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A guidance and control design with reduced information for a dual-spin stabilized projectile

Defence Technology（防务技术） 2024年第3期33卷 494-505页

作者： yu Wang Jiyan yu Xiaoming Wang jia.Fangxiu Intelligent Ammunition Technology National Defense Key Discipline Laboratory Nanjing University of Science and TechnologyNanjingJiangsu210094China

In this paper,an integrated guidance and control method based on an adaptive path-following controller is proposed to control a spin-stabilized projectile with only translational motion information under the constraint of an actuator,uncertainties in aerodynamic parameters and measurements,and control system *** to the fairly high rotation speed,the dynamic model of this missile is strongly nonlinear,uncertain and coupled in pitch,yaw and roll cha.nels.A theoretical equivalent resultant force and uncertainty compensation method are comprehensively used to realize decoupling of pitch and *** response to the strong nonlinear and time-varying cha.acteristics of the dynamic system,the quasi-linear model whose parameters are obtained by interpolation of points selected as the segmentation points in the trajectory envelope,is used for calculation in each *** cope with the system uncertainty caused by model approximation,parameter uncertainty and ballistic interference,an extended state estimator is used to compensate the output feedback according to the test ballistic *** order to improve the tracking efficiency and ensure the tracking error convergence with only translational motion information,the virtual guide point,whose derivative is deduced according to the Lyapunov principle,is calculated in real time according to the projection relationship between the real-time position and the reference trajectory,and a virtual line-of-sight angle and the backstepping method are used for the design of the guidance and control *** order to avoid the influence of control input saturation on the guidance and control performance due to the actuator limitation and improve the robustness of the system,an anti-saturation compensator is designed according to the two-step *** feasibility and effectiveness of the path-following controller is verified through closed-loop flight simulations with measurement,control,and condition *** result

关键词： Spin-stabilized projectile Reduced information Path-following control Extended state observer Coupled nonlinear system Input saturation

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Large isolated fibrous tumors in the upper esopha.us: A case report

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World Journal of Gastrointestinal Oncology 2024年第2期16卷 543-549页

作者： jia.jia.yu Huan-Shuang Pei yu Meng Department of Anesthesiology The Fourth Hospital of Hebei Medical UniversityShijiazhuang 050000Hebei ProvinceChina

BACKGROUND Solitary fibrous tumors(SFT)are rare spindle cell tumors tha. are usually benign.A total of 10 cases of SFTs in the upper esopha.us ha.e ever been ***,we report the anesthetic management of a patient with a large isolated fibrous tumor of the upper esopha.us compressing the tracheal *** also provide a literature review of the current *** SUMMARY We report the case of a 49 year old male with“cough aggravation and wheezing after exercise”,who underwent esopha.ectomy for a large isolated fibrous tumor compressing the tracheal membrane in the upper *** advise the use of a single-lumen tube with a blocker in patients with difficult airways to reduce the incidence of airway injury and fibrinoscopy at all stages of the perioperative period to guide airway *** case study is the first report of the anesthetic management of a large,isolated fibrous tumor compressing the tracheal membrane in the upper *** This rare case empha.izes the importance of perioperative management of anesthesia in patients with large isolated fibrous tumors of the upper esopha.us tha. compress the tracheal *** use of blocker reduce the incidence of airway injury and fibrinoscopy at the perioperative period to guide airway mana-gement.

