The purpose of this paper is to design the manual tracking control system for simplifying the control of the plant that requires too much load of the human operator and for reducing the influence by the individual difference. The manual tracking control system was constituted from the control system using two compensators. To design these compensators by the unifying design method, it was assumed that the actual plant was perturbed from the easily controllable plant and that each human operator's control characteristics were done from the average human model. Under these assumptions, this design problem was treated as the control problem that rejects the equivalent disturbance to these perturbations. H_∞ control theory that generalized this disturbance rejection problem was applied to design compensators. As the results, the human operators become possible to control the plant for which it was difficult to do, and the similar control characteristics of the whole system were obtained independent of the human operators under the limited condition. Therefore, the validity of the applied design method and the designed compensator was confirmed experimentally. However, the improvement of the design of the control systems and weighting functions that become necessary in case of the compensator design is still left.

View full abstract

Japanese is a rare type of language in the world, using both phonological and ideographic writings. When considering education on teaching Japanese as a foreign language, it is important to research on the characteristics of Japanese reading processes. Although this has been said in general, there have been no accurate data on dynamic reading situation. In this research, we measured the eye movements of the participants reading Japanese sentences and analyzed their processes by using ergonomic methods. As a result, when reading Japanese sentences, Kanji (ideograms) plays an important role as meaning carriers and visual markers. When reading ideographic characters, a person is able to catch their graphemes easily and directly perceive their meanings without being conscious of their phonological information. When learning phonologic languages, it is more important to acquire the pronunciation of the words. On the other hand, it is more important to acquire the meanings of the words when learning ideographic languages.

View full abstract

Core temperature is one of the most important indies in the thermoregulatory responses. The tympanic temperature is accepted as a measure of core temperature in both the clinical medicine and the research on thermoregulation in humans. This paper presents a new non contact type tympanic thermometry by using a photoconductive infrared detector and a chalcogenide optical fiber. The calibration of the developed system was carried out by employing a black body which temperature is controlled by the peltier element. As a result of calibration, it is confirmed that sensor has a good linearity and dynamic response. The system has no long term drift. The system showed fluctuation in the temperature variation of 0.2°C during stability test and during thermal test for human. The system demonstrated a possibility to measure the tympanic temperature without contacting the tympanic membrane.

View full abstract

We constructed the conventional measuring system to visualize the complete cross-sectional image of human extremities using a hand-made water tank with commercial-base ultrasonographic device (3.5MHz transducer) connected to PC for graphical processing. The water tank in which the subjects can insert and fix their leg or arm, was specially designed to be able to turn and scan the ultrasound probe once around the targeted extremity every arbitrary angle to get several fragmentary graphical images of one cross-sectional plane. To assess the reproducibility of the cross-sectional image using this system, we measured the same plane of thigh in 21 subjects twice on the different days, and compared each body compositional area. There were no substantial difference or bias and the high reproducibility was confirmed. Secondly, in order to asses the system's validity, the cross-sectional images of a thigh by MRI and our developed system were compared in 10 subjects. There was a high correlation between each body compositional area as determined by both systems. It is concluded that our developed ultrasonographic system, in many respects, is superior to other imaging devices, because it is portable, safe, and inexpensive. Our system can exert these advantages in the field survey.

View full abstract

This study researched the effect of “prior verbal notice”—notice which was provided for the patient when he (she) was given head-up tilt for posture change—on the regulation of circulation system, through measuring the autonomic nervous function and cerebral circulation.
The experiment was performed on 12 healthy young subjects (six males and six females) under two conditions: “without prior notice” and “with prior notice”. Under the former condition, subjects were verbally notified when passive head-up tilt (from supine to sitting) of 70° began. Under the latter condition, subjects were given head-up tilt of 70°, while they were given verbal notice every minute, from five minutes before head-up tilt began. The results are as follows:
1) The average RR interval after head-up tilt under latter condition was lower than that under the former condition (p<0.05).
2) The LF/HF ratio before and after head-up tilt under the latter condition became significantly high about three minutes after the tilt began, compared with that under the former condition.
3) Oxy-Hb and total-Hb in the cerebral blood flow lowered due to head-up tilt. In particular, oxy-Hb showed a tendency to rise before head-up tilt under the latter condition.
This study has clarified that smoother regulation of the circulation system can be obtained if the patient anticipates head-up tilt through prior verbal notice given before it is made.

View full abstract