著者

多田 茂

出版者

日本ヘーゲル学会

雑誌

ヘーゲル哲学研究 (ISSN:13423703)

巻号頁・発行日

vol.1997, no.3, pp.94-97, 1997-08-11 (Released:2010-07-27)

参考文献数

2

著者

藤田 貴行 塚本 哲 多田 茂

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集C編 (ISSN:18848354)

巻号頁・発行日

vol.77, no.780, pp.3017-3024, 2011 (Released:2011-08-25)

参考文献数

35

被引用文献数

2

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1/f noises, the power spectrum density (PSD) of signals inversely proportional to the frequency, have been observed in various types of physical and physiological systems; e.g. current and heart beat. 1/f noise is suggested to be generated by superimposing stochastic processes. Among stochastic processes, autoregressive process is suitable for analyzing physical and physiological systems in that the autoregressive process is time-discrete. A time-discrete model is suitable for analyzing those systems because those systems are observed in time-discrete manner as well. However, it is obscure whether 1/f noises are generated by superimposing those autoregressive processes. In this study, first order autoregressive (AR(1)) processes were superimposed with varied the process parameter and a driving noise. As a result, PSD of superimposed time sequences was inversely proportion to the frequency when the process parameter and a driving noise were a uniformly distribution and white noises, respectively. This result suggests that 1/f noises could be generated from the superimposing AR(1) processes when the process parameter is distributed uniformly.

著者

多田 茂 大島 修造 山根 隆一郎

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.57, no.536, pp.1257-1264, 1991-04-25

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A numerical method employing physical components of the tensorial quantity as dependent variables on boundary-fitted curvilinear grids is applied to the simulation of flow in arbitrary cross-section curved pipes for an imposed pressure gradient of oscillatory nature. The basic equations are formulated for Stokes fluid. The computation for a Newtonian incompressible fluid in curved concentric annuli and curved eccentric annuli was carried out for the range 10^3 ≤ De ≤ 10^5, 1 ≤ Wo ≤ 10^2, where De is the Dean number and Wo is the Womersley number. It is found that, at very low or very high Womersley number, the amplitude of the wall shear stresses derived numerically is in good agreement with that of the zero-th order of the asymptotic expansions of the solution of concentric annuli as the curvature parameter δ tends to zero, and that 2 pairs of secondary flow appear for even low Womersley number, contrary to the case of the circular coiled tubes.