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Analysis of reflected signal of quad rotor UAV based on model fitting in mobile communication system

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Journal of Systems Engineering and Electronics 2022年第1期33卷 97-104页

作者： li xiaohui FANG Cong FAN Tao School of Telecommunication Engineering Xidian UniversityXi’an 710071China Guangzhou Institute of Technology Xidian UniversityGuangzhou 510555China

In view of the many scenes of unmanned aerial vehicle(UAV)detection,a third-party signal source is used to design a receiver to monitor the *** is of great significance to understand the reflection of the signal illuminating the *** the communication base station(BS)signal as the third-party signal source,and considering the complete transmission link,reflection changes and loss fading of the communication signal,this study conducts model fitting for irregular UAV targets,simplifying complex targets into a combination of simple ***,the influence of the dielectric constant of the target surface and the signal irradiation angle on the signal reflection is *** analysis shows that the simulation results of this model fitting method are consistent with the results of other literature,which provides theoretical support for the detection of low and slow small targets such as UAVs.

关键词： mobile communication signal quad rotor unmanned aerial vehicle(UAV) signal reflection model fitting

UBSS and blind parameters estimation algorithms for synchronous orthogonal FH signals

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Journal of Systems Engineering and Electronics 2014年第6期25卷 911-920页

作者： Weihong Fu Yongqiang Hei xiaohui li State Key Lab of Integrated Service Networks Xidian University

By using the sparsity of frequency hopping（FH） signals,an underdetermined blind source separation（UBSS） algorithm is presented. Firstly, the short time Fourier transform（STFT） is performed on the mixed signals. Then, the mixing matrix, hopping frequencies, hopping instants and the hooping rate can be estimated by the K-means clustering algorithm. With the estimated mixing matrix, the directions of arrival（DOA） of source signals can be obtained. Then, the FH signals are sorted and the FH pattern is obtained. Finally, the shortest path algorithm is adopted to recover the time domain signals. Simulation results show that the correlation coefficient between the estimated FH signal and the source signal is above 0.9 when the signal-to-noise ratio（SNR） is higher than 0 d B and hopping parameters of multiple FH signals in the synchronous orthogonal FH network can be accurately estimated and sorted under the underdetermined conditions.

关键词： frequency hopping(FH) underdetermined blind source separation(UBSS) parameters estimation clustering

Diffusion characteristics of oxygenic–thermal coupled airflow in high-altitude sleeping environment

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Building Simulation 2024年第10期17卷 1749-1765页

作者： Cong Song xiaohui li Yanfeng liu Longxiang Gao State Key Laboratory of Green Building Xi’an University of Architecture and TechnologyXi’anShaanxi 710055China School of Building Services Science and Engineering Xi’an University of Architecture and TechnologyXi’anShaanxi 710055China

About 1/3 of human life is spent *** hypoxic and cold environment in high-altitude areas leads to sleep disorders that are more prominently harmful to the human *** improve the quality of human sleep in high-altitude areas,this study explored the thermal and oxygen environment regulation for plateau *** this study,the influencing factors of the diffusion of oxygenic–thermal coupled airflow were determined through the theoretical analysis of a thermal fluid mechanic *** study used computational fluid dynamics(CFD)to investigate the diffusion characteristics of the oxygenic–thermal coupled airflow with a sleeping experiment conducted on the *** results showed that the influence of the thermal plume at 0.1 m near the human face was larger,and the oxygenic–thermal coupled airflow diffusion process was mainly divided into three phases over *** size and time to stabilize the oxygen volume fraction in the inhalation zone varied between conditions and were strongly influenced by the temperature difference of the supply *** effects of the thermal and oxygen environment were analyzed using indicators such as facial-area speed ratio,draft risk,and personal oxygen inhalation *** optimal design strategies were recommended with an outlet air velocity of 1.5 m/s,a temperature difference of 8 K between the outlet airflow and the indoor background air,and an outlet oxygen volume fraction of 30%.The results can provide implications for regulating the thermal and oxygen environment to improve human sleep quality in high-altitude areas.

