Chongqing, China
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Wang X.,Chongqing Survey Institute | Zuo W.,Henan Polytechnic University | Zhou C.,Chongqing Survey Institute | Chen Y.,Chongqing Survey Institute | Hou Y.,Chongqing Survey Institute
Modern Tunnelling Technology | Year: 2017

Considering that accuracy in measuring and predicting the rock deformation featured by time-varying increase and randomness is a key measure for ensuring the safety of tunnel construction, this paper predicts the rock deformations under three models, i.e., a conventional GM (1, 1) model, a homogeneous exponential function GM (1, 1) model and a non-homogeneous exponential function GM (1, 1) model, and makes a relevant comparison. The results show that: the errors under the three models are 7.16%, 5.01% and 2.99%, respectively, while the relative errors are -8%, -5.52% and -3.05%, respectively, indicating that the non-homogeneous exponential function GM (1, 1) model is highly accurate for deformation prediction. © 2017, Editorial Office of "Modern Tunnelling Technology". All right reserved.

Wang J.,East China Institute of Technology | Wang J.,Chongqing Survey Institute | Chen H.,Wuhan University
Applied Mechanics and Materials | Year: 2012

Spherical cap harmonic (SCH) theory has been widely used to format regional model of fields that can be expressed as the gradient of a scalar potential. The functions of this method consist of trigonometric functions and associated Legendre functions with integral-order but non-integral degree. Evidently, the constructing and computing of Legendre functions are the core content of the spherical cap functions. In this paper,the approximated calculation method of the normalized association Legendre functions with non-integral degree is introduced and an analysis of the entire order of associated non-Legendre function calculation is presented. Besides, we use the Muller method to search out for all intrinsic values. The results showed that the highest order of spherical harmonic function for constructing regional model of fields is limited, thus high-resolution spherical harmonic structure of local gravity field need to be improved. © (2012) Trans Tech Publications, Switzerland.

Ren S.,Chongqing University | Ren S.,Chongqing Survey Institute | Li X.-Y.,Chongqing University | Jiang D.-Y.,Chongqing University | And 3 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

Based on the features of Chinese salt rock bed, the comprehensive evaluation system of the stability of rock salt gas storage with multilevel and multi-index has been set up; and the assessment class level of the stability of rock salt gas storage during the operation period also has been defined. According to the test data and the result of numerical simulating, the scoring models of evaluation indices are built and the value of the corresponding evaluation indices for every assessment class is got. The weight of the describing layer and the index layer has been obtained by analytic hierarchy process. Both the extension evaluation and the fuzzy comprehensive evaluation have been used to evaluate the stability of Jintan Xi-1 salt rock gas storage of the West-to-East Natural Gas Transmission Project. And the results of the two above methods are consistent, just like the real situation, which show that it is of great worth to set up the comprehensive evaluation system of the stability of rock salt gas storage with multilevel and multi-index.

Chen J.,Fujian Provincial Geomatics Center | Hu B.,Chongqing Survey Institute | Zuo X.,Kunming University of Science and Technology | Yue Y.,Shenzhen University
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2014

Understanding personal profiles like preferences, income levels, and geographical areas is the basis of providing a person with personalized and accurate services. In order to acquire personal profiles we propose a reasonable technical route that first extracts the geographic regions from personal mobile phone location data based on a density-based clustering algorithm. Then, the geographic regions are tagged with semantic meaning and we analyze house descriptions by NLP(Natural Language Processing). A division method for people's daily time is given, based on the assumed the activity patterns of people. At last, an individual's taste for something or his income levels is analyzed using the statistics for POIs and house prices in the extracted places. An experiment with real data shows that this method is an effective solution to mining personal profiles.

Xu Z.,Wuhan University | Xu Z.,Chongqing Survey Institute | Xu Z.,Chongqing Cybercity Science and Technology Co. | Li L.,Wuhan University | And 2 more authors.
Survey Review | Year: 2016

Mobile mapping systems (MMSs) provide capability for direct geo-referencing, and rapid and convenient acquisition of geographic data elements. Combining global positioning system/inertial measurement unit/distance measurement indicator (GPS/IMU/DMI) data is one of the most attractive methodologies for such systems. Inertial measurement unit data give attitude information, but the equipment is expensive and faces technological blockade by foreign companies. To overcome this limitation, the current paper explores a soft-IMU technique based on panorama vision, which can acquire more information from the environment because of its wide instantaneous field of view (IFOV) compared with traditional cameras. The proposed soft-IMU technology automatically extracts and tracks image registration points (IRPs) in panorama data, and corrects paths using correction points. The development history of the mobile mapping system, the software and hardware configuration of our prototype digital panorama mapping DPM™ products, the system calibration model principle and object measurement are described. Finally, it is demonstrated that the system precision meets the demands of daily data acquisition in field experimental studies. © 2016 Survey Review Ltd.

