• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.425-435
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• 2016

This paper describes a spread-spectrum clock generation method by utilizing a ${\Delta}{\Sigma}$ digital PLL (DPLL) which is solely based on binary phase detection and does not require a linear time-to-digital converter (TDC) or other linear digital-to-time converter (DTC) circuitry. A 1-bit high-order ${\Delta}{\Sigma}$ modulator and a hybrid finite-impulse response (FIR) filter are employed to mitigate the phase-folding problem caused by the nonlinearity of the bang-bang phase detector (BBPD). The ${\Delta}{\Sigma}$ DPLL employs a two-point modulation technique to further enhance linearity at the turning point of a triangular modulation profile. We also show that the two-point modulation is useful for the BBPLL to improve the spread-spectrum performance by suppressing the frequency deviation at the input of the BBPD, thus reducing the peak phase deviation. Based on the proposed architecture, a 3.2 GHz spread-spectrum clock generator (SSCG) is implemented in 65 nm CMOS. Experimental results show that the proposed SSCG achieves peak power reductions of 18.5 dB and 11 dB with 10 kHz and 100 kHz resolution bandwidths respectively, consuming 6.34 mW from a 1 V supply.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.11
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• pp.1288-1296
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• 2012

A candidate hybrid satellite and terrestrial network architecture, MSS/ATC(Mobile Satellite Service/Ancillary Terrestrial Component), is proposed for utilizing efficiently the exist MSS bands. Studies on the adjacent channel interference from the existing terrestrial mobile services and MSS/ATC itself are important to allocate a new ATC service frequency in MSS band. In this paper, we have analyzed the minimum permission power of terrestrial base station and the capacity loss with parameters of ACIR, number of MS(mobile Station) and MES(Mobile Earth Station) in uplink, and also, the capacity performance based on 1 beam and 1 cell assumption for MSS/ATC in downlink. The ACIR requirements are estimated in two MSS/ATC frequency allocation scenarios for 5 MHz and 10 MHz guard band to share spectrum with adjacent systems, and according to these ACIR requirements the service coverage and the receiver filter for ATC system should be designed in near future.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.2
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• pp.106-112
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• 2017

In the paper, we propose a levitation and a propulsion controller for the magnetic levitation logistic transportation system. The levitation controller is designed considering the mutual influence of the electromagnets to minimize roll and pitch movements. In order to solve the structural disadvantages of the magnetic levitation transportation system, we improve the problem of the existing controller by applying the exponential filter to the reference input. DSP-based control hardware is developed and the levitation control method is verified by levitation experiments to the air gap goal. The propulsion controller uses the space vector voltage modulation method. The propulsion controller is designed to follow the position and velocity profile by detecting the absolute position from the bar code information attached to the rail. The position control result shows satisfactory performance through the propulsion control reciprocating motion experiment.

• Journal of IKEEE
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• v.9 no.1 s.16
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• pp.40-46
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• 2005

A process variation compensation method called 'regulated drain detection' is proposed. This paper also shows the how this newly invented method is applied to a typical differential PLL. The proposed RDD(regulated drain detection) and its PLL application has been designed and tested in a $0.18{\mu}m$ 1-poly 3-metal plain digital process so that its stable performance and higher yield can be proven. The implemented PLL aimed to the operation range of 80MHz - 240MHz and the total die size is only $0.18{\mu}m$ including the internal loop filter. The tracking jitter characteristics is measured to less than 150 peak-to-peak under l.8V supply rail.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.437-444
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• 2016

Most methods for detecting arrhythmia require pp interval, diversity of P wave morphology, but it is difficult to detect the p wave signal because of various noise types. Therefore it is necessary to use noise-free R wave. In this paper, we propose algorithm for premature contraction arrhythmia classification through ECG pattern analysis and template threshold. For this purpose, we detected R wave through the preprocessing method using morphological filter, subtractive operation method. Also, we developed algorithm to classify premature contraction wave pattern using weighted average, premature ventricular contraction(PVC) and atrial premature contraction(APC) through template threshold for R wave amplitude. The performance of R wave detection, PVC classification is evaluated by using 6 record of MIT-BIH arrhythmia database that included over 30 PVC and APC. The achieved scores indicate the average of 99.77% in R wave detection and the rate of 94.91%, 95.76% in PVC and APC classification.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1860-1866
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• 2016

