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Article ; Online: Finite-Time Height Control of Quadrotor UAVs

Shuaihe Zhao / Yuanqing Xia / Liqun Ma / Hongjiu Yang

Applied Sciences, Vol 13, Iss 7914, p

2023 Volume 7914

Abstract: The quadrotor Unmanned Aerial Vehicle (UAV) belongs to an open-loop unstable nonlinear system, which also has the characteristics of underdrive, strong coupling and external disturbance. In the height control of quadrotor UAVs, the traditional sliding ... ...

Abstract	The quadrotor Unmanned Aerial Vehicle (UAV) belongs to an open-loop unstable nonlinear system, which also has the characteristics of underdrive, strong coupling and external disturbance. In the height control of quadrotor UAVs, the traditional sliding mode control (SMC) and PID methods cannot quickly and effectively eliminate disturbance effects caused by gust, aerodynamic drag and other factors, which indicates that the quadrotor UAV cannot return to its predetermined trajectory. To this end, this paper proposes a dual closed-loop finite-time height control method for the quadrotor UAV. The proposed method is able to estimate and compensate for the disturbance in the height control and make up for the lack of anti-disturbance ability in the control process. More specifically, a finite-time Extended State Observer (ESO) and a finite-time super-twisting controller are designed for the velocity control system to compensate for the total disturbance and track the rapidly changing expected signal. An integral sliding mode controller is designed for the height control system. Simulation results show that the proposed method can reduce the chattering phenomenon of traditional SMC and improve both control accuracy and convergence speed.
Keywords	quadrotor UAV ; extended state observer ; super-twisting controller ; integral sliding mode controller ; height control ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	629
Language	English
Publishing date	2023-07-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Risk factor analysis for adverse prognosis of the fetal ventricular septal defect (VSD).

Shan, Wang / Yuanqing, Xia / Jing, Zhu / Xi, Wu / Huifeng, Guo / Yi, Wu

BMC pregnancy and childbirth

2023 Volume 23, Issue 1, Page(s) 683

Abstract: Background: Ventricular septal defect (VSD) is the most common subtype of congenital heart disease. In the present study, we aimed to determine whether chromosome aberration was associated with the occurrence of VSD and evaluate the association of VSD ... ...

Abstract	Background: Ventricular septal defect (VSD) is the most common subtype of congenital heart disease. In the present study, we aimed to determine whether chromosome aberration was associated with the occurrence of VSD and evaluate the association of VSD size, location and chromosome aberration with adverse outcomes in the Chinese fetuses. Methods: Fetuses with VSD and comprehensive follow-up data were included and evaluated retrospectively. Medical records were used to collect epidemiological data and foetal outcomes. For VSD fetuses, conventional karyotype and microarray analysis were conducted. After adjusting confounding factors by using multivariable logistic regression analyses, the association between chromosome variations and VSD occurrence was explored. The association between defect size, location and chromosome aberrations and adverse foetal outcomes was also investigated. Results: Chromosome aberration was the risk factor for VSD occurrence, raising 6.5-fold chance of developing VSD. Chromosome aberration, peri-membranous site and large defect size of VSD were significant risk factors of adverse fetal outcome. Chromosome aberrations, including pathogenic copy number variations (CNVs) and variations of uncertain significance (VUS), were both risk factors, increasing the risk of the adverse fetal outcome by 55.9 times and 6.7 times, respectively. The peri-membranous site would increase 5.3-fold risk and defects larger than 5 mm would increase the 7.1-fold risk for poor fetal outcome. Conclusions: The current investigation revealed that chromosomal abnormalities, large defects, and the peri-membranous site were all risk factors for poor fetal outcomes. Our study also indicated that chromosome aberration was one of risk factors for the VSD occurrence.
MeSH term(s)	Humans ; DNA Copy Number Variations ; Retrospective Studies ; Risk Factors ; Fetus ; Heart Septal Defects, Ventricular/epidemiology ; Heart Septal Defects, Ventricular/genetics ; Prognosis ; Chromosome Aberrations ; Factor Analysis, Statistical
Language	English
Publishing date	2023-09-21
Publishing country	England
Document type	Journal Article
ZDB-ID	2059869-5
ISSN	1471-2393 ; 1471-2393
ISSN (online)	1471-2393
ISSN	1471-2393
DOI	10.1186/s12884-023-05969-9
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Article ; Online: Construction and Evaluation of Prediction Model of Main Soil Nutrients Based on Spectral Information

Siyao Yu / Haoran Bu / Wancheng Dong / Zhen Jiang / Lixin Zhang / Yuanqing Xia

Applied Sciences, Vol 12, Iss 6298, p

2022 Volume 6298

Abstract: The rapid and accurate detection of soil nutrient content through spectral technology is one of the requisite technologies for precision fertilization, which, however, is an unsolved issue. In order to achieve this purpose, a more robust and accurate ... ...

