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Pseudospectral method based trajectory optimization and fairing rejection time analysis of solid launch vehicle

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Science China(Technological Sciences) 2009年第11期52卷 3198-3206页

作者： XUAN Ying zhang WeiHua zhang yulin College of Aerospace and Material Engineering National University of Defense TechnologyChangsha 410073China

The problem of real-time trajectory optimization for small solid launch vehicle of operational responsive space (ORS) was studied by using pseudospectral method. According to the characteristic of the trajectory design, the dynamics model was set up in the inertia right-angled reference frame, and the equation and parameter at the orbit injection point were simplified and converted. The infinite dimension dynamic optimal control problem was converted to a finite dimension static state optimization problem and the algorithm reduced the complexity so as to become a general algorithm in trajectories optimization. With the trajectories optimization of a three-stage solid vehicle with a liquor upper stage as example, the model of the trajectory optimization was set up and simulations were carried out. The results demonstrated the advantage and validity of the pseudospectral method. The rejection time of fairing was also analyzed by the simulation results, and the optimal flight procedure and trajectory were obtained.

关键词： pseudospectral method solid launch vehicle trajectory optimization rejection time of fairing

Multi-agent decision support system for missile defense based on improved PSO algorithm

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Journal of Systems Engineering and Electronics 2017年第3期28卷 514-525页

作者： Zilong Cheng Li Fan yulin zhang College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China Academy of Equipment Beijing 101416China

Ballistic missile defense system (BMDS) is important for its special role in ensuring national security and maintaining strategic balance. Research on modeling and simulation of the BMDS beforehand is essential as developing a real one requires lots of manpower and resources. BMDS is a typical complex system for its nonlinear, adaptive and uncertainty characteristics. The agent-based modeling method is well suited for the complex system whose overall behaviors are determined by interactions among individual elements. A multi-agent decision support system (DSS), which includes missile agent, radar agent and command center agent, is established based on the studies of structure and function of BMDS. Considering the constraints brought by radar, intercept missile, offensive missile and commander, the objective function of DSS is established. In order to dynamically generate the optimal interception plan, the variable neighborhood negative selection particle swarm optimization (VNNSPSO) algorithm is proposed to support the decision making of DSS. The proposed algorithm is compared with the standard PSO, constriction factor PSO (CFPSO), inertia weight linear decrease PSO (LDPSO), variable neighborhood PSO (VNPSO) algorithm from the aspects of convergence rate, iteration number, average fitness value and standard deviation. The simulation results verify the efficiency of the proposed algorithm. The multi-agent DSS is developed through the Repast simulation platform and the constructed DSS can generate intercept plans automatically and support three-dimensional dynamic display of missile defense process.

关键词： agent-based modeling missile defense system decision support system (DSS) variable neighborhood negative selection particle swarm optimization (PSO)

A framework for equipment systems-of-systems effectiveness evaluation using parallel experiments approach

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Journal of Systems Engineering and Electronics 2015年第2期26卷 292-300页

作者： Zilong Cheng Li Fan yulin zhang College of Aerospace Science and Engineering National University of Defense Technology Academy of Equipment

Equipment systems-of-systems （SOS） effectiveness evaluation can provide important reference for construction and optimization of the equipment SoS. After discussing the basic theory and methods of parallel experiments, we depict an SoS effectiveness analysis and evaluation method using parallel expe- riments theory in detail. A case study is carried out which takes the missile defense system as an example. An artificial system of the missile defense system is constructed with the multi-agent modeling method. Then, single factor, multiple factors and defense position deployment computational experiments are carried out and evaluated with the statistical analysis method. Experiment re- sults show that the altitude of the secondary interception missile is not the key factor which affects SoS effectiveness and putting the defense position ahead will increase defense effectiveness. The case study demonstrates the feasibility of the proposed method.

