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IONOSPHERIC EFFECTS ON GPS NAVIGATION IN LOW-LATITUDE AREA

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IONOSPHERIC EFFECTS ON GPS NAVIGATION IN LOW-LATITUDE AREA

第一届交通运输工程国际学术会议

作者： GAO Shan1, 2.and CHEN Wu2.1school of Civil engineering, Southwest Jiaotong {2., Chengdu, Sichuan, china, 610031 2.ept. of Land surveying and geo-Informatics, The Hong Kong Polytechnic {2., Hong Kong

Ionospheric effects are the major constraints for GPS navigation. Especially, at low latitude, ionospheric delay varies greatly both in space and time. Even for short baselines, ionospheric effects cannot be cancelled out with double difference algorithm. Strong ionospheric disturbances are also observed in the region. In this paper, ionospheric behavior in Hong Kong is investigated by using a dense reference network. The effects of ionospheric disturbances on GPS receiver, such as loss of lock, gross error and measurement noise are studied.

关键词： GPS navigation ionospheric delay loss of lock cycle slip

Study on Design of Protective Coal Pillar for High Buildings

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Study on Design of Protective Coal Pillar for High Buildings

2.10(沈阳)国际安全科学与技术学术研讨会

作者： CHAI Hua-bin~(1,2. (1.State Bureau of surveying and Mapping Key Laboratory of Mine Spatial Information Technologies,Henan Polytechnic university,Jiaozuo Henan 454003,{2. 2.school of surveying and Land Information engineering,Henan Polytechnic university,Jiaozuo 454003,{2.)

＜正＞Considering the fact that the protective coal pillar is affected by the point load of high buildings,the calculating formula of the critical load and actual load of the protective coal pillar were worked *** the stability of the protective coal pillar under the load of the high buildings on the ground was analyzed by the *** to the geometric and physical natures of the major influence radius,which is one of the predicting parameters of surface displacement and distortion,a simple and useful method of designing protective coal pillar for high buildings were *** shows that the mining rate and the stability of the protective coal pillar can be improved,at the same time the ground high buildings can be protected from the mining damage by adopting the method.

关键词： high building protective coal pillar major influence radius stability

A comparison of two ISRM suggested chevron notched specimens for testing mode-Ⅰ rock fracture toughness

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A comparison of two ISRM suggested chevron notched specimens...

中国科学院地质与地球物理研究所第十届(2.10年度)学术年会

作者： Zhen-dong Cui~(a,*),Da-an Liu~a,Guang-ming An~b,Bo Sun~a,Miao Zhou~c,Fu-quan Cao~c a Key Laboratory of geo-mechanics,Institute of geology and geophysics,Chinese Academy of Sciences,beijing 10002.,china b CNNC china Nuclear Power engineering Co.,Ltd,beijing 100840,china c china university of mining and technology,school of Mechanics and Civil engineering,beijing 100083,china

*** Along with the rapid development of human engineering activities,more and more rock engineering,such as drilling, excavation,explosion and cutting of rocks,calls for application of the principles,methods and techniques of rock fracture mechanics. Rock fracture toughness is a key parameter in rock fracture mechanics used to forecast the rock crack initiation and

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Stability analysis of soft foundation earth-rock dam in lake

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Stability analysis of soft foundation earth-rock dam in lake

The 2.d ISRM International Young Scholars’Symposium on Rock Mechanics

作者： B.H.Zhu & Z.Y.Tan State Key Laboratory of High-efficient mining and Safety of Metal Mine,university of Science and {2. beijing,Ministry of Education,beijing,china school of Civil and Environment engineering,university of Science and {2. beijing,beijing,china

Based on the engineering and hydrological geological condition in Chengmen Lake,the properties of earth-rock compound and silt at the lake bottom are analyzed and geo-mechanical model of the sof t foundation earth-rock dam is *** stability of the dam under the impact of fluctuating lake waters and lakebed silt extrusion is simulated with *** stability and safety of the dam are assessed under the criteria of displacement mutation as well as *** results reveal the deformation and displacement law of the dam under various actions of external conditions,which provide certain theoretical guide to treatment and maintenance of the dam.

关键词： Stability analysis of soft foundation earth-rock dam in lake

Stochastic Model of GPS/BD Combined Standard Single Point Positioning

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Stochastic Model of GPS/BD Combined Standard Single Point Po...

第三届中国卫星导航学术年会

作者： Wenkun Yu 1,Wujiao Dai 1,Xiaoli Ding 2.Wentao Yang 2.Xiao Gao 1 1 school of geosciences and Info-physics {2.,Central South university,Changsha,Hunan,china 2.Department of Land surveying and geo-Informatics,The Hong Kong Polytechnic university,Hung Hom,Kow Loon,Hong Kong

Reasonable determination of weights is the key factor in giving full play to advantages of GPS/BD combined ***,Helmert VCE （Variance Component Estimation） is employed aiming at adjusting the variance-ratio between the two heteroscedastic ***,the precise priori weight matrix can enhance the convergence of iteration methods based on posteriori information,reduce the iteration’s ***,system related errors,together with outliers,influence the estimation,leading to a distorted stochastic ***,in this paper,based on robust Helmert VCE and using integrated priori accuracy,taking various error sources into consideration,an initial weighing method for combined system is suggested.

