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| 1 | MIMO雷达检测性能显示文摘为了充分利用多入多出(multiple input multipleoutput,MIMO)雷达的空间分集技术,同时使其便于设计和实现,论文基于目标的分布源模型,在Neyman-Pearson准则下研究当MIMO雷达分集路径不完全独立时的检测方法和性能,并且利用主分量分析的思想简化了检测方法。该方法通过特征值分解,从M个正交信号中提取出独立观测分量并将其加权合并。仿真结果表明:与传统雷达相比,只要存在2个以上的独立观测分量,MIMO雷达可以更有效地对抗目标RCS(radar cross section)闪烁。同时,当发射阵元间距减小为理想条件的1/4时,MIMO雷达仍然可以利用空间分集提高其检测性能。 | 戴喜增 彭应宁 汤俊 | 2007 | 清华大学学报(自然科学版)2007，47，1： | 46 |
| 2 | Seismic damage-cracking analysis of arch dams using different earthquake input mechanisms显示文摘In this study, a nonlinear model is presented for analysis of damage-cracking behavior in arch dams during strong earthquakes using different seismic input mechanisms. The nonlinear system includes a plastic-damage model for cyclic loading of concrete considering strain softening and a contact boundary model of contraction joint opening. Two different earthquake input mechanisms are used for comparison, including massless foundation input model and viscous-spring boundary model considering radiation damping due to infinite canyon. The results demonstrate that effects of seismic input mechanism and radiation damping on nonlinear response and damage-cracking of the dam are significant. Compared with the results of using massless foundation input model, the damage-cracking region and contraction joint opening are substantially reduced when using viscous-spring boundary model to take into account radiation damping. However, if the damping ratio of the dam is artificially increased to about 10%―15% for massless foundation input model, the joint opening and damage-cracking of the dam are comparable to the results obtained from the viscous-spring boundary model. | JianWen Pan ChuHan Zhang JinTing Wang YanJie Xu | 2009 | Science China(Technological Sciences)2009，52，2： | 18 |
| 3 | Design of integrated radar and communication system based on MIMO-OFDM waveform显示文摘Orthogonal frequency division multiplexing(OFDM)waveform enables radar and communication functions simultaneously, which encounters low angle resolution and poor data rate for traditional single input single output(SISO) systems. To solve these problems, an integrated radar and communication system(IRCS) with multiple input multiple output(MIMO) OFDM waveform is proposed. The different limitations of radar and communication in designing such a system are investigated. Then, an optimization problem is devised to obtain suitable system parameters, including the number of subcarriers, subcarrier spacing, number of symbols,pulse repetition frequency(PRF) and length of cyclic prefix(CP).Finally, to satisfy the requirements of both radar and communication, the IRCS parameters are derived in three typical cases.Several numerical results are presented to illustrate the demands of radar and communication, inconsistent or consistent, for the IRCS parameters and the superiority of the proposed system. | Yongjun Liu Guisheng Liao Zhiwei Yang Jingwei Xu | 2017 | Journal of Systems Engineering and Electronics2017，28，4： | 16 |
| 4 | 一组提高存储效率的深度包检测算法显示文摘随着深度包检测规则数目的剧烈增长,为了适应网络处理的需求,必须对表示正则表达式的DFA(deterministic finite automata,确定的有限自动机)进行高效的存储.一方面,对DFA的状态点数目进行压缩,提出了一种复合的FSM(有限自动机)的构造方法,通过对正则表达转化成DFA的状态点数目复杂度的分析,将不同复杂度的正则表达式采用不同的方式构建DFA,使得所有平方级和指数级复杂度的状态点数目降低到了线性级.另一方面,对DFA的状态转移数目进行压缩,给出了一种高效的压缩算法,即WD2FA(weighted delayed input DFA,带权延迟DFA)算法,对于任意复杂度的正则表达式都可以将状态转移数目压缩为原来的5%左右,相对于D2FA(delayed input DFA,延迟的DFA)有更好的压缩能力,并且使得D2FA是WD2FA在权值为0情况下的特例.实验结果表明,有限自动机的状态点数目能够控制在线性级,并且在状态点压缩的基础上将状态转移数目压缩为原来的7%. | 于强 霍红卫 | 2011 | 软件学报2011，22，1： | 14 |
| 5 | An effective and practical method for solving an unnegligible problem inherent in the current calculation model for multi-support seismic analysis of structures显示文摘In the seismic analysis of extended structures subject to spatially varying motions, the displacement input model instead of acceleration model is usually adopted for accurate results. In this paper, a more detailed and comprehensive analysis of the displacement input model is carried out and the research shows that there exists an unnegligible problem in the current displacement model, which leads to the irrationality and unconvergence of some calculated results such as base shear etc. Based on the situation, an effective method named massless rigid element (MRE) method is presented to solve the problem. Moreover, the rationality and accuracy of the method are further assessed and the method is applied to a transmission tower-line system project using the commercially available structural analysis software SAP2000. The theoretical and numerical analyses indicate that the MRE approach is not only feasible with sufficient computational accuracy but also practical and can be easily implemented using the commercially available finite element software such as SAP2000. | LIU GuoHuan2, GUO Wei1 & LI HongNan2 1 National Engineering Laboratory for High Speed Railway Construction, School of Civil Engineering and Architecture, Central South University, Changsha 410075, China 2 Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, China | 2010 | Science China(Technological Sciences)2010，53，7： | 12 |
