• Journal of the Korean Society of Mechanical Technology
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• v.13 no.3
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• pp.7-16
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• 2011

This study proposes the compensation method for the mechanical deflection error of a SCARA robot. While most studies on the related subject have dealt with the development of a control algorithm for improvement of robot accuracy, this study presents the control method reflecting the mechanical deflection error which is predicted in advance. The deflection at the end of the gripper of SCARA robot is caused by the self-weights and payloads of Arm 1, Arm 2 and quill. If the deflection is constant even though robot's posture and payload vary, there may not be a big problem on robot accuracy because repetitive accuracy, that is relative accuracy, is more important than absolute accuracy in robot. The deflection in the end of the gripper varies as robot's posture and payload change. That's why the moments $M_x$, $M_y$ and $M_z$ working on every joint of a robot vary with robot's posture and payload size. This study suggests the compensation method which predicts the deflection in advance with the variations in robot's posture and payload using neural network. To do this, I chose the posture of robot and the payloads at random, found the deflections by the FEM analysis, and then on the basis of this data, made compensation possible by predicting deflections in advance successively with the variations in robot's posture and payload through neural network learning.

• Korean Journal of Human Ecology
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• v.6 no.2
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• pp.121-131
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• 1997

This study was to design the clean room garment which fits for a body and adjusts well to the action. We examined the body's changes in action through a body measurment and made a sample of the clean room garment to which had adapted the body's changes in action and evaluated the function and the appearance compared with the existing the clean room garment. The followings were summery of the results : 1. Back intersyce breadth decreased, trunk length increased and the other parts were not change. At a posture of raising hands($M_3$) in comparison with an upright posture($M_0$). Back intersyce breadth, hip length and knee length increased and the other parts were a little change. At a bowing posture($M_2$) in comparison with an upright posture($M_0$). Back hip girth, knee length, hip length and leg length increased and the other parts were not change. At a working posture on a chair($M_1$) in comparison with an upright posture($M_0$). 2. The overall clean room garment was made increasing on the changes of part of a body through measuring and body measurement. 3. From the test of the function, it became known that the devised clean room garment was superior to the existing one in the parts of neck, shoulder, armpit and elbow at a working posture on a chair($M_1$), in the parts of neck, shoulder, and armpit at a bowing posture($M_2$), and the armpit at a posture of raising hands($M_3$). The appearance was better on the whole. 4. From the examination of photographs, the waist line of the devised clean room garment was not so much pulled up as that of the existing one on moving. And when sitting down on a chair, the waist line of the existing one was pulled down while that of the devised one had no change. As above, we investigated the actual conditions of wearing the clean room garment and measured the body's changes according the various actions. So we applied these results to the devised clean room garment but we couldn't research the clean mom effect of it owing to not obtaining the measuring instrument. The aspect of ergonomics liked the feeling of wearing and fitted to the action must be given consideration to the clean room garment, and simultaneously the dust-resistant effect must be taken into consideration in order to improve the quality of the goods. Therefore, we think it should be continued the research on the dust-resistant effect, material, washing method, quality control, and size along with the aspect of ergonomics.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.101-110
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• 2014

This study tried to identify the effects of ergonomic risk factors for absence from work of fire fighters in Korea. A self-administered questionnaire was prepared for this study. The questionnaire consisted of several parts such as 'general information', 'work-related factors', 'physical & chemical risk factors', 'ergonomic risk factors', and 'absence information'. A total of 7,098 fire fighters participated in this study. The data obtained from the survey was mainly analyzed by logistic regression. A total of 856 out of 7,098 fire fighters experienced absence from work. The risk factors such as gender, age, marital status, education level, total work year, work area. position, job rotation, noise, dust, organic solvent, skin contact with chemical substance, toxic waste, regional vibration, manual material handling, continuous standing posture, awkward working posture were associated with absence from work. Specifically, awkward working posture and manual material handling from ergonomic risk factors were major risk factors for absence from work.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.139-149
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• 2000

This study aims to review and assess the existing postural classification schemes used for evaluating postural loads in industry. The schemes can be classified into three categories: self-report, observational and instrument-based techniques depending upon how to record working postures. Of the three techniques, this study was mainly focused on the observational methods. The observational technique is most widely used in the industrial sites because it does not interfere with work, and is easy and simple to use and cost-effective without requiring the use of expensive equipment for estimating the angular deviation of a body segment from the neutral position. In spite of the usefulness and applicability, the techniques have some problems: 1) The existing observational techniques lack the consistency in the class limits of the motion categories in each body segment; 2) Most of them do not provide the post-analysis criteria needed to judge whether or not any posture is acceptable in view point of the postural load; and 3) They can not precisely evaluate the postural load for a given posture because the external loads and dynamic factors including acceleration, moment and force were not taken into consideration.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.230-233
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• 1993

This paper described a relationship between motion speed and working accuracy of industrial articulated robot arms. Working accuracy of the robot arm deteriorates at high speed operation caused by a nonlinear transformation of the kinematics and the time delay of the robot arm dynamic. The deterioration of the following trajectory was expressed as a linear function of the squares of the robot arm motion speed, depending upon a posture of the robot arm and division interval of the objective trajectory.

