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Dynamic flight stability of a model dronefly in vertical flight

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Acta Mechanica Sinica 2014年第6期30卷 828-838页

作者： chong shen Mao Sun Institute of Fluid Mechanics Beijing University of Aeronautics & Astronautics

The dynamic flight stability of a model dronefly in hovering and upward flight is *** method of computational fluid dynamics is used to compute the stability derivatives and the techniques of eigenvalue and eigenvector used to solve the equations of *** major finding is as *** flight of the model dronefly is unstable because of the existence of an unstable longitudinal and an unstable lateral natural mode of *** flight of the insect is also unstable,and the instability increases as the upward flight speed *** force generated by the upward flight velocity coupled with the disturbance in pitching angular velocity is responsible for the enhancement of the instability.

关键词： Insect vertical flight Flight stability Natural modes of motion

Reinforcement learning models for scheduling in wireless networks

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Frontiers of Computer Science 2013年第5期7卷 754-766页

作者： Kok-Lim Alvin YAU Kae Hsiang KWONG chong shen Faculty of Science and Technology Sunway University Selangor 46150 Malaysia R&D Department Recovision Selangor 47650 Malaysia College of Information Science and Technology Hainan University Haikou 570228 China

The dynamicity of available resources and net- work conditions, such as channel capacity and traffic charac- teristics, have posed major challenges to scheduling in wire- less networks. Reinforcement learning （RL） enables wire- less nodes to observe their respective operating environment, learn, and make optimal or near-optimal scheduling deci- sions. Learning, which is the main intrinsic characteristic of RL, enables wireless nodes to adapt to most forms of dynamicity in the operating environment as time goes by. This paper presents an extensive review on the application of the traditional and enhanced RL approaches to various types of scheduling schemes, namely packet, sleep-wake and task schedulers, in wireless networks, as well as the advantages and performance enhancements brought about by RL. Addi- tionally, it presents how various challenges associated with scheduling schemes have been approached using RL. Finally, we discuss various open issues related to RL-based schedul- ing schemes in wireless networks in order to explore new re- search directions in this area. Discussions in this paper are presented in a tutorial manner in order to establish a founda- tion for further research in this field.

关键词： reinforcement learning scheduling wireless networks

Observer-Based Adaptive Robust Precision Motion Control of a Multi-Joint Hydraulic Manipulator

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1213-1226页

作者： Zheng Chen Shizhao Zhou chong shen Litong Lyu Junhui Zhang Bin Yao State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027 Ocean College Zhejiang UniversityZhoushan 316021China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050000 State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China School of Mechanical Engineering Purdue UniversityWest LafayetteIN 47907 USA

Hydraulic manipulators are usually applied in heavy-load and harsh operation ***,when faced with a complex operation,the traditional proportional-integral-derivative(PID)control may not meet requirements for high control ***-based full-state-feedback control is an effective alternative,but the states of a hydraulic manipulator are not always available and reliable in practical applications,particularly the joint angular velocity *** that it is not suitable to obtain the velocity signal directly from differentiating of position measurement,the low-pass filtering is commonly used,but it will definitely restrict the closed-loop bandwidth of the whole *** avoid this problem and realize better control performance,this paper proposes a novel observerbased adaptive robust controller(obARC)for a multi-joint hydraulic manipulator subjected to both parametric uncertainties and the lack of accurate velocity ***,a nonlinear adaptive observer is first designed to handle the lack of velocity measurement with the consideration of parametric ***,the adaptive robust control is developed to compensate for the dynamic uncertainties,and the close-loop system robust stability is theoretically proved under the observation and control ***,comparative experiments are carried out to show that the designed controller can achieve a performance improvement over the traditional methods,specifically yielding better control accuracy owing to the closed-loop bandwidth breakthrough,which is limited by low-pass filtering in fullstate-feedback control.