关键词： Upper esopha.us Isolated fibrous tumor Tracheal membrane Peak airway pressure Case report

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Towards imbalanced motion:part-decoupling network for video portrait segmentation

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Science China(Information Sciences) 2024年第7期67卷 197-210页

作者： Tianshu yu Cha.gqun XIA jia.LI State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and EngineeringBeihang University Peng Cheng Laboratory

Video portrait segmentation(VPS), aiming at segmenting prominent foreground portraits from video frames, ha. received much attention in recent years. However, the simplicity of existing VPS datasets leads to a limitation on extensive research of the task. In this work, we propose a new intricate large-scale multi-scene video portrait segmentation dataset MVPS consisting of 101 video clips in 7 scenario categories,in which 10843 sampled frames are finely annotated at the pixel level. The dataset ha. diverse scenes and complicated background environments, which is the most complex dataset in VPS to our best *** the observation of a large number of videos with portraits during dataset construction, we find tha. due to the joint structure of the human body, the motion of portraits is part-associated, which leads to the different parts being relatively independent in motion. Tha. is, the motion of different parts of the portraits is imbalanced. Towards this imbalance, an intuitive and reasonable idea is tha. different motion states in portraits can be better exploited by decoupling the portraits into parts. To achieve this, we propose a part-decoupling network(PDNet) for VPS. Specifically, an inter-frame part-discriminated attention(IPDA)module is proposed which unsupervisedly segments portrait into parts and utilizes different attentiveness on discriminative features specified to each different part. In this way, appropriate attention can be imposed on portrait parts with imbalanced motion to extract part-discriminated correlations, so tha. the portraits can be segmented more accurately. Experimental results demonstrate tha. our method achieves leading performance with the comparison to state-of-the-art methods.

关键词： video portrait segmentation imbalanced motion unsupervised part decoupling motion correlation inter-frame attention

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Diopha.tine equations and Fermat's last theorem for multivariate(skew-)polynomials

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 159-173页

作者： PAN Jie jia.yu-ming LI Fang School of Mathematical Sciences Zhejiang UniversityHangzhou 310058China Henan Experimental High School Zhengzhou 450003China

Fermat’s Last Theorem is a famous theorem in number theory which is diﬃcult to ***,it is known tha. the version of polynomials with one variable of Fermat’s Last Theorem over C can be proved very *** aim of this paper is to study the similar problems about Fermat’s Last Theorem for multivariate(skew)-polynomials with any cha.acteristic.

关键词： Fermat's last theorem polynomial ring skew polynomial ring

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Climatic impacts induced by winter wheat irrigation over North China simulated by the nonhydrostatic RegCM4.7

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Advances in Climate Cha.ge Research 2024年第2期15卷 197-210页

作者： jia.WU Zhen-yu ha. Xue-Jie GAO Zheng-jia.LIU National Climate Centre China Meteorological AdministrationBeijing 100081China Key Laboratory for Climate Studies China Meteorological AdministrationBeijing 100081China Climate Cha.ge Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China

Quantification of the impact of winter wheat irrigation on the climate and the occurrence of extreme climatic events over North China is crucial for regional adaptation *** related studies mainly focused on the impact on surface processes;however,few focused on the effects of extreme events using high-resolution nonhydrostatic regional climate ***,the 9-km-resolution nonhydrostatic RegCM4.7 was coupled with a crop irrigation scheme and an updated winter wheat irrigation dataset to better simulate irrigation *** experiments were conducted with and without winter wheat irrigation to isolate the effects of *** showed tha. irrigation simulation reduces the model biases in temperature,precipitation,latent heat flux,soil moisture,sensitive heat flux,and top-layer soil ***,it also reduces the bias and increases the correlation with observations obtained in irrigated areas,especially in summer,indicating better representation of irrigation *** wheat irrigation tends to cause substantial cooling of the local surface maximum,minimum,and mean air temperatures(by-1.68,-0.34,and-0.79℃,respectively)over irrigated areas of North China,with the largest cha.ges observed in relation to maximum ***,precipitation is found to increase during spring and summer,which is strongly related to water vapor transport in the lower levels of the *** analyses indicated tha. the number of annual mean hot days decrease(-13.9 d),whereas the number of both comfort days(+10.2 d)and rainy days(days with total precipitation greater tha. 1 mm:+6.6 d)increase over irrigated areas,demonstrating beneficial feedback to human perception and ***,although the heat wave risk increases(number of annual mean heat wave days:+5.8 d),the impact is limited to small areas within irrigated ***,no notable cha.ge was found in terms of heavy rainfall events and precipitation intensity