Abstract	The rapid and accurate detection of soil nutrient content through spectral technology is one of the requisite technologies for precision fertilization, which, however, is an unsolved issue. In order to achieve this purpose, a more robust and accurate model is established in this study. The regression algorithm is integrated with effective wavelength selection to construct the prediction model for total nitrogen, available phosphorus, and available potassium (N, P, and K), which removes the need for complex pretreatment and algorithm constraints. According to the research results, with regard to the prediction of soil nitrogen, phosphorus, and potassium contents, the joint interval support vector regression (Si-SVR) model performed best in modeling, with the root mean square error of prediction ( RMSEP ) limited to 0.0231%, 1.0554%, and 3.4225%, respectively. In addition, the relative percentage deviation ( RPD ) values were restricted to 2.68, 2.12, and 2.37, respectively. As indicated by the prediction results obtained for the above three nutrient contents, the RPD values of the Si-SVR model prediction accuracy evaluation indicators exceeded 2.0, which evidences a high level of prediction accuracy. This method makes it possible for spectral data to be applied in practical production, and these results provide a valuable reference for the effective detection of major soil nutrients.
Keywords	soil nutrient ; regression model ; hyperspectral ; N ; P ; K ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	550
Language	English
Publishing date	2022-06-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Calibration and Testing of Discrete Element Simulation Parameters for Urea Particles

Haoran Bu / Siyao Yu / Wancheng Dong / Yuqi Wang / Lixin Zhang / Yuanqing Xia

Processes, Vol 10, Iss 511, p

2022 Volume 511

Abstract: The lack of accurate simulation model parameters in the optimization design process of variable fertilizer application devices has resulted in large errors between simulation and theoretical calculation results, which has restricted the development of ... ...

Abstract	The lack of accurate simulation model parameters in the optimization design process of variable fertilizer application devices has resulted in large errors between simulation and theoretical calculation results, which has restricted the development of variable fertilizer application devices to a certain extent. Additionally, there are few scholars studying urea granules, so many parameters of urea granular fertilizer cannot be directly obtained from the literature. The aim of this study is to calibrate a set of simulation parameters by combining physical and simulation tests. In this study, intrinsic parameters were systematically determined, including the particle size, particle density, elastic modulus, Poisson’s ratio and their static friction coefficients, rolling friction coefficients and restitution coefficients of urea particles. By performing the urea particle stacking test, the static friction coefficient between urea particles was calibrated to 0.27, and the rolling friction coefficient between particles was 0.11. To check the reliability of the calibration parameters, the simulation and physical tests of the repose angle and bulk density of urea particles were compared, and the results show that the relative error of repose angles and bulk density of urea particles was 0.78% and 1.19%, respectively. Through the simulation of the mechanical variable fertilizer discharger and the comparison test of the benchtop fertilizer discharging performance, the maximum relative error between the simulation and physical test fertilizer discharge is 3.69% when the working length of the outer sheave is 25 mm; the maximum relative error between the simulation and physical test fertilizer discharge is 3.39% when the working length is 35 mm; the maximum relative error between the simulation and physical test fertilizer discharge is 6.86% when the working length is 45 mm; the maximum relative error between the simulation and physical test fertilizer discharge is 4.95% when the working length is 55 mm. The maximum ...
Keywords	urea particles ; discrete element ; test ; repose angle ; friction coefficient ; Chemical technology ; TP1-1185 ; Chemistry ; QD1-999
Subject code	600
Language	English
Publishing date	2022-03-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Networked Predictive Control for Nonlinear Systems With Arbitrary Region Quantizers.

Hongjiu Yang / Yang Xu / Yuanqing Xia / Jinhui Zhang

IEEE transactions on cybernetics

2017 Volume 47, Issue 8, Page(s) 2244–2255

Abstract: In this paper, networked predictive control is investigated for planar nonlinear systems with quantization by an extended state observer (ESO). The ESO is used not only to deal with nonlinear terms but also to generate predictive states for dealing with ... ...

