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Space/Air Covert Communications:Potentials,Scenarios,and Key Technologies

China Communications 2024年第3期21卷 1-18页

作者： Mao Haobin Liu Yanming zhu lipeng Mao Tianqi Xiao Zhenyu Zhang Rui Han zhu Xia Xianggen School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore School of Science and Engineering Shenzhen Research Institute of Big Datathe Chinese University of Hong KongShenzhenGuangdong 518172China Department of Electrical and Computer Engineering University of HoustonHoustonTX 77004USA Department of Computer Science and Engineering Kyung Hee UniversitySeoulSouth Korea446-701 Department of Electrical and Computer Engineering University of DelawareNewarkDE 19716USA

Space/air communications have been envisioned as an essential part of the next-generation mobile communication networks for providing highquality global connectivity. However, the inherent broadcasting nature of wireless propagation environment and the broad coverage pose severe threats to the protection of private data. Emerging covert communications provides a promising solution to achieve robust communication security. Aiming at facilitating the practical implementation of covert communications in space/air networks, we present a tutorial overview of its potentials, scenarios, and key technologies. Specifically, first, the commonly used covertness constraint model, covert performance metrics, and potential application scenarios are briefly introduced. Then, several efficient methods that introduce uncertainty into the covert system are thoroughly summarized, followed by several critical enabling technologies, including joint resource allocation and deployment/trajectory design, multi-antenna and beamforming techniques, reconfigurable intelligent surface(RIS), and artificial intelligence algorithms. Finally, we highlight some open issues for future investigation.

关键词： artificial intelligence(AI) sixth generation(6G) space-air-ground integrated networks(SAGINs) space/air covert communications

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Multi-Resource Collaborative Service Restoration of a Distribution Network with Decentralized Hierarchical Droop Control

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Protection and Control of Modern Power Systems 2024年第1期9卷 19-37页

作者： Wei Zhang Cong Zhang Jiayong Li lipeng zhu Shiran Cao Wen Huang Zhikang Shuai College of Electrical and Information Engineering Hunan UniversityChangshaChina Hunan University ChangshaChina CSEE Journal of Power and Energy Systems Chinese Journal of Electrical Engineerin

To improve the resilience of distribution networks(DNs)in the event of extreme natural disasters such as typhoons and rainstorms,it is imperative to efficiently implement distribution service restoration(DSR)to restore loads as soon as *** previous studies,DSR has mainly adopted the distributed resource model with droop or PQ *** inhibits the exploitation of the potential of distributed generators(DGs)in load restoration when the DN loses support from the upstream transmission ***,this paper proposes a multi-resource collaborative service restoration(MRCSR)approach for DNs incorporating local soft open points,DGs,and tie *** MRCSR model is developed by integrating a decentralized hierarchical droop control(DHDC)strategy and incorporating the frequency and voltage features of the load demand.A two-stage iterative feedback optimization(TSIFO)algorithm is then developed to analyze the MRCSR model in an accurate and efficient ***,the proposed model and algo-rithm are tested on the modified IEEE 33-bus system and a practical distribution system of the Taiwan Power Company to verify their effectiveness and advantages over existing approaches.

关键词： service Service integrating

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融合深度误差反馈学习和注意力机制的短期风电功率预测

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电力系统保护与控制 2024年第4期52卷 100-108页

作者：胡宇晗朱利鹏李佳勇李杨曾杨郑李梦千帅智康湖南大学电气与信息工程学院湖南长沙410082

为提高风电功率预测精度,提出了一种有机融合深度反馈学习与注意力机制的短期风电功率预测方法。首先,以风电场数值天气预报(numerical weather prediction,NWP)为原始输入,基于双层长短期记忆网络(long short-term memory,LSTM)模型对... 详细信息

