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Extremum seeking control for UAV close formation flight via improved pigeon-inspired optimization

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Science China(Technological Sciences) 2024年第2期67卷 435-448页

作者： YUAN GuangSong duan HaiBin State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical EngineeringBeihang University(BUAA)Beijing 100083China

This paper proposes a comprehensive design scheme for the extremum seeking control(ESC)of the unmanned aerial vehicle(UAV)close formation *** proposed design scheme combines a Newton-Raphson method with an extended Kalman filter(EKF)to dynamically estimate the optimal position of the following UAV relative to the leading *** reflect the wake vortex effects reliably,the drag coefficient induced by the wake vortex is considered as a performance ***,the performance function is parameterized by the first-order and second-order terms of its Taylor series *** the excellent performance of nonlinear estimation,the EKF is used to estimate the gradient and the Hessian matrix of the parameterized performance *** output feedback of the proposed scheme is determined by iterative calculation of the Newton-Raphson *** with the traditional ESC and the classic ESC,the proposed design scheme avoids the slow continuous time integration of the *** allows a faster convergence of relative position ***,the proposed method can provide a smoother command during the seeking process as the second-order term of the performance function is taken into *** convergence analysis of the proposed design scheme is accomplished by showing that the output feedback is a supermartingale *** improve estimation performance of the EKF,a improved pigeon-inspired optimization(IPIO)is proposed to automatically tune the noise covariance *** Carlo simulations for a three-UAV close formation show that the proposed design scheme is robust to the initial position of the following UAV.

关键词： unmanned aerial vehicle close formation extremum seeking control Newton-Raphson method improved pigeon-inspired optimization

Noninvasive Diagnostic Technique for Nonalcoholic Fatty Liver Disease Based on Features of Tongue Images

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Chinese Journal of Integrative Medicine 2024年第3期30卷 203-212页

作者： WANG Rong-rui CHEN Jia-liang duan Shao-jie LU ying-xi CHEN Ping ZHOU Yuan-chen YAO Shu-kun Graduate School of Beijing University of Chinese Medicine Beijing100029China Department of Gastroenterology China-Japan Friendship HospitalBeijing100029China Center of Integrative Medicine Beijing Ditan HospitalCapital Medical UniversityBeijing100015China nanjing Linkwah Micro-electronics Institute Beijing100191China Institute of Microelectronics Tsinghua UniversityBeijing100084China Peking University China-Japan Friendship School of Clinical Medicine Beijing100029China

Objective:To investigate a new noninvasive diagnostic model for nonalcoholic fatty liver disease(NAFLD) based on features of tongue ***:Healthy controls and volunteers confirmed to have NAFLD by liver ultrasound were recruited from China-Japan Friendship Hospital between September 2018 and May 2019,then the anthropometric indexes and sampled tongue images were *** tongue images were labeled by features,based on a brief protocol,without knowing any other clinical data,after a series of corrections and data *** algorithm was trained on images using labels and several anthropometric indexes for inputs,utilizing machine learning ***,a logistic regression algorithm and a decision tree model were constructed as 2 diagnostic models for ***:A total of 720 subjects were enrolled in this study,including 432 patients with NAFLD and 288 healthy *** them,482 were randomly allocated into the training set and 238 into the validation *** diagnostic model based on logistic regression exhibited excellent performance:in validation set,it achieved an accuracy of 86.98%,sensitivity of 91.43%,and specificity of 80.61%;with an area under the curve(AUC) of 0.93 [95% confidence interval(CI) 0.68–0.98].The decision tree model achieved an accuracy of 81.09%,sensitivity of 91.43%,and specificity of 66.33%;with an AUC of 0.89(95% CI 0.66–0.92) in validation ***:The features of tongue images were associated with *** the 2 diagnostic models,which would be convenient,noninvasive,lightweight,rapid,and inexpensive technical references for early screening,can accurately distinguish NAFLD and are worth further study.

关键词： nonalcoholic fatty liver disease noninvasive diagnosis tongue image tongue diagnosis Chinese medicine machine learning

Effects of transient flow conditions on colloid-facilitated release of decabromodiphenyl ether:Implications for contaminant mobility at e-waste recycling sites

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Eco-Environment & Health 2024年第3期3卷 317-324页

作者： Yueyue Li Zebin Huo Yuqin ying Lin duan Chuanjia Jiang Wei Chen College of Environmental Science and Engineering Ministry of Education Key Laboratory of Pollution Processes and Environmental CriteriaTianjin Key Laboratory of Environmental Remediation and Pollution ControlNankai UniversityTianjin 300350China

