• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.3
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• pp.311-321
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• 2020

In this study, coefficient of variation for the seismic load effect on the segment lining was calculated. The statistical characteristics of the soil property were analyzed for the probability characteristics of domestic soil. In order to calculate the coefficient of variation for the seismic load effect, the MCS technique was applied, and the closed-form equation was applied to calculate the seismic load effect. As a result of calculating the coefficient of variation, the coefficient of variation of the seismic load effect on the weathered soil was analyzed in the range of 0.06~0.15, and the coefficient of variation was judged to be used as basic data for designing the limit state of the shield tunnel on seismic condition.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.383-389
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• 2018

Recently, it has been reported that water pollution due to non-point pollutants continues. Studies have been actively carried out to prevent such non-point pollutants from flowing into the water system and to prevent water pollution. In this study, to evaluate the adequate design of the LID facilities the rainfall corresponding to 80% of the cumulative rainfall of Yongin city was applied to an SA / CA graph obtained from the analysis of monitoring results of the vegetation type LID facility. As a result, the appropriate SA/CA ratio was 0.6% for stormwater sustain efficiency 80% and the appropriate SA/CA ratio was 0.5% for TSS removal efficiency 80%. The appropriate SA/CA ratio of the vegetation type LID proposed in this study can be used as a basis. for the future vegetation type LID design. If more data of vegetation type LID are added through continuous research, it will be more accurate.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.123-124
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• 2019

우리나라 조선업은 건조분야에서 세계최고의 위상을 자랑하면서 급속도로 발전을 해왔다. 그러나 세계적으로 수주 불황과 조선 산업의 침체로 인해서 조선 산업은 직접적인 타격으로 국내의 중견 조선소 및 기자재 공급업체들이 도산되어0 최근부터 해양플랜트 사업이 우리나라 새로운 산업으로 부상하면서 해양 ICT 융합기술을 활용한 기자재 업체들이 많이 생겨났다. 하지만 실제 해양플랜트 선박 및 기자재의 국산화율은 현저히 낮다. 해양플랜트 외에 다른 용도로 사용이 가능한 Service and Access Basket의 국산화를 위해서 각 모듈별로 임베디드를 연계하여 설계하였다. 기존의 Service and Access Basket의 미비했던 안전 사양(기울기, 하중, 경보 등)을 추가로 설계하고 신뢰성이 높은 센서(자이로, 하중센서, 초음파 거리센서)들을 활용하여 통합 설계하였다. 이러한 통합 시스템이 완성이 되면 고소차, 해양/육상용 고공 작업을 할 수 있는 장비 등에 활용할 수 있을 예정이다.

• Korean Journal of Construction Engineering and Management
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• v.21 no.1
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• pp.50-60
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• 2020

Estimates of project costs in the early stages of a construction project have a significant impact on the operator's decision-making in important matters, such as the site's decision or the construction period. However, it is difficult to carry out the initial stage with confidence because information such as design books and specifications is not available. In previous studies, case-based reasoning was used to predict initial construction costs, and genetic algorithms were used to calculate the weight of the inquiry phase among them. However, some say that it is difficult to perform better than the current year because existing genetic algorithms are calculated in random numbers. To overcome these limitations, correlation numbers using correlation analysis rather than random numbers are reflected in the genetic algorithm by method of local search, and weights are calculated using a hybrid genetic algorithm that combines local search and genetic algorithms. A case-based reasoning model was developed using the weights calculated and validated with the data. As a result, it was found that the hybrid GA-CBR applied with local search performed better than the existing GA-CBR.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.42-50
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• 2008

The real-time bio-signal monitoring system based on the ZigBee and SIP/RTP has proposed and implemented for telemedicine but that has some problems at the stabilities to transmit bio-signal from the sensors to the other sides. In this paper, we designed and implemented a real-time bio-signal monitoring system that is focused on the reliability and efficiency for transmitting bio-signal at real-time. We designed the system to have enhanced architecture and performance in the ubiquitous sensor network, SIP/RTP real-time transmission and management of the database. The Bluetooth network is combined with ZigBee network to distribute traffic of the ECG and the other bio-signal. The modified and multiplied RTP session is used to ensure real-time transmission of ECG, other bio-signals and speech information on the internet. The modified ECG compression method based on DWLT and MSVQ is used to reduce data rate for storing ECG to the database. Finally we implemented a system that has improved performance for transmitting bio-signal from the sensors to the monitoring console and database. This implemented system makes possible to make various applications to serve U-health care services.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.791-800
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• 2013

