• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1994년도 춘계공동학술대회논문집; 창원대학교; 08월 09일 Apr. 1994
• /
• pp.561-568
• /
• 1994

A man model can be used as an effective tool to design ergonomically sound products and workplaces, and subsequently evaluate them properly. For a man model to be truly useful, it must be integrated with a posture prediction model which should be capable of representing the human arm reach posture in the context of equipments and workspaces. Since the human movement possesses redundant degrees of freedom, accurate representation or prediction of human movement was known to be a difficult problem. To solve this redundancy problem, a psychophysical cost function was suggested in this study which defines a cost value for each joint movement angle. The psychophysical cost function developed integrates the psychophysical discomfort of joints and the joint range availability concept which has been used for redundant arm manipulation in robotics to predict the arm reach posture. To properly predict an arm reach posture, an arm reach posture prediction model was then developed in which a posture configuration that provides the minimum total cost is chosen. The predictivity of the psychophysical cost function was compared with that of the biomechanical cost function which is based on the minimization of joint torque. Here, the human body is regarded as a two-dimensional multi-link system which consists of four links ; trunk, upper arm, lower arm and hand. Real reach postures were photographed from the subjects and were compared to the postures predicted by the model. Results showed that the postures predicted by the psychophysical cost function closely simulated human reach postures and the predictivity was more accurate than that by the biomechanical cost function.

• 한국전문물리치료학회지
• /
• 제27권4호
• /
• pp.278-285
• /
• 2020

Background: Individuals with forward head posture (FHP) have neck pain. To correct the FHP, a posture correction band is commonly used. However, we do not know the posture correction band influenced the pulmonary function in individuals with FHP. Objects: This study aimed to elucidate the effects of the posture correction band on the pulmonary function in young adults with neck pain and FHP and to monitor how the pulmonary function changed over time. Methods: Twenty subjects with chronic neck pain and forward head posture were recruited. Subjects performed pulmonary function test four times: before, immediately, and 2 hours after wearing the postural band, and immediately after undressing the postural band. Vital capacity (VC), forced vital capacity (FVC), peak expiratory flow (PEF), and forced expiratory volume at one second (FEV1) were measured. The modified Borg dyspnea scale was used to measure each subject's responses to the posture correction band. The mixed-effect linear regression was used to the effect of the posture correction band over time. Results: There were no significant differences in VC, FVC, PEF, FEV1 values over time (p > 0.05), although all values slightly decreased after applying posture correction band. However, the score of the modified Borg scale significantly changed after wearing the postural bands (p < 0.05), indicating the subject felt discomfort with posture correction band during breathing. Conclusion: Because the posture correction band did not change the pulmonary function over time, but it induces psychological discomforts during breathing in people with FHP. Therefore, this posture correction band can be used for FHP realignment after discussion with the subjects.

• 대한인간공학회지
• /
• 제24권2호
• /
• pp.9-15
• /
• 2005

The purpose of this study is to quantitatively investigate perceived discomfort of complex shoulder postures with external loads and to propose a preliminary evaluation scheme of shoulder postures. Twelve healthy male adults participated in an experiment to rate their perceived discomfort of shoulder postures. The independent variables were shoulder flexion angle(45, 90 and 150$^{\circ}$), adduction/abduction angle(-30, -10, 0, 30 and 60$^{\circ}$), and external load(0, 1.5 and 3.0kg). The results revealed that the flexion angle, external load and their interaction significantly affected the perceived discomfort(p$<$0.05) but the effect of adduction/abduction angle on the discomfort was not significant(p$>$0.05). The effect of external load was much larger than that of any other factor with explaining about 81% of the total variation of discomfort scores. Based on the experimental results a preliminary scheme was presented to evaluate the stress of shoulder postures with external loads.

• 한국생활과학회지
• /
• 제19권4호
• /
• pp.655-665
• /
• 2010

This study analyzed the effects of skinny jean on women's health by questionnaire survey and measuring the pressure experienced under the clothing and participants' subjective view of the pressure level. The average size women in their 20s' waists is 26 inches and so three pairs of jeans were prepared and worn by 4 female participants. A survey was conducted to investigate how often participants wear skinny jeans and whether they had had any feelings of discomfort as a result of this. Participants responded that they hadexperienced middle to high levels of discomfort due to the high pressure inside skinny jeans. For the maximum value of clothing pressures, jean f2 at the part of buttocks showed $48.7gf/cm^2$. The pressure inside the clothing was found to be highest around the buttocks followed by the knees and finally the belly. The mean values of 7 measuring parts are different according to the jean type; f3 $20.8gf/cm^2$ > f2 $16.4gf/cm^2$ > f1 $15.5gf/cm^2$, which is corresponding to the order of pressure sensation, but not corresponding to the order of ease amount of clothing pattern: f2 > f3 > f1. Mean pressure values were also measured according to the body posture: they were found to by highest when sitting on a chair (21.3gf/$cm^2$), second highest when sitting on the floor ($19.2gf/cm^2$) and lowest when standing ($15.0gf/cm^2$). This is not always same to the order of participants subjective perceptions of the pressure, which is, they estimated pressure to be highest when sitting on the floor followed by sitting on a chair and lowest in a standing position.

