• Transactions of Materials Processing
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• v.17 no.5
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• pp.350-355
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• 2008

Currently, in the automotive industry, the efforts to reduce the manufacturing cost by changing the manufacturing process are continually performed. In this paper, we proposed a new manufacturing process, the roll bending process of a ring plate of automotive fuel tank instead of conventional press blanking process to reduce material loss and manufacturing cost. Finite element analysis was used to optimize the roll bending process to assure rectangular cross-section of the ring plate. Also, spring-back analysis after the roll bending process was performed and dimension of the bending die considering spring-back was analyzed. Finally, we verified a possibility for realization of the proposed method with prototypes.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.311-315
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• 2008

Currently, in automobile industry. the efforts to reduce the manufacturing cost by changing the process of manufacturing are continually performed. In this paper, we proposed a new manufacturing process, the roll bending of a ring plate of automotive fuel tank instead of conventional press blanking process to reduce material loss and manufacturing cost. Finite element analysis was used to optimize the roll bending process to assure rectangular cross-section of the ring plate. Also, spring-back analysis after the roll bending was performed and dimension of the bending die considering spring-back was analyzed. Finally, we verified a possibility for realization of the proposed method shape with prototypes.

• Journal of the Korean Geotechnical Society
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• v.32 no.12
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• pp.45-57
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• 2016

The Inclined Earth Retaining Structure (IER) is the structure using an integrated system of both front supports and inclined back supports to increase the stability for excavation. The IER is a structurally stable temporary excavation method using the back supports restraining the lateral displacement of the front supports as stabilizing piles. The back supports connected to the front supports significantly reduce the earth pressure acting on both the front wall and the front supports by distributing it to the back supports in order to increase the structural stability. In this study, mechanical behaviors of IER according to the head connection type using fixed- or hinge-connection were found by performing numerical analysis and laboratory model tests in the sandy ground. The maximum lateral displacement of fixed-connection was 88% of that of hinge-connection in the numerical analysis. The lateral displacement of fixed-connection was 7% of that of hinge-connection in the laboratory model test results. Furthermore, the earth pressure of the fixed-connection was 67% of that of the hinge-connection in the shear-strain analysis results of the model ground.

• Journal of the Korean Ceramic Society
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• v.38 no.2
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• pp.193-198
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• 2001

유한요소법을 이용하여 STS VOD 래들에서 내장 내화물의 재질 및 back filler의 시공 위치에 따른 열응력을 수행하였다. 불소성 내화물의 경우 높은 열전도율에 의해 가동면과 배면(back face)간의 온도구배가 소성품에 비해 감소하였으며 탄성계수도 낮아 발생되는 열응력이 2~4배 낮았다. Back filler는 dolomite 내화물의 열간 팽창을 흡수하기 위해 시공하는 것으로, 상대적으로 낮은 열전도율을 가지고 있기 때문에 back filler의 내부와 외부에 급격한 온도구배가 발생된다. 결과적으로 래들의 내부는 고온을 유지하여 내화물이 팽창이 되고, 외부는 온도가 낮아지므로 수축되어 열응력이 증가하였다.

• The Korean Journal of Rehabilitation Nursing
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• v.9 no.1
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• pp.42-48
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• 2006

Purpose: The purpose of this study was to explore the effect of Tai Chi exercise on pain, balance, gait and physical function of patients with low back pain. Method: This study was designed one group pretest-posttest design. Tai Chi exercise was conducted by researcher and carried out for sixty minutes per one time and two times a week for six weeks. The subjects of this study consisted of 23 low back patients. Using the SPSS win 10.0 program was used for data analysis, which included frequency, percentage and paired t-test. Result: Tai Chi exercise decreased pain, improved balance and gait, increased physical function(back muscle strength, leg muscle strength and flexibility). Conclusion: The results suggested Tai Chi exercise can be effective nursing intervention to improve pain, balance, gait and physical function of patients with low back pain.

• Journal of the Korean GEO-environmental Society
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• v.11 no.7
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• pp.5-14
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• 2010

The paper processed settlement analysis using Finite Elements Method(FEM). Because Stress Distribution Ratio has to be decreased, for settlement analysis of soft clay deposit improved by sand compaction piles(SCP). Back analysis was processed comparing the measured settlements of laboratory model tests and finite element analysis where the SCP treated area was assumed as mixed ground with clay deposit rather than being a composite ground. The paper proposes a methodology which employs a compression index($C_c$) for settlement analysis of soft clay deposit improved by sand compaction piles from the back analysis. This approach is applied to a field measurement case(A revetment founded on the SCP improved clay deposit with the replacement ratio of 45%).

