• Geophysics and Geophysical Exploration
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• v.25 no.2
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• pp.59-70
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• 2022

Recent studies demonstrate that machine learning has expanded in the field of seismic interpretation. Many convolutional neural networks have been developed for seismic sequence identification, which is important for seismic interpretation. However, expense and time limitations indicate that there is insufficient data available to provide a sufficient dataset to train supervised machine learning programs to identify seismic sequences. In this study, patch division and data augmentation are applied to mitigate this lack of data. Furthermore, to obtain spatial information that could be lost during patch division, an artificial channel is added to the original data to indicate depth. Seismic sequence identification is performed using a U-Net network and the Netherlands F3 block dataset from the dGB Open Seismic Repository, which offers datasets for machine learning, and the predicted results are evaluated. The results show that patch-based U-Net seismic sequence identification is improved by data augmentation and the addition of an artificial channel.

• Journal of Korea Entertainment Industry Association
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• v.13 no.2
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• pp.13-25
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• 2019

This study conducted individual in-depth interviews of tourists from Taiwan, Hong Kong and Thailand who visited Daegu. According to the analysis, Taiwan's target audience conducted an interview at the Chimac Festival in July 2018 at Duryu Park and was a university student as an individual female tourist. She got the information through SNS. The accommodation was guest house and medium and low cost hotel. The main tourist attractions included Seomun Market Night Market, Eworld and Dongseongno. The meals were Anjirang Gopchang and Galbijim in Dongin-dong. Next, the Hong Kong tourist interview was held in May 2018 at the Kwandeung Festival in Duryu Park, and was an individual tourist as a man. Lastly, an interview with a Thai tourist was held in April 2018 at the Donghwa Temple Cherry Blossom Festival in Palgongsan Mountain, and he purchased a travel agent product as a man. Participants of the tour in Daegu were interested in unusual experiences such as beauty, wedding, theme parks, and restaurants that are unique to Korea. What was disappointing was that there were not enough shopping facilities, such as duty free shops, and that the table in the restaurant was inconvenient, and that there were not enough signboards by language for foreigners.

• Geophysics and Geophysical Exploration
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• v.10 no.3
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• pp.203-210
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• 2007

As a part of basic studies on monitoring of landslides and slope stability using SP measurements, micro-electric potentials of rock samples were measured accompanied with the rock failure by a uniaxial loading test were measured. The measurement system consists of a 8 channel A/D converter with 24 bit resolution, uniaxial loading tester, strain gages and 4 sets of electrode attached to a rock sample. Rock samples of granite, limestone, and sandstone were tested. Also, mortar samples were tested in order to monitor electric-potentials of a uniform sample. Micro-electric potentials were detected in all saturated samples and the strength of them increased as the loading force increased. Sandstone samples showed the largest strength of micro-electric potential and it followed limestone and granite samples, which indicates a positive relationship with porosity of rocks. The mechanism generating these micro-electric potential can be explained in terms of electro-kinetics. In case of dry samples, micro-electric potential could be observed only in sandstone samples, where piezoelectric effect played main role due to high contents of quartz in sandstone samples. We found that biggest micro-electric potentials were observed at the electrodes near the crack surface of rock samples. This is very encouraging result that SP monitoring can be applied to predicting landsliding or to estimate collapsing position combining with monitoring of acoustic emissions.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.4
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• pp.242-248
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• 2001

A high resolution Chirp seismic profile and a multichannel seismic reflection profile were analysed to study the possibility of gas hydrate presence in the southwestern upper slope of the Ulleung Basin. The Chirp profile shows acoustic turbidity, acoustic void, and pockmarks, suggesting the presence of shallow gas in the sediments .Slope failures appear to have occurred in association with decomposition of gas hydrated sediments. A bottom-simulating reflector (BSR) is seen in subbottom depths of 60 to 110 m below the seafloor at water depths of 750 to 1130 m. The sediments above BSR are characterized by acoustic blanking probably due to amplitude reduction caused by a mixture of gas hydrate with sediments. The interval velocity above the BSR is 1,650 m/sec and it drops abruptly to 1,080 m/sec below the BSR. The sediment column between seafloor and the BSR thins with increasing water depth, which is very closely related to increasing geothermal gradient with increasing water depth in the Ulleung Basin.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.558-565
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• 2013

In this paper, modeling and simulation for performance analysis of high resolution SAR system has been carried out in the time, frequency and numeric domain using ADS Ptolemy simulation tool of Agilent corporation. SAR system consists of antenna, controller and transceiver. Error parameters affecting SAR system performances have been defined, modeled and simulated such as phase noise of frequency synthesizer, amplitude and phase characteristic of TWTA, sampling frequency of waveform generator and I/Q imbalance. Finally, the development requirements of SAR system based on the impulse response function have been derived.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2141-2145
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• 2015

A new broadcasting signal transmission, which can save its channel bandwidth using compressive sensing(CS), is proposed in this paper. A new compression technique, which uses two dimensional discrete wavelet transform technique, is proposed to get high sparsity of multimedia image. A L1 minimization technique based on orthogonal matching pursuit is also introduced in order to reconstruct the compressed multimedia image. The CS enables us to save the channel bandwidth of wired and wireless broadcasting signal because various transmitted data are compressed using it. A $256{\times}256$ gray-scale image with compression rato of 20 %, which is sampled by 10 Gs/s, was transmitted to an optical receiver through 20-km optical transmission and then was reconstructed successfully using L1 minimization (bit error rate of $10^{-12}$ at the received optical power of -12.2 dB).

