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Science China(Technological Sciences) 2021年第11期64卷 2551-2559页

作者： ZHAO ShuFan SHEN XuHui LIAO Li ZEREN ZhiMa National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China Institute of Geophysics China Earthquake AdministrationBeijing 100081China

Over the last century, abnormal electromagnetic(EM) emissions associated with earthquake(EQ) activities have been widely reported and recorded by ground-based and satellite observations. The mechanism of extremely low-frequency(ELF) EM waves radiated from earthquakes has been gradually established. However, whether EM waves radiated from earthquakes can be detected by low Earth orbit(LEO) satellites remains controversial. In this paper, to address these concerns, a lithosphereatmosphere-ionosphere model of ELF wave propagation is constructed. The features of the simulated EM field at LEO satellite altitudes radiated from earthquakes have been studied. The simulated EM field at the altitude of the China Seismo-Electromagnetic Satellite(CSES) is compared with the sensitivity of electromagnetic(EM) sensors onboard the CSES. The results illustrate that an earthquake with a magnitude over 6.0 can be detected by the EM sensors of the CSES. However, this depends on the focal depth, seismogenic environment and ionospheric parameters.

关键词： earthquakes CSES satellite sensitivity trans-lithosphere-atmosphere-ionosphere ELF wave propagation model

A Novel Methodological Approach to Estimate the Impact of Natural Hazard-Induced Disasters on Country/Region-Level Economic Growth

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International Journal of Disaster Risk Science 2018年第1期9卷 74-85页

作者： Sayanti Mukherjee Makarand Hastak Lyles School of Civil Engineering Purdue University School of Industrial Engineering Purdue University Division of Construction Engineering and management Purdue University

With the increased frequency of extreme weather events and large-scale disasters, extensive societal and economic losses incur every year due to damage of infrastructure and private properties, business disruptions,fatalities, homelessness, and severe health-related issues. In this article, we analyze the economic and disaster data from1970 through 2010 to investigate the impact of disasters on country/region-level economic growth. We leveraged a random parameter modeling approach to develop the growth-econometrics model that identifies risk factors significantly influencing the country/region-level economic growth in the face of natural hazard-induced disasters,while controlling for country/region-and time-specific unobserved heterogeneities. We found that disaster intensity in terms of fatalities and homelessness, and economic characteristics such as openness to trade and a government's consumption share of purchasing power parity(PPP), are the significant risk factors that randomly vary for different countries/regions. Other significant factors found to be significant include population, real gross domestic product(GDP), and investment share of PPP converted GDP per capita. We also found that flood is the most devastating disaster to affect country/region-level economic growth. This growth-econometrics model will help in the policy and decision making of governmentsrelated to the investment needs for pre-and post-disaster risk mitigation and response planning strategies, to better protect nations and minimize disaster-induced economic impacts.

关键词： Disaster risk reduction Economic growth Growth econometrics Impact of natural hazard-induced disasters Panel data analysis Random parameter modeling

From active fault segmentation to risks of earthquake hazards and property and life losses—A case study from the Xianshuihe-Xiaojiang fault zone

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Science China Earth Sciences 2023年第6期66卷 1345-1364页

作者： Jia CHENG Chong XU Jian MA Xiwei XU Pengyu ZHU National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China Key Laboratory of Compound and Chained Natural Hazards Dynamics Ministry of Emergency Management of ChinaBeijing 100085China Institute of Engineering Mechanics China Earthquake AdministrationHarbin 150080China School of Earth Sciences and Resources China University of Geosciences(Beijing)Beijing 100083China

