• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1830-1835
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• 2017

8200 Series Electric Locomotives are mostly imported from overseas due to aging and uncertainty of source technology, and it's the maintenance cost is increasing. We are analyzed life cycle costs based on international standards such as IEC 60300-3-3 and IEC62278. The main conversion system of the 8200 series electric locomotive is closely related to vehicle operation and is one of the subsystems requiring frequent maintenance. In this paper, the life cycle cost of the main conversion unit in 8200 series electric locomotive is analyzed based on the maintenance manual. As a result of analysis, maintenance cost of GTO module and control device is relatively high, and it is confirmed that the cost increases according to the useful life.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.3
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• pp.135-142
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• 2017

As PED(Personal Electronic Device) market has been rapidly grown, the demand on Lithium battery, which is most commonly used power source of PED, also has been increased. Dew to this trend, the amount of Lithium battery air transportation is also increasing. However, it should be treated very carefully because Lithium is one of very explosive metal. So ICAO, IATA and civil aviation agencies try to enhance the safety of Lithium battery air transportation by aircraft certification and operating regulations. To enhance in-flight safety, the aircraft for transporting Lithium battery should equip certified fire extinguishing system. But recent studies find that Halon, currently used extinguishing agent, is not effective on extinguishing Lithium battery fire. Besides, there is no certified Halon replacement for air use and no acceptable specific minimum performance standard(MPS) for Lithium battery fire. For this issue, a study on characteristics and establishing MPS of Lithium battery fire is needed for safe air transportation of Lithium battery.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.2
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• pp.204-209
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• 2016

The analyses on self-heating effect in 7 nm node non-rectangular Bulk FinFET device were performed using 3D device simulation with consideration to contact via and pad. From self-heating effect simulation, the position where the maximum lattice temperature occurs in Bulk FinFET device was investigated. Through the comparison of thermal resistance at each node, main heat transfer path in Bulk FinFET device can be determined. Self-heating effect with device parameter and operation temperature was also analyzed and compared. In addition, the impact of interconnects which are connected between the device on self-heating effect was investigated.

• International Journal of Fluid Machinery and Systems
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• v.7 no.1
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• pp.1-6
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• 2014

The propellant acquisition vane (PAV) is a key part of a vane type surface tension propellant management device (PMD), which can manage the propellant effectively. In the present paper, the fluid transportation behaviors for five PAVs with different sections were investigated by using microgravity drop tower test. Further, numerical simulation for the propellant flow in a PMD under microgravity condition was also carried out based on VOF model, and showed the similar flow pattern for PAVs to the experiment. It is noted that the section geometry of PAVs is one of the main factors affecting the fluid transportation behavior of PMD. PAVs with bottom length ratio of 5/6 and 1/2 have larger propellant transportation velocity. Based on the experiments, there were two stages during the process of propellant transportation under microgravity environment: liquid relocation and steady transportation stage. It is also recognized that there is a linear correlation between liquid transportation velocity and relative time's square root. Those results can not only provide a guideline for optimization of new vane type PMDs, but also are helpful for fluid control applications in space environment.

• 대한공업교육학회지
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• v.32 no.1
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• pp.117-133
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• 2007

The purpose of this study was to develop the force measuring device of learning wind tunnel, teaching-learning materials in order to enhance understanding of flight principle and give interest about aviation technology in secondary school. The content of this study was consisted of the development and experiment of force measuring device for learning wind tunnel. The main results of this study were as follows: This device developed here is simple structure applying lever principle instead of the comparatively expensive load cell used in engineering college or a aviation research institute and so on. Measurement of lift and drag as well as the comparison experiment of a fluid resistance is possible with only one device developed here. The lift coefficient with angle of attack has shown the same tendency in both of theoretical and experimental values. And the stall phenomenon was found under the larger angle of attack of experimental rather than expected theoretical values. The drag coefficient with angle of attack has shown the same tendency in both of theoretical and experimental values. And drag coefficient the rate of increasement of the experimental values increased more gently than its theoretical values.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.3
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• pp.205-213
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• 2021

Due to the advantage of reducing the voltage applied to the switch semiconductor, the input series and output parallel combination is widely used in systems with high input voltage and large output current. On the other hand, the LLC converter is widely used as a high-efficiency power converter, and when connected by ISOP combination, there is a possibility that input voltage imbalance may occur due to a mismatch of passive devices. To avoid damaging the switching device, this study analyzed the DC-link voltage imbalance of a high-capacity supply using an ISOP LLC converter. In addition, the case where DC-link unbalance control was applied and the case not applied was analyzed respectively. Based on this analysis, an initial start-up algorithm was proposed to prevent input power semiconductor device damage due to DC-link over-voltage. The effectiveness of the proposed algorithm has been verified through simulations and experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.688-694
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• 2018

The transition section of the overhead rigid conductor rail (ORCR) consists of a direct induction device and a limit point to prevent the power supply failure and failure of the electric railway vehicle pantograph due to the difference of the uplift in the catenary line. In T-Bar transition section, a twin simple catenary is mostly installed between the overhead catenary system (OCS) in the ground section and the ORCR in the underground section. In this paper, we compare and analyze the possibility of replacing the twin simple catenary with heavy simple catenary. The reliability of numerical analysis results was confirmed by comparing field test with numerical results. Comparing the numerical results of the twin simple catenary with the heavy simple catenary in the transition section, the difference uplift is 5.9[mm] on average. When applying heavy simple catenary instead of twin simple catenary, the slight difference of uplift can be compensated by adjusting the height of hanger-ear or support bracket.

• The Korean Journal of Emergency Medical Services
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• v.26 no.1
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• pp.87-99
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• 2022

Purpose: This study aimed to provide basic data for the improvement of the standards related to the performance improvement of the firefighting equipment standards for special ambulances. Methods: Among the domestic firefighting equipment standards, the special ambulance standard was compared with the NFPA 1917 standard for the United States automobile ambulance 2019 and European Union European standard EN 1789 medical vehicle and its equipment, a road ambulance. Results: Anti-skid performance based on indoor noise standards, performance standards for interior lights, seat belt warning device, child car seat fixing device, safety handle, auxiliary footrest, and flooring materials should be supplemented. Conclusion: It is necessary to strengthen the production and performance standards for improvement to a level corresponding to the national standards, such as the United States and European Union.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.535-538
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• 2012

Recently active research for ITS(Intelligent Transportation System) helps to build for next generation traffic information system at information society. Build the system for sensing a vehicle speed and traffic information on the road. Provide collected data to driver, flow of overall traffic impacts have a good influence. In this study, research for building the platform and development algorithm that provided from other source processing real-time traffic data provides a more reliable real-time traffic data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1642-1646
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• 2011

In this paper, A Design of 2.45GHz and GPS antenna Integrated Board using Container security Device(ConTracer) for container cargo transportation is proposed and experimentally evaluate. Integrated antenna board include 2.4GHz chip and Ceramic GPS antenna is also consider the impact of RF interference based on simulation for applied to steel container. After a careful comparison and analysis a part of the container door for its best performance, We conduct tests to characterize. The proposed integrated antenna board is suitable for container cargo transportation application in steel container field.