• 감성과학
• /
• 제4권1호
• /
• pp.53-60
• /
• 2001

As a part of HMS(Human-Machine System), the car is very important thing in common life. It is also a significant part to study on the controllers of car that is intentively related with all sensibilities during driving. There are lots of controllers on seating buck of the car. However, there are few study on the sensibility analysis of them. Most of all, the foot controller could be easily overlooked because it could be invisible. This study was based on relationship that the controllers fitted to the driving posture in the drivers' sensibility difference of two transmission modes, automatic and manual transmission. The results show the driver's preference driving posture and sensibility in two kinds of transmission cars. Consequently, it should be designed the seating buck for two different types respectively to be taken comfort driving posture and improve the safety for drivers. Also, it could reduce the fatigue and discomfort in the task of driving. The design of the controllers strongly effects on the drivers' response time. hereby this study was accessed to the sensibility of Korean with analyzing the relationship, quantitative data, and sensibility difference between two kinds of transmission cars.

• 한국소음진동공학회논문집
• /
• 제20권12호
• /
• pp.1121-1127
• /
• 2010

Human characteristic responding to idle vibration on passenger vehicle was studied to find if affected by seating posture of passenger. When twelve male subjects are exposed to moderate vertical vibration of 0.224 $m/s^2$ r.m.s. at frequency range from 3 Hz to 40 Hz, it was found that seating posture significantly affects to biodynamical characteristics, apparent mass and apparent eccentric mass, at most range of idle vibration frequency(20~40 Hz). The supported thigh contact on rigid seat showed bigger values in the two biodynamical characteristics than the average thigh contact. The bigger apparent mass and apparent eccentric mass in the seating posture of the supported thigh contact can be assumed more strengthened muscle at the frequency range.

• 융합신호처리학회논문지
• /
• 제23권3호
• /
• pp.115-122
• /
• 2022

몇 년 전 코로나가 발병하면서 화상 회의, 전자 문서 작업이 많아지게 되었고 이 때문에 현대인들의 하루 일과 중에서 컴퓨터 작업을 하는 비중이 증가하고 있다. 하지만 오랜 시간 동안 잘못된 자세로 컴퓨터 작업을 하는 사람들이 많아지게 되면서 시력 저하, 거북목증후군 환자들이 늘고 있다. 최근까지도 자세 교정을 위한 연구들이 많이 발표되고 있지만 대부분은 사용자가 장비를 착용하여 자세 교정을 해야 하므로 사용자가 불편함을 겪을 수 있다는 한계가 있다. 본 논문에서는 초음파 센서 장치를 이용하여 컴퓨터 모니터와 사람 사이의 최소 거리 접근을 방지하기 위한 자세 교정 센서 시스템을 제안한다. 그리고 이때 최소 거리 시 울리는 경고 알람 중 오류 알람을 최소화하는 알고리즘도 함께 제안한다. 이는 초음파 센서 장치를 이용하기 때문에 몸에 기기를 부착하지 않고도 자세 교정을 할 수 있으며 사용자의 불편함을 해소할 수 있다는 장점이 있다. 또한, 실험 결과에서 거리 측정 시 발생한 잡음을 제거하여 오류 알람을 줄임으로써 정확도를 높일 수 있음을 보였다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2009년도 추계학술대회 논문집
• /
• pp.584-590
• /
• 2009

Since driving include compilcated actions that require a variety of abillity and cause extrme concentration or strain, divers tend to feel tired easiy. However, divers can't recognize fatigue degree by himself and accordingly the methods to measure quantitative fatigue degree exactly is quite difficult to be secured. In this study, the most efficient driving posture was suggested based on the analysis of quantitative muscular strength and fatigue degree according to posture. The driver whom we experimented included 9 commercial bus drivers. We also analyzed quantitative legs' muscular strength according te operating each pedal, left and right then we analyzed muscular strength and muscular fatigue degree according to driving pattern while driving commercial buses. And then we suggested the most efficient driving posture.

• 대한산업공학회지
• /
• 제31권4호
• /
• pp.289-296
• /
• 2005

This study aims to measure maximum holding times(MHTs) of symmetric and asymmetric whole body postures, and to compare three representative observational methods including OWAS, RULA, REBA, based on the MHTs. An experiment was conducted for obtaining the MHTs, in which hand position was used as experimental variable, and the MHT and subjective discomfort rating as dependent variables. The hand position was defined by the percentage of the shoulder height(%SH), the percentage of the arm reach(%AR) and rotation angle(R). The results showed that three independent variables of %SH, %AR and R significantly affected on the MHTs at ${\alpha}$=0.01, and that the MHTs were negatively linearly related to the discomfort scores of Borg CR10. It was also revealed that OWAS and REBA were less sensitive to postural stress than RULA. In addition, OWAS and REBA underestimated postural load of given postures compared to RULA. Therefore, it is recommended that among the three observational methods investigated in this study, RULA be used for a more precise evaluation of postural load.

• 대한인간공학회지
• /
• 제22권1호
• /
• pp.43-56
• /
• 2003

Observational methods such as OWAS, RULA, and REBA have been widely used to identify posture-related risks of musculoskeletal disorders in industry, since they are useful and efficient in evaluating postural stresses. However. there are few studies comparing the methods and providing guidelines for selecting and using the methods. They have been developed based on different backgrounds and with different application areas. Each method has its own characteristics. which must be considered in selecting and using them. In this study. 17 male subjects evaluated 42 different working postures that frequently assumed in the automobile assembly line using a psychophysical method. The postures were then evaluated by different observational methods. The results of the observational methods were compared with psychophysically evaluated stresses. The observational methods resulted in different values of stresses for certain postures. For some postures showing high values of perceived discomfort. the observational methods showed different values of stresses. These results showed that the observational methods should be used differently according to application area and they have some weak points to be improved.