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China Communications 2022年第2期19卷 118-130页

作者： long Suo Hongyan Li Shun Zhang Jiandong Li state key laboratory of Integrated service Networks Xidian UniversityXi’an 710071China Guangzhou Institute of Technology Xidian UniversityGuangzhou 510000China

Recently cellular networks have been densely and heterogeneously deployed indoors and outdoors to expand the network capacity,and thus the in-building propagation loss and the transmit power diversity of access points will exacerbate link heterogeneity and result in partial unidirectional strong *** make full use of the strong interference feature,we propose the successive interference cancellation and alignment(SICA)scheme in the K-user interference channel with partial unidirectional strong *** is designed to transmit two kinds of data streams simultaneously,the alignment streams and superposition *** alignment streams will follow the interference alignment criterion to maintain the optimal degrees of freedom(DoF)performance;the superposition streams are handled via successive interference cancellation at all the strongly interfered receivers to improve the overall achievable *** joint transceiver designs for SICA is modeled as a weighted sum rate(WSR)maximization problem,and then can be alternately solved for a local optimum according to the optimality equivalence between WSR and its corresponding weighted mean square error(WMMSE)*** results have confirmed the sum rate improvement and DoF optimality of the proposed SICA scheme.

关键词： interference alignment successive interference cancellation interference management ultra dense networks

An Efficient Correlation-Aware Anomaly Detection Framework in Cellular Network

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China Communications 2022年第8期19卷 168-180页

作者： Haihan Nan Xiaoyan Zhu Jianfeng Ma state key laboratory of Integrated service Networks Xidian UniversityXi’an 710071China School of Cyber Engineering Xidian UniversityXi’an 710071China

Nowadays,the fifth-generation(5G)mobile communication system has obtained prosperous development and deployment,reshaping our daily ***,anomalies of cell outages and congestion in 5G critically influence the quality of experience and significantly increase operational *** several big data and artificial intelligencebased anomaly detection methods have been proposed for wireless cellular systems,they change distributions of the data and ignore the relevance among user activities,causing anomaly detection ineffective for some *** this paper,we propose a highly effective and accurate anomaly detection framework by utilizing generative adversarial networks(GAN)and long short-term memory(LSTM)neural *** framework expands the original dataset while simultaneously keeping the distribution of data unchanged,and explores the relevance among user activities to further improve the system *** results demonstrate that our framework can achieve 97.16%accuracy and 2.30%false positive rate by utilizing the correlation of user activities and data expansion.

关键词： cellular network anomaly detection generative adversarial networks(GAN) long short-term memory(LSTM) call detail record(CDR)

The first quantitative joint observation of typhoon by Chinese GF-3 SAR and HY-2A microwave scatterometer

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Acta Oceanologica Sinica 2017年第11期36卷 1-3页

作者： LIN Mingsen YE Xiaomin YUAN Xinzhe National Satellite Ocean Application service State Oceanic Administration key laboratory of Space Ocean Remote Sensing and Application State Oceanic Administration laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology

The typhoon, as a mature tropical cyclone that develops in the western part of the North Pacific Ocean with high wind speed and heavy rainfall, is one of the most lethal and costly of natural disasters for the densely populated countries of East Asia. It can be easily detected by space-borne sensors operated at microwave, visible or infrared bands （Liu et al., 2014）. Synthetic Aperture Radar （SAR） is a kind of active imaging radar, which can detect the targets with high resolution at one-meter level. SARs can be used to extract the sea surface wind and the eyes of typhoons or hurricanes （Friedman and Li, 2000; Zhang and Perrie, 2012; Li, 2015; Jin et al., 2014; Liu et al., 2014）. As a pioneer project of Haiyang-3 （HY-3）, the Chinese C-band SAR satellite of Gaofen-3 （GF-3） was launched in August 2016 under China High-resolution Earth Observation System （CEOS）. GF-3 carries a multi-polarized C-band SAR with a highest spatial resolution of one meter, the most imaging modes in the word of twelve and a long designed lifespan of 8 years. Haiyang-2A （HY-2A）, which was launched in August 2011, is the first Chinese marine dynamic environment satellite with a main payload of Ku-band microwave scatterometer （Jiang et al., 2012; Ye et al., 2015）. One of the objectives of HY-2A scatterometer （HY-2A SCAT） is monitoring sea surface wind field of global ocean.

