All issues
Volume 43, Issue 4
Displaying 1-8 of 8 articles from this issue
- |<
- <
- 1
- >
- >|
-
Keisuke KATSUYAMA, Yoshimichi YONEZAWA, Kazunori ITOH, Masami HASHIMOT ...2007 Volume 43 Issue 4 Pages 169-176
Published: August 15, 2007
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA special interface using VEP introduced by pulsed light was examined to realize its higher speed performance. It is aimed at being used by elderly people on the bed and ALS disease patients who have difficulties using instruments around them and a computer, etc.
VEP shows the highest level when the light source for stimulation is gazed at and shows different wave forms depending on the different stimulation mode of light source. These features show a possibility of special interface which can identify the gazed light source corresponding to the selected operation in light source array.
However, this function has not been put to use generally yet, because it takes a longer time to detect the operation and has low accuracy. In the system using pulse driving light source which lights one after another, the gazed menu item can be detected by the output time of VEP. But it takes a longer time than other methods and needs some improvement. We tried the speedup of detection by introducing a method of lightening a group menu method.
A 4×4 LED matrix menu board was made as a sample to evaluate the method experimentally. This matrix is divided into 8 groups each of which consists of 4 items, that is, 4 columns and 4 rows. The 8 groups are lit one by one and shown to a subject who is gazing at one item of the menu to get VEP. As for each item, its light source lights twice with different timings in group lighting of eight times.
Using a computer, the gained VEP data is correlated one by one with a subject's standards 16 data about each item which is gained beforehand. The item whose data show maximum correlation with gained data is identified as the item which the subject selected and gazed at.
The causes of incorrect results, for example, simultaneous lighting of neighbor items, sequential lighting of the same items, were removed. This method was improved and showed the rate of correct identification of selected item, 90% for 2 second-data.View full abstractDownload PDF (8993K) -
Designing accessible Web-content for hard-of-hearingYukiko NISHIZAKI, Miki NAMATAME, Muneo KITAJIMA2007 Volume 43 Issue 4 Pages 177-184
Published: August 15, 2007
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe purpose of this study was to examine cognitive abilities of hard-of-hearing persons in information search, which is basic research aiming at solving Web-content accessibility problems for the hard-of-hearing. Most studies of Web-content accessibility for the hard-of-hearing have been limited to the issue of translating auditory information into visual information. Few studies focused on the problems hard-of-hearing have in visual text processing. Individual differences in information searching between a hard-of-hearing group and a hearing group were investigated. Participants were asked to choose one or more correct directories in response to questions in a virtual portal website. The results suggested that it was more difficult for the hard-of-hearing group to search correctly within a limited time than for the hearing group. The directories by the hard-of-hearing group choices were inconsistent, and this tendency was not related to sentence difficulties. The study findings suggest that an optimum way to design Web pages for hard-of-hearing users is to provide multiple options for a solution rather than just a single one.View full abstractDownload PDF (1205K) -
Simplified method for estimating parasympathetic nervous activity by Lorenz plot of ECG RR intervalsFumi TOYOFUKU, Kazuhiko YAMAGUCHI, Hiroshi HAGIWARA2007 Volume 43 Issue 4 Pages 185-192
Published: August 15, 2007
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSSeveral studies have been made on that the power of the high frequency components (HF) from 0.15 to 0.40Hz in heart rate variability (HRV) reflects the parasympathetic nervous activity. The purpose of this study is to show the evaluation method by applying Lorenz plot (LP) at RR intervals as a new evaluation index of the parasympathetic nervous activity. All the data of LP is plotted on the y=x axis that is the projective line. On the y=x axis, mean (m) and standard deviation (σx) of the distance from the coordinate origin are calculated. In the same way, on the y=-x axis, standard deviation (σ-x) is calculated. Ellipse area S showing variation of LP is calculated by S=π×σx×σ-x. The several phases of the experiment are performed in each subject. As a result, the significance (p<0.001) is shown between HF, m and S. The formula [y=0.592×m+0.238×S] is obtained by multiple regression analysis, and the significance (p<0.001) is shown between y and HF. This might indicate that LP is a reliable evaluation technique that takes place of HF.View full abstractDownload PDF (6798K) -
Takashi KOJIMA, Hitoshi TSUNASHIMA, Satomi ITOH, Tomoki Youke SHIOZAWA2007 Volume 43 Issue 4 Pages 193-200
Published: August 15, 2007