关键词： agent based modeling parallel experiments computational experiments missile defense system effectiveness evaluation

THE RECONSTRUCTION OF AN HERMITIAN TOEPLITZ MATRIX WITH PRESCRIBED EIGENPAIRS

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Journal of Systems Science & Complexity 2010年第5期23卷 961-970页

作者： Zhongyun LIU Lu CHEN yulin zhang School of Mathematics and Computing Science Changsha University of Science and Technology Changsha 410076 China Department of Mathematics University of Minho Campus de Gualtar 4710-057 Braga Portugal

This paper concerns the reconstruction of an hermitian Toeplitz matrix with prescribed eigenpairs. Based on the fact that every centrohermitian matrix can be reduced to a real matrix by a simple similarity transformation, the authors first consider the eigenstructure of hermitian Toeplitz matrices and then discuss a related reconstruction problem. The authors show that the dimension of the subspace of hermitian Toeplitz matrices with two given eigenvectors is at least two and independent of the size of the matrix, and the solution of the reconstruction problem of an hermitian Toeplitz matrix with two given eigenpairs is unique.

关键词： Centrohermitian matrix hermitian Toeplitz matrix inverse eigenproblems reconstruction.

Coupled modeling and analysis of radiometer effect and residual gas damping on proof mass in purely gravitational orbit

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Science China(Technological Sciences) 2011年第4期54卷 894-902页

作者： LIU HongWei WANG ZhaoKui zhang yulin Institute of Aerospace and Material Engineering National University of Defense TechnologyChangsha 410073China School of Aerospace Tsinghua UniversityBeijing 100084China

Spacecrafts free of all but gravitational forces are important in precision navigation,gravity field measurement and basic scientific *** Inner-formation Flying System,one kind of spacecrafts free of all but gravitational forces,is used for gravitational field measurement with high *** the interfering factors on the inner-satellite is one of the keys to gravitational field *** effect and residual gas damping are both interfering forces on the inner-satellite caused by gas *** analyzing the mechanism of the two forces,a coupled model for radiometer effect and residual gas damping was established,which contained the coupling term and reflected the actual force of gas molecules on the *** simulation results showed the coupling property of radiometer effect and residual gas damping:The actual force of gas molecules is directly proportional to the average pressure in the cavity and the largest cross-sectional area of the inner-satellite,but is inversely proportional to the square root of the average temperature in the cavity.

关键词： purely gravitational orbit proof mass radiometer effect residual gas damping coupled modeling

Gradient-based Kriging approximate model and its application research to optimization design

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Science China(Technological Sciences) 2009年第4期52卷 1117-1124页

作者： XUAN Ying XIANG JunHua zhang WeiHua zhang yulin College of Aerospace and Material Engineering National University of Defense TechnologyChangsha 410073China

In the process of multidisciplinary design optimization, there exits the calculation complexity problem due to frequently calling high fidelity system analysis models. The high fidelity system analysis models can be surrogated by approximate models. The sensitivity analysis and numerical noise filtering can be done easily by coupling approximate models to optimization. Approximate models can reduce the number of executions of the problem's simulation code during optimization, so the solution efficiency of the multidisciplinary design optimization problem can be improved. Most optimization methods are based on gradient. The gradients of the objective and constrain functions are gained easily. The gra- dient-based Kriging (GBK) approximate model can be constructed by using system response value and its gradients. The gradients can greatly improve prediction precision of system response. The hybrid optimization method is constructed by coupling GBK approximate models to gradient-based optimiza- tion methods. An aircraft aerodynamics shape optimization design example indicates that the methods of this paper can achieve good feasibility and validity.

关键词： Kriging approximation function gradient-based approximate model hybrid optimization method multidisciplinary design optimization

Tumor Classification of Gene Expression Data by Fuzzy Hybrid Twin SVM

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Chinese Journal of Electronics 2022年第1期31卷 99-106页

作者： DUAN Hua FENG Tong LIU Songning zhang yulin SU Jionglong College of Mathematics and Systems Science Shandong University of Science and Technology School of AI and Advanced Computing XJTLU Entrepreneur College (Taicang) Xi'an Jiaotong-Liverpool University

A new classification model, the fuzzy hybrid twin support vector machine(TWSVM), namely FHTWSVM, is proposed by combining the fuzzy TWSVM and the hypersphere support vector machine(SVM).The hypersphere SVM is utilized for generating the hyperspheres for the positive and negative class with the smallest possible radius, so that the hyperspheres can contain as many samples as possible. The samples which the hyperspheres cover form a new sample set. Furthermore a distance-based fuzzy function is utilized to calculate the fuzzy factors for the samples. Finally FHTWSVM is used to train all samples with the parameters optimized by grid search. This method can maximize intra-class clustering for noise removal and reduce the influence of *** demonstrate the superiority of the performance of FHTWSVM over other classifiers, e.g., KNN, RF,Bayesian, TWSVM, Ada Boost and XGBoost, a series of experiments is conducted using eight gene expression datasets. The evaluation results show that the proposed approach can improve the classification performance as well as reduce prediction errors for the datasets.

