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71.
ZHANGQiaoping IsabelleCouloigner 《地球空间信息科学学报》2004,7(2):89-95
This paper presents a tramework for road network change detectlon In order to upctate the Canadian National Topographic DataBase (NTDB). The methodology has been developed on the basis of road extraction from IRS-pan images (with a 5.8 m spatial resolution) by using a wavelet approach. The feature matching and conflation techniques are used to road change detection and updating. Elementary experiments have showed that the proposed framework could be used for developing an operational road database updating system. 相似文献
72.
On the basis of previous work, this paper designs an intelligent agent based on virtual geographic environment (VGE) system that is characterized by huge data, rapid computation, multi-user, multi-thread and intelligence and issues challenges to traditional GIS models and algorithms. The new advances in software and hardware technology lay a reliable basis for system design, development and application. 相似文献
73.
Implementation of OGC web map service based on web service 总被引:7,自引:0,他引:7
JIAWenjue CHENYumin GONGJianya 《地球空间信息科学学报》2004,7(2):148-152
OGC Web Map Service is one kind of OGC Portrayal Services belongs to OGC Web Service model and it provides multi-platform interoperability of spatial data set. This paper presents a method for implementing OGC Web Map Service based on Web Service technique and introduces the detailed process. 相似文献
74.
PANJianping YEHuanzhou 《地球空间信息科学学报》2004,7(2):153-156
A few researches adopt virtual reality in landslide. So it is significant to combine the physicsbased deformable method with the process simulation of a sliding landslide, this way the dynamic process of a going landslide can be simulated. The analysis of the dynamic law of landslide provides a foundation to forecast and make it realiable to foretell disasters. After recounting the condition of VR and landsliding body simulation, this paper puts forward simulating landslide by the physics-based deformable method. The method divides landsliding into deformable body and rigid one. The deformation of deformable body can be compute by DDA and FEM, and DDA fits the great deformation and FEM is good for the tiny deformation. This paper shows it is feasible to simulate the landslide animation by this method. 相似文献
75.
DUANSujuan HONGFan LIXinhua 《地球空间信息科学学报》2004,7(4):303-307
To meet the authorization administration requirements in a distributed computer network environment, this paper extends the role-based access control model with multiple application dimensions and establishes a new access control model ED-RBAC(Extended Role Based Access Control Model) for the distributed environment. We propose an extendable hierarchical authorization assignment framework and design effective role-registering, role-applying and role-assigning protocol with symmetric and asymmetric cryptographic systems. The model can be used to simplify authorization administration in a distributed environment with multiple applications. 相似文献
76.
The present paper focuses on land cover dynamics pattern in Balkhila sub-watershed situated in Garhwal Himalayas. This study
contributes example from human shaped ecosystem in mountainous regions where fragmentation of natural resources is active.
The remote sensing and GIS has been used to understand the land cover dynamics along the topography. The results report that
the land cover dynamics is dependent on the aspect due to sun illumination. The altitude and slope are no more a barrier for
resource extraction and the human activity zone is shifting towards higher altitudes and slopes. The changes are also defined
along the road and settlements. 相似文献
77.
R. Ramakrishnan S. Manthira Moorthi N. Padmanabhan P. Gupta 《Journal of the Indian Society of Remote Sensing》2004,32(1):103-111
Panchromatic data of pixel resolution 5.8 m obtained from IRS-1C and IRS-1D satellites proved to be very useful for mapping
purposes. One of the popular data product is the 70 km swath mosaic which is covered by a combination of 3 CCD line sensors,
each with 4096 pixels. Each CCD-line sensor with different imaging times causes geometric problems of mosaicing three strips
data together. In this paper, we propose the details of the design elements of system that caters to the need for accurate
and automatic multi strip image registration without any second resampling of the data. The systematic geometric correction
grid mapping is improved to facilitate accurate mosaicing by automatic image registration task that makes use of the overlap
data within image strips and image registration is achieved up to sub-pixel level. 相似文献
78.
79.
Doug Hunt 《GPS Solutions》2000,4(1):74-76
The GPS Toolbox is dedicated to highlighting algorithms utilized by GPS engineers and scientists. If you have an interesting
algorithm you would like to share with our readers or if you have a topic you would like to see covered in a future column,
contact us at gps-toolbox@ngs.noaa.gov. To comment on the algorithms presented here, or to leave a request for an algorithm
you may be looking for, visit our Web site (http://www.ngs.noaa.gov/gps-toolbox). ? 2000 John Wiley & Sons, Inc. 相似文献
80.
In this paper, we describe the computational framework of a novel method for solving the challenging problem of probabilistic
finite elements. The method is called Improved Dynamic Bounds (IDB) and was developed recently to improve the efficiency of
the dynamic bounds. The IDB is used in finite element numerical models to calculate time-dependent failure analyses of structures.
In applications, the IDB can speed up the overall simulation process by several orders of magnitude. In applications controlled
by two influential variables (e.g, two-dimensional problem), the computational efficiency is improved by a factor of 769 according
to Rajabalinejad (2009). Applications of IDB indicate the method is most efficient for problems where the number of influential variables are limited.
This is often the case for geotechnical and coastal flood defence systems. The IDB method is applied in this paper to the
17th Street Flood Wall, a component of the flood defence system (levee infra-structure) that failed during the Hurricane Katrina,
to calculate the failure probability of an I-wall. 相似文献