• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.2
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• pp.21-30
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• 2001

In this paper, in the power system having UPFC(Unified Power Flow Controller) Power flow of certain line is controlled to desired value also power flow analysis algorithm is reposed considering power flow constraints which is capable of analysis power flow of all system. This algorithm is applied to controlling line-overloading problems and the method of is prosed. By applying this algorithm to controlling line-over loading the method of controlling UPFC is proposed and the effectiveness of controlling UPFC is proposed and the effectiveness of controlling UPFC is verified through the research of practical system. Also, the equation to set up an initial value of stories and shunt voltage source of UPFC is proposed for the effective power analysis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.3
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• pp.39-46
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• 2005

In this paper, adaptive higher harmonic control technique using Neural Networks (NN) is proposed. First, linear transfer function is estimated to relate the input harmonics and output harmonics, then NN which has the universal function approximation property is applied to expand application range of the transfer function. Optimal control gain matrix computed from the transfer function is used to train NN weights. Online weight adaptation laws are derived from Lyapunov's direct method to guarantee internal stability. Results of the simulation of 6-input 2-output nonlinear system show that adaptive HHC is applicable to the system with uncertain transfer function.

• Journal of IKEEE
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• v.23 no.2
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• pp.628-635
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• 2019

This paper proposes sliding mode control (SMC) method for improvement of dynamic response for IPMSM based on DTC with constant switching frequency. DTC with constant switching frequency method consists of PI torque controller and triangular comparator for constant torque error status. It has the poor dynamic response compared to conventional DTC. This paper proposes improvement method of dynamic response of DTC with constant switching frequency by using SMC. Simulation results confirm the effectiveness of the proposed method.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.01a
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• pp.169-170
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• 2021

기존 신호등은 보행자를 위한 별도의 안전장치가 없다. 이는 어린아이는 물론 성인들까지 차량의 위협으로부터 안전을 보장받을 수 없다. 본 연구에서는 어린이보호구역에서 사고 발생률을 감소시키는 것을 전제로 아두이노 액추에이터와 스위치를 이용한 전자제어 신호등을 적용하고자 한다. 현재의 신호등 시스템은 단순히 시간의 흐름에 따라 보행자 신호등과 차량용 신호등의 led가 자동으로 변화하여 차량과 보행자를 통제한다. 이러한 시스템은 어린아이들의 돌발행동과 운전자의 미숙한 작동으로 인한 사고를 방지하지 못한다. 본 논문은 이러한 문제점들을 개선하기 위해 기존의 신호등 시스템 대신 스위치와 액추에이터, 초음파 센서, 블루투스 모듈을 적용한 어린이용 보호 전자제어 신호등 기술을 제안한다. 기존의 신호등 시스템과는 다르게 보행자의 직접적인 개입을 통해 시스템을 제어하고, 원활한 교통환경을 만들 수 있다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.439-440
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• 2022

대부분의 주거환경은 가전제품이나 전등 등을 수동적으로 제어하는 방식이 일반적이다. 본 연구에서는 주거환경을 스마트화함으로써 사용자의 불편함과 번거로움을 줄이고 효율적인 환경관리와 보안을 강화를 할 수 있도록 한다. 본 논문은 아두이노, 여러 센서와 블루투스모듈을 사용하여 집 내부 환경을 자동제어관리하고 사용자가 스마트폰 어플로 집 내부 환경을 파악하고 가전제품을 제어함으로써 편리함을 추구함과 동시에 에너지 절약에 도움이 될 수 있게 한다. 또한 와이파이로 연결된 카메라로 영상을 스트리밍하여 집 내부를 확인하고 대응할 수 있게 하여, 현대인의 집을 스마트하게 관리할 수 있는 "아두이노를 이용한 스마트홈"을 제안한다. 기존의 주거환경과 다르게 집 내부의 환경을 자동제어 및 환경정보를 확인하고 사용자가 직접 가전제품을 제어할 수 있으며, CCTV를 통해 집 내부를 확인 할 수 있도록 한다. 또한 화재가 감지되면 경보와 스프링클러가 작동하여 초기진압을 할 수 있다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.4
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• pp.98-106
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• 2006

