• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.446-452
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• 2008

To design a spiral inductor a genetic algorithm is applied with fast computing technique. For the inductance extraction of the given geometry the fast multipole method is used, also the distributed computing technique using 10 personal computers is introduced for the massive computation of the genetic algorithm. A few important design parameters are used as genes for the optimization in the genetic algorithm. The target function is chosen as mean square error of the inductance at several sampling frequency points. A large-scaled inductor is fabricated and compared with the simulated data.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.5
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• pp.52-65
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• 1997

For the degradation of severe noise and ill-conditioned blur the optimization function has the solution spaces which have many local optima around global solution. General restoration methods such as inverse filtering or gradient methods are mainly dependent on the properties of degradation model and tend to be isolated into a local optima because their convergences are determined in the convex space. Hence we introduce genetic algorithm as a searching method which will search solutions beyond the convex spaces including local solutins. In this paper we introudce improved evaluation square error) and fitness value for gray scaled images. Finally we also proposed the local fine tunign of window size and visit number for delicate searching mechanism in the vicinity of th global solution. Through the experiental results we verified the effectiveness of the proposed genetic operators and evaluation function on noise reduction over the conventional ones, as well as the improved performance of local fine tuning.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.233-236
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• 2007

A new evolution method for strong exploration and strong exploitation termed queen-bee and mutant-bee evolution is proposed based on the previous queen-bee evolution [1]. Even though the queen-bee evolution has shown very good performances, two parameters for strong mutation are added to the genetic algorithms. This makes the application of genetic algorithms with queen-bee evolution difficult because the values of the two parameters are empirically decided by a trial-and-error method without a systematic method. The queen-bee and mutant-bee evolution has no this problem because it does not need additional parameters for strong mutation. Experimental results with typical problems showed that the queen-bee and mutant-bee evolution produced nearly similar results to the best ones of queen-bee evolution even though it didn't need to select proper values of additional parameters.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.358-363
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• 2003

Optimal tuning plays an important role in operations or tuning of the complex process such as the main steam temperature of the thermal power plant. However, it is very difficult to maintain the steam temperature of power plant using conventional optimization methods, since these processes have the time delay and the change of the dynamic characteristics in the reheater. Up to the present time, the Pm controller has been used. However, it is not easy to achieve an optimal PID gain with no experience, since the gain of the PID controller has to be manually tuned by trial and error. This paper suggests immune algorithm based tuning technique for PID Controller on steam temperature process with long dead time and its results are compared with genetic algorithm based tuning technique.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.525-530
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• 2003

This paper focuses on design of nonlinear power plant controller using immune based multiobjective fuzzy approach. The thermal power plant is typically regulated by the fuel flow rate, the spray flow rate, and the gas recirculation flow rate. However, Strictly maintaining the steam temperature can be difficult due to heating value variation to the fuel source, time delay changes in the main steam temperature. the change of the dynamic characteristics in the steam-turbine system. Up to the present time, PID Controller has been used to operate this system. However, it is very difficult to achieve an optimal PID gain with no experience, since the gain of the PID controller has to be manually tuned by trial and error. These parameters tuned by multiobjective based on immune network algorithms could be used for the tuning of nonlinear power plant.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.459-462
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• 2003

Selectivity estimation of queries not only provides useful information to the query processing optimization but also may give users with a preview of processing results. In this paper, we investigate the problem of selectivity estimation in the context of a spatial dataset. Although several techniques have been proposed in the literature to estimate spatial query result sizes, most of those techniques still have some drawback in the case that a large amount of memory is required to retain accurate selectivity. To eliminate the drawback of estimation techniques in previous works, we propose a new method called MW Histogram. Our method is based on two techniques: (a) MinSkew partitioning algorithm that processes skewed spatial datasets efficiently (b) Wavelet transformation which compression effect is proven. We evaluate our method via real datasets. With the experimental result, we prove that the MW Histogram has the ability of providing estimates with low relative error and retaining the similar estimates even if memory space is small.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2001.11b
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• pp.77-81
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• 2001

본 논문은 현재 국내 디지털 오디오 방송의 잠정 표준으로 채택된 Eureka-147 시스템에서의 멀티미디어 전송 프로토콜 규약인 MOT(Multimedia Object Transfer) 프로토콜을 적용하여 멀티미디어 파일을 전송할 경우의 성능 분석 및 파라미터 최적화 방법을 제시하였다. MOT 프로토콜은 멀티미디어 파일을 전송하는 세그먼트 크기, 세그먼트 반복횟수와 같은 파라미터 설정값에 따라서 FER(File Error Ratio)이 변화하므로, 성능을 최적화하기 위한 파라미터 설정이 중요하다. 세그먼트 내에서 비트 사이의 오류 사건이 독립이라는 가정하에서 MOT 파라미터 설정값을 찾는 이론적 수식을 제안하였고, 이동 채널 환경의 시뮬레이션을 통하여 이론식과 비교하였다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.3-7
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• 2006

Indoor localization is getting more and more importance with the increasing demand for location based service. Location based service necessarily requires the information about customers' locations to provide them the right service according to their changing locations. To satisfy that requirement, GPS is used to achieve outdoor localization. However, there is no leading technology to achieve indoor localization. Indoor localization through UWB wave and TDOA algorithm is considered as the most accurate method until now. In implementing that method, configuration of base stations that serve as control points affects the localization accuracy. Thus, this paper discusses about optimal configuration of base stations. The variation in localization accuracy according to spatial relationship between an object and base stations Is mentioned through SEP also.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.861-869
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• 2012

The chlorine's residual concentration prevents the regrowth of microorganism in water transport along the pipeline system. Precise prediction of chlorine concentration is important in determining disinfectant injection for the water distribution system. In this study, a pilot scale water distribution system was designed and fabricated to measure the temporal variation of chlorine concentration for three flow conditions (V = 0.88, 1.33, 1.95 m/s). Various kinetic models were applied to identify the relationship between hydraulic condition and chlorine decay. Genetic Algorithm (GA) was integrated into five kinetic models and time series of chlorine were used to calibrate parameters. Model fitness was compared by Root Mean Square Error (RMSE) between measurement and prediction. Limited first order model and Parallel first order showed good fitness for prediction of chlorine concentration.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.731-736
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• 2005

현재 국내 주요 하천의 홍수예경보시스템 운영과 다목적댐의 홍수조절관리를 위하여 수문학적 모형의 하나인 저류함수모형(Storage Function Model)을 사용하고 있다. 저류함수모형은 산지가 많은 유역에 적합하도록 개발된 모형으로, 계산절차가 간편하고 홍수유출의 비선형성을 고려할 수 있는 방법이므로 선형모형보다 합리적이라고 알려져 있다. 그러나 저류함수모형을 실제 홍수유출현상에 적용하는데 있어 매개변수를 결정하는 것이 매우 어렵다. 현재 매개변수들을 결정할 수 있는 객관적이고 합리적인 방법이 제시되어 있지 않기 때문에 모형의 매개변수를 결정할 때 경험식을 이용하거나 수문기술자의 판단에 의한 보정에 의존하고 있다. 따라서, 본 논문에서는 홍수통제소에서 사용하고 있는 저류함수 모형의 대표(평균) 매개변수와 경험식, 시행착오법(trial & error method) 및 최적화기법(optimization technique) 중에 Rosenbrock 방법을 이용하여 매개변수를 산정하고 이들을 비교 분석하고자 한다.