG was developed using the Multiple Nonlinear Regression method(MNLR).The research results indicated that the UCS of the specimen with a h/d ratio of 0.6 decreased with the increase ofω.When the h/d ratio increased to 1.0,the UCS increasedωwith up to 10.5%and then ***ρd is conducive to the improvement of the UCS at anyω.The deformation and rupture process as well as final failure modes of the specimen are controlled by h/d ratio,ρd andω,and the h/d ratio is the dominant factor affecting the final failure mode,followed byωandρ*** specimens with different h/d ratio exhibited completely different fracture mode,i.e.,typical splitting failure(h/d=0.6)and shear failure(h/d=1.0).By comparing the experimental results,this regression model for predicting UCS is accurate and reliable,and the h/d ratio is the dominant factor affecting the UCS of CWG,followed byρd and thenω.These findings provide important references for maintenance of the tunnel crossing other fault fractured zones,especially at low confining pressure or unconfined condition.

关键词： Fault fracture zone Completely weathered granite(CWG) Unconfined compression strength(UCS) Multiple nonlinear regression model

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算法建模发展解析

统计研究 2009年第2期26卷 58-61页

作者：马景义吴喜之谢邦昌中央财经大学统计学院中国人民大学统计学院辅仁大学统计信息学系暨应用统计所中华资料采矿协会

Breiman并没有算法建模的一个完整体系,而且其许多研究都以工作论文的形式出现,对于这些方法机理的解析度都不够。本文在研究Breiman自1978年至2002年的论文和著作的基础上,概括出算法建模思想形成中的两个重要内容:建模目的,组合算法。

关键词：算法建模贝叶斯规则预测误差组合方法

Mitigate noisy data for smart IoT via GAN based machine unlearning

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Science China(Information Sciences) 2024年第3期67卷 62-78页

作者： Zhuo ma Yilong YANG Yang LIU Xinjing LIU Jianfeng ma School of Cyber Engineering Xidian University State Key Laboratory of Integrated Services Networks (ISN)

With the development of IoT applications, machine learning dramatically improves the utility of variable IoT systems such as autonomous driving. Although the pretrain-finetune framework can cope well with data heterogeneity in complex IoT scenarios, the data collected by sensors often contain unexpected noisy data, e.g., out-of-distribution(OOD) data, which leads to the reduced performance of fine-tuned models. To resolve the problem, this paper proposes Mu GAN, a method that can mitigate the side-effect of OOD data via the generative adversarial network(GAN)-based machine unlearning. Mu GAN follows a straightforward but effective idea to mitigate the performance loss caused by OOD data, i.e., “flashbacking” the model to the condition where OOD data are excluded from model training. To achieve the goal, we design an adversarial game, where a discriminator is trained to identify whether a sample belongs to the training set by observing the confidence score. Meanwhile, a generator(i.e., the target model) is updated to fool the discriminator into believing that the OOD data are not included in the training set but others do. The experimental results show that benefiting from the high unlearning rate(more than 90%) and retention rate(99%), Mu GAN succeeds in lowering the model performance degradation caused by OOD data from 5.88% to 0.8%.

关键词： machine unlearning generative adversarial network out of distribution data Internet of Thing neural network

Identification of the cytochrome P450s responsible for the biosynthesis of two types of aporphine alkaloids and their de novo biosynthesis in yeast

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Journal of Integrative Plant Biology 2024年第8期66卷 1703-1717页

作者： Qishuang Li Xiang Jiao Xinyi Li Wenlong Shi Ying ma Xiangmei Tan jingyi Gan Jimei Liu Jian Yang Jian Wang Baolong Jin Tong Chen Ping Su Yujun Zhao Yifeng Zhang Jinfu Tang Guanghong Cui Yun Chen Juan Guo Luqi Huang School of Traditional Chinese Pharmacy China Pharmaceutical UniversityNanjing 211198China State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs National Resource Center for Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijing 100700China Department of Life Sciences Chalmers University of TechnologyGothenburg SE-41296Sweden State Key Laboratory of Natural and Biomimetic Drugs School of Pharmaceutical SciencesPeking UniversityBeijing 100191China State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaThe Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China

