• 품질경영학회지
• /
• 제47권3호
• /
• pp.401-415
• /
• 2019

Purpose: When the SURION Aircraft operated in the fields, cracks are found in PU(polyurethane) Strip on main rotor blade. This study has been conducted to explain PU(polyurethane) Strip crack phenomenon of SURION main rotor blade and to propose useful solution of it by experimental method. Methods: This study considered a lot of factor because the SURION is operated at severe environment. This study investigated the influence of temperature, thermal shock, paint and primer process, PU Strip material, primer material. Results: The results of this study are as follows; The primer process was most excellent influence. The Application of primer having a brittleness caused by a crack of PU Strip. Other factors have influenced on the PU Strip, but they can not be controlled because they are related to the SURION's operating environment. Conclusion: The Quality of PU Strip on SURION main rotor blade was improved through removing the primer process. Finally, the reliability of main rotor blade was guaranteed through improving the quality of PU Strip.

• 품질경영학회지
• /
• 제49권3호
• /
• pp.255-268
• /
• 2021

Purpose: We sought to understand why a high-speed rotating projectile featuring a fuze-and-body assembly sometimes exhibited airburst, and we intended to improve the flight stability by eliminating airburst. Methods: We performed characteristic factor analysis, structural mechanics modeling, and dynamic modeling and simulation; and we scheduled firing tests to discover the cause of airburst. We used a step-by-step procedure to analyze the reliability function for selecting the bonding force standard that prevents airburst. Results: The 00MM high-speed rotating projectile features a fuze bonded to a body assembly; the bonding sometimes can break on firing. The resulting contact force, vibration and roll damping during flight generated yaw. Flight became unstable; fuze operation triggered an airburst. Our reliability test improved the bonding force standard (the force was increased). When the bonding force was at least the minimum required, a firing test revealed that airburst/flight instability disappeared. Conclusion: Analysis and identification of the causes of flight instability and airburst render military training safer and enhance combat power. Ammunition must perform as designed. Our method can be used to set standards that improve the performances of similar types of ammunition.

• 한국군사과학기술학회지
• /
• 제24권2호
• /
• pp.228-236
• /
• 2021

In order to understand the underwater noise source factor of the linear pump type forced ejection system, a reduced-model compressed water experiment device was developed. The reduced-model compressed water experiment device consists of a reverberation tank, a linear pump type forced ejection device, and an underwater vehicle. The underwater noise source was selected from the hydraulic ram moving speed, the hydraulic ram/piston pipe spacing, the ejection pipe inlet/water ram area ratio, and the number of water ram inlets. The underwater vehicle was ejected into the reverberation tank by the device. The source level was derived from the measured sound pressure. The source level tends to increase as the hydraulic ram/piston tube spacing and the hydraulic ram moving speed increase. The source level tended to increase as the area ratio was increased, but the level was weak. The number of water ram inlet did not affect the source level.

• Journal of Applied Biological Chemistry
• /
• 제64권4호
• /
• pp.447-451
• /
• 2021

In this study, we discovered for the first time that linarin, a flavonoid compound, enhances melanin biosynthesis in B16F10 cells, and subsequently elucidated the underlying mechanism of linarin-induced melanogenesis. Linarin showed no cytotoxicity at a concentration of 42 μM and significantly increased intracellular tyrosinase activity and melanin content in B16F10 cells. Mechanistic analysis showed that linarin increased the expression of tyrosinase, tyrosinase-related protein 1 (TRP-1), and microphthalmia-associated transcription factor (MITF) that are related to melanogenesis. Moreover, linarin decreased the phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (AKT). Finally, we evaluated the effect of the structure-activity relationship of linarin and its aglycone on melanogenesis. The results indicated that linarin enhances the expression of melanogenic proteins by activating MITF expression via the modulation of mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and protein kinase B signaling pathways in B16F10 cells, thereby enhancing melanogenesis.

