• Geophysics and Geophysical Exploration
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• v.27 no.2
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• pp.91-107
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• 2024

Single-channel seismic exploration has proven effective in delineating subsurface geological structures using small-scale survey systems. The seismic data acquired through zero- or near-offset methods directly capture subsurface features along the vertical axis, facilitating the construction of corresponding seismic sections. However, substantial noise in single-channel seismic data hampers precise interpretation because of the low signal-to-noise ratio. This study introduces a novel approach that integrate noise reduction and signal enhancement via matrix rank optimization to address this issue. Unlike conventional rank-reduction methods, which retain selected singular values to mitigate random noise, our method optimizes the entire singular value spectrum, thus effectively tackling both random and erratic noises commonly found in environments with low signal-to-noise ratio. Additionally, to enhance the horizontal continuity of seismic events and mitigate signal loss during noise reduction, we introduced an adaptive weighting factor computed from the eigenimage of the seismic section. To access the robustness of the proposed method, we conducted numerical experiments using single-channel Sparker seismic data from the Chukchi Plateau in the Arctic Ocean. The results demonstrated that the seismic sections had significantly improved signal-to-noise ratios and minimal signal loss. These advancements hold promise for enhancing single-channel and high-resolution seismic surveys and aiding in the identification of marine development and submarine geological hazards in domestic coastal areas.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.95-101
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• 2007

Recently, two phase scheme for removing impulse noise in images is proposed. This algorithms first detect the noise candidates based on the adaptive median filter, and then apply optimizing techniques recursively only to those noise candidates to restore image. Thus the noise detector with high accuracy is important role on this algorithm, In this paper, novel noise detector is proposed, which can detect impose noise with high accuracy while reducing the probability of false detecting image details as impulses. And the method for reducing computational cost of regularization phase is presented also.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.133-135
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• 2001

UMTS QoS는 [1]에 정의되어 있는 바와 같이 계층적 구조를 가지고 있다. 즉, 단-대-단 QoS를 위해서는 UMTS QoS의 보장 뿐만 아니라 여러 계층에서의 QoS가 동시에 보장되어야 한다. 즉. UMTS 단일 입장에서 QoS를 보장하기 위해서는 인터넷 서비스 보장 기법과 UMTS QoS 보장 기법간의 변환 기법이 필수적이라 할 수 있다. 현재 winsock2에서는 QoS 보장을 위한 다양한 API가 새롭게 정의되어 있다. 이러한 API는 이동 단말기에 탑재될 것이므로 이 API에서 정의하는 QoS 파라미터와 UMTS망에서 사용되는 QoS 파라미터와의 변환 기법이 필요하게 된다. 본 논문은 UMTS QoS의 계어 측면에서 요구되는 변환기를 구성하는데 필요한 변환 메커니즘을 제안한다. 본 메커니즘은 외부 망과 독립적으로 구성된 UMTS QoS 모델과 Internet QoS 모델로으 변환을 통하여 단-대-단 QoS를 보장하는데 그 목적이 있다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.165-166
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• 2014

기존 LED(Light Emitting Diode) 전류 제어용 SSPR(Secondary Side Post Regulator) 스위치를 갖는 구조의 다중출력 컨버터는 LED 정 전류 제어를 위한 별도의 부스트 컨버터 없이 전류제어가 가능하여 원가 및 부피 저감과 효율이 상승하는 장점이 있다. 하지만, 주 출력단(Master)의 피드백을 받아 1차 측 메인 스위치를 제어하게 되어 제어 회로가 복잡하고 주 출력단 부하 변동에 의해 부 출력단(Slave)의 크로스-레귤레이션(Cross-Regulation) 특성이 좋지 않은 단점이 있다. 따라서, 본 논문에서는 기존 SSPR 스위치의 장점을 갖고 주 출력 단의 부하 변동에도 부 출력단의 크로스-레귤레이션 특성이 좋은 새로운 직렬 공진형 LED 구동회로를 제안한다. 최종적으로 제안 회로를 4채널 LED 구동회로에 적용하여 그 실험결과를 바탕으로 제안 회로의 타당성을 검증하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.509-512
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• 2008

