37868959
A Method of Raster Data Mining Based on Multi Dimension Data Set
Spatial Data Mining can mine automatically or semi-automatically unknown, creditable, effective, integrative or schematic knowledge which can be understood from the increasingly complex spatial database and enhance the ability of interpreting data to generate useful knowledge. There are large amounts of data existing in the database of Government GIS. However, a great deal of the data is idle, which has caused a huge waste of data due to rarely effectively utilization in practice. It is very necessary to deal with the task of data mining based on Government GIS. In this paper, an example on land utilization and land cover in a certain region of Guizhou Province was presented to describe the course of spatial data mining. There into, a derived star-type model was used to organize the raster data to form multi dimension data set. Under these conditions, clustering method was utilized to carry out data mining aiming at the raster data. Based on corresponding analyses, users can find out which types of vegetation were suitable for being cultivated in this region by using related knowledge in a macroscopic view. Therefore, feasible service information could be provided to promote economic development in the region.
37887576
Design and Application of GIS Software Platform Integrating with DSS Oriented to E-Government
Both Geographic Information System (GIS) and decision support system (DSS) are playing an important part in government affairs management or electronic government (E-government). But GIS and DSS are usually independently working the interactive relation between them is unsubstantial, so that application of E-government to GIS is inconvenient and inefficient. This paper puts forward a new idea for designing software platform based on integrative GIS and DSS according to target of E-government construction in China, introduces the function integration target, method and technical way in different levels of this platform. This paper has found a new way of GIS development oriented to E-government, and described successful application in a series of G-government project, such as General National Situation Information System, Flood and Drought Prevention Information Service System, West Development Information Service System and so on.
39558628
Combined adaptive beamforming with space-time block coding for multi-antenna communications
Aiming at the multi-antenna communication systems, a downlink transmit scheme combining adaptive beamforming (ABF) with space-time block coding (STBC) is first presented, which utilizes the maximization of the output mean signal-to-noise ratio (SNR) and the minimization of the symbol error rate (SER) upper bound of the three widely used modulations as the design criteria. Then, based on the moment generating function (MGF) and the Gauss-Chebyshev integration, a simple and accurate numerical method is presented to analyze the SER performance of the system with the new transmit scheme under the three commonly used modulations. Finally, computer simulation results demonstrate the effectiveness and superiority of the proposed strategy.
1210599
Joint error concealment and error recovery for consecutive frame losses under the unbalanced multiple description coding architecture
Real-time video transmission over error-prone wireless networks often experiences consecutive frame losses due to either temporary link outages or traffic congestion. Although error concealment (EC) techniques have been extensively studied, they usually cannot handle the problem. Thus, we envision using EC under the unbalanced multiple description coding (UMDC) architecture. UMDC has almost no coding delay and can produce two descriptions at any bit-rates adaptive to different path bandwidths. In this paper, we propose an iterative EC algorithm able to adaptively exploit both the high-resolution (HR) and low-resolution (LR) information via multi-hypothesis weights. It is applied to both lost HR frames and following undecoded ones. Considering error propagation, we design an interframe error recovery (ER) algorithm for the undecoded HR frames. It iteratively uses multi-frame recovery principle to frame-by-frame reduce error drift in the HR stream with respect to the intermediate information from EC. The joint design of EC and ER can be applied to most UMD approaches. Extensive experiments have been carried out under different conditions. The proposed EC technique exhibits high PSNR gains versus the usual ones under the UMDC architecture and the classical ones without the support of UMDC. The proposed ER technique is efficient in reducing error drift. In conclusion, joint EC and ER can provide satisfactory performance on both PSNR and visual quality.
10918777
Online Signature Verification by Combining Shape Contexts and Local Features
Most parameter-based online signature verification methods achieve correspondence between the points of two signatures by minimizing the accumulation of their local feature distances. The matching based on minimizing the local feature distances alone is not adequate since the point contains not only local features but the distribution of the remaining points relative to it. One useful way to get correspondences between points on two shapes and measure the similarity of the two shapes is to use the shape context, since this descriptor can be used to describe the distributive relationship between a reference point and the remaining points on a shape. In this paper, we introduce a shape context descriptor for describing an online signature point which contains both 2D spatial information and a time stamp. A common algorithm, dynamic time warp (DTW), is used for the elastic matching between two signatures. When combining shape contexts and local features, we achieve better results than when using only the local features. We evaluate the proposed method on a signature database from the First International Signature Verification Competition (SVC2004). Experimental results demonstrate that the shape context is a good feature and has available complementarity for describing the signature point. The best result by combining the shape contexts and the local features yields an Equal Error Rate (EER) of 6.77% for five references.
26519336
Iris Recognition Algorithm Using Modified Log-Gabor Filters
In this paper, we presented an iris recognition algorithm based on modified Log-Gabor filters. The algorithm is similar as the method proposed by Daugman in general procedure while modified Log-Gabor filters are adopted to extract the iris phase information instead of complex Gabor filters used in Daugman's method. The advantage of Log-Gabor filters over complex Gabor filters is the former are strictly bandpass filters and the latter are not. The property of strictly bandpass makes the Log-Gabor filters more suitable to extract the iris phase features regardless of the background brightness. The comparison experiments between complex Gabor filters based methods and the proposed method are also presented in this paper
27275974
Distributed Spatial Catalog Service on the CORBA Object Bus
Spatial catalog service is a necessary component for distributed geographic information. Spatial catalog services provide the capabilities for organizing and managing spatial metadata. Catalog services simplify the process of data discovery in a large spatial database, facilitate data transfer, and help data fusion.This paper presents a software architecture for spatial catalog services. We first discuss the general concept of spatial catalog facilities and the logical model of spatial catalog services. We then introduce the distributed object-oriented model for spatial catalog services based on the industrial standard Common Object Request Broker Architecture (CORBA). The core components of spatial catalog services, catalog and catalog registry, are described in detail with the CORBA Interface Definition Language (IDL). Examples are given to illustrate the structure of the catalog component and its relations with other service components in a distributed GIS. The model provides a common interface to spatial catalogs and related data no matter how catalogs are defined, what formats they use, and where they are located. It provides crucial services in a distributed Geographic Information System.