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Assessment of piloting behavior impact on landing risk of transport aircraft

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Chinese Journal of Aeronautics 2024年第9期37卷 178-192页

作者： Zhiyue XIONG Shuguang ZHANG mingkai wang Peng TANG Mengmeng wang School of Transportation Science and Engineering Beihang UniversityBeijing 102206China

The human factors and their interaction with other factors play an important role in the flight safety of transport *** this paper,a paradigm of risk assessment for transport aircraft interacting with piloting behaviors is proposed,with focus on landing which is the most accident-prone flight stage in aviation safety ***-based flight simulation serves as our data source for landing risk analysis under uncertainties.A digital pilot in the loop that reflects the human piloting behaviors is employed to facilitate simulation *** types of unsafe events in landing are identified from *** this basis,the landing safety boundary is extracted via stochastic simulation to divide safety and hazardous flight status domains,which con-tributes to flight status management and risk *** simulation results indicate that appro-priate piloting behavior,which is active response and fast target acquisition with minimum overshoot and fluctuation,shows benefit to landing *** subset simulation technique is employed to further refine the boundary with less computational ***,the effect of airspeed,windspeed,and other factors on landing risk is also *** proposed risk assess-ment method would help optimize operation procedure and develop targeted pilot training program.

关键词： Landing risk assessment Risk parameterization Human factors Piloting behavior model Landing safety boundary Subset simulation

Abundance and sources of particulate polycyclic aromatic hydrocarbons and aromatic acids at an urban site in central China

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Journal of Environmental Sciences 2024年第8期142卷 155-168页

作者： Luqi Shang Zhe Dong Zihan Li mingkai wang Zihan Kong Xiao Li Ruiqin Zhang School of Ecology and Environment Zhengzhou UniversityZhengzhou 450001China College of Chemistry Zhengzhou UniversityZhengzhou 450001China Institute of Environmental Sciences Zhengzhou UniversityZhengzhou 450001China

We conducted a simultaneous field study of PM_(2.5)-bound particulate polycyclic aromatic hydrocarbons(PAHs)and aromatic acids(AAs)in a polluted city Zhengzhou to explore the concentration,sources and potential conversion pathways between PAHs and AAs in different *** average concentrations of PM_(2.5),28PAHs and 8AAs during the sampling period were 77μg/m^(3),75 ng/m^(3),and 283 ng/m^(3),*** concentration of both28PAHs and 8AAs were highest in winter and lowest in summer with ratios of 6.3 and 2.3,*** with 5-7 rings were the main components of PAHs(52%),followed by 4rings PAHs(30%)and 2-3 rings PAHs(18%).According to the source appointment results obtained by positive matrix factorization,the main sources of PAHs were combustion and vehicle emissions,which account for 37%and 34%,respectively.8AAs were divided into three groups,including four benzene dicarboxylic acids(B2CAs),three benzene tricarboxylic acids(B3CAs)and one benzene tetracarboxylic acid(B4CA).And interspecies correlation analysis with PM_(2.5)source markers were used to investigate potential *** acid(o-Ph)was the most abundant specie of 8AAs(157 ng/m^(3),55%of 8AAs),which was well correlated with ***,B3CAs and B4CA were highly correlated with sulfate and weakly correlated with levoglucosan,suggesting that secondary formation was their main *** logical oxidation products of PAHs,o-Ph and B3CAs showed good correlations with a number of PAHs,indicating possible photochemical oxidation pathway by *** addition,O_(3),NO_(2),temperature and relative humidity have positive effects on the secondary formation of B3CAs.

关键词： Polycyclic aromatic hydrocarbons Aromatic acids Source appointment Secondary formation

锂离子电池动态特性对倾转式eVTOL飞行性能的影响

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推进技术 2024年第3期45卷 222-231页

作者：马劲韬张曙光王明凯北京航空航天大学交通科学与工程学院北京100191 北京理工大学宇航学院北京100081

为准确分析倾转式电动垂直起降飞行器(eVTOL)飞行剖面的变化和锂离子电池的动态特性对飞行性能的影响,结合锂离子电池等主要部件特性建立电动系统模型,提出考虑电池动态特性的eVTOL飞行器性能计算方法,并应用所提出的性能方法对锂离子... 详细信息

为准确分析倾转式电动垂直起降飞行器(eVTOL)飞行剖面的变化和锂离子电池的动态特性对飞行性能的影响,结合锂离子电池等主要部件特性建立电动系统模型,提出考虑电池动态特性的eVTOL飞行器性能计算方法,并应用所提出的性能方法对锂离子电池动态特性的影响进行分析,提炼eVTOL飞行器对电能的需求规律。示例飞行器性能仿真表明,锂离子电池动态特性对动力系统功率产生影响,使悬停垂降时电池输出功率密度仅为垂起悬停阶段的78%;同时影响巡航性能,使巡航末段单位能耗航时和航程相比于起始段减少16%和17%。

