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Chinese Journal of Electronics 2024年第2期33卷 504-515页

作者： Wei-Chiang wu College of Mechanical and Electrical Engineering Sanming University

This paper considers downlink multiuser multiple-input-multiple-output system with parallel spatial modulation scheme, in which base station transmitter antennas are separated into K groups corresponding to K user terminals. Generalized spatial modulation is employed, in which a subset(more than single antenna) of transmit antenna array are activated and the activating pattern corresponds to specific spatial symbol. Different from existing precoding-based algorithms, we develop a two-stage detection scheme at each user terminal: In the pre-processing stage, a minimax algorithm is proposed to identify the indices of active antennas, where the key idea is that the minimum output energy of the detector is maximized; A constrained minimum output energy algorithm is proposed in the post-processing stage to mitigate multiuser interference and extract temporal symbols. Compared with existing precoding-based algorithms, the complexity is significantly reduced. Moreover, the proposed algorithm is semi-blind,in which only a small subset of channel state information is required to identify active antennas as well as eliminate multiuser interference. Simulation results demonstrate that the proposed algorithm is near-far resistant and the spectral efficiency is extensively increased compared to the conventional spatial modulation scheme.

关键词： GSM Spectral efficiency Computer network reliability Transmitting antennas Modulation Symbols Downlink

基于曲面拟合的离轴非球面镜顶点半径计算方法

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红外与激光工程 2014年第8期43卷 2694-2698页

作者：郭玲玲任建岳张星祥张立国赵其昌吴泽鹏中国科学院长春光学精密机械与物理研究所吉林长春130033 上海卫星工程研究所上海200240

为了解决大口径、离轴非球面顶点半径等参数测量不准的问题,提出了一种基于曲面拟合的非球面参数计算方法。建立了测量坐标系下的非球面准确方程,给出了非线性最小二乘拟合的迭代算法。同时提出了采用补偿器端面数据拟合得到光轴指向,... 详细信息

为了解决大口径、离轴非球面顶点半径等参数测量不准的问题,提出了一种基于曲面拟合的非球面参数计算方法。建立了测量坐标系下的非球面准确方程,给出了非线性最小二乘拟合的迭代算法。同时提出了采用补偿器端面数据拟合得到光轴指向,通过测量坐标系下的光轴指向给出合适的拟合初值。对实测数据的实验表明,拟合优度的确定系数接近1,均方根误差约为0.0026mm,计算结果的顶点半径偏离设计值0.0188%。该方法可用于非球面检测阶段的参数计算分析,尤其是计算高精度的顶点半径值,为系统光机装调提供有效的数据支持。

关键词：光学检测非球面检测顶点半径曲面拟合

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

Bandgap adjustment of a sandwich-like acoustic metamaterial plate with a frequency-displacement feedback control method

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Applied Mathematics and Mechanics(English Edition) 2024年第10期45卷 1807-1820页

作者： Jianing LIU Jinqiang LI Ying wu School of Aerospace Engineering Xi’an Jiaotong UniversityXi’an 710049China College of Aerospace and Civil Engineering Harbin Engineering UniversityHarbin 150001China

Several types of acoustic metamaterials composed of resonant units have been developed to achieve low-frequency *** most of these structures,bandgaps are determined by their geometric configurations and material *** paper presents a frequency-displacement feedback control method for vibration suppression in a sandwich-like acoustic metamaterial *** band structure is theoretically derived using the Hamilton principle and validated by comparing the theoretical calculation results with the finite element simulation *** this method,the feedback voltage is related to the displacement of a resonator and the excitation *** applying a feedback voltage on the piezoelectric fiber-reinforced composite(PFRC)layers attached to a cantilever-mass resonator,the natural frequency of the resonator can be *** ensures that the bandgap moves in a frequency-dependent manner to keep the excitation frequency within the *** on this frequency-displacement feedback control strategy,the bandgap of the metamaterial plate can be effectively adjusted,and the vibration of the metamaterial plate can be significantly suppressed.