关键词： GPS/BD robust Helmert stochastic model

Temporal and Spatial Variability of Dissolved Organic Carbon Concentration in the Xijiang River, South china

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Journal of Mountain Science 2011年第5期8卷 694-703页

作者： TAO Zhen GAO Quanzhou GUO Wenping WANG Zhengang ZHANG Yongling XIE Chenji HUANG Xiakun ZHONG Hongwei school of geography and Planning and Guangdong Key Laboratory for Urbanization and Geo-simulation Sun Yat-sen University Guangzhou 510275 China Wuzhou Branch Guangxi Regional Hydrological and Water Resources Bureau Wuzhou 543002 China Makou Hydrological Gauge Station Guangdong Province Hydrological Bureau Foshan 528100 China

A whole year analysis of riverine dissolved organic carbon (DOC) concentrations in the Xijiang River (XJR), South china, showed that the mean riverine DOC concentration (1.2. mg L-1) in the XJR was notably lower than the averaged value (5.75 mg L-1) of the global riverine DOC concentration in several major rivers. There is an inconspicuous monthly fluctuation of the DOC signal in the XJR, but on a semi-yearly time scale, however, the riverine DOC concentration had significant difference between hydrological seasons. The DOC level during the flood season (1.18 mg L-1) was less than that during the non-flood season (1.40 mg L-1). Owing to the concomitance of the flushing and dilution effects of the runoff during the high-water period, the variation of riverine DOC concentration with discharge in the XJR differed from that reported in many other major rivers. The DOC export flux above the city of Wuzhou was about 0.62. 106 g C km-2.yr-1. The DOC transported during the "056" Massive Flood period comprised 30.35% of the annual total, while the discharge accounted for 36.32. of the total annual flow. The characteristics in riverine DOC concentration in the XJR were attributed to the combined effect of the geomorphologic, monsoon climatic and hydrological processes as well as land-use within the drainage basin.

关键词： Export flux Hydrological processes Massive flood Riverine dissolved organic carbon The Xijiang River

Direct Creation of Construction Drawings for Kwan-yin Statue by Close-Range Photogrammetry

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geo-Spatial Information Science 2002年第3期5卷 58-64页

作者： FENG Wenhao LI Xin JIANG Wanshou GAO Xinqiaoprofessor,Ph.D supervisor,school of Remote Sensing and Information engineering,Wuhan {2.,12. Luoyu Road,Wuhan 430079,china. school of Remote Sensing and Information engineering Wuhan University

In order to provide the model point accuracy of ±2.mm,an extra high accuracy industrial control net with four surveying piers with accuracy ±0.1 mm was set up around the *** of orientation marks have been placed on the different parts and measured with accuracy ±0.2.mm from the above_mentioned *** main four stereopairs taken with the P31 camera around the model are simultaneously processed on the BC2.analytical *** accuracy of absolute orientation is better than ±0.9 ***,about 300 sections construction drawings have been directly offered,and the close_range photogrammetric data has been used for the design and construction of the statue.

关键词： closerange photogrammetry Kwanyin Statue construction drawing industrial control net high accuracy

Early Warning System for Enterprise Supply Chain Crisis Based on Back-Propagation Neural Networks

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Early Warning System for Enterprise Supply Chain Crisis Base...

The Third International Conference on Information Systems for Crisis Response and Management & the Fourth International Symposium on geo-Infprmation for Disaster Management

作者： Rong Du school of Economics and Management Harbin engineering {2. Harbin china 150001 Ye Sun school of Economics and Management Harbin engineering {2. Harbin china 150001

＜正＞The structure of enterprise supply chain is very complicated,and the whole supply chain might be out of control because of a tiny problem occurred in any ring of the *** order to predict the supply chain crisis effectively, based on back-propagation neural networks（BPNN）,this paper estabhshed an early warning system model for supply chain crisis,elaborated the system’s structure,analyzed the early warning system’s operational mechanism, and estabhshed an index system.A case study was offered to prove the feasibility and effectiveness of this early warning system.

关键词： Supply chain crisis early warning system knowledge mining BPNN

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泰安岩溶水系统地下水水量水质模拟与预测

济南大学学报（自然科学版） 2003年第4期17卷 301-304页

作者：马振民裴现勇邢立亭济南大学城市发展学院济南大学土建学院山东济南250022 山东省地矿工程勘察院山东济南250013

运用建立的地下水水量水质耦合模型 ,以 2.0 0 0年为基准 ,对泰安岩溶水系统 2.0 10年的水量及水质进行了模拟预测 ,指出现状开采条件下岩溶水系统地下水环境将持续恶化 ;为了实现地下水资源可持续利用。

关键词：岩溶水系统地下水水量水质耦合模型模拟预测