• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.587-596
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• 2021

Naval battleships have systems to perform special purposes, such as the Command and Fire Control System (CFCS). Some of the this equipment should be equipped with an Uninterruptible Power System (UPS ) to ensure operational continuity and the backup of important data, even during unexpected power outages caused by problems with the ship's power generator. Heavy combat losses can occur if the equipment cannot satisfy the function. Therefore, it is important to design a stable UPS. The battery and Battery Management System (BMS) are two of the most important factors for designing a stable UPS. A power outage will be encountered if the battery and BMS are not stable. The customer will be exposed to abnormal situations, loss of important tactical data, and inability to operate some of the CFCS. As a result, an enhanced safety system should be designed. Thus, this study implemented and verified the improved system in terms of three methods, such as comparative analysis of the batteries, improvement about leakage current of the circuit, and tests of the aggressive environmental resistance to improve the UPS for CFCS.

• Journal of Fashion Business
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• v.27 no.2
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• pp.26-38
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• 2023

This study aimed to develop a visually differentiated quarantine suit design for giving 119 paramedics comfort to work and psychological stability and to awaken awareness without fear or pressure of the public through literature review and practical research. Basic research was conducted on firefighting uniforms and quarantine suits in Korea and abroad, focusing on domestic and foreign related literature. An interview survey was conducted to identify the current status, problems, and preferences of the design. Research subjects were eight dispatched paramedics and two executives in Seoul and Gwangju. The survey period was from September 15, 2022 to October 10, 2022. Interviews were conducted through phone calls. Results of this study were as follows. Most of the quarantine suits currently worn were Level D style ready-made clothes without coverall patterns. The current quarantine suit was designed without reflecting the symbolism of the National Fire Agency. They were wearing a generous size without having to think about the fit. Most of these quarantine suits were white. In addition, the quarantine suit could not be equipped with a camera for the safety of paramedics. After identifying improvements based on results of the above interview analysis, the following quarantine suit design was proposed. First, it would be differentiated from other institutions by designing suits with symbolism. Second, the convenience of size, camera equipment, and better breathability and style than Level D should be considered. Based on these results, a total of five quarantine suits were designed.

• Journal of Korean Society for Quality Management
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• v.39 no.1
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• pp.131-140
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• 2011

Today, due to the global recession car sales have been decreased rapidly and auto makers are competing continuously to expand their market share. Automakers are struggling in order to secure competitive cost and quality through continuous cost reduction and quality innovation activities to win in the competition. In this situation, auto parts makers are trying to reinforce price competitiveness by reducing COPQ (Cost Of Poor Quality) in the mass production stages by securing the quality of components in advance from the design stage through DFSS (Design For Six Sigma) activities which is 6 sigma approach in the R&D field. However, auto parts makers have been undergone various confusion, feeling difficulties to get interrelationship among various activities. Thus, this study is going to suggest approach method for much more effective R&D activities by securing interrelationship between ISO/TS 16949 system established in the auto parts industry and DFSS activities.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.3
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• pp.243-249
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• 2014

Currently, CFRP composites are rapidly replacing steel plates, as they are lighter, stronger, and more elastic; however, they are poorly suited to hygrothermal and impact-collapsed environments because moisture can alter their molecule arrangement and chemical properties. In this study, environments are experimentally simulated in order to investigate changes in the moisture absorption inside a CFRP composite and to determine its weakest point. Moreover, changes in the moisture absorption ratio at temperatures of $60^{\circ}C$ and $80^{\circ}C$ are studied and compared in order to understand how changes in temperature affect moisture absorption inside CFRP composites. Results show that moisture absorption leads to a strength reduction of around 50%. In addition, the moisture absorption rate inside CFRP composites is shown to change rapidly with increasing temperature. Accordingly, it showed that the change in matrix also has a weak point.

• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.106-109
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• 2006

In this paper, the design and characteristics of a novel ultrasonic motor are investigated. Such a motor is appropriate far use in the optical zoom or auto focusing functions of the lens system in mobile phones. Its design and simulation of performances are carried out by FEM commercial software (ATILA). The shape of the motor is similar to a square without one side, on which an optical lens can be mounted. Two sheets of piezoelectric ceramics are adhered to both sides of two legs of the elastic body, respectively To drive the ultrasonic motor, the voltage is applied to two sheets of piezoelectric ceramics bonded to one leg. The rotation direction can be easily changed by switching the piezoelectric sheets bonded to the other leg, to which voltage is applied. A proto type of the motor is fabricated and its outer size is $10^*10^*2[mm3]$ including the camera lens of which the diameter is 7.5(mm). Its power consumption is about 0.3[W] and the speed of rotation is adjustable from 10 to 200[rpm] according to the applied voltage

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.949-952
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• 2010

The utilization of LPG(Liquefied Petroleum Gas) is increasing as an environmental-friendly fuel in all countries making green growth new paradigm, and use of gas is spread fast as motor fuels to decrease air pollution. Loss of lives by explosion and fire is happening every year as gas use increases, and gas accident in large scale storage property is causing serious problems socially. To minimize this problem, underground containment type storage tank is being presented as an alternative recently. In this study, to minimize explosion occurrence in underground containment type storage tank, the suitable storage tank is designed to consider explosion prevention that makes exposure surface area minimize in confined contents volume and flame to construct storage tank by the most suitable condition in the underground containment room. As a result of the design of storage tank having the most suitable condition by this research, underground containment space was minimized on diameter 3m, length 4.83m in 20 tons storage tank and its safety was improved as exposure surface area in flame decreased by 89.4%, compared with the existent storage tank.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.2
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• pp.38-45
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• 2015

This paper describes an ejector design technique which used for simulating low pressure environment corresponding to high altitude. Also the ejector performance characteristics was investigated according to performance and geometric variables by cold gas flow test. Entrainment ratio, compression ratio and expansion ratio were designated as performance variables and an ejector gap ratio was designated as a geometric variable. A relationship between the performance variables to predict the ejector performance was identified and it was confirmed that the performance variables have much more effective than the ejector gap ratio through the ejector cold gas flow test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.133-137
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• 2010

A dual pulse solid rocket motor has several advantages compared to the single one. The range and the terminal velocity of the guided missile can be remarkably increased by the application of the pulse separation device(PSD) to the solid rocket motor which resulted in appropriate thrust distribution. In this study, the subscale dual pulse solid rocket motor with the bulkhead type PSD was designed, manufactured, and fire-tested. The bursting pressure, thermal characteristics, and the structural safety of the PSD were obtained by the tests and the results will be applied to the design of full-scale dual pulse rocket motor.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.4
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• pp.221-229
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• 2019

Several water tanks installed in the building were damaged during the Gyeongju earthquake (2016) and the Pohang earthquake (2017). Since a water tank for fire protection is very important component, seismic safety should be ensured. In this study, an interaction between a water tank and a building was studied by the dynamic analysis of the RC building with the water tank. In case the water tank was installed on the roof of the RC building, it was confirmed that it did not significantly affect the response of the building. Based on the result, dynamic response characteristics of the water tank in the building were studied using two SDOF models represented dynamic behavior of the water tanks under earthquake. An earthquake time-history analysis was carried out with variables of aspect ratio of the tank, story of the building, and installed location in the building using three kinds of earthquakes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.80-86
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• 2020

With the exception of welding activities, it is forbidden to use electricity in shipyards, owing to safety concerns such as the possibility of fire, explosions, and short circuits. In this paper, an automatic chamfering machine using pneumatics is proposed for use in such environments. Customers specify their requirements and the machine derives the corresponding theoretical design conditions. The proposed machine was used to perform 3D modeling, and its suitability and performance were confirmed via cutting experiments of the manufactured device. Two types of sensors may be used in this system: contact and non-contact. In the case of the contact type, an end-stop switch that can recognize the end of the material is installed, and when the machine reaches the end of the material, the end-stop switch is operated to cut off the air pressure. In the non-contact type, four sensors were used: photonic, ultrasonic, metal detection, and encoder. The use of the four sensors was repeated 30 times, and the average error determined. Thus, the optimum sensor was identified.