Needs for developing a better way of cost estimating process for public construction projects have been widely recognized. Those needs are mainly from the early phases of the project through the construction life cycle due to the its importance to the control process. In contrast to the traditional estimating method based on unit-price references, this research utilized this following process. The first step is analyzing the real cost data from actual cost activities (2000~2010) about the statement of P.S.C(Prestressed Concrete) Box Girder Bridge. The collected data was broken into four categories based on technical construction methods such as I.L.M(Incremental Launching Method), M.S.S(Movable Scaffolding System), F.S.M(Full Staging Method), and F.C.M(Free Cantilever Method). The second, actual design documents including the actual cost estimating documents, drawings and specifications were carefully reviewed to cluster the cost itemized statement from four categories. It was also attempted to seek the proper breakdown of standard works that are responsible for more than 95 percentage in each categories in terms of its cost. The third, this research comes up the index for standard unit materials and unit price of standard work and develops the approximate estimating model applying for the specification(length and breadth of bridges) per square area that the user takes as well as suggests the practical application plan within the original time alloted.

• Journal of the Korean Geotechnical Society
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• v.37 no.5
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• pp.47-63
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• 2021

Recently, the demand for three-dimensional (3D) underground maps from the perspective of digital twins and the demand for linkage utilization are increasing. However, the vastness of national geotechnical survey data and the uncertainty in applying geostatistical techniques pose challenges in modeling underground regional geotechnical characteristics. In this study, an optimal learning model based on multi-layer perceptron (MLP) was constructed for 3D subsurface lithological and geotechnical classification in Seoul, South Korea. First, the geotechnical layer and 3D spatial coordinates of each borehole dataset in the Seoul area were constructed as a geotechnical database according to a standardized format, and data pre-processing such as correction and normalization of missing values for machine learning was performed. An optimal fitting model was designed through hyperparameter optimization of the MLP model and model performance evaluation, such as precision and accuracy tests. Then, a 3D grid network locally assigning geotechnical layer classification was constructed by applying an MLP-based bet-fitting model for each unit lattice. The constructed 3D geotechnical layer map was evaluated by comparing the results of a geostatistical interpolation technique and the topsoil properties of the geological map.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.6-6
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• 2023

국토교통부는 R&D 사업인 '분산공유형 건설연구인프라구축사업(2004년~2009년, 6종)'과 '국토교통기술실험인프라 2단계 구축사업(2013년~2019년, 6종)'을 통해 첨단 연구시설·장비를 전국에 분산 구축하여 실험시설이 부족한 중소기업·대학 등이 공동활용할 수 있도록 총 12종의 건설분야 대형실험시설을 구축하였다. 국토교통 R&D 성과(기술·제품)의 품질 및 신뢰성 확보를 통해 개발기술의 상용화 촉진을 위해서는 이러한 국토교통 대형실험시설·장비를 활용한 표준화된 성능평가 시험기반(표준실험절차, 단체표준 등)을 구축하여 연구인프라의 공동활용을 촉진하고 기술개발 성공률 제고와 함께 건설분야 시험인증 산업을 육성할 필요가 있다. 국토교통 대형실험시설을 활용하여 건설분야 기술·제품에 대한 성능평가 기반의 실험절차를 표준화함으로써 성능평가 결과의 신뢰성 확보 및 기술시험서비스 역량 제고를 위한 '건설분야 기술·제품의 검증을 위한 성능기반 표준실험절차 개발(연구기간: '17.06~'22.06, 연구비: 총99억원, 주관기관: 국토교통연구인프라운영원)' 과제가 성공적으로 수행 완료되었다. 이 과제를 통해 총 53개의 표준실험절차서와 20개의 단체표준이 제정되었다. 이어서, 2단계 대형실험시설 준공완료에 따라 '건설분야 성능기반 표준시험절차 개발 사업(연구기간: '21.04~'25.12, 연구비: 총143.8억원)이 수행되고 있다. 현재, 국토교통연구인프라운영원은 이 사업 내 국제융합수리(주관기관: 한국농어촌공사 농어촌연구원), 극한성능(주관기관: 서울대학교) 및 기상환경재현(주관기관: 한국건설기술연구원) 표준실험절차 개발 과제에 공동기관으로 참여하여 단체표준 개발업무를 담당하고 있다. 본 논문에서는 단체표준 소개 및 현황에 대해 설명하고, 1단계 표준실험절차 개발과제를 통해 정립되었고 현재 2단계 표준실험절차 개발과제에도 적용되고 있는 시험관련 단체표준(안) 개발 프로세스에 대해 기술하고자 한다. 개발된 단체표준은 건설관련 실험·시험시설을 보유한 기관(대학, 공공기관, 산업체 연구소 등)의 성능검증 시험, 신기술 및 신제품 인증 표준절차에 활용가능하며, 시방서와 설계기준에 KS표준과 같이 시험 및 검사방법에 있어 참조표준으로도 활용 가능하다.