关键词： acoustic metamaterial Hamilton principle electromechanical coupling vibration control local resonance

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 UniversityBeijing 100875China

Exclusive hypothesis testing is a new and special class of hypothesis *** kind of testing can be applied in survival analysis to understand the association between genomics information and clinical information about the survival ***,it is well known that Cox's proportional hazards model is the most commonly used model for regression analysis of failure *** this paper,the authors consider doing the exclusive hypothesis testing for Cox's proportional hazards model with right-censored *** authors propose the comprehensive test statistics to make decision,and show that the corresponding decision rule can control the asymptotic TypeⅠerrors and have good powers in *** 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

Development of component stiffness equations for thread-fixed one-side bolt connections to an enclosed rectangular hollow section column under tension

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 568-586页

作者： Fu-Wei wu Yuan-Qi LI Department of Structural Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

The derivation and validation of analytical equations for predicting the tensile initial stiffness of threadfixed one-side bolts(TOBs),connected to enclosed rectangular hollow section(RHS)columns,is presented in this *** unknown stiffness components are considered:the TOBs connection and the enclosed RHS ***,the trapezoidal thread of TOB,as an equivalent cantilevered beam subjected to uniformly distributed loads,is analyzed to determine the associated *** on the findings,the thread-shank serial-parallel stiffness model of TOB connection is *** analysis of the tensile stiffness of the enclosed RHS face due to two bolt forces,the four sidewalls are treated as rotation constraints,thus reducing the problem to a two-dimensional plate *** to the load superposition method,the deflection of the face plate is resolved into three components under various boundary and load *** to the plate deflection theory of Timoshenko,the analytical solutions for the three deflections are derived in terms of the variables of bolt spacing,RHS thickness,height to width ratio,***,the validity of the above stiffness equations is verified by a series of finite element(FE)models of T-stub *** proposed component stiffness equations are an effective supplement to the component-based method.

关键词： initial stiffness component based method thread-fixed one-side bolt rectangular hollow sections analytical equation

Preparation of a zeolite-palladium composite membrane for hydrogen separation:Influence of zeolite film on membrane stability

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Chinese Journal of Chemical Engineering 2024年第8期72卷 44-52页

作者： Hongmei wu Xinyu Liu Yu Guo School of Chemical and Environmental Engineering Liaoning University of TechnologyJinzhou 121001China

With the development of hydrogen energy,palladium-based membranes have been widely used in hydrogen separation and ***,the poor chemical stability of palladium composite membranes limits their commercial *** this study,a zeolite-palladium composite membrane with a sandwich-like structure was obtained by using a TS-1 zeolite film grown on the surface of palladium *** membrane microstructure was characterized by SEM and *** effects of the TS-1 film on the hydrogen permeability and stability of palladium composite membrane were investigated in *** from the protection of the TS-1 zeolite film,the stability of palladium composite membrane was *** results indicate that the TS-1-Pd composite membrane was stable after eight cycles of the temperature exchange cycles between 773 K and 623 ***,the loss of hydrogen permeance for TS-1-Pd composite membrane was much smaller than that of the pure palladium membrane when the membrane was tested in the presence of *** indicated that the TS-1-Pd composite membrane had better chemical stability in comparison with pure palladium membrane,owing to its sandwich-like *** work provides an efficient way for the deposition of zeolite film on palladium membrane to enhance the membrane stability.

关键词： Palladium membrane Zeolite film Hydrogen separation Stability

Resource Allocation to Minimize the Makespan with Multi-Resource Operations

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Journal of Systems Science & Complexity 2024年第5期37卷 2054-2070页

作者： WENG wuyan CHU Chengbin wu Peng School of Economics and Management Fuzhou UniversityFuzhou 350108China Univ Gustave Eiffel ESIEE Paris&COSYS-GRETTIAF-77454 Marne-la-ValléeFrance

This paper investigates a new resource-allocation problem involving multi-resource operations,where completing an operation requires simultaneous use of multiple(renewable)resources,probably of different *** goal of the study is to provide a solution method that minimizes the *** authors formulate the problem into a novel mixed-integer linear program(MILP)*** efficiently solve practical-sized instances,an exact Benders decomposition algorithm is *** algorithm divides the original problem into a master problem of allocating resources and a subproblem of calculating the makespan,and both are linked via Benders *** convergence is sped up by improving the mathematical model and embedding the variable neighborhood search *** with CPLEX,a commonly used MILP solver,the computational results demonstrate that the proposed algorithm provides tighter upper and lower bounds in most *** particular,compared with CPLEX,the proposed method can on average improve the upper and lower bounds by 4.76%and 4.39%,respectively,in solving practical-sized instances.

