• Journal of the Society of Naval Architects of Korea
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• v.36 no.4
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• pp.137-146
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• 1999

Inspection becomes to be important in the safety of structure and economical viewpoint, because structural damage accompanies lots of economical cost and social problems. Especially ship structure is composed of a lot of members and it is impossible to inspect all members continuously. The purpose of this paper is to get optimal inspection plan containing inspection time and method. Crack is one of major modes on the structural failure and can lead to collapse of structure. In this paper, the deteriorating process, which contains inspection to detect the crack before the propagation to large crack, is idealized as Markov chain model. Genetic algorithm is also used to accomplish the optimization of inspection plan. Especially, the probabilistic characteristics of cracks are changed, because ship is operating in corrosive environments and the scantling of structural members is reduced due to corrosion. Non-stationary Markov chain model is used to represent the process of corrosion in structural members. In this paper, the characteristics of indivisual inspection plan are compared by numerical examples for the change of corrosion rate, the cost due to scheduled system down and target failure probability. From the numerical example, it can be seen that the improvement of fatigue life for the members with short fatigue life is the most effective way in order to reduce total maintenance cost.

• Journal of Korea Port Economic Association
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• v.26 no.1
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• pp.222-233
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• 2010

This paper aims at predicting the BDI from Jan. to Dec. 2010 using such econometric techniues of the univariate time series as stochastic ARIMA-type models and Hodrick-Prescott filtering technique. The multivariate cause-effect econometric model is not employed for not assuring a higher degree of forecasting accuracy than the univariate variable model. Such a cause-effect econometric model also fails in adjusting itself for the post-sample. This article introduces the two ARIMA models and five Intervention-ARIMA models. The monthly data cover the period January 2000 through December 2009. The out-of-sample forecasting performance is compared between the ARIMA-type models and the random walk model. Forecasting performance is measured by three summary statistics: root mean squared error (RMSE), mean absolute error (MAE) and mean error (ME). The RMSE and MAE indicate that the ARIMA-type models outperform the random walk model And the mean errors for all models are small in magnitude relative to the MAE's, indicating that all models don't have a tendency of overpredicting or underpredicting systematically in forecasting. The pessimistic ex-ante forecasts are expected to be 2,820 at the end of 2010 compared with the optimistic forecasts of 4,230.

• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.85-107
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• 2022

This study is to analyze the induced effect, network connectivity, and network visualization of the water transportation industry on the overall economy in relation to all industries. For this, various inducement coefficients of the water transportation industry are analyzed using industry linkage analysis and unit structure matrix, and network visualization analysis is performed using network connectivity and NetDraw using Ucinet 6 that utilizes unit structure matrix and inverse matrix function. As a result of the study, analysis results of input coefficient, production inducement coefficient, value-added inducement coefficient, and inter-industry chain effect were presented as various inducement coefficients in the water transportation industry. content was presented. Through this study, the current position and status of the water transportation industry and its relationship with all industries were confirmed, and the strategic relationship with which industries it should be presented was presented. In the future, it is necessary to further analyze the current status and trends of various induced effects, connectivity (centrality), and network visualization analysis using industry-related analysis published since the 2000s.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.1
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• pp.70-77
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• 2021

This paper was reclassified industries related to the 4th industrial revolution into manufacturing, information and communication services, finance and insurance services, and science and technology services by comparing the industry association table with the Korean standard industry classification. And the economic ripple effect was analyzed by exogenizing the four sectors of the industry using a demand-driven model. The wholesale and retail and product brokerage services were measured to be large in the manufacturing, information communication services, and science technology service sector according as a result of analysis of the production inducement effect, added value inducement effect, and employment inducement effect. And the financial and insurance services were analyzed to be large in the financial and insurance services sector. The import inducement effect was analyzed to be the largest in all sectors of the fourth industry. As a result of the forward and backward linkage effect, it was confirmed that the manufacturing and the information communication services sector were the intermediate primary production type sensitive to economic fluctuations. Also it was confirmed that the financial and insurance services and the science technology services sector were the final primary production type.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.185-194
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• 2022

The software industry makes it possible to converge science and Information and Communication Technologies (ICT), create new markets, and create jobs. It is a key industry in the 21^st century knowledge and information age, which is growing very rapidly. This study uses Input-output analysis to derive Linkage effect of the software industry in Korea and the United States (US), and compares the result with CO₂ inducement effect to verify whether the industry meets the low carbon emission development strategy. As the result of this study, first, the software industries in Korea and the US are confirmed to have large influences on the national economy. Second, the Korean software industry has a low Forward linkage effect, so it is less affected by the output of other industries. On the other hand, in the US, it has a high Forward linkage effect and can induce a lot of output in others. Third, CO₂ inducement effects of the industry in Korea and the US are both low, confirming that the industry is suitable for a sustainable future.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.3
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• pp.191-198
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• 2017

