• 전기학회논문지
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• 제61권9호
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• pp.1232-1241
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• 2012

The ac side current of an high voltage direct current (HVDC) converter is characterized by highly non-sinusoidal waveform. If the harmonic current is allowed to flow in the connected ac system, it may cause unacceptable levels of distortion. Therefore, ac side filters are required as part of the total HVDC converter station, in order to reduce the harmonic distortion of the ac side current and voltage to acceptably low levels. The ac side filters are also employed to compensate network requested reactive power because HVDC converters also consume substantial reactive power. Among different types of filters, double-tuned filters have been widely utilized for HVDC system. This paper presents two design methods of double-tuned filter; equivalent method and parametric method. Using a parametric method, in particular the paper proposes a new design algorithm for a realistic system. Finally, the performance of the design algorithm is evaluated for a 80kV HVDC system in Jeju island with PSCAD/EMTDC program. The results cleary demonstrate the effectiveness of proposed design method in harmonics elimination and steady-state stability.

• 한국군사과학기술학회지
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• 제15권2호
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• pp.169-176
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• 2012

GPS(Global Positioning System) is widely used for the position estimation of an aerial vehicle. However, GPS may not be available due to hostile jamming or strategic reasons. A vision-based position estimation method can be effective if GPS does not work properly. In mountainous areas without any man-made landmark, a horizon is a good feature for estimating the position of an aerial vehicle. In this paper, we present a new method to estimate the position of the aerial vehicle equipped with a forward-looking infrared camera. It is assumed that INS(Inertial Navigation System) provides the attitudes of an aerial vehicle and a camera. The horizon extracted from an infrared image is compared with horizon models generated from DEM(Digital Elevation Map). Because of a narrow field of view of the camera, two images with a different camera view are utilized to estimate a position. The algorithm is tested using real infrared images acquired on the ground. The experimental results show that the method can be used for estimating the position of an aerial vehicle.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1251-1253
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• 2004

This paper is proposed a fuzzy neural network controller based on the vector controlled surface permanent magnet synchronous motor(SPMSM) drive system. The hybrid combination of neural network and fuzzy control will produce a powerful representation flexibility and numerical processing capability. Also, this paper is proposed speed control of SPMSM using neuro-fuzzy control(NFC) and estimation of speed using artificial neural network(ANN) Controller. The back propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The error between the desired state variable and the actual one is back-propagated to adjust the rotor speed, so that the actual state variable will coincide with the desired one. The back propagation mechanism is easy to derive and the estimated speed tracks precisely the actual motor speed. This paper is proposed the theoretical analysis as well as the simulation results to verify the effectiveness of the new method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.195-197
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• 2005

This paper is proposed adaptive fuzzy neural network(AFNN) and artificial neural network(ANN) based on the vector controlled induction motor drive system. The hybrid combination of fuzzy control and neural network will produce a powerful representation flexibility and numerical processing capability. Also, this paper is proposed control and estimation of speed of induction motor using fuzzy and neural network. The back propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The error between the desired state variable and the actual one is back-propagated to adjust the rotor speed. so that the actual state variable will coincide with the desired one. This paper is proposed the experimental results to verify the effectiveness of the new method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.655-656
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• 2005

In the future, plastic based system will play a crucial role in modem life, for examples, transparent display or disposable electronics and so on. In this paper, we introduced a new method to fabricate the metal line on the plastic substrate. Metal lines were fabricated by hot embossing and CMP process on PMMA (polymethylmethacrylate) substrates. A Si mold was made by wet etching process and a PMMA wafer was cut off from I mm thick PMMA sheet. A 100 nm thick Al was deposited on PMMA wafers. The Al deposited PMMA wafer and the Si mold carefully sandwiched which was directly imprinted by hot embossing. After imprinting process, a residual Al layer was removed by CMP process. Finally, we found the entire process may be very useful to fabricate the metal line on plastic substrates.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1456-1458
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• 2005

In this paper, a new approach for the synchronous reluctance motor control which ensures producing maximum torque per ampere(MIPA) over the entire field weakening region is presented. In addition, This paper presents a speed sensorless control scheme of SynRM using artificial neural network. Also, by adjusting the base speed for the field weakening operation according to the flux level, the current and voltage limit, the smooth and precise transition into the field weakening operation can be achieved. The proposed scheme is verified validity through simulation.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권6호
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• pp.24-29
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• 2014

