• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.6
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• pp.301-308
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• 2018

This paper presents an optimal design method of a hybrid structural control system considering multi-hazard. Unlike a typical structural control system in which one system is designed for one specific type of hazard, a simultaneous optimal design method for both active and passive control systems is proposed for the mitigation of seismic and wind induced vibration responses of structures. As a numerical example, an optimal design problem is illustrated for a hybrid mass damper(HMD) and 30 viscous dampers which are installed on a 30 story building structure. In order to solve the optimization problem, a self-adaptive Harmony Search(HS) algorithm is adopted. Harmony Search algorithm is one of the meta-heuristic evolutionary methods for the global optimization, which mimics the human player's tuning process of musical instruments. A self-adaptive, dynamic parameter adjustment algorithm is also utilized for the purpose of broad search and fast convergence. The optimization results shows that the performance and effectiveness of the proposed system is superior with respect to a reference hybrid system in which the active and passive systems are independently optimized.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.234-236
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• 2003

본 논문에서는 Tabu 탐색법을 이용하여 UPFC용 퍼지 댐핑 제어기를 설계하였다. 또한 UPFC가 장착된 1기 무한대 계통에 대한 Dynamic 모델을 유도하였고, 기존에 순차적인 해석 방법의 문제점을 해결하였다. 경험적 최적화알고리즘인 Tabu 탐색법을 이용하여 UPFC용 퍼지 댐핑 제어기의 입 출력 이득을 튜닝하였다. 제안한 방법의 유용성을 입증하기 위해 1기 무한대 계통에 적용하여 비선형 시뮬레이션을 수행하였다. 이때 설계한 UPFC용 퍼지 댐핑 제어기는 사례계통의 운전 조건에 대해서 기존의 제어기보다 더 나은 제어 성능을 나타내었다.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.36.4-36.4
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• 2010

이 논문에서는 신호감시국, 상향링크국, 감시제어 시스템으로 구성된 위성항법 지상국과 탐색구조단말기 관련 기술내용과 그 시험에 대한 내용을 기술하였다. 위성항법 지상국 시스템 및 탐색구조 단말기 기술 개발은 향상된 위치기반서비스와 재난시 신속한 탐색구조 서비스 제공을 위한 것으로 그 핵심기술 개발을 주요 목적으로 한다. 이를 통하여 개발된 신호감시국용 고정밀 위성항법 수신기 기술은 고정밀 전문용 위성항법 단말기의 상용화의 추진하며 감시제어시스템은 GPS 및 갈릴레오 신호 감시 데이터를 위성항법 통제센터(GNSS Control Center: GCC)에 제공하고, 향상된 위치 정확도를 제공하며, 위성항법 신호감시국의 장비를 감시 제어하며, GPS 및 갈릴레오 서비스를 위한 가용성을 제공하는 것이다. 상향링크국에서는 다중 중궤도 위성 추적시스템과 상향링크 데이터 처리를 목적으로 한다. 탐색구조 단말기 기술개발은 항법 칩셋을 탑재한 2세대 탐색구조 단말기를 개발 완료 함으로써 신속하고 정확한 조난구조가 가능하게 하는 단말기를 국내외 시장에 내놓을 수 있게 하였으며, 2세대 탐색구조 단말기의 소형화 저전력화에 성공하여 상용화 및 국제인증을 완료하였다. 이 논문에서는 이러한 기술개발 내용과 그검증을 위한 시험 결과에 대하여 소개하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.475-481
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• 2013

The control system of a direct drive servo valve is a nonlinear system, and the flow force effect on the spool motion is significant and dependent on the load pressure. To satisfy the control system design requirements, the optimal parameters of the lead-lag controller and the derivative feedback controller are searched for using a genetic algorithm and a complex constrained direct search type method. The obtained controller parameters successfully perform their role to satisfy the control system design requirements.