为提高风电功率预测精度,提出了一种有机融合深度反馈学习与注意力机制的短期风电功率预测方法。首先,以风电场数值天气预报(numerical weather prediction,NWP)为原始输入,基于双层长短期记忆网络(long short-term memory,LSTM)模型对风电功率进行初步预测。其次,利用极端梯度提升(eXtreme gradient boosting,XGBoost)算法构建误差估计模型,以便在给定未来一段时间内NWP数据的情况下对初步预测误差进行快速估计。然后,利用自适应白噪声完备集成经验模态分解法(complete ensemble empirical mode decomposition with adaptive noise,CEEMDAN)将初步预测误差分解为不同频段的误差序列,并将其作为附加性反馈输入,对风电功率进行二次预测。进一步在二次预测模型中引入注意力机制,为风电功率预测序列与误差序列动态分配权重,由此引导预测模型在学习过程中充分挖掘学习与误差相关的关键特征。最后,仿真结果表明所提方法可显著提高短期风电功率预测的可靠性。

关键词：风电功率预测深度学习反馈学习长短时记忆单元注意力机制

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UAV Communications with Millimeter-Wave Beamforming:Potentials,Scenarios,and Challenges

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China Communications 2020年第9期17卷 147-166页

作者： Zhenyu Xiao lipeng zhu Xiang-Gen Xia School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Department of Electrical and Computer Engineering University of DelawareNewarkDE 19716USA

Unmanned aerial vehicle(UAV)has been widely used in many fields and is arousing global *** the resolution of the equipped sensors in the UAV becomes higher and the tasks become more complicated,much higher data rate and longer communication range are required in the foreseeable *** the millimeter-wave(mm Wave)band can provide more abundant frequency resources than the microwave band,much higher achievable rate can be guaranteed to support UAV services such as video surveillance,hotspot coverage,and emergency communications,*** flexible mm Wave beamforming can be used to overcome the high path loss caused by the long propagation *** this paper,we study three typical application scenarios for mm Wave-UAV communications,namely communication terminal,access point,and backbone *** present several key enabling techniques for UAV communications,including beam tracking,multi-beam forming,joint Tx/Rx beam alignment,and full-duplex relay *** show the coupling relation between mm Wave beamforming and UAV positioning for mm Wave-UAV ***,we summarize the challenges and research directions of mm Wave-UAV communications in detail.

关键词： unmanned aerial vehicle(UAV) millimeter-wave(mmWave)communications beamforming beam tracking deployment

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面向6G通信感知一体化的固定与可移动天线技术

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信号处理 2024年第8期40卷 1377-1407页

作者：曾勇董珍君王蕙质朱立鹏洪子尧姜庆基王东明金石张瑞东南大学移动通信全国重点实验室江苏南京210096 紫金山实验室江苏南京211111 新加坡国立大学电子与计算机工程系新加坡117583 香港中文大学(深圳) 深圳大数据研究院广东深圳518172

多天线技术通过在收发端部署天线阵列,从而提供额外的空间自由度(degrees of freedom,DoFs),大幅提升了无线通信的可靠性与有效性。与此同时,多天线技术应用于雷达感知领域,实现了空间角度分辨能力并提升了感知自由度,大幅增强了无线感... 详细信息

多天线技术通过在收发端部署天线阵列,从而提供额外的空间自由度(degrees of freedom,DoFs),大幅提升了无线通信的可靠性与有效性。与此同时,多天线技术应用于雷达感知领域,实现了空间角度分辨能力并提升了感知自由度,大幅增强了无线感知性能。然而,无线通信与雷达感知领域在过去数十年里独立发展。因此,尽管多天线技术在这两个领域分别取得了巨大的进步,但并没有通过发挥它们的协同作用来实现深度融合。随着感知与通信的融合被确定为第六代(the sixth-generation,6G)移动通信网络的典型应用场景之一,多天线技术的发展面临新的机遇以填补上述空白。为此,本文围绕未来天线阵列规模持续扩张、阵列架构更加多样、阵列形态更为灵活等发展趋势,对面向6G通信感知一体化的多天线技术进行综述。首先介绍未来多天线的不同架构类型,包括以传统紧凑式阵列和新兴稀疏阵列为代表的集中式阵列架构、以无蜂窝大规模MIMO(multiple-input multiple-output)为代表的分布式天线架构,以及三维连续空间阵元位置与朝向灵活可调的可移动天线/流体天线。然后,本文将介绍基于上述天线架构的远场/近场信道建模,并进行通信与感知性能分析。最后总结不同天线架构的特点,并展望解决因天线阵列规模的持续扩展及阵列形态的灵活多变引起的信道状态信息获取困难的新思路。

