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Search Results: 1 - 10 of 4288 matches for " Takashi Takiguchi "
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Proposal to Study Uniqueness Problem of Rayleigh Wave in Half-Space Kelvin Viscoelastic Media  [PDF]
Hua Cheng, Takashi Takiguchi
Journal of Applied Mathematics and Physics (JAMP) , 2019, DOI: 10.4236/jamp.2019.79142
Abstract: Rayleigh wave is an interference wave of longitudinal wave and transverse wave which propagate along the free surface of solids. There remains a dispute about the number of Rayleigh waves in viscoelastic media until now, which is an essential problem of Rayleigh wave propagation. The purpose of this study is to propose a brief way of handling this essential problem within half-space Kelvin viscoelastic media. Starting from the dynamic equations of transverse wave and longitudinal wave based on Kelvin viscoelastic model, this study sets the complex wave number as a variable, introduces complex moduli and complex exponential factors, then a characteristic equation of Kelvin viscoelastic Rayleigh wave in half space is derived and simplified support for analysis of its uniqueness. After reviewing mathematical models describing phenomena of having multiple solutions but uniqueness when a natural condition is taken into account, a conjecture is given that the Rayleigh wave in Kelvin viscoelastic media must be unique if we assume a natural condition in accordance with the natural phenomena.
Autologous antibody to src-homology 3-domain GRB2-like 1 specifically increases in the sera of patients with low-grade gliomas
Matsutani Tomoo,Hiwasa Takaki,Takiguchi Masaki,Oide Takashi
Journal of Experimental & Clinical Cancer Research , 2012, DOI: 10.1186/1756-9966-31-85
Abstract: Background Glioma is the most common primary malignant central nervous system tumor in adult, and is usually not curable in spite of various therapeutic approaches. Clarification of the oncogenic process in its early stage is important for the diagnosis and effective therapy. Methods In the present study, we used the serological identification of antigens by recombinant cDNA expression cloning (SEREX) to explore the subtle changes of the protein expression in low-grade glioma. The levels of serum autoantibodies to the SEREX-identified glioma-related antigens were analyzed by ELISA, and the epitope site was identified using deletion mutants and overlap peptide array. Changes in the serum autoantibody levels were examined in the rat glioma model using C6 and 9 L glioma cell lines. Results We identified 31 glioma-related antigens by SEREX. Among them, the serum level of autoantibody to src-homology 3-domain GRB2-like 1 (SH3GL1) was significantly higher in patients with low-grade glioma than healthy volunteers or high-grade gliomas. The 10 amino-acids at the C-terminal were identified as the epitope site by the overlap peptide array and the ELISA using deletion mutants. The tissue expression of SH3GL1 protein increased in proportion to glioma progression. The rat glioma models confirmed the increase of anti-SH3GL1 autoantibody level in the early stage and the suppression in the late stage. Conclusion SH3GL1 may be involved in the oncogenic process of gliomas and effectively elicit an autologous antibody response in low-grade gliomas. The immunological reaction to SH3GL1 would contribute to the establishment of a novel diagnostic and therapeutic target for gliomas.
Sudden Noise Reduction Based on GMM with Noise Power Estimation  [PDF]
Nobuyuki Miyake, Tetsuya Takiguchi, Yasuo Ariki
Journal of Software Engineering and Applications (JSEA) , 2010, DOI: 10.4236/jsea.2010.34039
Abstract: This paper describes a method for reducing sudden noise using noise detection and classification methods, and noise power estimation. Sudden noise detection and classification have been dealt with in our previous study. In this paper, GMM-based noise reduction is performed using the detection and classification results. As a result of classification, we can determine the kind of noise we are dealing with, but the power is unknown. In this paper, this problem is solved by combining an estimation of noise power with the noise reduction method. In our experiments, the proposed method achieved good performance for recognition of utterances overlapped by sudden noises.
Effect of Nitrogen Source on Biomass and Lipid Production of a Marine Microalga, Nannochloropsis oceanica IMET1  [PDF]
Yongxue Chi, Feng Chen, Yasuyuki Takiguchi
Green and Sustainable Chemistry (GSC) , 2015, DOI: 10.4236/gsc.2015.52013
Abstract: The effects of the nitrogen sources sodium nitrate (NaNO3) and urea (CH4N2O) on growth, lipid production, and fatty acid composition of Nannochloropsis oceanica IMET1 were investigated. Nitrogen source affected cell density, dry cell weight, and lipid production. Cells grown in the nitrate medium increased dry cell weight and lipid weight in comparison with cells grown in the urea medium. The composition of fatty acids varied with nitrogen sources. IMET1cultured in the nitrate medium mainly contained C18:2 (14.9%) and C16:0 (6.3%) fatty acids, while IMET1 in the urea medium mainly contained C22:0 (33.1%), C18:3 (8.6%), and C16:0 (6.8%). This study demonstrates that nitrogen source can strongly influence lipid production and composition of N. oceanica IMET1.
The More Attractive, the Less Deceptive? Effects of Female Facial Attractiveness on Perceived Deceptiveness  [PDF]
Jun’ichiro Murai, Izuru Nose, Yuuta Takiguchi
Psychology (PSYCH) , 2018, DOI: 10.4236/psych.2018.94032
Abstract: We examined whether the facial attractiveness of females affects their perceived deceptiveness. We recorded three female models as they responded to 15 self-introductory interview questions while wearing makeup to make them look more and less attractive. The video clips were presented in high versus low attractiveness conditions to adolescent participants (both males and females), who rated the model’s attractiveness and deceptiveness after her reply to each of the questions. Two of the models in the high attractiveness condition were rated as significantly more attractive. Two-way ANOVAs on the deceptiveness ratings of each reply revealed that deceptiveness was generally, but not strongly, lower in the high attractiveness condition than in the low attractiveness condition. The present technique of manipulating facial attractiveness is applicable to future research.
PCA-Based Speech Enhancement for Distorted Speech Recognition
Tetsuya Takiguchi,Yasuo Ariki
Journal of Multimedia , 2007, DOI: 10.4304/jmm.2.5.13-18
Abstract: We investigated a robust speech feature extraction method using kernel PCA (Principal Component Analysis) for distorted speech recognition. Kernel PCA has been suggested for various image processing tasks requiring an image model, such as denoising, where a noise-free image is constructed from a noisy input image. Much research for robust speech feature extraction has been done, but it remains difficult to completely remove additive or convolution noise (distortion). The most commonly used noise-removal techniques are based on the spectraldomain operation, and then for speech recognition, the MFCC (Mel Frequency Cepstral Coefficient) is computed, where DCT (Discrete Cosine Transform) is applied to the mel-scale filter bank output. This paper describes a new PCA-based speech enhancement algorithm using kernel PCA instead of DCT, where the main speech element is projected onto low-order features, while the noise or distortion element is projected onto high-order features. Its effectiveness is confirmed by word recognition experiments on distorted speech.
3D Human Pose Estimation from a Monocular Image Using Model Fitting in Eigenspaces  [PDF]
Geli Bo, Katsunori Onishi, Tetsuya Takiguchi, Yasuo Ariki
Journal of Software Engineering and Applications (JSEA) , 2010, DOI: 10.4236/jsea.2010.311125
Abstract: Generally, there are two approaches for solving the problem of human pose estimation from monocular images. One is the learning-based approach, and the other is the model-based approach. The former method can estimate the poses rapidly but has the disadvantage of low estimation accuracy. While the latter method is able to accurately estimate the poses, its computational cost is high. In this paper, we propose a method to integrate the learning-based and model-based approaches to improve the estimation precision. In the learning-based approach, we use regression analysis to model the mapping from visual observations to human poses. In the model-based approach, a particle filter is employed on the results of regression analysis. To solve the curse of the dimensionality problem, the eigenspace of each motion is learned using Principal Component Analysis (PCA). Finally, the proposed method was estimated using the CMU Graphics Lab Motion Capture Database. The RMS error of human joint angles was 6.2 degrees using our method, an improvement of up to 0.9 degrees compared to the method without eigenspaces.
Direct Preparation of Hydrogen and Carbon Nanotubes by Microwave Plasma Decomposition of Methane over Fe/Si Activated by Biased Hydrogen Plasma  [PDF]
Katsuya Konno, Kaoru Onoe, Yasuyuki Takiguchi, Tatsuaki Yamaguchi
Green and Sustainable Chemistry (GSC) , 2013, DOI: 10.4236/gsc.2013.31004

