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An Algorithm for determination of Projectile Attitude Angles in Projectile Trajectory Prediction

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第2期35卷 361-370页

作者： zha Qicheng Rui Xiaoting Yu Hailong Zhou Qinbo Institute of Launch dynamics School of Energy and Power EngineeringNanjing University of Science and Technology

A fast and accurate algorithm is established in this paper to increase the precision of ballistic trajectory *** algorithm is based on the six-degree-of-freedom(6 dOF)trajectory equations,to estimate the projectile attitude angles in every measuring ***,the algorithm utilizes the davidon-Fletcher-Powell(dFP)method to solve nonlinear equations and doppler radar trajectory test information containing only position coordinates of the projectile to reconstruct the angular ***″position coordinates by the test″and″angular displacements by reconstruction″at the end phase of the radar measurement are used as an initial value for the trajectory computation to extrapolate the trajectory impact *** numerical simulations validate the proposed method and demonstrate that the estimated impact point agrees very well with the real ***,other artillery trajectory can be predicted by the algorithm,and other trajectory models,such as 4 dOF and 5 dOF models,can also be incorporated into the proposed algorithm.

关键词： ballistic trajectory impact point prediction davidon-Fletcher-Powell method six-degree-of-freedom trajectory model doppler radar data

A Novel Provable data Possession Scheme Based on geographic Location Attribute

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China Communications 2016年第9期13卷 139-150页

作者： Yaxing zha Shoushan Luo Jianchao Bian Wei Li National Engineering Laboratory of disaster Backup and Recovery Beijing University of Posts and TelecommunicationsBeijing 100876China Information Security Center Beijing University of Posts and TelecommunicationsBeijing 100876China

Increment of mobile cloud video motivates mobile users to utilize cloud storage service to address their demands, cloud storage provider always furnish a location-independent platform for managing user＇s data. However, mobile users wonder if their cloud video data leakage or dynamic migration to illegal service providers. In this paper, we design a novel provable data possession protocol based on data geographic location attribute, which allows data owner to auditing the integrity of their video data, which put forward an ideal choice for remote data possession checking in the mobile cloud storage. In our proposed scheme, we check out whether the video data dynamic migrate to an unspecified location （such as： overseas） by adding data geographic location attribute tag into provable data possession protocol. Moreover, we make sure the security of our proposed scheme under the Computational diffic-Hellman assumption. The analysis and experiment results demonstrate that our proposed scheme is provably secure and efficient.

关键词： cloud storage security provable data possession geographic location security boundary CdH assumption

Current trajectory image-based protection algorithm for transmission lines connected to MMC-HVdC stations using CA-CNN

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Protection and Control of Modern Power Systems 2023年第1期8卷 97-111页

作者： Yingyu Liang Yi Ren Jinhua Yu Wenting zha School of Mechanical Electronic and Information Engineering China University of Mining and Technology(Beijing) Beijing 100083China

In the presence of an MMC-HVdC system,current differential protection(CdP)has the risk of failure in operation under an internal *** addition,CdP may also incur security issues in the presence of current transformer(CT)saturation and *** this paper,a current trajectory image-based protection algorithm is proposed for AC lines connected to MMC-HVdC stations using a convolution neural network improved by a channel attention mechanism(CA-CNN).Taking the dual differential currents as two-dimensional coordinates of the moving point,the moving-point trajectories formed by differential currents have significant differences under internal and external ***,internal faults can be identified using image recognition based on *** is improved by a channel attention mechanism,data augmentation,and adaptive learning *** comparison with other machine learning algorithms,the feature extraction ability and accuracy of CA-CNN are greatly *** fault conditions like different net-work structures,operation modes,fault resistances,outliers,and current transformer saturation,are fully considered to verify the superiority of the proposed protection *** results confirm that the proposed current trajectory image-based protection algorithm has strong learning and generalizability,and can identify internal faults reliably.

关键词： Channel attention mechanism Convolutional neural network(CNN) differential current Current trajectory image Modular multilevel converter-based high voltage direct current(MMC-HVdC)

A New Network Coding Mechanism Balancing Coding Opportunities, Energy and QoS in WSNs

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China Communications 2014年第6期11卷 108-118页

作者： ZHENg Kangfeng WANg Xiujuan zha Xuan XIAO Huan School of Computer Science Beijing University of Posts and Telecommunications School of Computer Science Beijing University of Technology

A new Network Coding mechanism in WSNs(Wireless Sensor Networks), which is named COEQ and aims at balancing coding opportunities, energy and QoS, is proposed and analyzed. Implemented on the basis of traditional AOdV protocol, COEQ evaluates several metrics of paths comprehensively with TOPSIS method including minimum remaining energy, coding opportunities, QoS and so on, so as to select the optimal transmitting route. Experiments on NS[2] show that COEQ can improve throughput and save energy when the transmitting rate is low.

