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INVEsTIGATIONs　ON　THE　FORMATION　OF　INITIAL　CRACks　IN　THERMAL　BARRIER　COATINGs　PREPARED　BY　EB－PVD

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Acta Metallurgica sinica(English Letters) 1996年第6期9卷 519-522页

作者： s.k.gong L. Deng F.s.Liu and H.B.Xu(Department of Material science and Engineering,Beijing University of Aeronautics and Astronautics,Beijing 100083,China ) Beijing Univ of Aeronautics and Astronautics Beijing China

This paper deals with the mechanism of the formation of initial cracks in the yttria partially stabilized zirconia thermal barrier coatings prepared by EB-PVD *** microcracks were only recognized inside the ceramic top coat of the thermalcycled TBCs. sEM/EDs observations indicated that some special oxides exist in the area just below the *** seems that the formation of the initial cracks can result from the oxidation stress as well as the thermal stress.

关键词： TBCs EB-PVD thermocycle initial cracks

sparse Reconstructive Evidential Clustering for Multi-View Data

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IEEE/CAA Journal of Automatica sinica 2024年第2期11卷 459-473页

作者： Chaoyu gong Yang You school of Computing National University of SingaporeSingapore

Although many multi-view clustering(MVC) algorithms with acceptable performances have been presented, to the best of our knowledge, nearly all of them need to be fed with the correct number of clusters. In addition, these existing algorithms create only the hard and fuzzy partitions for multi-view objects,which are often located in highly-overlapping areas of multi-view feature space. The adoption of hard and fuzzy partition ignores the ambiguity and uncertainty in the assignment of objects, likely leading to performance degradation. To address these issues, we propose a novel sparse reconstructive multi-view evidential clustering algorithm(sRMVEC). Based on a sparse reconstructive procedure, sRMVEC learns a shared affinity matrix across views, and maps multi-view objects to a 2-dimensional humanreadable chart by calculating 2 newly defined mathematical metrics for each object. From this chart, users can detect the number of clusters and select several objects existing in the dataset as cluster centers. Then, sRMVEC derives a credal partition under the framework of evidence theory, improving the fault tolerance of clustering. Ablation studies show the benefits of adopting the sparse reconstructive procedure and evidence theory. Besides,sRMVEC delivers effectiveness on benchmark datasets by outperforming some state-of-the-art methods.

关键词： Evidence theory multi-view clustering(MVC) optimization sparse reconstruction

Tropical cyclone genesis over the western north Pacific in La Ni?a decay summers: Comparison between 2018 and 2021

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science China Earth sciences 2024年第10期67卷 3098-3109页

作者： Yunyun LIU Zhensong gong China Meteorological Administration key Laboratory for Climate Prediction studies National Climate CentreBeijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China

As the primary interannual signal of variability in the tropical ocean-atmosphere interaction, the El Ni?o-southern Oscillation has a considerable impact on tropical cyclone(TC) activity over the western North Pacific(WNP). Both 2018 and2021 were La Ni?a decay years, but TC activity over the WNP during the two summers(June–August) showed notable differences. In 2018, summer TC activity was unusually high with a total of 18 TCs, and the region of TC genesis was mainly in the central and eastern WNP. In contrast, only 9 TCs were generated in summer 2021, and the region of TC genesis was primarily in the western WNP. By comparing the characteristics of the large-scale environmental conditions over the regions of TC genesis, the thermal factors of the tropical oceans, and the activity of the Madden-Julian Oscillation(MJO), this study revealed the possible causes for the marked differences in TC genesis over the WNP during the two summers, which both had a similar background of La Ni?a decay. The Indian Ocean Basin Mode(IOBM) transitioned of a cold anomaly in the winter of 2017/2018and persisted until summer 2018. At the same time, the Pacific Meridional Mode(PMM) maintained a positive phase, leading to eastward and northward displacement of the Western Pacific subtropical High in summer, and eastward extension of the tropical monsoon trough, which presented conditions conducive to TC genesis over the Northwest Pacific. Moreover, the days when the MJO stagnated in phases 5 and 6 in the summer of 2018 increased by approximately 150% relative to climatological state,providing dynamic conditions favorable for TC formation. In 2021, the IOBM quickly turned to a warm anomaly in March and persisted until summer, whereas the PMM became a negative phase in January and remained so until summer. At the same time,the MJO stagnated in phases 2 and 3 for up to 47 days, with the center of convection located over the western Maritime Continent, producing conditions unconducive to TC ge