关键词： Benders decomposition multi-resources operations resource allocation

Nonlinear aeroelastic analysis of a twin-tail boom UAV with rudder freeplay nonlinearities

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Chinese Journal of Aeronautics 2024年第9期37卷 276-296页

作者： Liuyue BAI Zhigang wu Chao YANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 10019lChina

The issue of nonlinear structural freeplays in aircraft has always been a significant *** study investigates the aeroelastic characteristics of a twin-tail boom Unmanned Aerial Vehicle(UAV)with simultaneous freeplay nonlinearity in its left and right rudders.A comprehen-sive Limit Cycle Oscillation(LCO)solution route is proposed for complex aircraft with multiple freeplays,which can consider both accuracy and *** the first time,this study reveals the unique LCO characteristics exhibited by twin-tail boom UAVs with rudder freeplays and pro-vides simulations and explanations of interesting phenomena observed during actual *** governing equations are established using the free-interface component mode synthesis method,and the LCOs of the system are mainly solved through the improved time-domain numerical con-tinuation method and frequency-domain numerical continuation ***,the study investigates the influence of the left and right rudder freeplay size ratio on the LCO *** results demonstrate that the twin-tail boom UAV exhibits two stable LCO types:close and dif-fering left and right rudder *** proposed method successfully describes the complete LCO behaviors of the ***,this study makes significant contributions to our understand-ing of the aeroelastic behavior of twin-tail boom UAVs with rudder freeplays.

关键词： Aeroelasticity Freeplay nonlinearity Limit cycle oscillation Numerical continuation Component mode synthesis

Conduction-convection coupled heat transfer around a hollow cylinder under different buoyancy forces

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Chinese Journal of Aeronautics 2024年第4期37卷 216-228页

作者： Wanyu ZHANG Jingyi wu Guang YANG Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China

In order to clarify the effect of a buoyancy force on conduction–convection coupled heat transfer in a hollow cylinder, the flow and thermal characteristics were analyzed using an RNG k-ε turbulence model. The Reynolds number was fixed at 1.014 × 10^(6), and the Rayleigh number varied from 1.122 × 10^(10)to 1.088 × 10^(11). Results have shown that, when considering the effect of an opposed buoyancy force, increasing the Rayleigh number has a positive impact on the rate of change and uniformity of the cylinder temperature. The temperature distributions along the axial and circumferential directions are similar for different Rayleigh numbers, but extreme values *** the axial direction, the maximum temperature is obtained at the interface between the variable-diameter part and the constant-diameter part. The maximum dimensionless temperature value decreases to 0.12 when the Rayleigh number increases to 1.088 × 10^(11). Along the circumferential direction, the temperature distribution is affected by the buoyancy force, which results in the temperature of the upper part being higher than that of the lower part. After nondimensionalization of the temperature and time, a correlation was proposed to illustrate the transient heat transfer process quantitatively. The standard deviation of the maximum relative temperature, representing the temperature uniformity, was also calculated. It was found that the difference in the direction of the buoyancy force made a huge difference. Compared with the opposed buoyancy force, the maximum dimensionless temperature is almost two times higher with an assisted buoyancy force. Similarly, the heat transfer coefficient with an assisted buoyancy force is half of that with an opposed buoyancy force. Overall, an assisted buoyancy force plays a negative role in terms of thermal characteristics. The flow field around the hollow cylinder was also illustrated to reveal the mechanism of the buoyancy force on magnitude and direction aspects

关键词： Buoyancy Conduction-convection heat transfer Transient analysis Hollow cylinder Non-dimensionalization