• 산업경영시스템학회지
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• 제23권56호
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• pp.93-102
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• 2000

Today, the number of automated machine has rapidly increased in industrial workplaces. Nevertheless, workers are often required to handle materials manually. Technical information for using the revised NIOSH lifting equation to evaluate a variety of two - handed Manual Material Handling (MMH) tasks was investigated. The NIOSH suggested the Lifting Index that provides a relative estimate of the level of physical stress associated with a particular manual lifting task. To measure operator's workload in lifting task, Lifting Index Simulator(LIS) was developed based upon the revised NIOSH lifting equation in this study. The purpose of this study was to develop LIS and use the NIOSH lifting equation in our workplace.

• 한국CDE학회논문집
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• 제15권1호
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• pp.1-10
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• 2010

Recently, a shipyard is making every effort to efficiently manage equipments of resources such as a gantry crane, transporter, and so on. So far block lifting scheduling of a gantry crane has been manually performed by a manager of the shipyard, and thus it took much time to get scheduling results and moreover the quality of them was not optimal. To improve this, a block lifting scheduling system of the gantry crane using optimization techniques was developed in this study. First, a block lifting scheduling problem was mathematically formulated as a multi-objective optimization problem, considering the minimization of travel distance at an idle state and wire replacement during block lifting. Then, to solve the problem, a meta-heuristic optimization algorithm based on the genetic algorithm was proposed. To evaluate the efficiency and applicability of the developed system, it was applied to an actual block lifting scheduling problem of the shipyard. The result shows that blocks can be efficiently lifted by the gantry crane using the developed system, compared to manual scheduling by a manager.

• 대한안전경영과학회지
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• 제2권2호
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• pp.11-20
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• 2000

Today, technologies and automation have been accelerated up in the industrial workplace. Nevertheless, many systems still require humans to handle materials manually. The Low Back Pain (LBP) is one of modern human being's most common and complex ailments. Many risk factors with the onset of LBP have been identified, however, lifting out of Manual Material Handling(MMH) was the most important factor to the LBP. The Virtual Reality(VR) is used in a variety of ways and often in a confusion and misleading manner. In order to solve the prevention of the LBP, a lifting box was translated in the Virtual Environment(VE). As simulating under the VE, optimal lifting works could be constructed. The purpose of this study is to reduce the chronical low back pain for the manual material handlers.

• Journal of Welding and Joining
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• 제25권6호
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• pp.44-52
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• 2007

A welding process of a lifting lug for lifting heavy objects is one of the important welding processes directly related to the safety in shipbuilding. Welding a lifting lug is done in the manually and takes about forty minutes. Working environment for the lifting lug welding is very poor due to an radiant heat and a harmful fume. The purpose of this study is to develop methods of multi-pass welding using the lifting lug welding robot system. This study shows robot welding methods to achieve proper corner, straight and connection welding and an effectiveness of application.

• 한국산업보건학회지
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• 제31권2호
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• pp.156-172
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• 2021

Objectives: To investigate the trends of industrial injuries among long-term health care workers in Korea Methods: T7866 injuries were selected from the total industrial injuries approved by the Industrial Accident Compensation Insurance Act(Occupational Safety and Health Act) among long-term health care workers between 2007 and 2016 in Korea. We analyzied the trends of industrial injuries according to work process, occurrence type, and causes. Results: The industrial injuries among long-term health care workers increased since 2012. The mostly occurred area for industrial injuries were low back areas, which is related that the most serious industrial injuries occurred when the one long-term healthcare worker lift manually the recipient, from bed(ondol, Korean floor heating system) to a wheelchair, bed to bath bed, and wheelchair to bath chair. In addition to this, lack of workforce, increased work intensity due to overwork contributed the increasing of occupational injury. Conclusions: This study suggests that the main causes of industrial injuries were Lack of facilities and equipment for small private long-term care institutions, The physical load that goes into lifting the recipient directly, work intensity such as excessive workload and increased work speed. We suggest that the social publicization of long-term care service for the elderly, avoiding ways to lift recipients directly, introducing lifting machines as well as improving working methods, and reducing the workload of caregivers are required.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.648-655
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• 1993

The hydraulic coconut dehusking machine consists of three main parts ie. The frame , the power unit including the hydraulic accessories, the lifting and dehusking mechanisms. Two sets of the hydraulic coconut dehusking machine were developed . their hydraulic and electrical control circuits were connected in series to enable them operating contemporaneously. Two operators are required to operate the machine. Each of them put a coconut on the lifting mechanism in order to start the working cycle automatically. As a result, the nut are immediately pushed up and seized by the holding teeth under the supplement of the hydraulic reducing circuit. After that the dehusking mechanism started operating via the sequence circuit. At the end of the cycle, both mechanisms return to their original positions. Some remaining fibrous is taken out manually from the nut subsequently . The continuous dehusking speed was found to be 22.2 seconds per 2 coconuts.