关键词： handle Observer filtering

A multiscale transform denoising method of the bionic polarized light compass for improving the unmanned aerial vehicle navigation accuracy

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Chinese Journal of Aeronautics 2022年第4期35卷 400-414页

作者： Donghua ZHAO Jun TANG Xindong WU Jing ZHAO Chenguang WANG chong shen Jun LIU Key Laboratory of Instrumentation Science&Dynamic Measurement Ministry of EducationSchool of Instrument and ElectronicsNorth University of ChinaTaiyuan 03005JPR China School of Information and Communication Engineering North University of ChinaTaiyuan 030051PR China

In recent years, the bionic polarized light compass has been widely studied for the unmanned aerial vehicle navigation. However, it is found from the obtained investigation results that a polarized light compass with a sensitive and high dynamic range polarimeter still provides inferior output precision of the heading angle due to the presence of the noise generating from the *** noise is existed not only in the angle of the polarization image acquired by polarimeters but also in the output heading data, which leads to a sharp reduction in the accuracy of a polarized light compass. Herein, we present noise analysis and a novel multiscale transform denoising method of a polarized light compass used for the unmanned aerial vehicle navigation. Specifically, a multiscale principle component analysis utilizing one-dimensional image entropy as classification criterion is directly implemented to suppress the noise in the acquired polarization image. Subsequently, a multiscale time–frequency peak filtering method using the sample entropy as classification criterion is applied for the output heading data so as to further increase the heading measurement accuracy from the denoised image above. These two approaches are combined to significantly reduce the heading error affected by different types of noises. Our experimental results indicate the proposed multiscale transform denoising method exhibits high performance in suppressing the noise of a polarized light compass used for the unmanned aerial vehicle navigation compared to existing prior arts.

关键词： Denoising Multi-scale transform Orientation Polarized light compass UAV navigation

Influence of Superplasticizers on Early Age Drying Shrinkage of Cement Paste with the Same Consistency

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Journal of Wuhan University of Technology(Materials Science) 2014年第6期29卷 1201-1207页

作者：赖俊英 ZHANG Lifeng 钱晓倩 shen chong ZHANG Jinjian College of Civil Engineering and Architecture Zhejiang University

The influence of superplasticizer（SP） on the early age drying shrinkage of cement paste with the same consistency was investigated. To conduct the test, which lasted for 72 hours, three paste mixtures were used for comparison. The 72 hours early age drying shrinkage staring from the initial setting time was measured by a clock gauge. The pore size distribution was measured by Mercury Intrusion Method. The surface tension of capillary simulation liquid and mass loss of paste were also measured. The experimental results showed that the addition of SP increased the early drying shrinkage greatly. The ratios of water evaporation and the total free water in mixtures added with SPs showed great differences. SPs fined the capillary pores of paste, and the volume of pore with diameter within 50 nm was well consistent with shrinkage rate. The addition of SPs did not raise the capillary liquid surface tension. It showed that with the volume of pore with diameter within 50 nm and the ratio of water evaporation and the total free water a tolerable shrinkage result of paste added with SP could be predicted, and the elastic modulus could have an influence on the early shrinkage. These results have never been proposed before.

关键词： superplasticizer early age drying shrinkage paste water evaporation pore size distribution

Reliable attitude estimation algorithm considering atypical observation

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Science China(Information Sciences) 2022年第10期65卷 301-302页

作者： Xiao-Ting GUO chong shen Jun TANG Jie LI Jun LIU Key Laboratory of Instrumentation Science and Dynamic Measurement Ministry of Education School of Instrument and Electronics North University of China

Dear editor,Attitude estimation has theoretical significance and engineering application value in tracking, control, navigation and positioning [1] in the military and civil domain. Common single attitude measurement techniques based on inertial techniques [2] or monocular vision are defective in trying to meet multiple measurement requirements as their own inherent features.

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Inhibition of proliferation,migration,and invasiveness of bladder cancer cells through SAPCD2 knockdown

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BIOCELL 2024年第1期48卷 97-109页

作者： chong shen JIAJUN YAN YU REN ZHIRONG ZHU XIAOLONG ZHANG SHUIXIANG TAO Department of Urology Shaoxing People’s HospitalShaoxing HospitalZhejiang University School of MedicineShaoxingChina

