Junsheng Li

A dynamic Access Control model based on trust

Since Role-Based Access Control (RBAC) shows great advantage in meeting the security need in large-scale and enterprise-wide system, RBAC becomes the hot topic in access control research field. However, current approaches to access control are mostly based on individual user identity; hence they do not scale to distributed systems. So, the paper analyses RBAC could not satisfy dynamic access control in distributed environment, and puts forward an dynamic access control model based on roles and trust control, giving every trust value for each user by introducing trust management to access control, each role corresponds a certain trust vale, users and systems give values for each other after operation, trust management modesties and updates trust values, users roles will change accordingly, The experiment shows that the model is much validated, and something useful is obtained. The extended model can meet the need to manage and enforce the strong and efficient access control technology in large-scale environments. The flexility and broad application of the proposed model through the system is testified and something useful is obtained.

The Research and Design of Data Integration System for Urbanization

With the rapid development of urbanization in China and the rapid development of spatial and information technologies, the amount of valuable data captured in different systems and different structures grew and technical progress made it possible to link these different systems and different structures, the wish to exchange and share these data arose and became more and more important. But the combination of data done on different levels that we subsume under the term data integration requires resolving heterogeneities, which still poses research questions. Urban information is a kind of multi-sources data, which not only contain spatial data, but only contain non-spatial data. The variety of these data demands that the data integration system read all types of data, frame uniform standard to classify these data, establish the data relationship among them and integrate usable data resource. In search of solutions for these problems, the paper discusses data integration in the light of recent developments in GIS Open Source software resources that promise a more dynamic and automated data integration system for urbanization. The paper implements the data integration system in the environment of Visual C++ 6.0 combined of GDAL/OGR library, and something useful is concluded.

Th SIFT features matching for spherical panoramic images

Realistic panoramic image of its strong, deep, 360-degree panoramic view of the characteristics of convenience by the increasingly widespread concern for the real world to provide full 360 degree scene information, which has been widely applied in various fields. Panoramic three-dimensional measurement reconstruction needs to identify some feature matching. So the paper is focused on the research and applications of Spherical panoramic images feature points matching, introduces a SIFT feature matching method, which is applied to the automatic spherical panoramic image feature points matching.

The Applications and Summary of Three Dimensional Reconstruction Based on Stereo Vision

Objective world is a three-dimensional space world in which we are living. With a variety of observing systems in different forms and means of observation, what come from the objective world is a 2D image plane, although containing 3D object space information. Main research on stereo vision (more images) is to use imaging technology from the (multiple) images of objects in the scene to get the distance (depth) information. The paper is focused on the research, applications and summary of 3D Reconstruction based on stereo vision, we start with an review of stereo vision, and then we give an analysis of the application and direction of stereo vision. The paper is concluded lastly.

The Applications and Summary of Panoramic Modeling

Full view panorama of a 3D scene has become popular in building virtual reality system, and also has other applications in visualization. Which has view of the characteristics of convenience by the increasingly widespread concern for the real world to provide full 360 degree scene information, which has been widely applied in various fields. The paper is focused on the research, applications and summary of panoramic modeling, it gives an analysis of panoramic imaging technology and image projection, and then introduces the panoramic image acquisition, then analysis panoramic three-dimensional modeling last gives the conclusions.

Rapid Acquirement and Visualization of CityGML Documents

With the development of the Internet, the need of city 3D data is rising more and more, and the emphasis shifts from analysis to the sharing of city 3D data and information over the Internet. In Internet, we lack uniform 3D data standard and 3D data cannot be shared and exchanged availably. The city Geography Mark-Up Language (GML) was developed as the standard language for exchanging and sharing city 3D data in Internet. In this paper, we propose a set of data structures to obtain city 3D information from the GML file in order to extract useful information quickly, after analyzing CityGML files structure and parsing by the Document Object Model (DOM). The experiment shows that 3D data are extracted effectively, and visualized in Web application using Java, and the data structures defined in the paper are very validated.

A Kind of Map Coloring Algorithm Considering of Depth First Search

Map coloring problem is a hot topic in combinatorial optimization, which is one of the main tasks in discrete mathematics. It has gone through a long time for map coloring, especially with the development of computer wide applications. Map coloring theories has a long development, its applications are widely used. So, we propose a kind of map coloring algorithm based on depth-first search algorithm. the algorithm overcomes the shortcomings of the map colored areas compared to other algorithms. The experiment showed that the map coloring algorithm put forward by the paper is much valid, which could link these two types of data, and something useful is obtained.

A hybrid GPS height conversion approach considering of neural network and topographic correction

GPS heights conversion has become a hotspot in survey engineering. With the development of computer and information technology, artificial neural networks (ANN) has been used widely, which has the character of the high parallel distributed processing, associative memory abilities, self organization, self-learning and strong nonlinear mapping abilities, and the theory has proved that one ANN, having deviation and one S-type hidden layer or more plus one linear output layer, could approach any rational function, and the ANN has been used in GPS heights conversion. Topographic correction is to reflect the medium-wave characteristics of the geoid. The paper is focused on the GPS height conversion considering of ANN and topographic correction. The experiments show that the hybrid approach is much validated and something useful is obtained.

Optimization Model for GPS Height Fitting Considering of AIC

Polynomial fitting method is widely used in GPS height conversion into normal heights in survey engineering and whcih has become a hotspot. Different models used in different area of interpolation have different precisions, therefore, it is very important to optimize model before GPS height conversion in order to obtain high precision. Lots of engineering practice has proven that The conicoid model could satisfied forth degree demand, but there is no proof why the conicoid model is better. So, the paper introduce AIC to choose the better model for transforming GPS height, we separate the value of AIC into two parts, AICin and AICout, then add them up to obtain the total value, AICtotal, which could testify which model is the best model comparing with the relative information. The experiments show that the optimization model for GPS height fitting considering of AIC criterion is valid and something useful is concluded.

Notice of Retraction A Hybrid Conversion of GPS Height Approach Based on Neural Networks and EGM96 Gravity Model

How to transfer GPS heights into normal heights has become a hotspot in survey engineering. With the development of computer and information technology, artificial neural networks (ANN) has been used widely, which has the character of the high parallel distributed processing, associative memory abilities, self-organization, self-learning and strong nonlinear mapping abilities, and the theory has proved that one ANN, having deviation and one S-type hidden layer or more plus one linear output layer, could approach any rational function, and the ANN has been used in GPS heights conversion. EGM96 is a gravity model of the earth, which has high precision of long wavelength contribution, so the paper puts forward a hybrid approach for conversion of GPS height Based on neural networks and EGM96. Remove the long wavelength from GPS/leveling points, next construct a model from the leaving parts fitted by BP neural network to calculate other GPS points, and restore the long wavelength to the points. The experiments show that the hybrid approach is much validated and something useful is obtained.