• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권12호
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• pp.676-681
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• 2002

This paper presents the implementation and experimental investigation of sensorless speed control for a variable-speed PMSM(Permanent Magnet Synchronous Motor) in super-high speed compressor operation. The proposed control scheme consists of two different sensorless algorithms to guarantee the reliable starting operation in low speed region and full torque characteristics using the vector control in high speed region. An automatic switching technique between two control modes is proposed to minimize the speed and torque pulsation during the switching instant of control mode. A testing system of 3.3㎾ PMSM has been built and 90% load test results at 7000r/min are presented to examine the feasibility of proposed sensorless control scheme.

• 대한전기학회논문지:전력기술부문A
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• 제53권8호
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• pp.438-445
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• 2004

This paper presents a new numerical spectral domain algorithm devoted to blocking unsuccessful automatic reclosing onto permanent faults and fault distance calculation. Arc voltage amplitude and fault distance are calculated from the fundamental and third harmonics of the terminal voltages and currents phasors. From the calculated arc voltage amplitude it can be concluded if the fault is transient arcing fault or permanent arcless fault. If the fault is permanent automatic reclosure should be blocked. The algorithm can be applied for adaptive autoreclosure, distance protection, and fault location. The results of algorithm testing through computer simulation and real field record are given.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2219-2221
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• 2001

A communication protocol for automatic meter reading is designed for electronic power meter. Communicational functions and data structures are standardized and data reading software is developed according to the developed protocol. The communication protocol is designed with reference specifications, IEC 62056-31 and Distributed Network Protocol(DNP). For design, communicational functions and specifications of the industrial meters were analyzed for the purpose of developing a new one for KEPCO meters. The protocol is designed with 3 layer model, physical layers, data link layer and application layer. A documentation was completed with data gathering, data classification, authentication, error detection. An emulator system was made for testing the protocol. A meter reading software was developed using the protocol. Many different protocols and meter reading softwares are integrated into one with the developed protocol and software as KEPCO's standard.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.590-597
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• 1997

In this work, a new type of UV flame detection system was developed. In order to measure the performance of UV flame detector, various kinds of experiments was performed. The results show that the maximum response time of the UV flame detector is 0.2 seconds when the detection distance is one meter The advantages of this system include wide area, high speed response and high sensitivity. After testing the W flame detector in engine compartment it detected fire within 0.09 seconds and extinguished within 5 seconds. Hence, the UV flame detector can be applied in automatic fire suppression system for automobiles.

• 대한원격탐사학회지
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• 제9권2호
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• pp.35-49
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• 1993

GPS 위성은 측지위성으로 최근에 여러 분야의 민간용, 특히 자동차용 항법장치로 사용 되고 있다. GPS 위성으로 부터 얻어지는 위치정보와 디지탈 정보로 변환된 지도 정보를 결합하 여 자동차용 항법장치를 구성하였다. 이 논문에서는 이 시스템의 구현을 위한 서프트웨어의 작성 과 소프트웨어의 시험 예에 대하여 간단하게 요약한다.

• 비파괴검사학회지
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• 제24권3호
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• pp.275-281
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• 2004

대구경 배관에서 소구경 배관으로 연결하는 부위 및 배관의 방향 전환을 위해 사용하는 소켓용접부는 용입불량 및 사용시간이 경과되면서 내부로부터 진전될 수 있는 균열 등의 결함을 가질 수 있다. 그러나 지금까지 적용하고 있는 비파괴검사법인 액체침투탐상과 방사선투과검사로는 내부에 존재하는 균열성 결함의 검출이 어렵다. 본 연구에서는 소켓용접부 내부의 균열성 결함 검출을 위한 초음파 검사 기법을 확립하였고, 검사를 수행할 수 있는 초음파 탐촉자를 설계 제작하였으며, 자동으로 검사할 수 있는 검사 장비와 제어용 운영 프로그램을 개발하였다. 개발된 장비는 컴퓨터를 기반으로 하고 있으며, pulser/receiver를 내장하고 100 MHz 고속 A/D board를 사용하여 초음파 탐상기 역할을 프로그램으로 구현하였으며, ISA interface type으로 4축 제어용 motion controller를 개발하여 자동 검사를 수행하는 scanner를 제어하도록 하였으며, 검사 결과는 소켓용접부 단면을 실시간 영상으로 나타내도록 되어 있다. 인공결함 시험편의 결함을 평가한 결과 결함의 깊이가 1mm인 결함의 평가 길이는 실제 크기보다 작게 나타내고 있으며, 결함의 깊이가 증가할수록 결함의 길이가 더 크게 평가되었다. 본 연구로 개발한 장비는 원자력 발전소나 화학플랜트에 많이 널려 있는 소켓용접부 내의 용입불량, 피로 균열 등을 검출하여 객관적인 검사 결과를 제시할 수 있으므로 설비 안전 관리 및 보수 부위 결정에 기여할 수 있을 것으로 기대된다.

