• Journal of the Ergonomics Society of Korea
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• v.34 no.1
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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.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.334-343
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• 1996

Quality evaluation for food and agricultural products have always been one of the most elusive problems associated with the handling , processing and marketing in a food plant production. In order to detect physical foreign materials in food and agricultural products, non-destructive techniques have been developed for many years. Application of X-ray system to detect physical foreign materials in food and agricultural products could be considered to be a high potential method. Especially , it is impossible to detect internal physical foreign materials by visual inspections. In this study, it was tried to be applied for two different X-ray devices. Soft X-ray system with CdTe sensor and X-ray CT scanner were evaluated for advantage of the detection of non-meltallic foreign materials in food and agricultural products . Though the soft X-ray is not a high energy radiation, it is possible to detect small different density in a material. The CdTe sensor has a high resolution for t e soft X-ray energy region. The density characteristics of foods and foreign material were expressed region. The density characteristics of foods and foreign materials were expressed as a soft X-ray energy spectrum. The energy spectrum was analyzed by a personal computer with a multi-channel analyzer. X-ray CT scanner can provide visual image and analyze by three dimensional information inside food and agricultural products. The X-ray CT scanner using as a medical equipment was used to detect a foreign material. The density characteristics of food and foreign materials in food were tried to be detected by the threshold value on the basis of the CT numbers. The soft X-ray absorption characteristics for acrylin plates and distilled water were obtained and could be found the possibility of detecting a small physical foreign materials such as a plastic wrapping film , a stone and grasshopper in food and agricultural products.

• Proceedings of the Korean Geotechical Society Conference
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• 1993.10a
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• pp.33-42
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• 1993

Geocell is a three dimensional cellular confinement system that forms a reocomposite mattress with infill material to increase the bearing capacity dramatically rather than geotextiles of nonwoven and woven fabric type and geogrid. In terms of design, this geocell confinement is quite complex to assess and is different in its hieoretical evaluation and its concept from other geosynthetic products. Thsi study is aimed to help a basic understanding on Geoweb system, which is known to be the most effective and easiest in handling among the geocell systems ever developed, by introducing two method of interpretation for the improvement of bearing capacity. Thus the writers are sillingly to help the geotechnical engineers and the site engineers who might be encountered with the bearing capacity problems on site.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.38
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• pp.9-15
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• 1996

The purpose of this research is to develop a method for part-machine grouping subject to production and management constraints. In the proposed integer programming model, minimization of operating and material-handling costs are considered as an objective function. The model allows one to recognize the existing parts and machines into disaggregated cells. New constraints are introduced in the model to resolve unbalancing capacity and bottleneck problems. It is found that this approach could have a better flexibility on cell size design for mote alternatives than conventional methods. Experimental grouping and comparison studies with ROC algorithm are given for evaluation purposes.

• Journal of the Ergonomics Society of Korea
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• v.34 no.3
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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.

• IE interfaces
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• v.20 no.1
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• pp.21-32
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• 2007

This paper deals with the simulation model for A-Mart logistic center design and operations. In developed simulation model, receiving docks, conveyor sorter, conveyor system, shipping docks, material handling devices and manual sorting stations are considered. Three types of cargo such as transfer center cargo, distribution center cargo and supermarket cargo are considered. The simulation model and process animation are developed using the simulation package ARENA. Among various design and operation alternatives consisting of the number of workers of receiving dock, allocation of receiving docks by cargo types, conveyor sorter velocity, the number of folk-lift, the number of manual sorting operators and overall layout, the best alternatives of each subsystem are selected by simulation analysis. The major performance measures such as sorter throughput, utilization of operators at each station, receiving docks utilization and folk-lift utilization are considered for the alternative evaluation.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.826-831
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• 1991

Automated Storage and Retrieval System (AS/RS), which is an element of Computer Integrated Manufacturing (CIM), is a widely used material handling equipment with conveyors and Automatic Guided Vehicles (AGVs). Until now the evaluation of operational policies of AS/RS and control algorithms is done theoretically or by computer simulations. In this study, a real-time control and monitoring software of an AS/RS is also developed by making actually moving AS/RS miniature. A PC-based real-time monitoring program can control the AS/RS directly through the communication port. The monitoring program has additional functions such as storage/retrieval management, inventory management, and statistics management. The program can not only collect the necessary statistics but monitor the current action of the AS/RS concurrently.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.4 s.247
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• pp.306-313
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• 2006

Automated material handling system is being used as a method to reduce manufacturing cost in the semiconductor and flat panel displays (FPDs) manufacturing process. Those are considering switch-over from the traditional cassette system to single-substrate transfer system to reduce raw materials of stocks in the processing line. In the present study, the wafer transportation speed has been evaluated by numerical and experimental method for three propulsion nozzle array (face, front, rear) in an air levitation system. Test facility for 300 mm wafer was equipped with two control tracks and a transfer track of 1,500mm length. The diameter of propulsion nozzle is 0.8mm and air velocity of wafer propulsion is $50\sim150m/s$. We found that the experimental results of the wafer transportation speed were well agreed with the numerical ones. Namely, the predicted values of the maximum wafer transportation speed are higher than those values of experimental data by 16% and the numerical result of the mean wafer transportation speed is higher than the experimental result within 20%.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.1
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• pp.68-75
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• 2023

In an automotive plant, an automated storage and retrieval system (ASRS) synchronizes material handling flows from a part production line to an auto-assembly line. The part production line transfers parts on small-/large-sized pallets. The products on pallets are temporarily stored on the ASRS, and the ASRS retrieves the products upon request from the auto-assembly line. Each ASRS aisle is equipped with narrow-/wide-width racks for two pallet sizes. An ASRS aisle with narrow-/wide-width racks improves both storage space utilization and crane utilization while requiring delicate ASRS aisle design, i.e., the locations of the narrow-/wide-width racks in an ASRS aisle, and proper operation policies affect the ASRS performance over demand fluctuations. We focus on operation policies involving a common storage zone using wide-width racks for two pallet sizes and a storage-retrieval job-change for a crane based on assembly-line batch size. We model a discrete-event simulation model and conduct extensive experiments to evaluate operation policies. The simulation results address the best ASRS aisle design and suggest the most effective operation policies for the aisle design.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.35-43
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• 2024

With continuous advancements in industry, science, and technology, there is a steady increase in the number and utilization of new chemicals. The growing societal emphasis on chemical safety management is paralleled by an increasing public demand for robust safety measures. While various ministries at the government level oversee the safety management of chemical substances, the occurrence of accidents related to chemical substances remains frequent each year due to problems such as aging facilities and careless handling. Upon analyzing domestic chemical accident cases, incidents occurred predominantly in the sequence of leakage, explosion, fire, and others. The main causes of these accidents were examined, revealing facility defects and non-compliance with safety management as the primary contributing factors. In this study, Hazard and Operability Analysis (HAZOP) was employed to identify hazardous risk factors associated with the handling of hydrofluoric acid in workplaces, and a risk assessment was performed using Bow-Tie method. Based on the results of this study, it is expected to enhance safety management plans aimed at preventing chemical accidents in workplaces dealing with similar facilities. Ultimately, these insights contribute to the development of an advanced chemical safety management system, capable of proactively preventing potential chemical accidents.