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Design optimization of a hexapod vibration isolation system for electro-optical payload

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Chinese Journal of Aeronautics 2024年第2期37卷 330-342页

作者： jing LI weipeng LI Xiaoyan ZHANG Hai HUANG School of Astronautics Beihang UniversityBeijing 100191China

The electro-optical payloads on mobile platforms generally suffer undesirable vibrations generated by maneuvers and *** vibrations are in six degrees of freedom and cause line-of-sight jitters,resulting in image blurring and loss of tracking *** this paper,a Hexapod Vibration Isolation System(HVIS)is proposed and optimized to solve this *** optimization aims to centralize and minimize the natural frequencies of HVIS,for expanding the vibration isolation bandwidth and improving the vibration isolation in the higher frequency *** that the design space for HVIS is limited and interfered with the frames of the mobile platform,a non-collision algorithm is proposed and applied in the optimization to obtain the feasible optimal *** optimization result shows that the natural frequency bandwidth has been reduced by 42.9%,and the maximum natural frequency is reduced by 30.2%.The prototypes of initial and optimal designs are manufactured and *** simulated and experimental results demonstrate the validity of the optimization,and the optimal design provides a maximum of 15 dB more isolation in rotation direction than the initial design.

关键词： Electro-optical payload Vibrations Isolation system Hexapod Optimization Non-collision design

Hybrid prefix OFDM with spatial modulation toward terahertz broadband transmission

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Science China(Information Sciences) 2020年第8期63卷 53-55页

作者： Tiebin WANG weipeng jing Wenlong SONG Information and Computer Engineering College Northeast Forestry University

Dear editor,In the development of 6G, terahertz communications [1] have attracted much attention owing to their potential for providing wireless broadband connections with even higher frequency resources. Furthermore, new transmission technologies have been widely considered for supporting future 6G systems [2]. Specifically, the spatial

关键词： spatial modulation ofdm cyclic prefix terahertz multiple path fading

Corrosion Behavior of Graphene Nanosheets Reinforced Magnesium Matrix Composites in Simulated Body Fluids

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 525-536页

作者： Liwen Chen Jianhui jing Lulu Zhang jing Li weipeng Chen Limin Li Yuan Zhao Hua Hou Yuhong Zhao School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-Performance Al/Mg Alloy MaterialsNorth University of ChinaTaiyuan 030051China Shanxi Key Laboratory of Advanced Manufacturing Technology School of Mechanical EngineeringNorth University of ChinaTaiyuan 030051China School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Magnesium(Mg)alloy is considered as a promising biodegradable implant material but restricted to rapid ***,the new strategies based on thixomolding process had been explored to utilize the outstanding anti-permeability of graphene nanosheets(GNPs)while inhibit its galvanic corrosion with the matrix,so as to improve the corrosion resistance of *** agglomerate of GNPs with 0.9 wt%content is the main reason for the deterioration of corrosion performance due to the formation of micro-galvanic *** grain refinement of composites with 0.6 wt%content had positive effects on the better corrosion *** process adjusting,the unique distributions of GNPs along grain boundaries play a vital role in improving the corrosion *** can be ascribed to the following mechanisms:(I)The barriers can be established between the Mg matrix and corrosive medium,hence blocking the charge transfer at the interface;(II)The GNPs can effectively promote apatite deposition on the Mg matrix,leading to form dense apatite layers and prevent the further invasion of SBF;(III)The GNPs acting as reinforcements exists in the corrosion layer and apatite layer,impede the apatite layer falling off from the Mg *** findings broaden the horizon for biomedical applications in Mg matrix composites to realize desired performances.

关键词： Magnesium matrix composite Graphene nanosheets Corrosion resistance

Multi-DAGs Scheduling Integrating with Security and Availability in Cloud Environment

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Chinese Journal of Electronics 2015年第4期24卷 709-716页

作者： LIU Yaqiu SHAO Hongrun jing weipeng QIU Zhaowen The College of Information and Computer Engineering Northeast Forestry University Heilongjiang Province Engineering Technology Research Centre for Forestry Ecological Big Data Storage and High Performance (Cloud) Computing

In view of the issue concerns multiple Directed acyclic graphs(DAGs) scheduling in multi-tenant cloud computing environment, a scheduling strategy that integrate security and availability is proposed to satisfy the tenants’ requirements for resource security and availability, as thus it can not only protect the users’ privacy and data security but also advance the success rate. The proposal assesses resource reputation to ensure jobs can be scheduled onto relatively security nodes; during task scheduling, it classifies the DAGs to achieve fairness; in the process of resources allocation, the objective function would maximize the user’s security satisfaction and minimize the deviation of availability; meanwhile, it takes advantage of "time chips" flexibly to promote resource utilization rate; afterwards, we present a Greedy algorithm integrating with security and availability(GISA) to implement the strategy. The experimental results show the correctness and superior of the novel strategy.