关键词： Nonhydrostatic regional climate model Irrigation effect Extreme events North China

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Network Intrusion Traffic Detection Based on Feature Extraction

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Computers, Materials & Continua 2024年第1期78卷 473-492页

作者： Xuecheng yu Yan Huang yu Zha.g Mingyang Song Zhenhong jia College of Information Science and Engineering Xinjiang UniversityUrumqi830046China Network Department China Mobile Communications Group Xinjiang CoLtd.UrumqiUrumqi830011China Xinjia.g Signal Detection and Processing Key Laboratory Xinjiang UniversityUrumqi830000China

With the increasing dimensionality of network traffic,extracting effective traffic features and improving the identification accuracy of different intrusion traffic ha.e become critical in intrusion detection systems(IDS).However,both unsupervised and semisupervised anomalous traffic detection methods suffer from the drawback of ignoring potential correlations between features,resulting in an analysis tha. is not an optimal ***,in order to extract more representative traffic features as well as to improve the accuracy of traffic identification,this paper proposes a feature dimensionality reduction method combining principal component analysis and Hotelling’s T^(2) and a multilayer convolutional bidirectional long short-term memory(MSC_BiLSTM)classifier model for network traffic intrusion *** method reduces the parameters and redundancy of the model by feature extraction and extracts the dependent features between the data by a bidirectional long short-term memory(BiLSTM)network,which fully considers the influence between the before and after *** network traffic is first cha.acteristically downscaled by principal component analysis(PCA),and then the downscaled principal components are used as input to Hotelling’s T^(2) to compare the differences between *** datasets with outliers,Hotelling’s T^(2) can help identify the groups where the outliers are located and quantitatively measure the extent of the ***,a multilayer convolutional neural network and a BiLSTM network are used to extract the spatial and temporal features of network traffic *** empirical consequences exhibit tha. the suggested approach in this manuscript attains superior outcomes in precision,recall and F1-score juxtaposed with the prevailing *** results show tha. the intrusion detection accuracy,precision,and F1-score of the proposed MSC_BiLSTM model for the CIC-IDS 2017 dataset are 98.71%,95.97%,and 90.22%.

关键词： Network intrusion traffic detection PCA Hotelling’s T^(2) BiLSTM

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On extended state Kalman filter-based identification algorithm for aerodynamic parameters

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Control Theory and Technology 2024年第2期22卷 235-243页

作者： Wenyan Bai Ruizhe jia.Peng yu Wencha. Xue Beijing Aerospace Automatic Control Institute Beijing100854China School of Automation and Electrical Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of Knowledge Automation for Industrial Processes Ministry of EducationBeijing100083China Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing100190China

In this paper, the problem of time-varying aerodynamic parameters identification under measurement noises is studied. By analyzing the key aerodynamic parameters tha. affect the aircraft control system, a system model with extended states for identifying equivalent aerodynamic parameters is established, and error parameters are extended to the system state, avoiding the difficulty caused by the unknown dynamic in the system. Furthermore, an identification algorithm based on extended state Kalman filter is designed, and it is proved tha. the algorithm ha. quasi-consistency, thus, the estimation error can be evaluated in real time. Finally, the simulation results under typical flight scenarios show tha. the designed algorithm can accurately identify aerodynamic parameters, and ha. desired convergence speed and convergence precision.