| 6 | Comparison of carbon sequestration efficiency in soil aggregates between upland and paddy soils in a red soil region of China显示文摘There is limited information on carbon sequestration efficiency(CSE)of soil aggregates in upland and paddy soils under long-term fertilization regimes.In a red soil region of southern China,an upland soil experiment started in 1986 and a paddy soil experiment commenced in 1981.These experiments were conducted using different fertilization treatments.After 30 years,soil organic carbon(SOC)content and stock of different aggregate components were analyzed.The results showed that the SOC contents and stocks in upland soil were lower than in paddy soil.In both upland and paddy soils,the SOC contents and stocks of all aggregate components in NPKM(combined treatment with chemical nitrogen(N),phosphorus(P),potassium(K)fertilizers and manure)were the highest among all treatments.Compared with CK(no fertilizer),SOC content of all aggregate components in NPKM was increased by 13.21–63.11%and 19.13–73.33%in upland and paddy soils,respectively.Meanwhile,the change rates in SOC stock of all aggregate components in upland soil were lower than in paddy soil,although the change rate of SOC stock of all aggregate components in NPKM was higher than in other treatments.Furthermore,a linear equation could fit the relationships between carbon(C)input and change rate of SOC stock(P<0.05).Results indicated that the sum of CSE from all aggregate components in upland soil(16.02%)was higher than that of paddy soil(15.12%)in the same climatic condition and from the same parent material.However,the CSEs from all aggregates were higher than that of bulk soil,although the result from bulk soil also showed that the CSE of upland soil was higher than that of paddy soil. | LIU Kai-lou HUANG Jing LI Da-ming YU Xi-chu YE Hui-cai HU Hui-wen HU Zhi-hua HUANG Qing-hai ZHANG Hui-min | 2019 | Journal of Integrative Agriculture2019，18，6： | 12 |
| 7 | 一种抑制严重非均匀杂波的机载MIMO-STAP方法显示文摘在机载MIMO雷达体制下,针对严重非均匀环境(包括斜视阵和前视阵近程段),提出了一种新的基于时域平滑的两级级联降维STAP方法,先后对杂波和孤立干扰进行抑制.第一级对少量独立同分布(IID)辅助样本进行平滑,用得到的所有样本估计杂波特性并用先时后空自适应级联处理器(称为mDT-SAP)中的3DT-SAP(简称3DT)方法进行抑制,第二级用待检测距离单元数据进行平滑估计孤立干扰特性并用3DT方法进行抑制.该方法克服了直接数据域(DDD)方法空时孔径损失大,误差鲁棒性差及没有充分利用统计信息的缺点,具有良好的性能.计算机仿真实验验证了其有效性和优越性. | 李彩彩 廖桂生 朱圣棋 吴孙勇 | 2011 | 电子学报2011，39，3： | 12 |
| 8 | Consensus Problem of Heterogeneous Multi-agent Systems with Time Delay under Fixed and Switching Topologies显示文摘Consensus problem is investigated for heterogeneous multi-agent systems composed of first-order agents and second-order agents in this paper. Leader-following consensus protocol is adopted to solve consensus problem of heterogeneous multi-agent systems with time-varying communication and input delays. By constructing Lyapunov-Krasovkii functional, sufficient consensus conditions in linear matrix inequality(LMI) form are obtained for the system under fixed interconnection topology. Moreover, consensus conditions are also obtained for the heterogeneous systems under switching topologies with time delays. Simulation examples are given to illustrate effectiveness of the results. | Ping-Ping Dai Cheng-Lin Liu Fei Liu | 2014 | International Journal of Automation and computing2014，11，3： | 11 |
| 9 | Seismic wave input method for three-dimensional soil-structure dynamic interaction analysis based on the substructure of artificial boundaries显示文摘The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the fi nite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave fi eld on the nodes of the substructure composed of elements that contain artifi cial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artifi cial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplifi ed by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verifi ed by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves. | Liu Jingbo Tan Hui Bao Xin Wang Dongyang Li Shutao | 2019 | Earthquake Engineering and Engineering Vibration2019，18，4： | 11 |
