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Real-Time 3D Ultrasound Imaging System Based on a Hybrid Reconstruction Algorithm

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Chinese Journal of Electronics 2024年第1期33卷 245-255页

作者： yifei LYU Yu SHEN Mingbo ZHANG Junchen WANG School of Mechanical Engineering and Automation Beihang University The First Medical Center General Hospital of Chinese PLA

As a safe and convenient imaging technology in clinical routine diagnosis, ultrasound imaging can provide real-time 2D images of internal tissues and organs. To realize real-time 3D image reconstruction, pixel nearest neighbor interpolation(PNN) reconstruction algorithm and Bezier interpolation algorithm are combined into a hybrid reconstruction algorithm. On this basis, a real-time interactive 3D ultrasound imaging system is *** temporal calibration and spatial calibration, the six degrees of freedom poses of 2D ultrasound images can be accurately collected. The 3D volume reconstructed by the proposed 3D reconstruction algorithm is visualized by volume rendering. A multi-thread software system allows parallel operation of data acquisition, 3D reconstruction,volume visualization and other functions. 3D imaging experiments on a 3D printing femur model, a neck phantom and the neck of human volunteers were performed for systematic evaluation. When the reconstruction voxel size was set to be(0.53 mm3, 1.03 mm3, 1.53 mm3), the reconstruction errors of the femur and trachea model were respectively(0.23 mm, 0.31 mm, 0.56 mm) and(0.62 mm, 0.88 mm, 1.4. mm). Clinical feasibility was demonstrated by application of the 3D ultrasound imaging on the neck of human volunteers.

关键词： Interpolation Three-dimensional displays Ultrasonic imaging Imaging Data visualization Reconstruction algorithms Real-time systems

Effects of retained dry material on the impact,overflow and landing dynamics

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3629-3640页

作者： Jun Fang yifei Cui Haiming Liu State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijingChina Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong KongChina

During long-term operation,the performance of obstacles would be changed due to the material accumulating upslope the ***,the effects of retained material on impact,overflow and landing dynamics of granular flow have not yet been *** address this gap,physical flume tests and discrete element simulations are conducted considering a range of normalized deposition height h0/H from 0 to 1,where h0 and H represent the deposition height and obstacle height,*** analytical model is modified to evaluate the flow velocity and flow depth after interacting with the retained materials,which further serve to calculate the peak impact force on the ***,the computed impact forces successfully predict the experimental results when a≥25°.In addition,the results indicate that a higher h0/H leads to a lower dynamic impact force,a greater landing distance L,and a larger landing coefficient Cr,where Cr is the ratio of slope-parallel component of landing velocity to flow velocity just before *** to the existing overflow model,the measured landing distance L is underestimated by up to 30%,and therefore it is insufficient for obstacle design when there is retained ***,the recommended Cr in current design practice is found to be nonconservative for estimating the landing velocity of geophysical *** study provides insightful scientific basis for designing obstacles with deposition.

关键词： Granular flow Obstacle deposition Impact Overflow Landing

Re-entry rocket basic flow characteristics and thermal environment of different retro-propulsion modes

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Chinese Journal of Aeronautics 2024年第7期37卷 190-203页

作者： yifei SU Peijie SUN Yangwen CUI Guigao LE School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China Shanghai Institute of Aerospace System Engineering Shanghai 200000China Southwest Institute of Technology and Engineering Chongqing 400039China

During the supersonic re-entry of multi-nozzle heavy rockets into the atmosphere,the basic flow state becomes increasingly complex due to the coupling effect between the retropropulsion plumes and the freestream.A numerical method using the hybrid Reynolds-Averaged Navier-Stokes and Large Eddy Simulation(RES)method and discrete coordinate method is developed to accurately estimate the thermal *** addition,finite rate chemical kinetics is used to calculate the afterburning *** numerical results agree well with wind tunnel data,which confirms the validity and accuracy of the numerical *** are conducted for the heavy carrier rocket re-entry from 53.1 km to 39.5 km altitude with 180°angle of attack by using three different Supersonic Retro-Propulsion(SRP)*** numerical results reveal that these three SRP flow fields are all Short Penetration Models(SPM).As the re-entry altitudes decrease,both the plume-plume interaction and the plume-freestream interaction become *** highest temperatures in the plume shear layers of the three SRP modes increase by 8.36%,7.33%and 6.92%respectively after considering afterburning reactions,and all occur at a reentry altitude of 39.5 *** the rocket re-enters the atmosphere,the maximum heat flux on the rocket base plate of three SRP modes stabilizes at 290,170 and 200 kW/m^(2) respectively,but the maximum heat flux on the side wall increases *** the altitude declines to 39.5 km,the extreme heat flux of the three modes increase by 84.16%,4..4.%and 62.97%respectively compared to that at 53.1 km.

