• 전력전자학회논문지
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• 제26권4호
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• pp.256-262
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• 2021

Six-phase motors can be used in industrial applications, such as an electric vehicle, due to their high reliability and low current magnitude per phase. An asymmetrical PMSM with two sets of three-phase windings is a commonly used structure for six-phase motors, with each winding set demonstrating a phase difference of 30°. Although the asymmetrical PMSM presents low torque ripples, its dynamic torque response deteriorates due to coupled components in the two three-phase windings. The decoupled VSD control is applied to eliminate the coupling effect. Load ratio control of two inverters for the six-phase PMSM is proposed in this study. DQ currents are controlled on the basis of two synchronous reference frames, and the six-phase drive system can be changed to a three-phase drive system when one inverter presents fault conditions. The operation and effectiveness of the proposed algorithm is verified through simulation and experiments. The six-phase drive system is transferred to a three-phase drive system by changing the current reference of the second DQ reference frame. Moreover, control of both torque and speed exhibits satisfactory performance before and after the mode change.

• 수면정신생리
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• 제7권2호
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• pp.115-119
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• 2000

목 적 : 십년 이상 각성장애를 보인 20세 남자환자를 분석하였다. 환자는 두통, 만성피로, 경한 주간졸리움증을 호소하였으나 조절할 수 없는 수면발작, 탈력발작, 입면시 환각이나 수면마비의 병력은 없었다. 방 법 : 야간 수면다원검사 (PSG), 반복적 수면잠복기 검사 (MSLT) 및 조직적합성 유전자검사 (HLA-typing)를 시행 하였다. 결 과 : PSG상 수면잠복기가 짧고 (4분), 렘수면잠복기도 감소하였고 (2.5분), 각성지표 (arousal index)가 시간당 15.7로 약간 증가되었으며, 수면 중 주기적 사지운동지표 (PLMS index)가 시간당 8.1로 관찰되었으나 운동과 연관된 각성지표 (movement arousal index)는 시간당 2.1로 높지 않았다. 잠효율은 (sleep efficiency)는 97.5%로 정상이었다. MSLT상 수면잠복기는 15분 21초로 정상이었으나 sleep-onset REM (SOREM)은 5회의 낮잠 시도 중 4회에서 관찰되었다. HLA-typing에서 DQ6-양성이었는데, 이는 기면증 환자에서 대개 관찰되는 유전자 위치인 DQB1*0602, DQA1*0102와는 다른 DQB1*0601 부위에 상응하였다. 결 론 : 일차성 각성장애의 원인이 되는 여러 질환 특히 일주기리듬장애나 기면증, 원발성 다면증과의 감별진단이 필요하며, 수면검사와 유전자검사 상 기면증의 새로운 변종일 가능성을 배제할 수 없다.

• 인간식물환경학회지
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• 제24권3호
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• pp.245-256
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• 2021

Background and objective: The vitalization of urban agriculture has increased various forms of experience-based education using school gardens, which raised the importance of school gardens in terms of value as well as the need to develop an implementation system for education-based agricultural experience service using school gardens. Thus, we reset the evaluation indicators from the previous study to establish objective evaluation indicators that enable quantitative comparison of school garden education services. Methods: Analytic hierarchy process (AHP) and direct question (DQ) surveys were conducted on 20 experts from October 12 to 19, 2020 after establishing the purpose and subjects of evaluation, and then the weights were calculated using the Expert Choice 2010 program. Results: First, we analyzed the problems of the previous indicators by categorizing the performance indicators and comparing and verifying them with six requirements of valuation. Then, we added 'welfare values' and established sub-indicators accordingly. The importance of value indicator in AHP was in the order of education values (0.544), health values (0.182), welfare values (0.164), environmental values (0.062), and economic values (0.049). The importance of environmental and economic values was relatively low, less than 0.1. The importance of sub-indicators was highest in cultivating character (0.144), followed by enhancing ecological sensitivity (0.141) > promoting mental health (0.134) > cultivating agricultural literacy (0.120) > improving social skills (0.104). And mitigating climate change in environmental values was lowest (0.009). Increase in income was the lowest (0.036). This can be regarded as the expression of change to increase the educational effect based on collective life and the connotative meaning of 'school'. In the case of DQ, the AHP weight and order were the same, but the environmental and economic values were relatively low, and the result was different from AHP weight. For sub-indicators, the importance in DQ was highest in promoting mental health (0.136), followed by promoting physical health (0.085), ]cultivating character (0.082), social integration (0.072), and enhancing ecological sensitivity (0.071). After reviewing related experts, we came up with 5 evaluation indicators and 16 sub-indicators for school garden education service, which are objective evaluation indicators that enable quantitative comparison. Conclusion: In the future, we will validate the socioeconomic values of school garden education services and contribute to revitalizing school gardens by establishing policy alternatives for effective operation and management of school gardens.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제34권4호
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• pp.258-267
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• 2023

