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An earth observation potential evaluation model and its application to SDG indicators

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International Journal of Digital Earth 2022年第1期15卷 1187-1203页

作者： Meng Jin Ming Lin Yufu Liu yuqi bai Department of Earth System Science Institute for Global Change StudiesMinistry of Education Ecological Field Station for East Asian Migratory BirdsTsinghua UniversityBeijing 100084China

Thousands of satellites and instruments are providing very unique long-term,refined,and diverse perception capabilities for the states and changes of the Earth's surface *** leveraging Earth Observation(EO)techniques in SDG monitoring in specific regions,an important prerequisite is to evaluate whether EO could meet user requirements in terms of spatial coverage,temporal frequency and observing variables or *** is highly expected to have a quantitative model that can not only represent EO capabilities and observation requirements but also evaluate the potential of EO capability to fulfil these *** paper first describes EO capabilities from the satellite's orbit,operation time,spatial resolution,revisit cycle,accessibility and observation relevance level to *** requirements and priorities are then derived from SDG ***,the potential model is established to match EO capabilities and user *** SDG 14.1.1 as an example,this model is capable of returning an ordered list of satellites and instruments for users to refer *** model meets the gap of evaluating EO potential to fulfil SDG *** could make full use of the available EO capabilities worldwide to meet SDG indicator monitoring requirements.

关键词： Earth Observation remote sensing Sustainable Development Goals

GEOSatDB:global civil earth observation satellite semantic database

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Big Earth Data 2024年第3期8卷 522-539页

作者： Ming Lin Meng Jin Juanzi Li yuqi bai Department of Earth System Science Institute for Global Change StudiesMinistry of Education Ecological Field Station for East Asian Migratory BirdsTsinghua UniversityBeijingChina Department of Computer Science and Technology Tsinghua UniversityBeijingChina Tsinghua Urban Institute Tsinghua UniversityBeijingChina

Satellite remote sensing,characterized by extensive coverage,fre-quent revisits,and continuous monitoring,provides essential data support for addressing global *** the past six decades,thousands of Earth observation satellites and sensors have been deployed *** valuable Earth observation assets are contributed independently by various nations and organizations employing diverse *** poses a significant challenge in effectively discovering global Earth observation resources and realizing their full *** this paper,we describe the develop-ment of GEOSatDB,the most complete semantic database of civil Earth observation satellites developed based on a unified ontology model.A similarity matching method is used to integrate satellite information and a prompt strategy is used to extract unstructured sensor *** resulting semantic database contains 127,949 semantic statements for 2,340 remote sensing satellites and 1,021 observation *** global Earth observation capabil-ities of 195 countries worldwide have been analyzed in detail,and a concrete use case along with an associated query demonstration is *** database provides significant value in effectively facilitating the semantic understanding and sharing of Earth observa-tion resources.

关键词： Earth observation satellite sensor semantic representation information extraction

Satellite and instrument entity recognition using a pre-trained language model with distant supervision

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International Journal of Digital Earth 2022年第1期15卷 1290-1304页

作者： Ming Lin Meng Jin Yufu Liu yuqi bai Department of Earth System Science Institute for Global Change StudiesMinistry of Education Ecological Field Station for East Asian Migratory BirdsTsinghua UniversityBeijingPeople’s Republic of China

Earth observations,especially satellite data,have produced a wealth of methods and results in meeting global challenges,often presented in unstructured texts such as papers or *** extraction of satellite and instrument entities from these unstructured texts can help to link and reuse Earth observation *** direct use of an existing dictionary to extract satellite and instrument entities suffers from the problem of poor matching,which leads to low *** this study,we present a named entity recognition model to automatically extract satellite and instrument entities from unstructured *** to the lack of manually labeled data,we apply distant supervision to automatically generate labeled training ***,we fine-tune the pre-trained language model with early stopping and a weighted cross-entropy loss *** propose the dictionary-based self-training method to correct the incomplete annotations caused by the distant supervision *** demonstrate that our method achieves significant improvements in both precision and recall compared to dictionary matching or standard adaptation of pre-trained language models.