关键词： network coding wireless sensor network QoS TOPSIS

A curvelet-based method to determine wave directions from nautical X-band radar images

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Acta Oceanologica Sinica 2018年第1期37卷 11-19页

作者： zha.guozhen HE Qingyou gUAN Changlong CHEN Jitao College of Oceanic and Atmospheric Sciences Ocean University of China Qingdao 266100 China Physical Oceanography Laboratory Ocean University of China Qingdao 266100 China State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Science Guangzhou 510301 China Hydrology Bureau of Yellow River Conservancy Commission Zhengzhou 450004 China

A new method to determine wave directions from nautical X-band images is proposed. The signatures of ocean waves show obvious scale and directional characteristics in nautical X-band radar images. Curvelet transform（CT） possesses very high scale and directional sensitivities. Therefore, it has good capability to analyze ocean wave fields. The radar images are decomposed at different scales, in different directions, and at different positions by CT, and curvelet coefficients are obtained. given to the scale and directional characteristics of surface waves,the information of ocean waves is centralized in the curvelet coefficients of certain directions and at certain ***, the wave orientations can be determined. The 180 ambiguity is removed by calculating crosscorrelation coefficients（CCCs） between continuous collected images. The proposed method is verified by the dataset collected on the Northwest coast of the zha.gzi Island in the Yellow Sea of China from March to April 2009.

关键词： X-band radar wave direction surface wave curvelet transform

PPP-RTK functional models formulated with undiferenced and uncombined gNSS observations

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Satellite Navigation 2022年第1期3卷 139-153,I0005页

作者： Baocheng zha.g Pengyu Hou Jiuping zha Teng Liu State Key Laboratory of geodesy and Earth’s dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhanChina College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijingChina State Key Laboratory of Satellite Navigation System and Equipment Technology The 54th Research Institute of China Electronics Technology Group CorporationShijiazhuangChina

Technique PPP-RTK combines the advantages of both the Precise Point Positioning(PPP)and the Real-Time Kinematic(RTK)*** the emergence of multi-frequency global Navigation Satellite System(gNSS)observations,it is preferable to formulate PPP-RTK functional models based on original(undiferenced and uncombined)*** there exist many variants of the undiferenced and uncombined PPP–RTK models,a unifed theoretical framework needs developing to link these *** this contribution,we formulate a class of undiferenced and uncombined PPP-RTK functional models in a systematic way and cast them in a unifed *** framework classifes the models into a code-plus-phase category and a phase-only *** category covers a variety of measurement scenarios on the network side,ranging from small-,medium-to large-scale *** each scenario,special care has been taken of the distinct ionospheric constraints and the diference between Code division Multiple Access(CdMA)and Frequency division Multiple Access(FdMA)*** key to systematically formulating these models lies in how to deal with the rank defciency problems *** opt for the Singularity-basis(S-basis)theory,giving rise to the full-rank observation equations in which the estimable parameters turn out to be the functions of original parameters and those selected as the *** the sequel,it becomes straightforward to derive for each scenario the user model as it,more or less,amounts to the single-receiver network *** from the presented theoretical framework,the relationships and diferences between various undiferenced and uncombined PPP-RTK models become clear,which can lead to the better use of these models in a specifc situation.

关键词： global navigation satellite system(gNSS) Ambiguity resolution-enabled precise point positioning(PPP-RTK) Singularity-basis(S-basis) Undiferenced and uncombined Frequency division multiple access(FdMA) Phaseonly

Further results on differentially 4-uniform permutations over F2^2m

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Science China Mathematics 2015年第7期58卷 1577-1588页

作者： zha ZhengBang HU Lei SUN SiWei SHAN JinYong School of Mathematical Sciences Luoyang Normal University State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of Sciences Beijing Center for Mathematics and Information Interdisciplinary Sciences

We present several new constructions of differentially 4-uniform permutations over F22 mby modifying the values of the inverse function on some subsets of F22 m. The resulted differentially 4-uniform permutations have high nonlinearities and algebraic degrees, which provide more choices for the design of crytographic substitution boxes.

关键词： permutation differentially 4-uniform function nonlinearity algebraic degree

design and research of signal-level airborne electronic reconnaissance simulation system

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International Journal of Modeling, Simulation, and Scientific Computing 2018年第4期9卷 139-154页

作者： Yang zha Chaoxuan Shang Zhuangzhi Han department of Electronic and Optical Engineering Army Engineering University 050003 Shijiazhuang HebeiP.R.China

Airborne passive electronic reconnaissance equipment has developed rapidly during recent ***,because of its expensive and unavailable military features,the simulation realization of these equipment needs to be *** the smaller the simulation particle is,the better the simulation system will *** this study,a signal-level airborne electronic reconnaissance simulation system was *** model and simulation realization of each part are introduced in this *** on the shortness of traditional signal sorting methods,we creatively proposed a presorting method based on the Euclidean distance inside signal *** results show that the presorting method based on Euclidean distance successfully reduced the pressure on main sorting and appeared good for signal *** test results of each model built in this study are also shown in the *** study provides a new thought on the realization of airborne electronic reconnaissance equipment and benefits the development of electronic countermeasure.

关键词： Electronic reconnaissance signal level simulation system Euclidean distance signal sorting.

NUMERICAL ANALYSIS OF THE UNSTEAdY FORCE IN INSECT FORWARd FLIgHT

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Journal of Hydrodynamics 2006年第2期18卷 143-147页

作者： zha Xiong-quan LU Xi-yun YIN Xie-zhen department of Mechanics and Mechanical Engineering University of Science and Technology of China Hefei 230026 China

The objective of this study is to get into physical insights to the unsteady force and the relevant mechanisms in forward flight of insects. Unsteady force in the forward flight was studied, based on a virtual model problem of a foil with oscillating translation and rotation in a uniform flow, by solving the two-dimensional incompressible Navier-Stokes equations with a finite element method. The effects of typical parameters, including the advance ratio, the inclined angle of stroke plane, the stroke amplitude, and the amplitude of pitching angle of attack, on the forces and the flow structures were analyzed.

关键词： unsteady flow vortex dynamics thrust and lift,flapping motion biomechanics