Applied Mechanics and Materials Vols. 256-259

Abstract: A necessary updating degree is vital for the digital map data in a vehicle navigation system. Only when the digital map data are well updated, can the quality of the navigation be assured. Today the companies devoting to the production of digital map data for vehicle navigation have to cost much labor, material and capital to collect and update data in order to maintain a necessary updating degree. Throughout the history of electronic navigation data updating, they have made considerable progress both on the methods and processes of data production, and the way of map management. Updating from the CD to the network, from the wired to the wireless, from the replacing to the incremental way, each of the technical changes is a power source to enhance the data updating rate. As we all know, the change detection is a prerequisite and base for the electronic navigation data updating. By rapidly developing the area with changes and using the appropriate updating method, we can scientifically maintain the original database of navigation data and terminal physical data. In view of this, starting from application needs for dynamic data updating, this paper analyses change detection methods of navigation data in different versions used for generating incremental data, and focuses on that of rasterizing features and attributes, exploring a new approach to quickly get the incremental data between versions.

Abstract: 3D geological modeling is an inter-discipline subject applying computer technology to the geological research. With the development of Internet, 3D geological modeling based on Web has become a hot spot. In this article, we applied the Flash3D technology to the 3D geological modeling based on Web. We designed a process which use borehole data as original data source, automatic interpolation and identify strata from it, then calculate modeling data. We developed a 3D geological and geographical system based on Flex and Java platform using Flash3D engine technology. The system is a true 3D geological modeling software in B/S mode.

Abstract: In this paper, based on high resolution remote sensing image and the corresponding civil areas of digital topographic map, by using modules and effective classification method of ENVI software and ARCGIS software, by calculating the shadow of one building to obtain the height of it in city. Practice has proved that this method brings small workload, owns simple process, and can basically meet the needs of a city’s reference requirements of relevant disaster preventions and mitigations planning. It has practical value.

Abstract: The paper chooses Genhe, Inner Mongolia as the research area. Based on ArcGIS 9.2 and ENVI 4.8 software, the TM images of 2000、2004 and 2010, the decision tree classification was applied to interpret the images, and the land use data of 2000、2004 and 2010 were obtained. The land use transformation matrix and land use dynamic degree were analyzed further. Results are shown as follows. (1) Decision tree classification can be used in the study area and classification accuracy is high. (2) Land use change underwent a process of obvious change from 2000 to 2010. The areas of forest and residential land underwent substantial increase, while the areas of sparse forest and grassland got a huge decrease.

Abstract: Spectrum sensing is the most important issue in cognitive radio (CR) that increases spectrum utilization. Therefore, an accurate, reliable and real-time method to detect the unused spectrums and available bands is required necessarily. Several methods have been introduced for spectrum sensing, which the MultiTaper nonparametric estimation Method (MTM) is the most appealing. This method is not only an efficient technique for spectrum sensing in CR systems, but also is nearly optimal for wideband signals, providing a close approximation to the maximum likelihood (ML) estimation. In this paper, we propose using MTM efficient method to Cognitive Wireless Sensor Networks (C-WSNs), and compare our results with the case of using the periodgram for spectrum sensing.

Abstract: It is cloudy and rainy perennially in many regions of China, and optical images are extremely difficult to be obtained. Synthetic aperture radar (SAR) is as a new way to provide mapping data in such areas because of the advantage of all-weather and all-time. Digital Orthophoto Map(DOM) can be generated using Airborne SAR images that has become an important means in mapping difficult areas. In this paper, DOM production process is given based on airborne InSAR data, the factors that affect airborne SAR DOM accuracy are analysed, and the quality evaluation criteria of airborne SAR DOM is introduced. There are some main technical problems such as shadow, layover, Edge Snap and cutting alignment in the DOM production process, and the solution of the problems is presented in this paper.

Abstract: Using the 1987 TM and 2006 ETM+ remote sensing images and other related ancillary geographical data of Huainan city, combined with GIS Technology, the dynamic change of the coal mining subsidence of Huainan city was extracted. In order to unify the two period image data difference because of the different date, the research used modified normalized difference water index (MNDWI) to get the information of seeper subsidence in coal mining district. Using the change detection function of RS, Combined with the spatial analysis and statistics function of GIS, all the subsidence area of coal mining district and the seeper subsidence area were extracted. The research shows that the seeper subsidence extent is different because of the mining period, scale, method, groundwater level and groundwater extraction, surface coverage, roof’s management and other coal seam geological environments, especially dip angle of coal seam. The Xiejiaji and Bagongshan mine’s mining seeper subsidence are the serious due to its bigger dip angle of coal seam, the seeper subsidence percentage are 38.57%, 25.95% respectively, while Jiulonggang- Datong mining seeper subsidence is the least even if it’s the oldest and abandoned mine in Huainan.

Abstract: This paper makes use of the three-dimensional laser scanning technology measurement speed and high precision which combines the advantage of the field control survey, coordinate system transformation, the point cloud data processing, establish the triangle nets, texture mapping etc process, get the space of ancient cultural relics data and texture, antiquities for 3D modeling provide real, real size, real texture digital model for reference.

Abstract: Oil spills are almost constantly present in recent years, which cause ecological disaster of marine environment. It is important to detect the area of oil spill to take rescue measurement in time. The paper took the EnviSat Asar image as example to detect the boundary of oil spills. Firstly, the paper removed speckle noise by Histogram Equalization. Then, image segmentation was carried out by open-close mixed operation in mathematical morphology. At last, the region of oil spill was exacted independently.

Abstract: A new method to realize 3D measurement and modeling based on Active Control System was put forward in the paper. The Active Control System included two parts: one was for the calibration of digital camera, and the other was for the six-freedom control of digital camera. This method enlarged the intersection angle and improves the intersection precision by multi-baseline photography; enlarges the angle of view by panning photography, and resolves the difficulty of matching for images with large intersection angle. The experiments proved that this method can acquire the high accuracy and improves the production efficiency.