• Journal of the Institute of Convergence Signal Processing
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• v.15 no.3
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• pp.91-96
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• 2014

For Sound source direction and separation method, Frequency Domain Binaural Model(FDBM) shows low computational cost and high performance for sound source separation. This method performs sound source orientation and separation by obtaining the Interaural Phase Difference(IPD) and Interaural Level Difference(ILD) in frequency domain. But the problem of reflection occurs in practical environment. To reduce this reflection, a method to simulate the sound localization of a direct sound, to detect the initial arriving sound, to check the direction of the sound, and to separate the sound is presented. Simulation results show that the direction is estimated to lie close within 10% from the sound source and, in the presence of the reflection, the level of the separation of the sound source is improved by higher Coherence and PESQ(Perceptual Evaluation of Speech Quality) and by lower directional damping than those of the existing FDBM. In case of no reflection, the degree of separation was low.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1820-1822
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• 2007

In this paper we fabricated a fiber device composed of cascaded long-period fiber gratings between which a birefringent erbium-doped fiber was inserted and proposed its application as a polarization-controlled interleaved signal gating fiber device. Because the core and cladding modes of the fabricated fiber device have polarization-dependent phase difference due to the birefringence of the erbium-doped fiber, its interference spectrum can be modulated by varying the input polarization.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.380-384
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• 1988

An optical device, named "T-MES", to measure the accuracy of printed scale of measuring tapes was developed. It has 11 optical sensors, that are exactly positioned every 100 mm on the 1 m frame. The sensors detect the beginning of the printed part and generate the puleses. The time difference between each signal pulse and the first sensor signal pulse is proportional to the error of printed scale. The measured data are trasmitted through a IEEE-488 interface to a IBM-AT computer and analyzed. The analysis software continuously displays the measured result on the CRT.n the CRT.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.915-921
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• 2005

Accurate and reliable tracking system is essential for the central train control system. There are two systems widely being used. one is the fixed block system which utilizes the track circuit for the detection of train position. the other is the moving block system which has the advantage over the former since it enables shorter radio signal for the train position detection. In this paper a new algorithm is proposed which uses signal's phase difference of arrival to detect the train position. Experimental verification of the algorithm is presented in the paper.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.82-85
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• 2003

This paper proposes a preprocessing method for tracking aircraft's take-off and lading. The method uses accumulative difference image technique for segmenting the object from the background, and obtains the centroid of the object exactly using centroid method. Then the moving object is analyzed and represented with the information such as feature point, velocity, and distance. A simulation result reveals that the proposed algorithm has good performance in segmenting and tracking the aircraft.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.12
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• pp.691-697
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• 2003

This paper proposes a current differential relay for transformer protection that operates in accordance with a blocking method based on the difference-function of a differential current. For magnetic inrush and over-excitation, discontinuities in the first-difference function of the differential current arise at the points of inflection, which correspond to the start and end of each saturation period of the core. These discontinuities are converted into the pulses in the second- and third-difference functions of the differential current. The magnitudes of the pulses are large enough to detect saturation of the core. A blocking signal is issued if the magnitude of the third-difference function exceeds the threshold and is maintained for three quarters of a cycle. The performance of the relay is assessed under various conditions with magnetic inrush, internal faults and external faults. The proposed blocking method can improve significantly the operating time of a relay and achieve high sensitivity of a relay.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.4
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• pp.1-6
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• 2003

In this Paper, the moving image is detected by a collision preventive system. The noise of these images is reduced by a mean filter. In case of detecting a movement with a binary difference image the moving area is detected exactly by the labeling and the projective method. When the image move slowly with the tracking mode of the system, the center of the tracking window move to the previous tracking window. And the tracking windows are divided into a tracking mode and a coasting mode which are determine by the Contrast-Difference Correlation of the date obtained from a difference image. The coasting mode determine whether continue the tracking step or not comparing the coasting-time values to reducing the error by the disturbance. The coasting and tracking of these moving images are verified by the result of the simulation.

• Journal of Astronomy and Space Sciences
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• v.27 no.1
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• pp.21-30
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• 2010

In processing space geodetic data, mapping functions are used to convert the tropospheric signal delay along the zenith direction to the line of sight direction. In this study, we compared three mapping functions by evaluating their effects on the tropospheric signal delay and position estimates in GPS data processing. The three mapping functions tested are Niell Mapping Function (NMF), Vienna Mapping Function 1 (VMF1), and Global Mapping Function (GMF). The tropospheric delay and height estimates from VMF1 and GMF are compared with the ones obtained with NMF. The differences among mapping functions show annual signals with the maximum occurring in February or August. To quantitatively estimate the discrepancies among mapping functions, we calculated the maximum difference and the amplitude using a curve fitting technique. Both the maximum difference and amplitude have high correlations with the latitude of the site. Also, the smallest difference was found around $30^{\circ}N$ and the amplitudes increase toward higher latitudes. In the height estimates, the choice of mapping function did not significantly affect the vertical velocity estimate, and the precision of height estimates was improved at most of the sites when VMF1 or GMF was used instead of NMF.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.3
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• pp.143-149
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• 2007

From the announcement which sees discusses about the spatial modulation which is a basic principle of the induction signal which the instrument landing system provides to the aircraft with instrument landing system, depth made be and became the help which makes understand and character did. Explained the fundamental notions of spatial modulation with precedence, the signal which space is modulated with this together influenced to the aircraft receiver and the azimuth and angle of glide were indicated and until with the principle of operation of the aircraft receiver and the process which is general DDM(difference in depth of modulation) and they related they explained.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.2
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• pp.194-200
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• 2003

In this paper, FSK(Frequency Shift Keying) demodulator which is widely used for FH-SS system is designed and the experimental results are analyzed. The performance of the ADPLL(All-digital Phase-Locked-Loop), which is the main part of the demodulator circuit, is analyzed by the computer program. Using Maxplus-II tool provided by altera. co., ltd, each part of the ADPLL is designed and all of them is integrated into EPM7064SLC44-10 chip. And the simulation results are compared with the characteristics of the implemented circuits for analysis. There is about 2${\mu}\textrm{s}$ difference in time constant of the PLL. This difference is not critical in the demodulator. And the experimental results show that the transmitted data is well demodulated when the phase difference between the FSK modulated signal and the reference signal is about 180 degree.