关键词： Multi-DAGs scheduling Security Availability Resource utilization

基于BOVW和SVM的城市土地类型遥感变化监测研究

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南京林业大学学报（自然科学版） 2023年第3期47卷 37-44页

作者：黄靖舒高心丹景维鹏东北林业大学信息与计算机工程学院林学院黑龙江哈尔滨150040

【目的】研究城市土地类型的变化,分析城市进化过程对环境气候、城市发展以及政府决策产生的影响。【方法】以15~30 m分辨率的NWPU-RESISC45标准数据集和哈尔滨城区Landsat 8遥感影像为实验数据,制作了包含城市建筑及道路、水体、植被... 详细信息

【目的】研究城市土地类型的变化,分析城市进化过程对环境气候、城市发展以及政府决策产生的影响。【方法】以15~30 m分辨率的NWPU-RESISC45标准数据集和哈尔滨城区Landsat 8遥感影像为实验数据,制作了包含城市建筑及道路、水体、植被、裸地4种土地类型的遥感影像数据集。在实验数据中加入纹理信息,提取SIFT(scale-invariant feature transform, SIFT)特征点。通过K-means聚类算法获取包含大量语义信息的视觉词典,从而构造视觉词袋模型(bag of visual words, BOVW)。然后将BOVW提取的特征点与支持向量机(support vector machine, SVM)分类器结合,对制作的数据集进行分类。最后,利用2013年、2019年同一季节Landsat 8影像,以哈尔滨市松北区为例计算各土地类型的位置及面积变化信息。【结果】基于BOVW和SVM的分类结果与5种单一分类模型和3种“特征提取+分类器”模型对比,发现使用尺寸为550个词汇的视觉词典时,本研究模型的分类与变化监测精确度分别为79.40%、79.29%。结合哈尔滨城市具体数据的监测结果表明,在2013—2019年间,哈尔滨市松北区城市建筑及道路与植被类型的覆盖面积减少明显,水体与裸地类型的覆盖面积增加,这一变化情况符合近年来哈尔滨市政府陆续推出的环境保护五年规划,以及其总体规划中合理控制城市规模的相关政策要求。【结论】对于时间跨度长、分辨率不高的Landsat遥感影像,BOVW和SVM的变化监测模型在土地类型变化监测方面效果良好,在一定程度上可提高分类与变化监测的精度,为土地类型变化监测提供借鉴。

关键词：土地类型监测视觉词袋模型(BOVW) 支持向量机(SVM) 城市变化监测分类后比较法哈尔滨市

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基于深度多相似性哈希方法的遥感图像检索

计算机工程 2023年第2期49卷 206-212页

作者：何悦陈广胜景维鹏徐泽堃东北林业大学信息与计算机工程学院哈尔滨150040

哈希方法由于低存储、高效率的特性而被广泛应用于遥感图像检索领域。面向遥感图像检索任务的无监督哈希方法存在伪标签不可靠、图像对的训练权重相同以及图像检索精度较低等问题,为此,提出一种基于深度多相似性哈希(DMSH)的遥感图像检... 详细信息

哈希方法由于低存储、高效率的特性而被广泛应用于遥感图像检索领域。面向遥感图像检索任务的无监督哈希方法存在伪标签不可靠、图像对的训练权重相同以及图像检索精度较低等问题,为此,提出一种基于深度多相似性哈希(DMSH)的遥感图像检索方法。针对优化伪标签和训练关注度分别构建自适应伪标签模块(APLM)和成对结构信息模块(PSIM)。APLM采用K最近邻和核相似度来评估图像间的相似关系,实现伪标签的初始生成和在线校正。PSIM将图像对的多尺度结构相似度映射为训练关注度,为其分配不同的训练权重从而优化深度哈希学习。DMSH通过Swin Transformer骨干网络提取图像的高维特征,将基于语义相似矩阵的伪标签作为监督信息以训练深度网络,同时网络在两个基于不同相似度设计的模块上实现交替优化,充分挖掘图像间的多种相似信息进而生成具有高辨识力的哈希编码,实现遥感图像的高精度检索。实验结果表明,DMSH在EuroSAT和PatternNet数据集上的平均精度均值较对比方法分别提高0.8%~3.0%和9.8%~12.5%,其可以在遥感图像检索任务中取得更高的准确率。

