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

• The Journal of Korean Physical Therapy
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• 제11권2호
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• pp.1-4
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• 1999

The purpose of this study was to analyze the changes of the muscle strength and length according to the changes of evaluation postures. Subjects of this study were 13 male and 13 female students. 6 evaluation postures were selected for this study(K90H90, K90H45, K90H0, K70H90, K70H45, K70H0 ; K90=knee $90^{\circ}$ flexion, K70=knee $70^{\circ}$ flexion, H90=hip $90^{\circ}$ fleion, H45=hip $45\circ}$ flexion. H0=hip $0^{\circ}$ ). The peak torque and hamstring muscle length(from fibula head to ischial tuberosity) were measured at each postures. The peak torque level was evaluated by make use of the KIN-COM. The results were as follows : 1. The peak torque in male was significantly increased with changes of hip flexion angle but not in female(($90^{\circ}\;>\;45^{\circ}\;>0^{\circ}$). 2. The hamstring length and peat torque in male and female was significantly changed according to the alteration of evaluation postures.

• 한국안전학회지
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• 제12권4호
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• pp.209-213
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• 1997

Manual lifting techniques are commonly defined in terms of the postures adopted at the start of the lift. Quantitative definition is problematic, however, because the absolute joint angles adopted to lift an object are influenced by task parameters, such as the initial height of the load. The main objective of this study is to investigate the grip strength of the both hands at the initial lifting points. The survey is conducted by measuring the compression force, anthropometric data and grip strength at the lifting postures for the subjects(n=50) who is assigned to their job as usual. The experiment is peformed at the four lifting postures which involving the combination of two horizontal factors(H1 : 35 cm, H2 : 55 cm) and two vertical factors(V1 : 20~80 cm, V2 : 47~102 cm). The analysis result of lifting posture indicated that each H1-V1, H2-V1 combinations are about 60$^{\circ}$ and each H1-V2, H2-V2 combinations are about $30^{\circ}$. There are significant differences on grip strength between $60^{\circ}$ and $30^{\circ}$ stooped posture. The results of this study can be provided a method defining lifting postures at the minimum grip strength. Also, it is eliminated a hazard of the injuries which are cumulative trauma disorders(CTDs) and back pain, increased a productivity and improved a welfare of workers.

• International journal of advanced smart convergence
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• 제7권3호
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• pp.110-118
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• 2018

This study aimed to examine the postures and behaviors of high school sophomores in Gyeongnam Province in daily life and the relations between back pain and sitting postures, and to identify undesirable behaviors and postures in daily life, and the following conclusions were obtained. The relation between back pain and cupping the chin in one of the two hands in rotation or sitting with the legs crossed or sitting on a chair with the back and hip not leaning against the backrest was statistically significant (p<0.05). The results above indicated that high school sophomores in South Korea spend most of the day sitting on a chair in school and that undesirable behaviors using one side of the body, such as cupping the chin in one of the two hands in rotation or sitting with the legs crossed, cause back pain. In addition, those who sit on a chair with the back and hip leaning against the backrest experienced less back pain than those who did not, and exercises after school were found to be helpful to prevent back pain.

• 대한인간공학회지
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• 제22권1호
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• pp.43-56
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• 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.

• 대한물리의학회지
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• 제14권1호
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• pp.43-51
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• 2019

PURPOSE: To prevent secondary complications from decreased pulmonary functions and promote neurological recovery, identification of respiratory capacity change patterns depending on different postures of stroke patients and investigation of their properties are needed for active rehabilitation. Therefore, this study was conducted to investigate the changes in vital capacity in response to different positions and to implement the results as clinical data. METHODS: A respiratory function test was administered to 52 patients with stroke in the sitting, supine, paretic side lying, and non-paretic side lying positions. Pulmonary function indexes used for comparison were forced vital capacity (FVC), forced expiratory volume at 1 second (FEV1), forced expiratory flow 25-75% (FEF 25-75%), and maximum voluntary ventilation (MVV). One-way repeated ANOVA was used for analysis, and post hoc analysis was conducted using least significant difference (LSD). RESULTS: All pulmonary function indexes were measured in the order of sitting, paretic side lying, supine, and non-paretic side lying positions. Excluding the FEF25-75% and MVV of the supine compared with the paretic side lying position, all other pulmonary function indexes differed significantly (p<.05). CONCLUSION: There are differences in pulmonary function indexes depending on different postures of stroke patients, and the study showed that the non-paretic side lying position yielded the greatest effect on lung ventilation mechanisms. Based on these results, appropriate postures need to be considered during physical therapy interventions for stroke patients.

