• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.150-155
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• 1998

Sliding mode control is a powerful control methodology for the control of uncertain systems. However, it and its variations have some disadvantages such as chattering and imprecise tracing performance. A novel scheme of the sliding mode control is presented for the accurate tracking control of the uncertain systems. The fuzzy logic-baced control law maintaining stability and consistent performance in the face of modeling imprecise is derived and simulation results showing its effectiveness are presented.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.974-976
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• 1996

In this paper, a reference model following control system using a fuzzy logic controller(FLC) is proposed By using an integrator and a nonlinear hysteresis element, a reference model whose response has no overshoot and fast rise time is designed. A FLC is designed to follow as close as possible to the response of the reference model. The proposed design method is shown that the robustness and the optimal tracking property can be achieved under modeling error, disturbance and parameter perturbations. The effectiveness of the proposed design method is verified through the simulation that compare using the FLC with using a $H_{\infty}$ controller.

• Advances in aircraft and spacecraft science
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• v.8 no.1
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• pp.69-85
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• 2021

A modified fuzzy mechanical control of large-scale multiple time delayed dynamic systems in states is considered in this paper. To do this, at the first level, a two-step strategy is proposed to divide a large system into several interconnected subsystems. As a modified fuzzy control command, the next was received as feedback theory based on the energetic function and the LMI optimal stability criteria which allow researchers to solve this problem and have the whole system in asymptotically stability. Modeling the Fisher equation and the temperature gauge for high-speed aircraft and spacecraft shows that the calculation method is efficient.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1612-1618
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• 2021

The fusion-barrier distribution is very sensitive to the structure of the colliding nuclei such as nuclear quadrupole and hexadecapole deformation parameters and their signs. If the nuclei that enter the fusion reaction are deformed, the barrier problem becomes complicated. Therefore the deformation parameters are taken into account in the calculations. In this study, Neuro-Fuzzy approach, ANFIS, method has been used for the estimation of ground-state quadrupole (𝜀₂) and hexadecapole (𝜀₄) deformation parameters for the nuclei. According to the results, the method is suitable for this task and one can confidently use it to obtain the data that is not available in the literature.

• Steel and Composite Structures
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• v.47 no.4
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• pp.513-521
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• 2023

The goal of this work is to create a new and improved GWO (Grey Wolf Optimizer), the so-called Robot GWO (RGWO), for dynamic and static target tracking involving multiple robots in unknown environmental conditions. From applying ourselves with the Gray Wolf Optimization Algorithm (GWO) and how it works, as the name suggests, it is a nature-inspired metaheuristic based on the behavior of wolf packs. Like other nature-inspired metaheuristics such as genetic algorithms and firefly algorithms, we explore the search space to find the optimal solution. The results also show that the improved optimal control method can provide superior power characteristics even when operating conditions and design parameters are changed.

• Journal of Korea Water Resources Association
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• v.45 no.2
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• pp.229-242
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• 2012

This study presents a physical habitat modeling of adult Zacco platypus in a reach of the Dalcheon Stream located downstream of the Goesaan Dam. CASiMiR model is used to estimate habitat suitability index based on the fuzzy logic. Results are compared with those from River2D model, which uses habitat preference curve for habitat suitability index. Hydraulic data simulated by River2D are used as input data for CASiMiR model after verification against field measurements. The result shows that the habitat suitability of the adult Zacco platypus is maximum around the riffle area located upstream of the bend. CASiMiR and River2D estimate the maximum weighted usable areas at the discharge rates of 7.23 $m^3/s$ and 9.0 $m^3/s$, respectively. Overall comparison of the two models employed in this study indicates that CASiMiR model overestimates the weighted usable area by 0.3~25.3% compared with River2D model in condition of drought flow (Q355), low flow (Q275), normal flow (Q185), and average-wet flow (Q95).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5B
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• pp.405-414
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• 2011