Polybrominated diphenyl ethers(PBDEs)are ubiquitous contaminants,especially in the soil and groundwater of contaminated sites and ***,2,20,3,30,4,40,5,50,6,60-decabromodiphenyl ether(BDE-209),one of the most frequently and abundantly detected PBDE congeners in the environment,has recently been designated as a new pollutant subject to rigorous control in ***-facilitated transport is a key mechanism for the release of PBDEs from surface soils and their migration in the aquifer,but the effects of hydrodynamic conditions,particularly transient flow,on colloid-facilitated release of PBDEs are not well ***,we examined the effects of typical transient flow conditions on the release characteristics of colloids and BDE-209 from surface soil collected from an e-waste recycling site by undisturbed soil core leaching tests involving multiple dry–wet cycles(with different drying durations)and freeze–thaw *** observed significant positive correlations between BDE-209 and colloid concentrations in the leachate in both the dry–wet and freeze–thaw leaching experiments,highlighting the critical role of colloids in facilitating BDE-209 ***,colloids mobilized during the dry–wet cycles contained higher contents of BDE-209 than those in the freeze–thaw cycle tests,and the difference was primarily due to the more intensive disintegration of soil aggregates and elution of newly formed inorganic colloidal particles(mainly primary silicate minerals such as quartz and albite)with low BDE-209 content during the freeze–thaw *** findings underscore the necessity of considering transient flow conditions when assessing the fate and risks of PBDEs at contaminated sites.

关键词： Hydrophobic organic contaminants Colloid-facilitated transport Dry-wet cycle Freeze-thaw cycle Undisturbed soil core

Wide-color-gamut, high-purity, and high-brightness thin film structural colors based on modified Fano resonant structure

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Chinese Optics Letters 2024年第8期22卷 113-118页

作者： Weijie Chen Zexiang He Zhenzhen duan Jian Yang Ning Wang Dan Wang Zexiong Hu nan Chen Zhengqian Luo Yikun Bu School of Electronic Science and Engineering Xiamen UniversityXiamen 361005China Fujian Key Laboratory of Ultrafast Laser Technology and Applications Xiamen UniversityXiamen 361005China

Recently, the Fano resonance has played an increasingly important role in improving the color performance of structural colors. In this study, we further elucidate the asymmetric spectral shape generated by Fano resonance from a phase perspective and explore four distinct continuum state structures. By integrating the proposed cavity-like structure with a metal±dielectric±metal discrete state, multilayered thin-film structural colors with minimal background reflection, as low as 8%, were successfully achieved. The reflection peak of this structure exhibits a bandwidth of approximately50 nm and reaches up to 80%, indicating heightened saturation and color brightness. Moreover, by adjusting the thickness,we effortlessly obtained a broader color gamut compared to Adobe RGB (45.2%), covering 56.7% of the CIE color space. Even adjusting a single layer can achieve a color gamut of 47.1%. In experiments, by deliberately choosing low oxygendependent materials, excellent RGB colors with high brightness and in high consistency with simulation results were successfully achieved. Therefore, the scheme's simple process for structural color creation, along with its excellent color performance and the ability to effectively replicate simulation characteristics makes it highly valuable in fields like anticounterfeiting, decoration, display devices, and solar cell panels.

关键词： Fano resonance structural colors full color thin films high saturation

Drogue detection for autonomous aerial refueling via hybrid pigeon-inspired optimized color opponent and saliency aggregation

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Chinese Journal of Aeronautics 2024年第5期37卷 27-38页

作者： Tongyan WU Haibin duan Yanming FAN State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical EngineeringBeihang UniversityBeijing 100083China Virtual Reality Fundamental Research Laboratory Department of Mathematics and TheoriesPeng Cheng LaboratoryShenzhen 518000China AVIC Shenyang Aircraft Design and Research Institute Shenyang 110035China

Drogue detection is one of the challenging tasks in autonomous aerial refueling due to the requirement for accuracy and *** detection based on image intrinsic cues can achieve fast detection,but with poor *** studies reveal that optimization-based methods provide accurate and quick solutions for saliency *** paper presents a hybrid pigeon-inspired optimization method,the optimized color opponent,that aims to adjust the weight of color opponent channels to detect the drogue *** can optimize the weights in the selected aerial refueling scene offline,and the results are applied for drogue detection in the scene.A novel algorithm aggregated by the optimized color opponent and robust background detection is presented to provide better precision and *** results on benchmark datasets and aerial refueling images show that the proposed method successfully extracts the saliency region or drogue and exhibits superior performance against the other saliency detection methods with intrinsic *** algorithm designed in this paper is competent for the drogue detection task of autonomous aerial refueling.

