• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.193-200
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• 2010

Structural design requires simultaneously to ensure safety by considering quantitatively uncertainties in the applied loadings, material properties and fabrication error and to maximize economical efficiency. As a solution, system reliability-based design optimization (SRBDO), which takes into consideration both uncertainties and economical efficiency, has been extensively researched and numerous attempts have been done to apply it to structural design. Contrary to conventional deterministic optimization, SRBDO involves the evaluation of component and system probabilistic constraints. However, because of the complicated algorithm for calculating component reliability indices and system reliability, excessive computational time is required when the large-scale finite element analysis is involved in evaluating the probabilistic constraints. Accordingly, an algorithm for SRBDO exhibiting improved stability and efficiency needs to be developed for the large-scale problems. In this study, a more stable and efficient SRBDO based on the performance measure approach (PMA) is developed. PMA shows good performance when it is applied to reliability-based design optimization (RBDO) which has only component probabilistic constraints. However, PMA could not be applied to SRBDO because PMA only calculates the probabilistic performance measure for limit state functions and does not evaluate the reliability indices. In order to overcome these difficulties, the decoupled algorithm is proposed where RBDO based on PMA is sequentially performed with updated target component reliability indices until the calculated system reliability index approaches the target system reliability index. Through a mathematical problem and ten-bar truss problem, the proposed method shows better convergence and efficiency than other approaches.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.5
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• pp.413-419
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• 2008

Deterministic design optimization (DO) does not explicitly deal with a variety of factors from inherent randomness and uncertainties. Reliability based design optimization(RBDO) is necessary to use in engineering systems in order to guarantee quality and performance of product. In this paper, design variables are considered as random variables. Standard deviation according to change of design variables have changed as much as coefficient of variation. And, if the standard deviation is error of manufacturing, standard deviation-mean relation is concave form. We obtain reliability index using advanced first order second moment method(AFOSM). This paper is examined by solving two examples and the results are compares with DO, RBDO and suggested RBDO.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.135-135
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• 2017

최근 강우-유출 모형은 물리적 현상에 근거한 확정론적 모의 모형과 물리적 성분으로 설명할 수 없는 내용에 대해 통계적으로 접근하는 추계학적 모의 모형 등이 계속 연구되고 있어 자연현상에 가까운 결과를 기대할 수 있게 되었다. 하지만 우리나라의 경우 많은 연구에도 불구하고 돌발성 집중호우, 여름철 집중되는 강우 등으로 인해 재난이 반복적으로 발생하고 있어 모형의 정확성에 대한 논의가 지속되고 있다. 동일한 유역에 동일한 입력자료를 사용하더라도 사용하는 모형에 따라 유출 분석결과는 상이하며 이는 유출 해석에 대한 불확실성으로 작용한다. 본 연구에서는 앙상블 및 블랜딩 기법을 사용하여 각 강우-유출 모형의 불확실성을 고려하여 최적 유출량을 산정하고자 한다. 대상 유역으로는 한강 수계에 있는 중랑천 유역을 선정하였으며, Distributed 모형인 Vflo 모형과 Lumped 모형인 저류함수 모형, SSARR모형, TANK 모형을 이용하여 유출 분석을 실시하였다. 그 후, Multi-Model Super Ensemble(MMSE), Simple Model Average(SMA), Mean Square Error(MSE) 방법 등의 blending 기법을 이용하여 하나의 통합된 형태의 유출 분석 결과를 제시하였으며, 최적 유출량 산정을 위한 blending 기법을 선정하였다. 본 연구를 통해 동일한 강우 시나리오에 대한 여러 강우-유출 모형에 대한 정확도를 확인하였으며, 앙상블 및 블랜딩 기법을 사용하여 유출 분석에 대한 정확도를 향상시킬 수 있을 것으로 판단된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2321-2324
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• 2002

현재의 웹은 시각적인 표현을 위한 것으로써 정보를 사람에게 어떻게 보여줄 것인가에 대해서 초점을 두고 개발되었다. 따라서 폭발적으로 증가하는 웹 데이터에서 사용자가 원하는 정보를 신속 정확하게 찾는 것은 점점 어렵게 되었다. 이를 개선하기 위해 자연언어처리, 에이전트, 검색엔진 등과 같은 기술을 개발하였으나 정보와 표현을 위한 태그의 혼합으로 컴퓨터가 정보를 효과적인 추출 및 이해하는데 한계가 있다. 이는 지금까지의 웹 기술로써는 다양한 표현과 사용하기 쉽지만 정보의 의미표현이 부족하기 때문이다. 이러한 문제점을 해결하기 위해 정보를 온톨로지로써 개념화하고 이를 컴퓨터가 이해하며 이기종 컴퓨터간의 자유로운 정보접근을 위해 1990년 대 말에 시맨틱 웹이 제안되었다. 현재 시맨틱 웹은 RDF(S), OIL. DAML, SHOE 등과 같은 마크업 언어가 연구 개발 중에 있으나 이 역시 지식표현 분야 위주의 연구로 그 한계가 있다. 이에 본 논문에서는 시맨틱 웹을 위한 지금까지의 마크업 언어에 대한 분석을 하고, 효과적인 시맨틱 웹의 구현을 위한 객체지향의 마크업 언어를 제안한다. 본 논문에서 제안하는 마크업 언어는 이기종의 분산환경에 적합하고 재사용성 및 확정성에 용이하는 등의 장점들을 갖고 있다.