• 한국군사과학기술학회지
• /
• 제24권6호
• /
• pp.577-590
• /
• 2021

In this paper, we theoretically analyzed the self-alignment/navigation performance in the accelerometer resonance state generated by dither motion of ring laser gyroscope in LINS and verified it through simulation. As a result of analysis, it is confirmed that the amplitude of the accelerometer measurement amplified in the accelerometer resonance state is decreased in the process of sampling per the navigation calculation period and that frequency is changed by the aliasing effect too. It was also analysed that the attitude error in self-alignment is determined by the amplitude/frequency of the accelerometer measurement, the gain of the self-alignment loop, and the velocity and position error in the navigation is determined by the amplitude/frequency/phase error of the accelerometer measurement. This analysis and simulation results show that the self-alignment and navigation performance is not be degraded only when the amplification factor of the accelerometer measurement in the accelerometer resonance state is 3 or less

• 한국추진공학회지
• /
• 제26권4호
• /
• pp.44-53
• /
• 2022

추력조절이 가능한 고체추진기관에서 감압률은 추력중단 성능에 가장 큰 영향을 미치는 인자이다. 본 연구에서는 몇 종류의 추진기관에서 구현 가능한 감압률의 범위를 파악하였으며 이를 통하여 추진기관 감압률에 미치는 주요 인자를 도출하였다. 추진제에 대한 소화특성 파악뿐만 아니라 추진기관의 목표성능을 만족할 수 있는 감압률을 파악하는 것이 실제 추력조절 시스템 설계에 중요하며 본 연구에서와 같은 감압률 모델획득 방법론은 추력중단이 필요한 고체추진기관 설계에 적용 가능할 것으로 판단된다.

• 한국안전학회지
• /
• 제38권6호
• /
• pp.36-49
• /
• 2023

Since the recently established obligation to implement safety and health measures for specialized workers as outlined in the Occupational Safety and Health Act (OSHA) for nine occupations in January 2020 and five occupations in November 2021, there is a need to verify and inspect the on-site operation of related systems. After a comprehensive fact-finding survey and risk factor analysis, it is necessary to examine the responsibility for on-site safety and preventive measures, along with the roles and responsibilities of specialized workers. Stakeholder analysis is essential to identify the fundamental problems related to the responsibility stipulated in the purpose of OSHA and to explore the entity responsible for implementing safety measures. Therefore, in this paper, we discuss the topic of implementation based on legal standards for on-site safety and preventive measures. Additionally, we develop a role model for appropriate safety measures, outlining the dynamic relationship between those who provide labor and those who provide labor in the context of specialized workers.

• 디지털산업정보학회논문지
• /
• 제20권3호
• /
• pp.85-99
• /
• 2024

In this study, as part of an effort to help North Korean defectors adapt to South Korean society in the era of digital transformation, we attempted to analyze factors that affect North Korean defectors' satisfaction with self-employed tax agency services. The research method was analyzed using exploratory factor analysis and structural equation techniques using the LISREL statistical package. The research results are summarized as follows. First, the factors affecting the satisfaction of North Korean defector self-employed tax agency service users were identified as tax accountant characteristics and user characteristics. Second, for self-employed North Korean defectors in South Korean society, improving user characteristics is important in the initial settlement stage, strengthening tax accountant characteristics along with user characteristics is important in the mid-term settlement stage, and only strengthening tax accountant characteristics is significant in the long term. These research results are interpreted as having a great influence on the lifestyle and culture of North Korean society where North Korean defectors lived.

• Safety and Health at Work
• /
• 제7권4호
• /
• pp.389-393
• /
• 2016

Job hazard analyses were conducted to assess exposure to musculoskeletal disorder (MSD) risk factors in seven workers of three dry-cleaning establishments. In accordance with the Washington State Ergonomics Rule, the analyses were performed in two separate steps: (1) observation and checklist approaches were made to identify a "caution zone job" in the seven workers' pressing operations across the three shops; and (2) detailed posture and motion analyses were undertaken to determine a "MSD hazard" in one worker's operation using a video technique. One "caution zone job" was identified and it was the pressing operation job in which five physical risk factors were found in the pressing operations. The detailed analyses confirmed that one "MSD hazard", i.e., awkward posture in shoulders, was prevalent in the pressing operations of the three dry-cleaning facilities. It would be desirable to reduce MSD risk factors including awkward shoulder posture in the dry-cleaning industry.

• 품질경영학회지
• /
• 제46권3호
• /
• pp.397-410
• /
• 2018

Purpose: A main aims to classify quality attributes for quality assurance activities of military supplies by company size, and to derive the necessity for business improvement by company size to improve customer satisfaction through customer satisfaction coeffiecient and PCSI Index. Methods: Through a survey of defense and general businesses located in Busan and South Gyeongsang Province, the quality of service elements are classified and the client satisfaction factor and PCSI is calculated for the quality assurance activities. Results: Determine the current level of customer satisfaction with the quality of the Defence quality assurance service and present operational factors that need improvement by size of the company. Conclusion: The attractive quality of service factors for quality assurance work were in common and different and the need for improvement was identified based on differences in PCSI Index by Company size.