关键词：深度无监督学习遥感图像检索特征提取哈希学习伪标签

A NOVEL PFMAC PROTOCOL FOR WIRELESS SENSOR NETWORK BASED ON PREDICTION AND FEEDBACK METHOD

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Journal of Electronics(China) 2011年第4期28卷 488-495页

作者： LiuYaqiu Bian Li jing weipeng Zhang Qianlong Information and Computer Engineering College Northeast Forestry University Harbin 150001 China

In view of the problem that existing Media Access Control(MAC) protocols can not pro-vide real-time monitor on network conditions,this paper puts forward a new MAC protocol- Predict and Feedback MAC(PFMAC) which can predict the channel's congestion level *** dominant idea of the new scheme is to record the channel's busy or idle situation in the backoff stage by sending Sensor Nodes(SNs),and according to the congestion level every SN can change the contention window adaptively when send packets successfully to minimize collisions,saving energy and channel *** result of simulation shows that compared with other MAC protocols,the PFMAC protocol can improve network throughput and reduce energy consumption in high speed network en-vironment.

关键词： Media Access Control(MAC) Backoff algorithm Predict and Feedback MAC(PFMAC) Contention window

An uncertainty investigation for liner impedance eduction methods

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Chinese Journal of Aeronautics 2024年第3期37卷 49-59页

作者： Weihao SHI Xiaodong jing School of Energy and Power Engineering Beihang UniversityBeijing 100191China

Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic *** this end,it is important to fully investigate the uncertainty problem,to which only limited attention has been devoted so *** paper considers the possibility of acoustically-induced structural vibration as a nonnegligible uncertainty or error source in impedance eduction *** the frequency moves away from the resonant frequency,with the increase in the value of cavity reactance,the acoustic particle velocity inside liner orifices possibly decreases to the extent comparable to the vibration velocity of liner facing ***,the acoustically-induced vibration,although generally being weak except at the inherent structural frequencies,may considerably affect the impedance eduction results near the anti-resonant frequency where the liner has poor *** demonstrate the effect of structural vibration,the vibration velocity of liner facing sheet is estimated from the experimentally educed admittance of the liner samples whose orifices are sealed with ***,a three-dimensional numerical model is set up,in which normal particle velocity is introduced over the solid portion of liner facing sheet to imitate structural vibration,rather than directly solving the acoustic-structural coupling *** shown by the results,the vibration of liner facing sheet,whose velocity is as small as estimated by the experiment,can result in anomalous deviation of the educed impedance from the impedance model near the anti-resonant *** trend that the anomalous deviation varies with frequency is numerically captured.

关键词： Impedance eduction Uncertainty analysis Acoustically-induced structural vibration Anti-resonant frequency Perforated liner

A review on numerical studies of airflow dynamics and particle deposition in human respiratory system Author links open overlay panel

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Particuology 2024年第8期91卷 351-377页

作者： Hao jing Xinguang Cui School of Aerospace Engineering Huazhong University of Science and TechnologyWuhan430074China

Accurate assessment and prediction of airflow dynamics and particle deposition in the human respiratory tract are essential for human health,involving inhaled drugs for treating various diseases and toxic particles that can cause *** intricate process involves complex multiphase flow with distinct respiratory *** fluid dynamics(CFD)acts as a bridge,overcoming the limitations of in vivo and in vitro experiments and providing a means to fully comprehend and reveal the fundamental mechanisms of respiratory flow and particle behavior on a microscopic *** paper provides a comprehensive overview and concise summary of recent advancements in the numerical simulation of airflow and particle deposition in the human respiratory ***,it summarizes the transition of respiratory tract models from segmented models to emerging physiological characteristic models and whole-lung airway models,and the latest developments on the effects of key factors such as geometric variations,respiratory patterns,and particle physical/chemical properties on respiratory flow and particle deposition.A notable focus of this review is on emerging physiological characteristics models and their associated complex airflow and particle dynamics inside *** paper concludes with recommendations for future research to further advance the development of this field.

关键词： Airflow dynamics Particle deposition Human respiratory system Numerical modeling