Abstract	In this paper, networked predictive control is investigated for planar nonlinear systems with quantization by an extended state observer (ESO). The ESO is used not only to deal with nonlinear terms but also to generate predictive states for dealing with network-induced delays. Two arbitrary region quantizers are applied to take effective values of signals in forward channel and feedback channel, respectively. Based on a "zoom" strategy, sufficient conditions are given to guarantee stabilization of the closed-loop networked control system with quantization. A simulation example is proposed to exhibit advantages and availability of the results.
Language	English
Publishing date	2017-04-06
Publishing country	United States
Document type	Journal Article
ISSN	2168-2275
ISSN (online)	2168-2275
DOI	10.1109/TCYB.2017.2689030
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Article ; Online: An Extreme Learning Machine-Based Community Detection Algorithm in Complex Networks

Feifan Wang / Baihai Zhang / Senchun Chai / Yuanqing Xia

Complexity, Vol

2018 Volume 2018

Abstract: Community structure, one of the most popular properties in complex networks, has long been a cornerstone in the advance of various scientific branches. Over the past few years, a number of tools have been used in the development of community detection ... ...

Abstract	Community structure, one of the most popular properties in complex networks, has long been a cornerstone in the advance of various scientific branches. Over the past few years, a number of tools have been used in the development of community detection algorithms. In this paper, by means of fusing unsupervised extreme learning machines and the k-means clustering techniques, we propose a novel community detection method that surpasses traditional k-means approaches in terms of precision and stability while adding very few extra computational costs. Furthermore, results of extensive experiments undertaken on computer-generated networks and real-world datasets illustrate acceptable performances of the introduced algorithm in comparison with other typical community detection algorithms.
Keywords	Electronic computers. Computer science ; QA75.5-76.95
Language	English
Publishing date	2018-01-01T00:00:00Z
Publisher	Hindawi-Wiley
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Trends of central obesity and associations with nutrients intake and daily behaviors among women of childbearing age in China

Zichong Long / Lili Huang / Jiajun Lyu / Yuanqing Xia / Yiting Chen / Rong Li / Yanlin Wang / Shenghui Li

BMC Women's Health, Vol 22, Iss 1, Pp 1-

2022 Volume 11

Abstract: Abstract Background Obesity among women of childbearing age has becoming an important public health concern. We aimed to describe the trends of central obesity among Chinese women of childbearing age from 2004 to 2011 and to examine its associations with ...

Abstract	Abstract Background Obesity among women of childbearing age has becoming an important public health concern. We aimed to describe the trends of central obesity among Chinese women of childbearing age from 2004 to 2011 and to examine its associations with nutrients intake and daily behaviors. Methods Longitudinal data were derived from the China Health and Nutrition Survey. Participants consisted of 2481 women aged 15–44 years old. WC (Waist circumference) and WHtR (Waist to height ratio) were adopted as indicators of central obesity. Generalized linear mixed model was performed to analyze the associations of nutrients intake and daily behaviors with central obesity. Results From 2004 to 2011, the prevalence of central obesity among Chinese women of childbearing age increased from 21.6 to 30.7% (WC as indice) or from 22.8 to 32.6% (WHtR as indice) (both p < 0.001). Protein intake above the AMDR (Acceptable macronutrient distribution range) (OR = 1.21, 95% CI 1.05–1.39, p < 0.01) and non-participation in LTPA (Leisure time physical activity) (OR = 1.45, 95% CI 1.17–1.80, p < 0.001) were risk factors for high WC, and the latter was also associated with high WHtR (OR = 1.36, 95% CI 1.10–1.67, p < 0.01). For those women who had high WC & high WHtR, the impacts of protein intake and LTPA became stronger, especial LTPA (OR = 1.53, 95% CI 1.21–1.94, p < 0.001). Age-stratified analyses found that non-participation in LTPA was key factor for central obesity in 15–34 age group, while protein intake above the AMDR was pronounced in the 35–44 age group. Conclusions Non-participation in LTPA and protein intake above the AMDR were significant contributors of central obesity, which could be intervention targets to deal with the growing trend of central obesity among women of childbearing age.
Keywords	Women of childbearing age ; Central obesity ; Physical activity ; Nutrients ; Gynecology and obstetrics ; RG1-991 ; Public aspects of medicine ; RA1-1270
Subject code	610
Language	English
Publishing date	2022-01-01T00:00:00Z
Publisher	BMC
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Fault Detection for T-S Fuzzy Discrete Systems in Finite-Frequency Domain.

Hongjiu Yang / Yuanqing Xia / Bo Liu

IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics : a publication of the IEEE Systems, Man, and Cybernetics Society

2011 Volume 41, Issue 4, Page(s) 911–920

Abstract: This paper investigates the problem of fault detection for Takagi-Sugeno (T-S) fuzzy discrete systems in finite-frequency domain. By means of the T-S fuzzy model, both a fuzzy fault detection filter system and the dynamics of filtering error generator ... ...

