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Journal of Systems Science & Complexity 2024年第1期37卷 136-151页

作者： PAN Zini chen ben m Department of mechanical and Automation Engineering The Chinese University of Hong KongHong KongChina

In this paper,the authors study the cooperative target-fencing problem for n-dimensional systems and a target with a general *** using the velocity of the vehicles,a position feedback control law is proposed to fence the general target into the convex hull formed by the ***,the dynamics of each vehicle is described by a double-integrator *** potential functions are designed to guarantee connectivity preservation of the communication network and collision avoidance among the *** proposed approach can deal with a target whose trajectory is any twice continuously differentiable function of *** effectiveness of the result is verified by a numerical example.

关键词： multi-agent systems networked systems target fencing

Special issue on control theory and technologies in honor of the 70th birthday of Professor Frank ***

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Control Theory and Technology 2019年第1期17卷 1-3页

作者： Huang, Jie chen, ben m. Hongkong China

It is our great pleasure to put up this special issue in Control Theory and Technology in honor of the 70th birthday of Professor Frank L. Lewis, who has made many truly outstanding contributions to the field of systems and control through the years, which includes applied optimal control, geometric systems theory and nonlinear control in his earlier research period, and his recent focus on cooperative multi-age nt distributed systems, reinforceme nt learning in control, wireless sensor networks for area security monitoring and condition-based maintenanee, robotic system control, and manufacturing process control and scheduling to name a few. Featured in this special issue are 10 manuscripts on control theory and tech no logies, of which many are from the personal and academic friends of Professor Frank Lewis.

关键词： Special issue control theory technologies

A hierarchical multi-UAV cooperative framework for infrastructure inspection and reconstruction

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Control Theory and Technology 2024年第3期22卷 394-405页

作者： Chuanxiang Gao Xinyi Wang Xi chen ben m.chen Department of mechanical and Automation Engineering The Chinese University of Hong KongHong KongShatinNTChina

Unmanned aerial vehicles(UAVs)are emerging as a powerful tool for inspections and repair works in large-scale and unstructured 3D infrastructures,but current approaches take a long time to cover the entire *** using UAVs for inspections and repair works puts forward a requirement of improving time efficiency in large-scale and cluster *** paper presents a hierarchical multi-UAV cooperative framework for infrastructure inspection and reconstruction to balance the workload and reduce the overall task completion *** proposed framework consists of two stages,the exploration stage and the exploitation stage,resolving the task in a sequential *** the exploration stage,the density map is developed to update global and local information for dynamic load-balanced area partition based on reconstructability and relative positions of UAVs,and the Voronoi-based planner is used to enable the UAVs to reach their best *** obtaining the global map,viewpoints are generated and divided while taking into account the battery capacity of each ***,a shortest path planning method is used to minimize the total traveling cost of these viewpoints for obtaining a high-quality *** experiments are conducted in both a simulated and real environment to show the time efficiency,robustness,and effectiveness of the proposed ***,the whole system is implemented in real applications.

关键词： multi-UAV Coverage path planning Infrastructure inspection and reconstruction

Development of a vision-based ground target detection and tracking system for a small unmanned helicopter

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Science in China(Series F) 2009年第11期52卷 2201-2215页

作者： LUm Kai-Yew chen ben m. LEE Tong H. Department of Electrical & Computer Engineering National University of Singapore

It is undoubted that the latest trend in the unmanned aerial vehicles （UAVs） community is towards vision-based unmanned small-scale helicopter, utilizing the maneuvering capabilities of the helicopter and the rich information of visual sensors, in order to arrive at a versatile platform for a variety of applications such as navigation, surveillance, tracking, etc. In this paper, we present the development of a vision-based ground target detection and tracking system for a small UAV helicopter. more specifically, we propose a real-time vision algorithm, based on moment invariants and two-stage pattern recognition, to achieve automatic ground target detection. In the proposed algorithm, the key geometry features of the target are extracted to detect and identify the target. Simultaneously, a Kalman filter is used to estimate and predict the position of the target, referred to as dynamic features, based on its motion model. These dynamic features are then combined with geometry features to identify the target in the second-stage of pattern recognition, when geometry features of the target change significantly due to noise and disturbance in the environment. Once the target is identified, an automatic control scheme is utilized to control the pan/tilt visual mechanism mounted on the helicopter such that the identified target is to be tracked at the center of the captured images. Experimental results based on images captured by the small-scale unmanned helicopter, SheLion, in actual flight tests demonstrate the effectiveness and robustness of the overall system.