The adaptive network-based fuzzy inference system (ANFIS) which had a success for time series prediction and system control was applied for modeling the hourly runoff in the Gapcheon watershed. The ANFIS used the antecedent rainfall and runoff as the input. The ANFIS was trained by varying the various simulation factors such as mean areal rainfall estimation, the number of input variables, the type of membership function and the number of membership function. The root mean square error (RMSE), mean peak runoff error (PE), and mean peak time error (TE) were used for validating the ANFIS simulation. The ANFIS predicted runoff was in good agreement with the measured runoff and the applicability of ANFIS for modelling the hourly runoff appeared to be good. The forecasting ability of ANFIS up to the maximum 8 lead hour was investigated by applying the different input structure to ANFIS model. The accuracy of ANFIS for predicting the hourly runoff was reduced as the forecasting lead hours increased. The long-term predictability of ANFIS for forecasting the hourly runoff at longer lead hours appeared to be limited. The ANFIS might be useful for modeling the hourly runoff and has an advantage over the physically based models because the model construction of ANFIS based on only input and output data is relatively simple.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.2
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• pp.218-224
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• 2012

Recently, as the needs of developing the micro autonomous underwater vehicle (AUV) are increasing, the acquisition of the elementary technology is urgent. While they mostly utilizes information of the forward looking sonar (FLS) in conventional studies of the local path control as an elementary technology, it is desirable to use the obstacle avoidance sonar (OAS) because the size of the FLS is not suitable for the micro AUV. In brief, the local path control system based on the OAS for the micro AUV operates with the following problems: the OAS offers low bearing resolution and local range information, it requires the system that has reduced power consumption to extend the mission execution time, and it requires an easy design procedure in terms of its structures and parameters. To solve these problems, an intelligent local path control algorithm based on the beam modeling of OAS with the evolution strategy (ES) and the fuzzy logic controller (FLC), is proposed. To verify the performance and analyze the characteristic of the proposed algorithm, the course control of the underwater flight vehicle (UFV) is performed in the horizontal plane. Simulation results show that the feasibility of real application and the necessity of additional work in the proposed algorithm.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.228-237
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• 2021

In those day, the Busan local government had instituted a rule to support and enhance competition as well as improve respect for the ship management industry. This study aims to extract the cause factors to enhance such competition using intuitionistic decision making trial and evaluation laboratory (DEMATEL) and interpretive structural modeling (ISM) methods. First, eight factors were extracted from the specifications in the Ship Management Industry Development Act. Second, the intuitionistic fuzzy number was converted to a crisp number using the standard fuzzy number. Third, the influence relationship was analyzed using DEMATEL, and the priority ranks for the factors are determined using ISM. From the results of the impact relationship analysis, the three main cause factors were determined as improvement of technical ship management capability, improvement of expertise of manpower for onshore management, and improvement of the quality of the Korean seafarer. The priorities under the ISM method, in descending order, were as follows: improvement of the quality of Korean seafarers, improvement of professionalism among the manpower for shore management, improvement of technical ship management capability, improvement of commercial ship management capability, establishment of a comprehensive information system, improvement of the working conditions and employment environment for seafarers, financial support such as overseas orders, and strengthening the availability of foreign seafarers. Therefore, it is necessary to prioritize policy promotion based on these factors, especially the top three, as these have the highest impact.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.4
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• pp.359-365
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• 2001

In this paper, we propose the design methodology of target tracking system using fuzzy basis function expansion(FBFE) based on virus evolutionary genetic algorithm (VEGA). In general, the objective of target tracking is to estimate the future trajectory of the target based on the past position of the target obtained from the sensor. In the conventional and mathematical nonlinear filtering method such as extended Kalman filter(EKF), the performance of the system may be deteriorated in highly nonlinear situation. To resolve these problems of nonlinear filtering technique, by appling artificial intelligent technique to the tracking control of moving targets, we combine the advantages of both traditional and intelligent control technique. In the proposed method, after composing training datum from the parameters of extended Kalman filter, by combining FDFE, which has the strong ability for the approximation, with VEGA, which prevent GA from converging prematurely in the case of lack of genetic diversity of population, and by idenLifying the parameters and rule numbers of fuzzy basis function simultaneously, we can reduce the tracking error of EKF. Finally, the proposed method is applied to three dimensional tracking problem, and the simulation results shows that the tracking performance is improved by the proposed method.