关键词： Earth observation named entity recognition pre-trained language model distant supervision dictionary-based self-training

Hydrolysis of cellobiose catalyzed by zeolites—the role of acidity and micropore structure

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Journal of Energy Chemistry 2016年第1期25卷 141-145页

作者： Lipeng Zhou Zhen Liu yuqi bai Tianliang Lu Xiaomei Yang Jie Xu College of Chemistry and Molecular Engineering Zhengzhou University School of Chemical Engineering and Energy Zhengzhou University State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences

The roles of acidity and micropore structure of zeolite were studied in the hydrolysis of the model oligosaccharide of cellulose–cellobiose. HZSM-5, HY, HMOR and Hβ zeolites were selected as model catalysts for the hydrolysis of cellobiose. The effect of acidity of zeolite, including the strength, type and location, on its catalytic activity was investigated. The strong Br？nsted acid sites located in micropores are the active sites for the hydrolysis of cellobiose to glucose. Meanwhile, the catalytic performance of zeolite is also dependent on the micropore size of zeolite.

关键词： Zeolites Biomass Cellulose Hydrolysis Acidity

Using a skillful statistical model to predict September sea ice covering Arctic shipping routes

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Acta Oceanologica Sinica 2020年第5期39卷 11-25页

作者： Sha Li Muyin Wang Wenyu Huang Shiming Xu Bin Wang yuqi bai Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing 100084China Joint Institute for the Study of the Atmosphere and Ocean University of WashingtonSeattle WA98195USA Pacific Marine Environmental Laboratory National Oceanic and Atmospheric AdministrationSeattle WA98115USA State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

The rapid decrease in Arctic sea ice cover and thickness not only has a linkage with extreme weather in the midlatitudes but also brings more opportunities for Arctic shipping routes and polar resource exploration,both of which motivate us to further understand causes of sea-ice variations and to obtain more accurate estimates of seaice cover in the ***,a novel data-driven method,the causal effect networks algorithm,is applied to identify the direct precursors of September sea-ice extent covering the Northern Sea Route and Transpolar Sea Route at different lead times so that statistical models can be constructed for sea-ice *** whole study area was also divided into two parts:the northern region covered by multiyear ice and the southern region covered by seasonal *** forecast models of September sea-ice extent in the whole study area(TSIE)and southern region(SSIE)at lead times of 1–4 months can explain over 65%and 79%of the variances,respectively,but the forecast skill of sea-ice extent in the northern region(NSIE)is limited at a lead time of 1 *** lead times of 1–4 months,local sea-ice concentration and sea-ice thickness have a larger influence on September TSIE and SSIE than other teleconnection *** the lead time is more than 4 months,the surface meridional wind anomaly from northern Europe in the preceding autumn or early winter is dominant for September TSIE variations but is comparable to thermodynamic factors for NSIE and *** suggest that this study provides a complementary approach for predicting regional sea ice and is helpful in evaluating and improving climate models.

关键词： regional sea ice Arctic shipping routes machine learning statistical model predictions

A traceability analysis system for model evaluation on land carbon dynamics: design and applications

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Ecological Processes 2021年第1期10卷 170-183页

作者： Jian Zhou Jianyang Xia Ning Wei Yufu Liu Chenyu Bian yuqi bai Yiqi Luo Zhejiang Tiantong Forest Ecosystem National Observation and Research Station Shanghai Key Lab for Urban Ecological Processes and Eco-RestorationSchool of Ecological and Environmental SciencesEast China Normal UniversityShanghai 200241China. Research Center for Global Change and Ecological Forecasting East China Normal UniversityShanghai 200241China. Ministry of Education Key Laboratory for Earth System Modelling Department of Earth System ScienceTsinghua UniversityBeijing 100084China. Joint Center for Global Change Studies(JCGCS) Beijing 100084China. Center for Ecosystem Science and Society Department of Biological SciencesNorthern Arizona UniversityFlagstaffArizonaUSA.

Background:An increasing number of ecological processes have been incorporated into Earth system ***,model evaluations usually lag behind the fast development of models,leading to a pervasive simulation uncertainty in key ecological processes,especially the terrestrial carbon(C)*** analysis provides a theoretical basis for tracking and quantifying the structural uncertainty of simulated C storage in ***,a new tool of model evaluation based on the traceability analysis is urgently needed to efficiently diagnose the sources of inter-model variations on the terrestrial C cycle in Earth system ***:A new cloud-based model evaluation platform,i.e.,the online traceability analysis system for model evaluation(TraceME v1.0),was *** TraceME was applied to analyze the uncertainties of seven models from the Coupled Model Intercomparison Project(CMIP6).Results:The TraceME can effectively diagnose the key sources of different land C dynamics among CMIIP6 *** example,the analyses based on TraceME showed that the estimation of global land C storage varied about 2.4 folds across the seven CMIP6 *** all models,IPSL-CM6A-LR simulated the lowest land C storage,which mainly resulted from its shortest baseline C residence *** the historical period of 1850–2014,gross primary productivity and baseline C residence time were the major uncertainty contributors to the inter-model variation in ecosystem C storage in most land grid ***:TraceME can facilitate model evaluation by identifying sources of model uncertainty and provides a new tool for the next generation of model evaluation.