关键词： target tracking unmanned aerial vehicle image processing pattern recognition Kalman filtering

Deep learning based water leakage detection for shield tunnel lining

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Frontiers of Structural and Civil Engineering 2024年第6期18卷 887-898页

作者： Shichang LIU Xu XU Gwanggil JEON Junxin chen ben-Guo HE College of Computer Science Sichuan UniversityChengdu 610065China School of Computer Science and Engineering Northeastern UniversityShenyang 110004China Department of Embedded Systems Engineering Incheon National UniversityIncheon 22012Korea School of Software Dalian University of TechnologyDalian 116621China Key Laboratory of ministry of Education on Safe mining of Deep metal mines Northeastern UniversityShenyang 110819China

Shield tunnel lining is prone to water leakage,which may further bring about corrosion and structural damage to the walls,potentially leading to dangerous *** avoid tedious and inefficient manual inspection,many projects use artificial intelligence(Al)to detect cracks and water leakage.A novel method for water leakage inspection in shield tunnel lining that utilizes deep learning is introduced in this *** proposal includes a ConvNeXt-S backbone,deconvolutional-feature pyramid network(D-FPN),spatial attention module(SPAm).and a detection *** can extract representative features of leaking areas to aid inspection *** further improve the model's robustness,we innovatively use an inversed low-light enhancement method to convert normally illuminated images to low light ones and introduce them into the training *** experiments are performed,achieving the average precision(AP)score of 56.8%,which outperforms previous work by a margin of 5.7%.Visualization illustrations also support our method's practical effectiveness.

关键词： water leakage detection deep learning deconvolutional-feature pyramid spatial attention

molecular insights into oil detachment from hydrophobic quartz surfaces in clay-hosted nanopores during steam-surfactant co-injection

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Petroleum Science 2024年第4期21卷 2457-2468页

作者： ben-Jie-ming Liu Xuan-Tong Lei mohammadali Ahmadi Zhangxin chen Department of Chemical and Petroleum Engineering University of Calgary Eastern Institute of Technology

Thermal recovery techniques for producing oil sands have substantial environmental impacts. Surfactants can efficiently improve thermal bitumen recovery and reduce the required amount of steam. Such a technique requires solid knowledge about the interaction mechanism between surfactants, bitumen,water, and rock at the nanoscale level. In particular, oil sands ores have extremely complex mineralogy as they contain many clay minerals(montmorillonite, illite, kaolinite). In this study, molecular dynamics simulation is carried out to elucidate the unclear mechanisms of clay minerals contributing to the bitumen recovery under a steam-anionic surfactant co-injection process. We found that the clay content significantly influenced an oil detachment process from hydrophobic quartz surfaces. Results reveal that the presence of montmorillonite, illite, and the siloxane surface of kaolinite in nanopores can enhance the oil detachment process from the hydrophobic surfaces because surfactant molecules have a stronger tendency to interact with bitumen and quartz. Conversely, the gibbsite surfaces of kaolinite curb the oil detachment process. Through interaction energy analysis, the siloxane surfaces of kaolinite result in the most straightforward oil detachment process. In addition, we found that the clay type presented in nanopores affected the wettability of the quartz surfaces. The quartz surfaces associated with the gibbsite surfaces of kaolinite show the strongest hydrophilicity. By comparing previous experimental findings with the results of molecular dynamics(mD) simulations, we observed consistent wetting characteristics. This alignment serves to validate the reliability of the simulation outcomes. The outcome of this paper makes up for the lack of knowledge of a surfactant-assisted bitumen recovery process and provides insights for further in-situ bitumen production engineering designs.

关键词： Clay minerals Bitumen Contact angle Interaction energy Surfactant molecular dynamics

Effect of unstable resonator stability on laser beam quality

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Optoelectronics Letters 2024年第9期20卷 523-530页

作者： LIANG Xiaolin BAO ben'gang ZHOU Songqing chen Huihuang College of Intelligent manufacturing Hunan University of Science and EngineeringYongzhou 425199China

In order to explore the effect of unstable resonator stability on laser beam quality,the numerical simulation of midinfrared laser and visible laser was carried out in GLAD *** simulation results showed that the existence of defocus aberration,tilt aberration and astigmatic aberration in the unstable resonator can cause the center of the far-field spot of the output annular beam to drift,the number of peripheral diffraction rings to increase,the beam quality to deteriorate,and the degree of effect is different.

