• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.47-57
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• 1997

As a general index in surface quality of machined products, surface roughness is to measure worker's skill level, a ground product quality and machining accuracy, etc. The surface roughness is defined by a function of rotational speed and radius of a grinding wheel, distances of active grains composed of the wheel, and feed of a grinder's worktable. To predict surface roughness in horizontal surface grinding operations, probability distributions were used. Probability distribution functions(p.d.f.) of surface roughness were found as results when the size of active grains(=the radius of a grinding wheel) is given as uniform, exponential distribution, and the distance between active grains follows the distributions of uniform, exponential. For each pdf case, probabilistic features of surface roughness were also analyzed and presented. This study is a substantial step for determining mathematically the surface roughness instead of using empirical approaches. More works should be presented to develop a general model by which an accurate roughness value can be obtained in horizontal surface grinding operations.

• Journal of the Korea Safety Management & Science
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• v.7 no.2
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• pp.85-94
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• 2005

The purpose of this study is to execute the investigation of injurious factors causing muscle-skeletal diseases at an automotive glass manufacturing company and, on the basis of the results, to enhance productivity by the improvement of working environment. By using an survey and an ergonomic evaluation method, symptoms of muscle-skeletal diseases of workers and working postures at each process were analyzed, and quantitative evaluation of muscle-skeletal disease risk against each process was performed. Based on the result of the evaluation, to enhance the working environment, improvement of worktable, working space, tools, and outfit was suggested, and induction of mechanical system was also suggested. Suggested improvement plan was applied to the workplace step by step and it is confirmed that improvement plan not only removes the injurious factors of muscle-skeletal diseases but also is effective to enhance productivity.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.5
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• pp.48-52
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• 2019

A coolant pump is the device that cools processed articles and tools when using cutting, boring, and grinding machine tools and provides cutting oil for distributing or cleansing the cut chip to the worktable, processing position, etc. In particular, it consumes a large proportion of energy in machine tools, so it plays an important role in terms of energy efficiency. The purpose of this research is to optimize the shape of impeller, which directly affects performance improvements, to determine the capacity of the coolant pump. To do so, we carried out a parametric analysis with the geometric shape of the impeller as the input variable.

• Journal of the Korean housing association
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• v.22 no.5
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• pp.71-80
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• 2011

The purpose of this study is to investigate the present status of dwelling spaces and deduct sustainable elements in transformation of them by comparing the restored drawings with the surveyed drawings focused on traditional houses that exist in the urban area of cheongju city in Korea. In alteration and extension of these traditional houses, scale of a private room became larger as it has been connected and expanded, the exterior main hall (Daecheong) became the interior living room, and the conventional kitchen was westernized and changed from K type to DK or LDK type. The toilet located at outside was installed by the attached aisle (Toetgan) inside and the existing room. The extension was completed with equipments, storage space, and rental accommodation. The conservative and sustainable elements in the various transformation of them are as follows. Firstly, it was to maintain 3 rooms such as main room (anbang)-main hall (daecheong)-detached room (gunnunbang). Secondly, it was to sustain the circulation of kitchen and arrangement of the - type worktable even though it was westernized. Thirdly, extension of storage space was completed less than 600 mm within the eaves. Although there were functionally and structurally many changes in 18 houses, 4 houses had maintained wooden floor of main hall, 5 houses long planked wooden floor of the attached aisle, and 12 houses rafter ceiling of the main hall and the attached aisle.

• Journal of the Korean housing association
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• v.26 no.1
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• pp.91-98
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• 2015

The purposes of this study are to analyze the problems of the elderly using kitchens by ergonomic work evaluation methods, and to make suggestions for planning and remodeling of the kitchens for the elderly. The work evaluation methods which used in this study were direct-observing methods, which contained the process of 2 or 3 times each visiting to four different houses where elderly people live. For direct-observing methods, analyzing with movement observations and observation methods with photos and videos were used. Characteristics of subject elderly people and problems of their kitchens were analyzed by static measurements, interviews, pictures, and videos. The data, which are recorded movements of the preparing meal of the elderly were analyzed by playing it back repeatedly. As results, physical characteristics of the elderly was the most important consideration; a participant with the arthritical knee was limping at the kitchen entrance due to the difference of the floor level, and a user with a bent back was working on the floor or place an elbow on the worktable to support her body. Those results made a conclusion about the common problems of the kitchens, and suggested the check list which has to be considered when designing the elderly using kitchen.