Introduction:Bladder cancer(BC)has a high incidence and mortality rate *** anaphasepromoting complex domain containing 2(SAPCDC2)is over-expressed in a variety of ***:This study investigated the effects of SAPCD2 knockdown on BC ***:T24 and UMUC3 cell models and the xenografted BC tumor model with SAPCD2 knockdown were established to observe the malignant phenotype of BC cells by cell counting kit-8 assay,colony formation test,wound healing,and Transwell assay,mRNA and proteins expressions were measured with quantitative real-time polymerase chain reaction,western blotting,and tissue *** chloride agonist on the Wnt/β-catenin pathway was used to clarify the molecular mechanism of SAPCD2 ***:SAPCD2 expression was significantly higher in BC cell lines than in SVHUC-1 ***2 knockdown inhibited viability and cloning,hindered the G0/G1 phase of the cell cycle in UMUC3 and T24 cells,and decreased the migration and invasiveness of BC ***2 knockdown inhibited expression levels of cyclin D1,cyclin B1,N-cadherin,vimentin,Snail,β-catenin,c-Myc,and cyclin-dependent kinase 4,while the P21 and E-cadherin were raised by SAPCD2 ***,lithium chloride reversed the effects of SAPCD2 knockdown on the expression levels of the above proteins in UMUC3 and T24 *** vivo,SAPCD2 knockdown inhibited the volume,weight,and expression of Ki-67 andβ-catenin in tumors and increased the E-cadherin ***:SAPCD2 knockdown inhibits the malignant phenotype of BC via a pathway involvingβ-catenin.

关键词： Bladder cancer SAPCD2 β-catenin c-Myc CDK4 Lithium chloride

Spatial Interpolation of Soil Texture Using Compositional Kriging and Regression Kriging with Consideration of the Characteristics of Compositional Data and Environment Variables

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Journal of Integrative Agriculture 2013年第9期12卷 1673-1683页

作者： ZHANG Shi-wen shen chong-yang CHEN Xiao-yang YE Hui-chun HUANG Yuan-fang LAI Shuang China Agricultural University/Key Laboratory of Arable Land Conservation (North China) Minstry of Agriculture/Key Laboratory of Agricultural Land Quality MonitoringMinistry of Land and Resources School of Earth and Environment Anhui University of Science and Technology Afforestation Management Office Sichuan Forestry Department

The spatial interpolation for soil texture does not necessarily satisfy the constant sum and nonnegativity constraints. Meanwhile, although numeric and categorical variables have been used as auxiliary variables to improve prediction accuracy of soil attributes such as soil organic matter, they （especially the categorical variables） are rarely used in spatial prediction of soil texture. The objective of our study was to comparing the performance of the methods for spatial prediction of soil texture with consideration of the characteristics of compositional data and auxiliary variables. These methods include the ordinary kriging with the symmetry logratio transform, regression kriging with the symmetry logratio transform, and compositional kriging （CK） approaches. The root mean squared error （RMSE）, the relative improvement value of RMSE and Aitchison＇s distance （DA） were all utilized to assess the accuracy of prediction and the mean squared deviation ratio was used to evaluate the goodness of fit of the theoretical estimate of error. The results showed that the prediction methods utilized in this paper could enable interpolation results of soil texture to satisfy the constant sum and nonnegativity constraints. Prediction accuracy and model fitting effect of the CK approach were better, suggesting that the CK method was more appropriate for predicting soil texture. The CK method is directly interpolated on soil texture, which ensures that it is optimal unbiased estimator. If the environment variables are appropriately selected as auxiliary variables, spatial variability of soil texture can be predicted reasonably and accordingly the predicted results will be satisfied.

关键词： compositional kriging auxiliary variables regression kriging symmetry logratio transform

Association of PPARγand AGTR1 Polymorphisms with Hypertriglyceridemia in Chinese Population

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Biomedical and Environmental Sciences 2018年第8期31卷 619-622页

作者： DING Yi GUO Dao Xia JING Yang WANG Jie shen chong KHOU Hui DONG Chen Department of Epidemiology and Statistics School of Public HealthJiangsu Key Laboratory and Translational Medicine for Geriatric DiseaseMedical College of Soochow UniversitySuzhou 215123JiangsuChina Suzhou IndustrialPark Centers for Disease Control and Prevention Suzhou 215021JiangsuChina Department of Epidemiology andStatistics School of Public HealthNanjing Medical UniversityNanjing 211166JiangsuChina

Hypertriglyceridemia （HTG） is an important metabolic disease and strongly associated with the development of hypertension, atherosclerosis,coronary artery disease, and type 2 diabetes mellitus（T2DM）. HTG risk is affected by various factors and might occur owing to the complex synergistic interaction between the genetic background and environmental factors;.

关键词： Association of PPAR HTG and AGTR1 Polymorphisms with Hypertriglyceridemia in Chinese Population