• Journal of the Korean Society of Safety
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• v.28 no.2
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• pp.73-77
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• 2013

Leisure activities alter overland tourism into marine tourism according to a rise in national income. It is expected that the leisure boat with period of introduction in marine tourism will be developed rapidly. It needs to unite with marine technology, optimized layout design, interior design and so on in order to build a yacht of high quality. Because optimized layout design and interior design technique increase the added value of the yacht, it needs to be convergence technology between Ergonomics, Sensibility Ergonomics, and design technique. In this study, we analyzed traffic line of crews in a sailing yacht and assessed working posture using OWAS, RULA and REBA tools. Also we suggested tips of Ergonomic design in the sailing yacht.

• International Journal of Safety
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• v.7 no.1
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• pp.35-38
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• 2008

The purpose of this study is to extract typical body shape of Korean VDT workers based on the three-dimensional Korean shape data and recommendation supported by Korea Occupational Safety & Health Agency during VDT task. Desirable desk heights and chair heights for the selection of the VDT working posture is proposed by analyzing moment, compression and joint shear for lumbar and spine of Korean adult(male and female). The desirable heights for desk and chair can be selected by the least load method during VDT tasks. In the current work the figures of Korean 50th percentile offered by CATIA-HUMAN are used as the average body type of the grown-ups and this research is accomplished with the recommended size of all working attitude such as the height of a monitor except for the height of desk and chair and the degree of watching the monitor.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.437-442
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• 2012

The current research examines the aching part and the muscle activity that happens during scaling practice subject to 20 dental hygienic students and therefore propose a basic data according to the working attitude of the Dental Hygienist. During the scaling we used the free EMG (BTS Inc., Milan, Italy) to measure the muscle activity, and in order to check the musculoskeletal pain area we used the Nordic-style questionnaire, and the measured research results are as following: At the moment of scaling according to posture the occurrence of the pain showed no difference among the groups elbow, back, leg, knee, ankle/foot but in the neck, shoulder, wrist/hand, waist showed a high difference in the degree of pain according to posture. Results from measuring the muscular activity according to posture, in the group that had a good posture, the trapezius and brachial muscles showed a change according to time, and in the group that had a bad posture a high muscle activity was shown in larynx, trapezius and brachial muscles. In the muscle activity, the changing aspect between the two parts, the group that fulfilled a scaling in a good posture showed a low muscle activity, but in the group that fulfilled the scaling in a bad posture the muscle activity increased excessively. Therefore we examined that when fulfilling a scaling maintaining a bad posture can help in using more effectively the activity of the muscle, in the future I think there is a need to raise the office efficiency by subjecting to dental hyginiest that are in the clinics and performing experiments.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.3
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• pp.415-427
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• 1993

The purpose of this study was to evaluate the thermoregulatory responses to postures under different environmental conditions and to obtain the basal information for standard clothing weight, indoor climates, and working condition. Two adult female (22.5yrs, 46kg) were participated in this study. The experimental conditions were divided into three groups ; 1) comfort($27{\pm}1^{\circ}C$, $60{\pm}10%$), 2) hot($34{\pm}1^{\circ}C$, $60{\pm}10%$), and 3) cold($21{\pm}1^{\circ}C$, $50{\pm}10%$) condition. The postures performed were as follows; standing, sitting on the chair, sitting on the floor, and supine on the floor. At each condition, subjective sensations, 12 points skin temperature, rectal temperature, total and local sweat rate, pulse rates, blood pressure, skin blood flow rate were measured. The results were as follows : 1. Rectal temperature was high significant among groups in order of supine, sitting on the floor, sitting on the chair, standing posture(p<0.01). 2. Skin temperature was high in part of contact with the surface of the floor or wall and the effect of posture was greater in peripheral temperature than torso temperature. Sitting on the chair and sitting on the floor posture showed higher peripheral temperature than standing and supine posture. And peripheral temperature was lower in supine posture than any other postures. 3. Total and local sweat rate were decreased in order of standing, sitting on the chair, sitting on the floor, supine posture. 4. Pulse rate and disastolic blood pressure were higher in standing posture than supine posture, and there was significant difference between two postures(p<0.001). 5. Blood flow rate of thigh was high in sitting on the chair and sitting on the floor posture and low in standing posture. Blood flow rate of leg was low in standing posture significantly(p<0.01). 6. In comfort and hot condition, temperature sensation and comfort sensation were higher in standing posture and lower in supine posture than any other postures. In cold condition, temperature sensation was lower and comfort sensation was higher in standing and supine posture than any other postures. And supine posture was appeared positive in hot condition and negative in cold condition. From this study, we confirmed the effects of posture on human thermoregulatory responses. Results indicate that even under same conditions and clothing weight, the insulation of clothing will be different to postures.

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.127-132
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• 2005

The purpose of this study is to compare representative posture classification schemes of OWAS, RULA and REBA in terms of correctness for postural load. The comparison was based on the evaluation results by the three methods for 224 working postures sampled from steel, electronics, automotive, and chemical industries. The results showed that OWAS and REBA generally underestimated postural stress than RULA irrespective of industry type, work performed and whether or not leg posture is balanced. While about $71\%\;and\;73\%$ of the 224 posture were evaluated with the action category/level 1 or 2 by OWAS and REBA respectively, about $60\%$ of the postures were classified into the action level of 3 or 4 by RULA. The coincidence rate of postural stress category between OWAS and RULA was just $33.5\%$, while the rate between RULA and REBA was $46.0\%$. It is concluded from the findings of this study and the previous research that compared to OWAS and REBA, RULA more precisely evaluates postural stress.