关键词： SAR The first quantitative joint observation of typhoon by Chinese GF-3 SAR and HY-2A microwave scatterometer GF HY

A Time-dependent Stochastic Grassland Fire Ignition Probability Model for Hulun Buir Grassland of China

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Chinese Geographical Science 2013年第4期23卷 445-459页

作者： GUO Zhixing FANG Weihua TAN Jun SHI Xianwu Academy of Disaster Reduction and Emergency Management Ministry of Civil Affairs & Ministry of Education National Marine Hazard Mitigation service State Oceanic Administration state key laboratory of Earth Surface Processes and Resource Ecology key laboratory of Environmental Change and Natural Disaster Ministry of Education

Grassland fire is one of the most important disturbance factors in the natural *** paper focuses on the spatial distribution of long-term grassland fire patterns in the Hulun Buir Grassland located in the northeast of Inner Mongolia Autonomous Region in *** density or ratio of ignition can reflect the relationship between grassland fire and different ignition *** on the relationship between the density or ratio of ignition in different range of each ignition factor and grassland fire events,an ignition probability model was developed by using binary logistic regression function and its overall accuracy averaged up to 81.7%.Meanwhile it was found that daily relative humidity,daily temperature,elevation,vegetation type,distance to county-level road,distance to town are more important determinants of spatial distribution of fire *** Monte Carlo method,we developed a time-dependent stochastic ignition probability model based on the distribution of inter-annual daily relative humidity and daily *** this model,it is possible to estimate the spatial patterns of ignition probability for grassland fire,which will be helpful to the quantitative evaluation of grassland fire risk and its management in the future.

关键词： grassland fire binary logistic regression GIS spatial analysis ignition probability Monte Carlo method

Semantic Region Estimation of Assistant Robot for the Elderly long-Term Operation in Indoor Environment

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China Communications 2016年第5期13卷 1-15页

作者： Guanglei Huo Lijun Zhao Ke Wang Ruifeng Li state key laboratory of Robotics and System Harbin Institute of Technology

In this work, in order to improve spatial recognition abilities for the long-term operation tasks of the assistant robot for the elderly, a novel approach of semantic region estimation is proposed. We define a novel graphbased semantic region descriptions, which are estimated in a dynamically fashion. We propose a two-level update algorithm, namely, Symbols update level and Regions update level. The algorithm firstly adopts particle filter to update weights of the symbols, and then use the Viterbi algorithm to estimate the region the robot stays in based on those weights, optimally. Experimental results demonstrate that our proposed approach can solve problems of the long-term operation and kidnapped robot problem.

关键词： service robot semantic region estimation particle filter viterbi algorithm long-term tasks

Centralized Dynamic Spectrum Allocation in Cognitive Radio Networks Based on Fuzzy Logic and Q-Learning

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China Communications 2011年第7期8卷 46-54页

作者：张文柱刘栩辰 state key laboratory of Integrated service Networks Xidian University

A novel centralized approach for Dynamic Spectrum Allocation (DSA) in the Cognitive Radio (CR) network is presented in this paper. Instead of giving the solution in terms of formulas modeling network environment such as linear programming or convex optimization, the new approach obtains the capability of iteratively on-line learning environment performance by using Reinforcement Learning (RL) algorithm after observing the variability and uncertainty of the heterogeneous wireless networks. Appropriate decision-making access actions can then be obtained by employing Fuzzy Inference System (FIS) which ensures the strategy being able to explore the possible status and exploit the experiences sufficiently. The new approach considers multi-objective such as spectrum efficiency and fairness between CR Access Points (AP) effectively. By interacting with the environment and accumulating comprehensive advantages, it can achieve the largest long-term reward expected on the desired objectives and implement the best action. Moreover, the present algorithm is relatively simple and does not require complex calculations. Simulation results show that the proposed approach can get better performance with respect to fixed frequency planning scheme or general dynamic spectrum allocation policy.

关键词： cognitive radio dynamic spectrum allocation fuzzy inference reinforce learning multi-objective

Time-Variant Reliability Analysis of FPSO Hull Girder Considering Corrosion Based on Statistics

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China Ocean Engineering 2007年第2期21卷 197-205页

作者：张道坤唐文勇张圣坤 state key laboratory of Ocean Engineering Shanghai Jiao Tong University

FPSO is a kind of important exploitation platform used in ocean oil and gas industry, which has the unique character of mooring at outsea for a long time. Since it can not be inspected and maintained thoronghly at dock like other kinds of ships, the reliability of FPSO hull girder during the whole service should be focused. Based on latest corrosion database and rational corrosion model, the ultimate strength of one FPSO is calculated under the conditions of slight, moderate and severe corrosion. The results not only provide the reliabihty under different corrosion conditions, but also do well for further inspection and maintenance research. The results provide necessary foundation for deciding inspection intervals and maintenance measure, which has practical sense to improve the general safety level of ocean engineering.

关键词： FPSO corrosion time-variant reliability analysis

Self-Floating Efficient Solar Steam Generators Constructed Using Super-Hydrophilic N,O Dual-Doped Carbon Foams from Waste Polyester

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Energy & Environmental Materials 2022年第4期5卷 1204-1213页

作者： Huiying Bai Ning Liu Liang Hao Panpan He Changde Ma Ran Niu Jiang Gong Tao Tang key laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective MaterialsSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China state key laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China