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSTrain drivers are strongly urged to avoid making human errors of judgment. To avoid human error in train operation, driving support systems should be developed in consideration of human behavior. In developing such systems it is important to understand the relation between the train operation and the brain activity of driver. The brain activity during the driving operation with a train simulator is measured by a functional near-infrared spectroscopy (fNIRS). To compare the changes in the brain activity with the driving operation, we developed an analysis method that can extract the brain activity related to task by using a wavelet-based multi-resolution analysis. The results show that the brain function due to a train driving can be evaluated with the proposed method.View full abstractDownload PDF (13716K) -
Kazumitsu SHINOHARA, Naoko YAMADA, Koji Kanda, Shinnosuke USUI2007 Volume 43 Issue 4 Pages 201-211
Published: August 15, 2007
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe purpose of this study was to develop a questionnaire to measure daily experiences reflecting attentional and cognitive functioning, and to examine the relation between daily attentional experiences and subjective mental workload induced by performing an attention-demanding task. The newly developed Everyday Attentional Experiences Questionnaire (EAEQ) was based on 32 items including four sub-scales: (1) the ability to concentrate; (2) the ability to control cognitive processes; (3) proneness to distraction; and (4) the tendency to perform tasks concurrently. In the subsequent experiment, 114 undergraduates took the Compound Digit Cancellation Test (CDCT), which required them to control the size of visual focused attention. Subjective mental workload was assessed before and after the experimental session, with the results indicating that participants who rated their ability to concentrate as “high” displayed a relatively high level of positivity, while those who tended to perform several tasks concurrently rated their time-related workload, general workload, and negative mood as relatively low after performing the CDCT. These results suggest that individual differences in subjective mental workload can be partly explained by the characteristics of everyday attentional experiences.View full abstractDownload PDF (8544K) -
Shin SAITO, Takahiro NAKATSUKASA, Ryojun IKEURA, Kazuki MIZUTANI2007 Volume 43 Issue 4 Pages 212-218
Published: August 15, 2007
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe aim of this study was to evaluate working conditions using multi display VDTs in terms of work performance, usability, head movement and EMG activities of the neck. A comparative study using single, dual and large display type VDT workstations, was undertaken to obtain ergonomic data applicable to the guidelines and recommendation for VDT operations using dual displays. Subjects comprised 10 healthy volunteers who performed the editing and the mouse pointing tasks for 5min on each workstation.
Work efficiency of the single display was inferior compared to dual and large displays. A Head movement was greater with dual displays than with a single and large display. EMG activities did not differ significantly in all experiment conditions.
The characteristics of a dual display type VDT work is increased efficiency, because dual and large displays can receive a lot of information and have simple operation than single display. Especially, it was suggested that a dual display reduce a load of static muscle work, because the head movement of a dual display is more than that of the large and single display by the screen extends horizontally.View full abstractDownload PDF (3137K) -
Koji OTANI, Nobutoshi YAMAZAKI2007 Volume 43 Issue 4 Pages 219-227
Published: August 15, 2007
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSTo reduce the workload of intermittent driving like a parcel delivery service driver, new automobile seat for low-speed and short time use was proposed. Easiness of standing-up and seating comfort during driving were compared by 13 male among three seat conditions: short bottom, tilt bottom, and bent bottom. As a result, it was found that the suitable bottom shape is the bent bottom which is composed with level hip part and tilt thigh part, and the maximum bottom height is 65% of the subject's crotch height. The bottom height was limited from pressure concentration on the hipbone and slip of the hip. The preferable seat shape for 11 male and 10 female was adjusted by using the experimental chair, which its seat surface shape divided into freely adjustable 16 plates. The preferred condition was as follows: depth of the hip part is 8mm, the frontal thigh part tilt 24 degrees, the backrest angle is 75 degrees from the horizontal line, and the height of convexo-lumbar part is 15mm. The preferred connecting point between hip part and frontal thigh part was near the gluteal furrow, where its body surface is flexible and relatively insensitive to pressure. Although the proposed seat condition requires another controller as a substitution of the pedal, it is possible to keep comfortable sitting about 30 minutes, and can reduce about 30% of the muscle load in stand-up motion compared with the conventional automobile seat.View full abstractDownload PDF (14249K) -
Yasuyuki MATSUURA, Hiroki TAKADA, Kiyoko YOKOYAMA, Katsuhiko SHIMADA2007 Volume 43 Issue 4 Pages 228-232
Published: August 15, 2007
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSDownload PDF (2759K)
- |<
- <
- 1
- >
- >|