• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 Asia Navigation Conference
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• pp.123-128
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• 2006

This paper presents the design of a surveillance night vision system for marine ships. Both a hardware system and software modules for tracking control are developed. In order to control each control axis with compensation for ship motion, the two-degree of freedom(TDF) PID controller is designed and its parameters are tuned using a real-coded genetic algorithm(RCGA). Simulation demonstrates the effectiveness of the proposed system.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.612-620
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• 2006

This paper proposes an optimal trajectory generation method for biped robots for walking up-and-down stairs using a Real-Coded Genetic Algorithm (RCGA). The RCGA is most effective in minimizing the total consumption energy of a multi-dof biped robot. Each joint angle trajectory is defined as a 4-th order polynomial of which the coefficients are chromosomes or design variables to approximate the walking gait. Constraints are divided into equalities and inequalities. First, equality constraints consist of initial conditions and repeatability conditions with respect to each joint angle and angular velocity at the start and end of a stride period. Next, inequality constraints include collision prevention conditions of a swing leg, singular prevention conditions, and stability conditions. The effectiveness of the proposed optimal trajectory is shown in computer simulations with a 6-dof biped robot model that consists of seven links in the sagittal plane. The optimal trajectory is more efficient than that generated by the Modified Gravity-Compensated Inverted Pendulum Mode (MGCIPM). And various trajectories generated by the proposed GA method are analyzed from the viewpoint of the consumption energy: walking on even ground, ascending stairs, and descending stairs.

• 한국정밀공학회지
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• 제23권4호
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• pp.75-82
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• 2006

In this paper, we propose an optimal trajectory for biped robots to move up-and-down stairs using a genetic algorithm and a computed-torque control for biped robots to be dynamically stable. First, a Real-Coded Genetic Algorithm (RCGA) which of operators are composed of reproduction, crossover and mutation is used to minimize the total energy. Constraints are divided into equalities and inequalities: Equality constraints consist of a position condition at the start and end of a step period and repeatability conditions related to each joint angle and angular velocity. Inequality constraints include collision avoidance conditions of a swing leg at the face and edge of a stair, knee joint conditions with respect to the avoidance of the kinematic singularity, and the zero moment point condition with respect to the stability into the going direction. In order to approximate a gait, each joint angle trajectory is defined as a 4-th order polynomial of which coefficients are chromosomes. The effectiveness of the proposed optimal trajectory is shown in computer simulations with a 6-dof biped robot that consists of seven links in the sagittal plane. The trajectory is more efficient than that generated by the modified GCIPM. And various trajectories generated by the proposed GA method are analyzed in a viewpoint of the consumption energy: walking on even ground, ascending stairs, and descending stairs.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.423-432
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• 2014

Non-dominated Sorting Genetic Algorithm-II (NSGA-II) is applied for solving Combined Economic Emission Dispatch (CEED) problem with valve-point loading of thermal generators. This CEED problem with valve-point loading is a nonlinear, constrained multi-objective optimization problem, with power balance and generator capacity constraints. The valve-point loading introduce ripples in the input-output characteristics of generating units and make the CEED problem as a nonsmooth optimization problem. To validate its effectiveness of NSGA-II, two benchmark test systems, IEEE 30-bus and IEEE 118-bus systems are considered. To compare the Pareto-front obtained using NSGA-II, reference Pareto-front is generated using multiple runs of Real Coded Genetic Algorithm (RCGA) with weighted sum of objectives. Comparison with other optimization techniques showed the superiority of the NSGA-II approach and confirmed its potential for solving the CEED problem. Numerical results show that NSGA-II algorithm can provide Pareto-front in a single run with good diversity and convergence. An approach based on Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) is applied on non-dominated solutions obtained to determine Best Compromise Solution (BCS).

• 한국항해항만학회지
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• 제31권8호
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• pp.697-703
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• 2007

비선형성이 강한 컨테이너 크레인은 작업 시에 호이스트 와이어로프의 길이와 화물의 질량 변화로 인해 더욱 복잡한 동역학적 특성을 나타낸다. 이 같은 복잡한 비선형시스템을 다루기 위해 퍼지로직이 종종 사용되는데, 특히 각 퍼지 규칙의 결론부를 상태 방정식으로 표현하는 T-S 퍼지모델이 대표적인 방법이다. 본 논문에서는 T-S 퍼지모델을 이용하여 호이스트 와이어로프의 길이나, 화물의 질량이 변화하는 환경에서도 컨테이너 크레인의 동특성을 표현할 수 있는 퍼지모델을 얻는 방법을 제안한다. 이때, 퍼지모델의 소속함수 파라미터는 RCGA가 결합된 모델조정기법을 통해 최적으로 조정된다. 이렇게 구현한 퍼지모델과 컨테이너 크레인 비선형시스템의 개루프 응답을 비교하여 그 유효성을 확인한다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권6호
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• pp.1010-1016
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• 2004