关键词： Tropical cyclone La Nina events Indian Ocean Basin Mode Pacific Meridional Mode Madden-Julian Oscillation Western Pacific subtropical High Monsoon trough

Exploring a Promising Region and Enhancing Decision space Diversity for Multimodal Multi-Objective Optimization

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Tsinghua science and Technology 2024年第2期29卷 325-342页

作者： Fei Ming Wenyin gong school of Computer science China University of GeosciencesWuhan 430074China

During the past decade,research efforts have been gradually directed to the widely existing yet less noticed multimodal multi-objective optimization problems(MMOPs)in the multi-objective optimization ***,researchers have begun to investigate enhancing the decision space diversity and preserving valuable dominated solutions to overcome the shortage caused by a preference for objective space ***,many existing methods still have limitations,such as giving unduly high priorities to convergence and insufficient ability to enhance decision space *** overcome these shortcomings,this article aims to explore a promising region(PR)and enhance the decision space diversity for handling *** traditional methods,we propose the use of non-dominated solutions to determine a limited region in the PR in the decision space,where the Pareto sets(Pss)are included,and explore this region to assist in solving ***,we develop a novel neighbor distance measure that is more suitable for the complex geometry of Pss in the decision space than the crowding *** on the above methods,we propose a novel dual-population-based coevolutionary *** studies on three benchmark test suites demonstrates that our proposed methods can achieve promising performance and versatility on different *** effectiveness of the proposed neighbor distance has also been justified through comparisons with crowding distance methods.

关键词： multimodal multi-objective optimization evolutionary algorithms promising region neighbor distance decision space coevolution

BLs-identification:A device fingerprint classification mechanism based on broad learning for Internet of Things

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Digital Communications and Networks 2024年第3期10卷 728-739页

作者： Yu Zhang Bei gong Qian Wang Faculty of Information Technology Beijing University of TechnologyBeijing100124China school of Information science and Technology Zhengzhou Normal UniversityHenan450044China

The popularity of the Internet of Things(IoT)has enabled a large number of vulnerable devices to connect to the Internet,bringing huge security *** a network-level security authentication method,device fingerprint based on machine learning has attracted considerable attention because it can detect vulnerable devices in complex and heterogeneous access ***,flexible and diversified IoT devices with limited resources increase dif-ficulty of the device fingerprint authentication method executed in IoT,because it needs to retrain the model network to deal with incremental features or *** address this problem,a device fingerprinting mechanism based on a Broad Learning system(BLs)is proposed in this *** mechanism firstly characterizes IoT devices by traffic analysis based on the identifiable differences of the traffic data of IoT devices,and extracts feature parameters of the traffic packets.A hierarchical hybrid sampling method is designed at the preprocessing phase to improve the imbalanced data distribution and reconstruct the fingerprint *** complexity of the dataset is reduced using Principal Component Analysis(PCA)and the device type is identified by training weights using *** experimental results show that the proposed method can achieve state-of-the-art accuracy and spend less training time than other existing methods.

关键词： Device fingerprint Traffic analysis Class imbalance Broad learning system Access authentication

Phase-modulated multi-foci microscopy for rapid 3D imaging

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Photonics Research 2024年第7期12卷 1548-1555页

作者： WEIQI WANG LI gong ZHIWEI HUANG Optical Bioimaging Laboratory Department of Biomedical EngineeringCollege of Design and EngineeringNational University of SingaporeSingapore 117576Singapore

3D imaging technology is pivotal in monitoring the functional dynamics and morphological alterations in living cells and ***,conventional volumetric imaging associated with mechanical z-scanning encounters challenges in limited 3D imaging speed with inertial ***,we present a unique phase-modulated multifoci microscopy (PM^(3)) technique to achieve snapshot 3D imaging with the advantages of extended imaging depths and adjustable imaging intervals between each focus in a rapid *** accomplish the tasks,we utilize a spatial light modulator (sLM) to encode the phases of the scattered or fluorescence light emanating from a volumetric sample and then project the multiple-depth images of the sample onto a single charge-coupled device camera for rapid 3D *** demonstrate that the PM^(3)technique provides~55-fold improvement in imaging depth in polystyrene beads phantom compared to the depth of field of the objective lens ***^(3)also enables the real-time monitoring of Brownian motion of fluorescent beads in water at a 15 Hz volume *** precisely manipulating the phase of scattered light on the sLM,PM^(3)can pinpoint the specific depth information in living zebrafish and rapidly observe the 3D dynamic processes of blood flow in the zebrafish *** work shows that the PM^(3)technique developed is robust and versatile for fast 3D dynamic imaging in biological and biomedical systems.

