• 한국수자원학회논문집
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• 제43권10호
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• pp.893-909
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• 2010

지하수의 지속가능개발량을 산정하기 위해서는 유역 내에서 지하수 개발에 따라 시공간적으로 끊임없이 변화하는 하천과 대수층의 상호흐름을 포함한 물 순환계의 유동을 모의하여야 한다. 유역 단위의 지하수 함양 및 하천-대수층 상호흐름 특성을 모의하기 위한 강우-유출모형으로 탱크모형과 SWMM 모형을 선정하였다. 토양저류구조 표준3단 탱크모형을 하천과 대수층의 상호흐름을 모의할 수 있도록 개선하였다. 오차의 비등분산성을 고려하기 위한 분산함수를 가진 최우도추정법을 적용하고, 전역 최적화 기법인 Simulated Annealing 방법을 적용하여 탱크모형과 분산함수의 매개변수를 동시에 추정하였다. 하천-대수층 상호흐름을 개선한 SWMM-GE모형은 도시하천에 적용되어 검증을 받은바 있다. 금강의 지류인 갑천 유역에 하천-대수층 상호흐름을 개선한 탱크모형(TANK_GS)을 적용한 결과 개선 전 보다 모형성능평가가 더 나았으며, SWMM-GE 모형과 동일하게 지하수 함양 및 하천-대수층 상호흐름 현상을 잘 모의하고 있었다. 향후 권역 수자원 계획 등에 활용이 용이한 탱크모형(TANK_GS)을 이용하여 지하수의 지속가능 개발량 산정이 가능하다.

• 한국전산구조공학회논문집
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• 제25권1호
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• pp.51-56
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• 2012

회전익 항공기에 광범위하게 적용되고 있는 내충격성 연료셀은 항공기 추락 시 탑승자의 생존성 향상에 크게 기여하고 있다. 미육군에서는 항공기 추락 후 화재에 의한 인명손실을 원천적으로 방지하기 위해 군용 회전익기 역사의 초기 단계부터 연료셀 고유의 내충격성에 관련된 군사규격을 제정하여 적용해 왔다. 국외 전문제작 업체들은 장기간의 경험에 의존하여 연료셀을 개발하고 있으며, 충돌충격시험에 따른 시행착오의 결과를 설계 및 제작과정에 재반영하고 있다. 이러한 연료셀 충돌충격시험은 시편자체의 제작비용 및 준비기간이 상당히 소요되므로, 설계 초기단계부터 충돌충격시험에 대한 일련의 수치적 모사를 통해 실물에 의한 시행착오의 가능성을 최소화해야 한다. 본 연구에서는 충돌모사 프로그램인 Autodyn으로 연료셀 충돌충격시험에 대한 다수의 수치해석을 수행, 등가응력 분석을 통해 적절한 설계변수를 선정하였다. 또한 인공신경망과 모의풀림 방법을 연동시켜 연료셀 형상을 내충격성능 측면에서 최적화하였다.

• 한국의학물리학회지:의학물리
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• 제13권4호
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• pp.181-186
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• 2002

세기조절 방사선 치료는 각각의 치료계획 시스템의 도스 최적화 알고리즘과 선형 가속기의 조합에 따라 다양하게 최적의 성능을 발휘 할 수 있다. 연세 암센터는 효과적인 방사선치료를 위하여 2002년 2월에 세기조절 방사선 치료 시스템을 도입하여 운영 중에 있으며 도입된 시스템은 CORVUS (Nomos, 미국) 치료계획 시스템과 LANTIS, PRIMEVIEW, PRIMART (Siemens, 미국)의 선형가속기 시스템으로 구성되어 있다. 최적화된 치료를 위해서는 CORVUS 치료계획기와 PRIMART 선형가속기의 적절한 조합 조건을 찾아 적용하는 것이 중요한 일이다. 이 Step ＆ Shoot 방식의 세기조절 방사선 치료기는 Finite Size Pencil Beams (FSPB) 도스모델과 simulated annealing method의 도스 최적화 알고리즘 및 IMFAST의 segmentation 알고리즘을 사용하고 있다. 본 연구는 segmentation 알고리듬에 관한 것으로 두개의 기본 beamlet 크기(1.0$\times$1.0 $\textrm{cm}^2$ 와 0.5$\times$1.0$\textrm{cm}^2$)와 4가지의 빔 세기 단계(5%, 10%, 20%, 33%)의 option을 4명의 상이한 환자 case에 대하여 적용하고 비교해 보았다. 상대적으로 작은 target 부피를 갖는 경우 TPS상의 segmentation의 설정에 민감하게 target 도스분포가 변하였으며 작은 beamlet일수록 intensity step을 작게 할수록 최적의 도스분포를 보여주었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.844-847
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• 1997