In this paper, a scheme for estimating the parameters of solar cells and a NN-based emulator for predicting the maximum power point are presented. The diode model with series and shunt resistors is used to estimate parameters highly affecting its V-I characteristic curve and both a real-coded genetic algorithm and the model adjustment technique are employed. For implementing the emulator, a multi-layered neural network incorporating with the BP algorithm is used. A set of simulation works using both field data and generated data are carried out to demonstrate the effectiveness of the proposed method.

• 산업기술연구
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• 제29권B호
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• pp.9-15
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• 2009

In the case of traditional binary encoding technique, it takes long time to converge the optimal solutions and brings about complexity of the systems due to encoding and decoding procedures. However, the ROGAs (real-coded genetic algorithms) do not require these procedures, and the k-means clustering algorithm can avoid global searching space. Thus, this paper proposes a new approach by using their advantages. The proposed method constructs the multiple predictors using the optimal differences that can reveal the patterns better and properties concealed in non-stationary time series where the k-means clustering algorithm is used for data classification to each predictor, then selects the best predictor. After selecting the best predictor, the cluster centers of the predictor are tuned finely via RCGKA in secondary tuning procedure. Therefore, performance of the predictor can be more enhanced. Finally, we verifies the prediction performance of the proposed system via simulating typical time series examples.

• 한국항해항만학회지
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• 제34권2호
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• pp.117-122
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• 2010

Since fuzzy controllers are nonlinear, it is more difficult to set the controller gains and to analyse the stability compared to conventional PID controllers. This paper proposes a fuzzy PD+I controller for tracking control which uses a linear fuzzy inference(product-sum-gravity) method based on a conventional linear PID controller. In this scheme the fuzzy PD+I controller works similar to the control performance as the linear PD plus I(PD+I) controller. Thus it is possible to analyse and design an fuzzy PD+I controller for given systems based on a linear fuzzy PD controller. The scaling factors tuning scheme, another topic of fuzzy controller design procedure, is also introduced in order to fine performance of the fuzzy PD+I controller. The scaling factors are adjusted by a real-coded genetic algorithm(RCGA) in off-line. The simulation results show the effectiveness of the proposed fuzzy PD+I controller for tracking control problems by comparing with the conventional PID controllers.

• 한국항해항만학회지
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• 제33권6호
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• pp.437-442
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• 2009

대양 항행하는 거의 모든 선박에서 항해사를 지원하기 위해 선박의 회두각 유지 및 변침을 목적으로 사용되는 일반적인 자동조타기는 대부분 PID형 제어기가 장착되어 있다. 선박 자동조타기의 제어기 계수는 운항 경제성 관점에서 선박의 추진 에너지 손실량(연료소비량)으로써 평가해야 한다. 본 논문에서는 선박 자동조타기의 정량적인 평가함수를 바탕으로 추진 에너지 손실량이 최소가 되도록 자동조타기의 제어이득을 구하고자 한다. 이 때 제약조건, 즉 설계사양을 고려한 RCGA를 이용하여 제어이득의 탐색을 실시하고, 시뮬레이션을 통해 제안한 방법을 검증한다.

• 한국항해항만학회지
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• 제32권10호
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• pp.851-856
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• 2008

대규모 컨테이너항만의 건설과 함께 컨테이너 크레인의 생산성 향상으로 선박 체항시간을 단축시켜 항만의 서비스 수준을 높이려는 노력이 가속화되고 있다. 컨테이너 크레인 시스템에 가해지는 입력에 대하여 바람직한 성능을 보이도록 설계사양을 고려한 상태 퍼드백 제어시스템을 사용한다. 컨테이너 크레인에서 측정이 까다롭거나 측정 잡음이 클 것으로 예상되는 상태 변수를 추정하는 방법으로 상태 관측기를 설계하고자 한다. 기존의 연구에서는 상태 피드백 제어시스템의 피드백 이득행렬과 상태 관측기 이득행렬을 분리하여 구하였다. 그러나 본 연구에서는 피드백 이득행렬과 상태 관측기 이득행렬을 선정함에 있어 최근 강인한 탐색법으로 많이 사용되는 REGAs를 사용해 설계사양을 만족하도록 동시에 구하고자 한다.