Applied Mechanics and Materials Vols. 220-223

Abstract: Numerical simulations for the flows of typical transport configurations are performed by solving Navier-Stokes equation using TRIsonic Platform (TRIP). The purpose is to validate TRIP3.0 for the simulation of transport configurations. The configurations contain DLR-F6 and trapezoidal high lift configurations. For DLR-F6, the structured mesh and test data are obtained from DPW-III. The reference numerical results are obtained by CFL3D. For the high lift configurations, the structured mesh are generated with ICEM, and test data are obtained from HiLiftPW-1. For these configurations, the effects of grid density to aerodynamic characteristics are systematically studied. The numerical results are verified by comparison with experimental data and numerical results of CFL3D. Grid refinement leads to converged numerical results. It is demonstrated that grid density has little influence on friction drag, whereas significant influence on pressure drag for the DLR-F6 configurations. It has little influence on lift and momentum for the trapezoidal high lift configurations before stall, but has obvious influence near stall.

Abstract: This paper presents an improved video segmentation scheme, which consists of two stages: initial segmentation and motion estimation. In the initial segmentation, the watershed transformation followed by a region adjacency graph guided region merging process is used to partition the first video frame into spatial homogenous regions. Then the motion of changed region is estimated. Based on the highly efficient quadratic motion model, the motion estimation is undertaken using Gauss-Newton Levenberg-Marquardt method to minimize the least-square error function. Experimental results show the proposed scheme provides high performance in terms of segmentation accuracy and video compression ratio.

Abstract: The data structure is the form of quad-tree in this paper. The terrain node's LOD evaluation function is given through comprehensive considering the three factors which are the static error of the terrain block ,the screen space dynamic error and visual perception based on the premise of visual acuity. The smooth transition factor is used to eliminate the phenomenon of popping in the GPU vertex shader. The idea to join the skirts is used to eliminate cracks between terrain blocks. The experimental results show that the algorithm can reflect the terrain LOD levels through the fluctuant of terrain and the visual perception intensity so that the terrain has a better adaptability while increasing frame rates and rendering realistic.

Abstract: In order to facilitate the exchange and cooperation for the fusion research, we proposed the high-speed special network environment to achieve the design, research of the program and manage the project contracts, schedule, video conference system and data sharing. The article states the network acceleration mechanisms based-on the HS-TCP protocol and proposes a kind of data encryption based-on AES and SSL and describes the framework of the special network. Then we have verified the feasibility and security of the project by the experiment.

Abstract: The efficient implementation of Boolean operatio between STL models is a bottleneck problem to develop excellent RP data processing software, and the subdivision of the intersection is an important step of realization the Boolean operations. An algorithm is proposed in this paper. Based on the closed character of the STL model, the position relationship between the intersection lines and the triangle are classified, and the subdivision rules is summarized. The two data linked list of the intersection points and vertex points are created, a searching process to obtain the subdivision polygon is described.

Abstract: Floods have become increasingly alarming worldwide. In this paper, we firstly introduce the Improved BP Neural Network model (IBPNNM) based on entropy value theory in detail. Then we adopt Levenberg-Marquardt (LM) algorithm to achieve a higher speed and a lower error rate to overcome the shortcomings of the traditional BP algorithm as being slow to converge and easy to reach extreme minimum value. To illustrate the procedure of the proposed method, we apply IBPNNM to describe the flood disaster risk quantitatively in China by using statistical data respectively, including number of deaths, number of victims, collapse of housing, affected crop area, direct economic loss of 22 Areas in China in 1998. The results of IBPNNM are compared with the results of the matter-element analysis method to confirm that the proposed model is reasonable, effective and feasible.

Abstract: Packing problem is how to arrange the components in available spaces to make the layout compact. This paper adopts a digital modeling algorithm to establish a novel rubber band convex hull model to solve this problem. A ray scanning method analogy QuickHull algorithm is presented to get extreme points of rubber band convex hull. A plural vector expression approach is adopted to movement resolution,which calculate the resultant vector to translate, rotate and slide the subbody to make the volume decrease. An experiment proved this digital modeling algorithm effective.

Abstract: The reasons influencing the VoIP QoS include transmission delay, jitter and data packet drop. The main measures improving the VoIP QoS are the integrated services and the differentiated services. But the integrated service is only suitable for the small-scale network, and the differentiated services can’t guarantee QoS from the source end to the destination end for every IP data stream alone. The paper sets forth a kind of mixed model combining integrated Services with differentiated Services to support the VoIP QoS on the bases analysis of their defects.

Abstract: With the development of technology and the improvement of people’s living standard, more and more people purchase digital products, a multimedia website becomes an important way for people to learn how to use and maintain the digital products. The demand for knowledge about digital products use and maintenance was identified by questionnaire and interview, and then the popular science website was designed and made. From the paper, you can learn the design principles of the popular science website: properly selecting contents, using multimedia technology, clear navigation and easy to be used. This website contains the modules of computer, mobile phone, camera, DV, MP4, expert answer and forum, you can learn the basic modules and functions design, and the technical key points of implementation of the popular science website in the paper.

Abstract: Economic statistics data can exhibit the profiles of social economy phenomenon. With constantly increasing demand for analysis of the statistical data, the statistical departments are urging to find a more effective and easier way to present statistical data to users. This paper takes full advantages of the geospatial characteristics of statistical data and then presents a mixed visual analysis method to implement data process and display statistical data effectively. In order to enhance the visualization results by applying the rules of visual perception, the proposed system combines a variety of visualization techniques and coordinated multiple views together. Through the study of spatial-temporal and multivariate statistical data, users can adopt interactive techniques to further analyze the interested statistical data. The experimental results show that the proposed mixed visualization techniques are easy to discover the variation law of data and offer a fast and convenient visualization and analysis tool for statistical data.