In this paper, scheduling problem is dealt for the minimization of due date penalty for the customer order. Multiproduct batch processes have been dealt with for their suitability for high value added low volume products. Their scheduling problems take minimization of process operation for objective function, which is not enough to meet the customer satisfaction and the process efficiency simultaneously because of increasing requirement of fast adaptation for rapid changing market condition. So new target function has been suggested by other researches to meet two goals. Penalty function minimization is one of them. To present more precisely production scheduling, we develop new scheduling model with penalty function of earliness and tardiness We can find many real cases that penalty parameters are divergent by the difference between the completion time of operation and due date. That is to say, the penalty parameter values for the product change by the customer demand condition. If the order charges different value for due date, we can solve it with the due date period. The period means the time scope where penalty parameter value is 0. If we make use of the due date period, the optimal sequence of our model is not always same with that of fixed due date point. And if every product have due date period, due date of them are overlapped which needs optimization for the maximum profit and minimum penalty. Due date period extension can be enlarged to makespan minimization if every product has the same abundant due date period and same penalty parameter. We solve this new scheduling model by simulated annealing method. We also develop the program, which can calculate the optimal sequence and display the Gantt chart showing the unit progress and time allocation only with processing data.

• 한국수자원학회논문집
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• 제38권12호
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• pp.1061-1072
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• 2005

본 연구에서는 영산호의 상류에 위치한 나주유역의 홍수시 유출량을 실시간으로 예측하기 위하여 Grey홍수 유출모형을 개발하였다. 나주유역의 유출량은 나주수위관측소에서 실시간으로 측정하고 있으며, 이곳은 영산호의 유입홍수량을 예측과 홍수관리를 위한 주관측소이다. 모형의 지배방정식은 Grey시스템 이론에 근거하여 구성되었으며, 모형의 매개변수는 Grey 시스템매개변수의 조합으로 구성하였다. 모형의 차수는 실측자료와 모의결과를 비교하여 다른 차수 보다 양호한 결과를 나타내는 5차로 하였다. 모형의 보정시 예측결과와 실측치간의 RMSE는 $3.1\~290.5m^{3}/sec$를 나타냈으며, $R^{2}$는 $0.909\~0.999$를 나타냈다. 모형의 검정시 예측결과와 실측치간의 RMSE는 $20.6\~147.4m^{3}/sec$를 나타냈으며, $R^{2}는\;0.940\~0.998$를 나타냈다. 매개변수가 추정된 모형을 이용하여 담수호의 유입량을 하천수위 상태에 따라 예측한 결과, 하천수위가 상승할 경우와 하강할 경우의 예측 홍수량은 예측시간이 증가할수록 커지는 경향을 나타냈다. 또한, 하천수위가 첨두에 가까운 시기의 홍수량은 예측시간에 관계없이 실측자료와 비슷한 결과를 나타냈다. 이와 같은 결과는 Grey 홍수유출모형을 홍수시 담수호 유입량을 실시간으로 정확하게 예측하는데 적용할 수 있음을 나타낸다.

• 대한조선학회논문집
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• 제54권3호
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• pp.187-195
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• 2017

The operation planning of transports used to move blocks is the one of key factors. Furthermore, reducing the running time through the effective plan contributes to pulling forward the whole logistic process of the shipyard and substantially saving the fuel consumption of itself as well. The past researches of the transporter focused on finding only the shortest distances, so called, Manhattan distance. However, these searching approaches cannot help having the significant difference in the real operational time and distance with the minimum cost approach which considers the speed retardation for turns or safety at the intersection. This study suggests the noble transporter's operational model which could take account of the consuming operational time around the crossroads on the shipyard. Concretely, the proposed method guarantees the minimization of transporters' turns and passage number which are huge burdensome to the operation time and the whole planning of transports with the given period. Resultantly, this paper is willing to explain the appropriateness of our approach, compared with the previous ones.

