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Frontiers of Computer Science 2022年第6期16卷 191-193页

作者： guangyan ZHOU Wei xu Department of Mathematics Beijing Technology and Business UniversityBeijing 100048China School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China

1 Introduction Constraint satisfaction problems(CSPs)have come to play a prominent role in the area of computer science,statistical physics and information theory.A CSP instance involves a set of variables and a set of constraints,and the task is to find a solution(an assignment of variables that satisfies all the constraints)or to prove the unsolvability.Model RB[1]is a CSP model proposed to overcome the trivial unsatisfiability of standard Model B[2].

关键词： theory. constraints trivial

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Nano-sized alumina supported palladium catalysts for methane combustion with excellent thermal stability

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Journal of Environmental Sciences 2023年第4期126卷 333-347页

作者： Wei Shi Guangyan Xu xuewang Han Yingjie Wang Zhi Liu Sen xue Nannan Sun Xiaoyan Shi Yunbo Yu Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Weichai Power Co. Ltd.Weifang 261061China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

Pd/Al_(2)O_(3)catalysts supported on Al_(2)O_(3)of different particle sizes were synthesized and applied in methane combustion.These catalysts were systematically characterized by Brunauer-Emmett-Teller (BET),X-ray diffraction (XRD),high resolution-transmission electron microscopy (HR-TEM),high-angle annular dark?eld-scanning transmission electron microscopy (HAADF-STEM),H_(2)-temperature-programmed reduction (H_(2)-TPR),O_(2)-temperature-programmed oxidation (O_(2)-TPO),X-ray photoelectron spectroscopy (XPS),and X-ray absorption?ne structure (XAFS).The characterization results indicated that nanosized Al_(2)O_(3)enabled the uniform dispersion of palladium nanoparticles,thus contributing to the excellent catalytic performance of these nano-sized Pd/Al_(2)O_(3)catalysts.Among them,Pd/Al_(2)O_(3)-nano-10 (Pd/Al_(2)O_(3)supported by alumina with an average particle size of 10 nm)showed superior catalytic activity and stability for methane oxidation under harsh practical conditions.It maintained excellent catalytic performance for methane oxidation for50 hr and remained stable even after harsh hydrothermal aging in 10 vol.%steam at 800℃ for 16 hr.Characterization results revealed that the strong metal-support interactions and physical barriers provided by Al_(2)O_(3)-nano-10 suppressed the coalescence ripening of palladium species,and thus contributed to the superior sintering resistance of the Pd/Al_(2)O_(3)-nano-10 catalyst.

关键词： Methane combustion Pd/Al_(2)O_(3) Hydrothermal stability Metal-support interaction Physical barriers

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Interface sites on vanadia-based catalysts are highly active for NO_(x) removal under realistic conditions

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Journal of Environmental Sciences 2024年第2期136卷 523-536页

作者： Zhihui Lv Guangzhi He Wenshuo Zhang Jingjing Liu Zhihua Lian Yang Yang Zidi Yan Guangyan Xu Wenpo Shan Yunbo Yu Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China Ningbo Research Center for Urban Environment Chinese Academy of SciencesNingbo 315800China

TiO_(2)-supported V_(2)O_(5)catalysts are commonly used in NO_(x)reduction with ammonia due to their robust catalytic performance.Over these catalysts,it is generally considered that the active species are mainly derived from the vanadia species rather than the intrinsic structure of V-O-Ti entities,namely the interface sites.To reveal the role of V-O-Ti entities in NH_(3)-SCR,herein,we prepared TiO_(2)/V_(2)O_(5)catalysts and demonstrated that V-O-Ti entities were more active for NO_(x)reduction under wet conditions than the V sites(V=O)working alone.On the V-O-Ti entities,kinetic measurements and first principles calculations revealed that NH_(3)activation exhibited a much lower energy barrier than that on V=O sites.Under wet conditions,the V-O-Ti interface significantly inhibited the transformation of V=O to V-OH sites thus benefiting NH_(3)activation.Under wet conditions,meanwhile,the migration of NH_(4)^(+)from Ti site neighboring the V-O-Ti interface to Ti site of the V-O-Ti interface was exothermic;thus,V-O-Ti entities together with neighboring Ti sites could serve as channels linking NH_(3)pool and active centers for activation of NH_(4)^(+).This finding reveals that the V-O-Ti interface sites on V-based catalysts play a crucial role in NO_(x)removal under realistic conditions,providing a new perspective on NH_(3)-SCR mechanism.

关键词： NO_(x)removal Vanadia-based catalysts V-O-Ti entities Interface sites Reaction mechanism

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Attitude Control of Quad-Rotor Aircraft with Rudders

Attitude Control of Quad-Rotor Aircraft with Rudders

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第36届中国控制会议

作者： Guangyan Xu Jinshuang Zhang School of Automation Shenyang Aerospace University

ISBN: (纸本)9781538629185

This paper researches the mathematical modeling and attitude control of four-rotor UAV with rudders.The structure of four-rotor with rudders is different from conventional four-rotor.The quaternion is used to describe the attitude of the aircraft in order to avoid the singularity.The mathematical model is derived by choosing reasonable coordinate systems and physical quantities,such that all physical quantities,including the control quantities,are expressed in the model explicitly.Since all state and control quantities in the model are nonlinear,a nonlinear controller is designed based on feedback linearization.The controUer contains two feedback loops:the outer loop of attitude angle and the inner loop of angular velocity.Because of the nonlinear effect of the system,the inner loop feedback is coupled with the attitude angle,which is quite different from the traditional double loop feedback.The simulation results show that the designed control law can make the controlled quantities converge rapidly,and it is suitable for the situation where the attitude angle changes over a wide range.