| 10 | 大线能量焊接船板EH40电渣焊接头组织和性能显示文摘对60mm厚船板EH40进行了线能量达530kJ/cm的电渣焊试验,并对焊接接头的组织和冲击性能进行了表征。组织分析结果表明:焊接接头粗晶热影响区由针状铁素体、多边形铁素体及晶界铁素体构成,该区宽度约为1mm;焊缝区由尺寸约为10μm的针状铁素体及晶界铁素体构成;熔合区除针状铁素体和晶界铁素体外,还有少量侧板条铁素体。力学性能测试结果表明:焊缝区、熔合区、粗晶热影响区-20℃冲击功均≥60J,且焊后热影响区没有明显软化现象,接头性能满足要求。 | 李小宝 张宇 潘鑫 | 2013 | 钢铁研究学报2013，25，9： | 11 |
| 11 | 气候变暖对中国不同地区农业的影响显示文摘Based on the China Rural Statistical Yearbook of 1984-2003 published by State Statistics Bureau,and the annual temperature in the same period,impacts of temperature change,agricultural input,and planting area on grin production were analyzed for different regions of China during the last 20 years.The results show that the main characteristic of climate warming has obviously promoted the increase of grain yield in Northeast China.but to some extent suppressed it in North China,Northwest China and Southwest China,and shown no obvious effect on it in East China and Central-South China.The increase in agricultural input facilitated the grain production obviously in various regions in the early stage of the past 20 years,but showed no obvious effect in the late stage.The continuous reduction in sown area had a significant negative effect on the grain production in East China and Central-South China. | 刘颖杰 林而达 | 2008 | 气候变化研究进展2008，4，z1： | 9 |
| 12 | Adaptive Control Based on Neural Networks for an Uncertain 2-DOF Helicopter System With Input Deadzone and Output Constraints显示文摘In this paper, a study of control for an uncertain2-degree of freedom(DOF) helicopter system is given. The2-DOF helicopter is subject to input deadzone and output constraints. In order to cope with system uncertainties and input deadzone, the neural network technique is introduced because of its capability in approximation. In order to update the weights of the neural network, an adaptive control method is utilized to improve the system adaptability. Furthermore, the integral barrier Lyapunov function(IBLF) is adopt in control design to guarantee the condition of output constraints and boundedness of the corresponding tracking errors. The Lyapunov direct method is applied in the control design to analyze system stability and convergence. Finally, numerical simulations are conducted to prove the feasibility and effectiveness of the proposed control based on the model of Quanser's 2-DOF helicopter. | Yuncheng Ouyang Lu Dong Lei Xue Changyin Sun | 2019 | IEEE/CAA Journal of Automatica Sinica2019，6，3： | 9 |
| 13 | The enrichment characteristics of mercury in the sediments of Dongjiu and Xijiu, Taihu Lake catchment, in the past century显示文摘The concentration and the enrichment factors of mercury (Hg) in the sediment cores of Dongjiu and Xijiu, Taihu Lake catchment, were studied. The accumulation fluxes, anthropogenic input concentration and anthropogenic accumulation fluxes of Hg in recent 100 years were also analyzed based on the 210Pb dating. The results indicate that the increasing concentrations of Hg in the sediments are influ-enced by natural factors and anthropogenic input simultaneously. Generally, about 2/3 of the Hg in the sediment was from anthropogenic sources. In the early 20th century, the anthropogenic input was owing to the urban development and fossil fuel consumptions surrounding the Taihu Lake and the worldwide atmospheric deposition of Hg since the industrial revolution. The concentration and an-thropogenic fluxes of Hg increased with the industrial development in the catchment since the 1930s. It reached the maximum during the middle 1970s and middle 1990s, and decreased since the middle 1990s with constraints on high pollution industries. | WU YanHong JIANG XueZhong LIU EnFeng YAO ShuChun ZHU YuXin SUN ZhaoBin | 2008 | Science China Earth Sciences2008，51，6： | 8 |
| 14 | On the heterogeneous microstructure development in the welded joint of 12MnNiVR pressure vessel steel subjected to high heat input electrogas welding显示文摘Microstructure features of 12 MnNiVR pressure vessel steel welded joint deposited by the high heat input electrogas welding have been systematically investigated. It is revealed that the welded joint is featured by a heterogeneous juxtaposition. The coarse grained heat-affected zone(CGHAZ) primarily consists of lath bainites and minor granular bainites. The fine grained heat-affected zone(FGHAZ) is dominated by polygonal ferrites, pearlites, and fine cementite particles. Moreover, electron backscatter diffraction results further demonstrate that the CGHAZ is populated by coarse prior austenite grains(PAGs) with high frequency(61.3%) of low angle grain boundaries(LAGBs). On the other hand, the FGHAZ is filled with fine PAGs with a lower frequency(19.6%) of LAGBs. Such microstructural differences may likely contribute to differed mechanical properties for samples tested at designed positions. | Yang Shen Ju Leng Cong Wang | 2019 | Journal of Materials Science & Technology2019，35，8： | 8 |
