• Journal of Internet Computing and Services
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• v.19 no.5
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• pp.107-113
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• 2018

Object-oriented databases (OODBs) canbe used for many non-traditional database application areas such as computer-aided design, etc. Usually those application areas require advanced modeling power for expressing complicated relationships among data sets. OODBs have more distinguished features than the traditional relational database systems. One of the distinguished characteristics of OODBs is class hierarchy (also called inheritance hierarchy). A class hierarchy in an OODB means that a class can hand down the definitions of the class to the subclass of the class. In other words, a class is allowed to inherit the definitions of the class from the superclass. In this paper, we present performance evaluation metrics for class hierarchy in OODBs from a concurrency control perspective. The proposed performance metrics are developed to determine which concurrency control scheme in OODBs can be used for a given class hierarchy. In this study, in order to develop performance metrics, we use class hierarchy structure (both of single inheritance and multiple inheritance), and data access frequency for each class. The proposed performance metrics will be also used to compare performance evaluation for various concurrency control techniques.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1882-1893
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• 2016

This study intended to look into the causal relations, in which a ski class conducted at a college is linked from college students' participation motivation to satisfaction and revisit. Among others, this study intended to boost the quality of the ski class conducted at a college with focus on the difference between the influences on satisfaction and revisit according to pre/post class participation. Further, the purpose of this study is to inquire into an ultimate basic plan required for winter sports development on the basis of the deduced results, through which this study drew the conclusion as follows: First, it was found that the influence relationship between class satisfaction before/after class was established in a joy seeking factor according to ski class participation motivation. Second, the daily routine deviation factor among the sub-factors of ski class participation motivation was found to have a positive effect on revisit before/after class while friendship promotion factor, health factor and physical strength factor were found to have an influence on revisit after class.

• Journal of the Korean Society of Earth Science Education
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• v.10 no.2
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• pp.199-213
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• 2017

The purpose of this study was to find out what pre-service teachers' views of as a good science class in evaluating class demonstrations. The study was conducted on 32 students in the second year of college who are attending teacher training schools located in central region, Korea. 32 pre-service teachers demonstrated the class with a group of 2 students, and a total of 16 lessons were demonstrated. They also evaluated the class by participating in 15 lessons except ones own class. Therefore all the collected evaluation papers were 480 sheets. This study analyze this evaluation paper and find out the good science class that earth science pre-service teachers think. As a result, the pre-service teachers' views of good science class analyzed by 3 categories. The three categories were 'Highly Engaged Instruction', 'Well-structured class design', and 'Qualitatively superior class materials'. In other words, the pre-service teachers' views that well-structured class design and active interaction were the requirements of good science class. This study confirmed that pre-service teachers can draw images of good science class through experience of class demonstration and class evaluation.

• Journal of Korean Elementary Science Education
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• v.29 no.4
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• pp.427-440
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• 2010

The purpose of this study is to develop a science writing teaching strategy, and to apply it to the fourth-graders in elementary science classes. We examined its effect on their motivation, attitude, and understanding of science concept. For the research fourth grade children were grouped into three classes: an experimental class A of 27 children, an experimental class B of 24 and a comparative class of 27. All of them are from H elementary school in Seoul, Korea. Experimental class A learned science writing with a newly developed strategy while experimental class B learned science writing in a traditional method. Comparative class did not learn science writing. As a result, class A showed positive changes on students' science motivation, attitude, and understanding of science concept. In addition, class B with even one science writing task for a chapter had higher achievement in the understanding of science concept than the comparative class had.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.394-401
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• 2020

Purpose: The present study is an analysis of the extents of class satisfaction of college students who had applied the design thinking technique to capstone design class. Methods: The experimental method involved an analysis of 122 cases of data where advance and post replies were performed for the subject by students who had applied the design thinking technique and students who had not. The students involved had attended the capstone design class as a junior in the Department of Dental Technology at D University. Results: In the satisfaction with performance process of the capstone design class, five questions among nine had a high positive rating, while all eight questions on the satisfaction with performance methods had a high negative rating. Among ten questions on subjective learning outcomes, six showed a high positive rating. After the application of the design thinking class method, all mean values of the group with the application were higher than the group with no application in satisfaction with performance process, satisfaction with performance method, and subjective class outcomes. Hence, the design thinking class did have positive effects on the students' improvement of class. Conclusion: Based on the results of the study, it is implied that the considerations about diverse class composition methods and operation methods capable of improving the students' satisfaction are needed for efficient operation of the capstone design class.