This paper is proposed an efficiency optimization control algorithm for a synchronous reluctance motor which minimizes the cower and iron losses. The design of the speed controller based on adaptive fuzzy-neural networks(AFNN) controller that is implemented using fuzzy control and neural networks. There exists a variety of combinations of d and f-axis current which provide a specific motor torque. The objective of the efficiency optimization controller is to seek a combination of d and q-axis current components, which provides minimum losses at a certain operating point in steady state. It is shown that the current components which directly govern the torque production have been very well regulated by the efficiency optimization control scheme. The proposed algorithm allows the electromagnetic losses in variable speed and torque drives to be reduced while keeping good torque control dynamics. The control performance of the hybrid artificial intelligent(HAI) controller is evaluated by analysis for various operating conditions. Analysis results are presented to show the validity of the proposed algorithm

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.5
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• pp.48-55
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• 1999

This paper describes automatic gain control circuit (AGC) design techniques for CMOS CCD camera interface systems. The required gain of the AGC in the proposed system is controlled directly by digital bits without conventional extra D/A converters and the signal settling behavior is almost independent of AGC gain variation at video speeds. A capacitor-segment combination technique to obtain large capacitance values considerably improves the effective bandwidth of the AGC based on switched-capacitor techniques. A proposed layout scheme for capacitor implementation shows AGC matching accuracy better than 0.1 %. The outputs from the AGC are transferred to a 10b A/D converter integrated on the same chip. The proposed AGC is implemented as a sub-block of a CCD camera interface system using a 0.5 um n-well CMOS process. The prototype shows the 32-dB AGC dynamic range in 1/8-dB steps with 173 mW at 3 V and 25 MHz.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.5
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• pp.46-55
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• 2000

This paper presents a direct adaptive control of robot system using chaotic neural networks and PD controller. The chaotic neural networks have robust nonlinear dynamic characteristics because of the sufficient nonlinearity in neuron itself, and the additional self-feedback and inter-connecting weights between neurons in same layer. Since the structure and the learning method are not appropriate for applying in control system, this neural networks have not been applied. In this paper, a modified chaotic neural networks is presented for dynamic control system. To evaluate the performance of the proposed neural networks, these networks are applied to the trajectory control of the three-axis PUMA robot. The structure of controller consists of PD controller and chaotic neural networks in parallel for conforming the stability in initial learning phase. Therefore, the chaotic neural network controller acts as a compensating controller of PD controller.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.6
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• pp.607-614
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• 2013

Nowadays, automotive manufacturers have developed various technologies to improve fuel economy and reduce harmful emissions. The ultra-lean direct injection engine is a promising technology because it has the advantage of improving thermal efficiency through the deliberate control of fuel and ignition. This study aims to investigate the development of a spray-guided-type lean-burn LPG direct injection engine through the redesign of the combustion system. This engine uses a central-injection-type cylinder head in which the injector is installed adjacent to the spark plug. Fuel consumption and combustion stability were estimated depending on the ignition timing and injection timing at various air-fuel ratios. The optimal injection timing and ignition timing were based on the best fuel consumption and combustion stability.

• The KIPS Transactions:PartC
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• v.17C no.6
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• pp.459-464
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• 2010

Due to the application-specific nature of wireless sensor networks, the sensitivity to such a requirement as data reporting latency may vary depending on the type of applications, thus requiring application-specific algorithm and protocol design paradigms which help us to maximize energy conservation and thus the network lifetime. In this paper, we implement and evaluate a novel delay-adaptive sensor scheduling scheme for energy-saving data gathering which is based on a two phase clustering (TPC), in wireless sensor networks. The TPC is implemented on sensor Mote hardwares. With the help of TPC implemented, sensors selectively use direct links for control and forwarding time critical sensed data and relay links for data forwarding based on the user delay constraints given. Implementation study shows that TPC helps the sensors to increase a significant amount of energy while collecting sensed data from sensors in a real environment.