关键词： Re-entry rocket Multi-nozzle Supersonic retro propulsion Thermal environment Afterburning effect

Optimization of Random Feature Method in the High-Precision Regime

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1490-1517页

作者： Jingrun Chen Weinan E yifei Sun School of Mathematical Sciences and Suzhou Institute for Advanced Research Suzhou 215006JiangsuChina University of Science and Technology of China Hefei 230026AnhuiChina Center for Machine Learning Research and School of Mathematical Sciences Peking UniversityBeijing 100871China AI for Science Institute Beijing 100084China School of Mathematical Sciences Soochow UniversitySuzhou 215006JiangsuChina

Machine learning has been widely used for solving partial differential equations(PDEs)in recent years,among which the random feature method(RFM)exhibits spectral accuracy and can compete with traditional solvers in terms of both accuracy and ***,the optimization problem in the RFM is more difficult to solve than those that arise in traditional *** the broader machine-learning research,which frequently targets tasks within the low-precision regime,our study focuses on the high-precision regime crucial for solving *** this work,we study this problem from the following aspects:(i)we analyze the coeffcient matrix that arises in the RFM by studying the distribution of singular values;(ii)we investigate whether the continuous training causes the overfitting issue;(ii)we test direct and iterative methods as well as randomized methods for solving the optimization *** on these results,we find that direct methods are superior to other methods if memory is not an issue,while iterative methods typically have low accuracy and can be improved by preconditioning to some extent.

关键词： Random feature method(RFM) Partial differential equation(PDE) Least-squares problem Direct method Iterative method

Invasion of fall armyworm led to the succession of maize pests in Southwest China

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Journal of Integrative Agriculture 2024年第4期23卷 1300-1314页

作者： Zezheng Fan yifei Song Shengyuan Zhao Kongming Wu Agricultural Information Institute Chinese Academy of Agricultural SciencesBeijing 100081China Guangdong Laboratory for Lingnan Modern Agriculture Guangzhou 510642China State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijing 100193China

The invasive fall armyworm Spodoptera frugiperda(***)invaded Asia in 2018,colonizing the tropical and southern subtropical regions as well as migrating with the monsoons into Northeast Asia during spring and *** has resulted in widespread infestations,with significant impacts on maize production in various Asian *** studies have shown that the invasion of this pest can alter the species relationships of maize pests,but the actual impact on maize pest management is still *** study investigated the changes in maize pest occurrence and pesticide use in the annual breeding areas of *** in Yunnan Province and the Guangxi Zhuang Autonomous Region of China during 2017-2021,based on surveys and interviews with small farmers in maize *** results showed that *** has emerged as the dominant species among maize pests after invasion and colonization,replacing traditional pests such as Ostrinia furnacalis,Spodoptera litura,Agrotis ypsilon,and Rhopalosiphum *** variety of pesticides used for maize pest control has changed from chlorpyrifos,lambda-cyhalothrin,and acetamiprid to emamectin benzoate-based pesticides with high effectiveness against ***,the frequency of maize pest chemical applications has increased from an average of 5.88 to 7.21 times per season,with the amounts of pesticides used in summer and autumn maize being significantly higher than in winter and spring maize,thereby increasing application costs by more than 35%.The results of this study clarified the impact of *** invasion on maize pest community succession and chemical pesticide use in tropical and south subtropical China,thereby providing a baseline for modifying the regional control strategies for maize pests after the invasion of this relatively new pest.

关键词： Spodoptera frugiperda annual breeding region sweet waxy corn economic evaluation

Emerging role of galectin 3 in neuroinflammation and neurodegeneration

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Neural Regeneration Research 2024年第9期19卷 2004-2009页

作者： Brian M.Lozinski Khanh Ta yifei Dong Department of Clinical Neuroscience University of CalgaryCalgaryABCanada Deparment of Biochemistry Microbiology&ImmunologyUniversity of SaskatchewanSaskatoonSKCanada

Neuroinflammation and neurodegeneration are key processes that mediate the development and progression of neurological ***,the mechanisms modulating these processes in different diseases remain incompletely *** in single cell based multi-omic analyses have helped to identify distinct molecular signatures such as Lgals3 that is associated with neuroinflammation and neurodegeneration in the central nervous system(CNS).Lgals3 encodes galectin-3(Gal3),aβ-galactoside and glycan binding glycoprotein that is frequently upregulated by reactive microglia/macrophages in the CNS during various neurological *** Gal3 has previously been associated with non-CNS inflammatory and fibrotic diseases,recent studies highlight Gal3 as a prominent regulator of inflammation and neuroaxonal damage in the CNS during diseases such as multiple sclerosis,Alzheimer’s disease,and Parkinson’s *** this review,we summarize the pleiotropic functions of Gal3 and discuss evidence that demonstrates its detrimental role in neuroinflammation and neurodegeneration during different neurological *** also consider the challenges of translating preclinical observations into targeting Gal3 in the human CNS.

