• 한국전자파학회논문지
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• 제20권9호
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• pp.967-973
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• 2009

본 논문에서는 두 개의 위상 동기 루프를 구성하여 이중으로 위상 고정시킨 band 위성통신용 국부 발진기를 설계하고 위상 잡음을 분석하였다. 설계된 위상 동기 발진기는 직렬귀환 유전체 공진발진기, 주파수 분주기, 위상검출기, 루프 필터 및 PLL-IC로 구성되어 있으며, 12.6 GHz의 발진 주파수를 2분주시켜 6.3 GHz에서 15.32 dBm의 출력값을 보였다. 제작한 발진기의 위상 잡음은 -81 dBc/Hz@100 Hz, -100.86 dBc/Hz@1 kHz, -111.12 dBc/Hz@10 kHz, -116 dBc/Hz@100 kHz 및 -140.49 dBc/Hz@1 MHz으로 매우 안정되며 우수한 특성을 보였다.

• 전자공학회논문지 IE
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• 제45권1호
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• pp.7-14
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• 2008

본 논문에서는 상용 TFT-LCD 빔 프로젝터를 이용하여 XGA급($1024{\times}768$) 초고해상 공간 광변조기(SLM)를 구현하고 광세기 및 위상변조 특성을 분석하였다. 즉, 상용 빔 프로젝터의 광학 모듈, 프로젝션 램프 및 팬들을 제거한 후 이를 효과적으로 보상할 수 있는 전자회로를 설계 제작 및 추가하여 관련 모듈제거 이전과 동일한 환경을 만들어 줌으로써 XGA급 초고해상 공간 광 변조기를 구현하였다. 구현된 초고해상 TFT-LCD 공간 광 변조기의 특성을 실험한 결과, 그레이 준위에 따른 선형적인 광 세기 및 위상변조 특성을 측정하였고 이를 분석한 결과 현재 상용화되어 있는 고가의 공간 광 변조기와 비교하여 높은 해상도와 위상변조 특성에 대한 우수한 선형성을 확인함으로서 저가의 고해상 공간 광 변조기의 구현은 물론, 이를 통한 광 정보처리 및 3D 디스플레이 시스템 또는 공간 주파수 필터 등의 입력 소자로서의 이용 가능성을 제시하였다.

• Journal of Power Electronics
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• 제3권2호
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• pp.99-114
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• 2003

This paper presents a feasible development on a highly accurate quick response adjustable speed drive implementation fur general purpose induction motor which operates on the basis of sensorless slip frequency type vector controlled sine-wave PWM inverter with an automatic tuning machine parameter estimation schemes. In the first place, the sensorless vector control theory on the three-phase voltage source-fed inverter induction motor drive system is developed in slip frequency based vector control principle. In particular, the essential procedure and considerations to measure and estimate the exact stator and rotor circuit parameters of general purpose induction motor are discussed under its operating conditions. The speed regulation characteristics of induction motor operated by the three-phase voltage-fed type current controlled PWM inverter using IGBT's is illustrated and evaluated fur machine parameter variations under the actual conditions of low frequency and high frequency operations for the load torque. In the second place, the variable speed induction motor drive system, employing sensorless vector control scheme which is based on three -phase high frequency carrier PWM inverter with automatic toning estimation schemes of the temperature -dependent and -independent machine circuit parameters, is practically implemented using DSP-based controller. Finally, the dynamic speed response performances for largely changed load torque disturbances as well as steady state speed vs. torque characteristics of this induction motor control implementation are illustrated and discussed from an experimental point of view.

