Electrocardiograms (ECGs) used for the diagnosis of heart diseases generates large amounts of time-series data. They are regarded as hyperdimensional data. The number of dimension is that of sample points. To automatically recognize any abnormality in the ECG it is essential to extract significant features from the hyperdimensional ECG data. We have already developed a method for purpose-oriented feature extraction and successfully applied it to hyperspectral data which have several hundreds of dimensions. Here we apply the basic idea of this method to the analysis of 12-lead ECGs for the discrimination of abnormal waveforms. ECG data were acquired from normal subjects and from patients who seemed to suffer from one of three classes of abnormalities (anterior myocardial infarction, inferior myocardial infarction, and flattening of the T wave). A small number of features appropriate for discriminating significant patterns of the ECG were extracted. Our method can efficiently process the data and give results relevant to the purpose of diagnosis.

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Propagation characteristics of elastic waves in a liquid crystal cell are described from the view points of numerical analysis. A periodical stripe domain pattern is induced by an interaction between the elastic wave and nematic liquid crystal and is observable via a polarized microscope. The propagation characteristics in the solid/liquid/solid trilayer are related to the material constants. The Oth mode is strongly dependent on the conditions of the liquid crystal layer, while the 1st mode is almost independent of the liquid phase condition. The Oth mode phase velocity is estimated from the period of the observed stripe domian. The evaluated obtained results in nematic liquid crystal MBBA (4'-Methoxybenzylidene-4-n-butylaniline) are in good consistency with the numerical analysis. This method has the advantage of the simplicity in evaluation and need very small amount of nematic liquid crystal.

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The magnetic field strength in the nickel rod with an applied uniform external field is studied by transmitting ultrasonic waves. In the non-destructive testing (NDT) longitudinal plane waves are transmitted from a ultrasonic transducer to the object, which is characterized by alternating regions of compression and dilation. If the objects are ferromagnetic materials, the compression waves generate the magnetoelastic energy in magnetic substances, which are equivalent to the magnetic anisotropy field. This field passes through magnetic substances with the velocity of ultrasound and is observed as the electromotive force, emf, induced in the sensing coil. As the ultrasonic waves are transmitted continuously to a rod specimen the ultrasonic stationary wave is formed in it and the high frequency magnetic field is generated in nodes of the stationary state by the inverse effect of magnetostriction and then the emf is induced in the nodes. In this paper the strength of effective magnetic field in the nickel rod is estimated by measuring the electromotive force induced in the sensing coil.

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We propose Contactless Power Station (CLPS) with spiral-type coils or cam-type coils as one of the CLPS in the sea We confirmed that the power transmission characteristics in the sea agreed well with that in the air. We calculated the mutual inductance and the self-inductance by using the Neumann's formula, which is applied by the diameters of the coils, the number of turn and the coil gap. We confirmed that the calculated values agreed well with the experimental values. Then we designed the optimum coils for the power transmission by using the calculated mutual inductance and self-inductance. We examined the coil design on the power supply of the 200[W] level to a robot in the sea by way of example.
We discwssed the relation among the coupling factor, the ratio of the coil diameter and the coil gap, and design the optimum coil design for the optimum load

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This paper describes the effect of barrier shape upon creeping discharge characteristics in SF6, N2 gas and their mixture. The dependency of interelectrode length on the flashover voltage was investigated under the negative pulse voltage. The flashover voltage increased as increasing interelectrode length. However, the flashover voltage characteristics varied greatly with changing barrier shape in N2 gas. In SF6 gas the effects of the barrier shape on interelectrode distance dependence of flashover voltage were hardly found. In order to make clear the effect of the barrier shape on creeping discharge characteristics, we observed the creeping discharge extension images by using an ultra-high speed digital framing camera (IMACON 468).

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Space charge effect on DC breakdown strength of Ethylene Vinyl-acetate Copolymer (EVA) was studied in the region of cryogenic to ambient temperatures. DC breakdown strength and pre-stressing effect on it were measured in the region of cryogenic to ambient temperatures. In addition, direct space charge measurement was carried out in the correlating temperature region using the pulsed electroacoustic method.
DC breakdown strength below 170 K was almost constant, however, it slightly increased with increasing temperature in the region of 170-230 K. This slight rise in electric strength would derive from the formation of homo space charge in front of the cathode. Above 230 K, it showed a significant drop with increasing temperature. This would be due to the formation of hetero space charge in front of the cathode.
The direct space charge measurement by pulsed electroacoustic method showed no space charge at 180 K, however, significant amount of positive charge was seen at 290 K. This positive charge would enhance the cathode field and reduce, the DC breakdown stress. The "ratio of electrode signals"; was defined in order to assess the field enhancement at cathode. The "ratio";showed almost the same temperature dependence as the breakdown strength, suggesting that the relaxation and enhancement of the cathode field by space charges significantly affect on the breakdown characteristics.

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At the performance test of power cables, it becomes an important factor to measure a large electrostatic capacitance. In such an application, it is desirable to use a standard capacitor that has the capacitance as large as the test piece. In this paper, the authors propose a method of constructing a high performance large capacitance capacitor using a microprocessor based circuit. The dielectric loss tangent of the electronically constructed 0.1 μF capacitor has been measured as less than 1×10^-5. The temperature coefficient of the electronic capacitor can easily be compensated and a temperature coefficient of less than 1 ppm/°C has been attained.

