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Capurability analysis for arbitrarily high-speed maneuvering targets

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Chinese Journal of Aeronautics 2023年第10期36卷 375-390页

作者： Shaobo wang Yang GUO shicheng wang Lixin wang Yanhua TAO Zhengfei PENG Xi’an Research Institution of Hi-Technology Xi’an 710025China Xi’an Satellite Control Center Xi’an 710043China

The capturability of an arbitrarily maneuvering target featuring speed superiority over an interceptor is analyzed for Augmented Pure Proportional Navigation(APPN)and RetroAugmented Proportional Navigation(RAPN)*** paper focuses on intercepting arbitrary maneuvers to study more general interception problems.A comparative analysis of the capture region between head-on interception related to APPN and head-pursuit interception related to RAPN is *** results indicate that RAPN performs better than APPN in *** is concluded that increasing the target velocity,which increases the velocity ratio,significantly weakens the capturability of the interceptor,and the average acceleration and relative distance affect the location of the capture region but not its *** analysis is based on prior knowledge of the target maneuver,which inevitably leads to deviations from actual maneuvers in practical engagement,so a deviation analysis is *** effective capture region shrinks as the absolute value of acceleration deviation increases,and the RAPN has a better deviation fault tolerance compared with the *** results reveal that a larger relative distance can weaken the deviation fault tolerance,and the target velocity has opposite effects on head-on and head-pursuit interception.

关键词： Acceleration deviation Arbitrarily maneuvering Capturability High-speed targets Retro-augmented pure proportional navigation

Embedding Periodic Maps on Surfaces into Those on S^3

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Chinese Annals of Mathematics,Series B 2015年第2期36卷 161-180页

作者： Yu GUO Chao wang shicheng wang Yimu ZHANG School of Mathematical Sciences Peking University

Call a periodic map h on the closed orientable surface Σg extendable if h extends to a periodic map over the pair(S3, Σg) for possible embeddings e : Σg→ S3. The authors determine the extendabilities for all periodical maps on Σ2. The results involve various orientation preserving/reversing behalves of the periodical maps on the pair(S3, Σg). To do this the authors first list all periodic maps on Σ2, and indeed the authors exhibit each of them as a composition of primary and explicit symmetries, like rotations, reflections and antipodal maps, which itself should be interesting. A by-product is that for each even g,the maximum order periodic map on Σg is extendable, which contrasts sharply with the situation in the orientation preserving category.

关键词： Symmetry of surface Symmetry of 3-sphere Extendable action

Embedding compact surfaces into the 3-dimensional Euclidean space with maximum symmetry

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Science China Mathematics 2017年第9期60卷 1599-1614页

作者： wang Chao wang shicheng ZHANG YiMu ZIMMERMANN Bruno Jonsvannsveien 87B H0201Trondheim 7050Noway School of Mathematical Sciences Peking UniversityBeijing 100871China Mathematics School Jilin UniversityChangehun 130012China Dipartimento di Matematica e Geoseienze Universita degli Studi di TriesteTrieste 34100Italy

The symmetries of surfaces which can be embedded into the symmetries of the 3-dimensional Euclidean space R3 are easier to feel by human＇s intuition. We give the maximum order of finite group actions on （R3 E） among all possible embedded closed/bordered surfaces with given geometric/algebraic genus greater than 1 in R3. We also identify the topological types of the bordered surfaces realizing the maximum order, and findsimple representative embeddings for such surfaces.

关键词： finite group action extendable action symmetry of surface maximum order

Detection of Multivariate Geochemical Anomalies Using the Bat-Optimized Isolation Forest and Bat-Optimized Elliptic Envelope Models

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Journal of Earth Science 2021年第2期32卷 415-426页

作者： Yongliang Chen shicheng wang Qingying Zhao Guosheng Sun College of Earth Sciences Jilin UniversityChangchun 130061China Institute of Mineral Resources Prognosis on Synthetic Information Jilin UniversityChangchun 130026China

Isolation forest and elliptic envelope are used to detect geochemical anomalies,and the bat algorithm was adopted to optimize the parameters of the two *** two bat-optimized models and their default-parameter counterparts were used to detect multivariate geochemical anomalies from the stream sediment survey data of 1:50000 scale collected from the Helong district,Jilin Province,*** on the data modeling results,the receiver operating characteristic(ROC)curve analysis was performed to evaluate the performance of the two bat-optimized models and their default-parameter *** results show that the bat algorithm can improve the performance of the two models by optimizing their parameters in geochemical anomaly *** optimal threshold determined by the Youden index was used to identify geochemical anomalies from the geochemical data *** with the anomalies detected by the elliptic envelope models,the anomalies detected by the isolation forest models have higher spatial relationship with the mineral occurrences discovered in the study *** to the results of this study and previous work,it can be inferred that the background population of the study area is complex,which is not suitable for the establishment of elliptic envelope model.

关键词： bat algorithm isolation forest elliptic envelope receiver operating characteristic curve analysis geochemical anomaly detection

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Simultaneous estimation of ego-motion and vehicle distance by using a monocular camera

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Science China(Information Sciences) 2014年第5期57卷 272-281页

作者： YANG DongFang SUN FuChun wang shicheng ZHANG JinSheng The Second Artillery Engineering University State Key Laboratory of Intelligent Technology and Systems Tsinghua University

Auto navigation and vehicle distance estimation are of the critical importance in intelligent *** paper proposes a novel approach to solve these two problems simultaneously by using a monocular ***,we introduce an incremental depth parameterized model to overcome the scale ambiguity problem in monocular vision,which differs from other parameterized models with reduced state-dimension and consistent *** addition,the view-field of camera is divided into static and dynamic parts so that the egomotion and vehicle-space can be calculated *** experiments are implemented to validate the effectiveness of the proposed approach.

