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Analysis and application of automatic deformation monitoring data for buildings and structures of mining area

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中国有色金属学会会刊：英文版 2011年第S3期21卷 516-522页

作者： XIAO Jie1, 2, 3. ZHANG Jin4 1. Institute of geodesy and Geophysics, chinese academy of sciences, wuhan 43.077, China 2. {3. {3. of dynamic geodesy, Institute of geodesy and Geophysics, chinese academy of sciences, wuhan 43.077, China 3. Graduate School of chinese academy of sciences, Beijing 100049, China 4. Department of Surveying and Mapping, Taiyuan University of Technology, Taiyuan 03.024, China Institute of geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China key laboratory of dynamic {3. Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Graduate School of chinese academy of sciences Beijing 100049 China Department of Surveying and Mapping Taiyuan University of Technology Taiyuan 030024 China

The buildings and structures of mines were monitored automatically using modern surveying technology. Through the analysis of the monitoring data, the deformation characteristics were found out from three aspects containing points, lines and regions, which play an important role in understanding the stable state of buildings and structures. The stability and deformation of monitoring points were analysed, and time-series data of monitoring points were denoised with wavelet analysis and Kalman filtering, and exponent function and periodic function were used to get the ideal deformation trend model of monitoring points. Through calculating the monitoring data obtained, analyzing the deformation trend, and cognizing the deformation regularity, it can better service mine safety production and decision-making.

关键词： wavelet analysis Kalman filtering deformation monitoring data analysis mine

An ID-based authenticated dynamic group key agreement with optimal round

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Science China(Information sciences) 2012年第11期55卷 2542-2554页

作者： TENG JiKai1,2,WU ChuanKun1 & TANG ChunMing3.1State key laboratory of Information Security,Institute of Software of chinese academy of sciences,Beijing 100090,China 2Graduate University of chinese academy of sciences,Beijing 100049,China 3.aculty of Mathematic and Information Science,Guangzhou University,Guangzhou 510006,China State key laboratory of Information Security Institute of Software of Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Faculty of Mathematic and Information Science Guangzhou University Guangzhou China

Group key agreement protocols are crucial for achieving secure group *** are designed to provide a set of users with a shared secret key to achieve cryptographic goal over a public *** group membership changes,the session key should be refreshed efficiently and *** previous group key agreement protocols need at least two rounds to establish or refresh session *** this paper,a dynamic authenticated group key agreement(DAGKA) protocol based on identity-based cryptography is *** making use of the members' values stored in previous sessions,our Join and Leave algorithms reduce the computation and communication costs of *** the proposed protocol,Setup and Join algorithms need one *** session key can be refreshed without message exchange among remaining users in Leave algorithm,which makes the protocol more *** security is proved under decisional bilinear Diffie-Hellman(DBDH) assumption in random oracle model.

关键词： identity-based cryptography dynamic group key agreement provably secure admissible pairing

Validating global hydrological models by ground and space gravimetry

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chinese Science Bulletin 2009年第9期54卷 1534-1542页

作者： ZHOU JiangCun1,2,3. SUN HePing1,2 & XU JianQiao1,2 1 Institute of geodesy and Geophysics, chinese academy of sciences, wuhan 43.077, China {3., chinese academy of sciences, wuhan 43.077, China 3.Graduate University of chinese academy of sciences, Beijing 100049, China Institute of geodesy and Geophysics Chinese Academy of Sciences Wuhan China key laboratory of dynamic {3. Chinese Academy of Sciences Wuhan China Graduate University of chinese academy of sciences Beijing China

The long-term continuous gravity observations obtained by the superconducting gravimeters (SG) at seven globally-distributed stations are comprehensively analyzed. After removing the signals related to the Earth's tides and variations in the Earth's rotation, the gravity residuals are used to describe the seasonal fluctuations in gravity field. Meanwhile, the gravity changes due to the air pressure loading are theoretically modeled from the measurements of the local air pressure, and those due to land water and nontidal ocean loading are also calculated according to the corresponding numerical models. The numerical results show that the gravity changes due to both the air pressure and land water loading are as large as 100×10-9 m s-2 in magnitude, and about 10×10-9 m s-2 for those due to the nontidal ocean loading in the coastal area. On the other hand, the monthly-averaged gravity variations over the area surrounding the stations are derived from the spherical harmonic coefficients of the GRACE-recovered gravity fields, by using Gaussian smoothing technique in which the radius is set to be 600 km. Com-pared the land water induced gravity variations, the SG observations after removal of tides, polar mo-tion effects, air pressure and nontidal ocean loading effects and the GRACE-derived gravity variations with each other, it is inferred that both the ground- and space-based gravity observations can effec-tively detect the seasonal gravity variations with a magnitude of 100×10-9 m s-2 induced by the land water loading. This implies that high precision gravimetry is an effective technique to validate the re-liabilities of the hydrological models.