Methane was decomposed to hydrogen and carbon nanotubes (CNTs) by microwave plasma, using Fe/Si catalyst activated by biased (150 V) hydrogen plasma for various treatment times. Upon exposure to biased hydrogen plasma, the catalyst surface becomes lumpy within 1 min, coheres between 5 and 10 min and forms particles after 20 min. The methane conversion increased up to 93% over the treatment time of 5 min. The hydrogen yield showed as similar tendency as the methane conversion and kept 83% at treatment time of 5 min. The treatment time up to 1 min increased the amount of deposited carbon, and after treatment time of 5 min it dropped; then again after treatment time of 20 min, it increased to reach a maximum value of 22 gc/gcat. Deposited carbon was found to be consisted of carbon nanotubes. It grew vertically on the catalyst surface and reached a maximum length of 30.7 nm after treatment time of 10 min. Multiple types of CNTs were present, and the CNT diameters decreased with increasing plasma treatment time.

Mixed Music Analysis with Extended Specmurt  [PDF]
Daiki Nishimura, Toru Nakashika, Tetsuya Takiguchi, Yasuo Ariki
Journal of Software Engineering and Applications (JSEA) , 2013, DOI: 10.4236/jsea.2013.65034

This paper introduces a mixed music analysis method using extended specmurt analysis. Conventional specmurt can only analyze a multi-pitch music signal from a single instrument and cannot analyze a mixed music signal that has several different types of instruments being played at the same time. To analyze a mixed music signal, extended specmurt is proposed. We regard the observed spectrum extracted from the mixed music as the summation of the observed spectra corresponding to each instrument. The mixed music has as many unknown fundamental frequency distributions as the number of instruments since the observed spectrum of a single instrument can be expressed as a convolution of the common harmonic structure and the fundamental frequency distribution. The relation among the observed spectrum, the common harmonic structure and the fundamental frequency distribution is transformed into a matrix representation in order to obtain the unknown fundamental frequency distributions. The equation is called extended specmurt, and the matrix of unknown components can be obtained by using a pseudo inverse matrix. The experimental result shows the effectiveness of the proposed method.

Numerical Simulation of Flow over an Open Cavity with Self-Sustained Oscillation Mode Switching  [PDF]
Takashi Yoshida, Takashi Watanabe
Open Journal of Fluid Dynamics (OJFD) , 2016, DOI: 10.4236/ojfd.2016.64027
Abstract: Numerical simulations are used to investigate the self-sustained oscillating flows past an open cavity. The two-dimensional incompressible Navier-Stokes equations are solved directly by using the finite difference method for cavities with an upstream laminar boundary layer. A series of simulations are performed for a variety of cavity length-to-depth ratio. The results show the switching among some flow modes including non-oscillation mode, shear layer mode and wake mode. The variation of the Strouhal number is in favorable agreement with available experimental data. The results of flow fields in the cavity reveal the relationship between the cavity shear layer oscillation modes and recirculating vortices in the cavity.
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