• KIEAE Journal
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• 제16권5호
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• pp.73-79
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• 2016

Purpose: In order to improve the energy performance of existing buildings, so actively promoted green remodeling business. Also, improvement of the performance of envelope system of apartment housing is an absolute. The purpose of implementation of the data base and application plan of the envelope system for green remodeling of apartment housing. Method: For this study, It proposed a classification system of green remodeling envelope system constructed actual to select the applicable representative method and input material of apartment housing for green remodeling. In this study, divided into construction waste processing stage and production phase of the material for the boundary of the system, and implementation the classification system of the envelope system for applicable green remodeling. For this, established 6 environmental impact categories database. Result: As a result of various suggestions were available for case study research, alternative combinations of existing combinations than six kinds of environmental impact insulation system with superior input materials combining 96 kinds, window system, 12 kinds for determining the applicability of the established database. Depending on the account for a large proportion if compared to the detailed analysis of the environmental impact resulting from the production phase and disposal phase was analyzed that the operating management of the necessary input materials. Is considered that the economic performance and integrated energy performance required by the applicable public housing green remodeling evaluation techniques considered for future improvements insulation sheath.

• 수산해양교육연구
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• 제24권1호
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• pp.56-78
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• 2012

This study which is an alternative exploration for improving the quality level of instruction considering the perception of the teachers in early childhood education field on instructional design is to develop Differentiated Instructional Design Model coincides with the purpose of differentiated instruction curricula and with instructional design principles, and to find out whether the model has significant effect on development of teacher's professionalism. With these purposes, the perception of 343 teachers from early childhood education institutions are investigated, and after component variables are set by drawing the instructional design model available in early childhood education field and reviewing the literature of differentiated instruction model, the Differentiated Instructional design Model for Early Childhood are developed based on FGI(Focus Group Interview) expert evaluation. The experimental study of 88 teachers working in childcare facilities was implemented for effectiveness verification. As a result, first, most teachers consider the priority on making the lesson plans as the development of early childhood and Kindergarten Educational Subjects, and they realize the development of instructional design model which contributes on lesson planning and implementation is much needed. Second, the Differentiated Instructional design Model for Early Childhood are developed, which consists of the cyclic process - pre-lesson phase, lesson implementation phase, and assessment phase -based on development characteristics of early childhood. Third, the experiment of the developed model showed that the scores of experimental group is significantly higher than those of comparative group in knowledge and technique development aspect, and self-understanding development aspect among the aspects of development of teacher's professionalism.

• 한국간호교육학회지
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• 제4권1호
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• pp.66-80
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• 1998

With the opening of healthcare market, the health care environment in Korea is anticipating a drastic change. In this Internationally open market environment, it is necessary to introduce a systematic health care plan and DRG system which offer qualitative medical services as well as reduced cost. Purpose of this study is to develop and test the critical pathway for Cesarean section patient in the way to be possible the integrated inpatient management. It was adopted the process of six phases to develop the critical pathway as the theoretical framework implemented by Johns Hopkins Hospital, Maryland, U.S.A. In the first phase, make a selection of diagnosis/procedures to develop. In the second phase, organize a development team consisted of eight expertises working in maternity nursing area. In the third phase, analyze the overall medical service offered to patient through review medical records and decided the service content and the implementation period for the Cesarean section patient. In the forth phase, make out a preliminary critical pathway after verification of expert group on content validity. In the fifth phase, validity operate to ten Cesarean section patients to test implementation in practice by using the preliminary critical pathway, In the sixth phase, defined the final critical pathway. The result of this study was as follows. 1. There were classified 8 categories as monitoring/assesment, treatment, medication, activity, diet, test, consult, education/discharge plan for vertical axis and showed hospital stayed from admission to discharge for horizontal axis of critical pathway through analysis 68 Cesarean section patients medical records. 2. After critical review 68 medical records to make out a preliminary critical pathway, hospital stays for horizontal axis were showed 6 days, mean hospital stays were 7.5 days, 2.1 days were to be taken operation after admission and 4.2 days were stayed until discharge after operation. 3. After making out a questionare in 90 items of a medical service content of eight categories and verifying the content validity of expertises, the 85 items of the preliminary critical pathway were selected by expertises agreement over 88% and modified or deleted 5 items showing agreement below 75%. 4. After verifying a validity to 10 patients for 4 weeks, hospital stays were 5.9 days. There were deleted 1 item and modified or supplemented the 9 items of the 10 items.

