• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.101-108
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• 2023

Although the proportion of coal-fired power generation is decreasing, efficient operating technology is needed to continuously invest in facilities and reduce maintenance costs until it is abolished. Boilers, one of the main facilities of power plants, operate for a long time in harsh environments of high temperature and high pressure. In addition, damage due to deterioration is likely to occur depending on the fuel and tube material used. It is very important to judge soundness because damage caused by deterioration adversely affects facility operation. Previously, replication method was used to analyze the progress of deterioration. In the replication method, pre-treatment such as chemical treatment is performed on the boiler tube in the field, the area is reproduced by attaching a film, and the replicated film is determined by an expert in the laboratory with an expensive microscope. However, this method involves substantial costs and time requirements, as well as the possibility of human errors. To address these issues, we developed a mobile health assessment system in this research. Since it is detachable and takes images in real time, this system enables swift evaluations across a broad range and facilitates the assessment of preprocessing quality. In addition, it was intended to reduce existing human mistakes by developing a degradation classification algorithm using the merger cluster method.

• 한국전기화학회:학술대회논문집
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• 2000.04a
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• pp.57-57
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• 2000

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1998.10a
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• pp.323-328
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• 1998

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.1138-1139
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• 2005

• Journal of Drive and Control
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• v.12 no.4
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• pp.71-76
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• 2015

The therapy of injecting a fixed amount of a prescribed drug for a predetermined time is an effective treatment in relieving pain during anticancer treatments. Due to recent medical technology development, cancer is currently classified as a disease that can be managed in the patient's lifetime. If patients were able to use a drug delivery system that was portable, sustainable and had an accurate flow control, they would be able to inject medication whenever they need. In this study we developed a piezoelectric micropump for a drug delivery system by designing a pump chamber, check valve and diaphragm. We also developed a driving circuit that consumes low power and to which we applied a variety of signals. We fabricated a portable drug delivery system with this piezoelectric micropump and driving circuit. In addition, through a performance test, we confirmed that the system can precisely control the drug flow rate.

• Journal of Appropriate Technology
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• v.5 no.1
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• pp.33-37
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• 2019

One of main problems in developing electricity grid for archipelago country like Indonesia is the geographical concerns as it consists of many islands. In some rural areas, electricity has not been available yet due to the limited infrastructure access, leading to high investment cost. In this study, a portable energy storage system based on the lithium-ion batteries called Tabung Listrik or TaLis (DC-based power bank) and DC house system were proposed as the solution for providing electricity for rural areas with relatively lower cost. TaLis is designed to be portable so it is easy to carry around as well as it can be used for many purposes. Since 2017, TaLis prototype has been used as the energy storage in a DC house system at Sekolah Master Indonesia, where an array of PV rooftop is functioned as the main DC power supply. Besides, some TaLis were also dispatched for emergency response during the disaster situations in Indonesia, such as during the measles outbreak in Asmat-Papua, the earthquake disaster in Lombok and tsunami in Palu.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.199-201
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• 2007

This paper presents the installation of measuring system for the transient behaviors of grounding system impedances using portable impulse current generator. The measuring system is controller, with controller, power supply, impulse current generator and data aquisition system. In the evaluation of the impulse response in a ground electrode, the step response is calculated based on the ratio of the voltage and current observed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.328-331
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• 2001

Color simulation on a portable colorimeter was performed to distinguish quantitatively a chromaticity coordinates on a color guide of a urine strips by using the spectral power distribution of chip LED, the spectral reflectance of printed objects, and the spectral sensitivity of photodiode. The CIE tristimulus values and chromaticity coordinates realized by a colorimeter were modified to be conformable with real color reactions. Experimental results showed a real color in comparison with those obtained by Colorimeter CM2C(Color Savvy).

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.159-160
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• 2015

Recently, it is increased to use the portable device with small size. It is also increasing for demand of a small size adapter. To reduce the size of components, switching frequency has to be increased. But it causes higher switching loss and temperature of components. Especially, the temperature of adapter must be limited because adapter can be easily touched when portable device is being charged. To reduce temperature of adapter, high efficiency is essential. To solve this problem, this paper proposes design of resonance frequency optimization for LLC converter with high efficiency and low temperature of passive components.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.4
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• pp.339-345
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• 2002

This paper presents a portable power supply equipped with a battery charger. The proposed system can be operated separatedly distinguishing between DC/AC and AC/DC function. The former uses a battery and the latter a line voltage as the power source to operate on an inverter and a battery charger, respectively. To keep the output voltage being sinusoidal and to have the high dynamic performances even In the cases of load variations, a proper control method is adapted. The operational principles and analysis are explained in detail. The validity of the proposed system is proved from the experimental results.