The lining concrete of water tunnel is a much capability to occur crack due to drying shrinkage and vibrator compaction etc. Because of crack of concrete induce structural problem and decrease durability of concrete, it is need to reduce crack of concrete. In this an Analytical study to analyze the effect of curing of concrete and compaction on the lining concrete. As the results, it was found that control of construction condition into curing of concrete and compaction improve on construction efficiency of the lining concrete.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.2
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• pp.181-195
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• 2010

The policy of industrial complexes (innovative clusters) is being changed to build the linkage structure within Mega Economic Region according to the national policy of Mega Economic Region. The aim of this analysis is to draw the hypothetical linkage structure of industrial complexes in the internal and external Capital Region. First, with the survey data of firms located in the industrial complexes, we can catch the regional linkages of firms in the local area and internal and external Mega Economic Region. Next, the measure of structural similarity between industrial complexes is calculated with the number of employees by industrial sectors. After considering the geographical distance between industrial complexes, the percentage of industrial sectors and the location quotient synthetically, the idea of hub-and-spoke type linkage structure between clusters is deduced.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.177-179
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• 2002

A1$_2$ $O_3$기판재료의 $K_{IC}$ 증가를 위한 재료설계를 시도하였다. 먼저 A1$_2$ $O_3$기판을 구성하는 A1$_2$ $O_3$다층구조물에 적절한 다공성 중간층을 삽입하는 샌드위치 구조물을 제조하였다. 제조된 A1$_2$ $O_3$구조물의 미세구조를 관찰하였고, Vickers 경도와 three-point bending test를 통해서 단일조성 구조물과 샌드위치 구조물의 경도와 인성 측정치를 비교하였다. 다공층을 삽입한 A1$_2$ $O_3$샌드위치 구조물의 Single-Edge Notched Beam이 단일 조성의 구조물에 비해 파괴강도와 인성이 향상되는 결과를 얻었다.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.587-588
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• 2008

Digital PLL을 위한 높은 해상도를 갖는 TDC(Time to Digital Converter)를 $0.18{\mu}m$ CMOS 공정으로 설계하였다. 2단 구조를 갖는 TDC를 제안하였고 이를 Cadence Spectre를 이용하여 검증하였다. TDC는 Difference pulse generator, coarse 변환기와 fine 변환기로 구성된다. 그리고, 2단 변환기와 Thermometer decoder를 이용하여 delay cell의 수를 적게 유지하면서도 높은 해상도를 얻을 수 있었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.830-838
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• 2003

In this paper, TX/RX dual operation microstrip single antenna for satellite communication is designed, analyzed, fabricated and measured. TX/RX frequency ranges are 14.0∼l4.5 GHz, 11.7∼12.75 GHz in respectively and vertical and horizontal polarizations are used for TX and RX. This antenna uses microstrip direct feeding for RX and aperture coupled strip-line feeding for TX and accommodates stacked elements for a high directivity and wide impedance bandwidth. In an analysis of single element, FDTD and MOM was compared and FDTD analysis was more accurate because of the consideration of finite structure and imperfect two ground planes. The proposed structure facilitates generally to an extension of two dimensional array and lower an unwanted radiation by strip-line feed in TX. TX/RX 8${\times}$4 array has a return loss below -10 dB, -14 dB in TX, RX respectively and a gain ranging from 19.1∼20.7 dB in TX, 21.2∼21.8 dB in RX which has a radiation efficiency of 43∼5l %, 52∼57 %.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.2
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• pp.35-44
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• 1995

In this paper, the single E-plane structure which is inserted in the slot of waveguide tube for good yield has been proposed and analyzed by the variational method. A CAD program for designing of the narrow-band waveguide bandpass filters has been developed by the passband correction method with filter synthesis theory. Using the developed CAD program, 0.02dB equi-ripple Chebyshev type 5-section bandpass filter is designed at the center frequency of 3.82GHz, fabricated with tunable structure. The experimental results show good agreements with the theoretical results.