关键词： alterations scattered beads

Time-of-flight resolved stimulated Raman scattering microscopy using counter-propagating ultraslow Bessel light bullets generation

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Light(science & Applications) 2024年第7期13卷 1427-1440页

作者： shulang Lin Li gong Zhiwei Huang Optical Bioimaging Laboratory Department of Biomedical EngineeringCollege of Design and EngineeringNational University of SingaporeSingapore 117576Singapore

We present a novel time-of-flight resolved Bessel light bullet-enabled stimulated Raman scattering(B2-sRs)microscopy for deeper tissue 3D chemical imaging with high resolution without a need for mechanical *** accomplish the tasks,we conceive a unique method to enable optical sectioning by generating the counterpropagating pump and stokes Bessel light bullets in the sample,in which the group velocities of the Bessel light bullets are made ultraslow(e.g.,vg≈0.1c)and tunable by introducing programmable angular dispersions with a spatial light *** theoretically analyze the working principle of the collinear multicolor Bessel light bullet generations and velocity controls with the relative time-of-flight resolved detection for sRs 3D deep tissue *** have also built the B2-sRs imaging system and present the first demonstration of B2-sRs microscopy with Bessel light bullets for 3D chemical imaging in a variety of samples(e.g.,polymer bead phantoms,biological samples such as spring onion tissue and porcine brain)with high *** B2-sRs technique provides a>2-fold improvement in imaging depth in porcine brain tissue compared to conventional sRs *** method of optical sectioning in tissue using counter-propagating ultraslow Bessel light bullets developed in B2-sRs is generic and easy to perform and can be readily extended to other nonlinear optical imaging modalities to advance 3D microscopic imaging in biological and biomedical systems and beyond.

关键词： Bessel resolved propagating

Even search in a Promising Region for Constrained Multi-Objective Optimization

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IEEE/CAA Journal of Automatica sinica 2024年第2期11卷 474-486页

作者： Fei Ming Wenyin gong Yaochu Jin school of Computer science China University of GeosciencesWuhan 430074China IEEE Faculty of Technology Bielefeld UniversityNorth Rhine-Westphalia 33619Germany school of Engineering Westlake UniversityHangzhou 310030China

In recent years, a large number of approaches to constrained multi-objective optimization problems(CMOPs) have been proposed, focusing on developing tweaked strategies and techniques for handling constraints. However, an overly finetuned strategy or technique might overfit some problem types,resulting in a lack of versatility. In this article, we propose a generic search strategy that performs an even search in a promising region. The promising region, determined by obtained feasible non-dominated solutions, possesses two general ***, the constrained Pareto front(CPF) is included in the promising region. second, as the number of feasible solutions increases or the convergence performance(i.e., approximation to the CPF) of these solutions improves, the promising region shrinks. Then we develop a new strategy named even search,which utilizes the non-dominated solutions to accelerate convergence and escape from local optima, and the feasible solutions under a constraint relaxation condition to exploit and detect feasible regions. Finally, a diversity measure is adopted to make sure that the individuals in the population evenly cover the valuable areas in the promising region. Experimental results on 45 instances from four benchmark test suites and 14 real-world CMOPs have demonstrated that searching evenly in the promising region can achieve competitive performance and excellent versatility compared to 11 most state-of-the-art methods tailored for CMOPs.

关键词： Constrained multi-objective optimization even search evolutionary algorithms promising region real-world problems

secure Tracking Control via Fixed-Time Convergent Reinforcement Learning for a UAV CPs

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IEEE/CAA Journal of Automatica sinica 2024年第7期11卷 1699-1701页

作者： Zhenyu gong Feisheng Yang the school of Automation Northwestern Polytechnical UniversityXi’an 710129 the Research&Development Institute of Northwestern Polytechnical University in shenzhen Shenzhen 518063China

Dear Editor,This letter is concerned with the secure tracking control problem in the unmanned aerial vehicle(UAV) system by fixed-time convergent reinforcement learning(RL). By virtue of the zero-sum game,the false da... 详细信息

关键词： secure Fixed false