• Journal of the Korea Safety Management & Science
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• v.11 no.2
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• pp.51-57
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• 2009

The goal of this study is to propose the effective method of investigating the injurious factors and make improvement plans that prevents the workers against musculoskeletal disorders at plastic product companies and the same business field with similar working conditions and process. A questionnaire are adopted to analyze the symptoms of workers' musculoskeletal disorders, and ergonomic assessment methods such as RULA, OWAS are performed to find out harmful factors of workplace and working posture. Based on the result of the evaluation, to enhance the working environment, improvement of worktable, working space, tools, and outfit was suggested, and induction of mechanical system was also suggested. It can be concluded that the method and process described in this paper could be helpful for diagnosing the musculoskeletal disorders risk factors and making improvement plans to the plastic product companies and the same business field with similar working conditions and process.

• Journal of the Korea Safety Management & Science
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• v.11 no.2
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• pp.59-67
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• 2009

The goal of this study is to propose the effective method of investigating the injurious factors and making improved plans that prevents the workers against musculoskeletal disorders at an diesel engine manufacturing company and the same business field with similar working conditions and process. A questionnaire were adopted to analyze the symptoms of workers' musculoskeletal disorders, and an ergonomic assessment method such as RULA, OWAS were performed to find out harmful factors of workplace and working posture. Based on the result of the evaluation, to enhance the working environment, improvement of worktable, working space, tools, and outfit was suggested, and induction of mechanical system was also suggested. It can be concluded that the method and process described in this paper could be helpful for diagnosing the musculoskeletal disorders and making improvement plans to the diesel engine fuel injection system manufacturing company and the same business field with similar working conditions and process.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.6
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• pp.551-558
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• 2015

The purpose of this paper is to investigate the development of mechanical projectile transfer system to prevent musculoskeletal problems in the firing test range. Prior to 2010, the projectile has been transferred from the worktable to the loading device of 155mm K9 fixed-type artillery by manual. Because the amount of firing test has been increased drastically since 2010, two types of mechanical projectile transfer system were developed to prevent musculoskeletal problems. The NIOSH lift equation and the working posture assessment system such as OWAS, RULA and REBA were used to evaluate the appropriacy of working weight and posture by manual transfer of projectile. The configuration and operation procedure of projectile transfer systems which were developed to improve work efficacy and to reduce the burden of manual transferring were described. The improvements were assessed by the number of processes, the tact time and the working posture assessment for operation of this system by comparing to the manual transfer of projectile.

• The Journal of Korean Physical Therapy
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• v.18 no.6
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• pp.67-75
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• 2006

Purpose: Many kinds of musculoskeletal disease and symptom are caused by the longtime computer works. However, trapezius muscle tonus has not been established in regarding to keyboard height during typing. Therefore, this study is to evaluate the relationship between trapezius muscle tonus and the height of keyboard while typing, controling for the postures of neck, Lumbar, cervical vertebra. Methods: The experimental height of keyboard was set at elbow height, 3cm higher, 6cm higher, 9cm higher, than elbow. We studied trapezius tonus with the mean value for 2 minutes by EMG in 15 males and 15 females worker of hospital in seoul, who did not have a history of muscle disease, neurological signs, nerve damage. Results: In this experimental, as the height of the keyboard went up, the trapezius tonus significantly increased with shoulder abduction of brachium. Second, right and left trapezius tonus appeared similar while typing. Third, the best height that release the trapezius tonus the was as high as elbow and 3cm higher than elbow. Conclusion: With these above results, we suggest that the appropriate height of keyboard during typing to release the trapezius tonus most is the height of the elbow and 3cm higher than elbow. The study has important implications for focusing on the height of VDT worktable and complaining of a pain by oneself which are useful to establish a method of prevention of musculoskeletal disorder in work in the future.

• Journal of the Korean Institute of Educational Facilities
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• v.8 no.3
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• pp.25-35
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• 2001

This study investigated technology education, laboratory management and facilities in middle schools with the goal of finding problems. Ninety-six randomly selected schools and questionnaire was done to the teachers of 84 schools which have laboratory. Five of these schools received on-site inspections. The results of study are as follows : 1) 12.5% of schools have no laboratory. The average laboratory has less than 50% of the necessary equipment for total operations. laboratories are used an average of once or twice per two time frame. 2) 80%of the laboratories are located at the end of a row of regular class rooms. The most common laboratory style is classroom plus hallway($90m^2$) style. 77% of laboratories have a single entrance. 3) 69% of teachers reported the worktable arrangement to be inconvenience. 68% of the schools have 9 worktables per laboratory. 38% say the worktables are not wide enough and 36% said they were appropriate. Table dimensions range from $95{\sim}110cm$ in width and from $210{\sim}225cm$ in length. 65% of the teachers say table height is low with a range from $76{\sim}82cm$. 86% of the teachers say that the height of chair is low and the range of its measurement is from $37{\sim}47cm$. 84% of the teachers points out that laboratory is poorly lighted.