关键词： high altitudes oxygenic–thermal coupled airflow sleep environment CFD method

Distribution of calcium, nickel, iron, and manganese in super-heavy oil from liaohe Oilfield, China

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Petroleum Science 2014年第4期11卷 590-595页

作者： Wu Bencheng Zhu Jianhua li xiaohui College of Chemical Engineering China University of Petroleum Beijing

liaohe super-heavy crude oil was separated into its components, namely saturates, aromatics, resins, and asphaltenes （SARA）, by the group separation method. Several solvents were used to extract different forms of metallic elements from crude oil. The metallic elements, such as calcium, nickel, iron and manganese, in crude oil, SARA and extract samples were analyzed by inductively coupled plasma atomic emission spectroscopy （ICP-AES）. The results demonstrate that the contents of calcium, nickel, iron, and manganese gradually increase in saturates, aromatics, resins, and asphaltenes, suggesting that the abundance of the four metallic elements in asphaltenes is much higher than that in the other groups. For example, the content of calcium in asphaltenes reaches a maximum of 7,920 pg/g. Among the SARA components of liaohe super-heavy crude oil, resins account for more than 50 wt%, suggesting that the total amount of the four metallic elements are higher in the resin component than in other components. The four metallic elements mainly exist in the form of organic metallic compounds in crude oil. Further analysis shows that calcium and manganese elements exist mainly as metal salts of petroleum acids, and the majority of the iron and all the nickel exist mainly as metalloporphyrin and non-metalloporphyrin compounds.

关键词： Super-heavy oil metallic element distribution group separation solvent extraction

^(40)Ar/^(39)Ar geochronology of the Faku tectonites:Implications for the tectonothermal evolution of the Faku block,northern liaoning

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Science China Earth Sciences 2005年第5期48卷 601-612页

作者： ZHANG xiaohui WANG Hui li Tiesheng Key Laboratory of lithosphere Tectonic Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Key Laboratory of Lithosphere Tectonic Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Key Laboratory of Lithosphere Tectonic Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

For lack of reliable isotopic chronological data, the metamorphic rock series in the Faku region of northern liaoning has long been regarded as the platform basement. Recent studies reveal that these deformed and metamorphosed rocks, with a variety of protoliths of plutonic intrusions and supracrustal volcanic and sedimentary rocks, were genetically related to later ductile shearing events, and they, together with the syntectonic intrusions, constituted the large-scale Faku tectonites. In this paper, we report new 40Ar/39Ar data on hornblende, biotite, and K-feldspar from typical granitic mylonites in this suite of tectonites. The plateau age 256 Ma of FK53 hornblende and the high-temperature plateau age 262 Ma of Fk51-1 biotite should rep- resent the cooling ages when the granites, formed as a result of Paleozoic oceanic crustal sub- duction beneath the continental crust or collision of multiple micro-continental blocks, were ex- humed into shallow crustal levels. The plateau age 231 Ma of FK51-1 boitite and the apparent age 227 Ma of Fk51-2 K-feldspar are interpreted to record the time of ductile deformation occur- ring under greenschist facies conditions, i.e. the formation age of the Faku tectonites, while the age gradient from 197 Ma to 220 Ma of Fk51-2 K-feldspar probably record the subsequent stable uplift-cooling process. The tectonic exhumation event indicated by the plateau age 180 Ma of Fk51-2 K-feldspar may be associated with the onset of paleo-Pacific subduction beneath the North China plate. In addition, the U-Pb dating of FK54 zircon from later-intruded granite yields the age of crystallization of this super-unit intrusion at 159 Ma, thus establishing an upper limit for the formation age of the Faku tectonites, while the plateau age 125 Ma of Fk54 K-feldspar most likely corresponds to the rapid cooling and tectonic denudation event associated with the final collision between the Siberian plate and the North China plate. These isotopic ages provide im-

关键词： northern liaoning, tectonite, 40Ar/39Ar age, zircon U-Pb age, Faku Faulted Convex.

A Novel Framework for Object-Based Coding and Compression of Hyperspectral Imagery

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Chinese Journal of Electronics 2015年第2期24卷 300-305页

作者： ZHAO Chunhui li xiaohui REN Jinchang Stephen Marshall College of Information and Communication Engineering Harbin Engineering University Department of Electronic and Electrical Engineering University of Strathclyde

A novel object-based framework is proposed for HSI compression, where targets of interest are extracted and separately coded. With objects removed,the holes are filled with the background average to form a new but more homogenous background for better compression. An improved sparse representation with adaptive spatial support is proposed for target detection. By applying the proposed framework to 2D/3D DCT approaches,reconstructed images from conventional and proposed approaches are compared. Six criteria in three groups are employed for quantitative evaluations to measure the degree of data reduction, the distortion of reconstructed image quality and accuracy in target detection, respectively. Comprehensive experiments on two datasets are used for performance evaluation. It is found that the proposed approaches yield much improved results.

