• 산업경영시스템학회지
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• 제18권36호
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• pp.1-11
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• 1995

Manual lifting, as a part of manual materials handling activities, is recognized by authorities in the fields of occupational health and safety as a major hazards to industrial workers. In order to minimize the injuries caused by manual material handling activities as well as maximize job productivity, it is important to determine the maximum weights. This paper presents the optimal combination of membership functions according to the high lifting frequency and determines the safe maximum acceptable weights in manual lifting activities through the actual experiment.

• Industrial Engineering and Management Systems
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• 제7권1호
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• pp.90-98
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• 2008

This research selects the lifting task to be the main subject. Four experiments were designed to measure which among lifting postures, lifting heights, waist-belt, and breathing control significantly influences intra-abdominal pressure (Gallagher, 1991; Lavender, Andersson and Natarajan, 1999). The experimental results were taken to be the recommendations of the manual materials handling work design. The research findings reveal that the symmetrical stoop posture is the most significant to the intra-abdominal pressure within all lifting postures. When the lifting height is increased, the intra-abdominal pressure produced relatively goes up. Also, the combination of symmetrical stoop posture, waist-belt use, and inspiration and holding at the same time is the most efficient in carrying out lifting tasks. Simultaneously, the research discovers that for any posture, the volume of the intra-abdominal pressure is much bigger when using the waist-belt compared to when it is not used. Therefore, the waist-belt design for the lifting works might be the future research approach.

• 한국안전학회지
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• 제8권4호
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• pp.82-90
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• 1993

Manual lifting, as a part of Manual Materials Handling Activities, is recognized by authorities in the field of occupational health and safety as a major hazard to industrial workers. The most important problem in applying fuzzy model of manual materials lifting is the decision of membership functions on each approaches. : Biomechanical, Physiological, Psychophysical. The primary objectives of this paper suggests to process deciding the most acceptable membership functions for establishing permissible weights on manual lifting activities using fuzzy sets.

• 한국안전학회지
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• 제14권3호
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• pp.174-180
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• 1999

The objective of this study was to investigate the effects of carrying postures and weight of load carried one time on a worker when carrying heavy loads. Six male students participated in this study to perform a manual materials carrying task as subjects. To make comparison of work loads with physical work capacity, maximal oxygen uptake measurement tests were performed with submaximal test. The average oxygen consumption for the tasks of this study was 27.59~31.93% $VO_2$max. The results showed that the weight of load carried one time affects on working heart rate and oxygen consumption($VO_2$). It was found that the workload was significantly lower when handling a 20kg load at a frequency rate of 3times/min than when handling a 40kg load at a frequency rate of 1.5 times/min. There was no difference between carrying postures. It is concluded from the results of this study that the workload can be reduced by controlling conditions of a manual materials handling task.

• 한국컴퓨터정보학회논문지
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• 제19권3호
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• pp.155-161
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• 2014

본 연구의 목적은 보병용 휴대 배낭 설계를 위하여 인체공학적인 물자취급 중량을 검토하여 휴대 및 이동성능에 기초한 한계하중을 분석하는데있다. 제품설계시 인체공학적 설계가이드라인과 운용현황을 조사분석하여 효율적인 운용성능을 위한 기초자료로 제공하고자 한다. 본 연구에서는 인력물자취급시 역사적 관점에서 생리학적 연구방법, 생체역학적 연구방법, 인체심리학적 연구방법들을 검토하여 보병용 휴대배낭의 휴대성 및 이동성을 분석하였다. 휴대성과 이동성 간의 관계를 분석한 결과, 단거리의 짧은 기동거리에서는 생체역학적 기준치를, 1-2시간의 중간인 이동에서는 인체심리학적 기준치를, 4시간 혹은 그 이상의 장거리에서는 생리학적 기준치를 적용하여 각각의 가이드라인들을 상호 절충하는 것이 필요한 것으로 판단된다. 본 연구에서는 보병의 물자취급시 4가지 연구방법을 제안하였다. 이러한 기존의 설계 가이드라인을 분석한 결과, 병사의 인체사이즈 측면에서는 5%tile의 경우 -091kg으로 여유중량이 부족하지만, 95%tile에서는 34.17kg까지 여유중량이 발생하는 것으로 판단된다. 이러한 연구결과는 물자취급시 편하고, 효율적인 운용성능을 창출하기 위해서 휴대중량과 이동거리에 따라 여유중량을 관리해야 할 것으로 판단된다.

