Tomoo Kamakura

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A planar object can be levitated stably close to a piston sound source by making use of acoustic radiation pressure. This phenomenon is called near-field acoustic levitation [Y. Hashimoto et al., J. Acoust. Soc. Am. 100, 2057-2061 (1996)]. In the present article, the levitation distance is predicted theoretically by numerically solving basic equations in a(More)
(2014). Spatial aliasing effects in a steerable parametric loudspeaker for stereophonic sound reproduction. IEICE transactions on fundamentals of electronics, communications and computer sciences, E97-A(9), 1859-1866. or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic(More)
This paper proposes a new method for automatically detecting the states of the road surface from tire noises of vehicles. The methods are based on a Fast Fourier Transform analysis, an artificial neural network, and the mathematical theory of evidence. The proposed classification is carried out in sets of multiple neural networks using the learning vector(More)
Acoustic radiation force (ARF) has been recently used for the tissue elasticity measurement and imaging. On the other hand, it is predicted that the higher temperature rises occur. In vivo measurement of temperature rise in animal experiments is important, whereas the measurement using thermocouples have some problems such as position mismatch of a(More)
We herein propose a new theoretical approach for analyzing the nonlinear propagation of directive sound beams emitted from a planar piston source with a circular aperture. The proposed approach relies on the split-step Padé approximation, which is an efficient method for obtaining wide-angle one-way wave equations, especially in underwater acoustics.(More)
Underwater ultrasonic devices applying Doppler effects use a constant sound speed as the average speed. However, the sound speed in the sea varies with water depth and an assumed constant sound speed has the potential to cause measuring errors. Moreover, because the sea current, which is the moving speed of a propagating medium, substantially changes the(More)
OBJECTIVE The blood-brain barrier (BBB) limits the entry of some therapeutics into the brain, resulting in reduced efficacy. BBB-opening techniques have been developed to enhance the entry into the brain. However, a noninvasive, highly sensitive and quantitative method for evaluating the changes in BBB permeability induced by such techniques is needed to(More)
Field characterization methods using a scattering target in the absence of a point-like receiver have been well described, in which scattering is recorded by a relatively large receiver located outside the field of measurement. Unfortunately, such methods are prone to artifacts caused by averaging across the receiver surface. To avoid this problem while(More)
The parametric loudspeaker is a type of directional loudspeakers making use of the nonlinear acoustic effects. The past studies to reproduce the three-dimensional audio contents with a pair of the parametric loudspeakers have demonstrated satisfactory performance. In this paper, the steerable parametric loudspeakers are proposed to relocate the sweet spot(More)
The concave spherically annular transducer is regarded as a negative and a positive concave spherical transducer, and the spheroidal beam equation is used to simulate the linear and nonlinear sound field in a tissue medium generated by this transducer. It is found that the acoustic focus of the ring does not coincide with the acoustic focus of its central(More)