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Blockchain-Based MCS Detection Framework of Abnormal Spectrum Usage for Satellite Spectrum Sharing Scenario

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China Communications 2024年第2期21卷 32-48页

作者： ning yang Heng Wang Jingming Hu Bangning Zhang Daoxing Guo Yuan Liu College of Communications Engineering Army Engineering UniversityNanjing 210007China

In this paper, the problem of abnormal spectrum usage between satellite spectrum sharing systems is investigated to support multi-satellite spectrum coexistence. Given the cost of monitoring, the mobility of low-orbit satellites, and the directional nature of their signals, traditional monitoring methods are no longer suitable, especially in the case of multiple power level. Mobile crowdsensing(MCS), as a new technology, can make full use of idle resources to complete a variety of perceptual tasks. However, traditional MCS heavily relies on a centralized server and is vulnerable to single point of failure attacks. Therefore, we replace the original centralized server with a blockchain-based distributed service provider to enable its security. Therefore, in this work, we propose a blockchain-based MCS framework, in which we explain in detail how this framework can achieve abnormal frequency behavior monitoring in an inter-satellite spectrum sharing system. Then, under certain false alarm probability, we propose an abnormal spectrum detection algorithm based on mixed hypothesis test to maximize detection probability in single power level and multiple power level scenarios, respectively. Finally, a Bad out of Good(BooG) detector is proposed to ease the computational pressure on the blockchain nodes. Simulation results show the effectiveness of the proposed framework.

关键词： blockchain hypothesis test mobile crowdsensing satellite communication spectrum sharing

Effect of austenitizing condition on mechanical properties,microstructure and precipitation behavior of AISI H13 steel

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Journal of Iron and Steel Research(International) 2024年第1期31卷 143-156页

作者： An-gang ning yang Liu Rui Gao Stephen Yue Ming-bo Wang Han-jie Guo College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Department of Mining and Materials Engineering McGill UniversityMontrealQCH3A 0C5Canada ASSAB Tooling Technology(Chongqing)Co. Ltd.Chongqing401120China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China

The effects of austenitizing temperature(1223,1303,and 1373 K)and holding time(1-1500 s)on the microstructure,mechanical properties,and precipitation behavior of the H13 hot work die steel were investigated.The results indicate a softening phenomenon when H13 steel is austenitized at 1303 K beyond 900 s and 1373 K beyond 600 s,respectively.For the sample held for 1200 s,the tensile strength is found capable of reaching up to 2.2 GPa when quenched from a temperature above 1303 K.Meanwhile,prior-austenite grain size increases with the increase in austenitizing temperature.The kinetic behavior of the precipitates(mainly MC-type carbides)in H13 steel could be elaborated through the principles set forth by the Arrhenius and Avrami equations.Finally,the comprehensive strengthening of the H13 steel was discussed in detail.The results show that the activation energy of the transformed fraction of carbides is higher than that of the diffusion process for common alloying elements(Cr,V,Mo,and Ni)found in the austenite.This suggests that it would be difficult for precipitates to dissolve into the matrix when H13 steel is austenitized at high temperatures.With the increasing austenitizing temperature,the precipitation fraction decreases,and the dislocation density increases.The dislocation strengthening is regarded as the dominant strengthening contributed to yield strength in as-quenched H13 steel.

关键词： H13 steel Austenitizing Mechanical property Precipitation behavior Comprehensive strengthening

A Novel Clutter Suppression Algorithm for Low-Slow-Small Targets Detecting Based on Sparse Adaptive Filtering

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Journal of Beijing Institute of Technology 2024年第1期33卷 54-64页

作者： Zeqi yang Shuai Ma ning Liu Kai Chang Xiaode Lyu Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China National Key Laboratory of Microwave Imaging Technology Beijing 100190China School of Electronic Electrical and Communication Engineering University of Chinese Academy of SciencesBeijing 100049China Northern Institute of Electronic Equipment Beijing 100083China

Passive detection of low-slow-small(LSS)targets is easily interfered by direct signal and multipath clutter,and the traditional clutter suppression method has the contradiction between step size and convergence rate.In this paper,a frequency domain clutter suppression algorithm based on sparse adaptive filtering is proposed.The pulse compression operation between the error signal and the input reference signal is added to the cost function as a sparsity constraint,and the criterion for filter weight updating is improved to obtain a purer echo signal.At the same time,the step size and penalty factor are brought into the adaptive iteration process,and the input data is used to drive the adaptive changes of parameters such as step size.The proposed algorithm has a small amount of calculation,which improves the robustness to parameters such as step size,reduces the weight error of the filter and has a good clutter suppression performance.