• Journal of Global Scholars of Marketing Science
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• v.17 no.4
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• pp.113-139
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• 2007

This study aims to, looking from a standpoint of network, has investigated the shipping industry's B2B e-marketplace, the characteristics that can earn electronic trust from the users, and characteristics of the web-site. It has examined the mechanism whereby electronic trust be earned and how it affects web-site involvement and service transaction intention. Ultimately, The study attempts to make proposals whereby such trust can lead for a cooperative trading community in the shipping industry's B2B e-marketplace The Covalence structural equation modeling was designed and empirically tested for the shipping industry's B2B e-marketplace. The shipping industry employees were given questionnaires and data were analyzed. Except for perceived security of the three characteristic factors on the web-site, the perceived site quality and characteristics factors in operation only affected co-variables. Transaction Fairness was determined to be the most important factor among exogenous factors increasing electronic trust. With regards to transaction rules, if a transaction is beneficial only to one side, then no long term transaction will not take place. If the concerned parties properly recognize that transaction fairness is crucial to electronic transaction, then it will enormously contribute to successful operations of shipping e-marketplace. Also, Perceived efficiency in transaction also affects electronic trust. This reduces transaction costs and speeds up and simplifies the transaction process. It has reduced greater time and costs than existing off-line transaction, and would positively affect electronic trust. By making an open forum for participants to obtain information for transaction, they can gather useful information, and at the same time, the web-site operator can provide information, which, in turn, will increase electronic trust in electronic transaction. Furthermore, such formation of trust in electronic transaction influences shipping companies in such a way that they will want to continuously participate in the transaction, raising web-site involvement. The result of increased trust is that shipping companies in the future will do business with each other and form a foundation for continuous transactions amongst themselves. Consequently, the formation of trust in electronic transaction greatly influences web-site involvement and service transaction intention. The results of the study have again proved that in order to maintain continuous business relationship with the current clients, electronic trust in virtual space, which operates the shipping industry's B2B e-marketplace, is important for the interested parties.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.10
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• pp.859-876
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• 2012

Since the existing protocols separated mobility management part and routing protocol part in their design and used a flooding, they suffer from the high control overhead, thereby limiting performance. In this paper, we use a tree-based mobility management method and present a simple and efficient routing protocol that exploits the topology information which is built additionally through mobility management. Thus, the mobility management and the routing protocol closely cooperate to optimize control overhead. Furthermore, we use a progressive path discovery method to alleviate traffic congestion around IG and a unicast-based broadcast method to increase the reliability of message delivery and to judge link validity promptly. The proposed protocol reduces control overhead greatly and works in a stable manner even with the large number of nodes and high mobility. This was proven by comparing with the AODV protocol that employs the hybrid mobility management protocol.