To study the behavior of structures subject to blast loads it is important to calculate the loads due to the explosives accurately, especially in the case of interior explosions. It is known that numerical method based on computational fluid dynamics can estimate relatively accurate blast load due to the interior explosion including reflection effect. However, the numerical method has disadvantages that it is difficult to model the analysis and it takes much time to analyze it. Therefore, in this study, the analytical method which can include the reflection effect of the interior explosion was studied. The target structures were set as the slabs of residential buildings subject to interior explosion that could lead to massive casualties and progressive collapses. First, the numerical method is used to investigate the interior explosion effect and the maximum deflection of the slab which was assumed to be elastic, and compared with the analytical method proposed in this study. In the proposed analytical method, we determine the weighting factor of the reflection effect using the beam theory so that the explosion load calculation method becomes more accurate.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.1
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• pp.29-36
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• 2024

This study was carried out to identify the anti-inflammatory effects of Ishige foliacea (I. foliacea) extract on skin using RAW 264.7 cells. The anti-inflammatory effects of I. foliacea extract on RAW 264.7 cells were assessed by cell viability assay, mRNA expressions, and nitric oxide (NO)/prostaglandin E₂ (PGE₂) productions. The anti-inflammatory effects of I. foliacea extract were elucidated by analysis of IL-1α/IL-1β/IL-6/TNFα gene expressions and PGE₂/NO production. Quantitative real-time polymerase chain reaction showed that I. foliacea extract decreased the gene expression levels of iNOS/COX2/IL-1α/IL-1β and IL-6. Furthermore, PGE₂/NO production also revealed that I. foliacea extract exhibited anti-inflammatory properties. These results suggest that I. foliacea extract is an anti-inflammatory compound. It could be a potent cosmeceutical material for anti-inflammatory effects. Further studies on the anti-inflammatory mechanisms of broadleaf extracts are expected to help identify pharmacological mechanisms related to inflammation in addition to cosmeceuticals.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.5-8
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• 2003

요오드화 아연과 수소화 요오드에 의해 개시되는 비닐에테르류 단량체의 양이온 리빙 중합이 보고$^{(1)}$ 된 이래 리빙 중합 개시계에 대한 연구가 많이 진행되어 왔다. 본 연구자들은 광양이온중합 개시제인 요오드화 디페닐요드늄과 할로젠화 아연 존재 하에서 비닐에테르 단량체의 광양이온중합을 실시하여 비극성 용매 하에서 연쇄이동이나 정지반응이 존재하지 않는 리빙중합을 보고한$^{(2-4)}$ 바 있는데 이 중합에서 비닐에테르 단량체와 프로톤산에 의하여 생성된 단량체 adduct의 C-I 결합이 안정한 공유결합을 형성하나 요오드화아연에 의해 C-I 결합의 분극화되어 활성화됨으로서 개시와 성장반응이 가능한 것으로 설명되었다. (중략)

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.537-542
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• 1996

ITU-T에서 표준 비디오 코딩 알고리즘으로 채택한 MPEG 코딩방식은 세 가지의 코딩방식 (I,B,P,방식)을 주기적으로 사용하기 때문에, 코딩된 정보량에 강한 주기성을 보인다. 본 연구에서는 이러한 MPEG 비디오 트래픽의 주기성을 반영하는 개별 비디오 원의 트래픽을 모형화하고 이를 바탕으로 다중화 장치의 성능분석을 실시하였다. 개별 비디오 원에서 발생된 트래픽은 I, B, P의 코딩순서를 반영하고, I, B, P 프레임 별로 셀 수를 모형화 하였다. 그리고 다중화 장치에 입력되는 트래픽은 프레임 시간 단위로 이산화시켜 셀 수를 모형화하였고, 이를 이산시간 마코프 연쇄를 이용해 다중화 장치에서의 셀 손실률을 구하였다. 다중화 장치에서 셀 손실은 입력되는 잘대적인 트래픽의 양 뿐만 아니라, 비디오 원 정렬 (Source Alignment)에도 많은 영향을 받는다. 이러한 비디오 원의 정렬 효과를 반영하여 다중화 장치에 연결될 수 있는 비디오 원의 수를 결정하였다.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.919-922
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• 2010

1997년 이후 한국의 영화산업은 비약적인 성장을 하고 있으며, 고부가가치산업인 문화산업의 한 범주에 속해있다. 문화산업의 발전과 함께 영화산업도 함께 발전하고 있다. 영화산업은 크게 영화상영과 영화제작 및 배급으로 나뉠 수가 있는데, 영화제작은 수많은 재화와 서비스가 연쇄적으로 필요한 부분이며, 이를 포함하고 있는 영화산업은 여러산업과 직?간접적으로 밀접한 연관관계를 맺고 있다. 이에 본 연구에서는 국민경제적 파급효과를 분석하여 보고자 한다. 분석방법으로는 외행화기법을 이용하여 수요유도형 모형, 공급유도형 모형, 레온티에프 가격모형을 이용할 것이다.