• 대한수학교육학회지:수학교육학연구
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• 제13권1호
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• pp.25-55
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• 2003

In the school mathematics, the negative numbers have been instructed by means of intuitive models(concrete situation models, number line model, colour counter model), inductive-extrapolation approach, and the formal approach using the inverse operation relations. These instructions on the negative numbers have caused students to have the difficulty in understanding especially why the rules of signs hold. It is due to the fact that those models are complicated, inconsistent, and incomplete. So, students usually should memorize the sign rules. In this study we studied on the didactical phenomenology of the negative numbers as a foundational study for the improvement of teaching negative numbers. First, we analysed the formal nature of the negative numbers and the cognitive obstructions which have showed up in the historic-genetic process of them. Second, we investigated what the middle school students know about the negative numbers and their operations, which they have learned according to the current national curriculum. The results showed that the degree they understand the reasons why the sign rules hold was low Third, we instructed the middle school students about the negative number and its operations using the formal approach as Freudenthal suggest ed. And we investigated whether students understand the formal approach or not. And we analysed the validity of the new teaching method of the negative numbers. The results showed that students didn't understand the formal approach well. And finally we discussed the directions for improving the instruction of the negative numbers on the ground of these didactical phenomenological analysis.

• 환경영향평가
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• 제8권3호
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• pp.49-59
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• 1999

In this study, we individualize the clauses to sort out the troubled ones, draw up a interrelation model in order to visually organize the relations, and finally, suggest the desirable application idea. The interrelation model suggested in this study has been made based on the matrix method. On this matrix, we arranged the environmental factors on horizontal and vertical axis, and when we describe the relation of each factors, we set the horizontal axis as the base and divided the content into three grades : Fine, Medium, and Poor. In addition to that, we expressed those three grades into numerical value like 3 points for Level Fine, 2 points for Level Medium, and 1 point for Level Poor and then, we converted this numerical values into index numbers. We could classify the index numbers such as AS, PS, Q-index, P-index. AS is an index numerically shows the degree of giving environmental effect, PS is an index numerically shows the degree of receiving environmental effect, Q-index is an index shows the aggravate degree, and P-index shows the relation degree. The Q/P-index with large numbers has considerable effect on the environmental system, while the small numbered Q/P-index barely effect on the environmental system. Moreover, we classified the environmental factors into 5 levels(I~V) according to the relations between the Q-index and P-index. Level I is less affected by the environment and has more giving effect, while Level V is more sensitively affected by the environment and has more receiving effect, which we considered important. Therefore, we could come up with the result that if we consider the each level of factors when we evaluate the EIA, the result would be far more accurate and reliable since it contains mutual relation aspect of EIA. The suggested interrelation model in this thesis is presentable as one of those scoping system. We highly believe the need of scoping system in EIA and suggest the interrelation model as the alternative idea for scoping system.

• 대한수학회논문집
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• 제37권4호
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• pp.1259-1267
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• 2022

In this paper we present a full circle approximation method using parametric polynomial curves with algebraic coefficients which are curvature continuous at both endpoints. Our method yields the n-th degree parametric polynomial curves which have a total number of 2n contacts with the full circle at both endpoints and the midpoint. The parametric polynomial approximants have algebraic coefficients involving rational numbers and radicals for degree higher than four. We obtain the exact Hausdorff distances between the circle and the approximation curves.

• 지구물리와물리탐사
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• 제14권2호
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• pp.133-139
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• 2011

지구조석을 계산하는데 있어 가장 주요한 항은 달이나 태양에 의한 구면조화차수가 2인 항으로서 지구조석의 약 98%를 이루며, 나머지는 3차 이상의 고차 항들이다. 그런데 차수 3항과 그 이상의 고차수의 항들의 값들은 차수 2항과는 다른 상수가 각각 곱하여져서 계산되어야 한다. 본 연구에서는 조석에 의한 중력변화, 변위 및 수직선의 변화에 대한 바른 계산을 검토하였으며, 필요한 관련상수들을 다시 구하였다. 동일차수내의 다른 계수의 조화함수적 조석주기의존성을 토의하였다. 한편, 지구조석을 계산하는데 관련된 중요한 개념들을 요약 소개하였다.

