• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.1
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• pp.10-17
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• 2018

To prepare the integrated safety management system 'e-navigation', research is being conducted on the route exchange for sharing intended routes between ship and ship, and between ship and land. But they don't have enough specific grounds for the effects of route exchange and the necessity of its introduction and focus on technical aspects like the implementation of route exchange. This study tried to quantitatively analyze the effects of route exchange on sailing safety with the use of ship handling simulation, integrate simulation performers' subjective evaluations, and investigate the effects of route exchange. The ship-to-ship route exchange resulted in the initial collision avoidance action time was 3.43 minutes faster, the collision avoidance direction change rate was 60 %, the proximity to target A was 31 %, and Mean Rudder Angle Index decreased by 57 %. In addition, 95 % of the survey respondents had an effect on the decision making of collision avoidance, 85 % had a positive impact on safety navigation, 90 % had an accident prevention effect, 70 % reduced the psychological burden of officers, and 70 % should be introduced in practice.

• Journal of KIISE:Databases
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• v.34 no.6
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• pp.554-563
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• 2007

The e-Marketplace is growing rapidly and providing a more complex relationship between providers and consumers. In recent years, e-Marketplace integration or cooperation issues have become an important issue in e-Business. The e-Catalog is a key factor in e-Business, which means an e-Catalog System needs to contain more large data and requires a more efficient retrieval system. This paper focuses on designing an efficient retrieval system for very large e-Catalogs of large e-Marketplaces. For this reason, a new similarity measure for e-Catalog retrieval based on semantic relationships was proposed. Our achievement is this: first, a new e-Catalog data model based on semantic relationships was designed. Second, the model was extended by considering lexical features (Especially, focus on Korean). Third, the factors affecting similarity with the model was defined. Fourth, from the factors, we finally defined a new similarity measure, realized the system and verified it through experimentation.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.21-34
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• 2016

In the design and develop a virtual character, it is important to correctly deliver target emotions generated by the combination of facial expression and gesture. The purpose of this study is to examine the effect of congruent/incongruent between gesture and facial expression on target emotion. In this study four emotions, joy, sadness, fear, and anger, are applied. The results of study showed that sadness emotion were incorrectly perceived. Moreover, it was perceived as anger instead of sadness. Sadness can be easily confused when facial expression and gestures were simultaneously presented. However, in the other emotional status, the intended emotional expressions were correctly perceived. The overall evaluation of virtual character's emotional expression was significantly low when joy gesture was combined with sad facial expression. The results of this study suggested that emotional gesture is more influential correctly to deliver target emotions to users. This study suggested that social cues like gender or age of virtual character should be further studied.

• Journal of Intelligence and Information Systems
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• v.15 no.3
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• pp.81-102
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• 2009

In this study, we investigated how to achieve differentiation for the ISM (Internet Shopping Mall) to improve profitability, which is required for survival in the fiercely competitive ISM industry. We analyzed implementation level key managerial factors that could contribute to the differentiation of the ISM. The research model is constructed through integration of two distinctive research streams of e-commerce. The one is B2C differentiation strategy research, most of which are conceptual and conducted at a strategy level, and the other is empirical research analyzing the antecedents of customer satisfaction at the ISM. This study is organized as follows. First, we draw upon transaction cost theory to organize constructs representing customer value associated with the customer buying decision process. Next, after reviewing comprehensive managerial factors that could impact on customer value, we selected 15 managerial factors that could contribute to the differentiation of the ISM to deliver value to customers. Finally, the resulting structural model is validated through empirical analyses. The results provide insights for future studies on ISM differentiation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2078-2082
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• 2010

The general bus system architecture consists of masters, slaves, arbiter, decoder and so on in shared bus. As several masters can't use a bus concurrently, arbiter plays an role in bus arbitration. In compliance with the selection of arbitration method, The efficiency of bus usage can be determined. Fixed Priority, Round-Robin, TDMA, Lottery arbitration are studied in conventional arbitration method. Conventional arbitration method is considered bus priority primarily, actual bus utilization didn't considered. In this paper, we propose arbitration method using bus utilization operating block of each master, we verify the performance compared with the other arbitration methods through throughput performance. From the result of performance verification, we confirm that proposed arbitration method, matched bus utilization set by the user 40%, 20%, 20%, 20%.

• Journal of KIISE
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• v.44 no.12
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• pp.1258-1268
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• 2017

Capturing real-time daily information on food prices is invaluable to help policymakers and development organizations address food security problems and improve public welfare. This study analyses the possible use of large-scale online data, available due to growing Internet connectivity in developing countries, to provide updates on food security landscape. We conduct a case study of Indonesia to develop a time-series prediction model that nowcasts daily food prices for four types of food commodities that are essential in the region: beef, chicken, onion and chilli. By using Twitter price quotes, we demonstrate the capability of social data to function as an affordable and efficient proxy for traditional offline price statistics.