关键词： auto navigation monocular vision vehicle distance

Distributed Containment Control of Networked Nonlinear Second-order Systems With Unknown Parameters

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IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 232-239页

作者： Long Ma Haibo Min shicheng wang Yuan Liu Zhiguo Liu Unit 96630 of PLA Beijing 102206 China High-tech Institute of Xi'an Xi'an 710025 China

In this paper, we study the containment control problem for nonlinear second-order systems with unknown parameters and multiple stationary/dynamic leaders. The topologies that characterize the interaction among the leaders and the followers are directed graphs. Necessary and sufficient criteria which guarantee the control objectives are established for both stationary leaders(regulation case) and dynamic leaders(dynamic tracking case) based protocols. The final states of all the followers are exclusively determined by the initial values of the leaders and the topology structures. In the regulation case, all the followers converge into the convex hull spanned by the leaders,while in the dynamic tracking case, not only the positions of the followers converge into the convex hull but also the velocities of the followers converge into the velocity convex hull of the ***, all the theoretical results are illustrated by numerical simulations.

关键词： Containment control directed network topology multi-agent systems nonlinear second-order systems

Real-time fault detection method based on belief rule base for aircraft navigation system

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Chinese Journal of Aeronautics 2013年第3期26卷 717-729页

作者： Zhao Xin wang shicheng Zhang Jinsheng Fan Zhiliang Min Haibo High-Tech Institute of Xi'an

Real-time and accurate fault detection is essential to enhance the aircraft navigation system’s reliability and safety. The existent detection methods based on analytical model draws back at simultaneously detecting gradual and sudden faults. On account of this reason, we propose an online detection solution based on non-analytical model. In this article, the navigation system fault detection model is established based on belief rule base （BRB）, where the system measuring residual and its changing rate are used as the inputs of BRB model and the fault detection function as the output. To overcome the drawbacks of current parameter optimization algorithms for BRB and achieve online update, a parameter recursive estimation algorithm is presented for online BRB detection model based on expectation maximization （EM） algorithm. Furthermore, the proposed method is verified by navigation experiment. Experimental results show that the proposed method is able to effectively realize online parameter evaluation in navigation system fault detection model. The output of the detection model can track the fault state very well, and the faults can be diagnosed in real time and accurately. In addition, the detection ability, especially in the probability of false detection, is superior to offline optimization method, and thus the system reliability has great improvement.

关键词： Belief rule base Fault detection Fault tolerant control Integrated navigation Parameter recursive estimation algorithm

Shear behaviour of a rock bridge sandwiched between incipient joints under the influence of hydraulic pressures

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International Journal of Mining Science and Technology 2023年第2期33卷 233-242页

作者： shicheng wang Xuxu Yang Lichao Li Panpan Sun Lei Yang Fuwei Li Shandong Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Shandong University of Science and TechnologyQingdao 266590China School of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China

The rock bridges sandwiched in incipiently jointed rock mass were considered as barriers that block the fluid seepage,and provide certain shear strength *** better revealing the influence of hydraulic pressure on the failure behaviour of rock bridges,direct shear tests were carried out through a newly proposed method on rock samples that contain two parallel incipient *** developing the gypsum-silicone pad coupling samples,a conventional triaxial test system was qualified to implement direct shear tests with satisfied sealing *** results showed that the rock bridges could be failed through the tensile failure,shear failure and mixed failure *** hydraulic pressure would facilitate the tensile failure mechanism and induce rougher fracture surfaces;while the normal stress would facilitate the shear failure mechanism and induce less rough *** hydraulic pressure reduced the global shear strength of the rock block through reducing the efficient normal stress applied on the rock bridge area,which was highly dependent on the joint persistence,***,because of the iterating occurrence of the hydraulic pressure lag with the fracture propagation,the rock bridge failure stage in the shear stress-shear displacement curves displayed a fluctuation trend.

关键词： Direct shear tests Hydraulic pressure Rock bridge Failure mechanism Hydraulic pressure lag Rock joints

Apatite fission track dating evidence for tectonic movement of Yarlung Zangbo Thrust Zone

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Chinese Science Bulletin 2002年第9期47卷 765-768页

作者： YUAN Wanming HOU Zengqian wang shicheng LI Shengrong Institute of High Energy Physics.Chinese Academy of Sciences Beijing 100080China Institute of Mineral Resources Chinese Academy of Geological SciencesBeijing 100037China China University of Geosciences Beijing 100083China

Fission track geological chronology is an effective method of study on tectonic movement of fault zone. Apatite fission track (AFT) dating analyses of 9-apatite and 4-zircon samples collected from Lhasa to Langkazi, -70-km-long in SN provide an understanding of the age and the uplifting of both sides of the Yarlung Zangbo Thrust Zone (YZTZ) in this work. The AFT ages range from-37 to 14 Ma, indicating the time of major tectono-thermal events, i.e. the continent-continent collision along the YZTZ. Based on the relationship between the AFT ages and the sample elevations, there were two tectonic active periods: -37-20 Ma and 20-14 Ma. In the first period the tectonic event did not bring on differential uplifting. Rapid differential uplifting with rapid cooling, resulting from thrusting, took place in the second period. The vertical displacement was -1020 m and total -2.9 km of overburden has been removed from the present-day surface since cooling below -110°C began. The maximum cooling and denudation

关键词： fission track dating thrusting thermal event uplifting Yarlung Zangbo Zone Tibet.