• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.11a
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• pp.65-66
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• 2013

제연구역에 설치된 방화문의 개폐 기준은 현실과 괴리가 있고 상당 부분 문제점을 가지고 있다. 우리나라 성인 남녀가 일어서 있는 조건에서 오른손으로 미는 힘을 측정한 결과 국가화재안전기준(NFSC 501A)에서 제시하고 있는 개방력과 차이가 큰 것을 확인할 수 있었다. 20대는 평균 103.31N이었고, 30대는 105.27N, 40대는 100.92N, 50대는 97N, 60대는 91.75N 등으로 측정 되었다. 따라서 NFSC 501A에서 제시하고 있는 기준값의 하향 조정이 필요한 것으로 판단된다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.459-460
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• 2015

현재의 예방정비계획 운영 방법은 KPX에서 발전 사업자들로부터 희망하는 자신들의 발전기 예방정비계획 일정을 받아서 공급예비력 기준을 만족하면 승인을 해주는 방법으로 진행되고 있다. 이는 경제적인 부분을 예방정비계획 수립에 반영하지 못하고 계통의 신뢰도 측면만을 판단하는 것으로 생각할 수 있다. 따라서 발전비용을 최소화하는 예방정비계획 최적화 모델을 적용하여 예방정비계획 수립 시 경제성을 반영하려 한다. 이를 통해 연발전비용을 낮추면서 연평균 SMP 또한 낮춤으로서 한전과 발전사업자 모두에게 이익을 가져다 줄 수 있는 것이다. 따라서 본 연구에서는 비용 최소화를 목적함수로 하는 tool을 적용한 예방정비계획 최적 값과 기존의 예방정비계획을 공급예비율, 계통한계가격(System Marginal Price, SMP), 발전비용 세 가지로 나눠 비교하고 신뢰도와 경제성을 고려한 최적 예방정비계획을 수립하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_2
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• pp.613-623
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• 2007

The main purpose of this study is to investigate the coordinate transformation based on two different systems between local geodetic datum(tokyo datum) and international geocentric datum(new Korea geodetic datum). For this purpose, three methods were used to determine seven parameters as follows: Bursa-Wolf model, Molodensky-Badekas model, and Veis model. Also, we adopted multiple regression equation method to convert from Tokyo datum to KTRF. We used 935 control points as a common points and applied gross error analysis for detecting the outlier among those control points. The coordinate transformation was carried out using similarity transformation applied the obtained seven parameters and the precision of transformed coordinate was evaluated about 9,917 third or forth order control points. From these results, it was found that Bursa-Wolf model and Molodensky-Badekas model are more suitable than other for the determination of transformation parameters in Korea. And, transforming accuracy using MRE is lower than other similarity transformation model.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.787-793
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• 2012

A hull form design technique to enhance the wave-making resistance performance for a medium size high speed Ro-Pax ship was studied introducing an optimization method and an automatic hull form modification method. SQP(sequential quadratic programming) was applied as the optimization algorithm and the geometry of hull surface was represented and modified using the NURBS(Non-Uniform Rational B-Spline). The wave-making resistance performance as an objective function in the optimization procedure was evaluated using the Rankine source panel method in which nonlinearity of the free surface boundary conditions and the trim and sinkage of the ship was fully taken into account. Using the Ro-Pax ship as a base hull, the hull-form optimization method was applied to obtain the hull shape that produced the lower wave-making resistance. To verify the validity of the hull-form optimization method, the numerical results was compared with the model test results.

• The Journal of the Acoustical Society of Korea
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• v.18 no.6
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• pp.31-37
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• 1999

This paper describes the far-field estimation using the near-field measurement data. Measurement in far-field region gives us the acoustical characteristics of the source but in general measurement is made in near-field such as acoustic water tank or anechoic chamber, so far-field acoustical characteristics of the source should be predicted from near-field data. In this case, the number of measurement points in the near field which relates to the accuracy of the predicted field and the amount of data processing, should be optimized. Existing papers say that measurement points is proportional to kL and depends on geometry and directivity of the source. But they do not give us any definite criterion for the required number of measurement points. Boundary Collocation Method which is one of the far-field prediction methods, is analyzed based on Helmholtz integral equation and Green function and it has been found that the number of measurement points is optimized as 0.54kL which is about one half of the existing results.