关键词： passive radar interference suppression sparse representation adaptive filtering

Extreme value theory applied to the auroral electrojet indices

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Earth and Planetary Physics 2024年第2期8卷 375-381页

作者： Si Chen hong Yuan Yong Wei Guang yang FengZheng Yu Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The study of extreme weather and space events has gained paramount importance in modern society owing to rapid advances in high technology.Understanding and describing exceptional occurrences plays a crucial role in making decisive assessments of their potential impact on technical,economic,and social aspects in various fields.This research focuses on analyzing the hourly values of the auroral electrojet(AE)geomagnetic index from 1957 to 2019 by using the peak over threshold method in extreme value theory.By fitting the generalized Pareto distribution to extreme AE values,shape parameter indices were derived,revealing negative values that establish an upper bound for this time series.Consequently,it became evident that the AE values had reached a plateau,suggesting that extreme events exceeding the established upper limit are rare.As a result,although the need for diligent precautions to mitigate the consequences of such extreme events persists,surpassing the upper limit of AE values becomes increasingly challenging.It is also possible to observe an aurora in the middle-and low-latitude regions during the maximum period of the AE index.

关键词： auroral electrojet indices extreme value theory extreme events

Aberrant LETM1 elevation dysregulates mitochondrial functions and energy metabolism and promotes lung metastasis in osteosarcoma

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Genes & Diseases 2024年第3期11卷 368-384页

作者： Yulu Shi Quan Kang hong Zhou Xiaohan Yue yang Bi Qing Luo Stem Cell Biology and Therapy Laboratory The Children's Hospital of Chongqing Medical UniversityNational Clinical Research Center for Child Health and DisordersMinistry of Education Key Laboratory of Child Development and DisordersChongqing Key Laboratory of PediatricsChongqing 400014China Department of Pediatric Surgery The Children's Hospital of Chongqing Medical UniversityChongqing 400014China

Osteosarcoma is a differentiation-deficient disease,and despite the unique advan-tages and great potential of differentiation therapy,there are only a few known differentia-tion inducers,and little research has been done on their targets.Cell differentiation is associated with an increase in mitochondrial content and activity.The metabolism of some tu-mor cells is characterized by impaired oxidative phosphorylation,as well as up-regulation of aerobic glycolysis and pentose phosphate pathways.Leucine-containing zipper and EF-hand transmembrane protein 1(LETM1)is involved in the maintenance of mitochondrial morphology and is closely associated with tumorigenesis and progression,as well as cancer cell stemness.We found that MG63 and 143B osteosarcoma cells overexpress LETM1 and exhibit abnormalities in mitochondrial structure and function.Knockdown of LETM1 partially restored the mitochon-drial structure and function,inhibited the pentose phosphate pathway,promoted oxidative phosphorylation,and led to osteogenic differentiation.It also inhibited spheroid cell forma-tion,proliferation,migration,and invasion in an in vitro model.When LETM1 was knocked down in vivo,there was reduced tumor formation and lung metastasis.These data suggest that mitochondria are aberrant in LETM1-overexpressing osteosarcoma cells,and knockdown of LETM1 partially restores the mitochondrial structure and function,inhibits the pentose phosphate pathway,promotes oxidative phosphorylation,and increases osteogenic differentiation,thereby reducing malignant biological behavior of the cells.

关键词： Cancer metabolism Differentiation LETM1 Osteosarcoma Stemness

Combining reinforcement learning with mathematical programming:An approach for optimal design of heat exchanger networks

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Chinese Journal of Chemical Engineering 2024年第5期69卷 63-71页

作者： Hui Tan Xiaodong hong Zuwei Liao Jingyuan Sun Yao yang Jingdai Wang Yongrong yang State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 311215China

Heat integration is important for energy-saving in the process industry.It is linked to the persistently challenging task of optimal design of heat exchanger networks(HEN).Due to the inherent highly nonconvex nonlinear and combinatorial nature of the HEN problem,it is not easy to find solutions of high quality for large-scale problems.The reinforcement learning(RL)method,which learns strategies through ongoing exploration and exploitation,reveals advantages in such area.However,due to the complexity of the HEN design problem,the RL method for HEN should be dedicated and designed.A hybrid strategy combining RL with mathematical programming is proposed to take better advantage of both methods.An insightful state representation of the HEN structure as well as a customized reward function is introduced.A Q-learning algorithm is applied to update the HEN structure using theε-greedy strategy.Better results are obtained from three literature cases of different scales.