关键词：倾转式 eVTOL飞行器飞行性能评估电池动态特性电能需求规律

Battery package design optimization for small electric aircraft

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Chinese Journal of Aeronautics 2020年第11期33卷 2864-2876页

作者： mingkai wang Shuguang ZHANG Johannes DIEPOLDER Florian HOLZAPFEL Institute of Aircraft Airworthiness Engineering School of Transportation Science and EngineeringBeihang UniversityBeijing 100083China Institute of Flight System Dynamics Department of Mechanical EngineeringTechnical University of MunichGarching D-85748Germany

The increasing gross weight of electric Unmanned Aerial Vehicle(UAV) poses a challenge in practical applications. The range and endurance of the electric UAV are limited by the fixed mass of the battery package. In this work, a design optimization method for the battery package topology of small electric UAV is proposed to enhance the performance. To improve the accuracy of the method, the dynamic battery model and simplified electric component models are *** models are utilized by the trajectory optimization method, which takes the dynamic characteristic into consideration to calculate the aircraft performance. The direct optimal control method is used for solving the trajectory optimization problem, and this method is tested on a small blended-wing-body electric aircraft. The test result shows that the range and energy-consumption are mainly influenced by the parallel topology of the battery package, while the flight time in climb phase is more sensitive to the series topology. It is deduced that the range-and energy-optimal design points can be considered concurrently in design optimization. The work proves the feasibility of integrating the trajectory optimization and battery package design.

关键词： Battery pack Design optimization Electric power system Trajectory optimization Unmanned Aerial Vehicle(UAV)

Key technologies for polymer electrolyte membrane fuel cell systems fueled impure hydrogen

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Progress in Natural Science:Materials International 2020年第6期30卷 751-763页

作者： Pucheng Pei mingkai wang Dongfang Chen Peng Ren Lu Zhang State Key Lab.of Automotive Safety and Energy Tsinghua University School of Mechanical-Electronic and Vehicle Engineering Beijing University of Civil Engineering and Architecture

Hydrogen energy and polymer electrolyte membrane(PEM) fuel cells become concerned issues in recent ***, the construction of hydrogen refueling infrastructure and hydrogen storage and transportation constrains the commercial development of fuel cells. In this review, sources, production, storage, transportation,and purification methods of hydrogen are extensively reviewed and compared. The advantages of utilizing industrial by-product hydrogen and steam reforming gas in PEM fuel cell systems are analyzed. Using industrial wasted hydrogen can significantly reduce the cost of hydrogen. Also, it is indicated that the onboard hydrogen generation by steam methanol reforming can solve the difficulties of efficient storage and transportation of gaseous hydrogen, which means that methanol has great potential to be a convenient carrier of hydrogen. The effects of impurities contained in the reformate gas are generally introduced. After the methanol steam reforming and pretreatment purification processes, the reformate gas can be fed to PEM fuel cells. Thus, a fuel cell system integrated with onboard hydrogen production and impure hydrogen treatment subsystems is introduced,and key technologies therein for pretreatment purification and in-situ poisoning mitigation methods are reviewed. Finally, suggestions are proposed for further studies.

关键词： Polymer electrolyte membrane fuel cell system Hydrogen production and storage Steam methanol reforming Impure hydrogen Hydrogen purification

Early Activation of Astrocytes does not Affect Amyloid Plaque Load in an Animal Model of Alzheimer's Disease

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Neuroscience Bulletin 2018年第6期34卷 912-920页

作者： Dongpi wang Xiaoqin Zhang mingkai wang Dongming Zhou Hongyu Pan Qiang Shu Binggui Sun Department of Neurobiology NHC and CAMS Key Laboratory of Medical Neurobiology Zhejiang University School of Medicine Department of Neurology of the First Affiliated Hospital NHC and CAMS Key Laboratory of Medical NeurobiologyZhejiang University School of Medicine Children's Hospital Zhejiang University School of Medicine

Astrocytes are closely associated with Alzheimer’s disease(AD). However, their precise roles in AD pathogenesis remain controversial. One of the reasons behind the different results reported by different groups might be that astrocytes were targeted at different stages of disease progression. In this study, by crossing h APP(human amyloid precursor protein)-J20 mice with a line of GFAP-TK mice, we found that astrocytes were activated specifically at an early stage of AD before the occurrence of amyloid plaques, while microglia were not affected by this crossing. Activation of astrocytes at the age of 3–5 months did not affect the proteolytic processing of hAPP and amyloid plaque loads in the brains of hAPP-J20 mice. Our data suggest that early activation of astrocytes does not affect the deposition of amyloid b in an animal model of AD.

