• Journal of Korean Institute of Industrial Engineers
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• v.42 no.6
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• pp.404-411
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• 2016

In footwear manufacturing systems, the upper parts of the shoes are manually sewed on a sub-line while bottom parts are produced by machines such as injection and molding machines on a sub-line before these two parts are combined into complete shoes on a final assembly line. The manual operations for the upper parts lead to a large variability in processing times, resulting in higher work-in-process inventory. In most footwear industries, production lines have been controlled by MRP-based push systems. Some industries attempt to introduce Kanban-based pull systems. This paper identifies the characteristics of the footwear manufacturing processes, and discusses the problems of the current control systems. As an operational alternative, a CONWIP-based control strategy is presented. Simulation experiments are performed to examine the performance of the control strategies.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.5
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• pp.538-544
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• 2012

In this paper, design optimization of C-frame of a precision drilling and autorivet machine has been performed. The machine, Autoriveter has been developed by Korea Aerospace Industry (KAI), For current autoriveter, it is hard to achieve high efficiency because of heavy weight of the machine. In this paper, we suggest new structure of the current C-frame, a part of autoriveter, by optimization. The result of the study can give much profit for mass-production of the machine.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.279-284
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• 2016

Finite element analysis along with DOE scheme has been performed to obtain robust design of crankshaft assembly. This study focused on obtaining optimized fillet radius of crankshaft mainly by statistical approach. 27 design cases using 3 factors with 3 levels are constructed by design of experiment. Changes of design factors and noise factor may influence the durability of crankshaft system. General two stages of robust design may enhance the durability of crankshaft model. Increasing crank arm thickness was adopted as a shrink step and change of fillet radius was used as a shift step. By combining these two steps, the stress concentration at the fillet area is reduced and adequate fillet radius is determined for the robust design of crankshaft.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.35.1-35.1
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• 2008

The importance on the simulation of earth observation optical payloads has been recently emphasized in order to estimate on-orbit imaging performance of the payloads. The estimation should consider all aspects of payload development; design, manufacture, test, assembly, launch and space environment. Until recently several studies have been focused the evaluation of the individual factors rather than the integrated. This paper presents the development of an integrated payload simulator. The simulator analyzes the payload imaging performance based on MTF(Modulation Transfer Function) calculations of the major factors (Diffraction, Aberration, Detector integration, Image motion and etc.) and the simulator can generate realistic artificial earth images as taken by defined earth observation payloads. The simulator is developed for the use of evaluating pre- and post-launch imaging performance and assisting on-board calibration of COMPSAT-3.

• Journal of the Korean Society of Safety
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• v.35 no.4
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• pp.40-47
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• 2020

Although gangform has good workability due to the integration of outer wall forms and working platforms, 22 workers were died from 21 gangform related accidents during 2012 to 2016. Quantitative risk assessment is required for evident based prevention measure selection. In this study, based on 52 accident data from 2004 to the first half of 2019, FTA is conducted for probabilities of direct causes and their contribution to accidents. Three stages are considered; gangform installation, dismantling and lifting, and using. The effectiveness of countermeasures is evaluated through minimum cut set, RAW and RRW. Complete assembly of gangform on the ground level, detailed planning, and fall prevention device are suggested as prevention measures for installation, dismantling and lifting, and using stages, respectively.

• Journal of Korean Academy of Nursing Administration
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• v.9 no.1
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• pp.113-128
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• 2003

Purpose : The aim of this study is to review cost analysis methodological issues in the nursing literature. Method : The subjects of this study were articles published in Korea from 1961 to August, 2002. They were searched by key words 'cost' and 'nursing' from various DB(National Assembly Library, The National Library of Korea, RICH etc). Finally, 31 articles were collected. Results : 1) The major type of cost analysis was a cost comparison study. 2) The important methodological weaknesses were as followers: First, many studies did not describe a cost analysis framework or a cost analysis assumption. Second, a few studies described selection criteria of cost items and effectiveness items. Third, many studies did not do a sensitivity analysis. Conclusion : With these results, it will be possible to develop a more proper cost analysis methodological framework and also to make an evaluation criteria for cost analysis nursing study.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1727-1731
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• 2014

Dichloromethane liquid droplets containing a cobalt dipyrromethene trimer deposited on a graphite surface were found to form coffee ring, toroid ring, or volcano dot structures due to the redistribution of the solute during solvent evaporation. The shapes and size distributions of the ring structures depended on the drying temperature. The shape differences were attributed to the fact that the solvent evaporation rate controlled the self-assembly process that yielded the coffee stain and pinhole structures.

• Journal of Home Health Care Nursing
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• v.10 no.2
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• pp.113-122
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• 2003

Purpose: This is a simple survey for discussion about cost analysis methodological issues in home care nursing service studies. Method: The subject of this study were articles published in Korea from 1961 to August, 2002, and searched by key word 'cost' and 'nursing' from various DB(National Assembly Library, The National Library of Korea, RICH etc). Finally, 13 articles were collected. Result: 1) The major type of cost analysis studies was a cost comparison or a simple cost study. 2) The important methodological weaknesses were as followers; (1) few studies were suggested cost analysis framework or analytic perspective, (2) it ,was not enough to describe for basis of selection of cost/effectiveness items, (3) few studies were done by sensitivity analysis. Conclusion: These above results will be used to develop a more proper cost analysis methodological framework in home care nursing services and also to contribute as a guideline for further studies.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.82.1-82.1
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• 2017

After a coronal mass ejection occur, plasma blobs are often observed along the post-CME ray. Searching for features related to the plasma blobs would be important in understanding their origin. We investigated the morphology of solar flares at EUV wavelengths, around the estimated times when blobs were formed. We focused on three events - 2013 September 21 and 22, 2015 March 7 and 8, and 2017 July 13 and 14 - observed by Atmospheric Imaging Assembly (AIA) aboard Solar Dynamic Observatory (SDO). Around the blob ejection times on 2013 September 21 and 22 and 2017 July 13 and14, we found regions with recurrent events of pronounced flux increase in EUV images. Around those of 2015 March 7 and 8, however, we could not observe such recurrent flux increase. This illustrates that even though blob ejections along different post-CME rays look similar in the high corona, the assocated features in the low corona may differ. We conclude that magnetic morphology and CME triggering process should be carefully examined in order to classify plasma blobs by their nature.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.9-16
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• 2017

This study describes the development of a 1-inch cryogenic glove valve for an LNG pumping system and localization development achieved through the performance test. The cryogenic valve used in the LNG pumping system plays an important role in maintaining a flow rate by LNG transportation. This trial manufactured goods, which was achieved through reverse engineering and developing the assembly process. The result of the leak test satisfied the internal pressure condition using the 78-bar normal temperature test and maintained the anti-leakage condition. Also, the result of the cryogenic leak test (BS 6364: low temperature test procedure) maintained anti-leakage at -196 and 52 bar, which satisfied the test standards.