• 한국강구조학회 논문집
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• 제21권4호
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• pp.413-420
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• 2009

일반적으로 대형 지붕구조나 초대형 보와 같은 대형 구조물을 양중하는 방법은 유압잭이 이용된다. 또한, 양중시 안전을 위하여 CCTV를 이용하여 각 포인트에 설치된 줄자를 모니터링하여 레벨체크를 수행하고, 상대 변위가 기설정된 한계를 벗어나면 유압잭을 정지하고 상대변위를 수동으로 조정한 후에 양중을 수행하였다. 그러나, 이러한 종래의 양중 방법은 CCTV를 육안으로 확인하여 레벨을 체크하기 때문에 정확도가 높지 않았고, 실시간 계측은 현실적으로 불가능하였다. 이러한 문제를 개선하기 위하여 자동추적형 토탈스테이션, 레이저 거리계, 데이터로거, 변형도게이지 등을 이용하여 대형 구조물 양중시 적용할 수 있는 계측-평가 시스템 구축하였다. 시스템을 구현하기 위한 프로그램 작성 후 실험실에서 시연을 통해 계측-평가 데이터의 정확성 및 활용 가능성을 평가하였으며, 안정적인 데이터 취득 및 연산을 통해 적용성이 검증되었다.

• 대한인간공학회지
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• 제34권3호
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• pp.279-291
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• 2015

Objective: The purpose of the study is to evaluate appropriate weight for aged farmers in manually handling livestock feed in bags using ergonomic methods. Background: In the livestock industry in South Korea, despite the trend of aging of labor manpower, heavy items are still manually handled in many farms. In particular, among stockbreeding works, the handling of feed in bags weighing 25~30kg is reported as a cause of frequent injuries and musculoskeletal system diseases. However, studies on the standard for recommended weight allowed considering the physical characteristics of aged farmers older than 60 years with greatly decreased physical strength and muscle strength are insufficient. Method: To evaluate appropriate weight for handling of heavy livestock feed in bags, physical techniques for measuring recognized levels of physical work loads, the NLE (NIOSH lifting equation) a method that is an observation type technique, and an ergonomic modeling technique to predict compressive force imposed on L5/S1 were used. Subjects who participated in the experiment were organized into two groups of males/females with mean age exceeding 60 years, and lifting tasks were evaluated for nine weight levels. Results: Based on the results of psychophysical measurement, females showed a tendency of more drastic increases compared to males when weight was over 19kg. The results of estimation of regression models for the weight, 18.0 kg ($r^2=0.97$) and 15.3kg ($r^2=0.97$) were evaluated as stable load for males and females, respectively. In addition, both the observation type evaluation and ergonomic model evaluation showed stable loads in a range of 15~18kg. Conclusion: Given the results of the study, the weight of the feed in bags currently distributed to farms can become a cause of not only overexertion but also farm work related disasters such as musculoskeletal disorders and safety accidents. Providing livestock feed in bags weighing not more than 19kg for aged farmers is judged desirable, and managerial improvement for this matter is considered necessary. Application: The results of the present study can be utilized as useful data for institutional improvement of the weight of livestock feed in bags.

• 대한인간공학회지
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• 제34권1호
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• pp.1-10
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• 2015

Objective: The purpose of this paper is to evaluate old and newly designed ammunition boxes from an ergonomic point of view. Background: The ammunition boxes made of wood, which are currently used by the military, have some difficulties such as corrosion and damage of ammunition, environmental pollution, and stock management. Also, damages to the wooden ammunition boxes take place frequently, because soldiers carry them manually. Method: Sixteen participants volunteered to randomly perform lifting, carrying, and side-by-side moving tasks with 4 different old and new boxes, respectively for the ammunitions of 5.56mm, 60mm, 81mm, and 105mm in diameter. The old boxes are made of wood and are currently used in the military, while the new boxes are made of plastics. The joint moments of the elbow, shoulder, back, and knee were measured by using a motion analysis system and force platforms. In addition, an electromyographic system was used to measure the forces of hand and wrist muscles. Results: In most tasks, new boxes caused less joint moments at the elbow and shoulder than old boxes, because the new boxes were lighter and smaller than the old boxes. New boxes also derived less hand and wrist muscle forces due to the provision of fixed hard handles rather than string handles. Conclusion: The ergonomically designed new boxes could reduce the physical stresses of soldiers manually handling ammunitions and be helpful for storage and reuse. Application: This study shows an ergonomic application example for product development and evaluation.

• Journal of Biosystems Engineering
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• 제42권4호
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• pp.235-241
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• 2017

Purpose: It is to develop an agricultural three-directional dumping vehicle that can help farmers reduce intensive labor when carrying heavy loads and for easy dumping. In addition, a novel mechanism was applied for controlling the direction of the tilting cargo box by using a single hydraulic cylinder and simple apparatus. The overturning safety was analyzed to provide safe-use ground slope region of the vehicle to be used at upland fields and orchards. Methods: The developed three-directional dumping vehicle was constructed using a cargo box, vehicle frame, driving components, lifting components, and controller. The novel mechanism of controlling the dumping direction involves the operation of two latching bars, which selectively release or collapse the connecting edge between the vehicle frame and cargo box. A multibody dynamics analysis software (RecurDynV8R5) was used to determine the safe-use ground slope area when tilting the cargo box at slopes. A computer analysis was conducted by increasing the ground slope while rotating the vehicle when the cargo box comprised loads of 300 and 500 kg and stacking heights of 40 and 80 cm, respectively. Results: The three-directional dumping vehicle was successfully manufactured, and the cargo box was tilted at $37^{\circ}$ and $35^{\circ}$ for dumping forward and sideways. The latching bars were manually and selectively collapsed with the vehicle frame to control the dumping direction. When forward dumping, the safe-use ground slope was over $20^{\circ}$ in all vehicle directions and loaded conditions. Conclusions: A three-directional dumping vehicle was developed to reduce labor-intensive work in the farming environment. The user can easily control the dumping direction by using the control panel. The vehicle was safe to be used in most of the Korean upland fields and orchards (area over 96%) for the forward dumping.