• 전기학회논문지
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• 제58권8호
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• pp.1457-1462
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• 2009

This paper proposes a compensating algorithm for the secondary voltage of a coupling capacitor voltage transformer (CCVT) in the time domain by considering the hysteresis characteristics of the core. The proposed algorithm estimates the three error terms i.e. the voltage across the secondary winding parameters, the voltage across the primary winding parameters, and the voltage across the capacitor and the tuning reactor. These three terms are added to the measured secondary voltage to obtain the correct voltage. The algorithm reduces the errors of the CCVT significantly both in the steady state and during a fault. The performance of the algorithm is verified under the various fault conditions by varying the fault distance, the fault inception angle, and the fault impedance with the EMTP generated data. Test results clearly indicate that the algorithm can increase the accuracy of a CCVT significantly under the fault conditions as well as in the steady state. The algorithm helps improve the performance of a protection relay or a metering device.

• 한국생활과학회지
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• 제5권1호
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• pp.89-98
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• 1996

The objectives of this study were (1) to determine the rank of purposes of Korean secondary school home economics education related to three systems of action: technical, communicative, and emancipatory action by home economics(HE) teachers and HE teacher educators, (2) to compare differences between HE teachers and HE teacher educators concerning the degree of importance and achievement of the purposes of current Korean secondary school HE education. Respondents in this study were 225 HE teachers and 35 HE teacher educators. The survey method was used in this descriptive study. To determine the rank, Borich's needs assessment model was used. The data were analyzed by using t-test to compare the differences between the two groups. To promote a good life and the full development of human beings, to develop creative and critical thinking, to make morally defensible judgments, and to develop self-esteem were needed purposes for Korean secondary school HE education. Overall, the most high ranked purpose needs for both groups related to emancipatory action. The two groups were significantly different on the degree of the importance of evaluating family and social conditions, acquiring the skills needed as a wage earner and a homemaker, developing creative and critical thinking, and demonstrating proficiency of homemaking work. The teachers and teacher educator groups were significantly different on the degree of the achievement of making morally defensible judgments, understanding Korean traditional culture, and taking care of each other.

• Journal of Korean Biological Nursing Science
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• 제18권2호
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• pp.69-77
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• 2016

Purpose: This study aimed to investigate the effects of a secondary stroke prevention education program on the health risk indicators and self-care compliance of stroke patients. Methods: A non-equivalent control group pretest-posttest design was used to select the participants. Subjects were 54 stroke patients (27 in the experimental group and 27 in the control group) hospitalized in a K university hospital in D city, Korea. Health risk indicators and self-care compliance were measured both for a baseline, as well as after intervention. The data was analyzed using a chi-square test, paired t-test and ANCOVA. Results: There were significant differences in systolic blood pressure, diastolic blood pressure, fasting blood sugar, weight and self-care compliance. Conclusion: The results of the study indicate that an educational secondary stroke prevention program is effective for health risk indicators and self-care compliance of patients. Therefore it can be used as an effective nursing intervention in clinical practice.

• 한국과학교육학회지
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• 제20권2호
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• pp.244-249
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• 2000

본 연구에서는 현직 중등학교의 과학교사들을 대상으로 그들의 과학관과 학습관을 조사하였고 이 둘이 어느 정도 관련되어 있는가를 알아 보았다. 교사들은 1정 자격연수에 참여한 83명의 교사들이었는데, 평균 연령 28.7세, 평균 경력 4.0년이었으며, 근무하고 있는 지역과 학교가 다양하였다. 사용한 설문지는 권성기와 박승재(1995)가 사용하였던 '과학의 본성에 대한 인식조사지'와 '구성주의 학습관 조사지'였다. 이 조사지들은 11등급 척도로 -5에서 5까지 표시하게 되어 있었는데, 자료의 분석은 t 검증과 ANOVA를 사용하였다. 자료들을 분석한 결과 중등 과학교사들은 상대주의, 연역주의, 도구주의, 과정주의적인 과학관과 구성주의적인 학습관을 나타내었다. 그리고 그들의 과학관과 학습관 간에는 높은 관련성이 있었다.

• Nuclear Engineering and Technology
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• 제23권3호
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• pp.275-284
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• 1991

핵연료봉의 정방형 또는 삼각형 배열내의 2차 난류 유동의 해석은 연료봉내의 온도분포와 열전달 과정의 해석에 있어서 중요한 문제이다. 비등방성 난류모델과 등방성 난류모델을 사용하여 속 도장을 구하였고 열수력학적 성질이 일정하다는 가정하에 지배방정식을 유한 요소법을 사용하여 수치해석적인 방법으로 해를 구하였다. 또한 연료봉 표면 근처에서는 유체의 유동이 난류가 아니기 때문에 축 방향 속도는 벽의 법칙에 의해서 계산하였다. 이러한 방법에 의해서 구해진 해는 실험 결과와 비교되었고 비교적 잘 일치하였다.