关键词： Astrocyte Alzheimer's disease Amyloid plaque Mouse

Cross-Modal Graph Semantic Communication Assisted by Generative AI in the Metaverse for 6G

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Research 2024年第2期2024卷 19-27页

作者： mingkai Chen Minghao Liu Congyan wang Xingnuo Song Zhe Zhang Yannan Xie Lei wang Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and TelecommunicationsNanjng 210003China State Key Laboratory of Organic Electronics and Information Displays&Institute of Advanced Materials(IAM) Nanjing University of Posts and TelecommunicationsNanjing 210023China

Recently, the development of the Metaverse has become a frontier spotlight, which is an important demonstration of the integration innovation of advanced technologies in the Internet. Moreover, artificial intelligence (AI) and 6G communications will be widely used in our daily lives. However, the effective interactions with the representations of multimodal data among users via 6G communications is the main challenge in the Metaverse. In this work, we introduce an intelligent cross-modal graph semantic communication approach based on generative AI and 3-dimensional (3D) point clouds to improve the diversity of multimodal representations in the Metaverse. Using a graph neural network, multimodal data can be recorded by key semantic features related to the real scenarios. Then, we compress the semantic features using a graph transformer encoder at the transmitter, which can extract the semantic representations through the cross-modal attention mechanisms. Next, we leverage a graph semantic validation mechanism to guarantee the exactness of the overall data at the receiver. Furthermore, we adopt generative AI to regenerate multimodal data in virtual scenarios. Simultaneously, a novel 3D generative reconstruction network is constructed from the 3D point clouds, which can transfer the data from images to 3D models, and we infer the multimodal data into the 3D models to increase realism in virtual scenarios. Finally, the experiment results demonstrate that cross-modal graph semantic communication, assisted by generative AI, has substantial potential for enhancing user interactions in the 6G communications and Metaverse.

关键词： modal frontier guarantee

Task-Oriented Semantic Communication with Foundation Models

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China Communications 2024年第7期21卷 65-77页

作者： Chen mingkai Liu Minghao Zhang Zhe Xu Zhiping wang Lei Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China School of Ocean Information Engineering Jimei UniversityXiamen 361021China Key Laboratory of Underwater Acoustic Communication and Marine Information Technology(Xiamen University) Ministry EducationXiamen 361005China

In the future development direction of the sixth generation(6G)mobile communication,several communication models are proposed to face the growing challenges of the *** rapid development of artificial intelligence(AI)foundation models provides significant support for efficient and intelligent communication *** this paper,we propose an innovative semantic communication paradigm called task-oriented semantic communication system with foundation ***,we segment the image by using task prompts based on the segment anything model(SAM)and contrastive language-image pretraining(CLIP).Meanwhile,we adopt Bezier curve to enhance the mask to improve the segmentation ***,we have differentiated semantic compression and transmission approaches for segmented ***,we fuse different semantic information based on the conditional diffusion model to generate high-quality images that satisfy the users'specific task ***,the experimental results show that the proposed system compresses the semantic information effectively and improves the robustness of semantic communication.

关键词： diffusion model foundation model joint source-channel coding task-oriented semantic communication

Multimodal fusion recognition for digital twin

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Digital Communications and Networks 2024年第2期10卷 337-346页

作者： Tianzhe Zhou Xuguang Zhang Bing Kang mingkai Chen Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing210003China

The digital twin is the concept of transcending reality,which is the reverse feedback from the real physical space to the virtual digital *** hold great prospects for this emerging *** order to realize the upgrading of the digital twin industrial chain,it is urgent to introduce more modalities,such as vision,haptics,hearing and smell,into the virtual digital space,which assists physical entities and virtual objects in creating a closer ***,perceptual understanding and object recognition have become an urgent hot topic in the digital *** surface material classification schemes often achieve recognition through machine learning or deep learning in a single modality,ignoring the complementarity between multiple *** order to overcome this dilemma,we propose a multimodal fusion network in our article that combines two modalities,visual and haptic,for surface material *** the one hand,the network makes full use of the potential correlations between multiple modalities to deeply mine the modal semantics and complete the data *** the other hand,the network is extensible and can be used as a universal architecture to include more *** show that the constructed multimodal fusion network can achieve 99.42%classification accuracy while reducing complexity.

关键词： Digital twin Multimodal fusion Object recognition Deep learning Transfer learning