• 상하수도학회지
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• 제33권6호
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• pp.421-428
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• 2019

This study developed an evaluation system of adaptation countermeasures for climate change in the water resources sector using the Analytic Hierarchy Process (AHP), and the assessment procedures were applied to the Second Chungcheongnam-do Climate Change Adaptation Implementation Plan (Chungnam Implementation Plan). Firstly, the evaluation criteria are composed of two levels according to the hierarchical structure, and AHP gives priority to 4 evaluation criteria of the first level and 16 alternative indicators of the second level. Secondly, after the importance of the evaluation criteria or indicators has been determined, the significance of each measure was evaluated by applying it to the water-sector measures of the Chungnam Implementation Plan, and the effectiveness of the evaluation system was validated. The Chungnam case study shows that the evaluation system will be more effective and efficient when it is applied during development phase rather than after the implementation plan is finalized. It is also expected that the evaluation system will be used to evaluate and prioritize climate change adaptation policies in other regions, and then to compare the means of adaptation to climate change in various regions and to select recommendation policies.

• 전력전자학회논문지
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• 제7권2호
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• pp.178-185
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• 2002

본 연구에서는 왜형되고 불평형인 전원의 정상분 순시전압 검출기법(Detection Method of Instantaneous Positive Sequence Voltage : PSD)에 의한 3상 3선 능동전력필터 시스템을 제작하였다. 불평형 및 왜형된 전원전압은 PSD에 의하여 정상분 순시전압을 실시간으로 검출한 후 순시전력이론의 상변환 행렬을 연산하고 있으며, 따라서 왜형되고 불평형된 전원조건에 순시전력이론을 적용하기 위하여 종전의 순시전력이론의 수학적인 구조를 변경할 필요가 없다. 본 연구에서 구현된 방법의 타당성을 입증하기 위해, 왜형된 B상 전압을 20% 증가시킨 전원과 불평형 비선형 부하 조건하에서 정상상태 및 과도상태의 실험을 수행하였으며, PSD가 없는 방법에 비하여 구현된 방법의 유용성을 입증할 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.75-82
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• 2015

This paper presents a new technique for enhancing power quality by reducing harmonics in the neutral conductor. Three-Phase Four-Wire (3P4W) system is commonly used where single and three phase loads are connected to Point of Common Coupling (PCC). Due to unbalance loads, the 3P4W distribution system becomes unbalance and current flows in the neutral conductor. If loads are non-linear, then the harmonic content of current will flow in neutral conductor. The neutral current that may flow towards transformer neutral point is compensated by using a series active filter. In order to reduce the harmonic content, the series active filter is connected in series with the neutral conductor by which neutral and phase current harmonics are reduced significantly. In this paper, solar PV based inverter circuit is proposed for compensating neutral current harmonics. The simulation is carried out in MATLAB/SIMULINK and also an experimental setup is developed to verify the effectiveness of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.955-959
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• 2003

A technique for realizing linear phase IIR filters has been proposed by Powell-Chau which gives a real-time implementation of H(z-1).H(z), where H(z) is a causal nonlinear phase IIR filter. Powell-Chau system is linear but not timeinvariant system. Therefore, that system has group delay response that exhibits a minor sinusoidal variation superimposed on a constant value. In the signal processing, this oscillation seriously degrade the signal quality. Unfortunately, that system has a large sample delay of 4L and also more computational complexity. Proposed system is present a reduced computational complexity technique by moved the numerator polynomial of H(1/z) out to cascade with causal filter H(z) and remain only all-pole of H(1/z), then applied truncated infinite impulse response to finite with truncated IIR filtel $H_L$(z) and L sample delay to subtract the output sequence from the top and bottom filter. Proposed system is linear time invariance and group delay response and total harmonic distortion are also improved.