关键词：第六代移动通信多天线技术通信感知一体化信道建模集中式阵列分布式阵列可移动天线

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Third-order nonlinear optical properties of WTe2 films synthesized by pulsed laser deposition

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Photonics Research 2019年第12期7卷 1493-1500页

作者： MI HE YEQUAN CHEN lipeng zhu HUAN WANG XUEFENG WANG XINLONG XU ZHANYU REN Shaanxi Joint Laboratory of Graphene State Key Laboratory Incubation Base of Photoelectric Technology and Functional MaterialsInternational Collaborative Center on Photoelectric Technology and Nano Functional MaterialsInstitute of Photonics&Photon-TechnologyNorthwest UniversityXi'an 710069China National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced MicrostructuresSchool of Electronic Science and EngineeringNanjing UniversityNanjing 210093China School of Electronic Engineering Xi'an University of Posts and TelecommunicationsXi'an 710121China

The prominent third-order nonlinear optical properties of WTe2 films are studied through the Z-scan technique using a femtosecond pulsed laser at 1030 ***-aperture(OA)and closed-aperture(CA)Z-scan measurements are performed at different intensities to investigate the nonlinear absorption and refraction properties of WTe2 *** Z-scan results show that WTe2 films always hold a saturable absorption characteristic without transition to reverse saturable ***,a large nonlinear absorption coefficientβis determined to be-3.37×10^3 cm∕GW by fitting the OA Z-scan curve at the peak intensity of 15.603 GW∕cm^*** addition,through the slow saturation absorption model,the ground state absorption cross section,excited state absorption cross section,and absorber's density were found to be 1.4938×10^-16 cm^2,1.2536×10^-16 cm^2,and 6.2396×10^20 cm^-3,*** Z-scan results exhibit a classic peak–valley shape of the CA Z-scan signal,which reveals a self-defocusing optical effect of WTe2 films under the measured ***,a considerable nonlinear refractive index value n2 can be obtained at-1.629×10^-2 cm^2∕***,the values of the real and imaginary parts of the third-order nonlinear susceptibility of WTe2 are roughly estimated to be-5.93×10^-9 and-1.01×10^-8 esu with the help of first-principles ***2 possesses sizeable thirdorder nonlinear coefficients compared with other materials,which suggests that it has great potential to improve performance in nonlinear optical devices.

关键词： optical nonlinear absorption

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Deadline based scheduling for data-intensive applications in clouds

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The Journal of China Universities of Posts and Telecommunications 2016年第6期23卷 8-15页

作者： Fu Xiong Cang Yeliang zhu lipeng Hu Bin Deng Song Wang Dong School of Computer Science and Technology Nanjing University of Posts and Telecommunications Nanjing 210023 China Global Energy Interconnection Research Institute Beijing 102209 China Institute of Advanced Technology Nanjing University of Posts and Telecommunications Nanjing 210023 China State Grid Nantong Power Supply Company Nantong 226001 China

Cloud computing emerges as a new computing pattern that can provide elastic services for any users around the world. It provides good chances to solve large scale scientific problems with fewer efforts. Application deployment remains an important issue in clouds. Appropriate scheduling mechanisms can shorten the total completion time of an application and therefore improve the quality of service（QoS） for cloud users. Unlike current scheduling algorithms which mostly focus on single task allocation, we propose a deadline based scheduling approach for data-intensive applications in clouds. It does not simply consider the total completion time of an application as the sum of all its subtasks＇ completion time. Not only the computation capacity of virtual machine（VM） is considered, but also the communication delay and data access latencies are taken into account. Simulations show that our proposed approach has a decided advantage over the two other algorithms.

