• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2009년도 학술논문요약집
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• pp.186-186
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• 2009

The characterization strategy of fracture networks are classified into a deterministic or statistical characterization according to the type of required information. A deterministic characterization is most efficient for a sparsely fractured system, while the statistics are sufficient for densely fractured rock. In this study, the ensemble mean and variability of the effective connectivity is systematically analyzed with various density values for different network structures of a power law size distribution. The results of high resolution Monte Carlo analyses show that statistical characteristics can be a necessary information to determine the transport properties of a fracture system when fracture density is greater than a percolation threshold. When the percolation probability (II) approaches unity with increasing fracture density, the effective connectivity of the network can be safely estimated using statistics only (sufficient condition). It is inferred from conditional simulations that deterministic information for main pathways can reduce the uncertainty in estimation of system properties when the network becomes denser. Overall results imply that most pathways need to be identified when II < 0.5 statistics are sufficient when II $\rightarrow$ 1 and statistics are necessary and the identification of main pathways can significantly reduce the uncertainty in estimation of transport properties when 0.5$\ll$1. It is suggested that the proper estimation of the percolation probability of a fracture network is a prerequisite for an appropriate conceptualization and further characterization.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제9권6호
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• pp.131-136
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• 2020

차량 환경의 통신에서 콘텐츠의 사전 캐싱은 사용자로부터 콘텐츠 서버까지의 지연시간을 감소시킬 수 있다. 하지만 어디에, 어느 량 만큼의 사전 캐싱을 해야하는 지에 대한 문제점은 아직도 해결되지 않고 있다. 본 논문에서는 차량의 이동 확률을 토대로 차량이 다음으로 이동하게 될 기지국 후보들에게 각각 최적화된 량만큼의 콘텐츠를 분산시켜 사전 캐싱하는 방안을 제시한다. 우선, 각 차량의 이동 확률은 Markov Chain을 이용하여 학습되었다. 그리고 분산하여 사전 캐싱할 콘텐츠의 량은 무선 환경을 기반으로 최적화되었다. NS-3를 기반으로 진행된 실험에서 제안방안은 기존 방안에 비하여 최소의 지연시간을 유지하며 트래픽을 가장 많이 절약한 결과가 도출되었다.

• Journal of Information Technology Applications and Management
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• 제27권5호
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• pp.69-80
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• 2020

Recently, luxury brands are selling their products to consumers using their own direct online channels. In the online channel, marketing strategy through storytelling is needed because consumers do not have enough product experience. Therefore, luxury brands are actively utilizing social media and delivering stories includes their birth and growth. Unlike mass media, social media communicates with consumers more quickly and frequently and delivers the story of brand naturally. This study classifies luxury brands into four groups based on story recognition of luxury brands and self-esteem, and analyzes and materializes each group of the propensities of luxury brand consumption. It also tries to draw strategic implications for effective SNS advertising by analyzing narrative transportation on SNS advertising, interests in videos, and the interests in story based on these typified groups of luxury consumption. The result of the analysis shows that there is a difference in consumption propensity among consumers who were classified into four groups according to story cognition of luxury brands and self-esteem. There is also a difference in the response to narrative images through SNSs, such as narrative transportation, interests in videos, and interests in brand stories.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.30-37
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• 2018

Unlike an AC system, a DC system does not cause problems with synchronization, stability, reactive power, system losses, and cost. However, more research is still required for the application of DC Systems. This paper proposes a stable black-start strategy for a stand-alone DC micro-grid, which consists of an energy storage system, photovoltaic generator, wind-turbine generator, diesel generator, and DC loads. The proposed method is very important for avoiding inrush current and transient overvoltage in the power system equipment during restoration after a blackout. PSCAD/EMTDC software was used to simulate, analyze, and verify the method, which was found to be stable and applicable for a stand-alone DC micro-grid.

• 정보처리학회논문지D
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• 제15D권4호
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• pp.531-540
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• 2008

적응적 랜덤 테스팅 (Adaptive Random Testing, ART)은 입력 도메인 내에 테스트 케이스를 넓고 고르게 분산시키는 방법을 통해 입력 도메인 내에 존재하는 오류 패턴을 순수 랜덤 테스팅 (Random Testing, RT)보다 효율적으로 찾아내기 위한 테스트 케이스 선택 기법이다. 테스트 케이스 선택에 많은 연산량을 필요로 하는 초기 ART 기법인 거리 기반 ART (Distance-based ART, D-ART)와 제한 영역 기반 ART (Restricted Random Testing, RRT)의 개선을 위해 입력 도메인을 반복 분할하는 기법들이 제안되었고, 이 기법들은 낮은 연산량 및 성능 향상등의 효과를 가져왔다. 하지만, 입력 도메인 반복 분할 기반 기법에서도 기존 ART 기법에서 나타나는 테스트 케이스 분포 불균일 문제가 존재하고, 이는 기법의 확장성에 장애 요소로 작용한다. 따라서 본 논문에서는 반복 분할 기반 기법에서 나타나는 테스트 케이스 분포의 특성을 파악하고, 이를 적정 수준으로 제어하기 위한 입력 도메인 확장 정책을 제안하였으며, 실험을 통해 2차원 입력 도메인에서 3%, 3차원 입력 도메인에서 10% 수준의 성능 향상을 확인하였다.

