• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.121-127
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• 2016

We propose a algorithm to calculate power factor of fundamental waveform in an environment where the voltage and current have been distorted by harmonics. In the proposed power factor computation algorithm, voltage and current are converted to rotating DQ reference frame, and power factor is calculated from active power and reactive power. We compare the proposed method with the conventional power factor measurement method as mathematically. In a condition that voltage and current are distorted by harmonics, the proposed method accurately measure the power factor of fundamental wave, and it is confirmed by simulation using MATLAB. If the proposed power factor measurement method is applied to an automatic power factor control system, a power factor compensation performance can be maximized in harmonic distortion environment. As a result, it is possible to reduce electricity prices, reduce line loss, increase load capacity, ensure the transmission margin capacity, and reduce the amount of power generation.

• Journal of the Korea Society of Computer and Information
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• v.20 no.3
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• pp.97-106
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• 2015

In this paper, the development of infrared threat surrogate system is described and it can be used to verify the performance of DIRCM system. In this research, threat surrogates are manufactured using same F# and reflective optics used in 1st- and 2nd-Gen. real seeker so that the threat surrogate system can be used to develop code-based jamming techniques. Also the threat surrogate system can analyze the saturation jamming effect for image seeker using FPA detector. The result shows that 1st- and 2nd-generation threat surrogates have relatively precise tracking performance and jamming effect.

• Smart Media Journal
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• v.6 no.4
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• pp.9-16
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• 2017

The railway point machine is an especially important component that changes the traveling direction of a train. Failure of the point machine may cause a serious railway accident. Therefore, early detection of failures is important for the management of railway condition monitoring systems. In this paper, we propose a noise-robust anomaly detection method in railway condition monitoring systems using sound data. First, we extract feature vectors from the spectrogram image of sound signals and convert it into modulation feature to ensure robust performance, and lastly, use the support vector machine (SVM) as an early anomaly detector of railway point machines. By the experimental results, we confirmed that the proposed method could detect the anomaly conditions of railway point machines with acceptable accuracy even under noisy conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8901-8907
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• 2015

Conventional streetlight with the not-adjustable light distribution characteristic is generating light pollution such as glare, damage to the crops and disturbed sleep, because beam of streetlight is not distributed evenly according to the surrounding areas and road conditions. In this paper, we proposed the new structure LED streetlight controlled light irradiation angle according to the surrounding areas and road conditions. Proposed LED streetlight are available to the adjustable light distribution characteristic using the half-circle angle control device. Result of measurement and simulation, beam angle is made available to control at least from $100^{\circ}$ up to $154^{\circ}$, average illumination exceeded 15% of KS regulation and overall uniformity exceeded more than 50% of KS regulation. the Developed large capacity LED streetlight luminaire is considered to minimize glare and light pollution and optimize uniformity ratio of illuminance.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1097-1103
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• 2012

There are many fish farms being cultivated in the southwestern cost of South Korea. Because the farms cultivating use the basic method that inflow and circulate sea-water, slight negligence and bad design cause major negative impact on fish deaths. Also, the optimal temperature for each specie of fishes has already been proven to differ on each specie. Maintaining this environment, regardless of seasons, is very difficult and that requires research to develop. In this paper, basic characteristics of heat and mechanism of heat transfer are studied. Based on this, Open-end water vessel is designed and constructed using sandwich-insulation panels and simulated to store the heat in certain isolated space. This study confirmed that it is possible to keep constant temperature by this method, in large areas of water where it is insulated by heat insulator. and equipped with heater in Open-end water vessel where the other part is heated. The AC power controller maintains the constant temperature required and the temperature controller detects and displays the temperature by using the micro-processor.

• Journal of Korea Multimedia Society
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• v.14 no.7
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• pp.924-932
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• 2011

Though the spread of the touch screen devices is now revitalized, the Korean input methods in the touch screen devices are mostly the button input methods using keypads. Even though the button input methods are used with a touch screen, they still adopts the existing qwerty keyboard. It means that the existing methods can not be improved. This research suggests that the Korean input method which can be used in the portable terminals and the touch screen devices, for example, a smart phone which has a limited sized screen. It assigns every vowel a process which corresponds with the Korean invention theory and the vowel input method is to drag it. Through the mock experiments, we confirmed that the simplification of the Korean alphabet is more efficient than the existing methods, in the point of the speed of the Korean input.

• Journal of the Korean Institute of Gas
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• v.3 no.2 s.7
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• pp.53-61
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• 1999

The safety of gas utilities is intimidated by many causes. Among them, subsidence is a dominant cause to decrease the safety of gas utilities. So it is very important to monitor the displacement of subsidence. The purpose of this study is to on-line monitor the subsidence of gas utilities using Static GPS(Global Positioning System)technique. Static GPS technique, which is one of various GPS techniques and originally applied to monitor the crustal activity, was applied for two gas station in Korea Gas Corporation. Prior to applying this technique to the field, i.e, gas station, a preliminary test was peformed to confirm the accuracy of this technique. As a result, it was proved that this technique can measure the displacement of gas utilities three dimensionally by sub-millimeter. After getting confirmation of GPS technique, we applied this technique for two gas stations and monitored the amount of subsidence during 5 months. As a result of field test, we can conclude that the gas stations was subsiding several millimeters in a year.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1925-1930
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• 2010

For high-speed/high-accuracy position control of a gantry-moving-type linear motor, we propose a nonlinear adaptive controller including a synchronization algorithm. Linear motors are easily affected by force ripple, friction, and parameter variations because there is no mechanical transmission to reduce the effects of model uncertainties and external disturbances. Synchronization error is also caused by skew motion, model uncertainties, and force disturbance on each axis. Nonlinear effects such as friction and ripple force are estimated and compensated for. The synchronization algorithm is used to reduce the synchronous error of the two side pillars. The performance of the controller is evaluated via computer simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.9
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• pp.787-794
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• 2012

The visible light communication is considered as a next generation communication technology, when utilizes LED and PD for communication. Since it is easy to provide LOS communication environment along with cheap deployment cost, the positioning system based on VLC has been actively studied. However, the existing positioning system using VLC requires a complex computation and an additional deployment cost due to sensors for example. In this paper, we propose a new positioning system based on VLC which does not require additional complexity and the cost. In addition, the procedure for operating LED panels for positioning and the recognition schemes of pilot signal are proposed. The performance of recognition schemes of pilot signal is analyzed through the computer simulations.

• Journal of the Korean Data and Information Science Society
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• v.22 no.3
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• pp.371-380
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• 2011

The noise caused by a variety of reasons worsens the quality of input image when we use the images reproducing device. The basic difficulty to solve this problem is that the noise and the signal are difficult to be distinguished. Contrast enhancement such as unsharp masking is one of the most important procedures to improve the quality of input images. The conventional unsharp masking enhances the images by adding their amplified high frequency components. The noise component of the input images, however, also tends to be amplified due to the nature of the unsharp masking. This paper considers the block approach for detecting niose and image feature of the input image so that the unsharp masking could be adaptively applied accordingly. Simulation results show that it is made possible to enhance contrast of the image without boosting up the noisy components by applying the proposed algorithm.