• PNF and Movement
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• 제19권2호
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• pp.243-250
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• 2021

Purpose: The purpose of this study was to observe office workers' postural behaviors during computer work to identify the risk factors for head and thorax postural behaviors. Methods: The participants included 57 office workers who worked longer than 20 hours on a computer. Postural behaviors during computer work were measured using 3-D wearable motion sensors on the forehead and sternum. A multivariate linear regression model evaluated the association between various risk factors (neck pain, demographics, and environmental factors) and non-head and thorax postural behaviors. Results: The participants maintained their head and thorax in neutral postures (defined as 10° extension~10° flexion and 5° extension~10° flexion, respectively) for 24.7% and 39.3% of the total recorded time. Those who reported neck pain at the measurement of postural behaviors showed less time spent in thorax postures. Current neck pain, high desk height, and the distance between the keyboard and the edge of the desk (cm) were found to be related to less time spent in a neutral thorax posture. Conclusion: Office environment factors and current neck pain might affect workers' thorax postures, which might also determine the orientation of head postures during computer work.

• 자동차안전학회지
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• 제15권4호
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• pp.95-101
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• 2023

As the popularization of autonomous vehicles is anticipated, it is expected that the variety of passenger postures will diversify. However, the current vehicle safety system is expected to be inadequate for accommodating these diverse passenger postures, particularly in reclined positions where severe injuries have been reported in frontal collisions. Therefore, it is necessary to investigate the biomechanical responses and tolerances of occupants in reclined postures. In this study, the behavior and injuries of a Hybrid-III dummy model in a reclined position are analyzed through frontal collision sled simulations equipped with the semi-rigid seat provided by the previous study, three-point safety belt with pretensioner and load limiter, and airbag models. The results are evaluated by comparing thouse reponses with post-mortem human surrogate (PMHS) data, and the findings are expected to be applicable to the basic design of a new restraint system suitable for various postures in autonomous vehicles.

• 대한인간공학회지
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• 제24권3호
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• pp.11-27
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• 2005

The objectives of this study are to analyze representative wrist postures while using hand tools and parts at general assembly processes, to evaluate perceived discomfort on the wrist when external loads are present, and to suggest an evaluation and prediction model of perceived discomfort. Sixteen subjects participated in an experiment to appraise perceived discomfort. Three types of the wrist postures with five levels of non-neutralities were analyzed when five levels of external load were applied to each posture. The ANOVA results showed that the perceived discomfort of wrist postures was significantly affected by both the wrist posture and external load (p$<$0.001). It was also shown that some of the interactions between external loads and the wrist postures(Flexion/$Extension^*$Load, Flexion/$Extension^*$supination/pronation, ulnar/radial $deviation^*$supination/pronation) were significant(p$<$0.001). The result implies that a new posture classification scheme for workload assessment methods may be needed to reflect such effects of external load and wrist posture. A regression model of perceived discomfort was developed with respect to wrist posture and external load from the experimental data. A subsequent experiment revealed that the correlation coefficient between the predicted values of perceived discomfort from the model and the actual values obtained from the experiment was about 0.98. It is expected that the results help to properly estimate the body stress resulting from worker's postures and external loads and can be used as a valuable design guideline to analyze potential hazard of musculoskeletal diseases in industry.

• 한국직업건강간호학회지
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• 제12권1호
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• pp.31-38
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• 2003

This study is an attempt to analyze the physical load by the type of the nursing tasks at the neurosurgical ICU nurses through the quantitative analysis of the working postures by the type of the nursing tasks with the OWAS(Ovako Working Postures Analysis System). Data collection was conducted through the video recording of the 13 nurses working at the neurosurgical ICU. For the analysis of the work postures by the type of the nursing tasks, and were interviewed regarding the subjective degree of the difficulties with the work postures related to the tasks. Collected data was analyzed through the WinOWAS program. The results were as follows : AC3 or AC4 tasks among the 18 nursing tasks types are "occupied bed making and change of the patient gown", "back massage", "suction", "elimination management", "change of position", "adjustment of bed", "helping the patient to move","measurement of CVP"and "measurement of urine volume". It appears that these tasks are harmful to the musculoskeletal system and the improvement or change of the work is required. The results stated above indicate that improper working postures during the nursing tasks influence the musculoskeletal system. Therefore, making use of assistant devices for the improvement of the working environment at the nursing tasks, based on human technological diagnoses, is required regarding the duty types with massive work pressure known to be harmful to the musculoskeletal system among those performed by the nurses. And there is a need of the education about the employment and maintenance of the vocational back pain prevention.