To data, there was no systematic basis for establishing the content and allowed levels of general contamination substances in the Korean groundwater quality standards for non-drinking water. Recently, use of specific procedures for deriving valid groundwater quality standards have become mandatory. This study first investigated the methodology for deriving groundwater quality standards in the European Commission (EC), considering background groundwater quality and domestic and international standards related to water quality. Furthermore, this study investigated the existing specified procedure of standards related to water quality (e.g. surface water, drinking water, and wastewater). Our findings showed that EC and Member States presented the methods for deriving groundwater threshold values for general chemicals. Finally, we have proposed the following procedures of deriving Korean groundwater quality: (1) Selection of groundwater pollutant population, (2) selection and monitoring of priority substances, (3) monitoring, (4) selection of groundwater quality standard candidates, (5) selection of new substances and values for groundwater quality standards.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제37권3호
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• pp.467-482
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• 2023

본 논문에서는 인공지능 알고리즘에서 많이 사용되는 경사하강법(gradient descent method)을 대학수학 강좌에서 인공지능 활용사례로 사용할 수 있도록 연구한 교수·학습 기초자료를 소개한다. 특히 대학 미적분학 수준에서도 가르칠 수 있도록 자세한 개념 설명과 함께 복잡한 함수에 관해서도 쉽게 계산할 수 있도록 파이썬(Python) 기반의 SageMath 코드를 제공한다. 그리고 실제 인공지능 응용과 연계하여 선형회귀에서 발생하는 최소제곱문제를 경사하강법을 활용하여 풀이한 예시도 함께 소개한다. 본 연구는 대학 미적분학 뿐만 아니라 공학수학, 수치해석, 응용수학 등과 같은 고급 수학 과목을 지도하는 다양한 교수자들에게 도움이 될 수 있다.

• 한국식생활문화학회지
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• 제3권3호
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• pp.281-292
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• 1988

It is aimed to survey the housewive's interest and understanding on the Korean traditional dishes in relation to the importance and the significance of those dishes in the Korean traditional folk ceremony. Questionnaires were distributed to and answered by 667 housewives ranging from the the mother of kindergarden children to the mother of seniors in the university. Some of the significant findings and speculations derived from the analysis of data are summarized as follows: 1. About 90% of subjects have taken the knowledge on cooking the traditional dishes from their mothers and their grandmothers. And they have had many opportunities to known about traditional dishes through the home life education. 2. The kinds of the Korean traditional dishes which are used often at the folk ceremony are Tto k(Korean rice cake), Shikhae (fermented rice fruits punch), Sujong Kwa (persimmon fruits punch), Whachae(flower, fruits punch) etc. 3. About two thirds of the subjects have a little knowledge about Korean traditional special menu for the Korean folk ceremony, however, most of them observe New York's Day, Chusuk (The Korean Tranks giving Day), Dongji (The winter solstice), and Deborum (The 15th of the January on lunar Calender). 4. About 74% of the subjects use Korean traditional foods when they have Korean traditional folk ceremony. But there is a tendency to use nontraditional dishes among young housewives. 5. More than 73% of the housewives agree to the idea that Korean traditional dishes have to be succeeded and developed. 6. Most of the housewives think the Korean traditional folk ceremony is important and they are willing to make Korean traditional foods on the occasions, but they also think the ceremony must be rather simplified.

• Toxicological Research
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• 제13권3호
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• pp.281-291
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• 1997

The subacute toxicity of the combined vaccine (KGCC-95VI) for the prophylaxis against Japanese encephalitis and Hantaan virus infection, recently developed by Korea Green Cross Corporation, was investigated. KGCC-95VI was subcutaneously administered into the both sexes of New Zealand White rabbits at the dosage of 0, 10. 50 and 250 ml/kg body weight (20, 100 and 500 times the expected clincal dose) once a day for 30 days. There were no deaths and clinical findings during the experiment period. In both sexes. there were no statistically significant differences between the treated and control groups in urinalysis tests, hematological tests, blood chemistry tests and pathological examinations. The KGCC-95VI is considered not to have the subacute toxicity in the rabbits.