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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Ergonomics Society of Korea
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The Ergonomics Society of Korea
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Volume & Issues
Volume 13, Issue 2 - Aug 1994
Volume 13, Issue 1 - Apr 1994
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Analysis of human gait using inverse kinematics
Journal of the Ergonomics Society of Korea, volume 13, issue 1, 1994, Pages 3~14
In this study, the human gait trajectories during normal walking were synthesized using the inverse kinematics and optimization techniques. The synthesis is based on a gait model consisting of a torso and two legs. Each let has three segments: thigh, shank, foot, and has six degrees-of-freedom. In order to synthesize trajectories of this redundant system, the sum of angular displacements of articulating joints was selected as an objective function to be minimized. The proposed algorithm in this study is very useful for the analysis of human gait. For the gait analysis, the trajectories of four points in each leg should be measured. Hpwever, by using the algorithm, measuring the trajectories of two points is sufficient, and thus the experimental set-up can be simplified.
Safety belt effectiveness versus crash types
Park, S.G. ;
Journal of the Ergonomics Society of Korea, volume 13, issue 1, 1994, Pages 15~25
Based on Fatal Accident Reporting System (FARS) data, safety belt effect- tiveness in preventing fatalities is investigated for the following five types of crashes: frontal, left, rear, right, and rollover. Passenger cars containing two occupants, a driver and a right front passenger, are included in this analysis. For each crash type, these cars containing the two occupants are classified into four categories according to the safety belt usage categories for the two front seat occupants, namely, both belted, both unbelted, and either one was belted but not both. Relative risks of driver and right front passenger fatalities are compared among these four cases. For each crash type, two independent estimates of safety belt effectiveness are obtained for drivers and for right front passengers. The weighted average of the two estimates is calculated for drivers and for right front passengers for the five crash types. Using FARS data starting 1978 throught 1983, safety belts are more effective in rollover accidents than in frontal collisions. In rollover accidents, safety belt effectiveness estimate for drivers is
and that for right front passengers is
, in which the error limits indicate one standard error. Sfety belt effectiveness estimates for drivers and right front passengers involved in frontal collisions are
, respectively. For left and right sided collisions and for both drivers and right-front-passengers, none of the four estimates are significantly different from 0%, statistically : however, when left and right sided collisions are combined with far sided occupants(drivers involved in right sided collisions and right front passengers involved in left sided collisions) safety belt effectiveness is significant,
. For rear collisions, the estimate for drivers shows statistically significant positive effect,
. while for right-front-passengers the estimate is not significantly different from 0%. These results show that a safety belt is an effective restraint system not only in frontal crashes but also in a variety of crashes.
Effects of stimuli and reaction methods on error rate and time of choice reaction
Journal of the Ergonomics Society of Korea, volume 13, issue 1, 1994, Pages 27~35
Automation and mechanization of work make people put the machine into operation and control the state of operation. In the process of those works they are apt to have accidents caused by their carelessness. To reduce such accidents, we can practice "TOUCH '||'&'||' CALL", which is to indicate and ascertain the dangerous parts at every process before performing tasks. The objectives of this study are to examine the effects of S-R compatibility and to show quantitatively the efficiency of TOUCH '||'&'||' CALL. The results show that: 1. Reaction time in case of indicating with fingers and shouting is slightly longer (0.138sec. .approx. 0.279sec. ) than that of responding only visually. However, the error rate decreases by 1/3.3 .approx. 1/4.2 times. Frome this, it is considered to verify quantitative estimation on multiple feedback of TOUCH '||'&'||' CALL. 2. In the stimulus-response relation aspect, numeric numeric stimulus-numeric response shows lower error rate (0.033% .approx. 0.133%) than any other stimulus-response relation, ahd shorter reaction time is proven ( 0.556sec. .approx. 0.835sec. ). These data suggest that having the order of stimulus-response arranged in accordance with the experimental knowledges and conceptional compatibility can bring down the error rate considerably.
The accuracy of the depth perception of 3-dimensional images
Journal of the Ergonomics Society of Korea, volume 13, issue 1, 1994, Pages 37~46
The accurate error size and discrimination region in the perception of depth amount from 3-dimensional images by the human visual system will be the basic data for the utilization and application of the binocular 3- eimensional image system. This paper is focused on studying the accuracy of the depth amount perceived from 3- dimensional images by the human visual system. From the performed experiment, the following results have been obtained: (1) The depth amount perceived from the binocular 3- dimensional images has been displayed by a proper scale of distance, and found to be imprecise and also have a large variance. (2) In utilizing the binocular 3-dimensional image system, it seems more appropriate to make the images viewed outward rather than inward from the screen in the regard of error and variance. (3) The binocular 3-dimensional image system can be effectively applied to displaying unreal space, for example, the layout of room in design, from the viewpoint of perception characteristics of depth amount.
Body composition and measurement of subcutaneous fat thickness by ultrasonic method
Journal of the Ergonomics Society of Korea, volume 13, issue 1, 1994, Pages 47~58
The purpose of this study was to obtain the basic data for a design for comfort wear. The subjects of this study were 197 women's university stu- dents. The characteristics of their body types and the thickness of subcuta- neous fat at eight body sites were measured. The thickness of subcutaneous fat was measured by both Ultrasonics and with a Skinfold Caliper. The cor- relation between their values and the thickness of subcutaneous fat were compared. The relationship between Rohrer Index and the subject's self- conception of their body was also compared. The results were as follows: 1. The measurement of thickness of subcutaneous fat at triceps and scapula was a little lower, in using Skinfold Caliper method, than Ultrasonics method because of the pressure of the caliper. 2. Correlation between percentage of fat in body and body characteristics was high in order of chest girth > weight > abdomen girth. 3. The thickness of subcutaneous 8 body these sites was high in order of thigh > triceps > scapula > abdomen > suprailiac > chest > calf > forearm. Percentage of body fat has a positive correlation with both average thickness of subcutaneous fat and thickness of subcutaneous fat at triceps. 4. Rohrer Index shows a positive correlation between average thickness of subcutaneous fat and percentage of body fat. 5. About half of subjects of this study thought that they were obese although the data proved otherwise.
A study on the apparel sizing system of adult women
Journal of the Ergonomics Society of Korea, volume 13, issue 1, 1994, Pages 59~74
The purposes of this paper were to suggest the procedures for a sizing sys- tem which can provide good fitting of apparel and minimize the loss due to excessive inventory, and to determine an adequate apparel sizing standard. An anthropometric database used for this study was the 1992 National Anthro- pometric Survey of Koreans. The database was limited to 1,336 women who were 18-51 years old. They study was conducted by classifying ages into two groups (18-33, 34-51) using Wilk's lamda. Three principal components : laterality( fullness), linearity(length) and characteristic of torso were selected to describe body types, and these three body type classification of each group were selected by cluster analysis. It was found that all intervals between standard sizes were not equal. They were narrow around the center with high frequencies of the customers but wide in both tail with low frequencies. It was also found that the optimal sizes suing the loss function can be applied well in practice.