• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.88-93
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• 2010

In this paper, an edge detecting sensor using ultrasonic detection module is developed which will be used for areas of industrial applications such as plastic film winding system, cloth winding system, paper roll industry, etc. The developed sensor have properties that more exactly detect the edge line, that less affected by environmental noise, and that it produced more stable measurement output. The mass of the winding object is dominantly affect the dynamics of the system and it could produce undesirable result of the system such as stability of the closed-loop system and accuracy of edge-line-following-control(ELFC) objective. Also, there exist sensor noise due to the mechanical vibration or other environmental effect. These noise also degrade the efficiency of control system. In order to compensate these problems, this paper present a fuzzy PI/PID edge-line-controller, and which is designed and implemented.

• Analytical Science and Technology
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• v.15 no.5
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• pp.399-409
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• 2002

A system software on-line spectral analysis of atomic emission spectrometer. The system program consisted of a control part for the optical instruments and the spectrum analysis part the artificial intelligence method to reduce nonlinear error of the wavelengths. McPHERSON 207 Monochromator controlled GPIB communication protocol, and the detector signal was measured from PMT by using A/D Amplifier that was made by Photon_Tek. co.. HNN(Hybrid Neural Network) of artificial intelligence technique was applied to the qualitative analysis of P, Cu, Fe, Cr, and that was accurately applied to the quantitative analysis of Cd with 10 ppb level better than the conventional methods.

• The Journal of the Korea Contents Association
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• v.7 no.11
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• pp.84-93
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• 2007

This paper presents a methodology that accelerates estimating the system-level power consumption for on-chip bus of SoC platforms. The proposed power modeling can estimate the power consumption according to the change of a target SoC system. The proposed model comprises two parts: the one is power estimation of bus logics reflecting the architecture of the bus such as the number of bus layers, the other is to estimate the power consumed by the bus lines during data transmission. We designed the target multimedia SoC system, MPEG encoder as an example and evaluated power consumption using this model. The simulation result shows that the accuracy of the proposed model is over 92%. Thus, the proposed power model can be used to design of a high-performance/low-power multimedia SoC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7C
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• pp.669-677
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• 2003

A new Modem technique - 8SQAM(8-state Superposed Quadrature Amplitude Modulation) - for use in power and bandwidth limited digital communication system is proposed. 8SQAM is free of inter-symbol interference(ISI) and generates output signals which have a smooth and continuous phase transition and a reduced envelope fluctuation by keeping correlation between amplitudes and phases of two subsequent symbols. Accordingly, 8SQAM, as compared with a conventional 8PSK, is influenced a little by ISI and inter-modulation(IM) caused by nonlinear distortions. In this paper, the performance of the 8SQAM system, in a nonlinearly amplified channel impaired by additive white Gaussian noise(AWGN), ISI and IM, is analyzed via computer simulation. The simulation result shows that 8SQAM outperforms 8PSK with roll-off value of $\alpha$=0.25 by 2.5dB in CNR to maintain BER=1$\times$10$^{-4}$ when input back-off(IBO) of HPA is 3dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6C
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• pp.530-538
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• 2010

In this paper, estimation methods of cell searching and DoA (Direction of Arrival) for mobile relay stations with a uniform linear array are proposed. The proposed methods can improve the performance of cell searching and DoA estimation by removing the effect of STOs when there exist symbol timing offsets (STOs) between the signals received from adjacent base stations,. Also, the proposed methods can improve the performance of DoA estimation significantly when there exists Doppler frequency shift caused by movement of the mobile relay station. The performances and computational complexities of the proposed cell searching and DoA methods are evaluated by computer simulation under Mobile WiMAX environments.

• Journal of the Korea Society of Computer and Information
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• v.16 no.8
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• pp.129-135
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• 2011

In this paper, we propose a multi target's elevation angle estimation method using multi beam forming technique. This method make a stacked beam to digital processing a received signal in array element. There can be desired receiving beam to application weight value at antenna element in beam forming. Currently, we are to make multi stacked beam using fast fourier transform in stead of phase shifter to be a computer performance much improvement. Also, we improve multi beam directivity using beam steering error correction technique in order to beam steering to desired direction in receiver. Through simulation, we show that the proposed elevation estimation method based on fast fourier transform and beam steering error correction technique, improves th performance of target estimation compared to previous method.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.8
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• pp.54-61
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• 1999

This paper proposes a new optic link structure applicable to broad-band wireless access microcellularsystem servicing in the millimeter wave frequency band. The proposed structure utilizes photonic mixing by exploiting the nonlinear property of EOMs, which leads to the frequency up-conversion at the CS and thus, electrical mixing at a BS is not required. Moreover, via transmitting an additional optical millimeter wave carrier into the Bs, the dispenses with an active optic source, which miniaturizes the BS. We analyze CNR, IM3/C in the downlink and SFDR in the uplink. Through simulation using the typical parameter values we also show the feasibility of the proposed system based on the requirements in the current microcellular system.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.4
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• pp.247-252
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• 2009

This paper presents an Integer-N phase-locked loop (PLL) frequency synthesizer using a novel prescaler based on a charge pump and clock triggering circuit. A quadrature VCO has been designed for the 900MHz UHF RFID application. In this circuit, a voltage-controlled oscillator(VCO), a novel Prescaler, phase frequency detector(PFD), charge pump(CP), and analog lock detector(ALD) have been integrated with 0.35-${\mu}m$CMOS process. The integer divider has been developed with a verilog-HDL module, and the PLL mixed mode simulation has been performed with Spectre-Verilog co-simulator. The sweep range of VCO is designed from 828 to 960 MHz and the VCO generates four phase quadrature signals. The simulation results show that the phase noise of VCO is -102dBc/Hz at 100 KHz offset frequency, and the maximum lock-in time is about 4us with 32MHz step change (from 896 to 928 MHz).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.1
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• pp.84-92
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• 2000

A GaAs MESFET MMIC transmitter for 2.4 GHz wireless local loop handset is designed and fabricated. The transmitter consists of a double balanced active mixer and a two stage driver amplifier with voltage negative feedback. In particular, a pair of CS-CG(common source-common gate) structure compensates the reduction in dynamic range caused by unbalanced complementary IF input signals. And to suppress the leakage local power at RF port, the mixer is designed by using phase characteristic between the ports of MESFET. At the bias condition of 2.7 V and 55.2 mA, the fabricated MMIC transmitter with chip dimensions of $0.75\times1.75 mm^2$ obtains a measured conversion gain of 38.6 dB, output $P_{idB}$ of 11.6 dBm, and IMD3 at -5 dBm RF output power of -31.3 dBc. This transmitter is well suited for WLL handset.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7A
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• pp.668-675
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• 2002

This paper proposes pre-distorter combined LUT with 2ιpartition interpolation method to reduce nonlinear distortion which was caused by high PAPR and to update LUT quickly. Pre-distorted gain and phase can be found by using LUT which consisted of AM/AM and AM/PM value, and OFDM signal amplitude. The proposed 2ιpartition interpolation can accurately find predistorted gain and phase using bit shift and add component instead of increasing size of LUT which requires increasing the amount of computation. The performance of the proposed method was measured by the difference between HPA input and output characteristics by the LUT size, constellation, SER performance by the HPA, and LUT update error by the HPA characteristic changes. As a result, it is shown that when the size of the LUT is 32 and 64 for 16-QAM and 64-QAM, nonlinear distortion nearly didn't occurred.