• Journal of Korean Society of Steel Construction
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• v.12 no.5 s.48
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• pp.503-513
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• 2000

This study treats the criteria, considering the fuzziness occurred by optimization design. And we applied two weighting methods to show the relative importance of criteria. This study develops multi-objective optimization programs implementing plain stress analysis by FEM and discrete optimization design uniformaly. The developed program performs a sample design of 10-member steel truss. This study can carry over the multi-objective optimization based on total system fuzzy-genetic algorithms while performing the stress analysis and optimization design. Especially, when general optimization with unreliable constraints is cannot be solve this study can make optimization design closed to realistic with fuzzy theory.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.4
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• pp.82-92
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• 1997

In this paper, a fuzzy measure and integral-based model fnr interactive systems is proposed. The processes of model identification consists of the following three steps : (i) structure identification (ii) parameter identification and (iii) selection of an optimal model. An algorithm for the model structure identification using the well-known genetic algorithm ((;A) with a modified selection operator is proposed. A method for the identification of par;imetcrs corresponding to fuzzy measures is presented. A statistical model selection criterion is used for the selection of an optimal model among the candidates. Finally, experimental results obtained hy applying the proposed model to the subjective evaluation data set and the well-known time series data are presented to show the validity of the proposed model.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.1
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• pp.1-8
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• 2003

Topology optimization has been evolved into a very efficient conceptual design tool and has been utilized into design engineering processes. Traditional topology optimization has been using homogenization method and optimality criteria method. homogenization method provides relationship equation between structure which includes many holes and stiffness matrix in FEM. Optimality criteria method is used to update design variables while maintaining that volume fraction is uniform. Traditional topology optimization has advantage of good convergence but has disadvantage of too much convergency time. In one way to solve this problem, element removal method using the criterion of an average stress is presented. As the result of examples, it is certified that convergency time is very reduced.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.783-791
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• 2002

An improved formulation for multi-objective optimization was proposed. This formulation was applied to steel seismic loads. The multi-objective optimization problem was formulated with minimum structural weight, maximum strstability. The global criterion method was employed to find a rational solution closest to the ideal solution for the optimization problem using standard steel profile, To efficiently solve the optimization problem, the decomposition meth both system-level and element-level was used. In addition, various techniques including efficient reanalysis technique intermediate variables and sensitivity analysis using an automatic differentiation(AD) were incorporated. Moreover the reamong section properties fitted to the section profile used in order to link the system level and the element level. From numerical investigation, it could be stated that the proposed method will lead to the more rational design compared with one.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.637-637
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• 2012

본 연구에서는 내수침수 저감을 위하여 효율적(effective)인 우수저류조 설치에 따른 침수저감효과 극대화 방안을 제시하고자 한다. 여기서 효율성(effectiveness)은 침수저감량의 극대화 측면과 비용의 최소화 측면 두 가지로 구분된다. 최적 방재 시설물의 설치는 단순 설치비용 대비 저감량이 가장 큰 안을 제시하는 것은 의미가 없으며 일정 기준 이상의 방재성능을 발휘하면서 주어진 예산안에서 최적안을 찾아야 하므로 비용의 최소화 측면과 침수 저감량, 즉 맨홀에서의 월류 저감량을 최대화 하는 두 가지의 목적을 동시에 달성해야 한다. 따라서 본 연구에서는 다목적 최적화 알고리즘의 적용을 통하여 우수저류조 최적 설치지점을 선정하는 기법을 제안하였다. 본 연구에 적용한 다목적 최적화 방법으로는 목적함수의 최적해 탐색 효용성 측면에서 우수하다고 평가되고 있는 유전자 알고리즘을 적용하였다. 다목적 최적화의 경우 해의 우열을 판단하기 위한 적합도 함수는 실제 각 목적함수의 적합도 값(real fitness value)이 아닌 해의 상대적인 우열(dominance or non-dominance)에 따라 부여되는 등급(rank)에 의해서 해의 우열이 결정되며 여기서는 Fonseca and Fleming(1993)이 제안한 Ranking method를 적용하여 적합도를 결정하였다. 한편 도시 우수관망의 해석 및 우수저류조 설치에 따른 월류량 분석을 위하여 미 환경청(US Environmental Protection Agency; EPA)에서 제공하고 있는 EPA-SWMM 5.0 engine을 사용하였으며 최적화 알고리즘의 구성을 위하여 Visual C++와 SWMM DLL을 연동하여 사용하였다. 연구 대상유역은 인천 청라지구(3공구)를 대상으로 기법의 적용성을 검토하였으며 저류지 설치에 따른 비용함수는 EPA(2002)에서 제안한 저류지 체적대비 공사비용을 원화로 환산한 후 청라지구의 공시지가를 고려하여 결정하였다. 최적화 기법의 적용 결과 저류지 설치비용에 따라 최대로 월류량을 저감시킬 수 있는 우수저류조 최적 설치위치의 조합(Pareto-front)을 결정할 수 있었다.