| 15 | Robust extended Kalman filter with input estimation for maneuver tracking显示文摘This study investigates the problem of tracking a satellite performing unknown continuous maneuvers. A new method is proposed for estimating both the state and maneuver acceleration of the satellite. The estimation of the maneuver acceleration is obtained by the combination of an unbiased minimum-variance input and state estimation method and a low-pass filter. Then a threshold-based maneuver detection approach is developed to determinate the start and end time of the unknown maneuvers. During the maneuvering period, the estimation error of the maneuver acceleration is modeled as the sum of a fluctuation error and a sudden change error. A robust extended Kalman filter is developed for dealing with the acceleration estimate error and providing state estimation. Simulation results show that, compared with the Unbiased Minimum-variance Input and State Estimation(UMISE) method, the proposed method has the same position estimation accuracy, and the velocity estimation error is reduced by about 5 times during the maneuver period. Besides, the acceleration detection and estimation accuracy of the proposed method is much higher than that of the UMISE method. | Yuzi JIANG Hexi BAOYIN | 2018 | Chinese Journal of Aeronautics2018，31，9： | 7 |
| 16 | Robust adaptive compensation control for unmanned autonomous helicopter with input saturation and actuator faults显示文摘This paper studies a robust adaptive compensation Fault Tolerant Control(FTC)for the medium-scale Unmanned Autonomous Helicopter(UAH)in the presence of external disturbances,actuator faults and input saturation.To improve the disturbance rejection capacity of the UAH system in actuator healthy case,an adaptive control method is adopted to cope with the external disturbances and a nominal controller is proposed to stabilize the system.Meanwhile,compensation control inputs are designed to reduce the negative effects derived from actuator faults and input saturation.Based on the backstepping control and inner-outer loop control technologies,a robust adaptive FTC scheme is developed to guarantee the tracking errors convergence.Under the presented FTC controller,the uniform ultimate boundedness of all closed-loop signals is ensured via Lyapunov stability analysis.Simulation results demonstrate the effectiveness of the proposed control algorithm. | Kun YAN Mou CHEN Qingxian WU Ronggang ZHU | 2019 | Chinese Journal of Aeronautics2019，32，10： | 6 |
| 17 | User Assisted Cooperative Relaying in Beamspace Massive MIMO NOMA Based Systems for Millimeter Wave Communications显示文摘A novel scheme‘user assisted cooperative relaying in beamspace massive multiple input multiple output(M-MIMO)non-orthogonal multiple access(NOMA)system’has been proposed to improve coverage area,spectrum and energy efficiency for millimeter wave(mmWave)communications.A downlink system for M users,where base station(BS)is equipped with beamforming lens antenna structure having NRF radio frequency(RF)chains,has been considered.A dynamic cluster of users is formed within a beam and the intermediate users(in that cluster)between beam source and destination(user)act as relaying stations.By the use of successive interference cancellation(SIC)technique of NOMA within a cluster,the relaying stations relay the symbols with improved power to the destination.For maximizing achievable sum rate,transmit precoding and dynamic power allocation for both intra and inter beam power optimization are implemented.Simulations for performance evaluation are carried out to validate that the proposed system outperforms the conventional beamspace M-MIMO NOMA system for mmWave communications in terms of spectrum and energy efficiency. | Jaipreet Kaur Maninder Lal Singh | 2019 | China Communications2019，16，6： | 6 |