关键词： Alzheimer’s disease Galectin 3 microglia multiple sclerosis neurodegeneration neuroinflammation Parkinson’s disease therapeutics

CCM-FL:Covert communication mechanisms for federated learning in crowd sensing IoT

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Digital Communications and Networks 2024年第3期10卷 597-608页

作者： Hongruo Zhang yifei Zou Haofei Yin Dongxiao Yu Xiuzhen Cheng Institute of Intelligent Computing School of Computer Science and TechnologyShandong UniversityQingdao266237China

The past decades have witnessed a wide application of federated learning in crowd sensing,to handle the numerous data collected by the sensors and provide the users with precise and customized ***,how to protect the private information of users in federated learning has become an important research *** with the differential privacy(DP)technique and secure multiparty computation(SMC)strategy,the covert communication mechanism in federated learning is more efficient and energy-saving in training the ma-chine learning *** this paper,we study the covert communication problem for federated learning in crowd sensing Internet-of-Things *** from the previous works about covert communication in federated learning,most of which are considered in a centralized framework and experimental-based,we firstly proposes a centralized covert communication mechanism for federated learning among n learning agents,the time complexity of which is O(log n),approximating to the optimal ***,for the federated learning without parameter server,which is a harder case,we show that solving such a problem is NP-hard and prove the existence of a distributed covert communication mechanism with O(log logΔlog n)times,approximating to the optimal solution.Δis the maximum distance between any pair of learning *** analysis and nu-merical simulations are presented to show the performance of our covert communication *** hope that our covert communication work can shed some light on how to protect the privacy of federated learning in crowd sensing from the view of communications.

关键词： Covert communications Federated learning Crowd sensing SINR model

Enhancing AI System Privacy:An Automatic Tool for Achieving GDPR Compliance in NoSQL Databases

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Computers, Materials & Continua 2024年第7期80卷 217-234页

作者： yifei Zhao Zhaohui Li Siyi Lv College of Cyber Science Nankai UniversityTianjin300350China

The EU’s Artificial Intelligence Act(AI Act)imposes requirements for the privacy compliance of AI *** systems must comply with privacy laws such as the GDPR when providing *** laws provide users with the right to issue a Data Subject Access Request(DSAR).Responding to such requests requires database administrators to identify information related to an individual ***,manual compliance poses significant challenges and is *** administrators need to write queries through time-consuming *** demand for large amounts of data by AI systems has driven the development of NoSQL *** to the flexible schema of NoSQL databases,identifying personal information becomes even more *** paper develops an automated tool to identify personal information that can help organizations respond to *** tool employs a combination of various technologies,including schema extraction of NoSQL databases and relationship identification from query *** describe the algorithm used by our tool,detailing how it discovers and extracts implicit relationships from NoSQL databases and generates relationship graphs to help developers accurately identify personal *** evaluate our tool on three datasets,covering different database designs,achieving an F1 score of 0.77 to *** results demonstrate that our tool successfully identifies information relevant to the data *** tool reduces manual effort and simplifies GDPR compliance,showing practical application value in enhancing the privacy performance of NOSQL databases and AI systems.

关键词： GDPR compliance NoSQL databases AI system privacy

A Dual Domain Robust Reversible Watermarking Algorithm for Frame Grouping Videos Using Scene Smoothness

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Computers, Materials & Continua 2024年第6期79卷 5143-5174页

作者： Yucheng Liang Ke Niu Yingnan Zhang yifei Meng College of Cryptographic Engineering Engineering University of the Chinese People’s Armed Police ForceXi’an710086China Key Laboratory of Information Security of the Chinese People’s Armed Police Force Engineering University of the Chinese People’s Armed Police ForceXi’an710086China

The proposed robust reversible watermarking algorithm addresses the compatibility challenges between robustness and reversibility in existing video watermarking techniques by leveraging scene smoothness for frame grouping *** in the H.264.video coding standard,the algorithm first employs traditional robust watermark stitching technology to embed watermark information in the low-frequency coefficient domain of the U ***,it utilizes histogram migration techniques in the high-frequency coefficient domain of the U channel to embed auxiliary information,enabling successful watermark extraction and lossless recovery of the original video *** results demonstrate the algorithm’s strong imperceptibility,with each embedded frame in the experimental videos achieving a mean peak signal-to-noise ratio of 4..3830 dB and a mean structural similarity of *** with the three comparison algorithms,the performance of the two experimental indexes is improved by 7.59%and 0.4.on *** the same time,the proposed algorithm has strong robustness to both offline and online attacks:In the face of offline attacks,the average normalized correlation coefficient between the extracted watermark and the original watermark is 0.9989,and the average bit error rate is *** the face of online attacks,the normalized correlation coefficient between the extracted watermark and the original watermark is 0.884.,and the mean bit error rate is *** with the three comparison algorithms,the performance of the two experimental indexes is improved by 1.27%and 18.16%on average,highlighting the algorithm’s ***,the algorithm exhibits low computational complexity,with the mean encoding and the mean decoding time differentials during experimental video processing being 3.934.and 2.273 s,respectively,underscoring its practical utility.

关键词： Robust reversible watermarking scene smoothness dual-domain U channel H.264.encoding standard