• 한국농림기상학회지
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• 제4권4호
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• pp.197-202
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• 2002

A new method is used to estimate the amount of water evaporation from Class A Pan with higher precision and accuracy. The principle of method is to detect the weight change of a buoyant sinker resulting from a change in water level of Class A Pan. A strain-gauge load cell is used to measure the weight change. Field observation of evaporation was done at Pohang Meteorological Station from June 24 to August 4, 2002. By using this new method, it is possible to measure hourly evaporation accurately even under a strong solar radiation and wind disturbance, enabling a direct comparison of evaporation with other meteorological elements. At night, under low humidity and high wind speed conditions, more evaporation was recorded than during daytime. Maximum evaporation rates observed during this period exceed 1.0 mm/hour under the sunny and windy conditions with low humidity. To understand relationships between meteorological elements and latent heat flux at ground level, we suggest intensive held experiments using high accuracy evaporation recording instruments with hourly time interval.

• 한국대기환경학회지
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• 제9권3호
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• pp.207-215
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• 1993

In order to statistically predict $O_3$ levels in Seoul, the study used the TMS (telemeted air monitoring system) data from the Department of Environment, which have monitored at 20 sites in 1989 and 1990. Each data in each site was characterized by 6 major criteria pollutants ($SO_2, TSP, CO, NO_2, THC, and O_3$) and 2 meteorological parameters, such as wind speed and wind direction. To select proper variables and to determine each pollutant's behavior, univariate statistical analyses were extensively studied in the beginning, and then various applied statistical techniques like cluster analysis, regression analysis, and expert system have been intensively examined. For the initial study of high level $O_3$ prediction, the raw data set in each site was separated into 2 group based on 60 ppb $O_3$ level. A hierarchical cluster analysis was applied to classify the group based on 60 ppb $O_3$ into small calsses. Each class in each site has its own pattern. Next, multiple regression for each class was repeatedly applied to determine an $O_3$ prediction submodel and to determine outliers in each class based on a certain level of standardized redisual. Thus, a prediction submodel for each homogeneous class could be obtained. The study was extended to model $O_3$ prediction for both on-time basis and 1-hr after basis. Finally, an expect system was used to build a unified classification rule based on examples of the homogenous classes for all of sites. Thus, a concept of high level $O_3$ prediction model was developed for one of $O_3$ alert systems.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.400-403
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• 2007

This research describes how the class D amplifiers with power efficiency are designed and implemented for the PA audio systems. The configuration that makes use of the class D amplifier properties depends strongly on their applications. Thus in this paper the characteristics of the 2-level and 3-level PWM are analysed and the circuit implementation for them is presented. Using the proposed methods, they are designed and simulated for the further investigation. Test(Simulation) results present the improved performance that shows the satisfactory operations in controlling the PWM to the input signals.

• 대한수학교육학회지:학교수학
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• 제4권3호
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• pp.331-346
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• 2002

This study has two purposes. One is to know that it is Possible to use portfolio in the elementary math class. The other is to make a useful method for using portfolio. We got the following conclusion through the study. Portfolio gave students an opportunity that they could review their mathematical thinking. But it couldn't work very well for the low-level students. They didn't pay attention to the class. So, careful prepa-ration and training were necessary for the portfolio material. And the portfolio material must be prepared by appropriate contents. Teacher had to do math class by considering students ability. The math class could be much better for motivation, teaching-learning activity impro-vement and communication tool by using portfolio material. There are several imple-mentation processes in preparation, execution and utilization of the class. 1) Preparation: Teacher must decide if it is appropriate for portfolio by analyzing the course and textbook and set a final goal. And then teacher has to select an appropriate item and make a schedule for the class. The portfolio material must contain valuable things from which students learn mathematics and use in their life. The student level, utilization purpose and contents are considered when one prepares portfolio material. 2) Execution: Students are supposed to understand about the portfolio very well. It is important for them to get the opportunity for reviewing through math class diary, their opinion, friends opinion and teachers opinion. 3) Utilization: Parents review ameliorates the communication among teacher, student and parents about learning activity.