| 18 | High precision attitude dynamic tracking control of a moving space target显示文摘On-orbit spacecraft face many threats,such as collisions with debris or other spacecraft.Therefore,perception of the surrounding space environment is vitally important for on-orbit spacecraft.Spacecraft require a dynamic attitude tracking ability with high precision for such missions.This paper aims to address the above problem using an improved backstepping controller.The tracking mission is divided into two phases:coarse alignment and fine alignment.In the first phase,a traditional saturation controller is utilized to limit the maximum attitude angular velocity according to the actuator’s ability.For the second phase,the proposed backstepping controller with different virtual control inputs is applied to track the moving target.To fulfill the high precision attitude tracking requirements,a hybrid attitude control actuator consisting of a Control Moment Gyro(CMG)and Reaction Wheel(RW)is constructed,which can simultaneously avoid the CMG singularity and RW saturation through the use of an angular momentum optimal management strategy,such as null motion.Finally,five simulation scenarios were carried out to demonstrate the effectiveness of the proposed control strategy and hybrid actuator. | Yunhua WU Mohong ZHENG Wei HE Feng WANG Zhiming CHEN Bing HUA | 2019 | Chinese Journal of Aeronautics2019，32，10： | 6 |
| 19 | A review on application of dielectric barrier discharge plasma technology on the abatement of volatile organic compounds显示文摘Volatile organic compounds(VOCs)released from the waste treatment facilities have become a significant issue because they are not only causing odor nuisance but may also hazard to human health.Non-thermal plasma(NTP)technologies are newly developed methods and became a research trend in recent years regarding the removal of VOCs from the air stream.Due to its unique characteristics,such as rapid response at room temperature,bulk homogenized volume,high reaction efficiency,dielectric barrier discharge(DBD)plasma technology is considered one of the most promising techniques of NTP.This paper reviews recent progress of DBD plasma technology for abatement of VOCs.The principle of plasma generation in DBD and its configurations(electrode,discharge gap,dielectric barrier material,etc.)are discussed in details.Based on previously published literature,attention has been paid on the effect of DBD configuration on the removal of VOCs.Effect of various process parameters such as initial concentration,gas feeding rate,oxygen content and input power on VOCs removal are also considered.Moreover,the role of catalysis and inhibitors in VOCs removal by DBD system are presented.Finally,a modified configuration of the DBD reactor,i.e.double dielectric barrier discharge(DDBD)for the abatement of VOCs is discussed.It was suggested that the DDBD plasma reactor could be used for higher conversion efficiency as well as for avoiding solid residue deposition on the electrode.These depositions can interfere with the performance of the reactor. | Wenjing Lu Yawar Abbas Muhammad Farooq Mustafa Chao Pan Hongtao Wang | 2019 | Frontiers of Environmental Science & Engineering2019，13，2： | 6 |
| 20 | Neural Network Based Adaptive Tracking Control for a Class of Pure Feedback Nonlinear Systems With Input Saturation显示文摘In this paper, an adaptive neural networks(NNs)tracking controller is proposed for a class of single-input/singleoutput(SISO) non-affine pure-feedback non-linear systems with input saturation. In the proposed approach, the original input saturated nonlinear system is augmented by a low pass filter.Then, new system states are introduced to implement states transformation of the augmented model. The resulting new model in affine Brunovsky form permits direct and simpler controller design by avoiding back-stepping technique and its complexity growing as done in existing methods in the literature.In controller design of the proposed approach, a state observer,based on the strictly positive real(SPR) theory, is introduced and designed to estimate the new system states, and only two neural networks are used to approximate the uncertain nonlinearities and compensate for the saturation nonlinearity of actuator. The proposed approach can not only provide a simple and effective way for construction of the controller in adaptive neural networks control of non-affine systems with input saturation, but also guarantee the tracking performance and the boundedness of all the signals in the closed-loop system. The stability of the control system is investigated by using the Lyapunov theory. Simulation examples are presented to show the effectiveness of the proposed controller. | Nassira Zerari Mohamed Chemachema Najib Essounbouli | 2019 | IEEE/CAA Journal of Automatica Sinica2019，6，1： | 5 |
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