It is known that convergence rate of Domain Decomposition Method for finite element analysis depends on the mesh decomposition quality. In this study, a new approach for refinement algorithm to be employed in mesh segmentation is presented Method is based on multilevel quadrisection and octasection graph partitioning. In this method, the connection is guaranteed first by detecting the disconnected parts and then through the algorithm, assigning them to the domain which mostly contain the mesh of interest. Hence the resulting mesh structure has an improved quality with less number of nodes at the interface of subdomains yielding a decrease in the computational time. Method proposed in the paper is illustrated on a large scale urban noise pollution. The noise pollution model of the neighborhood of Tokyo Shibuya Train Station is obtained by using non-overlapping optimized Schwarz and it is seen that the proposed method reduce number of iterations and thus computation time significantly.

抄録全体を表示

The development of micro machining technologies results in the wide use of optical interference measurement methods to evaluate surface configurations with micro/nanometer scale accuracy. The measurement range in vertical direction of the former optical interferometry with a single-wavelength was limited to the half of the wavelength. Though the phase unwrapping method is applied to expand the range, the usual high-speed phase unwrapping algorithms are sensitive to such noise as digital errors at A/D conversion of the interference fringe brightness. In this paper, we propose a newly algorithm to unwrap the phase after reducing the noise by interpolating the interference fringe images. Then, the performance of proposed algorism is verified through a numerical simulation and experiments using a high precision steel ball. The effective way to measure a high precision surface with deep slope is expanding the measurement range by combining the arctangent operation and the phase wrapping after applying a cubic spline interpolation to the interference fringe images. A portable single-wavelength interferometry measurement system with the developed algorithm is suitable for measuring a smooth surface like a precision steel ball without partial gaps.

抄録全体を表示