Tang W.,Wuhan University | Xu K.,Wuhan University | Jin L.,Wuhan University | Wen X.,Chongqing Survey Institute
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2015

This paper first discussed the mathematical model of BeiDou/GPS combined pseudo-range point positioning. And then observational data of Beijing and Wuhan stations was used to compare BeiDou/GPS combined solution results with BeiDou and GPS single system solution results on the aspects of satellite visibility, PDOP value, positioning accuracy and usability in multiple simulative masking environment. The numerical results showed that compared with the pseudo-range point positioning of a single system, BeiDou/GPS combined positioning greatly increases the number of visible satellites and reduces the PDOP value. In addition, the combined system can effectively improve the positioning accuracy and the usability under poor observation conditions. ©, 2015, Wuhan University. All right reserved.

Tang F.,Chongqing University | Tang F.,Chongqing Survey Institute | Xiang Z.,Chongqing Survey Institute | Teng D.,Chongqing Survey Institute | And 2 more authors.
International Conference on Digital Signal Processing, DSP | Year: 2015

In this study, a multilevel change detection method is proposed for buildings using airborne laser scanning point cloud data and GIS vector data. To detect detailed information of each changed building, the roof points and corresponding roof segments in laser scanning data are obtained by a multi-entity based classification method and a connected component analysis with defined rules based on prior knowledge. Then the alpha-shapes algorithm is performed to detect the edges of the roof. Finally, the proposed change detection method is used to detect changes between buildings in laser scanning data and GIS data. Experiment results suggest that both qualitative and quantitative analysis of changes can be obtained by this method, and the overall correctness of change detection achieves to 95%. Moreover, compared with most change detection methods which detect changes as demolished or newly built building, the method in this article can detect much more specific changes, the changed edges, for partly changed buildings. © 2015 IEEE.

Ye C.,Chongqing University | Li X.,Chongqing survey institute
Journal of Computers | Year: 2010

We have proposed an Attribute-Based Delegation Model (ABDM), in which delegatee must satisfy both delegation prerequisite condition (CR) and delegation attribute expression (DAE) when assigned to a delegation role. ABDM introduce some auto revocation mechanics to support two new types of auto revocation: revocation triggered by the change of user's delegation attribute expression and revocation triggered by the change of delegated permission's delegation attribute expression, which are different from existing revocations. ABDM supports auto revocation triggered by time. This paper also discusses system cost of auto revocation and security of multi-step delegation. An auto revocation algorithm and a system architecture are proposed in the end of this paper. © 2010 ACADEMY PUBLISHER.

Zhou C.,Chongqing Survey Institute | Chen J.,Chongqing Jiaotong University
Chongqing Daxue Xuebao/Journal of Chongqing University | Year: 2012

In process of the tunnel construction throw New Austrian Tunnelling Method, the result of smoothwall blasting to rock tunnel is not good, there are more and more cavities produced behind the lining. On the basis of engineering project, this paper makes the three-dimensional elastic-plastic analysis throw numerical simulation, discusses the stress-strain behavior of primary support when there is a different size of rectangle cavity behind the lining. In addition the safety factor of tunnel is calculated with cavity based on the strength reduction finit element method. This factor is compared with the factor of health tunnel. The stability of tunnel structure system is estimated through the linear regression analysis between stress of lining and safety factor.

Chen Y.,Chongqing Survey Institute | Duan H.,Chongqing Survey Institute | Zhou C.,Chongqing Survey Institute
Applied Mechanics and Materials | Year: 2013

The slope deformation and instability caused by rainfall is the most common geological hazard in the highway slope landslide hazards. This paper used the finite element method to analyze the stability of slop in a variety of water-saturated conditions based on the strength reduction method, and to get the mechanism of rainfall weakening the strength of landslide. The results shows that the slope landslide in the fully saturated state would be instability when the surface was muddy geotechnical (thickness about 5 m), but it could remain stable when the saturated rate was under 80%. Under the action of rainfall, the maximum shear stress of potential slip plane in this kind of slopes was in the landslide's lower edge which has obvious stress concentraten. Therefore, slope control measures should be strengthened to prevent the occurrence of the landslide hazard in the lot of long rainy season. © (2013) Trans Tech Publications, Switzerland.

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