• Journal of Korean Society for Quality Management
• /
• v.51 no.2
• /
• pp.297-313
• /
• 2023

Purpose: The purpose of this study is to investigate the causes of shifting errors reported in military tracked vehicles and to improve related quality to prevent recurrence. Methods: A systematic disassembly and inspection of the transmission is carried out and an experimental simulation is conducted to reproduce the shifting error phenomenon. Electrical characteristic tests are subsequently performed and microscopic observation is also carried out on the disassembled connector parts such as pins and fractured surfaces. Results: Oil contamination and swelling deformation are observed in the connector to the vehicle due to oil leakage of its counterpart connector to the transmission. This causes electrical contact failure between both connectors in the fastened state, and it is found that shifting error of the tracked vehicle could occur subsequently. To prevent the recurrence of this phenomenon, comprehensive quality improvement is conducted including product improvement of the wiring harness assembly and strengthening activities for quality control and preventive maintenance. Conclusion: This study is expected to be helpful as a prior case study for cause analysis and recurrence prevention in the event of similar cases in the future.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.6
• /
• pp.482-490
• /
• 2023

With the advent of the Fourth Industrial Revolution, many companies are developing Smart Ships to enable autonomous navigation, unmanned operation, and cost-effective shipping. In order to facilitate the operation of these Smart Ships, significant emphasis is being placed on improving external communication capabilities and developing autonomous navigation systems. Moreover, unmanned ship operation necessitates replacing of all visually observed conditions with sensors, leading to an inevitable increase in the number of sensors and actuators compared to traditional methods. However, in South Korea, the communication network for sensors and actuators primarily relies on the conventional 1:1 hardwired wiring, with the use of higher-level communication networks when necessary. Therefore, in this paper, we introduce the AS-Interface protocol, which is used for monitoring and controlling sensors and actuators, with the expectation that it will greatly contribute to the development of future Smart Ships by reducing production time, costs, and maintenance duration.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2023.11a
• /
• pp.957-958
• /
• 2023

본 연구에서는 공정 내 인체 끼임 사고 및 저출산 고령화 시대 등의 문제들로 인한 인력 감소 문제들을 해결하기 위하여 인공지능 기반의 모빌리티 플랫폼을 개발하였다. 본 플랫폼은 yolo-v4 기반으로 로봇이 공정 내부를 이동하면서 공정 내 불량 와이어를 검출하여 공정 유지보수 관리자에게 알려 주고 실시간으로 공정 내부 상황을 무선으로 모니터링할 수 있는 기술을 연구하였다. 또한, 로봇에는 무선 충전 기능을 갖추고 있어 추가적인 공정 내 인체 끼임 사고 등을 예방할 수 있도록 하였다. 본 연구 결과에서는 불량 와이어 검출 시, 평균 92.1%의 정확도를 보였으며, 공정 제품에 대한 양품, 불량품의 검출은 평균 98%의 정확도를 보였다. 또한, 실시간 무선 영상 모니터링는 24fps로 전송되어 공정 내부를 살피는 것에 유의미한 결과를 보였다.

• Journal of Korean Medicine Rehabilitation
• /
• v.34 no.2
• /
• pp.173-180
• /
• 2024

Objectives The purpose of this study is to report the effects of Korean medicine treatment on tibia, fibula, and patellar fractures with sequelae of poliomyelitis. Methods A 64-year-old male patient was treated with acupuncture, herbal medicine, cupping, moxibustion, and exercise treatment for 59 days after open reduction and internal fixation and tension band wiring surgery. The effects were evaluated using a visual analog scale (VAS), manual muscle testing (MMT), range of motion (ROM), Western Ontario and McMaster Universities (WOMAC), and EuroQol-5 dimension (EQ-5D) index. Results After treatment, VAS decreased from 7 to 2. MMT, ROM, WOMAC, EQ-5D and walking ability were improved. Conclusions This case study suggests that Korean medicine treatment could be effective for tibia, fibula, patellar fractures in patients with sequelae of poliomyelitis.

• Journal of the Korean Society of Safety
• /
• v.39 no.2
• /
• pp.22-27
• /
• 2024

The purpose of this study is to explore the trend in insulation resistance values according to temperature and overcurrent by conducting an investigation on the actual condition and experiments on the electrical wiring during the melting furnace process. In addition, the Arrhenius equation is used to determine whether temperatures in the furnace operating process can be applied to the actual field. In the investigation of the actual condition, the insulation resistance started to decrease seven years after replacement, even though cables in oil pump A were replaced in 2010. Both the experimental and theoretical values of the insulation resistance obtained using the Arrhenius equation decreased with an increase in temperature. Errors in insulation resistance (MΩ) values between tests and the Arrhenius equation ranged from ±2 to ±10, demonstrating a high similarity. Results revealed that when the insulation resistance cannot be measured in a manufacturing workplace (quarterly analysis), it can be estimated by partially applying the Arrhenius equation.

