The authors have developed a new method of 3-dimensional display of CT images of human brain. Many former researchs on 3-D display of CT images have employed displaying surfaces of components, such as hematoma or ventricle, for example, extracted using image processing techniques. But those components are not sufficiently reliable because their grey levels (CT levels) differ little from those of the surrounding tissues.
The method we propose applies image processing only for the skull surface whose grey levels differ widely from other tissues and display the surface combined with an original image and a reconstructed image of arbitrary direction. Hence the result is highly reliable and the full automatic processing by computer is possible.
In addition, the whole procedure can be implemented using a rather small computer according to some contrivances on hidden surface elimination and so on.

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This paper deals with the development of the new model of Above-Knee (A/K) prosthesis WLP-5 system, which can be adaptable to voluntary walking period. First, simulational analysis of the swing phase locomotion of A/K prosthesis on level walking was performed, the results of which revealed that the A/K prosthesis must have following performances to be used in amputee's voluntary walking period. One is the performance that can change the damping coefficient of knee joint rotation. The other is the ability to generate a little driving torque during a swing phase. From these results, the new model of A/K prosthesis WLP-5 system having these two functions was developed.
The WLP-5 system has the following mechanisms:
1) The mechanism to change the damping coefficient of the knee joint rotation by adjusting a needle valve regulated by a DC motor.
2) The mechanism to generate a little driving torque by self-accumulated air which is compressed by rotation of an ankle joint during a stance phase.
From the results of the walking experiments with amputees, it was confirmed that the WLP-5 system generated adequate knee-torque with a wide range of walking period (1.6-2.2sec) during the level walking.

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This paper deals with an attempt at predicting the walking period of the next step by using myoelectrogram (EMG). In order to control an above-knee prosthesis that can change its damping coefficient of a knee-joint according to walking period on level walking, walking period must be predicted precisely during the last walking-cycle. Hence, an attempt at predicting the walking period of the next step by using EMG picked up at the timing of Heel-ON, has been made. The surface differential electrode with pre-amplifier and filtering circuit, with high-CMRR and low-power consumption was developed. The best EMG data-composing method to transmit the walking period-information was developed. The walking period prediction algorism to predict the walking period of the next step was designed, and its effectiveness was confirmed with amputee's walking experiments.

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The purpose of this study was to examine the appearance of the bimodal force curve during a rapid voluntary movement. The subjects used in this study were five healthy males. A voluntary maximal elbow extension to visual stimulus was adopted as a rapid movement. The dynamic force required to extend the elbow was measured at the wrist with a tension transducer. The surface EMG was recorded from the triceps brachii muscle by means of small circular disc electrodes.
The mean value of occurrence of the bimodal force curve was 60% with a light load, and it had a decreasing tendency as the load increased. There was positive correlation coefficient between the rate of force drop and F'_max of the bimodal force curve. It was found that the bimodal force curve was hardly affected by the change of elbow angle.
From these results, the appearance of the bimodal force curve was discussed with respect to the following;
1) The visco-elastic properties of muscle.
2) The synergy of elbow extensors.
3) The inhibitory phenomenon caused by spinal reflex.

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Indentations of the needle from the skin surface to the depth where prick pain sensation is first felt, indentation threshold, have been measured as a parameter of the threshold of pain sensation of human subjects.
When the skin is stimulated spatially at random, the distribution of indentation threshold becomes unimodal and of skewed distribution. Applying psychometrical technique, it was found that higher threshold points have weeker pain intensity. Experiments on various indentation velocities showed that faster indentations generate sharp pain sensation but higher threshold amplitude, while slower indentations generate weak pain sensation and lower threshold. This difference of threshold amplitude means that there must be some factors of lag time. In the case of stepwise indentation in short period, the influence of such indentation fluctuation was not significantly observed on thresholds. In order to see the dependency on the onset or stop of indentation movement, stepwise indentation in long period was also examined. Histograms of reaction time from the latest onset of indentation movement showed that the subjects was apt to feel pain 1-2 seconds after the movement was started.
A simple one-dimensional vasco-elastic model, including springs, a dashpot and a mass, of the skin was introduced to explain the lag time and the tendency of reaction time observed in the experiments. From this, pain sensation on the skin is considered to be related to the deformation of inner part of the skin.

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A new device to measure the critical-fusion frequency (CFF) has been developed. In conventional methods, a light-source is set in a proper background and is made on-and-off. By such a type of equipment, measurement during work is difficult, since the examinee have to look into a dark box. The equipment is large in size, because the equipment includes some mechanical moving parts. In the proposed equipment, natural light is used as a source, which is modulated by a liquid crystal. This new equipment is small in size and makes possible the measurement of CFF during work, since a flickering spot appears in the open visual field of the examinee. A liquid crystal has been developed for this purpose with the response times of 1ms from clear to dark state and 8ms from dark to clear state, which is enough to measure ordinary CFF ranging up to 50Hz.

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