关键词： Aerodynamic parameters Parameter identification Extended state Kalman filter

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Structure engineering of cathode host materials for Li-S batteries

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Rare Metals 2024年第4期43卷 1370-1389页

作者： jia.Jun Long Hua yu Wen-Bo Liu School of New Energy and Materials Southwest Petroleum UniversityChengdu610500China School of Mecha.ical Engineering Sichuan UniversityChengdu610065China

Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key cha.lenges tha. ha.e not been addressed ha.e limited its *** cha.lenges include lithium dendrite growth in the anode side,volume cha.ge of the active material,poor electrical conductivity,dissolution and migration of poly sulfides,and slow rate of solid-state reactions in the cathode *** the electrochemical performance of lithium-sulfur batteries is greatly affected by the design of the cathode host material,it ha. also been widely discussed in addressing the abovementioned *** this paper,three design ideas of cathode host materials in terms of microstructure,crystal structure and electronic structure are introduced and ***,the current progress of these three structural design strategies and their effects on the electrochemical performance of lithium-sulfur batteries are discussed in ***,future directions in the structural design of cathode materials for lithium-sulfur batteries are discussed and further perspectives are provided.

关键词： Lithium-sulfur batteries Structure engineering Cathode Host materials

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Optimized parameters of downhole all-metal PDM based on genetic algorithm

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Petroleum Science 2024年第4期21卷 2663-2676页

作者： jia.Xing Lu Ling-Rong Kong yu Wang Cha. Feng yu-Lin Gao China University of Geosciences (Beijing) Key Laboratory on Deep Geo-Drilling Technology of Ministry of Natural Resources

Currently, deep drilling operates under extreme conditions of high temperature and high pressure,demanding more from subterranean power motors. The all-metal positive displacement motor, known for its robust performance, is a critical choice for such drilling. The dimensions of the PDM are crucial for its performance output. To enha.ce this, optimization of the motor's profile using a genetic algorithm ha. been undertaken. The design process begins with the computation of the initial stator and rotor curves based on the equations for a screw cycloid. These curves are then refined using the least squares method for a precise fit. Following this, the PDM's mathematical model is optimized, and motor friction is assessed. The genetic algorithm process involves encoding variations and managing crossovers to optimize objective functions, including the isometric radius coefficient, eccentricity distance parameter,overflow area, and maximum slip speed. This optimization yields the ideal profile parameters tha. enha.ce the motor's output. Comparative analyses of the initial and optimized output cha.acteristics were conducted, focusing on the effects of the isometric radius coefficient and overflow area on the motor's performance. Results indicate tha. the optimized motor's overflow area increased by 6.9%, while its rotational speed reduced by 6.58%. The torque, as tested by Infocus, saw substantial improvements of38.8%. This optimization provides a theoretical foundation for improving the output cha.acteristics of allmetal PDMs and supports the ongoing development and research of PDM technology.

关键词： Positive displacement motor Genetic algorithm Profile optimization Matlab programming Overflow area

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Advances of graphdiyne-supported metal catalysts in thermocatalytic reactions

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Nano Research 2024年第4期17卷 2223-2233页

作者： jia.yu Yida Yang yuliang Li Cha.gyan Cao Weiguo Song Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular SciencesLaboratory of Molecular Nanostructures and NanotechnologyInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular SciencesLaboratory of organic solidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

Supported metal catalysts are widely used in the modern chemical *** electronic interaction between supports and active components is of great significance for heterogeneous ***(GDY),a new type of carbon allotrope with sp-hybridized carbon atoms,πconjugate structure,and electron transmission capability,is a promising candidate as catalyst *** years ha.e witnessed the rapid progress of GDY-supported metal catalysts for different catalysis *** tha. most processes in the current chemical industry are thermocatalytic reactions,we herein give an overview about the advances and particular cha.acteristics of GDY-supported catalysts in these *** geometric structure and electronic properties of GDY are first ***,the synthesis methods for GDY-supported metal catalysts and their applications in thermocatalytic reactions are discussed,in which the effect of electronic interaction on catalytic performance is ***,the current cha.lenges and future directions of GDY-supported metal catalysts for thermocatalysis are *** is expected tha. this review will enrich our understanding of the advances of GDY as a superior support for metal catalysts in thermocatalytic reactions.

关键词： graphdiyne metal catalysts thermocatalytic reactions heterogeneous catalysis

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