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ABDKS:attribute-based encryption with dynamic keyword search in fog computing

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Frontiers of Computer Science 2021年第5期15卷 187-195页

作者： fei meng Leixiao CHENG Mingqiang WANG School of Mathematics Shandong UniversityJinan 250100China Key Laboratory of Cryptologic Technology and Information Security Ministry of EducationJinan 250100China School of Mathematical Sciences Fudan UniversityShanghai 200433China

Attribute-based encryption with keyword search(ABKS)achieves both fine-grained access control and keyword ***,in the previous ABKS schemes,the search algorithm requires that each keyword to be identical between the target keyword set and the ciphertext keyword set,otherwise the algorithm does not output any search result,which is not conducive to ***,the previous ABKS schemes are vulnerable to what we call a peer-decryption attack,that is,the ciphertext may be eavesdropped and decrypted by an adversary who has sufficient authorities but no information about the ciphertext *** this paper,we provide a new system in fog computing,the ciphertext-policy attribute-based encryption with dynamic keyword search(ABDKS).In ABDKS,the search algorithm requires only one keyword to be identical between the two keyword sets and outputs the corresponding correlation which reflects the number of the same keywords in those two *** addition,our ABDKS is resistant to peer-decryption attack,since the decryption requires not only sufficient authority but also at least one keyword of the *** that,the ABDKS shifts most computational overheads from resource constrained users to fog *** security analysis shows that the ABDKS can resist Chosen-Plaintext Attack(CPA)and Chosen-Keyword Attack(CKA).

关键词： access control attribute-based encryption keyword search fog computing outsourcing

How does a strong surrounding magnetic field influence the evolution of a supernova remnant?

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Research in Astronomy and Astrophysics 2019年第9期19卷 21-28页

作者： Dan Wu meng-fei Zhang College of Information Science and Technology Beijing Normal UniversityBeijing100875China University of Chinese Academy of Sciences Beijing100049China Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing100101China

We simulate the evolution of supernova remnants(SNRs) in a strong magnetic field. Usually,supernovae explode in a normal interstellar medium with magnetic field of no more than 50 μG, which has been well studied. However, the surrounding magnetic field will be much stronger in some situations, such as in a galactic center. Therefore, we try to explore these situations. The simulations show that a strong magnetic field of 1 mG will align the motion of ejecta in a way similar to a jet. The ejecta propagating perpendicularly to the magnetic field will be reflected and generate a strong reverse shock. When the reverse shock converges in the explosion center, it will more or less flow along the central magnetic field. Finally,most of the ejecta will propagate parallel to the magnetic field.

关键词： ISM:supernova remnants ISM:magnetic fields magnetohydrodynamics

Novel matched filtering method and its application in radar system

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Journal of Systems Engineering and Electronics 2010年第5期21卷 759-762页

作者： fei meng Lianggui Xie Raohui Li Beijing Institute of Radio Measurement Beijing 100039 R R. China China Aerospace Science and Industry Corporation Beijing 100048 R R. China

The method of using a narrowband filter to realize matched filtering is derived.A novel method of using spectrum sampling to realize matched filtering is presented,and the method can conquer the disadvantages that the narrowband filter cannot adopt the adaptive scheduling of phased array radars and realize matched filtering for several waveforms.A novel error extraction method is proposed,which uses a time division multipath method to realize the intermediate frequency *** method can save lots of space for vehicle-born radar systems,reduce the influence of amplitude and phase distortion caused by devices,and enhance the system *** results show that the spectrum sampling method is applicable,and the implementation of frequency spectrum sampling is elaborated.

关键词： radar matched filtering spectrum sampling intermediate frequency error extraction.

Simulation of the effects of different substrates, temperature,and substrate roughness on the mechanical properties of Al_2O_3 coating as tritium penetration barrier

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Nuclear Science and Techniques 2019年第4期30卷 80-90页

作者： Ze Liu fei meng Liang-Bi Yi Key Laboratory for Radiation Physics and Technology of Ministry of Education Institute of Nuclear Science and Technology Sichuan University Chengdu Youfang Technology Co. Ltd Southwestern Institute of Physics

Residual thermal stress in the system is a serious problem that affects the application of tritium permeation barrier coatings in fusion reactors. The stress not only determines the adhesion between coating and substrate, but also changes the properties of the material. In this study,finite element analysis was used to investigate the relationship between the residual thermal stress and the mechanical properties of Al_2O_3 tritium penetration barrier systems. Moreover, the residual thermal stress influenced by factors such as different substrates, temperature, and substrate roughness was also analyzed. The calculation showed that the hardness and elastic modulus increased with increasing compressive stress. However, the hardness and elastic modulus decreased with increasing tensile stress. The systems composed of Al_2O_3 coatings and different substrates exhibited different trends in mechanical properties. As the temperature increased, the hardness and the elastic modulus increased in an Al_2O_3/316 L stainless steel system; the trend was opposite in an Al_2O_3/Si *** from this, the roughness of the substrate surface in the system could magnify the change in hardness and elastic modulus of the coating. Results showed that all these factors led to variation in the mechanical properties of Al_2O_3 tritium permeation barrier systems. Thus, thedetailed reasons for the changes in mechanical properties of these materials need to be analyzed.