• 대한가정학회지
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• 제31권3호
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• pp.47-62
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• 1993

The purpose of the study were to: (1) determine important home management concepts in the secondary home economics education curriculum, (2) identify the educational needs related to home management perceived by students, home economics teachers, and university professors, (3) identify the factor structure of the home management concepts, (4) use the findings to make recommendations for defining the area of home management in the secondary home economics curriculum. Three versions of the questionnaire were used to assess the needs. One questionnaire was for students, one for home economics teachers, and one for professors. A total of 1,029 students, 385 home economics teachers, and 45 professors responded to the questionnaires. the data were analyzed by using the descriptive statistics, one way ANOVA with scheff -test, and factor analysis. Forty home management concepts were selected based on the related literatures. The respondants perceived these important for the secondary home economics curriculum. However, 36 home management concepts had differences in perceived importance among students, teachers, and professors. Nine factors emerged from the factor analysis. The three factors that were judged of most importance by students were communication and stress management, making money and helping household tasks, and leisure time activities. The professors and teachers perceived decision making and management process and knowing and utilizing resources most important.

• 한국환경교육학회지:환경교육
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• 제2권1호
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• pp.5-33
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• 1991

The purpose of the study was to investigate attitudes toward to, values and expectations of environmental education of Korean students and teachers and to provide basic data and reference materials needed to development of environmental education curricula for primary and secondary schools. A review of the related literature, a series of conferences with teachers and specialists in environmental education and environmental sciences. and questionnaire survey were methods employed in this study. Survey question were developed to explore attitude and responses of primary and secondary school students and teachers on various types of issues and problems of environmental education at personal level as well as on their future prospects attitudes values and expectations with which had been dealt in this study were categorized into personal feeling on environmental issues and problems at both national and regional levels issues and problems of current environmental education pre service and in service training of teachers for environmental education instruction and so on. The sample population for the survey was selected by using the stratified cluster and random sampling techniques with respect to regional area, school level, sex and grade, The subjects used in this study were 1,633 students and 385 teachers of primary and secondary schools across the country. The results of the survey were summed up and recommendations to be considered in the revision of sixth national curricula for primary and secondary schools were also suggested.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 춘계 학술대회논문집
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• pp.155-161
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• 1999

The three-dimensional turbulent cascade flows with and without endwall fences are numerically investigated by solving the incompressible Navier-Stokes equations with a high-Reynolds number $k-{\varepsilon}$ turbulence closure model. A projection method based algorithm is used in the finite-volume formulation, with the second order upwind-differencing scheme for the convective terms. First, assessments on accuracy of the present method are made by comparing the static pressure distributions at the mid-span of the cascade with measured data, and also by confirming the experimental observations on the choice of an optimal fence height for the secondary flow control. In understanding the three-dimensional nature of the secondary flow in turbine cascade, the limiting streamline patterns and the static pressure contours at the suction surface of the blade as well as on the cascade endwall are employed to visualize the effectiveness of the endwall fence for the secondary flow control. Analysis on the streamwise vorticity contour maps along the cascade with the three-dimensional representation of their iso-surfaces reveals the strucuture of the complicated vortical flow in the turbine cascade with endwall fence, and also leads to an understanding on formation of the counter-rotating streamwise vortex over the endwall fence, in explaining the mechanisms of controlling the secondary flow and also for the proper selection of an optimal fence height.

• 한국전산유체공학회지
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• 제14권2호
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• pp.9-18
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• 2009

The cargo containment system (CCS) for ships carrying cryogenic fluid consists of at least two levels of barriers and insulation layers. It is because, even though there is a small amount of leak through the primary barrier, the liquid tight secondary barrier blocks further leakage of the cryogenic fluid. However, once the secondary barrier is damaged, it is highly possible that the leaked cryogenic fluid flows through the flat joint made of glass wool and reaches the inner hull of the ship. The primary objective of the present study is to investigate the influence of the damage extent in the secondary barrier on the amount of leaked cryogenic fluid reaching the inner hull and the temperature distribution there. Simulation results using a computational fluid dynamics tool were compared with the experimental data for the leaked cryogenic fluid flow and evaporation in the secondary insulation layer. The experimental and computational results suggest that, unless there is a massive leak, the cryogenic fluid mostly evaporates in the insulation layer and does not reach the inner hull in the state of liquid.

• 설비공학논문집
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• 제27권7호
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• pp.344-353
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• 2015

In the present study the characteristics of turbulent oscillatory flows in a square-sectional $180^{\circ}$curved duct were investigated experimentally. A series of experiments for air flow were conducted to measure axial velocity profiles, secondary flow velocity profiles and pressure distributions. The measurements were made by a Laser Doppler Velocimeter (LDV) system with a data acquisition and processing system which includes Rotating Machinery Resolve (RMR) and PHASE software. The results from the experiment are summarized as follows. (1) The maximum velocity moved toward the outer wall from the region of a bend angle of $30^{\circ}$. The velocity distribution had a positive value extended over the total phase in the region of a bend angle of $150^{\circ}$. (2) Secondary flows were generally proportional to the velocity of the main flow. The intensity of the secondary flow was about 25% as much as that in the axial direction. (3) Pressure distributions were effects of the oscillatory Dean number and respective region.