• 한국환경생태학회지
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• 제29권2호
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• pp.200-209
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• 2015

This study was conducted to investigate the distributional characteristics of ground beetles and to provide basis information for biodiversity management including the ground beetles in the Naejangsan National Park area. Pitfall traps were installed throughout 20 sites within Naejangsan National Park during 2008 to 2011 to collect ground beetles. A total of 2,409 collected ground beetles were identified with 35 species belonging to 19 genera of 8 subfamilies. Coptolabrus jankowskii jankowskii, Eucarabus sternbergi sternbergi, and Pterosticus audax were dominant at the core area, while Pheropsophus jessoensis, Synuchus nitidus, Synuchus cycloderus, and Chlaenius naeviger were dominant at the border of the National Park and adjacent to the road or grassland. These differences of dominant species also affected to the similarity of species composition between core and border area, and caused increasing dissimilarities between sites with cluster analysis. Although the result of the present study was a case study using ground beetles, it will be helpful to develop a management strategy of biodiversity conservation in Naejangsan National Park and its surroundings.

• 산업경영시스템학회지
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• 제40권2호
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• pp.51-59
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• 2017

Due to the rapid change of global business environment, the growth of China's steel industry and the inflow of cheap products, domestic steel industry is faced on downward trend. The change of business paradigms from a quantitative growth to a qualitative product is needed in this steel industry. In this environment, it is very important for domestic steel distribution companies to secure their competitiveness by selecting good supply companies through a efficient procurement strategy and effective method. This study tried to find out the success factors of steel distribution industry based on survey research from experts. Weighted values of each factors were found by using AHP (analytic hierarchy process) analysis. The weighted values were applied to DEA(data envelopment analysis) model and eventually the best steel supply company were selected. This paper used 29 domestic steel distribution firms for case example and 5 steps of decision process to select good vendors were suggested. This study used quality, price, delivery and finance as a selection criteria. Using this four criterions, nine variable were suggested. Which were product diversity, base price, discount, payment position, average delivery date, urgency order responsibility and financial condition. These variables were used as a output variable of DEA. Sales and facilities were used as an input variable. Pairwise comparison was conducted using these variables. The weighted value calculated by AHP pairwise comparison were used for DEA analysis. Through the analysis of DEA efficiency process, good DMU (decision making unit) were recommended as a steel supply company. The domestic case example was used to show the effectiveness of this study.

• 한국수자원학회논문집
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• 제43권4호
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• pp.337-351
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• 2010

극치사상을 예측하기 위한 기존의 빈도분석 결과의 이용에 대한 많은 문제점들이 부각되고 있다. 특히, 통계적 모형을 이용하기 위해서 흔히 사용되는 점근적 모형 (asymptotic model)의 합리적인 검토 없는 외삽 (extrapolation)은 산정된 확률 값을 과대 또는 과소평가하는 문제를 일으켜, 예측결과에 대한 불확실성을 과다하게 산정함으로써 불확실성에 대한 신뢰도를 감소시키는 문제가 있다. 그러므로 본 연구에서는 국내에서 극치강우사상을 포함한 강우자료의 빈도분석에 대한 연구사례를 제공하고 점근적 모형을 사용하는 경우 발생되는 불확실성을 감소시키기 위한 방법론을 제시하였다. 이를 위하여 본 연구에서는 극치강우사상의 빈도분석을 수행하는 데 있어서 최근 들어 여러 분야에서 다양하게 적용되고 있는 Bayesian MCMC (Markov Chain Monte Carlo) 방법을 사용하였으며, 그 결과를 최우추정방법 (Maximum likelihood estimation method)과 비교하였다. 특히 강우사상의 점 빈도분석에 흔히 이용되는 확률밀도함수로 GEV (Generalized Extreme Value) 분포와 Gumbel 분포를 모두 고려하여 두 분포의 결과를 비교하였으며, 이 과정에서 각각의 산정결과 및 불확실성은 근사식을 이용한 최우추정방법과 Bayesian 방법을 이용하여 각각 비교 및 분석되었다.

• 전기학회논문지
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• 제65권2호
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• pp.269-278
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• 2016

In order to maintain customer voltages within allowable limit($220{\pm}13V$) as much as possible, tap operation strategy of SVR(Step Voltage Regulator) installed in distribution system is very important, considering the scheduled delay time(30 sec) of SVR. However, the compensation of BESS(Battery Energy Storage System) during the delay time of SVR is being required because the customer voltages in distribution system interconnected with PV(Photovoltaic) system have a difficultly to be kept within allowable limit. Therefore, this paper presents the optimal voltage stabilization method in distribution system by using coordination operation algorithm between BESS and SVR. It is confirmed that customer voltage in distribution system can be maintained within allowable limit($220{\pm}13V$).

• 통상정보연구
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• 제13권3호
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• pp.511-541
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• 2011

본 연구에서는 앞으로 있을 한 중 FTA협상 추진 전략을 중국의 낮은 수준의 FTA 체결 선(先)제의에 대한 우리나라의 최적 대응전략 측면에서 고찰하였다. 국제협상 분석 게임모델 중 비협조게임의 기본 모형인 죄수의 딜레마 게임을 기본 틀로 하여 Putnam의 2단계 게임 론을 활용하여 결론을 도출하였다. 향후 한 중 FTA 추진의 전략적 기본원칙은 정부가 주장하는 높은 관세양허 수준의 포괄적 FTA보다는 비록 경제적 효과가 다소 떨어지더라도 가능한 빠른 시일 내 '중간 수준'의 FTA(포괄적이나 전반적으로 낮은 관세양허 방안)를 시작하는 정책을 추진함이 바람직 할 것으로 결론지었다. 이러한 관점에서 한 중 양국이 상대국으로부터의 수입액 중 일정 비율, 가령 70-80%에 해당하는 품목에 대해 협상개시와 함께 관세를 내리는 조기수확 프로그램(EHP: Early Harvest Program)을 활용하는 전략도 한 방법이 될 것이다.