Strong earthquakes generally rupture along active faults,and associated ground motion can cause earthquake disasters,property losses,and casualties from kilometers to tens of kilometers ***,one of the most effective ways to find earthquake’s dangerous parts of faults is to study the seismic hazards on fault *** that,we can also evaluate the probabilities of landslides hazard,property losses,and *** this study,using fault slip rates and magnitude-frequency relationship as constraints,we calculated the earthquake occurrence rates for the segments along the Xianshuihe-Xiaojiang fault *** obtained 11 sites of single-segment or multi-segment rupturing *** also provided these potential events conditional probabilities in the next 30 *** the 11 potential earthquakes,we calculated the property loss of residential buildings in the ground motion *** most significant property loss is CNY 7.65 billion caused by the single-segment rupturing of the F19 segment on the Anninghe *** applied the deep learning neural network method in predicting the number of casualties for the potential earthquakes,showing that the most significant event is the multi-segment rupturing of the F29 and F30 segments on the Anninghe fault with the predicted death number of *** also evaluated the probabilities of earthquake landslides after the potential *** results show that areas with intense compressional tectonic stress are highly unstable and prone to earthquake induced landslides,including the southern section of the Yuke fault,the southern section of the Xianshuihe fault,and the conjugated area between the southern section of the Daliangshan fault and the Lianfeng *** areas have a considerable number of earthquake landslides with probabilities>10%.The methodology and results will give us a new effective way of applying active fault data in earthquake hazard and risk analysis and provide a scientific path for earthqua

关键词： Xianshuihe-Xiaojiang fault Fault segmentation Multi-segment rupture Probabilities of landslide Property losses

Towards an Esox lucius inspired multimodal robotic fish

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Science China(Information Sciences) 2015年第5期58卷 182-194页

作者： WU ZhengXing YU JunZhi SU ZongShuai TAN Min LI ZhenLong State Key Laboratory of management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences College of Electronic Information and Control Engineering Beijing University of Technology

In this paper, we further explore multimodal locomotion via an updated robotic fish model based on Esox lucius. Besides the improved actuation properties like higher torque servomotors and powerful electronics,the robotic fish has some innovative mechanical design to pursue diverse swimming modes and superior performance. Specifically, we introduced a ±50° yawing head joint that functions as the neck for enhancing turning ability. A pair of pectoral mechanisms with two DOFs per fin is constructed to achieve 3-D swimming and to enrich multiple pectoral motions. At the control level, an improved central pattern generator(CPG) model allowing for free adjustment of the phase relationship among outputs is employed to produce rhythmic signals of multimodal swimming. Extensive experiments were carried out to examine how characteristic parameters in CPGs including amplitude, frequency, and phase lag affect the swimming performance. As a result, the robotic fish successfully performed various locomotion actions such as forward swimming, backward swimming, turning, diving, surfacing, as well as three pectoral motions in the form of pitching, heaving, and *** found that small phase lag between oscillating joints which means large propulsive body wave length and undulation width could lead to a faster swimming in body and/or caudal fin(BCF) locomotion.

关键词： bio-inspired robot robotic fish CPG multimodal swimming motion control

CitationAS： A Tool of Automatic Survey Generation Based on Citation Content

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Journal of Data and Information Science 2018年第2期3卷 20-37页

作者： jie wang chengzhi zhang mengying zhang sanhong deng School of Information management Nanjing University Nanjing 210023 China Department of Information management Nanjing University of Science and Technology Nanjing 210094 China Jiangsu Key Laboratory of Data Engineering and Knowledge Service Nanjing University Nanjing 210023 China

Purpose： This study aims to build an automatic survey generation tool, named CitationAS, based on citation content as represented by the set of citing sentences in the original ***/methodology/approach： Firstly, we apply LDA to analyse topic distribution of citation content. Secondly, in CitationAS, we use bisecting K-means, Lingo and STC to cluster retrieved citation content. Then Word2Vec, Word Net and combination of them are applied to generate cluster labels. Next, we employ TF-IDF, MMR, as well as considering sentence location information, to extract important sentences, which are used to generate surveys. Finally, we adopt manual evaluation for the generated ***： In experiments, we choose 20 high-frequency phrases as search terms. Results show that Lingo-Word2Vec, STC-Word Net and bisecting K-means-Word2Vec have better clustering effects. In 5 points evaluation system, survey quality scores obtained by designing methods are close to 3, indicating surveys are within acceptable limits. When considering sentence location information, survey quality will be improved. Combination of Lingo, Word2Vec, TF-IDF or MMR can acquire higher survey *** limitations： The manual evaluation method may have a certain subjectivity. We use a simple linear function to combine Word2Vec and Word Net that may not bring out their strengths. The generated surveys may not contain some newly created knowledge of some articles which may concentrate on sentences with no *** implications： CitationAS tool can automatically generate a comprehensive, detailed and accurate survey according to user’s search terms. It can also help researchers learn about research status in a certain ***/value： Citaiton AS tool is of practicability. It merges cluster labels from semantic level to improve clustering results. The tool also considers sentence location information when calculating sentence score by TF-IDF and MMR.