关键词：重力测量水文模型模型验证和空间地面重力变化季节性波动空气压力

Experimental earth tidal models in considering nearly diurnal free wobble of the Earth's liquid core

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Science Bulletin 2003年第9期48卷 935-940页

作者： SUN Heping, XU Jianqiao & B. Ducarme key laboratory of dynamic {3., Institute of {3. and Geophysics, chinese academy of sciences, wuhan 43.077, China Observatoire Royal de Belgique, Av. Circulaire 3. B-1180, Brussels, Belgium Correspondence should be addressed to Sun Heping (e-mail: heping@ ***) key laboratory of dynamic {3. Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Observatoire Royal de Belgique Av. Circulaire 3 B-1180 Brussels Belgium

Based on the 28 series of the high precision and high minute sampling tidal gravity observations at 20 stations in Global Geodynamics Project (GGP) network, the resonant parameters of the Earth's nearly diurnal free wobble (including the eigenperiods, resonant strengths and quality factots) are precisely determined. The discrepancy of the eigenperiod between observed and theoretical values is studied, the important conclusion that the real dynamic ellipticity of the liquid core is about 5% larger than the one under the static equilibrium assumption is approved by using our gravity technique. The experimental Earth's tidal gravity models with considering the nearly diurnal free wobble of the Earth's liquid core are constructed in this study. The numerical results show that the difference among three experimental models is less than 0.1%, and the largest discrepancy compared to those widely used nowdays given by Dehant (1999) and Mathews (2001) is only about 0.4%. It can provide with the most recent real

关键词： Earth’s nearly diurnal free wobble global observations of superconducting gravimeters dynamic ellipticity of liquid core experimental earth tidal models.

GRACE detection of the medium-to far-field coseismic gravity changes caused by the 2004 Mw9.3.Sumatra-Andaman earthquake

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Earthquake Science 2012年第3期25卷 235-240页

作者： Jin Li1,2,3.and Wenbin Shen1,3.4, 1 Department of Geophysics, School of geodesy and Geomatics, wuhan University, wuhan 43.079, China 2 {3. {3. of Geodynamic geodesy of chinese academy, wuhan 43.077, China 3.{3. {3. of Geospace Environment and geodesy (Ministry of Education), wuhan University, wuhan 43.079, China 4 State {3. {3. of Information Engineering in Surveying, Mapping and Remote Sensing, wuhan 43.079, China Department of Geophysics School of Geodesy and Geomatics Wuhan University Wuhan China key laboratory of Geodynamic {3. of {3. academy Wuhan China key laboratory of Geospace Environment and geodesy (Ministry of Education) Wuhan University Wuhan China State key laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan China

Large earthquakes cause observable changes in the Earth’s gravity field, which have been detected by the Gravity Recovery and Climate Experiment (GRACE). Since most previous studies focus on the detection of near-field gravity effects, this study provides the results from the medium- to far-field gravity changes caused by the 2004 Sumatra-Andaman earthquake that are recorded within GRACE monthly solutions. Utilizing a spherical-earth dislocation model we documented that large-scale signals predominate in the global field of the coseismic gravity changes caused by the earthquake. After removing the near-field effects, the coseismic gravity changes show a negative anomaly feature with an average magnitude of -0.18×10-8 m·s-2 in the region ranging ～40° from the epicenter, which is considered as the 'medium ffield' in this study. From the GRACE data released by Center for Space Research from August 2002 to December 2008, we retrieved the large-scale gravity changes smoothed with 3.000 km Gaussian ffilter. The results show that the coseismic gravity changes detected by GRACE in the medium field have an average of (-0.20±0.06)×10-8 m·s-2, which agrees with the model prediction. The detection confirms that GRACE is sensitive to large-scale medium-field coseismic gravitational effects of mega earthquakes, and also validates the spherical-earth dislocation model in the medium field from the perspective of satellite gravimetry.

关键词： GRACE medium-to far-field coseismic gravity change 2004 Sumatra-Andaman earthquake spherical-Earth dislocation model

A mixed method for measuring low-frequency acoustic properties of macromolecular materials

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Science China(Physics,Mechanics & Astronomy) 2006年第6期49卷 729-739页

作者： LIU Hongwei1,YAO Lei1,3.ZHAO Hong1,3.ZHANG Jichuan2,3.& XUE Zhaohong2 1. National key laboratory of Acoustics,Institute of Acoustics,chinese {3. of {3.,Beijing 100080,China 2. Institute of Chemistry,chinese {3. of {3.,Beijing 100080,China 3. Graduate University of chinese academy of sciences,Beijing 100049,China National key laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Institute of Chemistry Chinese Academy of Sciences Beijing China

A mixed method for measuring low-frequency acoustic properties of macro-molecular materials is presented. The dynamic mechanical parameters of materials are first measured by using dynamic Mechanical Thermal Apparatus(DMTA) at low frequen-cies,usually less than 100 Hz; then based on the Principles of Time-Temperature Super-position (TTS),these parameters are extended to the frequency range that acousticians are concerned about,usually from hundreds to thousands of hertz; finally the extended dynamic mechanical parameters are transformed into acoustic parameters with the help of acoustic measurement and inverse analysis. To test the feasibility and accuracy,we measure a kind of rubber sample in DMTA and acquire the basic acoustic parameters of the sample by using this method. While applying the basic parameters to calculating characteristics of the sample in acoustic pipe,a reasonable agreement of sound absorp-tion coefficients is obtained between the calculations and measurements in the acoustic pipe.