关键词： Autonomous aerial refueling Drones Hybrid pigeon-inspired optimization Color opponent Saliency detection Saliency aggregation

Design Optimization and Operating Performance of S-CO_(2) Brayton Cycle under Fluctuating Ambient Temperature and Diverse Power Demand Scenarios

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Journal of Thermal Science 2024年第1期33卷 190-206页

作者： YANG Jingze YANG Zhen duan Yuanyuan Key Laboratory for Thermal Science and Power Engineering of MOE Beijing Key Laboratory for CO_(2) Utilization and Reduction TechnologyTsinghua UniversityBeijing 100084China

The supercritical CO_(2)(S-CO_(2)) Brayton cycle is expected to replace steam cycle in the application of solar power tower system due to the attractive potential to improve efficiency and reduce *** the concentrated solar power plant with thermal energy storage is usually located in drought area and used to provide a dispatchable power output,the S-CO_(2) Brayton cycle has to operate under fluctuating ambient temperature and diverse power demand *** addition,the cycle design condition will directly affect the off-design *** this work,the combined effects of design condition,and distributions of ambient temperature and power demand on the cycle operating performance are analyzed,and the off-design performance maps are proposed for the first time.A cycle design method with feedback mechanism of operating performance under varied ambient temperature and power demand is introduced *** show that the low design value of compressor inlet temperature is not conductive to efficient operation under low loads and sufficient output under high ambient *** average yearly efficiency is most affected by the average power demand,while the load cover factor is significantly influenced by the average ambient *** multi-objective optimization,the optimal solution of designed compressor inlet temperature is close to the minimum value of35℃ in Delingha with low ambient temperature,while reaches 44.15℃ in Daggett under the scenario of high ambient temperature,low average power demand,long duration and large value of peak load during the peak temperature *** the cycle designed with compressor inlet temperature of 35℃ instead of 44.15℃ in Daggett under light industry power demand,the reduction of load cover factor will reach 0.027,but the average yearly efficiency can barely be improved.

关键词： supercritical CO_(2)Brayton cycle ambient temperature fluctuating power demand scenarios design optimization off-design performance

Prescribed Performance Evolution Control for Quadrotor Autonomous Shipboard Landing

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1151-1162页

作者： Yang Yuan Haibin duan Zhigang Zeng State Key Laboratory of Virtual Reality Technology and Systems the School of Automation Science and Electrical EngineeringBeihang UniversityBeijing 100083China State Key Laboratory of Virtual Reality Technology and Systems the School of Automation Science and Electrical EngineeringBeihang UniversityBeijing 100083 Virtual Reality Fundamental Research Laboratory Department of Mathematics and TheoriesPeng Cheng LaboratoryShenzhen 518000China School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074China

The shipboard landing problem for a quadrotor is addressed in this paper,where the ship trajectory tracking control issue is transformed into a stabilization control issue by building a relative position *** guarantee both transient performance and steady-state landing error,a prescribed performance evolution control(PPEC)method is developed for the relative position *** addition,a novel compensation system is proposed to expand the performance boundaries when the input saturation occurs and the error exceeds the predefined *** the wind and wave on the relative position model,an adaptive sliding mode observer(ASMO)is designed for the disturbance with unknown upper *** on the dynamic surface control framework,a shipboard landing controller integrating PPEC and ASMO is established for the quadrotor,and the relative position control error is guaranteed to be uniformly ultimately *** results have verified the feasibility and effectiveness of the proposed shipboard landing control scheme.

关键词： error integrating stabilization

Exclusive Hypothesis Testing for Cox's Proportional Hazards Model

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Journal of Systems Science & Complexity 2024年第5期37卷 2157-2172页

作者： WU Qiang TONG Xingwei duan Xiaogang School of Statistics Beijing Normal University

Exclusive hypothesis testing is a new and special class of hypothesis testing. This kind of testing can be applied in survival analysis to understand the association between genomics information and clinical information about the survival time. Besides, it is well known that Cox's proportional hazards model is the most commonly used model for regression analysis of failure time. In this paper,the authors consider doing the exclusive hypothesis testing for Cox's proportional hazards model with right-censored data. The authors propose the comprehensive test statistics to make decision, and show that the corresponding decision rule can control the asymptotic Type Ⅰ errors and have good powers in theory. The numerical studies indicate that the proposed approach works well for practical situations and it is applied to a set of real data arising from Rotterdam Breast Cancer Data study that motivated this study.

关键词： Comprehensive test statistics Cox’s proportional hazards model exclusive hypothesis testing right-censored data Type I error

Measuring Financial Systemic Risk:Net Liability Clearing Mechanism and Contagion Effect

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Journal of Systems Science & Complexity 2024年第3期37卷 1114-1146页

作者： MA Jiali ZHU Shushang LI duan College of Big Data Statistics Guizhou University of Finance and EconomicsGuiyang 550025China School of Business Sun Yat-Sen UniversityGuangzhou 510275China School of Data Science City University of Hong KongHong Kong 999077China

Following the framework of E-N model(Eisenberg and Noe,2001),the authors consider a new clearing mechanism based on net liabilities among financial institutions since the liabilities between the counterparties should be deducted accordingly when clearing in *** the basis for systemic risk measurement,similar to the original E-N model,the authors first establish some good properties for the clearing payment vector according to a more general ***,the authors investigate how risk spreads among institutions through the liability network forming the risk contagion ***,the authors illustrate with a specific example that the original E-N clearing mechanism may misidentify the systemic important institutions,and theoretically show that it may also overestimate the risk compared with the netting clearing mechanism.

关键词： Clearing mechanism contagion net liability network systemic risk