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Volume 40, Issue 6
Displaying 1-6 of 6 articles from this issue
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Kaoru SUZUKI, Hiroki OCHI2004 Volume 40 Issue 6 Pages 289-301
Published: December 15, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe aim of this study is to develop a speech pre-processing system used with a public address system in a noisy environment. The pre-processing system is intended to improve the intelligibility of the public address system to assist the elderly, without increasing the sound pressure level of the voice. To examine the effectiveness of the system, an experimental system, which could not process voice in real time, was developed. Based on the output of a neural network, the system controls the compression level for each spectral band of the voice. The input of the neural network is the results of a consecutive spectral analysis of an ambient noise. In the first experiment, voice was presented to some young subjects assuming to be the elderly under several simulated noises, and they controlled the system manually to improve the intelligibility. In the second experiment, the raw voice and the voice processed by the system utilizing the neural network, which learned the results of the first experiment, were presented to both the young and the old subjects under several noises recorded at a railroad station. The intelligibility was compared between the raw and the processed voices. The results implied the effectiveness of the processing used in this study in respect to improving the intelligibility.View full abstractDownload PDF (7015K) -
Kiyoko YOKOYAMA, Noriaki KAMIYA2004 Volume 40 Issue 6 Pages 302-308
Published: December 15, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSMany reports show that the power of the high frequency components (HF) from 0.15 to 0.4Hz in a heart rate time series reflects the activity of the parasympathetic nerves. This study proposes a simple method to measure in real time and consecutively the amplitude or power of the HF of a heart rate time series. Its aim is to apply the method to devices to predict or indicate the condition of parasympathetic activity in daily life. In this paper, characteristics of the proposed method are clearly described with the use of computer simulation. Moreover, by analyzing measured data, a high correlation between the average value of HF detected with the proposed method and the HF value calculated with other frequency analysis methods (AR method and Wavelet transform) is confirmed. It is considered that this method can be applied to a daily autonomic nervous balance monitoring device, a mental stress monitor, relaxation biofeedback and the like.View full abstractDownload PDF (4293K) -
Hideki OYAMA, Yuichi EBINE, Toshihiro ANDO, Naoyuki BANDO, Masayoshi K ...2004 Volume 40 Issue 6 Pages 309-314
Published: December 15, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThis research studied the effect of physical exercise blood circulation of the lower limbs during prolonged sitting using a near infrared spectroscopy and by measuring the swelling of the foot. An experiment was performed on ten healthy, middle and old age females under two conditions: “with exercise” and “without exercise”. Under the former conditions, the subjects were made to sit for sixty minutes. The results are as follows: 1) Change in oxygenated hemoglobin (Δ oxy-Hb) in the gastrocnemius was significantly higher under the “exercise” condition than in the “without exercise” condition (p<0.05). 2) Change in the deoxygenated hemoglobin (Δ deoxy-Hb) was significantly different for the two conditions (p<0.01). In particular, Δ deoxy-Hb showed the lowest value after exercise and recovered later. 3) Foot swelling tended to be restrained under the “exercise” condition. These results suggest that venous return from the lower limbs and inflow of arterial blood increased effectively under the “exercise” condition.View full abstractDownload PDF (3229K) -
Kousuke HIRASAWA, Naoki SHIRAMATSU, Tatsuki OKAMOTO, Yukio SATO, Atsus ...2004 Volume 40 Issue 6 Pages 315-322
Published: December 15, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA new monocular HMD was developed by designing the optical system of the HMD so as to give the low divergence to the back light source, it has the unique feature of a deeper depth of focus. Some experiments were tested to determine whether changing the divergence of the back light source varies depth perception, visibility, visual fatigue, work performance, and so on. Results show that the absolute magnitude of the above evaluation indices varies appreciably by changing the divergence of the back light source.View full abstractDownload PDF (9572K) -
Mamoru TAKAMATSU, Megumi UMENO, Yoshio NAKASHIMA, Santarou NAKAJIMA, Z ...2004 Volume 40 Issue 6 Pages 323-325
Published: December 15, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThis article was retracted. See the Notification.View full abstractDownload PDF (5358K) -
2004 Volume 40 Issue 6 Pages 329
Published: 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSDownload PDF (119K)
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