• Journal of Power Electronics
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• v.16 no.3
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• pp.1056-1066
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• 2016

Wireless power transfer (WPT) technology is now recognized as an efficient means of transferring power without physical contact. However, frequency detuning will greatly reduce the transmission power and efficiency of a WPT system. To overcome the difficulties associated with the traditional frequency-tracking methods, this paper proposes a Direct Phase Control (DPC) approach, based on the Second-Order Generalized Integrator Phase-Locked Loop (SOGI-PLL), to provide accurate frequency-tracking for WPT systems. The DPC determines the phase difference between the output voltage and current of the inverter in WPT systems, and the SOGI-PLL provides the phase of the resonant current for dynamically adjusting the output voltage frequency of the inverter. Further, the stability of this control method is analyzed using the linear system theory. The performance of the proposed frequency-tracking method is investigated under various operating conditions. Simulation and experimental results convincingly demonstrate that the proposed technique will track the quasi-resonant frequency automatically, and that the ZVS operation can be achieved.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.409-412
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• 2001

In this paper, we designed Tracking Filter in using frequency hopping system, which can acquire hopping pattern in very short time and track it in the bandwidth of 231 MHz - 292 MHz. This is the RF filter with a high Q value and its center frequency is adjustable through digital signal.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1673-1675
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• 1996

We have studied the effect of surface tension and flow rate of contaminants, wettability, frequency of applied voltage dependence of tracking breakdown. As the flow rate of contaminant is increasd, the surface resistivity is decreased, and the leakage current is increased, the time to tracking breakdown is decreased. It is found that time to tracking breakdown depends on the frequency of contaminant, that is difference of wettability. And as the frequency of applied voltage is increased, time to tracking breakdown decreased.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.700-702
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• 2016

The Doppler Radar that mounted on Electro Optical Tracking System has been operated to measure range and velocity during the initial mission of space launch vehicle at Naro space center. In this paper, we mentioned configuration of MFCW(Multi frequency Continuous Wave) and FMCW(Frequency Modulation Continuous Wave) Doppler Radar on Electro Optical Tracking System and described method of range measurement.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.205-208
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• 2000

In this paper, we design Tracking Filter that is principal component of Frequency Hopping System. This filter can acquire hopping pattern in short time and track it at high speed. This is high Q, narrowband, RF filter whose center frequency is controlled digitally between 30MHz ∼ 88MHz.

• Electrical & Electronic Materials
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• v.10 no.8
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• pp.770-777
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• 1997

Some polymer materials including epoxy resin are being instead of porcelain for outdoor insulating materials such as insulators bushings cable terminators and surge arrester housing. And the largest problem to be overcomed is the tracking and erosion of the outdoor polymer material brought about by dry band arcing during prolonged exposure to contaminations. In this paper the effect of surface tension wettability flow rate of contaminants with varying surfactant content and frequency of applied voltage on the tracking breakdown of epoxy insulating materials were investigated. As the flow rate of contaminant is increased the surface resistivity is decreased and the leakage current is increased the time to tracking breakdown is decreased. It is found that time to tracking breakdown depends on the surface tension of contaminant that is difference of wettability. And as the frequency of applied voltage is increased time to tracking breakdown decreased.

• Smart Structures and Systems
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• v.14 no.6
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• pp.1197-1220
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• 2014

Accurate actuator tracking is critical to achieve reliable real-time hybrid simulation results for earthquake engineering research. The frequency-domain evaluation approach provides an innovative way for more quantitative post-simulation evaluation of actuator tracking errors compared with existing time domain based techniques. Utilizing the Fast Fourier Transform the approach analyzes the actuator error in terms of amplitude and phrase errors. Existing application of the approach requires using the complete length of the experimental data. To improve the computational efficiency, two techniques including data decimation and frequency decimation are analyzed to reduce the amount of data involved in the frequency-domain evaluation. The presented study aims to enhance the computational efficiency of the approach in order to utilize it for future on-line actuator tracking evaluation. Both computational simulation and laboratory experimental results are analyzed and recommendations on the two decimation factors are provided based on the findings from this study.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.140-146
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• 2005

In this paper, we proposed the frequency offset compensation algorithm and tracking algorithm which could improve the accumulated phase error for HDR-WPAN system. The proposed frequency offset compensation technique estimated each sample phase error by autocorrelation characteristics of CAZAC sequence, estimated phase error multiple each sample in a symbol, and finally compensated for the frequency offset. After frequency offset compensation using two steps, coarse and fine frequency offset, tracking algorithm have to use to compensate for the accumulated phase error. Because there is no pilot symbol in payload, more phase rotation occurred in received signal constellations due to the accumulated phase error as the payload length increase. Tracking algorithm compensates for a cumulative phase error ${\theta}$ between payload data.

• Korean Institute of Interior Design Journal
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• v.22 no.6
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• pp.212-219
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• 2013

This study uses a fashion shop facade design to track human gaze, find gaze frequency for gaze time for the gaze points along the path of sight, and expose the importance of facade design and figure out the value through theoretical systematization. Thus, this study employed the measurement method in physiological psychology which is sight-tracking device with eye-tracking to perform effective data evaluation. To find gaze frequency and study the contents to reflect on the facade, precedent study review, and case study of facade design to collect stimulants to be used in eye-tracking experiment were executed. And the eye-tracking experiment which traces the movement of eye[pupil] was performed. As the result of analyzing gaze frequency, The characteristics of such gaze path formation made the characteristics for gaze frequency even clearer. What was characteristic in the analysis result according to 'average value for gaze time' was that only 8 out of 2000 areas showed over 1 second of frequency and, and all other shoed less than 1 second of gaze time. This indicates that human sight endlessly jumps around, and that it 'Stay' where it has interest. This study found the average of the frequency of this 'Stay' in facade design. This study well presents the major points to add value to the design of the space of facade based on scientific measurement/analysis data obtained through visual understanding. Through such, this study is thought to be able to have a positive interaction with marketing by forming a theoretical background bringing utility to purchase environment and assisting in sales increase.

• Korean Institute of Interior Design Journal
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• v.19 no.4
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• pp.82-89
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• 2010

The studies published up to now, related to the correlation between spatial structure and visitors' behavior in a museum are rather relatively lacking when it comes to the in-depth consideration for the effect of the actual exhibition environment. So the main purpose of this study is to define the correlation between the light environment and the visitors' behavior. Towards this end, this study uses 'space syntax' to quantify the spatial structure with 'integration', 'connectivity' and 'control value'. Meanwhile, 'tracking score' and 'tracking frequency' were selected as the scope among the indices of behavior's analysis. The results of this study are as follows; First, integration and correlation of tracking score and tracking frequency are lowest when it comes to the extra large historical museums where the difference of intensity of illumination by each convex space. Meanwhile, the most considerable effect is exerted by control value. Compared to tracking score, tracking frequency is closely related to 'syntactic variables'. Second, visitors do not take the short cut the dark exhibition space even when very dark exhibition spaces continue after passing through relatively bright space. Analysis of visitors' behavior by control value in the exhibition space composed of this type of intensity of illumination environment is not valid. Third, visitors move to relatively brighter transitional space compared to the exhibition space with low intensity of illumination when passing through dark exhibition continually. Meanwhile, when visitors pass through the exhibition space there is some difference intensity of illumination they move to relatively dark exhibition center among the subsequent exhibition spaces. Accordingly, when the composition of exhibition space that continues onto the environment of low intensity of illumination is inevitable, differentiating intensity of illumination appropriately would be effective in inducing visit to the subsequent exhibition space.