关键词： Finite element analysis Thermal stress Mechanical properties Al2O3 tritium penetration barrier systems Nanoindentation

Technical advancements and significance of circumlunar return and reentry spacecraft

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Science China(Technological Sciences) 2015年第4期58卷 738-745页

作者： YANG meng fei ZHANG Wu PENG Jing ZHANG Gao China Academy of Space Technology Institute of Spacecraft System Engineering China Academy of Space Technology

As one of the vital steps in the 3rd phase of China＇s lunar exploration program （CLEP）, the circumlunar return and reentry spacecraft, developed by China Academy of Space Technology （CAST）, is used to demonstrate the key technologies of by- per-speed return and reentry spacecraft. The system configuration and flight process are presented in this paper, as well as the analysis of mission characteristics, the key technologies and the technical advancement during the R＆D progress. The significance of circumlunar return and reentry spacecraft is given at the end.

关键词： circumlunar return skip reentry technical advancement China's lunar exploration program (CLEP)

High Dynamic Bounding and Jumping Motion of Quadruped Robot Based on Stable Optimization Control

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Journal of Bionic Engineering 2024年第1期21卷 101-111页

作者： Sai Gu fei meng Botao Liu Junyao Gao Qiang Huang School of Mechatronical Engineering Beijing Institute of Technology100081 BeijingChina Key Laboratory of Biomimetic Robots and Systems Ministry of EducationBeijing 100081China

Aiming at the environment such as ravines and obstacles that may be encountered in the actual movement,this paper proposes a method for optimizing the bounding and jumping motion based on the ground touching force trajectory and the air motion trajectory of the quadruped *** method of optimizing the ground reaction force according to the speed of the demand and the height of the jump,and adjusting the stance and swing time according to the relationship of dynamics and momentum *** the same time,under the constraints of dynamics and energy consumption of the robot system,considering the jumping distance and height,a method for optimizing the air trajectory of bounding and jumping is *** switching and landing stability control are also ***,the experimental results show that the quadruped robot has strong bounding and jumping ability,and has achieved stable bounding movement and forward jump movement of 0.8 m.

关键词： Quadruped robot High dynamic motion control-Periodic limit cycle Trajectory optimization

Defining two subpopulations of marginal zone B cells

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Cellular & Molecular Immunology 2024年第4期21卷 412-413页

作者： Xiaojing Liu fei-Long meng Key Laboratory of RNA Science and Engineering Shanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghai200031China

Marginal zone(MZ)B cells,which are composed of heterogeneous subpopulations,are participate in the rapid response to *** et *** that MZ B cells can be divided into two distinct subpopulations based on CD80 *** two sub... 详细信息

关键词： expression. subpopulations al.

Smart and fast reinforcement design for anti-dip bedding rock slopes

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第11期15卷 2943-2953页

作者： Yun Zheng Congxin Chen fei meng Xiaodong Fu Wei Yuan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China School of Civil Engineering and Architecture Wuhan University of TechnologyWuhan430070China Key Laboratory of Roads and Railway Engineering Safety Control of Ministry of Education Shijiazhuang Tiedao UniversityShijiazhuang050043China

Rock slopes are usually reinforced by a number of rock bolts due to the high efficiency and low ***,where should the rock bolts be installed is still a troublesome *** anti-dip bedding rock slopes(ABRSs),the installation position of rock bolts is a controlling factor that determines the reinforcement *** this work,a theoretical method is firstly proposed for assessing the stability of ABRSs reinforced by rock bolts using a limit equilibrium model.A comparison of theoretical calculations and numerical results was conducted to test the correctness of the theoretical *** on the stability assessment of ABRSs,we introduce adaptive moment estimation method(Adam)to optimize the installation location of rock *** Adam optimizer,the optimal layout of rock bolts with the maximum factor of safety can be determined,and the factor of safety of the slope increases by about 25%using the same amount of rock bolts but with different installation *** proposed method enables the fast stability analysis and supporting design for reinforced ABRSs,which paves the way to smart supporting design of slopes.

关键词： Rock slopes Toppling failure Rock bolts Stability assessment Smart analysis

Task-space Whole-body Control with Variable Contact Force Control for Position-controlled Humanoid Adaptation to Unknown Disturbance

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Journal of Bionic Engineering 2023年第5期20卷 2069-2087页

作者： Zelin Huang Chencheng Dong Zhangguo Yu Xuechao Chen fei meng Qiang Huang School of Mechatronical Engineering Beijing Institute of TechnologyBeijing100081China Key Laboratory of Biomimetic Robots and Systems Ministry of EducationBeijing100081China

Whole-body control is beneficial for improving the disturbance adaptation of humanoid robots,since it can simultaneously optimize desired joint torque,joint acceleration,and contact force while considering whole-body dynamics and other physical ***,the lack of torque feedback information prevents the position-controlled humanoids from utilizing whole-body control directly,because it enhances the difficulty of guaranteeing desired contact force which is important for maintaining *** this paper,a whole-body control that integrates task-space inverse dynamics and variable contact force control is proposed for position-controlled humanoids to enhance the robot’s adaptability toward the unknown *** task-space inverse dynamics generates the desired joint acceleration and contact force with the consideration of whole-body dynamics and other limits to track the *** variable contact force control modifies references related to Center of Mass(CoM)and end effectors to ensure reasonable contact force tracking performance,thereby assuring good tracking performance of CoM and momentum to maintain robot *** and experiments of balancing and walking under unknown disturbance have been successfully conducted on a position-controlled humanoid robot,BHR-7P3,with the proposed method.

关键词： Whole-body control Contact force Admittance control Humanoid robot