• 한국컴퓨터정보학회논문지
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• 제28권3호
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• pp.137-148
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• 2023

본 연구의 목적은 잠재프로파일분석(Latent Profile Analysis)을 적용하여 다문화청소년 어머니의 정신건강의 잠재유형을 분류하고 예측변인의 영향력을 분석한 후 잠재유형의 차이가 부모효능감에 어떠한 영향을 미치는가를 규명하기 위함이다. 이를 위해 다문화청소년 패널조사(MAPS) 9차년도(2019년) 패널데이터를 활용하였다. 분석결과, 첫째, 다문화청소년 어머니의 정신건강 유형은 '정신건강 중간 위험형'(class3) > '자아존중감 상위형'(class1) > '정신건강 고 위험형'(class4) > '문화적응과 일상생활 스트레스 상위형'(class2) 순으로 분석되었다. 둘째, '자아존중감 상위형'(class1) 집단과 비교해 다문화청소년 어머니의 가정경제 수준이 낮을수록, 다문화청소년 아버지(남편)의 학력이 중학교졸업 이하일수록, 한국어 수준이 낮을수록, 자녀와의 의사소통 정도가 낮을수록 '정신건강 중간 위험형'(class3) 집단에 속할 승산(Odds)은 높아지는 것으로 분석되었다. 셋째, '정신건강 중간 위험형'(class3) 집단과 '정신건강 고 위험형'(class4) 집단과 비교해 '자아존중감 상위형'(class1) 집단이 부모효능감에 유의미한 정(+)적인 영향을 미치는 것으로 확인되었다.

• 영어어문교육
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• 제12권4호
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• pp.211-234
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• 2006

The purpose of the present study was to investigate how two types of cooperative groupworks will affect learners' academic self-efficacy and English achievement in the first graders of Middle school. Experimental class A was done by similar-level groupwork, experimental class B by differential-level groupwork, and controlled class C by whole classwork. In order to accomplish the goals of the study, questionnaires on learners' academic self-efficacy were examined before and after the experiment. Also English achievement tests were done during the experiment. The analytic results of the questionnaires and English achievement tests were like the following conclusions: First, two types of cooperative groupworks were more effective on improving learners' academic self-efficacy than the whole classwork. Second, two types of cooperative groupworks were more effective on improving two levels' (higher and medium) academic self-efficacy. Third, among three types of classworks, differential-level groupwork was the most effective on improving learners' English achievement. Fourth, in case of medium-level learners, differential-level groupwork was more effective on improving their English achievement than similar-level groupwork.

• 한국학교수학회논문집
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• 제3권2호
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• pp.69-82
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• 2000

Mathematics is the subject that requires high mental function such as the ability of logically thinking and investigating. Because of the reason there exists much greater difference in students' individual scholastic abilities in mathematics class than in other classes. Recently many schools organize students into two or three level-based mathematics classes according to each student's level to solve the problem. But in spite of its many merits the new system of class organization has some problems. The problem which is pointed out as the most serious thing frequently is that many teachers still use the same textbook and the same teaching method for all students, not considering student's level. Obviously it causes the reduction of students' interest and motivation. In this point of view, I tried to solve such a problem by development and application of level learning materials reconstructed text book according to students' abilities and levels through this research. As the result of the research to examine the changes of students' emotional factors such as the recognition, interest, and attitude which influence on improving self-educability in learning mathematics has occurred, the following conclusion comes out. 1. Through the mathematics class utilizing level learning materials reconstructed textbook, students come to recognize that level learning materials are more effective than uniformed contents of the same textbook and get more active learning attitude. 2 The application of level learning materials in a level-based class has contributed to increasing students' interest in mathematics. Furthermore it was also effective in the positive changes of students' emotional factors such as the recognition, interest, and attitude which influence on improving self-educability in learning mathematics.

• 대한수학회보
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• 제58권3호
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• pp.593-602
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• 2021

We use a kind of modified Hurwitz class numbers to express the number of representing a positive integer by some ternary quadratic forms such as the sum of three squares, and the Fourier coefficients of weight 2 modular forms of prime level with trivial character.

• 충청수학회지
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• 제22권4호
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• pp.799-814
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• 2009

A class invariant is the value of a modular function that generates a ring class field of an imaginary quadratic number field such as the singular moduli of level 1. In this paper, using Shimura Reciprocity Law, we compute the Galois actions of some class invariants from the generalized Weber functions $\mathfrak{g}_0,\mathfrak{g}_1,\mathfrak{g}_2$ and $\mathfrak{g}_3$ over quadratic number fields with discriminant $D{\equiv}1$ (mod 12).

• 한국초등과학교육학회지:초등과학교육
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• 제35권1호
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• pp.39-53
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• 2016

This study aimed to understand students' learning in elementary science classes in terms of participatory perspective. Participatory perspective is based on the participationist views on learning. Based on the participatory perspective, this study used two concepts of participationism: 'the changes of learning on commognition' of Sfard (2007) and 'the identity' of Wenger (1998/2007). Based on these concepts, four episodes of an elementary science class were analyzed. The results showed that students carried out their learning from objective-level learning to meta-level learning. And students defined who they are by identifying and negotiating scientific meaning during the learning. These results showed students become members of science community through their participations in science class.