关键词： Automatic survey system Citation content Clustering algorithms Labelgeneration approaches Sentence extraction methods

Effects of altitude and slope on the climate–radial growth relationships of Larix olgensis *** in the southern Lesser Khingan Mountains,Northeast China

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Ecological Processes 2022年第1期11卷 618-630页

作者： Jingjing Qiao Yujun Sun National Forestry&Grassland Administration Key Laboratory of Forest Resources&Environmental management Beijing Forestry UniversityBeijing 100083China

Background:The relationship between climate and radial growth of trees exhibits spatial variation due to environ-mental ***,elucidation of how the growth–climate responses of trees vary in space is essential for understanding forest growth dynamics to facilitate scientific management with the ongoing global climate *** explore the altitudinal and slope variations of these interactions,tree-ring width chronologies of Larix olgensis *** were analyzed in the southern Lesser Khingan Mountains,Northeast ***:The radial growth of *** exhibited significant 5-to 10-year periodic changes at three altitudes and two slopes,and the frequency change occurred mainly during the early growth stage and after *** radial growth of *** was significantly negatively correlated with September precipitation only at low altitudes,but also with the mean temperature in July–August and the mean maximum temperature in June–August at high *** radial growth of *** at low and middle altitudes as well as on the sunny slope led to a higher demand for moisture,while temperature was the key limiting factor at high altitudes and on the shady ***:The climate–radial growth relationship of *** exhibits altitudinal and slope *** study quantitatively describes the spatially varying growth–climate responses of *** in the southern Lesser Khingan Mountains,which provides basic data for the management of *** forests and the prediction of future climate impacts on forest ecosystems.

关键词： Larix olgensis A.Henry Altitudinal gradient Slope variability Lesser Khingan Mountains

Sentiment Analysis of Japanese Tourism Online Reviews

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Journal of Data and Information Science 2019年第1期4卷 89-113页

作者： Chuanming Yu Xingyu Zhu Bolin Feng Lin Cai Lu An School of Information and Safety Engineering Zhongnan University of Economics and Law School of Information management Wuhan University

Purpose: Online reviews on tourism attractions provide important references for potential tourists to choose tourism spots. The main goal of this study is conducting sentiment analysis to facilitate users comprehending the large scale of the reviews, based on the comments about Chinese attractions from Japanese tourism website 4 ***/methodology/approach: Different statistics-and rule-based methods are used to analyze the sentiment of the reviews. Three groups of novel statistics-based methods combining feature selection functions and the traditional term frequency-inverse document frequency(TF-IDF) method are proposed. We also make seven groups of different rulesbased methods. The macro-average and micro-average values for the best classification results of the methods are calculated respectively and the performance of the methods are ***: We compare the statistics-based and rule-based methods separately and compare the overall performance of the two method. According to the results, it is concluded that the combination of feature selection functions and weightings can strongly improve the overall performance. The emotional vocabulary in the field of tourism(EVT), kaomojis, negative and transitional words can notably improve the performance in all of three categories. The rule-based methods outperform the statistics-based ones with a narrow *** limitation: Two limitations can be addressed: 1) the empirical studies to verify the validity of the proposed methods are only conducted on Japanese languages; and 2) the deep learning technology is not been incorporated in the *** implications: The results help to elucidate the intrinsic characteristics of the Japanese language and the influence on sentiment analysis. These findings also provide practical usage guidelines within the field of sentiment analysis of Japanese online tourism ***/value: Our research is of practicability. Currently, there are no stud

关键词： Sentiment analysis Japanese reviews Rule-based methods Statistics-based methods Tourism reviews