Aporphine alkaloids have diverse pharmacological activities;however,our understanding of their biosynthesis is relatively *** studies have classified aporphine alkaloids into two categories based on the configuration and number of substituents of the D-ring and have proposed preliminary biosynthetic pathways for each *** this study,we identified two specific cytochrome P450 enzymes(CYP80G6 and CYP80Q5)with distinct activities toward(S)-configured and(R)-configured substrates from the herbaceous perennial vine Stephania tetrandra,shedding light on the biosynthetic mechanisms and stereochemical features of these two aporphine alkaloid ***,we characterized two CYP719C enzymes(CYP719C3 and CYP719C4)that catalyzed the formation of the methylenedioxy bridge,an essential pharmacophoric group,on the A-and D-rings,respectively,of aporphine *** the functional characterization of these crucial cytochrome P450 enzymes,we reconstructed the biosynthetic pathways for the two types of aporphine alkaloids in budding yeast(Saccharomyces cerevisiae)for the de novo production of compounds such as(R)-glaziovine,(S)-glaziovine,and *** study provides key insight into the biosynthesis of aporphine alkaloids and lays a foundation for producing these valuable compounds through synthetic biology.

关键词： aporphine alkaloids biosynthesis CYP719C CYP80 engineered yeast

Enhancing capacitive deionization performance and cyclic stability of nitrogen-doped activated carbon by the electro-oxidation of anode materials

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Chinese Journal of Chemical Engineering 2024年第5期69卷 23-33页

作者： Xiaona Liu Baohua Zhao Yanyun Hu Luyue Huang Jingxiang ma Shuqiao Xu Zhonglin Xia Xiaoying ma Shuangchen ma School of Environmental Science and Engineering North China Electric Power UniversityBaoding 071003China Huadian Zhengzhou machinery Design and Research Institute Co. LtdZhengzhou 450002China Huadian Inner Mongolia Energy Co. Ltd.Baotou Power Generation BranchBaotou 014013China

Electrode materials with high desalination capacity and long-term cyclic stability are the focus of capacitive deionization(CDI) community. Understanding the causes of performance decay in traditional carbons is crucial to design a high-performance material. Based on this, here, nitrogen-doped activated carbon(NAC) was prepared by pyrolyzing the blend of activated carbon powder(ACP) and melamine for the positive electrode of asymmetric CDI. By comparing the indicators changes such as conductivity, salt adsorption capacity, pH, and charge efficiency of the symmetrical ACP-ACP device to the asymmetric ACP-NAC device under different CDI cycles, as well as the changes of the electrochemical properties of anode and cathode materials after long-term operation, the reasons for the decline of the stability of the CDI performance were revealed. It was found that the carboxyl functional groups generated by the electro-oxidation of anode carbon materials make the anode zero-charge potential(E_(pzc)) shift positively,which results in the uneven distribution of potential windows of CDI units and affects the adsorption capacity. Furthermore, by understanding the electron density on C atoms surrounding the N atoms, we attribute the increased cyclic stability to the enhanced negativity of the charge of carbon atoms adjacent to quaternary-N and pyridinic-oxide-N.

关键词： Anodic oxidation Capacitive deionization Cyclic stability N-doping

A combined Liouville integrable hierarchy associated with a fourth-order matrix spectral problem

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Communications in Theoretical Physics 2024年第7期76卷 1-8页

作者： Wen-Xiu ma Department of mathematics Zhejiang Normal UniversityJinhua 321004China Department of mathematics King Abdulaziz UniversityJeddah 21589Saudi Arabia Department of mathematics and Statistics University of South Florida TampaFL 33620-5700United States of America material Science Innovation and Modelling Department of Mathematical SciencesNorth-West UniversityMafikeng CampusMmabatho 2735South Africa

This paper aims to propose a fourth-order matrix spectral problem involving four potentials and generate an associated Liouville integrable hierarchy via the zero curvature formulation.A bi-Hamiltonian formulation is furnished by applying the trace identity and a recursion operator is explicitly worked out,which exhibits the Liouville integrability of each model in the resulting *** specific examples,consisting of novel generalized combined nonlinear Schrodinger equations and modified Korteweg-de Vries equations,are given.

关键词： integrable hierarchy Hamiltonian structure zero curvature equation Lax pair matrix spectral problem

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