• 대한인간공학회지
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• 제26권2호
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• pp.35-44
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• 2007

Work-related musculoskeletal disorders (WMSDs) are a major problem in industries in which manual materials handling is performed by workers. To prevent these WMSDs, it is necessary to understand the muscular strength capability and use this knowledge to design job and selection and assignment of workers. Even though two-hands lifting activity of manual materials handling tasks are prevalent at the industrial site, many manual materials handling tasks which require the worker to perform one-hand lifting are also very common at the industrial site and forestry and farming. However, a few researches have been done for one-hand lifting activity of manual materials handling tasks. The objective of this study is to compare one-hand and two-hands lifting strength in terms of static and dynamic strength of the lifting activity for the ranging from the height of knuckle to elbow. It is shown in this study that the isometric lifting strength of one-hand is ranging from 54.7 to 63.3% of the one of two-hands. However, it is found that there is no significant difference between a person's isometric lifting strength for left-hand and right-hand. It is also shown that there is no significant difference between the peak force under the dynamic sub-maximal loading with one-hand and two-hands lifting activity. Similar results were obtained for the peak acceleration and peak velocity under the dynamic sub-maximal loading with one-hand and two-hands lifting activity. Isometric lifting strength at the height of knuckle was ranging from 2 to 3 times of the dynamic peak force during sub-maximal lifting. It is concluded that the dynamic peak forces under the sub-maximal loading are not highly correlated with the isometric lifting strength in similar postures.

• 대한인간공학회지
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• 제26권4호
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• pp.49-56
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• 2007

Handles on objects are very important to increase the safety and efficiency of manual handling of people who use them. In this study, four different prototype cartons combined with auxiliary handles were designed to determine the optimal handle position of cartons through the evaluation of user preferences. Twenty male students are participated in the experiment. Likert-5 point summated rating method was applied to evaluate the user preferences for provided handles of the carton among upper, middle, and lower position under the four different sizes and materials handling conditions(carrying positions). The results show that the subjects preferred upper part of the handle on the small cartons regardless of the carrying positions while upper and middle parts of the handle on the big cartons for handling above the waist height were preferred. An optimal handle position depending on the different sizes of carton and the different carrying positions were recommended based on the results of evaluation. It is thus recommended that the cartons provide handles on its relevant position depending on the size and materials handling condition to reduce the musculoskeletal stress and in turn to increase the user satisfaction.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.144-144
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• 2000

Air balance hoists are widely used in handling of heavy materials in industry. Currently used air balance hoists adopt manual switches for vertical motion, thus the operator has a difficulty in operating of the switches and handling of material simultaneously. To overcome this difficulty, this study develops a weightless air-balance-hoist system using compressed air. This system memorizes the weight of material in terms of pneumatic pressure with a pneumatic circuit. Such memory of the material weight is used for achieving weightless handling of materials. Through a series of experiments, handling forces and the response of the system for various material weights are analyzed. The results show that the developed system can be used for weightless handling o( heavy materials.

• 대한인간공학회지
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• 제23권4호
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• pp.1-8
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• 2004

The objective of this study is to identify the effects of material position and physical fatigue on postural stability. Ten male subjects participated in this study. After bicycling exercises, their centers of pressure (COPs) were measured under four material handling positions and four excercise levels. The measured COPs were then utilized to calculate postural sway length in each experimental condition. Subjects' postural stability was quantified using the sway length. Results showed that the effect of different material handling position was significant on the postural sway length in both the posterior-anterior axis and the medio-lateral axis. Results also showed that the postural sway length was increased as physical fatigue accumulated, significantly in subject's posterior-anterior axis. The results imply that bearing a material on the back or front with both hands appeared to cause least sway length and instability.

• 한국포장학회지
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• 제11권1호
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• pp.17-24
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• 2005

During handling unitized products, they are subjected to a variety environmental hazards. Shock and vibration hazards are generally considered the most damaging of the environmental hazards on a product, and it may encounter while passing through the distribution environment. A major cause of shock damage to products is drops during manual handling. The increasing use of unitization on pallets has been resulted in a reduction in the manual handling of products and with it a reduction in the shock hazards. This has caused and increasing interest in research focused on vibration caused damage. the use of pallets as a base for unitizing loads, aids in the mechanical handling, transportation and storage of products. Besides aiding in the handling, transportation and storage of products, a pallet also acts on and interface between the packaged goods and the distribution environment. The determination of the impact deformation of the cushioning materials such as tray cup (polymeric foam) and corrugated fiberboard pad must be carried out to design the proper packaging system providing adequate protection for the fruit, and to understand the complex interaction between the components of fruit when they relate to expected transportation vibration inputs. In this study, the theoretical analysis of impact deformation for cushioning materials by dynamic vibration. The impact deformations of SW and DW corrugated fiberboard pad in acceleration amplitudes of 0.25 G-rms and 0.5 G-rms that were usually generated in transport vehicles during distribution environments were very small compare with the thickness of corrugated fiberboard pad. The maximum of vibration acceleration level of tray cup by vibration impact was about 3.2 G-rms. The theoretical allowable acceleration (G-factor) of the pear was 0.7102 G-rms, and the maximum dynamic deformation estimated within G-factor was about 1 mm.