Hiroshi Hosaka

Learn More
Personal area networks would benefit from a wireless communication system in which a variety of information could be exchanged through wearable electronic devices and sensors. Intra-body communication using the human body as the transmission medium enables wireless communication without transmitting radio waves through the air. A human arm phantom is(More)
Comparative simulations between isotropic and anisotropic computer heart models were conducted to study the effects of myocardial anisotropy on the excitation process of the heart and on body surface electrocardiogram. The isotropic heart model includes atria, ventricles, and a special conduction system, and is electrophysiologically specified by parameters(More)
Previously it was shown that Bn, the component of the heart's magnetic field which is normal to the chest, is in large part produced directly by the generators in the heart; the volume-current (or boundary) contribution to Bn is relatively small. It was also shown that the distribution of Bn across the chest could be displayed as an arrow map which visually(More)
To understand the MCG, electrical models of the heart must be used in which the basic building-block is usually the current dipole. The dipole's magnetic field is generally made up of two parts: 1. the contribution by the dipole element itself, which is mathematically simple; 2. the contribution by the current generated in the volume conductor by the(More)
Magnetocardiograms (MCGs) of six subjects with representative cardiac abnormalities and of one well-studied normal subject are compared with the 12-lead ECGs and VCGs of these subjects. The MCGs are recordings of the component of the magnetic vector which is normal to the skin, measured across the chest on a 5 cm X 5 am grid; an example is also presented of(More)
The magnetic field produced by a current dipole is made up of two parts: the field from the dipole element, and from the current generated by the dipole in the volume conductor. It was previously shown for the semi-infinite volume conductor, infinite slab, and the sphere that the volume-current contribution is zero to the component of magnetic field which(More)
The object of this work was to develop a monitoring device for measuring the volume of urine in the bladder to signal, in advance, the need to urinate and thus help prevent urinary incontinence. A high-frequency electric current of 50 KHz transmitter was applied to a pair of terminals placed on the surface of a human body. The constant current was 2mA(More)
We developed a lifelog system that utilizes user's mobile phones. User's position, which is closely related to the user's activity and experience, is tracked by GPS in outdoors and by a newly developed positioning system utilizing signal strength of Bluetooth in indoors. The mobile phone is also equipped with a supplementary function that lets the user(More)
This paper proposes a low-distortion filter method for rejection of muscle noise in multilead electrocardiogram (ECG) systems. This approach combines low-pass filtering with a modified version of source consistency filtering. The low-pass filtering splits the raw ECG signal into a muscle-noise-free part and a muscle-noise-overlapping part. The modified(More)
Ultrasonically assisted hydrothermal synthesis of PZT thin films was performed using an ultrasonic transducer integrated into the lid of an autoclave. Direct ultrasonic irradiation of 23 W at 53 kHz was carried out during the hydrothermal synthesis at a reaction temperature of 140 degrees C for 24 h. The resultant PZT thin film was characterized using(More)