Solar evaporation is recognized as a prospective technique to produce freshwater from non-drinkable water using inexhaustible solar ***,it remains a challenge to fabricate low-cost solar evaporators with obviously reduced water evaporation enthalpy to achieve high evaporation ***,N,O dual-doped carbon foam(NCF)is fabricated from the lowtemperature carbonization of poly(ethylene terephthalate)(PET)waste by melamine/molten salts at 340℃.During carbonization,melamine reacts with carboxylic acids of PET degradation products to yield a crosslinking network,and then molten salts catalyze the decarboxylation and dehydration to construct a stable *** to rich N,O-containing groups,3D interconnected pores,super-hydrophilicity,and ultra-low thermal conductivity(0.0599 W m^(−1) K^(−1)),NCF not only achieves high light absorbance(ca.99%)and solar-to-thermal conversion,but also promotes the formation of water cluster to reduce water evaporation enthalpy by ca.37%.Consequently,NCF exhibits a high evaporation rate(2.4 kg m^(−2) h^(−1)),surpassing the-state-of-the-art solar evaporators,and presents good antiacid/basic abilities,long-term salt-resistance,and self-cleaning ***,a large-scale NCF-based outdoor solar desalination device is developed to produce *** daily freshwater production amount per unit area(6.3 kg)meets the two adults’daily water *** trash-to-treasure strategy will give impetus to the development of low-cost,advanced solar evaporators from waste plastics for addressing the global freshwater shortage.

关键词： carbon foam solar desalination solar energy solar steam generator waste plastics

Combined Impacts of Warm Central Equatorial Pacific Sea Surface Temperatures and Anthropogenic Warming on the 2019 Severe Drought in East China

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Advances in Atmospheric Sciences 2020年第11期37卷 1149-1163页

作者： Shuangmei MA Congwen ZHU Juan LIU state key laboratory of Severe Weather(LASW)and Institute of Climate System Chinese Academy of Meteorological SciencesBeijing 100081China Meteorological service Center of Zhejiang Hangzhou 310016China

A severe drought occurred in East China(EC)from August to October 2019 against a background of long-term significant warming and caused widespread impacts on agriculture and society,emphasizing the urgent need to understand the mechanism responsible for this drought and its linkage to global *** results show that the warm central equatorial Pacific(CEP)sea surface temperature(SST)and anthropogenic warming were possibly responsible for this drought *** warm CEP SST anomaly resulted in an anomalous cyclone over the western North Pacific,where enhanced northerly winds in the northwestern sector led to decreased water vapor transport from the South China Sea and enhanced descending air motion,preventing local convection and favoring a precipitation deficiency over *** simulations in the Community Earth System Model Large Ensemble Project confirmed the physical connection between the warm CEP SST anomaly and the drought in *** extremely warm CEP SST from August to October 2019,which was largely the result of natural internal variability,played a crucial role in the simultaneous severe drought in *** model simulations showed that anthropogenic warming has greatly increased the frequency of extreme droughts in *** indicated an approximate twofold increase in extremely low rainfall events,high temperature events,and concurrently dry and hot events analogous to the event in ***,the persistent severe drought over EC in 2019 can be attributed to the combined impacts of warm CEP SST and anthropogenic warming.

关键词： drought East China central equatorial Pacific SST global warming model simulations

Evaluation and adjustment of the radiometric degradation of HY-1B satellite COCTS via a stable marine site

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Geo-Spatial Information Science 2023年第3期26卷 321-332页

作者： Wenkai Li Guangping Xia Qingjun Song Ruqing Tong Liqiao Tian state key laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina Hubei LuoJia laboratory WuhanChina National Satellite Ocean Application service Ministry of Natural Resource of the People’s Republic of ChinaBeijingChina

The Chinese Ocean Color and Temperature Scanner(COCTS)on-board the Chinese second ocean color satellite,HY-1B,obtained approximately 6 years of data between 2007 and 2013 in China coastal seas and the adjacent ***,its radiometric performance has hardly been analyzed,which confuses its applicability in ocean remote *** study tracked the long-term radiometric responsivity trend of HY-1B COCTS based on a stable marine ***,we identified a temporally stable maritime site of 12°~15°N and 116°~119°E according to the water and atmospheric optical properties using Aqua MODIS ***,the time-series of top-of-atmosphere(TOA)reflectance was obtained for each band of HY-1B COCTS and Aqua MODIS over this site according to the criteria of sun-target-view ***,exponential or linear degradation models were built and used to adjust the radiometric levels of HY-1B *** indicate that the radiometric performance exhibited continuous degradation for all bands at varying levels between 0.4%and 8.1%yr^(−1).The worst degradation occurred at 412 nm,with an annual average rate of 8.1%.The degradation at 443 nm reached 5.5%yr^(−1)following 412 *** radiometric performance at 490 nm,520 nm,and 565 nm was relatively stable with a drift of~3%yr^(−1).The 670 nm,750 nm,and 865 nm bands remain most stable with the degradation of~1%yr^(−1).Taking Terra MODIS as a reference,the temporal consistency of HY-1B COCTS was significantly improved for each band after radiometric ***-free imageries between 2007 and 2013 showed relatively high spatial *** bias of TOA reflectance was~5%in visible bands and~10%in near-infrared bands after degradation *** improvements confirm the application potentials of HY-1B COCTS in ocean remote sensing.

关键词： HY-1B COCTS radiometric degradation stable marine site