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.587-598
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• 2005

KBS and ETRI have co-developed an advanced DOCR(Digital On Channel Repeater) which has an equalization and pre-distortion function and can be operated properly under lower isolation of reception and transmission antennas. Field tests of the DOCR were performed twice in Suwon area in 2004 and 2005. This paper summarizes the characteristics of the DOCR system and field test results in Suwon. The changes in DOCR coverage according to the different generations of ATSC DTV receivers were also analyzed. Basic concept to apply the DOCR system in DTV broadcasting networks in Korea is suggested through test results.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2463-2472
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• 2000

In this paper, we consider pits and falls of V oIP service scheme over the air link environment. It results that V oIP over packet switching is a more attractive approach in several points. We point out the ffilIior requirements for successful V oIP service over the air. Also, we propose V oIP CP concept for efficient wireless channel utilization. Additionally, we analyze and evaluate the performance. According to the results, It shows that the long cycle VolP vocoder CODEC such as ITU-T G.723 is better than short cycle V oIP vocoder CODEC. In this case, the increase of the simultaneous user of system is almost 60% larger than conventional circuit switching.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.9
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• pp.11-23
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• 2000

Multicarrier DS-CDMA is an effective approach to realize wideband CDMA system in a multipath fading channel. In this paper, we propose a convolutionally-coded overlapped multicarrier DS-CDMA system, and analyze the performance with subband overlapping variation to determine the overlapping percentage showing best performance. Given a total number of subcarriers M*R, we will show that the BER variation is highly dependent on the rolloff factor P of raised-cosine chip wave-shaping filter irrespective of convolutional encoding rate I/M and repetition coding rate 1/R. We also analyze the possibility of reduction in total MUI by considering both variation of a rolloff factor (0 ($\beta$ :1) and variation of subband overlapping factor (0 ( A :2), and show that the proposed system may outperform the multicarrier DS-CDMA system in [1, 12].

• Proceedings of the Technology Innovation Conference
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• 2004.06a
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• pp.214-236
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• 2004

최근 국제 금융시장은 컴퓨터 및 통신분야의 기술진보로 비 은행금융기관에서도 상업은행에 의해서만 독점적으로 제공되었던 거래서비스를 결합한 새로운 금융서비스를 제공할 수 있게 되었고, 이는 곧 은행과 비 은행금융기관의 벽을 무너뜨리는 양자 간 동질화 현상을 유도하였으며 활발한 금융 겸업화 현상으로 금융혁신이라고 부를 만한 서비스분야의 기술혁신 성과를 거두게 되었다. 본 연구는 금융권간 판매채널 통합의 시작이라 평가되는 방카슈랑스를 중심으로 금융기관 간 겸업의 활성화를 통해 산업 간 동질화를 이루는 시점에서 금융혁신이 이루어진다고 설정, 금융서비스의 기술혁신 성과를 예측해 보았다 이를 위해 먼저 우리나라 대표 금융기관 격인 은행과 보험, 증권회사가 금융겸업을 이루는 경우 각 겸업 주체 기관의 혁신적인 성과를 실증 분석하도록 한다. 분석대상은 표본기간 중 국내 주식시장에 연속으로 상장되어 있는 모든 은행, 증권, 손해보험 49개를 대상으로 수행하였으며, 표본자료는 KIS-LINE이 제공하는 재무제표자료와 한국증권거래소에서 제공하는 주가데이터에서 추출하였다. 본 연구의 금융혁신 성과 분석은 두 단계로 이루어진다. 먼저 금융기관 간 가상 합병을 이용, 시뮬레이션 분석을 하고 그 결과 각 금융기관의 ROA와 자기자본비율 및 안전성(위험성지표)을 분석한다 다음 단계로 안전성이 보장되지 않는 경우 적정하게 추정된 안전성 내에서 경영 성과를 이루는 최적 기간에 대해 실물옵션평가(Real Option Valuation) 분석을 한다. 그 결과 금융겸업을 통한 혁신 성과는 은행 주체로 비 은행금융기관과 겸영하는 경우 이상적으로 잘 보여지며, 증권 주체로 보험업을 겸업하는 경우는 ROA 와 자기자본비율 면에서는 혁신적이나 안전성 면에서는 저해된다는 결과를 알아내었다. 그리고 이 같은 안전성의 위험은 증권업을 실행하는데 요구되는 수준의 안전성을 유지하는 경우 3 년간의 투자기간 후에는 혁신사업으로 발전할 수 있는 발판을 마련하게 된다고 추정하였다.