Abstract	This paper investigates the problem of fault detection for Takagi-Sugeno (T-S) fuzzy discrete systems in finite-frequency domain. By means of the T-S fuzzy model, both a fuzzy fault detection filter system and the dynamics of filtering error generator are constructed. Two finite-frequency performance indices are introduced to measure fault sensitivity and disturbance robustness. Faults are considered in a middle frequency domain, while disturbances are considered in another certain finite-frequency domain interval. By using the generalized Kalman-Yakubovic-Popov Lemma in a local linear system model, the design methods are presented in terms of solutions to a set of linear matrix inequalities, which can be readily solved via standard numerical software. The design problem is formulated as a two-objective optimization algorithm. A numerical example is given to illustrate the effectiveness and potential of the developed techniques.
Language	English
Publishing date	2011-08
Publishing country	United States
Document type	Journal Article
ISSN	1083-4419
ISSN	1083-4419
DOI	10.1109/TSMCB.2010.2099653
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Article ; Online: Unscented Particle Filtering for Estimation of Shipboard Deformation Based on Inertial Measurement Units

Bo Wang / Xuan Xiao / Yuanqing Xia / Mengyin Fu

Sensors, Vol 13, Iss 11, Pp 15656-

2013 Volume 15672

Abstract: Shipboard is not an absolute rigid body. Many factors could cause deformations which lead to large errors of mounted devices, especially for the navigation systems. Such errors should be estimated and compensated effectively, or they will severely reduce ...

Abstract	Shipboard is not an absolute rigid body. Many factors could cause deformations which lead to large errors of mounted devices, especially for the navigation systems. Such errors should be estimated and compensated effectively, or they will severely reduce the navigation accuracy of the ship. In order to estimate the deformation, an unscented particle filter method for estimation of shipboard deformation based on an inertial measurement unit is presented. In this method, a nonlinear shipboard deformation model is built. Simulations demonstrated the accuracy reduction due to deformation. Then an attitude plus angular rate match mode is proposed as a frame to estimate the shipboard deformation using inertial measurement units. In this frame, for the nonlinearity of the system model, an unscented particle filter method is proposed to estimate and compensate the deformation angles. Simulations show that the proposed method gives accurate and rapid deformation estimations, which can increase navigation accuracy after compensation of deformation.
Keywords	shipboard deformation ; inertial measurement unit ; unscented particle filter ; attitude plus angular rate match mode ; Technology (General) ; T1-995 ; Technology ; T ; DOAJ:Technology (General) ; DOAJ:Technology and Engineering ; Analytical chemistry ; QD71-142 ; Chemistry ; QD1-999 ; Science ; Q ; DOAJ:Analytical Chemistry ; DOAJ:Chemistry
Subject code	620
Language	English
Publishing date	2013-11-01T00:00:00Z
Publisher	Multidisciplinary Digital Publishing Institute
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: How to Understand “Herd Immunity” in COVID-19 Pandemic

Yuanqing Xia / Lumin Zhong / Jingcong Tan / Zhiruo Zhang / Jiajun Lyu / Yiting Chen / Anda Zhao / Lili Huang / Zichong Long / Ning-Ning Liu / Hui Wang / Shenghui Li

Frontiers in Cell and Developmental Biology, Vol

2020 Volume 8

Abstract: The COVID-19 pandemic has been a global threat. Through rapid and effective surveillance and control, the newly confirmed patients have been fluctuated at a very low level and imported case explained most of them through March, 2020 to the present, ... ...

Abstract	The COVID-19 pandemic has been a global threat. Through rapid and effective surveillance and control, the newly confirmed patients have been fluctuated at a very low level and imported case explained most of them through March, 2020 to the present, indicating China’s response has achieved a stage victory. By contrast, the epidemic of COVID-19 in other countries out of China is bursting. Different countries are adopting varied response strategy in terms of their public health system to prevent the spread. Herd immunity has been a hot topic since the outbreak of COVID-19 pandemic. Can it be a possible strategy to combat COVID-19? To fully interpret the knowledge regarding the term upon the background of COVID-19-related health crisis, we aim to systematically review the definition, describe the effective measures of acquiring herd immunity, and discuss its feasibility in COVID-19 prevention. Findings from this review would promote and strengthen the international cooperation and joint efforts when confronting with COVID-19.
Keywords	COVID-19 ; SARS-CoV-2 ; herd immunity ; outbreak ; pandemic ; Biology (General) ; QH301-705.5 ; covid19
Language	English
Publishing date	2020-09-01T00:00:00Z
Publisher	Frontiers Media S.A.
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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