• Korean Journal of Childcare and Education
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• v.13 no.1
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• pp.19-41
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• 2017

Objective: This study aimed to provide policy implications by studying the class size of early childhood education institutes. Methods: By looking through researches, the educational influence of class size was examined. By using the latest statistical data, class size standard and status were compared. After class size perception in the field was considered and the main results of advanced researches were summarized and analyzed, the actual condition of class size was diagnosed. Furthermore, the national research trend was analyzed. Results: First, class size was an influencing factor on young children and teachers and its importance was reconfirmed. Second, as for standard in relation to class size in Korea, the maximum class size and teacher-child ratio were not presented together. In respect of overseas standards, infancy has similar standards, but early childhood has a little higher ratio. In the educational fields, there was growing awareness that class size should be modified. Third, there were not enough domestic researches on class size and they tended to be biased in terms of the method, targets, and contents. Conclusion/Implications: It is suggested that it is necessary to establish a class size policy for future early childhood education institutes, to implement a system, and to perform follow-up studies.

• Journal of Korean Home Economics Education Association
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• v.7 no.2
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• pp.51-66
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• 1995

The purpose of this thesis is to expound reference data on class management such as class formation and so on by comparing Home Economics Education effect of coeducational class and one-sex class in the coeducational middle school. The major findings were follow: 1. More than half of those teacher who answered choose a coeducational class style as an effective class style(51.7%) because of active class atmosphere, preparation for future home life and getting over fixed sexual ideas by equal curricula content. 2. The results of research for basic knowledge about the Part of Food and Nutritional Science, which was conducted before the class, showed that the score of the one-sex class was higher than that of the coeducational calss(p<0.05) 3. The results of evaluation after class were as follows: The score of one-sex class was higher in the protein food group(p<0.01) and carbohydrate food group(p<0.05). The difference of each class in the calcium food group, the mineral and vitamin food group and the oil and fats food group was very small. The total score of two classes was of little difference.

• Journal of the Korean Mathematical Society
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• v.51 no.5
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• pp.1089-1104
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• 2014

An operator $T{\in}L(H)$, is said to belong to k-quasi class $A_n^*$ operator if $$T^{*k}({\mid}T^{n+1}{\mid}^{\frac{2}{n+1}}-{\mid}T^*{\mid}^2)T^k{\geq}O$$ for some positive integer n and some positive integer k. First, we will see some properties of this class of operators and prove Weyl's theorem for algebraically k-quasi class $A_n^*$. Second, we consider the tensor product for k-quasi class $A_n^*$, giving a necessary and sufficient condition for $T{\otimes}S$ to be a k-quasi class $A_n^*$, when T and S are both non-zero operators. Then, the existence of a nontrivial hyperinvariant subspace of k-quasi class $A_n^*$ operator will be shown, and it will also be shown that if X is a Hilbert-Schmidt operator, A and $(B^*)^{-1}$ are k-quasi class $A_n^*$ operators such that AX = XB, then $A^*X=XB^*$. Finally, we will prove the spectrum continuity of this class of operators.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.9-24
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• 1995

In this paper, we proposed and analysed two kinds of priority control mechanism to archive the cell loss rate requirement and the delay requirement of each class. The service classes of our concern are the high time priority class(class 1) and the high loss priority class(class 2). Two kinds of priority control mechanism is divided by the method of storing the arriving class 2 cell in buffer on case of buffer full. The first one is the method which discarding the arriving class 2 cell, the second one is the mothod which storing the arriving class 2 cell on behalf of pushing out the class 1 cell in buffer. In the proposed priority schemes, one cell of the class 1 is transmitted whenever the maximum K cells of the class 2 is transmitted on case of transmitting the class 1 cell and the class 2 cell sequentially. In this paper, we analysed the cell loss rate and the mean cell delay for each class of the proposed priority scheme by using the Markov chain. The analytical results show that the characteristic of the mean cell delay becomes better for the class 1 cell and that of the cell loss rate becomes better for the class 2 cell by selecting properly the cell transfer ratio according to the condition of input traffic.

• Journal of the Chungcheong Mathematical Society
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• v.24 no.1
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• pp.113-119
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• 2011

Let T be a bounded linear operator on a complex Hilbert space $\mathcal{H}$. An operator T is called class A operator if ${\left|{T^2}\right|}{\geq}{\left|{T^2}\right|}$ and is called class A(k) operator if $({T^*\left|T\right|^{2k}T})^{\frac{1}{k+1}}{\geq}{\left|T\right|}^2$. In this paper, we show that ${\sigma}$ is continuous when restricted to the set of class A operators and consider the tensor products of class A(k) operators.