Non-spherical aluminum nanoparticles fabricated using picosecond laser ablation

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International Journal of Minerals,Metallurgy and Materials 2020年第7期27卷 980-986页

作者： A.Brahma Swamulu S.Venugopal Rao G.Krishna Podagatlapalli Department of Physics Rajiv Gandhi University of Knowledge TechnologiesNuzvidAndhra Pradesh 521202India Advanced Centre of Research in High Energy Materials(ACRHEM) University of HyderabadHyderabad 500046TelanganaIndia Department of Electronics&Physics Gandhi Institute of Technology and Management Institute of ScienceGandhi Institute of Technology and Management deemed to be UniversityVisakhapatnam 530045Andhra PradeshIndia

We report the picosecond laser ablation of aluminum targets immersed in a polar organic liquid(chloroform,CHCl3)with^2 ps laser pulses at an input energy of^350μ*** synthesized aluminum nanoparticles exhibited a surface plasmon resonance peak at^340 *** electron microscopy images of Al nanoparticles demonstrated the spherical morphology with an average size of(27±3.6)*** formation of smaller spherical Al nanoparticles and the diminished growth could be from the formation of electric double layers on the Al *** addition to spherical aluminum nanoparticles,triangular/pentagonal/hexagonal nanoparticles were also observed in the colloidal *** emission scanning electron microscopy images of ablated Al targets demonstrated laser induced periodic surface structures(LIPSSs),which were the high spatial frequency LIPSSs(HSF-LIPSSs)since their grating period was^280 ***,coarse structures with a period of^700 nm were observed.

关键词： ablation picosecond silver polar periodic surfaces electric double layers

An MA-MRR model for transaction-level analysis of highfrequency trading processes

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Journal of management Science and Engineering 2024年第1期9卷 53-61页

作者： Qiang Zhang Zudi Lu Shancun Liu Haijun Yang Jingrui Pan School of Economics and management Beijing University of Chemical TechnologyBeijing100029China Mathematical Sciences and Southampton Statistical Sciences Research InstituteUniversity of SouthamptonHighfieldSouthamptonSO171BJUK School of Economics and management Beihang UniversityBeijing100191China Key Laboratory of complex System Analysis Management and Decision(Beihang University)Ministry of EducationBeijing100191China

The transaction-level analysis of security price changes by Madhavan,Richardson,and Roomans(1997,hereafter MRR)is a useful framework for financial *** first-order Markov property of trading indicator variables is a critical assumption in the MRR model,which contradicts the information lag empirically demonstrated in high-frequency trading *** this study,a nonparametric test is employed,which shows that the Markov property of the trading indicator variables is rejected on most trading *** on the spread decomposed structure,an MA-MRR model was proposed with a moving average structure adopted to absorb the information lag as an *** empirical results show that the information lag plays an important role in measuring the adverse selection risk parameter and that the difference in this parameter between the original and the extension is ***,our analysis suggests that the information lag parameter is a useful measure of the average speed at which information is incorporated into prices.

关键词： Spread decomposition Adverse selection risk MA-MRR model Information lag

AN INTERVAL METHOD FOR STUDYING THE RELATIONSHIP BETWEEN THE AUSTRALIAN DOLLAR EXCHANGE RATE AND THE GOLD PRICE

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Journal of Systems Science & Complexity 2012年第1期25卷 121-132,132+131页

作者： Ai HAN K.K.LAI Shouyang WANG Shanying XU Academy of Mathematics and Systems Sciences Chinese Academy of Sciences Department of management Sciences City University of Hong KongTat Chee AvenueKowloonHong KongChina

This paper proposes an interval method to explore the relationship between the exchange rate of Australian dollar against US dollar and the gold price, using weekly, monthly and quarterly data. With the interval method, interval sample data are formed to present the volatility of variables. The ILS approach is extended to multi-model estimation and the computational schemes are provided. The empirical evidence suggests that the ILS estimates well characterize how the exchange rate relates to the gold price, both in the long-run and short-run. The comparison between the interval and point methods indicates that the difference between the OLS and the ILS estimates is increasing from weekly data to quarterly data, since the lowest frequency point data lost the most information of volatility.

关键词： Exchange rate gold price interval method.