关键词： Hyperspectral imagery(HSI) Objectbased image compression Sparse representation Target detection Remote sensing

Improved Q-learning algorithm for load balance in millimeter wave backhaul networks

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The Journal of China Universities of Posts and Telecommunications 2018年第3期25卷 8-16页

作者： Meng Danfeng li xiaohui Pu Wenjuan State Key Laboratory of Integrated Service Networks Xidian University Collaborative Innovation Center of Information Sensing and Understanding Xidian University

With the intensive deployment of users and the drastic increase of traffic load, a millimeter wave （mmWave） backhaul network was widely investigated. A typical mmWave backhaul network consists of the macro base station （MBS） and the small base stations （SBSs）. How to efficiently associate users with the MBS and the SBSs for load balancing is a key issue in the network. By adding a virtual power bias to the SBSs, more users can access to the SBSs to share the load of the MBS. The bias values shall be set reasonably to guarantee the backhaul efficiency and the quality of service （QoS）. An improved Q-learning algorithm is proposed to effectively adjust the bias value for each SBS. In the proposed algorithm, each SBS becomes an agent with independent learning and can achieve the best behavior, namely the optimal bias value through a series of training. Besides, an improved behavior selection mechanism is adopted to improve the learning efficiency and accelerate the convergence of the algorithm. Finally, simulations conducted in the 60 GHz band demonstrate the superior performance of the proposed algorithm in backhaul efficiency and user outage probability.

关键词： millimeter wave backhaul networks load balance user association Q-learning

Multivariate Two-stage Adaptive-stacking Prediction of Regional Integrated Energy System

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Journal of Modern Power Systems and Clean Energy 2023年第5期11卷 1462-1479页

作者： Leijiao Ge Yuanliang li Jan Yan Yuanliang li Jiaan Zhang xiaohui li IEEE School of Electrical and Information Engineering Tianjin UniversityTianjin 300072China Concordia Institute for Information Systems Engineering Concordia UniversityMontrealQC H3G 1M8Canada School of Electrical and Engineering Hebei University of TechnologyTianjin 300401China Marketing Service Center State Grid Tianjin Electric Power CompanyTianjin 300302China

To reduce environmental pollution and improve the efficiency of cascaded energy utilization, regional integrated energy system(RIES) has received extensive attention. An accurate multi-energy load prediction is significant for RIES as it enables stakeholders to make effective decisions for carbon peaking and carbon neutrality goals. To this end, this paper proposes a multivariate two-stage adaptive-stacking prediction(M2ASP) framework. First, a preprocessing module based on ensemble learning is proposed. The input data are preprocessed to provide a reliable database for M2ASP, and highly correlated input variables of multi-energy load prediction are determined. Then, the load prediction results of four predictors are adaptively combined in the first stage of M2ASP to enhance generalization ability. Predictor hyper-parameters and intermediate data sets of M2ASP are trained with a metaheuristic method named collaborative atomic chaotic search(CACS) to achieve the adaptive staking of M2ASP. Finally, a prediction correction of the peak load consumption period is conducted in the second stage of M2ASP. The case studies indicate that the proposed framework has higher prediction accuracy, generalization ability, and stability than other benchmark prediction models.

关键词： Collaborative atomic chaotic search(CACS) multivariate two-stage adaptive-stacking prediction(M2ASP)framework prediction error correction regional integrated energy system(RIES)

Using ontology and rules to retrieve the semantics of disaster remote sensing data

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Journal of Systems Engineering and Electronics 2024年第5期35卷 1211-1218页

作者： DONG Yumin li Ziyang li Xuesong li xiaohui Key Laboratory of Quantitative Remote Sensing Information Technology Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China

Remote sensing data plays an important role in natural disaster ***,with the increase of the variety and quantity of remote sensors,the problem of“knowledge barriers”arises when data users in disaster field retrieve remote sensing *** improve this problem,this paper proposes an ontology and rule based retrieval(ORR)method to retrieve disaster remote sensing data,and this method introduces ontology technology to express earthquake disaster and remote sensing knowledge,on this basis,and realizes the task suitability reasoning of earthquake disaster remote sensing data,mining the semantic relationship between remote sensing metadata and *** prototype system is built according to the ORR method,which is compared with the traditional method,using the ORR method to retrieve disaster remote sensing data can reduce the knowledge requirements of data users in the retrieval process and improve data retrieval efficiency.

关键词： remote sensing data disaster ontology semantic reasoning