• Steel and Composite Structures
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• 제13권2호
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• pp.109-122
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• 2012

An efficient and accurate algorithm is proposed to evaluate the reliability of cable-stayed bridges accounting for soil-pile interaction. The proposed algorithm integrates the finite-element method and the response surface method. The finite-element method is used to model the cable-stayed bridge including soil-pile interaction. The reliability index is evaluated based on the response surface method. Uncertainties in the superstructure, the substructure and load parameters are incorporated in the proposed algorithm. A long span steel cable-stayed bridge with a main span length of 1088 m built in China is considered as an illustrative example. The reliability of the bridge is evaluated for the strength and serviceability performance functions. Results of the study show that when strength limit states for both girder and tower are considered, soil-pile interaction has significant effects on the reliability of steel cable-stayed bridges. Further, a detailed sensitivity study shows that the modulus of subgrade reaction is the most important soil-pile interaction-related parameter influencing the reliability of steel cable-stayed bridges.

• Smart Structures and Systems
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• 제14권2호
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• pp.129-144
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• 2014

In this paper, a fuzzy inference system and an analytical hierarchy process-based online evaluation technique is developed to monitor the condition of the 32-km Donghai Bridge in Shanghai. The system has 478 sensors distributed along eight segments selected from the whole bridge. An online evaluation subsystem is realized, which uses raw data and extracted features or indices to give a set of hierarchically organized condition evaluations. The thresholds of each index were set to an initial value obtained from a structure damage and performance evolution analysis of the bridge. After one year of baseline monitoring, the initial threshold system was updated from the collected data. The results show that the techniques described are valid and reliable. The online method fulfills long-term infrastructure health monitoring requirements for the Donghai Bridge.

• 기술사
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• 제33권3호
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• pp.12-14
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• 2000

Korean government adopted nuclear energy as a key energy source to reconstruct the shattered Korean economy caused by the oil shock in the 1970s, by securing cheap and stable electricity supply. During the 1980s, nuclear energy Played a crucial role as a foundation stone in the rapid growth of Korean economy. In addition, since 1997 nuclear energy has discharged its duty as a leading energy source to overcome the IMF foreign currency crisis. Finally, in 1999 the Korean nuclear power plants achieved the highest performance results compared with others in the world. In this article, I am going to look through the current status of Korean nuclear power generantion with an index of its development and I would like to suggest necessary tasks to Korean nuclear power industries to become more competitive in the future.

• 벤처창업연구
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• 제6권2호
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• pp.97-113
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• 2011

빠르게 변화하는 글로벌 경쟁 환경에서 대학의 역할은 무엇인가 하는 질문이 계속되고 있다. 현재 국내의 대학들은 산업에서의 요구보다는 언론 및 여러 평가기관에서 실시하는 대학 평가 기준에 더 많은 관심을 기울인다. 대학 평가 지표가 비록 널리 인정받는 기준임에는 틀림없지만 효용성에 대한 논란도 항상 공존해 왔다. 따라서 평가 기준에 초점을 맞춘 대학의 발전이 실질적인 대학 본연의 역할에 부합하는지 검토되어야 한다. 본 연구에서는 대학과 기업의 공동 연구를 통해 대학 연구의 산업 파급 효과를 측정하고자 시도한 해외 연구를 국내에 적용시켜 보고, 국내의 대학 평가 기준이 현재의 지표로 충분한 지에 대해 검토하였다. 이 같은 연구는 대학이 단지 연구의 주체가 아니라 창업을 비롯한 다양한 지식확산의 주체가 될 수 있는지 시사점을 제공한다 하겠다. 본 연구는 해외에 발표된 연구 결과만을 분석의 대상으로 삼았다는 한계를 가지고 있으며, 향후 연구에서는 국내에 발표된 연구 결과를 함께 분석해야 할 것이다.

• 상하수도학회지
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• 제35권3호
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• pp.237-246
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• 2021

The ILI, developed by the IWA (International Water Association), has been used in many countries as an indicator of water leakage. In Korea, the revenue water has been used as a performance indicator for waterworks although there is an opinion to replace it with the ILI. Hence, it has been necessary to investigate whether the ILI can replace the revenue water in Korea. The four main operating indicators (i.e., water service population, profit-loss ratio, fiscal self-reliance, and aged pipe rate) of 162 Korean waterworks were compared with the ILI with the linear regression method. Local water authorities with more than 1 million water service population, with more than 60% profit-loss ratio, more than 40% and less than 60% fiscal self-reliance, and more than 20% aged pipe rate showed meaningful correlation between the four parameters and the ILI. In the remaining cases, their correlations were little or weak. This means that using the ILI may not be an efficient method to represent the performance of the water supply system in Korea because of the lack of UARL (Unavoidable Annual Real Losses) data accuracy. To use the ILI in Korea, it will be required to carry out an additional research to accumulate reliable CARL (Current Annual Real Losses) and UARL data in the future.

