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Evaluation and Analysis of uplink signal interference in GEO satellite system

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Evaluation and Analysis of uplink signal interference in GEO...

EACS: An Efficient Access Control Scheme for Electronic Publishing in Cloud Computing

第十四届中国卫星导航年会

作者： Xuyu Wang Dongfang Jiang Bingjie Liu Li Wang Haoyuan Yu Hai Sha Heng Wei Yingying Zhao 32021 troops of the PLA

Aiming at the problem of uplink signal interference in the satelliteearth link of GEO satellite system,this paper analyzes the satellite communication link interference model and interference evaluation methods,and the link interference model is constructed by considering various factors ***,the interference evaluation method based on the spectral separation coefficient is used to quantitatively evaluate the attenuation of carrier-to-noise ratio of the useful signals received by the receiving station from multiple *** results show that the interference effect increases with the increase of uplink interference signal power,and presents an exponential increase after reaching a certain value;Under the same interference signal power,the increase of the number of interference stations will lead to the decrease of the attenuation rate of carrier-to-noise ratio of useful signals and gradually *** closer the interference station is deployed to the area near the transmitting station,the more obvious the interference effect will ***,due to the power characteristics of the satellite transparent transponder,its position change in the nearby region has little influence on the interference effect.

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Chinese Journal of Electronics 2018年第1期27卷 60-69页

作者： WU Deming ZHANG Yu WANG Lina HOU Jian XIAO Lei CHEN Wei ZHOU Qing School of Computer Wuhan University Science and Technology on Information Assurance Laboratory Army Aviation Research Institute Air Force Engineering University 95942 troops 24 squad

To guarantee that electronic publications are accessible only to the authorized users via cloud, we propose an Efficient access control scheme(EACS) based on Attribute-based encryption(ABE), which is suitable for fine-grained access control. Compared with existing stateof-the-art schemes, EACS is more practical by following functions. Considering the factor that the user membership may change frequently, EACS has the capability of coping with dynamic membership efficiently. Arbitrary-State is also supported to facilitate the system management and improve efficiency. Besides, we prove in the standard model that the security of EACS is based on the Decisional Bilinear Diffie-Hellman assumption. To evaluate the practicality of EACS, we provide a detailed theoretical performance analysis and a simulation comparison with existing schemes. Both the theoretical analysis and the experimental results show that our proposal is efficient and practical for electronic publishing under cloud environment.

关键词： Electronic publishing Attribute-based encryption Cloud computing Access control Dynamic membership Arbitrary-state

An Optimal Satellite Selection Model of Global Navigation Satellite System Based on Genetic Algorithm

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An Optimal Satellite Selection Model of Global Navigation Sa...

Direct computation of multiconductor transmission line capacitance and charge distribution

第九届中国卫星导航学术年会

作者： Shuyue Zhu 61920 troops

With the increasing number of global navigation satellites and redundant information, the problem of the positioning accuracy and timeliness cannot be taken into account simultaneously has been raised. An optimal satellite selection model of global navigation satellite system based on genetic algorithm(GA) has been suggested. This algorithm is combined with the characteristic of geometric factor calculation model and *** to the users’ requirement of positioning accuracy, the number of selected satellites is adjusted adaptively to ensure timeliness. The mutation crossover method is used to overcome the premature convergence of the satellite selection result caused by the intrinsic defect of GA. Experimental results show that the model can quickly select the satellite under the condition of the required positioning accuracy and improve the comfort of users.

关键词： genetic algorithm geometric dilution precision mutation crossover global navigation satellite system optimal satellite selection

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The Journal of China Universities of Posts and Telecommunications 2009年第5期16卷 119-124页

作者： XU Jun LU Ying-hua ZHANG Li-kun School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876 China The Translation Department of the Second Artillery troops of PLA Beijing 100820 China

The per-unit-length capacitance parameter of multiconductor transmission line （MTL） is commonly extracted with indirect matrix transform method, which is complex and time-consuming. To solve the problem, an improved method to directly compute the MTL capacitance is proposed, which can be applied in the transmission line structure with arbitrary shaped cross-section and arbitrary separate distance. This method imports voltage conversions and matrix operations to simplify the complexity, improves computational efficiency by about 600% with results as accurate as previous method. The novel method presents a clear charge distribution map of MTL, whereas precious method will experience a tortuous process to get charge distribution.

关键词： multiconductor transmission line capacitance matrix charge distribution

Aerodynamic optimization of a high-lift system with adaptive dropped hinge flap

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Chinese Journal of Aeronautics 2022年第11期35卷 191-208页

作者： Qiang JI Yufei ZHANG Haixin CHEN Junke YE School of Aerospace Engineering Tsinghua UniversityBejing 100084China 63870 PLA troops Huayin 714200China Shanghai Aircraft Design and Research Institute Shanghai 200236China

The Adaptive Dropped Hinge Flap(ADHF) is a novel trailing edge high-lift device characterized by the integration of downward deflection spoiler and simple hinge flap, with excellent aerodynamic and mechanism performance. In this paper, aerodynamic optimization design of an ADHF high-lift system is conducted considering the mechanism performance. Shape and settings of both takeoff and landing configurations are optimized and analyzed, with considering the kinematic constraints of ADHF mechanism, and the desired optimization results were obtained after optimization. Sensitivity analysis proves the robustness of the optimal design. Comparison shows that the ADHF design has better comprehensive performance of both mechanism and aerodynamics than the conventional Fowler flap and simple hinge flap design.