Helicopter-related collision accidents with structures mostly occur at landing, especially in a limited visibility environment, which necessitates some secondary equipment like a radar that can generate stationary clutter image. In this paper, we propose an algorithm that makes an image of stationary ground clutter in two dimensional range and azimuth angle domain. We present a mathematical model for the received signals from each clutter patch in the iso range ring and analyze their clutter and Doppler characteristics, assuming that a helicopter-borne radar has a rotational antenna. We propose a filter structure, which suppresses side lobe signal components while extracting a main lobe signal component, and suggest a solution for a problem stemmed from the filtering process. Finally, by conducting a simulation we show the performance of the suggested imaging algorithm on a two dimensional virtual scenario of the topographic clutter.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.533-541
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• 2011

This paper studies modeling of Jeju 80kV HVDC system and its controller by using PSCAD/EMTDC program. Reduced ac network is applied to verify interaction between ac network and dc system. Design parameter is applied to the converter transformer, harmonic filter and dc transmisstion line to simulate dc system. HVDC controller is divided into a rectifier controller and a inverter controller according to the converter operating mode. The inverter controller is composed of current control, voltage control and extingtion angle control. The rectifier controller is composed of current control and voltage control. Both controller has VDCOL characteristics so that current order is dependant on voltage variation. Step response, ac network single phase fault, three phase fault is simulated to verify the dynamic performance of controller model in both transient state and steady state.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.1
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• pp.43-48
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• 2014

Usually, image deconvolution is applied as a preprocessing step in surveillance systems to reduce the effect of motion or out-of-focus blur problem. In this paper, we propose a blind-image deconvolution filtering approach based on genetic programming (GP). A numerical expression is developed using GP process for image restoration which optimally combines and exploits dependencies among features of the blurred image. In order to develop such function, first, a set of feature vectors is formed by considering a small neighborhood around each pixel. At second stage, the estimator is trained and developed through GP process that automatically selects and combines the useful feature information under a fitness criterion. The developed function is then applied to estimate the image pixel intensity of the degraded image. The performance of developed function is estimated using various degraded image sequences. Our comparative analysis highlights the effectiveness of the proposed filter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.6
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• pp.476-481
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• 2014

In this paper, we design the pre-equalizer of transmitter circuit in order to enhancement modulation bandwidth of white LED which is light source of VLC (Visible Light Communication). Also, we eliminate yellow light component by optical filtering which mitigate frequency response of white LED. Power loss by optical filtering is overcome by using convex lens. By applying proposed system, 3 dB bandwidth deciding modulation bandwidth of white LED increases from 3 MHz to more than 25 MHz and the transmission distance increases by optical design which secure additional signal power. We optically modulate NRZ-OOK signal to LED and receive light signal using APD. We analyze received data using CSA and RFSA. As a result, we experimently demonstrate the possibility that transmits NRZ-OOK signal up to 30 Mbps in 4.5 m, 50 Mbps in 1.5 m through the pre-equalizer and optical design.

• Spatial Information Research
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• v.19 no.1
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• pp.117-126
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• 2011

Recently, AR applications provide location-based spatial information by GPS. Also, the spatial information is displayed by the angle of the camera. So far, traditional spatial indexes in spatial database field retrieve and filter spatial information by the minimum bounding rectangle (MBR) algorithm.(ex. R-tree) MBR strategy is a useful technique in the geographic information systems and location based services. But MBR technique doesn't reflect the characteristics of spatial queries in AR. Spatial queries of AR applications have high possibility of the dead space area between MBRs of non-leaf node and query area. We propose triangle node filtering algorithm that improved efficiency of spatial retrieval used the triangle node filtering techniques by exclusion the dead space. In this paper, the proposed algorithm has been implemented on PostgreSQL/PostGIS. Experimental results show the spatial retrieval that using the proposed algorithm better performance than the spatial retrieval that of the minimum bounding rectangle algorithm.