For the generation of the model in reverse engineering, a laser scanner is currently used a lot due to the fast measuring speed and high precision. Direct triangulation of data points captured from a physical object h...For the generation of the model in reverse engineering, a laser scanner is currently used a lot due to the fast measuring speed and high precision. Direct triangulation of data points captured from a physical object has a great advantage in that it can reduce the time and error in modeling process. It is important to reduce the number of data points for triangulating points with maintaining precision. To triangulate data points within a tolerance ε a new approach is developed in this paper. Different level of triangulations can be generated directly from data points using the proposed strategy that reduces and triangulates data points based on triangulation of 3D parametric surfaces. An experimental example is presented to demonstrate the effectiveness and efficiency of the proposed algorithm.展开更多
A regular edge-transitive graph is said to be semisymmetric if it is mot vertex-transitive. By Folkman [J. Combin. Theory 3 （1967）, 215-232], there is no semisymmetric graph of order 2p or 2p^2 for a prime p, and by...A regular edge-transitive graph is said to be semisymmetric if it is mot vertex-transitive. By Folkman [J. Combin. Theory 3 （1967）, 215-232], there is no semisymmetric graph of order 2p or 2p^2 for a prime p, and by Malni6 et al. [Discrete Math. 274 （2004）, 18-198], there exists a unique cubic semisymmetrie graph of order 2p3, the so called Gray graph of order 54. In this paper, it is shown that there is no connected cubic semisymmetric graph of order 4p^3 and that there exists a unique cubic semisymmetric graph of order 8p3, which is a Z2 × Z2-covering of the Gray graph.展开更多
In this paper, we investigate the equilibrium point, local and global behavior of the unique positive equilibrium point, and rate of convergence of positive solutions of following discrete biological model： Xn＋1=Xne...In this paper, we investigate the equilibrium point, local and global behavior of the unique positive equilibrium point, and rate of convergence of positive solutions of following discrete biological model： Xn＋1=Xne^ln（α）（1-Yn）,Yn＋1=（γδ-1）Yn（1＋1/γδ-1-Yn/Xn）, where parameters α,γ,δ and the initial conditions Xo, ]Io are positive real numbers. Some numerical examples are given to verify theoretical results.展开更多
Based on both white response and connotation expression are geometric progression in the most primitive grey differential equation of GM（1,1）x（k） （k）＋ ax（1） （k） = b, this paper begins with generation of the...Based on both white response and connotation expression are geometric progression in the most primitive grey differential equation of GM（1,1）x（k） （k）＋ ax（1） （k） = b, this paper begins with generation of the time response .function＇s grey derivative at discrete points. Through derivative＇s definition, establishing a new GM（1,1） by optimizing grey derivative and background value. Then, getting the best coefficient c by introducing criterion function and it has proved that the new expression has the whitened exponent law coincident property and the whitened coefficient coincident property in theory. Finally, some examples show the new model has higher prediction precision.展开更多
文摘For the generation of the model in reverse engineering, a laser scanner is currently used a lot due to the fast measuring speed and high precision. Direct triangulation of data points captured from a physical object has a great advantage in that it can reduce the time and error in modeling process. It is important to reduce the number of data points for triangulating points with maintaining precision. To triangulate data points within a tolerance ε a new approach is developed in this paper. Different level of triangulations can be generated directly from data points using the proposed strategy that reduces and triangulates data points based on triangulation of 3D parametric surfaces. An experimental example is presented to demonstrate the effectiveness and efficiency of the proposed algorithm.
基金supported by National Natural Science Foundation of China (Grant No.10871021)the Specialized Research Fund for the Doctoral Program of Higher Education in China (Grant No.20060004026)
文摘A regular edge-transitive graph is said to be semisymmetric if it is mot vertex-transitive. By Folkman [J. Combin. Theory 3 （1967）, 215-232], there is no semisymmetric graph of order 2p or 2p^2 for a prime p, and by Malni6 et al. [Discrete Math. 274 （2004）, 18-198], there exists a unique cubic semisymmetrie graph of order 2p3, the so called Gray graph of order 54. In this paper, it is shown that there is no connected cubic semisymmetric graph of order 4p^3 and that there exists a unique cubic semisymmetric graph of order 8p3, which is a Z2 × Z2-covering of the Gray graph.
文摘In this paper, we investigate the equilibrium point, local and global behavior of the unique positive equilibrium point, and rate of convergence of positive solutions of following discrete biological model： Xn＋1=Xne^ln（α）（1-Yn）,Yn＋1=（γδ-1）Yn（1＋1/γδ-1-Yn/Xn）, where parameters α,γ,δ and the initial conditions Xo, ]Io are positive real numbers. Some numerical examples are given to verify theoretical results.
文摘Based on both white response and connotation expression are geometric progression in the most primitive grey differential equation of GM（1,1）x（k） （k）＋ ax（1） （k） = b, this paper begins with generation of the time response .function＇s grey derivative at discrete points. Through derivative＇s definition, establishing a new GM（1,1） by optimizing grey derivative and background value. Then, getting the best coefficient c by introducing criterion function and it has proved that the new expression has the whitened exponent law coincident property and the whitened coefficient coincident property in theory. Finally, some examples show the new model has higher prediction precision.