Objectives: This study aimed to compare the utility of the Psychoeducational Profile-Revised (PEP-R), Korean Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (K-WPPSI-IV), and Vineland Adaptive Behavior Scale, Second Edition (VABS-II) for evaluating developmental disabilities (DD) in preschool children. Additionally, we examined the correlations between the PEP-R, K-WPPSI-IV, and VABS-II. Methods: A total of 164 children aged 37-84 months were assessed. Children's development was evaluated using the PEP-R, K-WPPSI-IV, VABS-II, Preschool Receptive-Expressive Language Scale, and Korean Childhood Autism Rating Scale, Second Edition. Results: Of the 164 children, 103 had typical development (TD) and 61 had DD. The mean of the PEP-R Developmental Quotient (DQ), K-WPPSI-IV Full-Scale Intelligence Quotient (FSIQ), and VABS-II Adaptive Behavior Composite (ABC) scores were significantly higher in the TD group than in the DD group (p<0.001). The estimated area under the curve of the PEP-R DQ, K-WPPSI-IV FSIQ, and VABS-II ABC scores was 0.953 (95% confidence interval [CI]=0.915-0.992), 0.955 (95% CI=0.914-0.996), and 0.961 (95% CI=0.932-0.991), respectively, which did not indicate a statistically significant difference. The PEP-R DQ scores were positively correlated with the K-WPPSI-IV FSIQ (r=0.90, p<0.001) and VABS-II ABC scores (r=0.84, p<0.001). A strong correlation was observed between the K-WPPSI-IV FSIQ and VABS-II ABC scores (r=0.89, p<0.001). Conclusion: This study found that the PEP-R, K-WPPSI-IV, and VABS-II effectively distinguished DD from TD in preschool children, and no significant differences in utility were observed between them.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.820-821
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• 2011

본 논문은 단상 line-start permanent- magnet (LSPM) 전동기가 가지는 비동기 운전영역에서 나타나는 다양한 토크성분을 해석적 방법으로 분석한다. 비 동기속도에서의 정상상태 전류를 DQ 등가회로를 이용하여 유도하였으며, 이를 이용하여 유도전류와 제동전류의 주파수를 확인하였다. 마지막으로 시간차분 해석을 이용하여 비동기 운전영역의 특정 속도에 대한 토크와 전류를 분석하였으며, 주파수 변환을 이용하여 각 전류의 주파수 성분을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.166-169
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• 2003

In this paper, a PWM Buck-Boost AC-AC converter for improvement of power quality of custom power is presented. The PWM Buck-Boost AC-AC converter is modelled by using circuit DQ transformation whereby the design guideline is obtained. Based on the analysis, the converter system is implemented with the design criteria and the experimental results show the validity of modelling and analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.262-265
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• 2000

This paper presents analysis of control characteristics of high power hybrid multilevel PWM rectifier without bulky and heavy isolation transformers. It will be shown that the DC voltages for multilevel output generation may be directly built up from AC utility source. The multilevel PWM rectifier is analyzed by using the circuit DQ transformation whereby the static and dynamic characteristics and some useful design equations are obtained. Finally to confirm the validity of the analysis MATLAB simulation are carried out.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.500-501
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• 2011

신재생 에너지를 계통과 효율적으로 연계하기 위해서는 일정한 DQ파형이 필요하다. 하지만 부하의 변동으로 전류가 작을 경우 노이즈의 영향으로 제어에 어려움을 겪게 된다. 따라서 본 논문에서는 효율적인 전류 제어를 하기 위해 DFT 기법을 사용하여 노이즈를 제거하고 기본파 전류 파형을 추출하여DQ 변환을 수행한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.442-443
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• 2011

In this paper, a voltage control method based on DQ transformation and Space Vector Pulse Width Modulation (SVPWM) for a single phase three-level converter is proposed. This control method is designed to use DC values instead of using instantaneous values of current which are usually used in single-phase application, so that it results in a fast and robust voltage control response. Simulation results demonstrate the validity of the control strategies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1003_1004
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• 2009

본 논문에서는, Matlab/Simulink를 사용하여 영구자석 동기전동기(PMSM)의 벡터제어 및 제어기설계에 대하여 기술하겠다. dq모델의 수학적 해석을 바탕으로 PMSM드라이브의 전류제어와 속도제어기에 Lag- controller를 사용하였다. Black block models과는 다른 시뮬레이션으로 모든 매개변수에 대해서 제어와 증명을 쉽게 할 수 있다. Matlab/Simulink로 로드 토크가 있는 PMSM을 증명하고 그 결과 값을 알아보았다.