关键词： biology computing support vector machines grid search fuzzy TWSVM hypersphere support vector machine hypersphere SVM intra-class clustering pattern classification fuzzy hybrid twin SVM FHTWSVM tumor classification tumours fuzzy hybrid twin support vector machine learning (artificial intelligence) distance-based fuzzy function fuzzy set theory pattern clustering search problems gene expression data

Rockburst prediction and prevention in underground space excavation

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Underground Space 2024年第1期14卷 70-98页

作者： Jian Zhou yulin zhang Chuanqi Li Haini He Xibing Li School of Resources and Safety Engineering Central South UniversityChangsha 410083China Laboratory 3SR CNRS UMR 5521Grenoble Alpes UniversityGrenoble 38000France

The technical challenges associated with deep underground space activities have become increasingly *** these challenges,one major concern is the assessment of rockburst risks and the instability of rock *** research has been conducted by numerous scholars to mitigate the risks and prevent occurrences of rockburst through various assessment *** incidents commonly occur during the excavation of hard rock in underground environments,posing severe threats to personnel safety,equipment integrity,and operational ***,it is crucial to systematically document real cases of rockburst,allowing for a comprehensive understanding of the underlying mechanisms and triggering *** understanding will contribute to the advancement of rockburst prediction and prevention *** selection of an appropriate rockburst assessment method is a fundamental aspect in underground ***,there is a limited number of studies that summarize and compare different prediction and prevention methods of *** paper aims to address this gap by analyzing global trends using CiteSpace software since *** discusses rockburst classification and characteristics,comprehensively reviews research findings related to rockburst prediction,including empirical,simulation,mathematical modeling,and microseismic monitoring ***,the paper presents a compilation of current rockburst prevention ***,the paper emphasizes the significance of control strategies,which provide key insights into the effective utilization of stored energy within ***,the paper concludes by suggesting six directions for implementing intelligent management techniques to mitigate hazards during underground operations and reduce the probability of rockburst incidents.

关键词： Rockburst Underground space Scientometric analysis Characteristic analysis Rockburst prediction Rockburst prevention

Sexual Dimorphism of Inputs to the Lateral Habenula in Mice

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Neuroscience Bulletin 2022年第12期38卷 1439-1456页

作者： Xue Liu Hongren Huang yulin zhang Liping Wang Feng Wang Shenzhen Key Lab of Neuropsychiatric Modulation Guangdong Provincial Key Laboratory of Brain Connectome and BehaviorCAS Key Laboratory of Brain Connectome and Manipulationthe Brain Cognition and Brain Disease InstituteShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research InstitutionsShenzhen 518055China University of the Chinese Academy of Sciences Beijing 100049China

The lateral habenula(LHb),which is a critical neuroanatomical hub and a regulator of midbrain monoaminergic centers,is activated by events resulting in negative valence and contributes to the expression of both appetitive and aversive ***,whole-brain cell-type-specific monosynaptic inputs to the LHb in both sexes remain incompletely *** this study,we used viral tracing combined with in situ hybridization targeting vesicular glutamate transporter 2(vGlut2)and glutamic acid decarboxylase 2(Gad2)to generate a comprehensive whole-brain atlas of inputs to glutamatergic andγ-aminobutyric acid(GABA)ergic neurons in the *** found>30 ipsilateral and contralateral brain regions that projected to the *** these,there were significantly more monosynaptic LHb-projecting neurons from the lateral septum,anterior hypothalamus,dorsomedial hypothalamus,and ventromedial hypothalamus in females than in *** interestingly,we found a stronger GABAergic projection from the medial septum to the LHb in males than in *** results reveal a comprehensive connectivity atlas of glutamatergic and GABAergic inputs to the LHb in both sexes,which may facilitate a better understanding of sexual dimorphism in physiological and pathological brain functions.

关键词： vGlut2 Gad2 Monosynaptic inputs Lateral habenula Sex differences Rabies retrograde tracing