• Journal of Preventive Medicine and Public Health
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• v.43 no.6
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• pp.505-512
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• 2010

Objectives: Because of the changing life style of Koreans, we have witnessed an increase of patients with back pain. The development of medical knowledge and technology has resulted in more numerous and better treatment methods. However, the outcomes of diverse treatments have been examined by using a few medicine-oriented measures like pain. This study aims at identifying the factors that influence the outcomes of back pain treatments by using two outcome measures (e.g., quality of life and pain). Methods: We used the questionnaire survey method for data collection. The questionnaires contained 5 categories (treatment methods, clinical conditions, exercise, quality of life and, socio-demographic characteristics). We interviewed 188 back pain patients. We used the regression analysis method to predict the quality of life or pain. Results: Surgery showed a statistically significant effect on the quality of life as well as pain. The illness period, age and exercise were turned out to be significant factors for both of the dependent variables. The social class and surgery methods showed a statistically significant effect solely on the quality of life. Conclusions: In choosing the surgical methods, doctors need to provide detailed explanations on the quality of life outcomes for each of the surgical methods to the patients.

• Journal of the Ergonomics Society of Korea
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• v.30 no.2
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• pp.349-356
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• 2011

Objective: The purpose of this study was to analyze the risk factors of the musculoskeletal workload of mid-old-age female caregivers by identifying work postures and subjective symptoms. Method: This study was carried out on a total of 206 subjects 206 mid-old-age caregivers(45~65 years old) from November 2009 to April 2010: 206 mid-old-age caregivers (45~65 years old) at the long-term hospital. A questionnaires survey on general factors and subjective symptoms of subjects was conducted. The risk factors of the musculoskeletal workload evaluation method is based on OWAS, RULA, REBA according to occupation properties. Results: The analysis of the rates of the subjective symptoms showed that 78.6% subjects experience low back pain. The analysis of the work type showed that transfer is the highest rate(36.3%) and position change is the second(18.2%). The analysis of the work postures showed that the thrusted back with twisting position over $20^{\circ}$ is highest rate(37.4%), the bended back forward with twisting position is the second(27.5%). Conclusion: This study suggested that the need of preventive education for caregivers and workload improve. It is hoped that subsequent study on the difference of subjective symptoms between educated caregivers and non educated caregivers will be conducted.

• Design & Manufacturing
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• v.17 no.2
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• pp.47-54
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• 2023

The research direction of the automobile industry worldwide is speeding up research to improve fuel efficiency through weight reduction as the weight of automobiles increases due to environmental problems, convenience demands, and safety problems. As a way to solve weight reduction, there is a method of improving mechanical properties by improving the development and manufacturing method of lightweight materials with replaceable mechanical properties. Therefore, research on the molding and processing technology of aluminum, which is a lightweight material, is being actively conducted. In this study, aluminum material was applied. By using Autoform S/W, a press forming analysis program, the blank holding force, mold die R, and bead restraint force were selected in three levels, respectively, and the results and optimization of formability and shape freezing were carried out. In this study, aluminum material was applied. By using Autoform S/W, a press molding analysis program, the blank holding force, mold die R, and bead restraint force were selected in three levels, respectively, and the results and optimization of formability and shape freezing were carried out. The optimized results were confirmed by comparative analysis of formability and Spring Back. As a result of the experiment, it was possible to confirm the result value of the Spring Back of the final product according to the tensile change of the material.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.792-795
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• 1996

In TIG welding of pipe, back bead size monitoring is important for weld quality assurance. Many researches have been performed on estimation of the back bead size by heat conduction analysis. However numerical conduction model based on many uncertain thermal parameters causes remarkable errors and thermomechanical phenomena in molten pool can not be considered. In this paper, filler wire feeding force in addition to weld current, wire feedrate, torch travel speed and orbital position angle is monitored to estimate back bead size in orbital TIG welding. Monitored welding process variables are fed into an artificial neural network estimator which has been trained with the monitored process variables (input patterns) and actual back bead size (output patterns). Experimental verification of the proposed estimation method was performed. The predicted results are in a good agreement with the actual back bead shape. The results are quite promising in that estimation of invisible back bead shape can be achieved by analyzing the welding parameters without any conventional NDT of welds.