• 자동차안전학회지
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• 제4권2호
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• pp.32-36
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• 2012

The Automatic unmanned target object carrying system (AUTOCS) is developed for testing road vehicle radar and vision sensor. It is important for the target to reflect the realistic target characteristics when developing ASV or ADAS products. The AUTOCS is developed to move the pedestrian or motorcycle target for desired speed and position. The AUTOCS is designed that only payload target which is a manikin or a motorcycle is detected by the sensor not the AUTOCS itself. In order for the AUTOCS to have low exposure to radar, the AUTOCS is stealthy shaped to have low RCS(Radar Cross Section). For deceiving vision sensor, the AUTOCS has a specially designed pattern on outside skin which resembles the asphalt pattern. The AUTOCS has three driving modes which are remote control, path following and replay. The AUTOCS V.1 is tested to verify the radar detect characteristics, and the AUTOCS successfully demonstrated that it is not detected by a car radar. The result is presented in this paper.

• Journal of Biosystems Engineering
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• 제23권4호
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• pp.365-372
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• 1998

This study was carried out to develop a nutrient-solution mixing-and-supplying system, which used a low-cost metering device instead of expensive metering pumps and a fuzzy logic controller. A low cost and precise overflow-type metering device was developed and evaluated by testing the flow discharge for the automatic nutrient-solution mixing-and-supplying system for snail-scale hydroponic sewers. The fuzzy logic controllers, which could predict and meet the desired values of EC and supply rate of nutrient solution were developed and verified by simulation and experiment. this fuzzy logic controller, whose algorithm consists of four crisp inputs, two crisp outputs and nine rules, was developed to predict the desired value of EC and supply rate of nutrient solution and two crisp inputs, one crisp output and nine rules used to control EC to the desired values. The nutrient-solution mixing-and-supplying system showed satisfactory EC control performance with the maximum overshooting of 0.035 mS/cm and the maximum settling time of 15 minutes in case of increasing 0.7 mS/cm. also, the accuracy of the overflow-type metering device in terms of the full-scale error was 2.29% when using solenoid valve only and 0.2% when using solenoid valve and flow control valve together.

• 전기학회논문지
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• 제64권1호
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• pp.107-112
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• 2015

This paper introduces an evolutionary nonlinear regression based compensation technique for the short-range prediction of wind speed using AWS(Automatic Weather Station) data. Development of an efficient MOS(Model Output Statistics) is necessary to correct systematic errors of the model, but a linear regression based MOS is hard to manage an irregular nature of weather prediction. In order to solve the problem, a nonlinear and symbolic regression method using GP(Genetic Programming) is suggested for a development of MOS wind forecast guidance. Also FCM(Fuzzy C-Means) clustering is adopted to mitigate bias of wind speed data. The purpose of this study is to evaluate the accuracy of the estimation by a GP based nonlinear MOS for 3 days prediction of wind speed in South Korean regions. This method is then compared to the UM model and has shown superior results. Data for 2007-2009, 2011 is used for training, and 2012 is used for testing.

• 한국소음진동공학회논문집
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• 제20권12호
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• pp.1147-1152
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• 2010

The wet brakes used in an industrial forklift often produce noise on braking. Elimination or reduction of this squeal noise is an important task for the improvement of comforts. In this paper, a test rig was developed which was possible for testing of brake noise and an experimental measurement on squeal noise was performed. The causes of the brake noise are identified by experimenting how the factors such as automatic transmission fluid, the groove of friction-plate pad and the material of friction-plate pad affect the squeal noise. In order to identify the squeal characteristics, the signal analyses for noise are performed by using frequency spectrums. Experimental results showed that the viscosity of automatic transmission fluid and the groove pattern of friction-plate pad largely affect the reduction of the wet brake squeal noise in an industrial forklift.