• 대한치과보철학회:학술대회논문집
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• 2000.11a
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• pp.30-31
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• 2000

• Clinical and Experimental Pediatrics
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• v.64 no.9
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• pp.468-470
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• 2021

• The monthly packaging world
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• s.329
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• pp.80-84
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• 2020

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.3
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• pp.277-282
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• 2005

This paper describes a step-down AC voltage regulator using an AC chopper and auxiliary transformer, which is a series connected to the main input. The detail design of the AC regulator, logic and PWM pattern of the AC chopper is described and the three-phase AC regulator using two single­phase AC choppers with a three transformer configuration is proposed for three-phase application. The proposed three-phase system has the advantages of lower system cost due to reduced switch number and gate driver circuit as well as advantages of decreased size and weight because it uses a series compensated scheme. The proposed AC regulator has many benefits such as fast voltage control, high efficiency and simple control logic. Experimental results indicate that it can be used as a step-down AC voltage regulator for power saving purposes very efficiently.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.4
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• pp.62-70
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• 1995

Brushless DC Motor (BDCM) is widely used in the industry such as a variable speed motor in a compressor for room air conditioners, because the motor can be easily controlled and operated over a wide speed range. The system to drive BDCM needs encoder that senses rotor position. Gut in a certain application, the position sensor has to be avoided. In the paper, various position sensorless drive systems for BDCM are investigated and critically evaluated, so that the effective method of sensorless control can be selected. Out of these methods, the freewheeling diode current sensing has many advantages. For example, the simple starting procedure makes it possible to perform sensorless control even in low speed. So the hardware design for this method has been carried out and the system has been implemented using DSP. The experimental results verified that the freewheeling diode current sensing approach has advantages in starting procedure and low speed sensing.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.3
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• pp.122-128
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• 2012

An interleaved boost converter has many advantages such as current ripple reduction, switching effective double, etc. Due to these advantages, the interleaved boost converter applies to the power factor correction circuit. However, there are almost no analysis results because the input voltage and current are time-varying system in the power factor correction application. Therefore, in this paper, the current ripples of the power factor correction circuit using single-phase boost dc-dc converter and 2-phase interleaved boost dc-dc converter are compared and analyzed in detail. In order to verify the validity, computer simulation and experimental are performed.

• ETRI Journal
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• v.34 no.6
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• pp.847-857
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• 2012

Intrusion detection systems (IDSs) have an important effect on system defense and security. Recently, most IDS methods have used transformed features, selected features, or original features. Both feature transformation and feature selection have their advantages. Neighborhood component analysis feature transformation and genetic feature selection (NCAGAFS) is proposed in this research. NCAGAFS is based on soft computing and data mining and uses the advantages of both transformation and selection. This method transforms features via neighborhood component analysis and chooses the best features with a classifier based on a genetic feature selection method. This novel approach is verified using the KDD Cup99 dataset, demonstrating higher performances than other well-known methods under various classifiers have demonstrated.

• Structural Engineering and Mechanics
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• v.25 no.5
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• pp.577-596
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• 2007

Recent development of fiber optic sensor technology has provided an excellent choice for civil engineers for performance monitoring of civil infrastructures. Fiber optic sensors have the advantages of small dimensions, good resolution and accuracy, as well as excellent ability to transmit signal at long distances. They are also immune to electromagnetic and radio frequency interference and may incorporate a series of interrogated sensors multiplexed along a single fiber. These advantages make fiber optic sensors a better method than traditional damage detection methods and devices to some extent. This paper provides a review of recent developments in fiber optic sensor technology as well as some applications of fiber optic sensors to the performance monitoring of civil infrastructures such as buildings, bridges, pavements, dams, pipelines, tunnels, piles, etc. Existing problems of fiber optic sensors with their applications to civil structural performance monitoring are also discussed.

• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.469-478
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• 2016

This paper designs an application for detecting various objects using a smart phone with camera sensor, then implements the application that detects the number of faces in front of a user by using the Face API provided by android and generates a speech to the user. For implementing the application, the GoF strategy pattern is applied to design the application. It provides some advantages; first, the algorithm development schedule can separate the whole application development schedule; next, it makes easier to add the algorithm. For example, another detecting algorithm for the other objects (character, motion detection) that may be developed in the future, or it may be replaced by a more high-performance algorithm. With the propose method, a general smart phone can make some advantages that can provide information of various objects (such as moving people and objects, and detected character from signboards) to the person who is visually impaired.

• Convergence Security Journal
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• v.12 no.1
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• pp.49-54
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• 2012

Special applications designed for smart phone, so called "Apps" are rapidly emerging as unique and effective sources of environmental monitoring tools. Using the advantages of Information and Communication Technology (ICT), this paper propose an application that provides Indoor Gas Monitoring System. In this paper, use four wireless gas sensor modules to acquire sensors data wirelessly coupled with the advantages of existing portable smart device based on Android platform to display the real-time data from the sensor modules. Additionally, this paper adapts a simple gas classification algorithm to inform in-door Gas for users real-time based.