• 한국소음진동공학회논문집
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• 제13권10호
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• pp.743-750
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• 2003

The equivalent source method(ESM) is used for the calculation of the internal pressure field for an enclosure which can have arbitrary boundary conditions and nay include internal objects which scatter the sound field. The advantage of using ESM is that it requires relatively low computing cost and is easy to model the internal diffracting objects. Typical ESM modeling uses two groups of equivalent source positions. One group includes the first order images of the source inside the enclosure. The Positions of the other group are usually on a spherical surface some distance outside the enclosure. The normal velocity on the surfaces of the enclosure walls is evaluated at a larger number of positions than there are equivalent sources. The sum of the squared difference between this velocity and the expected is minimized by adjusting the strength of the equivalent sources. This study is on the optimal far field sources positions when using the equivalent source method. In general, the far field sources are evenly distributed on a surface of a virtual sphere which is centered at the enclosure with a sufficiently large radius. In this study. optimal far field source locations are searched using simulated annealing method for various radii of spheres where far field sources are located. Simulation results showed that optimally located sources with adequate distance away from the enclosure center gave better result than sources with even distribution even with a smaller number of far field sources.

• 음성과학
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• 제10권4호
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• pp.7-21
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• 2003

Sums-of-Products models were built for segment duration prediction of spoken Korean. An experiment for the modelling was carried out to apply the results to Korean text-to-speech synthesis systems. 670 read sentences were analyzed. trained and tested for the construction of the duration models. Traditional sequential rule systems were extended to simple additive, multiplicative and additive-multiplicative models based on Sums-of-Products modelling. The parameters used in the modelling include the properties of the target segment and its neighbors and the target segment's position in the prosodic structure. Two optimisation strategies were used: the downhill simplex method and the simulated annealing method. The performance of the models was measured by the correlation coefficient and the root mean squared prediction error (RMSE) between actual and predicted duration in the test data. The best performance was obtained when the data was trained and tested by ' additive-multiplicative models. ' The correlation for the vowel duration prediction was 0.69 and the RMSE. 31.80 ms. while the correlation for the consonant duration prediction was 0.54 and the RMSE. 29.02 ms. The results were not good enough to be applied to the real-time text-to-speech systems. Further investigation of feature interactions is required for the better performance of the Sums-of-Products models.

• 대한기계학회논문집A
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• 제27권5호
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• pp.798-806
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• 2003

Structural optimization has been carried out in continuous or discrete design space. Methods for continuous design have been well developed though they are finding the local optima. On the contrary, the existing methods for discrete design are extremely expensive in computational cost or not robust. In this research, an algorithm using tabu search is developed fur the discrete structural designs. The tabu list and the neighbor function of the Tabu concepts are introduced to the algorithm. It defines the number of steps, the maximum number for random searches and the stop criteria. A tabu search is known as the heuristic approach while genetic algorithm and simulated annealing algorithm are attributed to the stochastic approach. It is shown that an algorithm using the tabu search with random moves has an advantage of discrete design. Furthermore, the suggested method finds the reliable optimum for the discrete design problems. The existing tabu search methods are reviewed. Subsequently, the suggested method is explained. The mathematical problems and structural design problems are investigated to show the validity of the proposed method. The results of the structural designs are compared with those from a genetic algorithm and an orthogonal array design.

• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2166-2176
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• 2017

Electricity price prediction plays a crucial part in making the schedule and managing the risk to the competitive electricity market participants. However, it is a difficult and challenging task owing to the characteristics of the nonlinearity, non-stationarity and uncertainty of the price series. This study proposes a hybrid improved strategy which incorporates data preprocessor components and a forecasting engine component to enhance the forecasting accuracy of the electricity price. In the developed forecasting procedure, the Seasonal Adjustment (SA) method and the Ensemble Empirical Mode Decomposition (EEMD) technique are synthesized as the data preprocessing component; the Coupled Simulated Annealing (CSA) optimization method and the Least Square Support Vector Regression (LSSVR) algorithm construct the prediction engine. The proposed hybrid approach is verified with electricity price data sampled from the power market of New South Wales in Australia. The simulation outcome manifests that the proposed hybrid approach obtains the observable improvement in the forecasting accuracy compared with other approaches, which suggests that the proposed combinational approach occupies preferable predication ability and enough precision.