关键词： virtual machine placement cloud computing data intensive deadline based

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Comprehensive modeling and parameter identification of wind farms based on wide-area measurement systems

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Journal of Modern Power Systems and Clean Energy 2016年第3期4卷 383-393页

作者： Yinfeng WANG Chao LU lipeng zhu Guoli ZHANG Xiu LI Ying CHEN State Key Laboratory of Power System Department of Electrical EngineeringTsinghua UniversityBeijing 100084China Power Research Institute Eastern Inner Mongolia Power Grid of ChinaSaihan DistrictHohhotChina

With intermittence and stochastics of wind power largely introduced into power systems, power system stability analysis and control is in urgent need of reliable wind farm models. Considering the superiority of wide-area measurement systems, this paper develops a novel methodology for practical synchrophasor measurement-based modeling and parameter identification of wind farms. For the sake of preserving basic structural characteristics and control patterns simultaneously, a comprehensive wind farm model is constructed elaborately. To improve the efficiency of the identification procedure,dominant parameters are classified and selected by trajectory sensitivity analysis. Furthermore, an improved genetic algorithm is proposed to strengthen the capability of global optimization. The test results on the WECC benchmark system and the CEPRI 36-bus system demonstrate the effectiveness and reliability of the proposed modeling and identification methodology.

关键词： Wind farm Trajectory sensitivity Dominant parameter Improved genetic algorithm(IGA) Parameter identification

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Accurate querying of frequent subgraphs in power grid graph data

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Global Energy Interconnection 2019年第1期2卷 78-84页

作者： Aihua Zhou lipeng zhu Xinxin Wu Hongbin Qiu Global Energy Interconnection Research Institute Co.Ltd Power Systems Artificial Intelligence Joint Laboratory of SGCC Nanjing University of Posts and Telecommunications

With the development of information technology, the amount of power grid topology data has gradually increased. Therefore, accurate querying of this data has become particularly important. Several researchers have chosen different indexing methods in the filtering stage to obtain more optimized query results because currently there is no uniform and efficient indexing mechanism that achieves good query results. In the traditional algorithm, the hash table for index storage is prone to "collision" problems, which decrease the index construction efficiency. Aiming at the problem of quick index entry, based on the construction of frequent subgraph indexes, a method of serialized storage optimization based on multiple hash tables is proposed. This method mainly uses the exploration sequence to make the keywords evenly distributed; it avoids conflicts of the stored procedure and performs a quick search of the index. The proposed algorithm mainly adopts the "filterverify" mechanism; in the filtering stage, the index is first established offline, and then the frequent subgraphs are found using the "contains logic" rule to obtain the candidate set. Experimental results show that this method can reduce the time and scale of candidate set generation and improve query efficiency.

关键词： Power grid Graph database Graph computing Multi-Hash table Frequent subgraphs

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基于3D视角的汽轮机叶片抛光量检测

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模具制造 2024年第8期24卷 48-50页

作者：周淑容郑浩聂采高钱桂名朱丽鹏四川职业技术学院智能制造学院四川遂宁629000

叶片是汽轮机中一个非常重要的零件,它的形状和加工表面质量是汽轮机性能好坏的一个重要影响因素。在叶片生产中,抛光工序又是其中一个关键工序。有公司正研究采用机器人来代替人工作业,但在机器人打磨过程中发现,叶片抛光过程中抛光量... 详细信息

叶片是汽轮机中一个非常重要的零件,它的形状和加工表面质量是汽轮机性能好坏的一个重要影响因素。在叶片生产中,抛光工序又是其中一个关键工序。有公司正研究采用机器人来代替人工作业,但在机器人打磨过程中发现,叶片抛光过程中抛光量的测量是一个难题。探讨了采用无接触的3D测量方式对叶片的抛光量进行检测的方法。

关键词：叶片汽轮机抛光 3D测量

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