• Geomechanics and Engineering
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• 제14권2호
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• pp.187-193
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• 2018

Water inrush through the destruction of water resisting rock mass structure was divided into direct water inrush, key block water inrush and splitting water inrush. In the direct water inrush, the Reynolds numbers has a significant effect on the distribution of the water flow and vortex occurred in the large Reynolds numbers. The permeability coefficient of the fracture is much larger than the rock, and the difference is between 104 and 107 times. The traditional theory and methods are not considering the effect of inertia force. In the position of the cross fracture, the distribution of water flow can only be linearly distributed according to the fracture opening degree. With the increase of Reynolds number, the relationship between water flow distribution and fracture opening is studied by Semtex.

• 대한수학회논문집
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• 제38권4호
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• pp.1127-1139
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• 2023

We investigate an extension of Schauder's theorem by studying the relationship between various s-numbers of an operator T and its adjoint T^*. We have three main results. First, we present a new proof that the approximation number of T and T^* are equal for compact operators. Second, for non-compact, bounded linear operators from X to Y, we obtain a relationship between certain s-numbers of T and T^* under natural conditions on X and Y . Lastly, for non-compact operators that are compact with respect to certain approximation schemes, we prove results for comparing the degree of compactness of T with that of its adjoint T^*.

• 대한수학회지
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• 제45권3호
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• pp.835-840
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• 2008

The main result of this paper shows that every reciprocal Littlewood polynomial, one with {-1, 1} coefficients, of odd degree at least 7 has at least five unimodular roots, and every reciprocal Little-wood polynomial of even degree at least 14 has at least four unimodular roots, thus improving the result of Mukunda. We also give a sketch of alternative proof of the well-known theorem characterizing Pisot numbers whose minimal polynomials are in $$A_N=\{[{X^d+ \sum\limits^{d-1}_{k=0} a_k\;X^k{\in} \mathbb{Z}[X]\;:\;a_k={\pm}N,\;0{\leqslant}k{\leqslant}d-1}\}$$ for positive integer $N{\geqslant}2$.

• Child Health Nursing Research
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• 제2권1호
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• pp.69-92
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• 1996

The purpose of study was : 1) to analyze the trend of research on the family with chronically ill children in Korea, 2) to suggest direction for future study on the family with chronically ill children, and contributing to the use of intervention in family nursing practice. Research studies on the family with chronically ill children were selected from the Korean Nusre, the Korean Nurses' Academic Society Journal, and from dissertations, which were conducted between 1975 and 1995. The total numbers of the studies were 35. These studies were analyzed for 1)time of publication or presentation, 2)research design, 3)characteristics of subjects, 4) type of chronic disease, 5)main concepts, 6)measurement tool, 7) the sis for a degree or nondegree, 8) result of correlational studies. The findings of the analysis were as follows : 1) The numbers of studies on the family with chronically ill children have increas rapidly the early 1990's. In research design, the numbers of survey research studies were the highest. Especially, the most frequently research design was the correlational survey. There were 19 correlational studies(25.7%) during the early 1990's. 2) The subjects in 16 studies(45.7%) were mother of chronically ill children and, in 8 studies (22.9% ) were their parents. 3) In most types of chronic diseases, there were 14 hematooncologic disease(32.6%) and 14 hadicapped children (32.6% ). 4) Frequently used research concepts were stress, degree of coping or way of coping, social support, parents' support, family functioning, intensity of family and family adaptation. 5) Acceding to the results of correlational studies, the more family stress was higher the more degree of coping, family functioning, intensity of family and degree of family adaption was lower. The more degree of social support was higher the more stress was lower and degree of coping, family functioning and intensity of family was higher. The more family functioning was higher the more intensity of family and family adaptation was higher. 6) 24 researches on the family with chronically ill children were done for a thesis for a degree and 11 were nondegree research studies. The following suggestions are made based on the above findings : 1) The pattern of these studies related to the family with chronically ill children in domain of Nursing need to be compared with trend in other domains. 2) More replicated research on the family with chronically ill children is needed to develop family nursing intervention and prove the effect of that and more qualitative research on the family with chronically ill children is needed to comprehensive indepth the family with chronically ill children. 3) Further research on the family with chronically ill children is needed to verify subjects and type of chronic disease, develop applicable measurement tools in Korea and identify relation between other concepts. 4) Family nursing researchers should make an effort to apply research result in various clinical settings and community settings, and try to carry out not only team research with clinical nurse but also other multidisciplinary researcher related to the family.

