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Chongqing, China

Ren S.,Chongqing University | Bai Y.-M.,Chongqing University | Jiang D.-Y.,Chongqing University | Li X.-Y.,Chongqing University | Wang X.-S.,Chongqing Survey Institute
Mechanical Behavior of Salt VII - Proceedings of the 7th Conference on the Mechanical Behavior of Salt | Year: 2012

Chinese salt rock bed contains many interlayers. The amount and the mechanical properties of the interlayer have serious effect on the stability of salt rock gas storage. So the stability model of salt rock gas storage with multi-level and multi-index during the operation period has been set up. And the assessment class level of the stability has been defined. According to the test data and the result of numerical simulating, the scoring models of the evaluation index are built. The weight of the describe layer and the index layer has been obtained by analytic hierarchy process. The extension evaluation method has been used to evaluate the stability of Jintan Xi-1 salt rock gas storage of West-to-East natural gas transmission project with the stability model. And the result is in accordance with the real situation, which shows that the stability model of salt rock gas storage with multi-level and multi-index during the operation period is worth popularizing. Source

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. Source

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. Source

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. Source

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. Source

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