• Geophysics and Geophysical Exploration
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• v.11 no.2
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• pp.127-136
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• 2008

To identify the potential area of gas hydrate in the Ulleung Basin, 2-D and 3-D seismic surveys using R/V Tamhae II were conducted in 2005 and 2006. Seismic survey equipment consisted of navigation system, recording system, streamer cable and air-gun source. For reliable velocity analysis in a deep sea area where water depths are mostly greater than 1,000 m and the target depth is up to about 500 msec interval below the seafloor, 3-km-long streamer and 1,035 $in^3$ tuned air-gun array were used. During the survey, a suite of quality control operations including source signature analysis, 2-D brute stack, RMS noise analysis and FK analysis were performed. The source signature was calculated to verify its conformity to quality specification and the gun dropout test was carried out to examine signature changes due to a single air gun's failure. From the online quality analysis, we could conclude that the overall data quality was very good even though some seismic data were affected by swell noise, parity error, spike noise and current rip noise. Especially, by checking the result of data quality enhancement using FK filtering and missing trace restoration technique for the 3-D seismic data inevitably contaminated with current rip noises, the acquired data were accepted and the field survey could be conducted continuously. Even in survey areas where the acquired data would be unsuitable for quality specification, the marine seismic survey efficiency could be improved by showing the possibility of noise suppression through onboard data processing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.541-546
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• 2010

The push-push DRO(dielectric resonator oscillator) using a multi-layer structure of LTCC(low temperature co-fired ceramic) fabrication is designed. After the single DRO of series feedback type in the center frequency of 8GHz is designed, the push-push DRO in the center frequency of 16GHz including the Wilkinson power combiner is designed. The bias circuit affecting the size of oscillator are embedded in the intermediate layer of the LTCC multi-layer substrate. As a result, the large reduction in the size of VCO is obtained compared to the general oscillator on the single layer substrate. Experimental results show that the fundamental and third harmonics suppression are above 15dBc and 25dBc, respectively, and phase noise characteristics of the push-push DRO presents performance of -102dBc/Hz@100KHz and -128dBc/Hz@1MHz offset frequencies from carrier.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.433-438
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• 2017

Containing an Angle-of-Arrival(: AOA) estimation and interference suppression techniques, an adaptive beamformer is one of core techniques for the Signal Intelligence(: SIGINT) which collect various intelligence utilizing cutting edge devices including the radar and satellite. It generates a beam with the directivity in a corresponding direction, to efficiently receive a signal from the specific direction, using antenna array. In this paper, we present the received signal model including interference signals and noise, which can be applied to an input of the signal intelligence satellite system equipped with the AOA estimation and the interference cancellation techniques, and analysis the characteristics of various signals, which can be included in the proposed received signal model. This proposed signal model can be directly applied to the performance evaluation for a variety of beamforming techniques. Also, we verify the spectrum characteristic of the presented received signal model in the frequency domain through computer simulation examples.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.123-129
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• 2016

Disturbance Observer(DOB) based control is considered for the purpose of the balancing performance enhancement in a single-wheel robot. Design of DOB can be folded into two parts, the inverse model of the plant and the Q-filter. The inverse model is derived from the inverted stick model and a Q-filter is designed to stabilize the inverse model. In this paper, a Q31 filter is designed and its effect is evaluated by experimental studies. The time constant provides a complimentary characteristic between the disturbance suppression and the sensor noise immunity. Therefore, suitable selection of the time-constant must be considered. Comparative experiments are conducted to investigate the control performances when three different Q filters are respectively applied in the DOB. Through the analysis of the experimental results, a time constant is designed to have a proper value in the design of DOB for balancing control of a single-wheel robot.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.2
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• pp.1-13
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• 2017

In This Paper, we find the Target Candidate Region and the Location of the Candidate Region by Performing the Morphological Difference Calculation and Pixel Labeling for Robust Small Target Detection in Infrared Image with low SNR. Conventional Target Detection Methods based on Morphology Algorithms are low in Detection Accuracy due to their Vulnerability to Clutter in Infrared Images. To Address the Problem, Target Signal Enhancement and Background Clutter Suppression are Achieved Simultaneously by Combining Moravec Algorithm and LCM (Local Contrast Measure) Algorithm to Classify the Target and Noise in the Candidate Region. In Addition, the Proposed Algorithm can Efficiently Detect Multiple Targets by Solving the Problem of Limited Detection of a Single Target in the Target Detection method using the Morphology Operation and the Gaussian Distance Function Which were Developed for Real time Target Detection.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.353-358
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• 2009

For the successful development of 75 tonf class liquid rocket engine, a plenty of tests on each engine component has to be performed and this is equally true for a combustor. However the test facility which is in operation at Korea Aerospace Research Institute lacks its capacity to perform fire tests of a 75 tonf class combustor at its nominal thrust. Since the test facility has to be ready prior to the start of development tests, it is very urgent to establish the test facility. The preliminary design of a test facility for a 75 tonf class combustor which was performed according to the urgent necessity is described in the paper.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.393-400
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• 2014

In this paper, we have designed the transmitter for earth station terminal operating with military geostationary satellite on Ka-band that is complied with MIL-STD-188-164A. The designed antenna of this terminal is dual-offset gregorian reflector which is consist of corrugated horn and iris polarizer, othermode transducer. This antenna meets radiation pattern and transmit EIRP spectral density requirements in this standard. The designed RF systems of this terminal are consist of Block Up Converter(BUC) converting frequency band from IF to Ka band and SSPA having low-power consumption and compact light-weight using the pHEMT MMIC compound devices. This RF systems applied with VSWR, spurious/harmonic suppression, output flatness and phase noise requirement in this standard.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2492-2498
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• 2013

In this paper, A lane tracking algoritm is proposed for lane departure warning system. To eliminate perspective effect, input image is converted into Bird's View by inverse perspective mapping. Next, suitable features are extracted for lane detection. Using clustering and lane similarity function with noise suppression features are extracted. Finally, lane model is calculated using RANSAC and lane model is tracked using Kalman Filter. Experimental results show that the proposed algorithm can be processed within 20ms and its detection rate approximately 90% on the highway in a variety of environments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.343-351
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• 2008

In this paper, a spiral shaped common mode filter(CMF) embedded in a flexible printed circuit board(FPCB) is proposed for a multi-function cable. The CMF embedded in a FPC cable presents a new concept as a multi-function cable by the common mode rejection characteristics without a surface mounted device(SMD) CMF. The embedded CMF has a wideband common mode rejection bandwidth and an enhanced differential mode characteristics compared to conventional CMFs that use a magnetic material such as a ferrite of high loss. The proposed CMF of 3 turn inductors has a common mode rejection bandwidth from 0.4 GHz to 3.12 GHz and has 1.95 dB at 3 GHz, 6.97 dB at 8 GHz improvements of a differential mode insertion loss compared to the commercial LTCC(Low Temperature Co-fire Ceramics) CMFs.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.93-100
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• 2005

In this paper, we implement the embedded speech recognition system to support various application services such as audio and video control using speech recognition interface on cars. The embedded speech recognition system is implemented and ported in a DSP board. Because MIC type and speech codecs affect the accuracy of speech recognition. And also, we optimize the simulation and test environment to effectively remove the real noises on a car. We applied a noise suppression and feature compensation algorithm to increase an accuracy of sppech recognition on a car. And we used a context dependent tied-mixture acoustic modeling. The performance evaluation showed high accuracy of proposed system in office environment and even real car environment.