关键词： resonator laser beam

Promising interlayer sensitization strategy for the construction of high-performance blue hyperfluorescence OLEDs

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Light(Science & Applications) 2024年第7期13卷 1372-1382页

作者： Jianghui Wang Peng Zou Letian chen Zhentao Bai Hao Liu Wen-cheng chen Yanping Huo ben Zhong Tang Zujin Zhao State Key Laboratory of Luminescent materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSouth China University of TechnologyGuangzhou 510640China. School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China. School of Science and Engineering Shenzhen Institute of Aggregate Science and TechnologyThe Chinese University of Hong KongShenzhenGuangdong 518172China

multi-resonance thermally activated delayed fluorescence(mR-TADF)materials are promising candidates for organic light-emitting diodes(OLEDs)with narrow electroluminescence(EL)*** researches focus on fabricating hyperfluorescence OLEDs to improve EL efficiencies of mR-TADF emitters by co-doping them with TADF sensitizers in a single host ***,in many cases,the polarity of the single host could be not suitable for both blue mRTADF emitters and blue TADF sensitizers,resulting in broadened EL spectra in high-polar hosts or decreased EL efficiencies in low-polar ***,we wish to report an efficient sensitization strategy for blue mR-TADF emitters by constructing an interlayer-sensitizing configuration,in which the blue TADF sensitizers and blue mR-TADF emitters are separated into two closely aligned host layers with high polarity and low polarity,*** on this strategy,efficient blue hyperfluorescence OLEDs are realized and verified by employing various TADF sensitizers and different mR-TADF emitters,furnishing outstanding external quantum efficiencies of up to 38.8%and narrow EL *** results validate the feasibility and universality of this interlayer sensitization strategy,which provides an effective alternative to high-performance blue hyperfluorescence OLEDs.

关键词： OLEDs interlayer sensitization

Wave Attenuation and Turbulence Driven by Submerged Vegetation Under Current-Wave Flow

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China Ocean Engineering 2024年第4期38卷 602-611页

作者： HUANG Yu-ming Ding Lei WANG Yi-fei chen ben YANG Xiao-yu DOU Xi-ping School of Water Resources and Hydropower Engineering Wuhan UniversityWuhan430072China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China

A set of laboratory experiments are carried out to investigate the effect of following/opposing currents on wave *** vegetation canopies with aligned and staggered configurations were tested under the condition of various regular wave heights and current velocities,with the constant water depth being 0.60 m to create the desired submerged *** show that the vegetation-induced wave dissipation is enhanced with the increasing incident wave height.A larger velocity magnititude leads to a greater wave height attenuation for both following and opposing current ***,there is a strong positive linear correlation between the damping coefficientβand the relative wave height H_(0)/h,especially for pure wave *** the velocity profile,the distributions of U_(min)and U_(max)show different patterns under combined wave and *** time-averaged turbulent kinetic energy(TKE)vary little under pure wave and U_(c)=±0.05 m/s *** the increase of flow velocity amplitude,the time-averaged TKE shows a particularly pronounced increase trend at the top of the *** vegetation drag coefficients are obtained by a calibration *** empirical relations of drag coefficient with Reynolds and Keulegane-Carpenter numbers are proposed to further understand the wave-current-vegetation interaction mechanism.

关键词： wave attenuation rigid vegetation following and opposing currents turbulent kinetic energy

Photo-responsive functional materials based on light-driven molecular motors

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Light(Science & Applications) 2024年第3期13卷 407-420页

作者： Yanping Deng Guiying Long Yang Zhang Wei Zhao Guofu Zhou ben L.Feringa Jiawen chen SCNU-UG International Joint Laboratory of molecular Science and Displays National Center for International Research on Green OptoelectronicsSouth China Normal UniversityGuangzhou 510006China Stratingh Institute for Chemistry University of GroningenNijenborgh 49747AG GroningenThe Netherlands

In the past two decades,the research and development of light-triggered molecular machines have mainly focused on developing molecular devices at the nanoscale.A key scientific issue in the field is how to amplify the controlled motion of molecules at the nanoscale along multiple length scales,such as the mesoscopic or the macroscopic scale,or in a more practical perspective,how to convert molecular motion into changes of properties of a macroscopic ***-driven molecular motors are able to perform repetitive unidirectional rotation upon irradiation,which offers unique opportunities for responsive macroscopic *** several reviews that focus on the design,synthesis and operation of the motors at the nanoscale,photo-responsive macroscopic materials based on light-driven molecular motors have not been comprehensively *** the present review,we first discuss the strategy of confining absolute molecular rotation into relative rotation by grafting motors on ***,examples of self-assemble motors in supramolecular polymers with high internal order are ***,we will focus on building of motors in a covalently linked system such as polymeric gels and polymeric liquid crystals to generate complex responsive ***,a perspective toward future developments and opportunities is *** review helps us getting a more and more clear picture and understanding on how complex movement can be programmed in light-responsive systems and how man-made adaptive materials can be invented,which can serve as an important guideline for further design of complex and advanced responsive materials.

关键词： functions materials material