• Journal of Korea Trade
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• 제23권7호
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• pp.96-112
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• 2019

Purpose - "Trade Facilitation" aims the easier flow of trade across borders, driven not only by effective customs administration, the efficiency of appropriate authorities, but also by telecommunications, the quality of infrastructures and competent logistics. Facilitating trade will help lower trade development costs as well as improve economic development and enhance economic benefits for emerging economies at a time when imports and exports are sent in and out across borders several times in the form of intermediate and final products. Not only that, globalization is being accelerated, which in turn increases competitiveness and this makes logistics one of the key factors when it comes to international trade. Highly efficient logistics services promote product movement, ensure product safety and delivery speed, and reduce trade costs between countries. The purpose of this study is, by using the LPI indices based on gravity model estimates, to analyze the impact of each LPI component on trade with the 20 biggest exporting countries of Northeast Asian countries-Korea, Japan, and China-which account for 19.05% of global exports. Design/methodology - Also, this study statistically analyzes the impact of trade on Northeast Asian countries' top 20 exporting countries, using the LPI indices relevant to Trade Facilitation based on the gravity model estimates. Findings - As a result, it was turned out that the distance, GDP, and the LPI components have relevant impact on the trade exports of all three countries but demonstrated little relation to the demographic perspective. Originality/value - The study also found we can increase the trade volume by improving three countries' trade partners' LPI indices since Korea, Japan, and China share most of their 20 biggest trade partners.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8649-8653
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• 2015

대용량 비디오 데이터베이스들을 효율적으로 관리하기 위해 많은 비디오 색인 및 검색 알고리즘들이 제안되고 있다. 비디오 콘텐츠 관리 시스템에서 비디오 유사도 측정방법은 가장 중요한 기술적 요소 중 하나이다. 본 논문에서는 비디오 유사도를 효율적으로 측정하기 위해 휘도특성 모델을 제안한다. 비디오 색인에 관한 대부분의 알고리즘들이 공통적으로 히스토그램, 윤곽선, 움직임 특성을 사용한 반면 본 논문에서 제안한 알고리즘은 휘도투시를 사용한 효율적인 유사도 측정법을 적용하였다. 비디오 시퀀스의 효율적인 색인과 계산량 감소를 위해 누적된 유사도에 의해 추출된 키프레임 들을 이용한 비디오 유사도를 계산하고 수정된 하우스도르프 거리를 사용하여 키프레임 묶음들을 비교하였다. 실험결과 제안한 휘도투시 모델이 적은 계산량으로 기존의 히스토그램 비교법을 사용한 알고리즘에 비해 현저히 향상된 정확도 및 성능을 보였다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.620-624
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• 2004

건설 사업은 점차 대형화 되어 가면서 건설사업의 관리의 필요성이 대두되고 있다. 국내에서는 1996년에 '건설산업기본법' 제정 시 건설사업관리가 도입되었지만, 제도의 미비 등으로 그다지 활성화되지 못하고 있다 이처럼, CM이 활성화되지 못하는 이유는 기존에 정착한 감리제도와의 마찰 때문이기도 하지만 CM의 성공적인 수행을 위한 체크리스트 의 보급과 성과측정을 통해 CM의 효과를 보급하는 과정이 미흡했기 때문이기도 하다. 국내에서도 CM이 도입된 지 10여년이 지나면서 조금씩 발전해 가고 있지만, 선진국에 비해 성과측정과 평가를 통한 활성화는 부진한 실정이다. 본 논문에서는 프로젝트 차원에서 CM분야와 요소 기술을 고려한 Best Practice 체크리스트를 개발하여 성과측정 시 보다 나은 결과를 도출하기 위한 기초를 마련하고자 한다.

• International Journal of Automotive Technology
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• 제4권2호
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• pp.95-100
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• 2003

Automobile industry has been developed rapidly as a key manufacturing industry in Korea. Meanwhile, air pollution is getting worse noticeably than ever. In the diesel emission, PM (Particulate Matter) and NOx (Nitrogen Oxides) have been exhausted with a great amount and the corresponding emission regulations are getting stringent. In order to develop low emission engines, it is necessary to research on better qualified fuels. Sulfur contained in fuel is transformed to sulfur compound by DOC (Diesel Oxidation Catalyst) and then it causes to the increase of sulfate-laden PM on the surface of catalyst. In this research, ULSD (Ultra Low Sulfur Diesel) is used as a fuel and some experimental results are investigated. ULSD can reduce not only PM but also gas materials because cetane value, flash point, distillation 90%, pour point and viscosity are improved in the process of desulfurization. However, excessively reduced sulfur may cause to decease lubricity of fuel and engine performance in fuel injection system. Therefore, it requires only modest adjusted amount of sulfur can improve engine performance and DOC, as well as decrease of emission.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권5호
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• pp.1992-2008
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• 2018

Mobile opportunistic network is a kind of ad hoc networks, which implements the multi-hop routing communication with the help of contact opportunity brought about by the mobility of the nodes. It always uses opportunistic data transmission mode based on store-carry-forward to solve intermittent connect problem of link. Although many routing schemes have been proposed, most of them adopt the greedy transmission mode to pursue a higher delivery efficient, which result in unfairness extremely among nodes. While, this issue has not been paid enough attention up to now. In this paper, we analyzed the main factors that reflect fairness among nodes, modeled routing selection as a multiple attribute decision making problem, and proposed our Fairness-aware Routing Strategy, named FARS. To evaluate the performance of our FARS, extensive simulations and analysis have been done based on a real-life dataset and a synthetic dataset, respectively. The results show that, compared with other existing protocols, our FARS can greatly improve the fairness of the nodes when ensuring the overall delivery performance of the network.