关键词： low-frequency acoustic properties,dynamic mechanical properties,Principles of Time-Temperature Superposition,acoustic pipe,sound absorption coefficient.

Determination of ocean tide loading displacements in Hong Kong using GPS technique

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Science China Earth sciences 2010年第7期53卷 993-1007页

作者： YUAN LinGuo1,3. DING XiaoLi1, SUN HePing2, ZHONG Ping1,3.& CHEN Wu1 1 Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China 2 key laboratory of dynamic geodesy, Institute of geodesy and Geophysics, chinese academy of sciences,{3., China 3.Department of Surveying Engineering, School of Civil Engineering, Southwest Jiaotong University, Chengdu 61003., China Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic University Kowloon Hong Kong China Department of Surveying Engineering School of Civil Engineering Southwest Jiaotong University Chengdu China key laboratory of dynamic {3. Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan China

Ocean tide loading (OTL) displacements of eight principal constituents at 12 sites in Hong Kong were determined using more than eight years of continuous GPS observations. Parameters of the OTL displacements were estimated using daily GPS solutions obtained with precise point positioning (PPP) technique. The results were compared with predictions from seven latest global ocean tide models. Gravity measurements of OTL in Hong Kong were also used to validate the GPS results. The study shows that the results from both the GPS and gravity measurements agree best with the GOT4.7 and NAO99b models, when the K1 and K2 constituents are excluded. The agreements between the GPS and the model estimates are generally at sub-millimeter level in both the horizontal and vertical directions, except for S2, K2 and K1 constituents that have relatively larger errors. After removing the systematic biases between the GPS and the model estimates, the misfits of M2, S2, N2, O1, P1 and Q1 at all sites are within 0.5 and 1.0 mm in the horizontal and the vertical directions, respectively, whereas K1 and K2 show relatively larger misfits of up to 2.3.mm. Both the GPS and the gravity S2 estimates have large biases with unknown reasons when compared with the modeled values, which needs to be further investigated. The study demonstrates that GPS is capable of estimating the OTL displacements with the same accuracy as the model predictions, especially for coastal areas.

关键词： GPS ocean tide loading ocean tide model site displacement

Influence of the earth rotation on the interfacial wave solutions and wave-induced tangential stress in a two-layer fluid system

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Acta Oceanologica Sinica 2009年第2期28卷 115-120页

作者： SONG Jinbao LIU Yongjun Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China key laboratory of Ocean Circulation and Waves （KLOCAW） Chinese Academy of Sciences Qingdao 266071 China Graduate University of chinese academy of sciences Beijing 100039 China

Interfacial waves and wave-induced tangential stress are studied for geostrophic small amplitude waves of two-layer fluid with a top free surface and a fiat bottom. The solutions were deduced from the general form of linear fluid dynamic equations of two-layer fluid under the f-plane approximation, and wave-induced tangential stress were estimated based on the solutions obtained. As expected, the solutions derived from the present work include as special cases those obtained by Sun et al. （2004. Science in China, Ser. D, 47（12）： 1147-1154） for geostrophic small amplitude surface wave solutions and wave-induced tangential stress if the density of the upper layer is much smaller than that of the lower layer. The results show that the interface and the surface will oscillate synchronously, and the influence of the earth＇s rotation both on the surface wave solutions and the interfacial wave solutions should be considered.

关键词： two-layer fluid interfacial waves wave-induced tangential stress earth rotation

Differential Hydrological Grey Model (DHGM) with self-memory function and its application to flood forecasting

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Science China(Technological sciences) 2009年第4期52卷 1039-1049页

作者： CHEN XiangDong1, XIA Jun1,2 & XU Qian3.1 key laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic sciences and Natural Resources Research,{3., Beijing 100101, China 2 State key laboratory of Water Resources and Hydropower Engineering Science, wuhan University, wuhan 43.072, China 3.School of Hydrology and Water Resources, Hohai University, Nanjing 210098, China key laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China State key laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan China School of Hydrology and Water Resources Hohai University Nanjing China

This paper addresses a problem of flood forecasting with the self-memory function. Considering flood forecasting’s uncertainty and updating demand, a hybrid hydrological model, namely Differential Hy- drological Grey Model with self-memory function (DHGM-SM), is developed. The model has two fold features. One is to establish a self-memorization equation linked with DHGM, that could extract useful information from past data series and realize updating of hydrological dynamic process. The other is that this model has higher efficiency relative to original hydrological model without self-memory func- tion. This approach was applied to river flow forecasting of two representative basins in Tunxi of South China and Daqinggou of North China. It is shown that this hybrid method has satisfactory forecasting accuracy by examination of both calibration and validation.

关键词： differential grey model the self-memorization principle real-time forecasting faded-memory recursive least square method