关键词： Adaptive dropped hinge flap Aerodynamic design High-Lift aerodynamics Multidisciplinary optimization Optimization of aircraft design

The comparison of statistical features and synoptic circulations between the eastward-propagating and quasi-stationary MCSs during the warm season around the second-step terrain along the middle reaches of the Yangtze River

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Science China Earth Sciences 2020年第8期63卷 1209-1222页

作者： Ruyi YANG Yuanchun ZHANG Jianhua SUN Jun LI Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China University of the Chinese Academy of Sciences Beijing 100049China 31010 PLA troops Beijing 100081China

Mesoscale convective systems(MCSs) around the second-step terrain(106°–113°E, 28°–35°N), along the middle reaches of the Yangtze River, were detected, tracked and classified using a black body temperature(TBB) dataset during May to August 2000–2016(except 2005). The MCSs were divided into eastward-propagating(EP) and quasi-stationary(QS) types, to compare their spatial and temporal distributions and convective intensities, and to identify the favorable synoptic conditions for the formation and evolution of EP MCSs. The results showed that both MCS types occurred most often in July. The EP MCSs were mainly initiated over the eastern regions of the study area, while the QS type mainly originated in the western regions of the study area. Both MCS types mainly formed in the afternoon, but a second peak occurred in the early morning for QS MCSs. The EP MCSs had a larger cloud area at their mature stage and a lower cloud brightness temperature, indicating more intense convection. Additionally, the longer lifetime and further eastward propagation of the EP MCSs meant that they had a great influence on the precipitation over the middle and lower reaches of the Yangtze River. Synoptic circulation analysis demonstrated that the combination of the mid-level low trough east of the Tibetan Plateau(TP), and the western pacific subtropical high(WPSH), favored the formation and eastward propagation of EP MCSs. The positive vertical relative vorticity and stronger vertical wind shear provided dynamic conditions favorable for convective organization and development. Furthermore, a stronger low level jet imported warm and moist air to the eastern edge of, and the regions east of, the second-step terrain. The substantial convergence of water vapor promoted the development and long-lived maintenance of the EP MCSs.

关键词： Second-step terrain Middle reaches of the Yangtze River Mesoscale convection systems.Spatial and temporal distribution Synoptic circulation

Tribological characteristics and self-repairing effect of hydroxy-magnesium silicate on various surface roughness friction pairs

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Journal of Central South University 2011年第5期18卷 1326-1333页

作者：张博徐滨士许一张保森 National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering The Chinese People's Liberation Army 91278 troops School of Materials Science and Engineering Shanghai Jiaotong University

Tribological characteristics and self-repairing effect of hydroxy-magnesium silicate (HMS) dispersed in lubricant oil on steel-to-steel friction pairs with various surface roughness were *** friction-reduction,anti-wear and self-repairing performance of various surface roughness friction pairs were examined by friction testing *** operation comparison was made between SJ10W-40 lubricant with and without *** surface morphology and elementary composition of the grinding cracks were analyzed by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS).The results show that the lubrication state changes from boundary lubrication into mixed lubrication after operation in lubricant with *** friction-reduction,anti-wear and self-repairing performance of the friction pairs with various surface roughness are distinctly *** is a repairing film whose material is different from substrate material on the grinding *** addition,Si,Mg,O,Al and other elements are deposited on the repairing film which contains nanocrystals of these *** HMS self-repairing material possesses superior performance of friction-reduction,anti-wear and self-repairing effects.

关键词： hydroxy-magnesium silicate surface roughness friction wear self-repairing

Military material procurement risk control countermeasures and thinking

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中国国际财经（中英文版） 2015年第10期 6-8页

作者： Dong Ning Li wei 71939 troops

Research on the acquisition and tracking simulation system of light beacon in satellite-ground optical communications

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Optoelectronics Letters 2010年第6期6卷 458-461页

作者：左韬艾勇黄海波苏贵波 School of Electronic Information Wuhan University College of Information Science and Engineering Wuhan University of Science and Technology 61491 troops PLA

The study on the acquisition and tracking simulation system in satellite-ground optical communications is presented *** applying global positioning system(GPS) coordinate calculation,the time needed in initial acquisition of light beacon can be reduced *** predictor is applied to compensate the mechanical hysteresis of tracking system and to improve the dynamic performance of the *** experiments over a 16 km distance on the ground are conducted to verify the tracking of light beacon in satellite-ground optical *** standard deviation of horizontal coordinates is 35.3568 μrad and the maximum offset is 209.3675 μrad in stable tracking.

关键词：卫星光通信地面系统跟踪模拟灯塔 Smith预估补偿采集全球定位系统坐标计算