关键词： Heat exchanger network Reinforcement learning Mathematical programming Process design

Improved direct current electrical properties of XLPE modified by graftable antioxidant and crosslinking coagent at a wide temperature range

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High Voltage 2024年第1期9卷 94-104页

作者： Xu yang hong Zhao Chengcheng Zhang Chunyang Li Xindong Zhao Jiaming yang Xuan Wang Key Laboratory of Engineering Dielectrics and Its Application Harbin University of Science and TechnologyHarbinChina

To enhance the DC electrical performance of cross-linked polyethylene(XLPE),the graftable antioxidant methacrylic acid 2-hydroxy-3-(4-anilinoanilino)propyl ester(GA),which contains carbonyl and amino groups,and the crosslinking coagent trimethylolpropane trimethacrylate(TMPTMA),which contains carbonyl groups,are individually or co-grafted onto XLPE.The slightly higher deep trap density introduced by higher grafting concentration of TMPTMA results in more significant suppression effect of conductance current and enhanced breakdown strength at a lower temperature,while the suppression effect for the conductance current at 90°C becomes weakened due to limited trap energy.Meanwhile,the deeper energy level introduced by GA suppresses the conductance current and improves the electrical strength of XLPE at 90°C more significantly.By co-grafting,the conductance current of XLPE in a wide range temperature can be significantly reduced,especially for the temperature dependence of conductance current,which is beneficial to suppress the field strength reversal.The results of thermally stimulated current and molecular simulation show that the polar groups of two monomers introduce deep charge traps in XLPE.The co-grafting system ensures the rationality of the crosslinking reaction kinetics and does not affect the cable manufacturing.

关键词： crosslinking electrical grafting

Numerical and experimental study of the effects of wind turbine operation on sand-dust transport characteristics

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 97-113页

作者： Gaosheng Ma hong Han Ye Li Deshun Li Yan Wang ning Fu Quan Zheng Rennian Li School of Energy and Power Engineering Lanzhou University of TechnologyLanzhou 730050China Gansu Provincial Technology Center for Wind Turbines Lanzhou 730050China Key Laboratory of Fluid Machinery and Systems Lanzhou 730050China Multiple Function Towing Tank Laboratory State Key Laboratory of Ocean EngineeringSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Given factors such as reduced land availability for onshore wind farms,wind resource enrichment levels,and costs,there is a growing trend of establishing wind farms in deserts,the Gobi,and other arid regions.Therefore,the relationship between sanddust weather environments and wind turbine operations has garnered significant attention.To investigate the impact of wind turbine wakes on sand-dust transportation,this study employs large eddy simulation to model flow fields,coupled with an actuator line model for simulating rotating blades and a multiphase particle in cell model for simulating sand particles.The research focuses on a horizontal axis wind turbine model and examines the motion and spatiotemporal distribution characteristics of four typical sizes of sand particles in the turbine wake.The findings reveal that sand particles of varying sizes exhibit a spiral settling pattern after traversing the rotating plane of wind turbine blades,influenced by blade shedding vortex and gravity.Sand particles tend to cluster in the peripheries of the vortex cores of low vorticity in the wind turbine wake.The rotation of wind turbines generates a wake vortex structure that causes a significant clustering of sand particles at the tip vortex.As the wake distance increases,the particles that cluster at the turbine's tip gradually spread outward to approximately twice the rotor diameter and then begin to mix with the incoming flow environment.Wind turbines have a noticeable impact on sand-dust transportation,hindering their movement to a significant extent.The average sand-blocking rate exhibits a trend of initially increasing and then decreasing as the wake distance increases.At its peak,the sand-blocking rate reaches an impressive 67.55%.The presence of wind turbines induces the advanced settling of sand particles,resulting in a“triangular”distribution of the deposition within the ground projection area of the wake.

关键词： wind turbine particle transportation actuator line model dry deposition particle clustering

Two-person device-free localization system based on ZigBee and transformer

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High Technology Letters 2024年第1期30卷 61-67页

作者：刘天蒙 yang Hai xiao WU hong School of Electronic Information and Optical Engineering Nankai UniversityTianjin 300350P.R.China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Nankai UniversityTianjin 300350P.R.China Engineering Research Center of Thin Film Optoelectronics Technology Nankai UniversityTianjin 300350P.R.China

Most studies on device-free localization currently focus on single-person scenarios.This paper proposes a novel method for device-free localization that utilizes ZigBee received signal strength indication(RSSI)and a Transformer network structure.The method aims to address the limited research and low accuracy of two-person device-free localization.This paper first describes the construction of the sensor network used for collecting ZigBee RSSI.It then examines the format and features of ZigBee data packages.The algorithm design of this paper is then introduced.The box plot method is used to identify abnormal data points,and a neural network is used to establish the mapping model between ZigBee RSSI matrix and localization coordinates.This neural network includes a Transformer encoder layer as the encoder and a fully connected network as the decoder.The proposed method's classification accuracy was experimentally tested in an online test stage,resulting in an accuracy rate of 98.79%.In conclusion,the proposed two-person localization system is novel and has demonstrated high accuracy.

关键词： device-free localization deep learning ZigBee