• The KIPS Transactions:PartB
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• v.19B no.1
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• pp.31-36
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• 2012

In recent years, there has been increasing interest in recommender systems which provide users with personalized suggestions for products or services. In particular, researches of collaborative filtering analyzing relations between users and items has become more active because of the Netflix Prize competition. This paper presents the reinforcement learning approach for collaborative filtering. By applying reinforcement learning techniques to the movie rating, we discovered the connection between a time sequence of past ratings and current ratings. For this, we first formulated the collaborative filtering problem as a Markov Decision Process. And then we trained the learning model which reflects the connection between the time sequence of past ratings and current ratings using Q-learning. The experimental results indicate that there is a significant effect on current ratings by the time sequence of past ratings.

• Journal of the Korean Vacuum Society
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• v.15 no.3
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• pp.325-330
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• 2006

In order to verify the integrity of the first wall (FW) of the International Thermonuclear Experimental Reactor (ITER), the fabricated Cu/SS mock-up is tested in the JAEA Electron Beam Irradiation Test Stand (JEBIS). To fabricate the Cu/SS mock-up, CuCrZr and 316L authentic stainless steel (SS316L) are used for Cu alloy and steel, respectively The hot isostatic pressing (HIP) is used as a manufacturing method with a $1050^{\circ}C$ and 150 MPa. The high heat flux (HHF) test is performed using an electron beam with a heat flux of $5MW/m^2$ and a cycle of 15-sec on time and 30-sec off time. The temperature measurement in the HHF test shows good agreement with the results obtained from ANSYS code analysis, which is used for determining the HHF test conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1639-1643
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• 2008

국내에서의 범람홍수 및 범람으로 인한 제방붕괴 특성은 그 해석상의 어려움으로 인해 주로 과거 범람상황 및 지형도를 통한 경험적 추정 등에 의존해 오고 있는 실정으로 정교한 물리학적 이론에 근거하지 못하였으므로 범람홍수량, 제방의 붕괴폭 등을 정확하게 예측하기에는 미흡한 점이 많았다. 도시하천과 같이 제방 인접한 곳에 주거, 산업시설 등이 밀집하고 있는 지역에서의 제방붕괴로 인한 홍수류의 범람은 막대한 인명 및 재산피해를 발생시키는 큰 재해가 될 수 있다. 본 연구를 통해서 홍수시 제방월류로 인한 제방붕괴 양상을 예측하고 이를 통해 범람유량의 정확한 예측을 통하여 도시하천 제방 계획시 홍수피해와 투자액을 감안한 경제적인 하천 제방단면 결정을 위한 기본자료로 활용될 수 있고, 도시 중요시설물의 입지 선정시 홍수피해에 대한 판단자료로 이용될 수 있을 것이다. 본 연구에서 개발된 모형을 이용하여 Teton 댐, Mantaro landslide 댐, Spirit Lake 장애물 댐 등에 적용하여 개발된 모형의 정확성을 입증하였다. 적용결과 개발된 모형은 기존의 모형과 같은 결과를 나타내어 국내 계산환경에 적용가능함을 보여 앞으로 이용가능성이 큰것을 알 수 있었다. 적용결과 파이핑의 발생위치의 영향은 대체로 파이핑의 위치가 제체의 윗부분에 위치할수록 최대 유출량은 커지는 것으로 나타났으나 Lawn Lake 댐의 경우에는 사면의 식생의 영향으로 다른 결과를 나타내었다. 점착력은 경우에는 점착력이 클수록 유출량의 크기는 감소하는 것으로 나타났으며 마찰각은 최대 붕괴폭의 크기 및 발생시간, 댐의 높이와 폭, 저수용량 등과 유출량이 연관있어 좀 더 많은 계산결과를 이용하여 심도있는 고찰이 요구되었다. 입자의 중간크기, 공극률, 균일성의 경우 적용된 댐들 모두 유사한 결과를 나타내었고 변수들이 커질수록 유출량도 증가하였다. 댐 사면 경사의 경우에는 상,하류 사면 모두 경사가 완만할수록 유출량이 감소하였다. 위의 결과를 통해 개발된 제방붕괴 해석모형은 좀 더 많은 연구와 적용을 통해 개선과 검증이 이루어진다면 국내 제방붕괴해석에 필요한 해석모형이 될 수 있다고 판단되었다.

• Journal of Korea Water Resources Association
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• v.43 no.7
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• pp.597-608
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• 2010

In this study, a method for soil moisture estimation was proposed to obtain the nationwide soil moisture distribution map using on-site soil moisture observations, rainfall, surface temperature, NDVI, land cover, effective soil depth, and CART (Classification And Regression Tree) algorithm. The method was applied to the Yong-dam dam basin since the soil moisture data (4 sites) of the basin were reliable. Soil moisture observations of 3 sites (Bu-gui, San-jeon, Cheon-cheon2) were used for training the algorithm and 1 site (Gye-buk2) was used for the algorithm validation. The correlation coefficient between the observed and estimated data of soil moisture in the validation sites is about 0.737. Results show that even though there are limitations of the lack of reliable soil moisture observation for various land use, soil type, and topographic conditions, the soil moisture estimation method using ancillary data and CART algorithm can be a reasonable approach since the algorithm provided a fairly good estimation of soil moisture distribution for the study area.