• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.7-12
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• 2013

In this paper, we propose a brushless DC motor drive system for active knee prosthesis and low-cost estimation method for phase current from DC-link current. To control motor torque directly, current sensing is very important and current sensing point should be synchronized with voltage switching command to minimize the effect of switching noise in current measurement, For maintaining small form factor, simplifying control schemes and achieving low-cost system, control schemes using DC-link current are used. Moreover, we incorporated phase current estimation method using analog MUX for minimizing current estimation error between DC-link current and phase current. The validity of the proposed system is verified through experimental works.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.759-762
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• 2014

반도체소자의 제조 공정 기술 중 구리패턴을 얻기 위해서 사용하는 화학.기계적 연마(CMP)를 이용한 평탄화와 연마 공정에서 Wafer에 도포된 구리의 두께를 실시간으로 측정하여 정밀하게 제어할 필요가 있는데, 이때 획득되는 센서값을 실제 두께 값으로 환산하는 계산과정에서 오차가 발생할 수 있다. 실제 측정 값에 근사한 값을 얻도록 단순평균을 이용한 방법, 이동 평균, 필터 들을 사용하여 결과를 비교하여 옹고스트롬 단위의 두께를 실시간으로 측정하는 제어 시스템의 편차를 줄이도록 하는 방법의 구현에 대해 기술한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.729-732
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• 2009

본 논문에서 제안하는 시스템은 사용자가 단순히 버튼 만 클릭하면 자동으로 축사의 배설물을 청소하며 작업을 마무리 하게 된다. 만약 온도가 상승하여 위험한 경우가 발생시에는 열 감지 센서가 작동하여 환풍기를 돌리고, 또한 지붕에 물을 분사시켜서 온도를 낮추어 폐사하는 것을 막을 수 있다. 이 시스템은 소수의 인력으로 다양한 크기의 축사를 관리 감독 할 수 있는 특징을 갖는다. 본 연구의 기술은 LabVIEW 소프트웨어 기술과 온도센서 및 전자소자인 스위치를 이용하여 모니터링시스템과 인터페이스 하는 기술이다. 축사의 축소화된 모델을 제작하여 직접 구현하여 문제점들을 보완하는데 주안점을 두었다. 또한 CCD 카메라를 설치하여 원격지에서 직접 축사 현장을 감시하면서 작업을 할 수 있도록 화상 모니터링시스템도 구축하였다.

• Convergence Security Journal
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• v.18 no.3
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• pp.77-85
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• 2018

With the convergence of communications network between control system and public network, such threats like information leakage/falsification could be fully shown in control system through diverse routes. Due to the recent diversification of security issues and violation cases of new attack techniques, the security system based on the information database that simply blocks and identifies, is not good enough to cope with the new types of threat. The current control system operates its security system focusing on the outside threats to the inside, and it is insufficient to detect the security threats by insiders with　the authority of security access. Thus, this study conducted the importance analysis based on the main event log list of "Spotting the Adversary with Windows Event Log Monitoring" announced by NSA. In the results, the matter of importance of event log for the detection of insider threats to control system was understood, and the results of this study could be contributing to researches in this area.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.846-847
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• 2016

LED lighting is energy in lighting control based on had developed into a human-centered / multi-functional lighting systems from simple one trillion people thereby using environmental change by combining IT technology and software, including a variety of sensor functions and communication functions, depending on the evolution of the IT Convergence Era the reduction, and the strength and the color tone customized illumination of the user-section of light has been desired. For this intelligent lighting system is applied to the sensor and the control center of the user should be possible, and it is necessary for this artist platform of the communication module. In this paper, we propose a communication platform that utilizes Bluetooth BLE module for LED lighting control.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.2
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• pp.70-78
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• 1997

Proportional-integral-derivative(P1D) controllers have been still widely used in industrial processes due to their simplicity, effectiveness, robustness for a wide range of operating conditions, and the familiarity of control engineers. And a number of recent papers in fuzzy systems are showing that fuzzy systems are universal approximators. That is, fuzzy controllers are capable of approximating any real continuous function on a compact set of arbitrary accuracy. In this paper, we derive the linear PID control law from the fuzzy control algorithm where all fuzzy sets for representing plant state variables and a control variable use common triangular types. We first lead a linear PD control law from a fuzzy logic control with only two fuzzy sets for error and change-of-error. And then we derive the linear PID control law from a fuzzy controller. We here assumed that the intervals of error, change-of-error, and integral error could be partitioned into arbitrary numbers, respectively. As a result, a linear PID controller is only a sort of various fuzzy logic controls.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.118-124
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• 2017

An air cooling, open cathode type polymer electrolyte membrane fuel cell (PEMFC) has the advantages of system simplification and cost effectiveness. Open cathode PEMFC could suffer from reduced performance due to the membrane dehydration in low humidity of air. Effects of the cathode air flow rate, anode purge interval and long term storage on PEMFC performance were investigated in this work. Fan voltage is an important factor on air cooling PEMFC performance because the cathode air flow rate and stack temperature were controlled by fan voltage. The dead ended anode (DEA) method was applied to increase hydrogen usage. Periodical purge was used to discharge accumulated water and gas. The influence of long term non-operating condition on PEMFC performance degradation due to the membrane dehydration was also studied and the quick recovery method was developed.

• Convergence Security Journal
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• v.17 no.5
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• pp.35-40
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• 2017

The control system can have such threats as information leakage and falsification through various routes due to communications network fusion with public network. As the issues about security and the infringe cases by new attack methods are diversified recently, with the security system that makes information data database by simply blocking and checking it is difficult to cope with new types of threats. It is also difficult to respond security threats by insiders who have security access authority with the existing security equipment. To respond the threats by insiders, it is necessary to collect and analyze Event Log occurring in the internal system realtime. Therefore, this study could find out whether there is correlation of the elements among Event Logs through correlation analysis based on Event Logs that occur real time in the control system, and based on the analysis result, the study is expected to contribute to studies in this field.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.211-212
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• 2010

DC 배전망에서 전기자동차 급속 충전 시스템은 대용량 전력 변환기를 통해 AC 배전망의 전압을 DC 전압으로 변환하여 DC 입력형 급속 충전기에 배전한다. DC 입력형 급속 충전기는 인버터기능이 제거됨으로 구조를 단순화하고 소형경량화 할 수 있다. 또한 충전소 내에 설치된 다수의 충전기 각각이 수행하던 전류 고조파 저감, 역률 향상, 양방향 전력 제어와 같은 기능들을 하나의 장치가 일괄 수행함으로서 충전소 인프라 단위의 신뢰성을 높일 수 있다. 본 논문은 DC 배전망에서의 전기 자동차 급속 충전 시스템의 특징에 대해서 설명하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.367-372
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• 2017

LED illumination has been developed from simple illumination to human oriented multi-functional system depending on the IT convergence trends. Thus, the convergence of IT technology such as various types of sensor and communication functions with application software can make saving of energy, and there are also several needs about the tailor-made illuminations requirements for the diverse users who want to take their own colors, strengths of the light. For the adaption of these kinds of intelligent system illumination, user oriented sensor and control should be possible. The LED lighting control system transmits and receives data via the Bluetooth mesh network and provides functions such as LED lighting control, LED lighting condition monitoring, energy usage monitoring, and energy peak point management. Therefore, in this paper, we suggest wireless communication platform and control system for the LED illumination control. We can expect life extension of LED illumination, and energy saving through this suggested system.