• Journal of the Korean earth science society
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• v.26 no.5
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• pp.376-386
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• 2005

This study investigated to describe how the nature of science is revealed in the four natural history museums in Korea. Natural history museums are well considered as informal settings of education, and the nature of science has been one of major topics stressed in science education. Therefore, the revelation of this topic is supposedly reflected in developing museum exhibitions. In each of the four target natural history museum or natural history exhibition, the representative exhibits subtitled by scientific inquiry and cases dealing with history of science were selected for the study. The analyzing exhibits focused on whether exhibitions were labeled with emphasis on declarative description or interpretative one. In analyzing the contents, the focus was on the concerns of scientists, scientific community, social and cultural aspects, uncertainty of scientific knowledge, and providing sufficient evidences. All things considered, it was hard to conclude that every target exhibit clearly considered the nature of science as an essential element, in designing and developing their exhibitions. More deliberate input of nature of science is suggested for worldly renowned natural history museums, because previous researches keep insisting that the nature of science would be more efficiently achieved in an informal educational setting rather than in classrooms.

• Journal of Korean Society of Transportation
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• v.21 no.2
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• pp.95-105
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• 2003

Because the basic assumptions of deterministic user equilibrium assignment that all network users have perfect information of network condition and determine their routes without errors are known to be unrealistic, several stochastic assignment models have been proposed to relax this assumption. However. it is not easy to solve such stochastic assignment models due to the probability distribution they assume. Also. in order to avoid all path enumeration they restrict the number of feasible path set, thereby they can not preciously explain the travel behavior when the travel cost is varied in a network loading step. Another problem of the stochastic assignment models is stemmed from that they use heuristic approach in attaining optimal moving size, due to the difficulty for evaluation of their objective function. This paper presents a logit-based stochastic assignment model and its solution algorithm to cope with the problems above. We also provide a stochastic user equilibrium condition of the model. The model is based on path where all feasible paths are enumerated in advance. This kind of method needs a more computing demand for running the model compared to the link-based one. However, there are same advantages. It could describe the travel behavior more exactly, and too much computing time does not require than we expect, because we calculate the path set only one time in initial step Two numerical examples are also given in order to assess the model and to compare it with other methods.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.70-79
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• 2016

The current remodeling cost estimation process is not only dependent on the historical data of new building construction, but it also has a poor linkage with risk-based estimation approach. As such, there is a high risk of falling short of initial budget. To overcome this, a risk-based estimation approach is necessary by providing a probabilistic estimation in consideration of the potential risk factors in conducting the remodeling projects. In addition, the decision-making process should be linked with the risk-based estimation results in stead of intuitive and/or experience-based estimation. This study provides a probabilistic estimation process for residential remodeling projects by developing a detailed methodology in which a step-by-step approach can be achieved. The new proposed estimation approach can help in decision-making for remodeling projects in terms of whether to proceed or not, by effectively reflecting the potential risk factors in the early stage of the project. In addition, the study can enhance the reliability of the estimation results by developing a sustainable estimation process model where a risk-based evaluation can be accomplished by setting up the cost-risk relationship database structure.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.7
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• pp.17-26
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• 2016

Information spill was occurred several times in the country due to the negligence of the large internet service providers including SK Communications, Auction, KT. In order to judge the Internet Service Provider(ISP)'s liability in individual data spill caused by hacking, the violation of existing legislation or general principle of law's good faith principle has to be examined. However, based on current ISP's good faith principle, there is no objective standard for judging liability. Such uncertain range of protection action duty based on good faith principle generates complaint toward companies, therefore presentation of objective judgement range index on how to determine this range is needed. However due to the legal characteristic of above-mentioned law, it is not possible to fix the range of protection action duty and regulate it on law. In order to resolve this, rather than concerning simply on legal system level, fusion approach method is needed. Thus, this research will discuss the measure for objective standard for predicting ISP's range of protection action duty through fusion view dividing in technical, legal and administrative aspects.

• Journal of Korea Water Resources Association
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• v.35 no.3
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• pp.331-344
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• 2002

This study is aimed at the development of a deterministic runoff model which can be used for flood runoff. The model is formulated by the watershed runoff model. Based on the assumptions that runoff system is nonlinear, the proposed watershed runoff model is the conceptual model. In the model structure, the conceptual model divides the runoff system into a surface structure and a subsurface structure corresponding to the surface flow, and inter flow and ground water flow respectively. The lag time effect of surface can be represented by the sub-tank of surface structure in the conceptual model. The parameter calibration of inter flow and ground water flow in the subsurface structure of the conceptual model is performed by separating the components with numeric filter The runoff coefficient($\alpha$$_2$) is expressed as the function of antecedent precipitation index(API). The parameters with the surface flow can be calibrated with the runoff coefficient($\alpha$$_1$ and $\alpha$/$_{11}$) in the conceptual model. In the conceptual model, an algorithm is developed to calibrate the parameters automatically based on efficiency criteria. The comparative study shows that simulated value from the conceptual model well agreed to observed value.

• Journal of the Korea Convergence Society
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• v.12 no.3
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• pp.297-304
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• 2021

This study aims not only to access the visual thought-oriented approach that has been implemented in established art therapy and education but also to integrate language education and therapeutic approach to support the development of school-age children. Thus, text mining technique was applied to search for areas where different areas of language and art can be integrated. This research was conducted in accordance with the procedure of basic research, preliminary DB construction, text screening, DB pre-processing and confirmation, stop-words removing, text mining analysis and the deduction about the convergent areas. These results demonstrated that this study draws convergence areas related to regional, communication, and learning functions, areas related to problem solving and sensory organs, areas related to art and intelligence, areas related to information and communication, areas related to home and disability, topics, conceptualization, peer-related areas, integration, reorganization, attitudes. In conclusion, this study is meaningful in that it established a framework for designing an activity-centered convergence program of art and language in the future and attempted a holistic approach to support child development.