• Journal of IKEEE
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• v.25 no.3
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• pp.437-444
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• 2021

In this paper, we propose an autonomous driving algorithm that allows a robot to explore various terrains, and implement an application that can monitor the robot's movement path during terrain search. The implemented application consists of a status unit that indicates the position, direction, speed, and motion of the mobile robot, a map unit that displays terrain information obtained through terrain search, and a control unit that controls the movement of the mobile robot. In order to control the movement of the robot, only the start and stop of the search/return is commanded by the application, and all driving for the search is performed autonomously. The basic algorithm for terrain search uses an infrared sensor to check for obstacles in the order of left, front, right, and rear, and if there is no obstacle and the path traveled is a dead end, it returns to the previous position and moves in the other direction to continue the search. Repeat the process to explore the terrain.

• Journal of Korean Society of Transportation
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• v.21 no.1
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• pp.103-113
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• 2003

This paper shows alternative route search and preference route search for the traffic route search, and proposes the use of the fuzzy non-additive controller by the application of AHP(analytic hierarchy process). It is different from classical route search and notices thinking method of human. Appraisal element, weight of route is extracted from basic of the opinion gathering for the driving expert and example of route model was used for the finding of practice utility. Model evaluation was performed attribute membership function making of estimate element, estimate value setting, weight define by the AHP, non additive presentation of weight according to $\lambda$-fuzzy measure and Choquet fuzzy integral. Finally, alternative route search was possible to real time traffic route search for the well variable traffic environment, and preference route search showed reflection of traffic route search disposition for the driver individual. This paper has five important meaning. (1)The approach is similar to the driver's route selection decision process. (2)The approach is able to control of route appraisal criteria for the multiple attribute. (3)The approach makes subjective judgement objective by a non additive. (4)The approach shows dynamic route search for the alternative route search. (5)The approach is able to consider characteristics of individual drivers attributed for the preference route search.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.1
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• pp.62-66
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• 2011

This paper proposes a parallel architecture of random signal-based learning (PRSL), merged with simulated annealing (SA), to optimize the fuzzy logic controller (FLC). Random signal-based learning (RSL) finds the local optima very well, whereas it can not finds the global optimum in a very complex search space because of its serial nature. To overcome these difficulties, PRSL, which consists of serial RSL as a population, is considered. Moreover, SA is added to RSL to help the exploration. The validity of the proposed algorithm is conformed by applying it to the optimization of a FLC for the inverted pendulum.

• ICROS
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• v.8 no.3
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• pp.14-21
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• 2002

• Journal of Energy Engineering
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• v.12 no.1
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• pp.42-48
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• 2003

In system planing and operation, voltage and reactive power control is very important. The voltage deviation and system losses can be reduced through control of reactive power sources. In general, there are several different reactive power sources, we used switched shunt capacitor to improve the voltage profile and to reduce system losses. Since there are many switched shunt capacitors in power system, so it if necessary to coordinate these switched shunt capacitors. In this study, Genetic Algorithm (GA) is used to find optimal coordination of switched shunt capacitors in a local area of power system. In case study, the effectiveness of the proposed method is demonstrated in KEPCO's power system. The simulation is performed by PSS/E and the results of simulation are compared with sensitivity method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2533-2540
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• 2013

In multihop cellular network environments, the mobility of nodes is a major obstacle to find a reliable routing path between a mobile node (MN) and the access node (AN). Therefore, in this paper, we propose a fast and reliable neighbor discovery protocol that enables the fast and reliable neighbor discovery by considering the node mobility in the multihop cellular network. The proposed neighbor discovery protocol inhibits the transmission of unnecessary control messages to quickly find a suitable neighbor node (NN) and performs a priority-based access control to transmit control messages without collision in the order of NN desirable to be selected. Simulation results show that the proposed neighbor discovery protocol can discover the NNs faster than the conventional scheme and select a more reliable relay node although the number of neighbor nodes increases and the node mobility increases.