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A new magnetic force control method using giant magnetostrictive material (GMM) was proposed and its feasibility was confirmed in the former studies by the authors. This new method is based on the inverse magnetostrictive effect and the magnetic force is controlled by changing the stress or strain in the magnetostrictive material. This method was expected to have lower heat generation and higher energy conversion efficiency compared to traditional methods since constant magnetic force can be maintained by only applying constant stress. In this study, the energy conversion efficiency of this method is investigated experimentally using a universal test machine. The input elastic energy was calculated from the stress-strain loading curve and the converted magnetic energy was estimated from the generated magnetic field. Since the elastic energy is strongly dependant on history of strain-stress loading curve, and the loading curve is affected by the applied magnetic field in the magnetostrictive material, it is important to optimize the bias magnetic field for maximum energy conversion efficiency. The relationships between Young's modulus and magnetic field were measured experimentally and the results show that a bias magnetic field must be carefully chosen to obtain high efficiency of energy conversion.

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This paper describes a new direct measurement of the carrier mobility in insulating materials such as polyethylene. Polyethylene is often chemically cross linked in order to improve heat resistance, however, some cross linking by-products such as acetophenone significantly affect its electric properties. In this study, an experiment was performed to clarify how the carrier mobility is influenced by the existence of acetophenone in polyethylene. One side of a polyethylene film with 0.1-mm thick was soaked with acetophenone. Time-dependent charge distribution was monitored by the pulsed-electroacoustic method, when a "carrier excitation pulse voltage"; was superposed on a "DC bias voltage";. It was observed that a positive charge packet was injected from the anode by the excitation pulse, and moved towards the cathode being driven by the bias field. There was a good correlation between local acetophenone content and the mobility at corresponding position. It was concluded that diffusion of acetophenone leads to the increase in the mobility of the injected positive carrier, up to 3×10^-10cm²/Vs. It was also proved that the carrier mobility can be estimated by this technique, even if the specimen has a gradation in its property.

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The amorphous melt-spun ribbons of Pr-Fe-Co-Nb-B system alloys were prepared by single roller rapid-quenching method. The effect of composition, wheel velocity and heat-treatment on the magnetic properties were investigated. The amorphous Pr₉Fe₇₆Co₈Nb₁B₆ ribbon prepared at a wheel velocity of 15.0 m/s were crystallized by heat-treatment, and the optimum heat-treatment condition was found to be at 700°C for 0 min, then the value of (BH)_max was 146.2kJ/m³. The temperature coefficients of Jr and HcJ for the ribbons crystallized from the amorphous Pr₉Fe₇₆Co₈Nb₁B₆ alloy were α(Jr)=-0.05%/°C (reversible) and α(HcJ)=-0.45%/°C (irreversible), respectively. The value of (BH)_max for the compression molding Pr₉Fe₇₆Co₈Nb₁B₆ isotropic bonded magnet prepared by using the ribbons annealed at 700°C for 0 min is 84.5kJ/m³ and the density is 6.1Mg/m³.

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Sea clutter was measured using an X-band radar with a frequency of 9, 380MHz. Various CFAR systems were already considered for clutter which depends on the distribution. In order to apply a CFAR system to non-distributed sea clutter, we used Non-Parametric CFAR techniques. By using Second Central Moment Procedure, we succeed in suppression of sea clutter and detect ion of targets.

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The paper reports electrical resistances of a human body in various conditions when the impulse voltages were released from a stun gun. The resistance values of 500 to 1000 Ω were computed from the transient ratio of the current to the impulse voltage up to 3.5 kV.

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This paper describes the results of an experiment in which the surface discharge initiation phenomenon is caused by the attached charge itself.We initiated the surface discharge by attaching an electrical charge to a film surface covered plane electrode using a needle electrode and lowering pressure. At a critical pressure, a ring-shaped discharge monentarily appears around the center of the attached charge. The relationship between the critical pressure and the tangential electric field is discussed with results indicating.

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The transient potential distribution on an insulating material with a surface discharge and a subsequent back-discharge is measured with high resolution of time and space by using Pockels sensing system. It is proved that a part of electrical charges, which are generated due to a surface dishcarge and accumulated near a high-potential electrode, flow back into the electrode with a subsequent back-discharge.

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Analytical solution of a resistive cable's unit step response is derived and its advantage in accuracy over the approximated discrete circuit is also demonstrated in the paper. A simulation using a resistive cable for the field-probe measurement confirms that reciprocating reflexion caused by impedance miss-matching, which otherwise superposes over measured signal, can be damped and almost distortion-free signal can be obtained at the recording device's input.

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Our visual characteristics are affected by various visual environments. In this experiment, we examine how object colors look in dense fog. Namely, 5 subjects with normal color vision evaluated their color perception of object color both in the presence of fog and in the absence of fog at various illuminance levels. Subject's task is to match the apparent color of 10 standard-color-cards in dense fog with the Munsell color. In the presence of fog, apparent color showed a drastically decrease both in the chroma and in the value. Namely, their color perception shift from chromatic color to achromatic color. This tendency becomes more conspicuous as the surface illuminance level diminishes.

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In this paper, I have investigated relationship between partial discharge (PD) in a simulated tree channel and tree growth of fatigue failure type from its tip at temperature range from 20°C to 70°C. Voltage dependence of total number of PD pulses in voltage range where shape-parameter m in Weibull distribution was m_??_1 was obtained. Relationship between total number of PD pulse n and applied voltage V is represented by n∝V^-α for each temperature. The exponents α do not change with temperature rise. Ahrrenus plot of total number of PD pulses allows to estimate activated energy to be 4.7kcal/mol. This value is less than chemical bonding energy of polymer chain such as C-C and C-H bonds, but is in good accord with physical one such as van der Waals force between CH₃ bonds.

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