• Journal of the Korean Society of Safety
• /
• v.39 no.1
• /
• pp.16-26
• /
• 2024

This study aims to introduce a method for risk assessment analysis aimed at preventing electrical fires within the manufacturing industry. Initially, we provided a functional block diagram illustrating the electrical equipment employed in various processes within a food manufacturing company in Chungcheongbuk-do. Subsequently, we categorized the components of each machine outlined in the functional block diagram and determined the priority of failure for each classified component. Upon implementing the model in the frying process of the food manufacturing company, specific components, including MC, motor, mixer heater, electric wiring, and terminal block, exhibit a risk priority number (RPN) of 40 or higher. This identified an electrical issue within the manufacturing process and environment. Consequently, we propose a methodology to identify latent failure modes that could escalate into fires or systemic issues if not promptly addressed. It is essential to note that while the FMEA presented in this study may not immediately impact food manufacturing, its applicability extends to various workplaces.

• International journal of advanced smart convergence
• /
• v.13 no.3
• /
• pp.321-327
• /
• 2024

In recent years, the frequency of fires in college dormitories has been increasing, primarily due to outdated electrical wiring and improper use of electrical appliances. Given the high population density in such buildings, fires can cause significant damage to life and property. To better understand the dynamics of dormitory fires, this study uses Pyrosim fire simulation software to model fire scenarios in a six-story male dormitory. The study focuses on analyzing key factors such as heat release rates, smoke spread, temperature changes, and carbon monoxide concentrations during a fire. Simulation results indicate that smoke spreads rapidly after a fire breaks out, significantly reducing visibility and hindering evacuation efforts. Simultaneously, temperatures near the fire source rise quickly, exceeding safe levels, and carbon monoxide concentrations reach dangerous thresholds in a short time, greatly increasing the risk of poisoning. Based on these findings, the study proposes several recommendations to improve fire prevention in dormitories, including installing smoke barriers, improving evacuation routes, adding mechanical smoke extraction systems, and enhancing students' fire safety awareness and skills through regular training. These measures are crucial for reducing fire risks and enhancing fire safety in college dormitories.

• Advances in materials Research
• /
• v.13 no.5
• /
• pp.375-389
• /
• 2024

Installing wiring or plumbing fixtures necessitates creating chases within masonry walls, which, while serving practical purposes, raises a crucial concern regarding the potential compromise of the masonry's structural integrity. Given these concerns, it becomes essential to thoroughly understand the impact of incorporating chases on masonry strength. In this study, 37 AAC masonry prisms (200×330×100 mm³) were cast and tested for compression. The prisms were equipped with chases of various depths -10 mm, 20 mm and 30 mm; and orientations (horizontal, inclined, and vertical), which were then filled with mortar using 1:2, 1:4, and 1:6 cement-to-sand ratios. The primary objectives were to assess the strength decrease in the prisms with different chase characteristics compared to a control specimen and to determine the percentage strength increase due to filling materials compared to unfilled chases. Key findings indicate that as chase depth increases, there is a substantial reduction in prism strength. However, the orientation of the chase does not significantly affect strength reduction. Importantly, filling the chases with mortar leads to a significant increase in prism strength. This study not only unveils the complex impact of chase characteristics on masonry strength but also emphasizes the crucial role of filling materials in strengthening these prisms.

• Archives of Metallurgy and Materials
• /
• v.66 no.3
• /
• pp.795-798
• /
• 2021

Molybdenum (Mo) is used to form a barrier layer for metal wiring in displays or semiconductor devices. Recently, researches have been continuously attempted to fabricate Mo sputtering targets through additive manufacturing. In this study, spherical Mo powders with an average particle size of about 37 um were manufactured by electrode induction melting gas atomization. Subsequently, Mo layer with a thickness of 0.25 mm was formed by direct energy deposition in which the scan speed was set as a variable. According to the change of the scan speed, pores or cracks were found in the Mo deposition layer. Mo layer deposited with scan speed of 600 mm/min has the hardness value of 324 Hv with a porosity of approximately 2%. We demonstrated that Mo layers with higher relative density and hardness can be formed with less effort through direct energy deposition compared to the conventional powder metallurgy.

• Journal of Korean Society of Steel Construction
• /
• v.12 no.5 s.48
• /
• pp.595-604
• /
• 2000

Web openings of large beams provide space for wiring, piping, and duct work to provide for proper drainage, pipes and duct must be slightly sloped with the attendant result that all web openings can not be centered on the centroidal axes of the beams. Test specimens are made for opening-depth to beam-depth ratio of 0.5 and for eccentricities of the opening center line of 10% from middepth of the beam because of the proximity of the opening edge to the flange. In this paper, available test results and theories relating to the strength of composite beams having eccentric rectangular openings are surveyed and experiments were carried out to examine the structural behaviors. In all the tests in this paper good agreement is demonstrated with maximum loads measured in tests, and observed failure modes Furthermore, compared with analytical values and experimental values of interaction diagram between moment and shear capacity were safed as it is scattered with outer part of the analytical values.