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A method for extraction of arbitrary figure using one-dimensional histogram
Shota Nakashima,Makoto Miyauchi,Seiichi Serikawa 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
An extraction of a specific figure in image has basic problems in intelligent image sensing. The generalized Hough transform (GHT) is the representative method to extract arbitrary figures which are rotated and enlarged or reduced. Many the improvement models were also proposed. However, for extraction of arbitrary figures, it takes much processing time and needs much memory space. In addition, it is impossible to apply the GHT to figures including branches. For an improvement of the problems, a new method to extract arbitrary figure using one-dimensional histogram is proposed in this study. The method utilizes the Polytope method which is one of minimization algorithms. For the extraction of figures, one-dimensional histogram is used. The histogram has two characteristics. (1) The distribution of histogram changes if the parameters representing figure changes. (2) The best parameters are gotten, if the value of most frequency of histogram becomes maximum. Therefore, by using the Polytope method, the best parameters are searched so that the maximum value of most frequency can be maximum. In comparison with conventional method, it is understood that memory space is very small, processing time is very short and figures including branches can be extracted. In addition, this method is effective for an extraction of arbitrary figure with different aspect ratio.
HUGE DIRECT NUMERICAL SIMULATION OF TURBULENT COMBUSTION
Mamoru Tanahashi,Takehiko Seo,Makoto Sato,Akihiko Tsunemi,Toshio Miyauchi 한국전산유체공학회 2008 한국전산유체공학회지 Vol.13 No.4
Current state and perspective of DNS of turbulence and turbulent combustion are discussed with feature trend of the fastest supercomputer in the world. Based on the perspective of DNS of turbulent combustion, possibility of perfect simulations of IC engine is shown. In 2020, the perfect simulation will be realized with 30 billion grid points by 1 EXAFlops supercomputer, which requires 4 months CPU time. The CPU time will be reduced to about 4 days if several developments were achieved in the current fundamental researches. To shorten CPU time required for DNS of turbulent combustion, two numerical methods are introduced to full-explicit full-compressible DNS code. One is compact finite difference filter to reduce spatial resolution requirements and numerical oscillations in small scales, and another is well-known point-implicit scheme to avoid quite small time integration of the order of nanosecond for fully explicit DNS. A vailability and accuracy of these numerical methods have been confirmed carefully for auto-ignition, planar laminar flame and turbulent premixed flames. To realize DNS of IC engine with realistic kinetic mechanism, several DNS of elemental combustion process in IC engines has been conducted.
HUGE DIRECT NUMERICAL SIMULATION OF TURBULENT COMBUSTION - TOWARD PERFECT SIMULATION OF IC ENGINE -
Tanahashi, Mamoru,Seo, Takehiko,Sato, Makoto,Tsunemi, Akihiko,Miyauchi, Toshio Korea Society of Computational Fluids Engineering 2008 한국전산유체공학회지 Vol.13 No.4
Current state and perspective of DNS of turbulence and turbulent combustion are discussed with feature trend of the fastest supercomputer in the world. Based on the perspective of DNS of turbulent combustion, possibility of perfect simulations of IC engine is shown. In 2020, the perfect simulation will be realized with 30 billion grid points by 1EXAFlops supercomputer, which requires 4 months CPU time. The CPU time will be reduced to about 4 days if several developments were achieved in the current fundamental researches. To shorten CPU time required for DNS of turbulent combustion, two numerical methods are introduced to full-explicit full-compressible DNS code. One is compact finite difference filter to reduce spatial resolution requirements and numerical oscillations in small scales, and another is well-known point-implicit scheme to avoid quite small time integration of the order of nanosecond for fully explicit DNS. Availability and accuracy of these numerical methods have been confirmed carefully for auto-ignition, planar laminar flame and turbulent premixed flames. To realize DNS of IC engine with realistic kinetic mechanism, several DNS of elemental combustion process in IC engines has been conducted.
TADASHI HASEGAWA,TAKESHI AKASAKA,YUTAKA MAEDA,MASAHIRO HASHIMOTO,MAKOTO KANDA,TAKAHIRO TSUCHIYA,TAKATSUGU WAKAHARA,YUHEI MIYAUCHI,SHIGEO MARUYAMA,JING LU,SHIGERU NAGASE 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2007 NANO Vol.2 No.4
Single-walled carbon nanotubes (SWNTs) synthesized by catalytic decomposition of an alcohol were purified by extraction. The purified SWNTs were characterized on the basis of visible-near infrared (vis-NIR) absorption, photoluminescence and Raman spectroscopic analyses, scanning electron microscopy (SEM) observation, and thermal analysis. Selective extraction of metallic nanotubes was also achieved by the extraction condition.