• Journal of Positioning, Navigation, and Timing
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• v.10 no.3
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• pp.229-234
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• 2021

In this paper, a study was conducted on the power amplifier control required to design an eLoran transmitter system using a low-height antenna. The eLoran transmitter developed during the eLoran technology development project conducted in Korea used a small 35 m antenna due to the difficulty of securing a site for antenna installation. This antenna height is very low compared to the height of 750 m which is required for eLoran 100 kHz signal transmission without any radiation loss. In the case of using such a small antenna, not only the radiation efficiency of the transmission is lowered, but also the power module control must be performed more precisely in order to transmit the eLoran standard signal. The equivalent RLC circuit of the transmitter system was implemented and transient analysis was conducted to derive the input required voltage for satisfying the output requirement. The voltage waveform was also generated by the RLC circuit analysis to generate the eLoran signal. Furthermore, we suggest power width modulation method to control eLoran power amplifier module more sophisticatedly.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.3
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• pp.130-135
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• 2012

In this paper, we propose a technique to detect the size and location of the small target in images by using Gaussian kernel repeatedly. In order to detect the size and location of the small target, we find the local maximum value by applying the facet model and then use the $3{\times}3$ Gaussian kernel repeatedly. we determine the size of small target by comparing the local maximum value $D_2$ according to the number of iteration. To reduce the computational complexity, we use the Gaussian pyramid when using the kernel repeatedly. Through the experiment, we verified that the size and location of the small target is detected by the number of iterations and results show improvements from conventional methods.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1500-1505
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• 2004

This paper presents the design and control of a small Brushless DC (BLDC) Motor for entertainment robots. In order to control the developed BLDC motor, Adaptive Fuzzy Control (AFC) scheme via Parallel distributed Compensation(PDC) is developed for the multi- input/multi-output plant model represented by the Takagi-Sugeno(TS) model. The alternative AFC scheme is proposed to provide asymptotic tracking of a reference signal for the systems with uncertain or slowly time-varying parameters. The developed control law and adaptive law guarantee the boundedness of all signals in the closed-loop system. In addition, the plant state tracks the state of the reference model asymptotically with time for any bounded reference input signal. The suggested design technique is applied to the velocity control of a developed small BLDC motor for entertainment robots.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.1033-1036
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• 1998

In this research project, two aspects of small signal stability are studied: improvement in Hessenberg method to compute the dominant electromechanical oscillation modes and siting FACTS devices to damp the low frequency oscillation. Fourier transform of transient stability simulation results identifies the frequencies of the dominant oscillation modes accurately. Inverse transformation of the state matrix with complex shift equal to the angular speed determined by Fourier transform enhances the ability of Hessenberg method to compute the dominant modes with good selectivity and small size of Hessenberg matrix. Any specified convergence tolerance is achieved using the iterative scheme of Hessenberg method. Siting FACTS devices such as SVC, STACOM, TCSC, TCPR and UPFC has been studied using the eigen-sensitivity theory of augmented matrix. Application results of the improved Hessenberg method and eigen-sensitivity to New England 10-machine 39-bus and KEPCO systems are presented.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.112-115
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• 2001

Eigenvalue perturbation theory of augmented system matrix(AMEP) is a useful tool in the analysis and design of large scale power systems. This paper describes the application results of AMEP algorithm with respect to all controller parameter of KEPCO systems. AMEP for interarea and local mode can be used for turning controller parameter, and verifying system data and linear model of controller.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.685-688
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• 1998

In this research project, two aspects of small signal stability are studied: improvement in Hessenberg method to compute the dominant electromechanical oscillation modes and siting FACTS devices to damp the low frequency oscillation. Fourier transform of transient stability simulation results identifies the frequencies of the dominant oscillation modes accurately. Inverse transformation of the state matrix with complex shift equal to the angular speed determined by Fourier transform enhances the ability of Hessenberg method to compute the dominant modes with good selectivity and small size of Hessenberg matrix. Any specified convergence tolerance is achieved using the iterative scheme of Hessenberg method. Siting FACTS devices such as SVC, STACOM, TCSC, TCPR and UPFC has been studied using the eigen-sensitivity theory of augmented matrix. Application results of the improved Hessenberg method and eigen-sensitivity to New England 10-machine 39-bus and KEPCO systems are presented.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.365-368
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• 1998

In this research project two aspects of small signal stability are studied: improvement in Hessenberg method to compute the dominant electromechanical oscillation modes and siting FACTS devices to damp the low frequency oscillation. Fourier transform of transient stability simulation results identifies the frequencies of the dominant oscillation modes accurately. Inverse transformation of the state matrix with complex shift equal to the angular speed determined by Fourier transform enhances the ability of Hessenberg method to compute the dominant modes with good selectivity and small size of Hessenberg matrix. Any specified convergence tolerance is achieved using the iterative scheme of Hessenberg method. Siting FACTS devices such as SVC, STACOM, TCSC, TCPR and UPFC has been studied using the eigen-sensitivity theory of augmented matrix. Application results of the improved Hessenberg method and eigen-sensitivity to New England 10-machine 39-bus and KEPCO systems are presented.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.400-403
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• 2003

This paper presents the signal processing of the panoramic thermal warning system that detects the small target such as aircraft and helicopter from afar. We develope the all round looking thermal imaging system which can scan all the way. This system acquires the panoramic images to reconstruct the IR images by revolving head of sensor typed line sensor at high speed. For detection, where the object of interest may be small, it is sometimes difficult to specify from object and background by conventional contrast enhancement methods. Therefore we use the adaptive plateau equalization algorithm each region to improve the contrast and make the hardware system which consists of the signal processing board for real-time display. We can verify the proposed method by the computer simulation and the hardware implementation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.7
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• pp.1000-1003
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• 2021

In this paper, we investigate how to track illegal drones by using communication signal received from illegal drones, which is a promising candidate position tracking scheme for anti-drone systems, and is particularly effective in tracking small illegal drones in urban areas. We propose an enhanced tracking scheme using multiple antennas to improve the performance of tracking by reducing the error of position tracking. In the proposed tracking scheme, a tracker is equipped with four receive antennas that are evenly spaced 90 degrees apart, and received signal strength indicators (RSSIs) received by four receive antennas are pre-averaged before being used to calculate the distance between tracker and target. Our numerical results show that the proposed scheme outperforms the conventional scheme in terms of accuracy.

• Mass Spectrometry Letters
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• v.15 no.1
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• pp.26-39
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• 2024

Gold nanostructures (Au NSs) are useful and interesting matrices for mass spectrometric analysis of various biomolecules based on organic matrix-free laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS). Au NSs provide high efficiency and versatility in LDI-TOF-MS analysis based on their well-established synthesis and surface functionalization, large surface area, high laser absorption capacity, and photothermal conversion efficiency. Therefore, Au NSs based LDI-TOF-MS can be a facile, functional, and efficient analytical method for important small biomolecules owing to its simple preparation, rapid analysis, salt-tolerance, signal reproducibility, and quantitative analysis. This review chronologically summarizes the important advance of Au NSs-based LDI-TOF-MS platforms in terms of in-depth mechanism, signal enhancement, quantitative analysis, and disease diagnosis.