关键词： Attitude control four-rotor with rudders quaternion feedback linearization

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Power Control of Multi-sensor Remote State Estimation Under Malicious Attacks

Power Control of Multi-sensor Remote State Estimation Under ...

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第三十九届中国控制会议

作者： Guangyan Xu Qiuying Sun Hao Liu School of Automation Shenyang Aerospace University

This paper studies a transmission power control problem in the presence of malicious attacks, in which sensors transmit their local estimates to a remote estimator through independent wireless channels. The sensor’s data transmission performance is assumed to be not affected by the transmission power of other sensors, and a new objective function is proposed to reflect the performance of remote state estimation. Game approaches including Nash and Stackelberg games are utilized to design the optimal strategies for both players, respectively. Moreover, the energy constraints are taken into account for both sides. Finally,simulation examples are provided to illustrate the main results.

关键词： Wireless sensor network remote state estimation cyber attack

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A Novel Tracking Method Based on Improved FAST Corner Detection and Pyramid LK Optical Flow

A Novel Tracking Method Based on Improved FAST Corner Detect...

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第32届中国控制与决策会议

作者： Hongmei Zhang Li Xiao Guangyan Xu Shenyang Aerospace University

Object tracking is a challenging problem with accuracy and large motion in computer vision.Though optical flow has achieved great performance,it would possibly fail to track fast moving object,and accuracy and big movement both suffer from the size of integration window.Pyramid LK（Lucas-Kanade） method can solve large motion in a small integration window.However,the basic pyramid LK is affected by accuracy.So,a combination of improved FAST corner detection and pyramid LK optical flow is applied.In this method,sub-pixel computation can increase the accuracy.The large movement can be satisfied by scaling the source image.The strongest gray changing corner point can be rapidly extracted by the improved FAST algorithm.This approach can better estimate the optical flow with strong corner to track moving object.In the experiment,a video of actual movement of ball is used to test algorithm validity.Average errors in the x direction and y direction are 0.9386 pixel and 0.6792 pixel separately.The detection results demonstrate that this algorithm can track moving target of large motion accurately.

关键词： Optical flow Pyramid LK FAST corner detection and Object tracking

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The optimal false data injection attacks based on zonotopes

The optimal false data injection attacks based on zonotopes

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第三十九届中国控制会议

作者： Guangyan Xu Hui Qiu Hao Liu School of Automation Shenyang Aerospace University

This paper proposes an attack detection method and an optimal false data injection（FDI） attack strategy based on zonotopic theory. A linear discrete-time system with unknown-but-bounded（UBB） noise is considered, and it is assumed that the attacker can obtain the full knowledge of the system. Based on the estimation residue, a novel attack detection method is proposed. In addition, the conditions that an attacker needs to satisfy are given, which can guarantee that attacks are stealthy.Finally, a simulation example is provided to illustrate the effectiveness of the main results.

关键词： linear systems false-data-injection attacks estimation zonotopes

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Consensus-Based Control for Unmanned Aerial Vehicle Formation with Speed Adaptability

Consensus-Based Control for Unmanned Aerial Vehicle Formatio...

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第30届中国控制与决策会议

作者： Hongmei Zhang Ying Li Guangyan Xu School of Automation Shenyang Aerospace University

This paper presents a distributed control method based on consistency control for unmanned aerial vehicles（UAVs） formation flight in three-dimensional space. Aiming at leader-follower model, an elastic distance vector is designed based on the positional relation between the leader and followers and the instantaneous velocity of UAV, which gives the formation speed adaptability. What’s more, a consensus control protocol including communication gain and feedback gain is proposed for the formation. Simulation results verify the correctness and validity of the given controller and show the feasibility and operability of the elastic formation method.

关键词： Formation Control Elastic Distance Vector Consistency control UAVs

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Application of Situation Function in Air Combat Differential Games

Application of Situation Function in Air Combat Differential...

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第36届中国控制会议

作者： Guangyan Xu Shenna Wei Hongmei Zhang School of Automation Shenyang Aerospace University

ISBN: (纸本)9781538629185

The continuous differentiable situation function is addressed and applied to the differential game of unmanned aerial vehicles.Differential game theory is an important means to solve the control problem of air combat.In order to improve the scientific nature of air combat control problem,a two-dimensional mathematical model of differential game between two unmanned aerial vehicles(UAVs) is established and solved by semi-direct method.Numerical simulations were carried out under the different maximum maneuver conditions of two sides.The results indicate that the situation function is successfully applied to the differential game,and the semi-direct method could be used to solve the air combat strategy quickly and accurately.

关键词： Situation function Differential game Air combat Semi-direct method

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Take-off Trajectory optimization of Vertical take off and landing UAV

Take-off Trajectory optimization of Vertical take off and la...

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第36届中国控制会议

作者： Hongmei Zhang Changzhen Liu Guangyan Xu School of Automation Shenyang Aerospace University

In this paper,the take-off trajectory optimization problem for a new vertical takeoff and landing（VTOL） unmanned aerial vehicle（UAV） is studied.The longitudinal kinematics equation and dynamics equation are established with atmospheric density,earth gravity,engine thrust and aerodynamic parameter.Taking the thrust and rudder angles as the control variables,the optimal objective function of the fuel and distance at the given time is proposed.Based on Legendre Pseudospectral method（LPM） the optimal control is transformed into the parameter optimization problem,and the optimal flight trajectory is obtained.The simulation results verify the correctness and effectiveness of the method.

关键词： trajectory optimization VTOL LPM UAV

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