关键词： CMIP6 land carbon cycle model evaluation traceability analysis uncertainty

Resilient Consensus of Second-order Discrete-time Multi-agent Systems Under Malicious Attack

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Resilient Consensus of Second-order Discrete-time Multi-agen...

第40届中国控制会议

作者： yuqi bai Jinzhi Wang College of Engineering Peking University

In this paper, we address resilient consensus of second-order discrete-time multi-agent systems with malicious agent that updates its value arbitrarily. Two kinds of attack forms（f-local and f-total） are presented. Under certain graph robustness condition, the proposed resilient algorithm could guarantee that all normal agents are not affected by the malicious agents to reach an agreement, and the final consensus value lies in a safety interval. Some numerical examples are finally given to demonstrate the validity of theoretical results.

关键词： multi-agent systems attack malicious agents resilient consensus algorithm

来源： cnki会议评论

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全球变化科学领域的信息基础设施研究

地球信息科学学报 2013年第6期15卷 809-813页

作者：白玉琪清华大学地球系统科学研究中心地球系统数值模拟教育部重点实验室北京100084

全球变化科学领域面临着体量巨大、增量迅速、种类繁多的观测数据和模拟数据的挑战,亟需新的研究思路和技术手段,实现数据的有效管理和分析,提高科学发现的效率。本文建议围绕科学数据、科研过程、学科交叉和国际国内合作4条主线开展全... 详细信息

全球变化科学领域面临着体量巨大、增量迅速、种类繁多的观测数据和模拟数据的挑战,亟需新的研究思路和技术手段,实现数据的有效管理和分析,提高科学发现的效率。本文建议围绕科学数据、科研过程、学科交叉和国际国内合作4条主线开展全球变化科学领域的信息基础设施研究。该项研究需要理解该领域不同学科方向的科学数据,挖掘它们在概念、空间、时间、量纲、格式、编码等方面的联系,建立统一的数据概念模型;需要分析该领域不同学科方向的研究全过程,分析不同过程、阶段之间的共性,建立统一的研究过程模型;需要在"数据-方法-模型-系统-标准"5个层面开展学科之间的共享和集成,建立统一的数据逻辑模型和物理模型、方法库、模型库、集成系统和标准体系;需要发展国际国内的合作伙伴,践行开放共享的共建方案。本文最后概要介绍了这一理念的GlobalChangeOne研究项目的总体设计,以及在遥感科学、生态科学、大气科学、地球系统模式、计算地球系统科学等学科方向的具体研究进展。该项研究有助于促进全球变化科学领域多学科间的交叉研究,有助于提高该领域的科学研究工作的效率,有助于建成全球变化与可持续发展研究全球共享的一体化基础平台。

关键词：全球变化可持续发展信息基础设施学科交叉科学研究效率

Molecular wakes for ultrashort laser pulses

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Science China(Physics,Mechanics & Astronomy) 2010年第6期53卷 1036-1039页

作者： CAI Hua,WU Jian,LU PeiFen,TONG yuqi,YANG Xuan,bai XueShi,LI Hao,PAN HaiFeng & ZENG HePing State Key Laboratory of Precision Spectroscopy,East China Normal University,Shanghai 200062,China State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai China

The molecular wake-assisted interaction between two collinear femotosecond laser pulses is investigated in air,which leads to the generation of a controllable 1.8 mJ super-continuum pulse with an elongated self-guided channel due to the cross-phase modulation of the impulsively aligned diatomic molecules in air. For two parallel launched femtosecond laser pulses with a certain spatial separation,controllable attraction and repulsion of the pulses are observed due to the counter-balance among molecular wakes,Kerr and plasma effects,where the molecular wakes show a longer interaction distance than the others to control the propagation of the intense ultrashort laser pulses.

关键词： molecular wakes ultrashort laser pulse interaction super-continuum generation