• 기본간호학회지
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• 제6권2호
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• pp.331-346
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• 1999

Many studies have reported that a lot of nursing colleges do not have good facilities for the nursing practice in hospitals, so many students do not have the good ability which is needed to be a competent nurse. The purpose of this study was to develop a program in which students could improve their ability in fundamental nursing skills before the graduation. This study was primarily designed to identify items of the fundamental nursing practice in which nursing college students have perceived deficiencies. According to previous studies, a total 75 items were presented. In Identifying them, a modified Porter format was used. The questionnaire contained three sections. A. How well do you think you can/could perform the item when you graduate/graduated the college? B. How well do you think you should perform/should be able to perform the item when you graduate/graduated the college? C. How important do you think the item is? For each of the 75 items, the respondents were instructed to answer the above three questions, by circling a number on a rating scale extending from 1 to 5, where low numbers represented a low degree of performance or minimum amount, and high numbers represented a high degree of performance or maximum amount. The perceived degree of deficiency in performance on each questionnaire item was obtained by subtracting the answer to Part A of an item from that to of Part B. The larger difference means a larger perceived degree of deficiency in performance. This method of measuring the perceived degree of deficiency in performance is an indirect measure derived from two direct answers by the respondent for each item. From this result Part C of each item was used to rank the items, and the items were prioritized. The items which had the highest priority were IV injection, simple catheterization, indwelling catheterization, CPR, and nurse recording. By this method, through these results from a nursing college, and the items which will be used first in developing the supplementation program for nursing college students can be identified.

• 동아시아식생활학회지
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• 제15권2호
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• pp.226-234
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• 2005

A study was conducted to improve satisfaction to school food service and to furnish source materials for nutrient education by researching degree of satisfaction of middle school students to school food service. Following results are from the study that targeted 215 male students and 173 female students in 5 middle schools in Daegu. Satisfaction rates regarding taste of foods, smell, proper temperature, use of seasonal food, cafeteria atmosphere, numbers of side dishes, and kindness of the cook in a cafeteria were higher than dissatisfaction. And dissatisfaction rates were higher in quantity and quality of foods, sanitation, purity of table wares, opening to nutrient education and related informations for students, opinion reflection of students, food serving time and gratification to food serving than the opposite. But the degree of general satisfaction on school food service were higher than the degree of general dissatisfaction. Sanitation was the first thing to be changed in school food service, then quantity of food and taste for the last. And there were notable differences between male students and female students in sanitation satisfaction. The variables that influence on satisfaction to school food service were sanitary administration, numbers of side dishes, quantity of foods, nutrient, smell and taste when ranked. And the main three things that have similar rate in quantity with satisfaction rate are taste, smell and nutrient of school food service. Through these followed results, degree of general satisfactions to school food service were higher than degree of general dissatisfactions. But sanitation, quantity and quality of foods, taste, and food serving size were not satisfactory for students in rate. Therefore it has to be improved to enhance satisfactions to middle school food service.